APTD-1358
  VAPOR GENERATOR FEED PUMP
        FOR RANKINE CYCLE
AUTOMOTIVE PROPULSION SYSTEM
         U.S. ENVIRONMENTAL PROTECTION AGENCY

           Office of Air and Water Programs
          Mobile Source Pollution Control Program
            Ann Arbor, Michigan 48105
   LEAR MOTORS CORPORATION

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                                              APTD - 1358
                  VAPOR GENERATOR FEEDPUMP
                      FOR RANKINE CYCLE
                AUTOMOTIVE PROPULSION SYSTEM


                CONTRACT NUMBER 68-01-0437
                      FINAL REPORT


                      Prepared  By
                    Max K.  Winkler
                LEAR MOTORS CORPORATION
                  Reno,  Nevada   89510
                 EPA Project Officers
        W. Dyer Kenney and Kenneth F. Barber


                    Prepared For
        U.S. ENVIRONMENTAL PROTECTION AGENCY
          Office of Air and Water Programs
       Mobile Source Pollution Control Program
Advanced Automotive Power Systems Development Division
              Ann Arbor, Michigan  48105
                     December, 1972
                                            LEAR MOTORS CORPORATION

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The APTD (Air Pollution Technical Data) series of reports is issued by
the Office of Air and Water Programs, U.S. Environmental Protection
Agency, to report technical data of interest to a limited number of
readers.  Copies of APTD reports are available free of charge to Federal
employees, current contractors and grantees, and non-profit organizations
as supplies permit - from the Air Pollution Technical Information Center,
U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina 27711 or may be obtained, for a nominal cost, from the National
Technical Information Service, U.S. Department of Commerce, 5285 Port
Royal Road, Springfield, Virginia  22151.
This report was furnished to the U.S.  Environmental  Protection Agency by
Lear Motors Corporation, Reno, Nevada  in fulfillment of Contract Number
68-01-0437.  The contents of this report are reproduced herein as
received from the Lear Motors Corporation.  The opinions, findings, and
conclusions expressed are those of the author and not necessarily those
of the Environmental Protection Agency.
Office of Air and Water Programs Publication Number APTD - 1358
                                                  LEAR MOTORS CORPORATION

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                         TABLE OF CONTENTS


                                                                   PAGE

LIST OF TABLES	   i v

LIST OF FIGURES.	    v



SECTION

    I.   INTRODUCTION	    1

   II.   SUMMARY...	    2

  III.   TECHNICAL DISCUSSIONS	    6

          A.  Feedpump Operating Principle and Description	    6

          B.  Feedpump Design Study	    8

          C.  Feedpump Performance Study	   14

          D.  Material Compatibility Study	  '18

   IV.   SYSTEM CONTRACTOR TECHNICAL REQUIREMENTS AND LEAR MOTORS
          APPROACH

          A.  Steam Engine Systems - Water base fluid -
                Recriprocating Expander	   26

              1.  Pump performance	   27

              2.  Pump Inlet Envelope	   29

              3.  Pump Drive	   31

              4.  General Requirements	   33

          B.  Aerojet Liquid Rocket Company - Organic Fluid  -
                Turbine Expander	   34

              1.  Pump Performance	   35

              2.  Pump Inlet Envelope	   37

              3.  Pump Drive and Control  	   39

              4.  General Requirements	   41
                                                   LEAR MOTORS CORPORATION

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                       TABLE OF CONTENTS cont.

SECTION                                                            PAGE
          C.  Thermo Electron Corporation - Organic Fluid -
                Recriprocating Expander	    42
              1.   Pump Performance	    43
              2.   Pump Inlet Envelope	    45
              3.   Pump Drive and Control	    47
              4.   General Requirements	    49
    V.  CONCLUSION	    50
        REFERENCES	    52
        APPENDIX  - LEAR MOTORS PUMP STANDARDS	    53
              Pump Test Code	    ^-1
              Pump Rating Criteria	    A-5
              Net Positive Suction Head Definition	    A-8
              Net Positive Suction Head Calculations	    A-9
                                                   LEAR MOTORS CORPORATION 	
                                                                             111

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                          LIST OF TABLES



TABLE                                                              PAGE

    1.  Summary of Contract Technical Requirements	     3

    2.  System Contractor Feedpump Design Specifications	    13

    3.  Candidate Materials for System Contractor Proposed
          Feedpumps	    25
                                                   LEAR MOTORS CORPORATION  	
                                                                              iv

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                            LIST OF FIGURES
FIGURE
    1.
    2.

    3.
    4.
    5.
    6.
    7.
    8.
    9.
   10.
   11.
   12.
   13.
   14.
   15.
                                                           PAGE
Estimated System Contractors Feedpump performance.
Estimated Feedpump Performance and Typical  System
  Operating Envelope	
Lear Motors Feedpump and Typical  Test Stand..
LMC Feedpump Mechanical Efficiency vs. Flow..
LMC Feedpump Performance	
LMC Feedpump Net Positive Suction Head Chart.
SES Estimated Pump Performance	
SES Estimated Pump Inlet Envelope	
SES Pump Outl.ine Drawing	
ALRC Estimated Pump Performance	
ALRC Estimated Inlet Envelope	
ALRC Pump Outline Drawing	
TECO Estimated Pump Performance	
TECO Estimated Pump Inlet Envelope	
TECO Pump Outline Drawing	
 5
 7
15
16
17
28
30
32
36
38
40
44
46
48
                                                   LEAR MOTORS CORPORATION

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                               INTRODUCTION




        This report is submitted in fulfillment of Environmental

Protection Agency Contract No. 68-01-0437.  The data presented herein

are the results of preliminary design studies conducted to define

feedpumps that satisfy the performance requirements for Rankine

Cycle automotive power systems under development for the Environmental

Protection Agency.
                  SUMMARY OF SYSTEMS UNDER DEVELOPMENT
          System
        Contractor

   Steam Engine Systems
   CSES)

   Aerojet Liquid Rocket
   Company (ALRC)

   Thermo Electron
   Corporation (TECO)
    Working
    Fluid

Demineralized
water.

AEF-78
(Organic fluid)

Fluorinal 85
(Organic fluid)
   Type of
   Expander

Reciprocating
expander.

Turbine expander,
Reciprocating
expander.
                                                   LEAR MOTORS CORPORATION

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II  SUMMARY
         The approach followed  in this  study consisted  of establishing
    feedpump requirements for three (3)  separate  applications.   This  was
    accomplished in conjunction with the EPA and  the three system
    contractors.  The technical  requirements as established  by  the  contract
    and subsequent coordination meetings with the EPA and system contractors
    are summarized in Table I,  and detailed  in Section  IV.  An  additional
    requirement was to select a single  design which  satisfied both  organic
    systems.  However, the final  selection could  not compromise significant
    gains in performance or cost reductions  resulting from separate designs.
         Further investigations revealed that the feedpump developed  by
    Lear Motors Corporation satisfies the basic requirements of the three
    system contractors.   This Lear feedpump  was used as a baseline  for  the
    preliminary design and performance  study presented  in this  report.  A
    description of the Lear feedpump and its operating  principle is
    presented in Section III-A.   From the discussion presented  in
    Section III-A, it can be seen that  this  Lear  Motors pump has been
    designed for, and satisfies the basic requirements  of;  hermetic  sealing
    of the working fluid, contamination  of the working  fluid, variable
    displacement capability, and low N.P.S.H. capability.
         A summary of the flow requirements  and estimated brake horsepower
    for the three system contractor feedpumps is  shown  graphically  in
    Figure 1.  These data which show system  mass  flow and brake horsepower
    versus percent of expander speed illustrate the  relative magnitude  of
    the respective requirements.  Figure 2 shows  the estimated  feedpump
    performance, with a  typical  system  operating  envelope superimposed.
    These data show the affect of pump  displacement-speed relationship  on
    pump mechanical efficiency.
         Details of the contracts technical  requirements and the Lear
    Motors approach for each system contractor are presented in Section IV.
    These data, showing  the estimated pump performance, estimated pump
    inlet envelope, and  pump outline drawing were derived from  actual test
    results and physical relationships  of the Lear Motors 4th generation
    design feedpump.
                                                 LEAR MOTORS CORPORATION

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                                SUMMARY  OF   CONTRACT TECHNICAL REQUIREMENTS
                               SES
                                   ALRC
                                     TECO
Pump Performance

Type of Expander

Expander Speed


Flow Range and Corner
Condition

Discharge Pressure

Mechanical Efficiency


Pump Inlet Envelope

Inlet Pressure


NPSH Capability


Temperature Range


Temperature Transients

Boost Pump

Pump Drive

Drive Mechanism & Flow
Range Control


Working Fluid
Reciprocating

300-2500 RPM
0-2.5 6PM
Max system flow @ 40% speed

1200 PSIA max.

70% from 30-80% of flow max.
50% min. at 10% of flow max.
0.09 PSIA @ Start
7-50 PSIA operation

Minimized to operate
without boost

180-250 °F Normal
32-275 °F Start

3° per second for 10 seconds

Only if needed
Mechanical with provision
for;variable speed or
variable capacity.

Water - Demineralized
(Pump to have provision
for draining)
Turbine

16,800-31,200
1.85:1 Speed Ratio

0.5-28 GPM
Max system flow @ 54% speed

1100 PSIA max.

70% from 30-80% of max flow
50% min. at 10% of flow max.
1.0 PSIA @ Start
10.0-40.0 PSIA operation

7 inches min. avail
(.45 PSI @ 72 °F)

160-250 °F Normal
-40-275 °F Start
Only if needed
Mechanical with provision
for variable speed or
variable capacity.

Organic
S.G. = 1.793 @ 72 °F
Reciprocating

300-1800 RPM
0-17 GPM
Max system flow @ 45% speed

1000 PSIA max.

70% from 30-80% of max flow
50% min. at 10% of flow max.
0.5 (3 Start
5-90 PSIA during operation

10 inches min. avail.
(149 PSI @ 72 °F)

160-250 °F Normal
-40-275 °F Start
Only if needed
Mechanical with provision for
variable speed or variable
capacity.

Organic
S.G. = 1.368 @ 72 °F
                                                      TABLE  1

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0)
  ESTIMATE OF SYSTEM CONTRACTORS

        FEEDPUMP PERFORMANCE
    SYSTEM CONTRACTOR
    FLOW REQUIREMENTS
10
                   100
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                        ESTIMATED FEEDPUMP
                        BRAKE HORSEPOWER
10
      EXPANDER SPEED ~(%)
                       0   20  40  60  80


                          EXPANDER SPEED- (%)
                100

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    ESTIMATED FEEDPUMP PERFORMANCE
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     TYPICAL NORMAL
     OPERATING RANGE
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     EXPANDER SPEED^(%)




CONTRACT MECHANICAL EFFICIENCY DESIGN POINTS
TYPICAL NORMAL

OPERATING RANGE
                                         20    40    60    80


                                           PUMP MASS FLOW~(%)
              100

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Ill TECHNICAL DISCUSSION
         In Rankine cycle automotive power systems the feedpump must be
     capable of efficiently pumping the working  fluid  up to  system  pressure
     while operating at very low net positive suction  head conditions and
     very high fluid inlet temperature to achieve reasonable cycle
     efficiencies.   Three years ago, Lear Motors initiated the development
     of pump specifically designed for Rankine cycle applications.   The
     results of this development have been used  as the basis for these
     studies.
     A.  LEAR MOTORS FEEDPUMP OPERATING PRINCIPLE AND  DESCRIPTION
              The Lear Motors high pressure feedpump design, incorporates
         pistons reciprocating within close fitting cylinders filled with
         oil.  A flexible diaphragm is positioned between each cylinder
         cavity and the working fluid pump chamber. The alternate  suction
         and displacement of oil  by the pistons  actuates the diaphragms and
         thus results in an equal  displacement in the  working fluid chamber.
         No mechanical connection  is required between  diaphragm and piston.
              Since incompressable fluids are present  on both sides of the
         diaphragm, pressure across the diaphragm is always  equal.   The pump
         may be operated at any pressure within  the structual  limits of the
         pump without stress upon  the diaphragms or any reduction in
         diaphragm 1ife.
              The pump incorporates a fixed stroke, needle bearing, eccentric
         on a drive she.ft which is supported by  two ball bearings.   The
         eccentric converts shaft  rotary motion  to reciprocating motion and
         is used to drive the pistons which are  equally spaced around the
         drive shaft.  On the displacement, or pressure stroke, the eccentric
         drives the piston up, pressurizing the  oil chamber  above the piston
         which actuates the diaphragm and displaces the working fluid in the
         pump chamber through the  outlet valve.   During the  suction, or
         return stroke, the piston is held to the eccentric  by a positive
         return band and as the piston, oil and  diaphragm are drawn back,
         working fluid enters the  pump chamber through the inlet valve.
              The entire drive shaft and piston  assembly is  located within
         the pump's temperature compensating oil reservoir and is completely
         lubricated.  The oil filled chamber above the piston is connected
         to the oil reservoir through a slot in  the piston wall and a
                                                   LEAR MOTORS CORPORATION

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LEAR MOTORS TYPICAL TEST STAND
    LEAR MOTORS FEEDPUMP
FIGURE 3

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    triangular port in the side of the cylinder.   The  piston  slot  must
    be closed before oil  can be displaced  in  the  chamber  above  the
    piston.   That portion of fixed mechanical  stroke during which  the
    piston slot is closed is the effective stroke of the  pump.   By
    varying  the cylinder  port with respect to  the piston  slot,  the
    pump's effective stroke or displacement can be controlled.   Each
    cylinder is linked mechanically,  inside the pump,  to  an external
    pump displacement control  shaft which  can  be  actuated directly or
    with a small  servo mounted outside the pump.
         There are no sliding or rotating  seals in contact with the
    pumped fluid, allowing the pumped fluid to be hermetically  sealed
    from atmosphere and lubricating oil.   All  of  the highly stressed
    moving parts  in the pump are oil  lubricated allowing  conventional,
    low cost materials to be used throughout  its  construction.
    Efficient operation of the pump,  during low N.P.S.H.  conditions of
    Rankine cycle system, is made possible by  utilization of  large
    passages and  valves designed for  minimum  flow losses  throughout the
    inlet circuit of the feedpump.
         This feedpump, designed specifically  for use  with the  Rankine
    cycle system, is the result of a  continuing feedpump  development
    program at Lear Motors Corporation.
B.  FEEDPUMP DESIGN STUDY
         Pump size is determined primarily by  the system  flow require-
    ments as defined by the high flow-low  speed corner condition.  This
    point and the mass flow at idle define the mass flow-speed
    characteristics slope.  By extending the  line to 100% expander speed
    the flow capability of the pump is defined.   Since the system  can't
    utilize the total capability of the pump,  variable displacement or
    capacity is required  to allow operation within the system envelope.
         The corner condition of the  pump  performance  map is  determined
    by vehicle performance in terms of lugging and acceleration
    capability.  If system performance is  allowed to degrade  then  the
    slope of the  pump characteristics can  be changed.   Thus,  a  compromise
    in system performance is required if one  pump design  is used for
    both organic  fluid system contractors. For this study a  penalty
    in system performance was considered undesirable.   Therefore,  a
    separate pump design  was prepared for  each system  contractor.
                                              LEAR MOTORS CORPORATION 	
                                                                         8

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     After the high flow-low expander speed corner condition for
each system contractor was established, the maximum speed capability
of each pump was investigated based on an analysis of both radial
and axial piston pump designs.
     From this analysis it was determined that maximum speed
capability of the radial pump is limited by the valve dynamics and
speed at which the oil in the pump crank case may be sheared without
excessive friction losses, rather than the dynamic unbalance of the
fixed eccentric on the crank shaft.  Further study revealed that
the radial piston design would be physically smaller, lighter in
weight, and less expensive to produce.
     Utilizing the established maximum pump speed in conjunction
with the system contractor flow and maximum pressure ripple require-
ments, the bore/stroke relationship and number of cylinders were
selected.  To keep the instantaneous total flow of the pump, for any
given crank shaft angle, as smooth as possible, an odd number of
cylinders was used.  The number of cylinders and the bore/stroke
relationship determine the displacement of the pump as well as its
smoothness.  Obviously the greater the number of pistons for a
given flow the smoother the pump will be, however, pump cost and
physical size must be considered.  After close examination of the
parameters involved and based on our four years of feedpump
experience, the bore/stroke relationship and number of pistons
which would best meet the individual system contractor feedpump
requirements was determined.
     The diaphragm seals for each pump were then examined.  These
diaphragms are the key to the hermetic sealing capability of the
Lear Motors feedpump design.   They also enable the pump to produce
high pressure working fluid without utilizing the fluid to lubricate
highly stressed moving components such as piston seals, gear teeth,
or vane tips.  The diaphragm effective area selection was based on
several factors:  1)  The maximum volume it must displace during
each piston stroke.  2)  The physical design of the seal .  3)  The
material used to construct this flexible sealing member.
     As the Lear Motors feedpump has demonstrated excellent per-
formance with a flat circular sealing member using an elastomer
material, our major effort was directed toward finding elastomers
                                          LEAR MOTORS CORPORATION

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which had the physical properties required and were compatible with
the two organic fluids used by the system contractors.
     A separate study was conducted and limited tests for compatibil-
ity were conducted by the organic fluid system contractors on
candidate elastomer materials selected and supplied by Lear Motors
Corporation.  The results of this study indicated that several of the
elastomers evaluated, were acceptable for use as sealing diaphragm
material.  The suggested procedure and test results are shown in
Section III-D of this report.
     An additional investigation into the possible use of a bellows
type metal diaphragm was carried out.  However, due to the low cycle
life and high costs quoted by the venders and available design
literature, the use of this type of seal was deemed not practical.
     Having established a suitable elastomer material  for each of the
system contractors and selected the flat circular diaphragm design,
the minimum effective area required for long diaphragm life was
determined.  It is apparent that for a given piston displacement the
larger the effective or flex area of the sealing diaphragm, the longer
the diaphragm life.  However, the physical size of the pump, namely its
outside diameter, will become proportionately larger.   Therefore, the
minimum area of diameter of the diaphragm becomes an important
individual pump design feature.  This sealing member is simply a
flexible incompressible barrier which separates two other virtually
incompressible fluids; the most important physical  characteristic of
the elastomer sealing or separating members used in these pumps is
the flex life capability of the elastomer.  Fortunately, this is
what most elastomers are compounded for and the selection of materials
is large even when limited by the Rankine cycle system fluid tempera-
ture extremes and material compatibility requirements.
     The designed maximum movement or flex used by Lear Motors is
8 to 10 percent change.   For each system contractor a  specific
diaphragm effective area was determined based on the maximum volume
displaced per piston and the 8 to 10 percent flex value which has
proved successful  in the Lear Motors feedpump.   It must be pointed
out that during most of the vehicles normal  operation  the feedpump is
                                             LEAR MOTORS CORPORATION 	
                                                                       10

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functioning at a reduced displacement and the diaphragms would be
flexing less than design.
     Having determined the individual system contractors pump, bore
and stroke, number of cylinders, pump speed, and outside diameter
required by the pitch circle of the individual diaphragm seals, a
preliminary analysis of each pumps bearing requirements and operating
mechanics was made.  As one of the basic strong points of the Lear
Motors feedpump design is that all of the highly stressed bearings and
moving parts required by the feedpump are oil lubricated, conventional
low cost bearings and materials may be used, making the analysis of
the lubricated section of the pump straight forward.  One area in this
lubricated section required special attention.  The pumps unique
outlet flow or displacement control, described in Section III-A
Feedpump Operating Principle and Description, must be designed to keep
orifice and passage losses low to maintain high pump mechanical
efficiency.
     The next basic area which was examined during this design and
performance study involved the inlet passages and inlet valve sizing.
To reduce the net positive suction head required by the pump for
efficient operation, special  attention must be given the working fluid
inlet of the pump.  A description of the term net positive suction
head (NPSH) is given in the appendix.  Basically, a positive displace-
ment pump is not known for its low NPSH characteristics; any entrained
vapor in the pumped fluid will cause the pump performance to degrade
rapidly.  To minimize the NPSH required by the feedpump, the inlet
velocity of the working fluid must be kept as slow as possible so that
the friction losses are kept to a minimum.  Also the inlet valve
spring must be kept as light as possible and still allow the valve to
operate at high pump speed.  Large inlet passages and inlet valves
which reduce fluid flow velocities were designed into each of the
feedpumps.  Maximum inlet velocities of 5 to 6 feet per.second were
used in the design of the Lear Motors feedpump and each of the system
contractor feedpumps.  The estimated inlet envelope showing the NPSH
required for each of the pumps is detailed graphically in Section IV
of this report.  These data,  corrected for individual  organic fluid
specific gravity variations,  demonstrate what each of the pumps would
be capable of based on actual  Lear Motors test data shown in
                                            LEAR MOTORS CORPORATION 	
                                                                       11

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 Section III-C of this report.
      Further examination of the NPSH required by these feedpumps,
 although low for positive displacement pumps, indicates that some
 amount of sub-cooling or boost pressure is required to meet the
 system contractor requirements.  Sub-cooling of the working fluid
 results in a significant loss in Rankine cycle system efficiency due  to
 the power expended in the cooling of the fluid as well  as  the heat
 required to bring it back up to a temperature after it has been
 pumped.  Adding boost pressure or head to the inlet of the pump by
 placing the working fluid reservoir physcially higher than the
 feedpump is not practical in an automotive Rankine cycle system due
 to the limits of the engine compartment and the added expander back
 pressure.  However, increasing the inlet pressure to the feedpump  with
 an independently driven centrifugal pump demonstrates several
 advantages; the centrifugal  type of pump has inherently low NPSH
 characteristics and can be designed to handle significant  amounts  of
 vapor.  A centrifugal  pump can operate at and below the systems
 working fluid vapor pressure line, allowing greater cycle  efficiencies
 through the minimum sub-cooling required.  By mounting a small
 separately driven centrifugal  pump low in the system the feedpump  may
 be conveniently mounted and  driven without regard to the systems
 liquid level.  The vehicle will be operational  with the absolute
 minimum sub-cooling because  the independently driven centrifugal pump
 will  provide some liquid to  the feedpump regardless of the expander
 speed.  An independently driven centrifugal  boost pump will  allow  the
 system to be started after a hot shutdown.   It was concluded after
 examining the parameters involved that a small  independently driven
 centrifugal pump is important to the efficient operation of an
 automotive Rankine cycle system.
      Having concluded  the preliminary design portion of this study,
 an outline or installation drawing for each pump, shown in Section IV,
 was drawn.  It must be pointed out that these pumps were designed
 specifically to meet the individual system contractors  requirements
 and that their physical  size is determined  primarily by the systems
 high flow-low speed corner condition not just the maximum  system flow
 required.
      Example:  A positive displacement pump  with  flow-speed
	 LEAR MOTORS CORPORATION  	
                                                                       12

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                           SYSTEM CONTRACTOR FEEDPUMP

                             DESIGN SPECIFICATIONS
Configuration
Number of
Cylinders

Bore

Effective Stroke

Diaphragm seal
effective are
per cylinder

Pump Design
Theoretical Flow
0 85% Vol. Eff.

System Flow
Requirement

Pump Speed
(Max. Design)

Pump Displacement
VoT/Rev.

Inlet Velocity
@ Max System Flow

Estimated Pump
Weight with
1.  Iron Housing
2.  Aluminum
    Housing*
  SES

Radial Piston,
Diaphragm seal
6.2 GPM @ 100
percent speed
2.5 GPM @ 40
percent speed

2400 RPM
 .77 in3/Rev.
5.1 FPS
16 1/2 pounds
12 pounds
  AJLRC

Radial Piston,
Diaphragm seal
52 GPM @ 100
percent speed


28 GPM @ 54
percent speed

2000 RPM


6.52 in3/Rev.


5.9 FPS
108 pounds
 81 pounds
  TECO

Radial Piston,
Diaphragm  seal
.68 inches
.41 inches
2.08 in2
1 .25 inches
.75 inches
6.51 in?
1 .18 inches
.67 inches
5.43 in2
40 GPM @  100
percent speed


17 GPM (3  45
percent speed

2000  RPM


4.64  in3/Rev.


5.5 FPS
66 pounds
46.5 pounds
 Additional stress analysis required.
                                     TABLE 2
                                                                                13

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    characteristics capable of producing 26 GPM (gallons  per minute)  at
    50 percent or one-half speed is theoretically capable of producing
    52 GPM at 100 percent or maximum speed.  While the system may only
    require 26 GPM mass flow the pump must be physically  large enough to
    produce 52 GPM.  The only reduction in pump size,  due to the 26 GPM
    system requirement, will be working fluid flow passage area.  From
    this example it can be seen that any reduction of  the system
    contractors high flow-low speed corner requirement will  result in a
    significant reduction in the feedpump size and weight.
C.  FEEDPUMP PERFORMANCE STUDIES
         Estimates of the individual system contractor proposed feedpumps
    performance and inlet envelope are shown graphically  in Section IV.
    These estimates were obtained by extrapolating actual Lear Motors
    Corporation feedpump test data.  The procedure and feedpump rating
    criteria used in conducting the tests, which were  run specifically
    for this study, are shown in the Appendix.
         The proposed feedpump estimated performance curves, showing  pump
    brake horsepower, mechanical efficiency, and flow  vs. pump and ex-
    pander speed, demonstrate the broad range over which  these pumps  can
    operate.  The lower section of these pump performance maps, indicate
    the flow characteristics of the pump at various speeds and displace-
    ment levels.  Superimposed are the 50 and 70% mechanical efficiency
    lines denoting how the pump performs with respect  to  contractor
    performance requirements.  Also indicated is the pumps full displace-
    ment flow line the slope of which is determined by the individual
    system maximum flow-minimum expander speed corner  condition and the
    volumetric efficiency of the pump.  Based on Lear  Motors Corporation
    feedpump data, full displacement volumetric efficiency of the proposed
    pumps will be 85 to 90% depending on outlet pressure  and inlet
    N.P.S.H.
         Feedpump inlet envelope estimates are also shown in Section  IV,
    under the individual system contractor heading. These inlet envelopes,
    superimposed over the contractors working fluid vapor pressure
    characteristics, demonstrate the N.P.S.H. required by the pump to
    maintain efficient operation.  The pressure and temperature limits
    during normal and extreme operating conditions, as outlined by the
                                                LEAR MOTORS CORPORATION
                                                                          14

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                                     MECHANICAL EFFICIENCY VS PUMP FLOW
                                        Silver 4-cv Bus Pump

                                        Test Conditions:

                                          Outlet Press.-- 1000 PSIG

                                          Suction Press.- 15 PSIG

                                          Water Temp.	 75-90°
                                          Mech. Eff.=  W-H-P- x ion
                                   456


                                PUMP  FLOW~ GPM
                                                                 FIGURE 4
                                                                                   15

-------
                  20
30
                               40      50     60
                             PUMP  SPEED -- PER CENT
70
80
90
100
                                   Full Displacement Mech. Eff.
         PUMP  PERFORMANCE
            4-CV  Bus  Pump
            Test  Conditions:
              Outlet  Pressure -
              Suction Pressure-
              Water Temp. -  - -
      - 1000 PSIG
      - 15 PSIG
      - 100-160° F
s
o
\
CX,
s
d.
10

 9

 8

 7

 6

 5

 4

 3

 2

 1
                  20
30
                              40      50     60
                            PUMP SPEED - PER CENT
70
80
90
                        100

                        90

                        80  \

                        70  I
                           M
                        60  M

                        50  w
                           _]
                        40  3

                        30  |

                        20  s
                                                      707.
                                                      Mech
                                                      Eff
                                                      50%
                                                      Mech
                                                      Eff
                                                   100
          200     400     600    800    1000    1200
                         "        PUMP SPEED ~ RPM
                             1400   1600    1800    2000
                                              FIGURE  5
                                                                                    16

-------
92.5
S2.5-
                          NET  POSITIVE  SUCTION HEAD  (NPSH) CHART
                          Fluid  - Water
                          Conditions  -  5000  Ft Altitude
                  NPSH = hs-(hvp-ha)
                    Where:
                      hs=Static Suction Head
                         at Pump Inlet (Gage)
                         =Vapor Pressure (Absolute)
                      ha=Atmospheric Pressure
                         (Absolute)
                                                                                          O -- DATA POINTS
                                                                                               PUMP SPEED 1260 RPM
                                                       Open Pot
                                                       Boiling Point of
                                                       Water @ 5000 Ft.Alt.
                                                       (12.5 PSIA @ 204° F Nominal)
150
                   160
210    220
 TEMPERATURE -
                                                                                               280
290

-------
    contract requirements, are also indicated.
         Minimum N.P.S.H. characteristics shown were taken directly from
    Lear Motors feedpump data, corrected only for the individual
    contractors working fluid specific gravity.  It has been our
    experience, as pointed out in the feedpump design studies,  that while
    the minimum N.P.S.H. characteristics of the Lear Motors feedpump
    design is low, significant gains in Rankine cycle efficiency  are
    obtained by using an externally driven boost pump designed  to handle
    even lower N.P.S.H. conditions.
D.  MATERIAL COMPATIBILITY STUDY
         The proposed feedpumps utilize a flexible diaphragm to provide
    positive hermetic sealing of the working fluid from the atmosphere
    and oil contamination.  Lear Motors Corporation has found that many of
    the common elastomers demonstrate all of the physical  qualities
    necessary to effect this seal.  However, compatibility with the
    working fluid must be established.
         At the first contract coordination meeting, due to the small
    number of elastomers which had been tested, it was decided  that each
    of the organic fluid system contractors should perform compatibility
    tests on candidate elastomers and non-metallic materials.  Samples
    of the candidate materials and a suggested test procedure were pro-
    vided by Lear Motors Corporation.
         The compiled results of these tests as well as additional  data
    from the system contractors and an organic fluid manufacturer  are
    shown.  A summary of the elastomers which are acceptable for  the
    feedpump sealing diaphragms follows:
    THERMO ELECTRON CORPORATION - Organic Working Fluid-Fluorinol 85
         Elastomers which have passed initial compatibility tests with
    the TECO.organic working fluid at 250°F.
         1.  Silicone Rubber, Parker-Compound No. S455-7.
    AEROJET LIQUID ROCKET COMPANY - Organic Working Fluid  AEF-78
         Elastomers which have passed initial compatibility tests with
    the ALRC organic working fluid at 250°F.
         1.  Silicon-Rubber - (Dow Corning L-53).
         2.  Silicon Rubber - (Dow Corning L-63).
                                                LEAR MOTORS CORPORATION
                                                                          18

-------
     3.  Chloroprene Rubber - (Dupont "Neoprene").
     4.  Polysulfide Rubber - (Thiokol Chemical Corp.).
     The results of these preliminary tests have demonstrated that
elastomers for use with the organic working fluids are available.
However, due to the short term and limited scope of these tests, Lear
Motors recommends additional investigations.
                                            LEAR MOTORS CORPORATION  	
                                                                      19

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                     Results of Material  Compatibility

                   Tests Performed by Thermo Electron Corp.
Test Conditions:

     Solution -
     Temperature -


    LMC Candidate
      Material

Chloroprene Rubber
Florinol  85 and oil  (10 to 1  ratio)
250°F
      Percent Weight
          Change

           + 6.8
 Time
(days)

  17
Nitrel
           + 8.3
  17
Polyimide
(Dupont) Vespel SP-1
Polyamide DFS-20
(experimental-Dupont)
CONCLUSIONS
           + .48
           + .  11
   Visual Observations
Surface corroded, small pin
holes, but still strong.
Liquid yellow with small
black particles hanging,
white particles sticking on
glass.

Grey color at bottom in
liquid F-85 immersed portion,
also softer at bottom.  White
spots  scattered on surface,
white line at interface
liquid yellow black colored,
with some fine white parti-
cles hanging.

Color changed to a darker
brown, material stron, F-85
and oil light brown, very
few suspended fine fibers.

Very few brown spots at
bottom, more yellow colored
material, slightly softer,
oil and F-85 light brown.
     1.  Neither Neoprene nor Nitrel  Rubber should be used in the presence of
         F-85 liquid and oil at 250°F.

     2.  SP-1 Polyimide may be used in the system at 250°F but preferably a
         lower temperature in the presence of F-85 liquid and oil.   It
         showed about 0.44% swelling.

     3.  High temperature Polyamide DFS-20 may be used in the system at 250°F
         or a lower temperature in the presence of F-85 liquid and  oil.  It
         showed about 1.1% swelling with very light softening.


                   'Based on personal  correspondence between  Luco R.  DiNanno,
         Development Engineer for Thermo Electron, Corp, and  writer,
         September 13, 1972.
                                                   LEAR MOTORS CORPORATION
                                                                            20

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                    Results of Material  Compatibility
                                                           o
                  Tests Performed by Thermo Electron Corp.
Test Conditions:
     Solution -       Fluorine!  85 and lubricating oil  10 to 1  ratio
     Temperature -    250°F
     Duration -       17 days
    Material                  Visual  Observation

Dow Corning, LS53,            The rubber was much softer,  lightly attack at
Fluorosilicone Rubber         bottom  in liquid immersed portion,  brownish
(-2" x 0.07" O.D.)            material  was sticking on glass and  liquid
                              F-85 turned to very light brown.

Dow Corning LS63,             The rubber was much softer,  lightly attack in
Fluorosilicone Rubber         liquid  immersed portion.  F-85 turned very
(1.5" x 0.1" O.D.)            light brown.

Parker No. S455-7             The rubber was lightly softer, no apparent
Silicon Rubber                change, F-85 turned light brown.
(2" x 0.1" O.D.)
RECOMMENDATIONS:

Silicone Rubber - Parker No. S455-7 is recommended to be used in the system
at temperature not exceeding 250°F in the presence of F-85 solution and air,
                Based on correspondence between Dyer Kenney, Contract
     Project Officer for Environmental  Protection Agency, and writer
     October, 1972.
                                                   LEAR MOTORS CORPORATION 	

                                                                             21

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  Material Compatibility Information on Elastomers Obtained from the Fluid

                 Manufacturer - Halocarbon Products Corporation


Test Conditions:

     Solution -       Fluorinol 85
     Temperature -    284°F
     Duration         7 days


    Material                % Height Change          % Thickness Change

Ethylene-Propylene Rubber    1.3 to 2.6                1.1  to 1.5

Silicone Rubber              4.7 to 11                  2.6  to 3.4

Neoprene                     15 to 16                  5.2  to 10

Pure Gum & Polyisoprene      20 to 46                  8.8  to 16

Flurosilicone Rubber         1.6 to 49                 -23  to 18

Viton A                      34 to 54                  13 to 15

Butyl                        16                        7.0


Completely Unsatisfactory:   Buna N, Buna S and Hypalon.
               3Based on correspondence between Mr. Rex Conner,  Halocarbon
     Products Corporation and writer, August, 1972.
                                                   LEAR MOTORS CORPORATION 	
                                                                             22

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                     Results of Material Compatibility Tests
                     Performed by Aerojet Liquid Rocket Co.
Test Conditions:
     Solution -
     Temperature -
     Duration -
AEF-78 (A.LRC working fluid)
250°F
150 hours
LMC Candidate Materials
Neoprene (Diaphragm. Stock)
Delrin (Dupont)	
Vespel SP-1 Polyimide (Dupont)
Vespel SP-21 Polyimide (Dupont)
Polyamide DFS-21, Experimental (Dupont)
Nitrel (Diaphragm Stock)	
Viton (Diaphragm Stock)	
Polyamide DFS-20, experimental (Dupont)_
Natural Rubber (A.B. Boyd)	
Silicone
Polyurethane (Newage Industries)_
                            Test Results
                            _Marginal
                            _Not Acceptable
                            Good
                            Good
                            Good
                            _Not Acceptable
                            _Marginal
                            Good
                            _Not Acceptable
                            Good
                            _Marginal
               4Based on telephone conversation between A.H. Kreeger,
     Manager Automotive Rankine Program, Aerojet Liquid Rocket Co. and
     writer, November, 1972.
                                                    LEAR MOTORS CORPORATION
                                                                              23

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              Results of Elastomer Material Compatibility Tests
                   Performed by Aerojet Liquid Rocket Co. 5
Test Conditions:
     Solution -
     Temperature -
     Duration
AEF-78
250°F
Long Term
Elastomer

Silicon Rubber (Dow Corning L-53)

Silicon Rubber (Dow Corning L-63)

Silicon Rubber (Parker HS 455-7)_

Florosilicon Rubber.	

Chloroprene Rubber	
Polysulfide (Thiokol Chemical Corp.)
                          Test Results

                          Good
                          Good
                          Good
                         _Not Acceptable
                          Good
                          Good
               5Based on telephone conversation between A.H. Kreeger,
     Manager Automotive Rankine Program, Aerojet Liquid Rocket Co. and
     writer, September, 1972.
                                                   LEAR MOTORS CORPORATION
                                                                             24

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                              CANDIDATE  MATERIALS  FOR SYSTEM
                            CONTRACTOR LMC  PROPOSED  FEEDPUMPS
Component
Manifold
(Inlet & Outlet)
Valve Plate
Outlet Valve
Inlet Valve
Valve Spring
(Inlet & Outlet)
Seals
(Enclosed & Static)
Diaphragm Seal
 Materials for Working
   SES

Cast 356 Aluminum
Stainless Steel
Type 303
Aluminum 6061-T6
Aluminum 6061-T6
Stainless Steel
Type 804
Nitrile Rubber

"Hydrin" Rubber
Fluid Section of Feedpump
    ALRC                  TECO
 Cast 356 Aluminum     Cast 356 Aluminum
 Stainless Steel
 Type 303
 Aluminum 6061-T6
 Aluminum 6061-T6
 Stainless Steel
 Type 804
 Silicone Rubber
Stainless Steel
Type 303
Aluminum 6061-T6
Aluminum 6061-T6
Stainless Steel
Type 804
Silicone Rubber
 l.Silicone  Rubber*    Silicone Rubber*
 2. Polysulfide  Rubber*
                   Material  for1 Oil  Lubricate Section of Feedpump
Feedpump Housing

Bearings
(Drive Shaft)
Drive Shaft
Pistons
Bearings (Piston)
Cylinders
Seals
1.  Cast Ductile Iron
2.  Cast Aluminum
    356-T6**
 1.  Cast Ductile Iron 1,
 2.  Cast Aluminum     2,
     356-T6**
    Cast Ductile Iron
    Cast Aluminum
    356-T6**
Steel (Anti-Friction)   Steel (Anti-Friction) Steel (Anti-Friction)
Carborized 4620 Steel
Carborized 1117 Steel
Aluminum Bronze
Cast Nodular Iron
Buna "N" Rubber
 Carborized 4620 Steel  Carborized 4620  Steel
 Carborized 1117 Steel  Carborized 1117  Steel
 Aluminum Bronze        Aluminum  Bronze
 Cast Nodular Iron      Cast  Nodular  Iron
 Buna "N" Rubber        Buna  "N"  Rubber
         *   Preliminary selection based on limited material  compatibility study,
         **  Additional stress analysis required.
                                    TABLE 3

-------
STEAM ENGINE SYSTEMS TECHNICAL REQUIREMENTS AND



         LEAR MOTORS CORP. APPROACH
         VAPOR GENERATOR FEEDPUMP



        FOR RANKINE CYCLE AUTOMOTIVE



             PROPULSION SYSTEM
       EPA CONTRACT NUMBER  68-01-0437



             December 1972
                                      LEAR MOTORS CORPORATION

-------
                           STEAM ENGINE SYSTEMS

                             PUMP PERFORMANCE
TECHNICAL REQUIREMENTS
     1.  Expander Speed  The speed of the reciprocating expander during
         operation will vary from a minimum of 300 rpm to a maximum of
         2500 rpm.

     2.  Flow  The flow range shall be from 0 to 2.5 gpm.  Maximum system
         flow (2.5 GPM) shall occur at 40 percent of maximum expander speed
         The feedpump shall be capable of modulating upon command from the
         propulsion control system to satisfy any flow condition within the
         the operating range specified.  The feedpump shall be capable of
         operating with no inlet flow for periods up to one minute without
         damage.

     3.  Discharge Pressure  The feedpump shall  be capable of delivering
         flow as specified, while discharging to a pressure of 1200 psia.
         The discharge pressure shall  be stable with no high frequency
         oscillations in excess of 25 psia.

     4.  Efficiency  The feedpump mechanical efficiency shall be 70% or
         greater over the flow range from 30% to 80% of maximum design
         flow.  The mechanical  efficiency shall  be 50% or greater at 10%
         of maximum design flow.

     5.  Fluid  The working fluid for this system will be demineralized
         water.
TECHNICAL APPROACH

     The estimated performance curves, on the following page, demonstrate
how the proposed LMC feedpump would meet the SES   technical requirements
shown above.  This estimate was obtained by extrapolating actual  LMC
feedpump data.

     The maximum pressure ripple requirement is met by utilizing  an odd
number of cylinders which are sized so that the instantaneous total flow of
the pump for any given crank angle is as smooth as possible.

     Additional information regarding the LMC technical approach  to the SES
feedpump performance requirements may be found  in the technical discussions
section of this report.
                                                  LEAR MOTORS CORPORATION 	

                                                                             27

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        20
                         30
40     50      60
 SPEED -' PER CENT
70
80
90
100
a
o
\
o
fa
      Full Displacement Mech.
           ESTIMATED FEEDWATER PUMP PERFORMANCE
           EPA Contract No. 68-01-0437
           System Contractor-Steam Engines Systems Corp.
             Conditions:
             Outlet Pressure .... 1200 PSIG
             Suction Condition ... 5 PSI Min. N.P.S.H.
             Fluid Temp.     .... 160-250°F
    O System Max. Flow -
       Low Speed Corner Requirement
                       40      50     60      70
                      EXPANDER SPEED - PER CENT
                                                              80
                                     90
                                                                              100

                                                                              90

                                                                              80

                                                                              70
                                                                        O
                                                                        z
                                                                        w
                                                                        M
                                                                        O
                                                                    60  £
                                                                        w
                                                                              50

                                                                              40
                                                                        O
                                                                    30

                                                                    20
                                                                    707»
                                                                    Mech.
                                                                    EFF.
                                                                    507«
                                                                    Mech.
                                                                    EFF.
                     100
240    480     720    960    1200   1440    1680   1920   2160   2400
                       PUMP SPEED ^ RPM
       500
                               1000           1500
                              EXPANDER SPEED - RPM
                            2000
                     2500

                 FIGURE 7
                                                                         28

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                         STEAM ENGINE SYSTEMS

                         PUMP INLET ENVELOPE
TECHNICAL REQUIREMENTS

     1.  Inlet Pressure  The minimum pressure at the pump inlet valve
         during start-up maybe as low as 0.09 psia.   During system
         operation, the inlet pressure may vary from a minimum of 7 psia
         to a maximum of 50 psia.

     2.  Net Positive Suction Head  The net positive suction head required
         by the feedpump shall be minimized so that  the pump can operate
         without cavitating under low liquid head conditions without the
         necessity of a boost pump.

     3.  Temperature Range  During system operation, the temperature of
         the working fluid may vary from 180°F to 250°F.  At system
         start-up the temperature of the working fluid may vary from 32°F
         to 275°F.

     4.  Temperature Transients  The feedpump shall  stand feedwater
         temperature transients of 3°F per second for periods of 10 seconds
         without cavitating.

     5.  Booster Pump  A booster pump for providing  the required net
         positive suction head to the feedpump shall be considered only
         if trade-off studies conducted by the contractor reveal that the
         utilization of a boost pump will simplify the feedpump design
         sufficiently to offset the additional cost, weight and power
         consumption required by the boost pump.


TECHNICAL APPROACH

     The estimated pump inlet envelope on the following page shows the
Lear pump capability while operating at the 85% to 90% volumetric
efficiency level.  The N.P.S.H. values shown are taken from actual data.
RECOMMENDATIONS

     Due to the inherent lower N.P.S.H. characteristics of a centrifugal
pump and its ability to handle large quantities of entrained vapor,  a
separate centrifugal boost pump is recommended for this system.   The size
and characteristics of this pump will  require a trade-off study  of the
system condenser capability and the amount of sub-cooling allowable  before
significant decreases in cycle efficiency occur.
                                                  LEAR MOTORS CORPORATION  	

                                                                             29

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    112.5
    102.5-
     92.5-
    82.5-
100
 90
 80
00
ESTIMATED FEED PUMP INLET ENVELOPE
   Fluid - Water
   Conditions - 5000 Altitude
   System Contractor-Steam Engine Systems
                                                                       Normal
                                                                      'Operating
                                                                       Range
                                                                       \ \l \
                                                                          Open Pot  Boiling Point of
                                                                          Water @ 5000  Ft.  ALT.
                                                                          (12.5 PSIA @  204°F  Nominal)
                       20  I 40   60    80   100   120  140   160   180  200   220  240  260  280  300  320
                          32
                                                    TEMPERATURE  -  °F

-------
                          STEAM ENGINE SYSTEMS

                              PUMP DRIVE
TECHNICAL REQUIREMENTS

     1.  Drive Mechanism  The feedpump shall be mechanically driven with
         power taken from the expander shaft or gearbox.  The feedpump
         shall provide the total range of required flow and pressure with
         the expander operation at any speed within its specified speed
         range.  The non-linear relationship between expander speed and
         required feedpump flow and pressure shall be accommodated by
         variable drive mechanism characteristics and/or variable feedpump
         and drive mechanism should be capable of being mounted in the
         power plant as required by the system contractor.
TECHNICAL APPROACH

     An outline drawing of the proposed Lear Motors Pump is shown on the
following page.  The pump has variable displacement capability and can be
directly driven by the expander.  Pump to expander speed ratio and interface
are not firm and will have to be worked out between Lear Motors and the
system contractor.

     Pump physical size is based on the contracts pump performance
requirements, i.e. flow rate, and any change in the design flow rate will
directly affect pumps physical size and weight.
                                                  LEAR MOTORS CORPORATION  	

                                                                             31

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OUTLINE DWG.,
         PUMP -SCS/

-------
                          STEAM ENGINE SYSTEMS

                          GENERAL REQUIREMENTS
TECHNICAL REQUIREMENTS

     1.  Vehicle Design Goals  Where applicable, "Vehicle Design Goals-
         Six Passenger Automobile", shall be used as a guide for the design
         requirements.

     2.  Materials  All materials utilized in the construction of the
         feedpump shall be corrosive resistant in a water/air environment.

     3.  Lubrication  Any lubricants that may be used within the feedpump
         and its drive mechanism shall  not mix with or contaminate the
         working fluid.  The lubricant shall be the same as that used in
         the expander.

     4.  Leakage  There shall be no external leakage from the feedpump and
         its drive mechanism.  The unit shall be capable of being
         hermetically sealed.

     5.  Working Fluid Drainage  The feedpump shall be designed such that
         all working fluid within the pump will drain back out of the
         inlet side of the pump into the system sump at shutdown.  Care
         should be taken to assure that all pockets of fluid are adequately
         drained to prevent damage due to freezing.
TECHNICAL APPROACH

     The Lear Motors pump design, with its flexible diaphragm seal  provides
inherent hermetic sealing of working fluid from the air and lubricated
section of the pump.

     Working fluid drainage requirement will be met by unseating the inlet
valves at system shutdown allowing the fluid in each chamber to drain back
to the inlet manifold.  This approach would not degrade the pumps
performance and would be integral to the pump.

     Materials used for the construction of the proposed SES feedpump are
shown in Table 3.  The material used for the pumps flexible sealing member
can be constructed from almost any elastometer which can meet the temperature
requirements and is compatible with the working fluid.
                                                  LEAR MOTORS CORPORATION  	

                                                                            33

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AEROJET LIQUID ROCKET COMPANY TECHNICAL REQUIREMENTS AND
           LEAR MOTORS CORP. APPROACH
             VAPOR GENERATOR FEEDPUMP
            FOR RANKINE CYCLE AUTOMOTIVE
                 PROPULSION SYSTEM
           EPA CONTRACT NUMBER 68-01-0437
                  DECEMBER 1972
                                         LEAR MOTORS CORPORATION 	
                                                                    34

-------
                   AEROJET LIQUID ROCKET COMPANY

                        PUMP PERFORMANCE
TECHNICAL REQUIREMENTS

     1.  Speed Range  The speed of the turbine expander will vary from a
         minimum of 16,800 rpm to a maximum of 31,200 rpm.  This same
         speed ratio (1.85:1) will be available from the expander gearbox,
         if required.

     2.  Flow  The feedpump and its drive mechanism shall be capable of
         delivering a constant flow of organic fluid from a minimum of
         0.5 gpm to a maximum of 28 gpm at a discharge pressure from 650
         psia to 1100 psia and at any given expander speed within the range
         specified.  Maximum system flow (28 gpm) shall occur at 59 percent
         maximum expander speed.

     3.  Discharge Pressure  The feedpump shall be capable of delivering
         flow as specified while discharging to a pressure of 1100 psia.
         The discharge pressure shall be stable with no high frequency
         oscillations in excess of 25 psi.

     4.  Efficiency  The feedpump mechanical efficiency shall be 70% or
         greater over the flow range from 30% of maximum design flow to
         80% of maximum design flow.  The mechanical efficiency shall be
         50% or greater at 10% of maximum design flow.

     5.  Fluid  The working fluid will be a non-corrosive organic fluid
         with a density of approximately 100 Ibs/ft^.


TECHNICAL APPROACH

     The estimated performance curves, on the following page, demonstrate
how the proposed LMC feedpump would meet the ALRC technical requirements
shown above.  This estimate was obtained by extrapolating actual LMC
feedpump data.

     The maximum pressure ripple requirement is met by utilizing an odd
number of cylinders which are sized so that the instantaneous total flow
of the pump for any given crank angle is as smooth as possible.

     Additional information regarding the LMC technical approach to the
ALRC feedpump performance requirements may be found in the technical
discussions section of this report.
                                                  LEAR MOTORS CORPORATION 	
                                                                            35

-------
                                                                             <4U
                               40     50      60
                               SPEED -" PER CENT
                                                70
                                                               80
       90
       LOO
o
\

Cn
(Xc
S
PL,
52

48

44

40

36

32

28

24

20

16.

12

 8

 4

 0"
                  Displacement Mech
     ESTIMATED FEEDWATER PUMP
              PERFORMANCE
        EPA  CONTRACT  NO. 68-01-0437
        System Contractor-
         Aerojet  Liquid Rocket Co.
        Conditions:
         Outlet Pressure  -  1000 PSIG

         Suction
         Condition - 8 PSI  Min.N.P.S.H.

         Fluid Temp  - 160-250° F
O System Max. Flow -
   Low Speed Corner Requirement
           20
                                                  28  GPM=1007.
                                                  8 GPM
                                                         4 GPMX
                          30     40      50     60      70
                          PUMP & EXPANDER SPEED -- PER CENT
80
                100

                90

                80

                70

                60

                50

                40

                30

                20
                                                                                z
                                                                                w
                                                                        707.
                                                                        Mech.
                                                                        EFF.


                                                                        507«
                                                                        Mech.
                                                                        EFF.
90
                                                                           100
0
0
200
3.1
400
6.2
600 800 1000 1200 1400
PUMP SPEED ^ RPM
9^4 12.5" is'. 6 18.6 2l'.8
EXPANDER SPEED x 10.3"^-RPM
1600
25.0
1800
2000
28.1 31.2
FIGURE 10
                                                                                   36

-------
                    AEROJET LIQUID ROCKET COMPANY

                         PUMP INLET ENVELOPE
TECHNICAL REQUIREMENTS

     1.  Inlet Pressure  The minimum pressure at the pump inlet valve
         during start-up may be as low as 1.0 psia.  During system
         operation, the inlet pressure may vary from a minimum of 10 psia
         to a maximum of 40 psia.

     2.  Net Positive Suction Head  The minimum liquid head at the pump
         inlet is 7 inches.  Care must be taken to assure cavitation  does
         not occur during start-up or during abnormal operating conditions
         resulting in a loss of condenser sub-cooling.

     3.  Temperature Range   During system operation, the temperature of
         the working fluid may vary from 160°F to 250°F.   At start-up the
         temperature of the working fluid may vary from -40°F to 275°F.

     4.  Booster Pump  A booster pump for providing the required net
         positive suction head to the feedpump shall be considered only
         if trade-off studies conducted by the contractor reveal that the
         utilization of a boost pump will simplify the feedpump design
         sufficiently to offset the additional cost, weight,and power
         consumption required by the boost pump.
TECHNICAL APPROACH

     The estimated pump inlet envelope on the following page shows the
Lear pump capability while operating at the 85% to 90% volumetric
efficiency level.  The N.P.S.H. values shown are taken from actual data
which has been corrected to meet the system contractors fluid character-
istics.


RECOMMENDATIONS

     Due to the inherent lower N.P.S.H. characteristics of a centrifugal
pump and its ability to handle large quantities of entrained vapor, a
separate centrifugal boost pump is recommended for this system.   The size
and characteristics of this pump will require a trade-off study  of the
systems condenser capability and the amount of sub-cooling allowable
before significant decreases in cycle efficiency occur.
                                                 LEAR MOTORS CORPORATION 	

                                                                            37

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               114.7

               104.7-


                94.7-


                84.7-
100


 90


 80


 70


 60


 50


 40
ESTIMATED FEED PUMP INLET ENVELOPE

  Fluid- AEF-78
Specific Gravity = 1.793 @72°F
System Contractor - Aerojet Liquid Rocket Co.
                                                                                        Open Pot Boiling Point
                                                                                        For AEF-78
                                                                                        (14.7 PSIA @ 189°F)
                             -20   0    20    40   60   80   100   120   140  160  180  200  220  240  260  280  300
                                                                 TEMPERATURE °F
CO
Co

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                     AEROJET LIQUID ROCKET COMPANY

                        PUMP DRIVE AND CONTROL
TECHNICAL REQUIREMENTS

     1.  Drive Mechanism  The feedpump shall be mechanically driven with
         power taken from the expander shaft or gearbox.  The feedpump
         shall provide the total range of required flow and pressure with
         the expander operation at any speed within-its specified speed
         range.  The non-linear relationship between expander speed and
         required feedpump flow and pressure shall be accommodated by
         variable drive mechanism characteristics and/or variable feedpump
         capacity characteristics.  The feedpump and drive mechanism should
         be capable of being mounted in the power plant as required by the
         system contractor.

     2.  Control  Movement of the vehicle accelerator pedal will provide
         a mechanical input signal to the feedpump for flow modulation.
TECHNICAL APPROACH

     An outline drawing of the proposed Lear Motors pump is shown on the
following page.  The pump has variable displacement capability and can be
directly driven by the expander.  Pump to expander speed ratio and
interface are not firm and will have to be worked out between Lear Motors
and the system contractor.

     Pump physical size is based on the contract pump performance require-
ments, i.e. flow rate, and any change in the design flow rate will directly
affect pump physical size and weight.
                                                 LEAR MOTORS CORPORATION 	

                                                                            39

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O

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                     AEROJET LIQUID ROCKET COMPANY

                        GENERAL REQUIREMENTS
TECHNICAL REQUIREMENTS

     1.  Vehicle Design Goals  Where applicable, "Vehicle Design Goals-
         Six Passenger Automobile", shall be used as a guide for the
         design requirements.

     2.  Leakage  There shall be no external leakage from the feedpump
         and its drive mechanism.  The unit shall be capable of being
         hermetically sealed.

     3.  Lubrication  Any lubricants that may be used within the feedpump
         and its drive mechanism shall not mix or contaminate the
         working fluid.  The lubricant shall be the same as that used in
         the expander.

     4.  Materials Compatibility  All  materials utilized in the construction
         of the feedpump shall  not corrode or otherwise chemically react
         with the fluid in any manner.
TECHNICAL APPROACH

     The Lear Motors pump design with its flexible diaphragm seal  provides
inherent hermetic sealing of working fluid from the air and lubricated
section of the pump.

     Materials used for the construction of the proposed ALRC feedpump are
shown in Table 3.  The material  used for the pumps flexible sealing member
can be constructed from elastomers which meet the temperature requirements
and is compatible with the working fluid.
                                                  LEAR MOTORS CORPORATION
                                                                            41

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THERMO ELECTRON CORPORATION TECHNICAL REQUIREMENTS AND
             LEAR MOTORS CORP. APPROACH
            VAPOR GENERATOR FEEDPUMP
           FOR RANKINE CYCLE AUTOMOTIVE
                 PROPULSION SYSTEM
          EPA CONTRACT NUMBER 68-01-0437
                 DECEMBER 1972
                                         LEAR MOTORS CORPORATION  	
                                                                    42

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                     THERMO ELECTRON CORPORATION

                          PUMP PERFORMANCE
TECHNICAL REQUIREMENTS

     1.  Expander Speed Range  The operating speed range of the recipro-
         cating expander will vary from a minimum of 300 rpm to a maximum
         of 1800 rpm.

     2.  Flow  Flow range shall be from 0 to 17 gpm.  Maximum system flow
         (17 gpm) shall occur at 45 percent maximum expander speed.   The
         feedpump shall be capable of modulating upon command from the
         propulsion control  system to satisfy any flow condition within the
         operating range specified.

     3.  Discharge Pressure  The feedpump shall be capable of operating at
         a constant discharge pressure of 1000 psia while modulating flow
         over the range specified.  The discharge pressure shall be stable
         with no high frequency oscillations in excess of 25 psi.

     4.  Efficiency  The feedpump mechanical efficiency shall be 70% or
         greater over the flow range from 30% of maximum design flow to
         80% of maximum design flow.  The mechanical efficiency shall be
         50% or greater at 10% of maximum design flow.

     5.  Fluid  The working fluid will be a non-corrosive organic fluid
         with a density of approximately 80 lbs/ft3.
TECHNICAL APPROACH

     The estimated performance curves, on the following page, demonstrate
how the proposed LMC feedpump would meet the TECO technical  requirements
shown above.  This estimate was obtained by extrapolating actual  LMC
feedpump data.

     The maximum pressure ripple requirement is met by utilizing  an odd
number of cylinders which are sized so that the instantaneous total flow
of the pump for any given crank angle is as smooth as possible.

     Additional information regarding the LMC technical approach  to the
TECO feedpump performance requirements may be found in the technical
discussions section of this report.
                                                 LEAR MOTORS CORPORATION  	

                                                                            43

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                  20
                       30
  40      50      60

PUMP SPEED -' PER CENT
70
80
90
100
  40
  36


  32
s
PM
o
1
fa
Pu
a
CM
  28
  24
20
16
12
                     Full Displacement Mech.  EFF.
             ESTIMATED FEEDWATER PUMP PERFORMANCE
               EPA Contract No.  68-01 0437

       System  contractor  -  Thermo  Electron Corp.

          Conditions:

             Outlet Pressure .  .  . 1000 PSIG

             Suction Condition .  . 7 PSI Min, N.P.S.H.

             Fluid Temp	160-250°F
            O System Max. Flow -

               Low Speed Corner Requirement
                  20
                       30      40      50     60     "70

                      PUMP & EXPANDER SPEED <- Per Cent
                                80
              "90
                                                                            100


                                                                            90
                                                                                6-S

                                                                            80  I
                                                                               70
                                                                                  w
                                                                               60
                                                                                  fa
                                                                               50  w
                                                                               40
                                               30  2
                                                   a
                                                   w
                                               20  33
                                                                               10
                                                70%

                                                Mech.
                                                Eff


                                                507,
                                                Mech.

                                                Eff
              100
0

0


200

180


400

360


600

540


800 1000 1200
PUMP SPhclD ^ RPM
720 900 1000
EXPANDER SPEED ^ RPM

1400

1260


1600

1440


i
1800 2000

1620 1800

FIGURE 13
                                                                                   44

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                    THERMO ELECTRON CORPORATION

                        PUMP INLET ENVELOPE
TECHNICAL REQUIREMENTS

     1.  Inlet Pressure  In the Rankine cycle system, the feedpump inlet
         pressure is determined by the condensing pressure and the
         elevation of the pump relative to the condenser.  At system
         start-up, prior to the time when condenser pressure builds up due
         to heat load, the inlet pressure at the pump may be no greater
         than 0.5 psia.  During operation the inlet pressure may vary
         from a minimum of 5 psia to a maximum of 90 psia.

     2.  Net Positive Suction Head  The minimum liquid head at the pump
         inlet is 10 inches.  Care must be taken to assure cavitation does
         not occur during start-up or during abnormal operating conditions
         resulting in a loss of condenser sub-cooling.

     3.  Temperature Range  During system operation, the temperature of
         the working fluid may vary from 160°F to 250°F.  At start-up
         the temperature of the working fluid may vary from -40°F to 275°F.

     4.  Booster Pump  A booster pump for providing the required net
         positive suction head to the feedpump shall be considered only if
         utilization of a boost pump will simplify the feedpump design
         sufficiently to offset the additional cost, weight and power
         consumption required by the boost pump.
TECHNICAL APPROACH

     The estimated pump inlet envelope on the following page shows the
proposed LMC pump capability while operating at the 85% to 90% volumetric
efficiency level.  The N.P.S.H. values shown are taken from actual data
which has been corrected to meet the TECO organic fluid characteristics.

     Due to the inherent lower N.P.S.H. characteristics of a centrifugal
pump and its ability to handle large quantities of entrained vapor, a
separate centrifugal  boost pump is recommended for this system.  The size
and characteristics of this pump will  require a trade-off study of the
system condenser capability and the amount of sub-cooling allowable before
significant decreases in cycle efficiency occur.
                                                 LEAR MOTORS CORPORATION 	

                                                                            45

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114.7
104.7-
100
                                                                     Normalv
                                                                     Operating
                                                                     Range \
           ESTIMATED FEED  PUMP  INLET  ENVELOPE
             FLUID  - Trifluoroethanol
                       (Fluorinol-85
             SPECIFIC  GRAVITY =  1.368 @72~F
           SYSTEM CONTRACTOR - Thermo
                            Electron  Corp.
                                                                    Open Pot Boiling Point
                                                                    Fluorinol - 85
                                                                    (14.7 PSIA @ 166
              -20   0    20   40   60   80   100  120  140  160   180   200   220  240  260  28.0  300
                                                  TEMPERATURE -F

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                      THERMO ELECTRON CORPORATION

                         PUMP DRIVE AND CONTROL
TECHNICAL REQUIREMENTS

     1.  Drive Mechanism  The feedpump shall be mechanically driven with
         power taken from the expander shaft or gearbox.  The feedpump
         shall provide the total range of required flow and pressure with
         the expander operation at any speed within its specified speed
         range.  The non-linear relationship between expander speed and
         required feedpump flow and pressure shall be accommodated by
         variable drive mechanism characteristics and/or variable feedpump
         capacity characteristics.  The feedpump and drive mechanism should
         be capable of being mounted in the powerplant as required by the
         system contractor.

     2.  Control   Movement of the accelerator pedal will provide a
         mechanical input signal to the feedpump for flow modulation.
TECHNICAL APPROACH

     An outline drawing of the proposed Lear Motors pump is shown on the
following page.  The pump has variable displacement capability and can be
directly driven by the expander.  Pump to expander speed ratio and inter-
face are not firm and will have to be worked out between Lear Motors and
the system contractor.

     Pump physical size is based on the contracts pump performance
requirements, i.e. flow rate, and any change in the design flow rate will
directly affect pump physical size and weight.
                                                 LEAR MOTORS CORPORATION  	
                                                                            47

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00

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                    THERMO ELECTRON CORPORATION

                         GENERAL REQUIREMENTS
TECHNICAL REQUIREMENTS

     1.  Vehicle Design Goals  Where applicable "Vehicle Design Goals-
         Six Passenger Automobile", shall  be used as a guide for the
         design requirements.

     2.  Leakage  There shall be no external leakage from the feedpump
         and its drive mechanism.  The unit shall be capable of being
         hermetically sealed.

     3.  Lubrication  Any lubricants that may be used within the feedpump
         and its drive mechanism shall not mix with or contaminate the
         working fluid.  The lubricant shall be the same as that used in
         the expander.

     4.  Materials Compatibility  All  materials utilized in the
         construction of the feedpump shall not corrode or otherwise
         chemically react with the fluid in any manner.
TECHNICAL APPROACH

     The Lear Motors pumo design with its flexible diaphragm seal  provides
inherent hermetic sealing of working fluid from the air and lubricated
section of the pump.

     Materials used for the construction of the proposed TECO feedpump are
shown in Table 3.  The material  used for the pumps flexible sealing member
can be constructed from most elastomers which meet the temperature
requirements and is compatible with the working fluid.
                                                  LEAR MOTORS CORPORATION

                                                                             49

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V  CONCLUSION
        Based on the results of this study and the past experience of Lear
   Motors in the development of Rankine Cycle Automotive Propulsion Systems,
   a radial  piston, variable displacement feedpump design was selected to
   satisfy the requirements of the three Rankine Cycle System Contractors.
        The proposed feedpumps hermetically seal the working fluid from
   the atmosphere and lubricating oil  by utilization of a diaphragm seal.
   all of the highly stressed moving parts in the pump are oil  lubricated
   allowing conventional, low cost materials to be used throughout its
   construction.
        Three separate pumps were determined necessary because of the vast
   difference in system flow requirements.  Due to the high flow at low
   speed requirements of the two organic systems, these pumps will  be
   physically larger than the pump designed for the water base contractor.
        Ductile iron was selected as the material of construction for the
   pump housing.  A detailed stress analysis of an aluminum pump housing  as
   a means of reducing weight is recommended.   Also, any reduction  in the
   high flow - low speed requirement of the organic systems would allow a
   significant reduction in size and weight.
        Projected feedpump performance will  contribute to high cycle
   efficiency; full displacement mechanical  efficiencies from 85 to 90
   percent are feasible.
        It is recommended that an externally driven boost pump be used with
   the proposed feedpumps to assure reliable operation at all  system
   operating conditions.  A centrifugal  type boost pump was selected because
   of its capability for pumping at very low NPSH values.
        A major effort was directed toward finding elastimers which were
   compatible with the two organic fluids.  Several  candidates  were found
   acceptable for operation at 250° or lower.   Additional  investigations  are
   required  to determine the long term effects of the fluids on elastomers.
        The  Lear Motors proposed feedpumps will  satisfy the requirements
   of the three Rankine Cycle Automobile Power Systems with one exception;
                                                    LEAR MOTORS CORPORATION 	

                                                                               50

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the low flow - high speed region of the estimated pump performances
does not fully meet the system contractors mechanical efficiency
requirements.
     The knowledge gained from this study and the background stemming
from our four year feedpump development program are incorporated in
these proposed pump designs.  Reliable operation with a minimum develop-
ment time is assured as this basic type of pump has been well developed
in the Lear Motor Rankine Cycle Systems.
                                                 LEAR MOTORS CORPORATION  	
                                                                            51

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                                REFERENCES
Baumeister, Theodore and Lionel S. Marks, ed., Mechanical Engineer's
     Handbook, New York:  McGraw-Hill, 1958.

Binder, R.C., Fluid Mechanics, Englewood Cliffs, New Jersey:
     Prentice-Hall, 1955.

Erast, Walter, Oil Hydraulic Power and Its Industrial Applications,
     New York:  McGraw-Hill, 1960.

Gartmann, Hans, ed., Del-aval Engineering Handbook, New York:
     McGraw-Hill, 1970.

Tuve, G.L. and L.C. Domholdt, Engineering Experimentation, New York:
     McGraw-Hill, 1966.
                                                  LEAR MOTORS CORPORATION 	

                                                                             52

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       APPENDIX A
LEAR MOTORS PUMP STANDARDS
                           LEAR MOTORS CORPORATION  	



                                                       53

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                                                       7001-3401
                                                       July 26, 1972
                             PUMP STANDARDS
                        LEAR  MOTORS  CORPORATION
PUMP TEST CODE
I.   Object
          This code establishes a procedure for conducting and
     reporting tests of Rankine Cycle feedwater and condensate
     pumps. It is intended that the tests shall be made and reported
     by qualified personnel trained in the proper application and
     use of the various instruments and methods involved.

II.  Records

          Complete records shal'l be kept of all information relevant
     to a test.  The serial number, type, size, or other means of
     identification of each pump tested shall be recorded in order
     that mistakes in identity be avoided.

III. Measurements

          The essential measurements for test of feedwater and
     condensate pumps are:

     1.   Flow
     2.   Outlet Pressure
     3.   Suction Pressure or Vacuum
     4.   Temperature of pumped fluid
     5.   Temperature of pump
     6.   Power input to pump
     7.   Speed
                                                  LEAR MOTORS CORPORATION
                                                                           A-l

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IV.   Flow Measurement

          The rate of flow shall be expressed in gallons per minute
     (gpm) and be measured with calibrated rotameter compatible
     with pumped fluid.

V.   Outlet Pressure Measurement

          Head or outlet pressure shall be designated in pounds per
     square inch gage (psig).  Measurement will  be made with a
     calibrate pressure gage of the proper range.

VI.   Suction Pressure or Vacuum Measurement

          Suction pressure shall be designated in pounds per
     square inch absolute (psia).  Suction vacuum conditions shall
     be designated in inches of mercury (in. Hq).  Measurement will
     be made with a calibrated pressure gage or mercury manometer
     of the proper range.

VII. Temperature Measurements

          Temperature will be expressed in degrees fahrenheit (°F).
     A calibrated thermometer with the proper range will be used.

VIII.Input Power Measurements

     (a)  Pump input horsepower may be determined by means of
     transmission dynamometers, torsion dynamometers or calibrated
     drivers.

     (b)  Transmission Dynamometers.  When pump input horsepower
     is to be determined by transmission dynamometers, the unloaded
     and unlocked dynamometer must be properly balanced prior to
     the test at the same speed at which the test is to be run and
     the scales should be checked against standard weights.  After
     the test, the balance must be rechecked to assure that no change
                                                 LEAR MOTORS CORPORATION 	
                                                                          A-2

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(b)  Cont.
has taken place.  In the event of an appreciable change,
the test shall be rerun.  An accurate measurement of speed is
essential.

(c)  Torsion Dynamometers.  When pump input horsepower is to
be determined by torsion dynamometers, the unloaded dynamometer
shall be statically calibrated prior to the test by measuring
the angular deflection for a given torque, the tare reading
on the dynamometer scale being taken at rated speed with the
pump disconnected.  After the test, the calibrations must be
rechecked to assure that no change has taken place.  In the event
of an appreciable change, the test shall be rerun.  An accurate
measurement'of speed is essential.

(d)  Calibrated Drivers.  When pump input horsepower is to be
determined by the use of a calibrated motor, the following shall
be applied:

1.   All measurements of power input shall be made at the
     terminals of the motor to exclude any line losses that may
     occur between the switchboard and the driver itself.
     Certified calibration curves of the motor must be obtained.
     The calibration shall be conducted on the specific motor
     in question, and not on an identical machine.

2.   Such calibration curves must indicate the true input-
     output value of motor efficiency and not some conventional
     method of determinining an arbitrary efficiency.

3.   When the pump is arranged with a speed changing device
     between the driver and the pump, the input to the pump
     shall be the actual output of the driving element less the
     loss through the speed changing device.  The value of
     this loss shall be certified by the manufacturer of the
     speed changing device.
                                            LEAR MOTORS CORPORATION  	
                                                                       A-3

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X.    Measurement of Speed

     (a)  Measurement of speed shall  be made by means of revolution
     counters or tachometers.

     (b)  For speed measurements taken by means of a revolution
     counter, the timing period shall  be of sufficient length to
     obtain a true average speed and  the stopwatch used should be
     checked against a standard timer.

     (c)  When a tachometer is used,  it shall  be calibrated against
     a revolution counter before and  after test.  Tachometer readings
     should be made at frequent intervals during each test point to
     obtain an accurate measurement of average speed over the reading
     period.
                                                 LEAR MOTORS CORPORATION 	
                                                                           A-4

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PUMP RATING CRITERIA

I.   Introduction

          The following numbered paragraphs define the quantities
     used to designate pumping applications.

II.  Volume, Standard Units

     (a)  The standard unit of volume shall be the United States
     gallon or the cubic foot.  The standard U.S. gallon contains
     231.0 cubic inches.  One cubic foot equals 7.4805 gallons.

     (b)  The rate of flow shall be expressed in gallons per minute
     (gpm), gallons per hour (gph).

     (c)  The specific weight of water at a temperature of 68°F
     shall be taken as 62.3 Ib per cu ft.  For other temperatures,
     proper specific weight corrections should be made.
III. Pump Volumetric Efficiency (Symbol E )
          The volumetric efficiency of a rotary pump is the ratio of
     the actual pump capacity to the displacement, expressed in percent,
     at the specified pumping conditions:

                       F  =   capacity   „ lnn
                        v   displacement

IV.   Pump Input (Symbol  bhp or ehp)

          The unit of power input to pump is the horsepower.

          1  horsepower = 550 foot-pounds per second
                       = 33,000 foot-pounds per minute
                       = 2545 Btu per hour
                       = .7457 kilowatts
                                                 LEAR MOTORS CORPORATION  	

                                                                           A-5

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     (a)  The input horsepower (bhp) when measured by a transmission
     or torsion dynamometer, is calculated from the following
     formula:

                          bhp =    2 *
                                   33,000

     where
          L = length of lever arm in feet
          W = net weight in pounds
          N = speed in rpm
          IT = 3.1416

     (b)  The electrical horsepower input to an electric motor is
     given by:

                           ehp = 	kw^Qr Volts X Amps
     where
          kw = kilowatt input.

     (c)  The input horsepower to a pump driven by an electric
     motor is:
                            bhp = ehp X Em
     where
          E  = true efficiency of motor.

V.   Pump Output (Symbol whp)

     (a)  Pump output is the liquid horsepower delivered by the pump.

     (b)  The liquid horsepower is to be computed by the following
     formula:
                                                 LEAR MOTORS CORPORATION  	

                                                                           A-6

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                     pounds of liquid  x  Total head in
               U(hn _ pumped per min.	ft of liquid
               W P            33,000
     (c)  If the capacity is expressed in gallons per minute (gpm)
     the formula for liquid horsepower becomes:

               ,,hn   gpm X (total head in feet) X sp gr
               wnp "            3960
     where:
          sp gr = specific gravity of liquid referred to 68°F water,
                  weighing 62.3 Ib per cu ft.

     (d)  If the total head is expressed in pounds per square inch,
     the formula for liquid horsepower, irrespective of specific
     gravity of the liquid, becomes:
               whp = gpm X (total head in psi)
                            17T4
VI.  Mechanical Efficiency

     (a)  Pump mechanical efficiency (E ) is the ratio of the energy
     delivered by  the pump to the energy supplied to the pump
     shaft; that is, the ratio of the liquid horsepower to the brake
     horsepower expressed in percent:

                                        100  or   whP _
                                        IUU  or
                                                     _
                             p   bhp           ehp X Em

     (b)  Overall  unit efficiency (EQ) is the ratio of the energy
     delivered by  the pump to the energy supplied to the input side
     of the pump driver; that is, in the case of electric-driven
     pumps, the ratio of the liquid horsepower to the electrical
     horsepower input to the driver, expressed in percent:
                            E, •
                                                 LEAR MOTORS CORPORATION 	

                                                                            A-7

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VII.  NPSH Definition

          NPSH (net positive suction head)  is defined as the net
     pressure absolute above vapor pressure at the pump inlet.   In
     pumping .liquids we are concerned with  getting the liquid into
     the pump in a liquid state (i.e. without vaporization).
     Suction lift, friction losses,  and entrance losses all  conspire
     to reduce net pressure and in some cases interfere with the
     liquid  getting into the pump  in liquid phase.

     It should be remembered that  the boiling ooint of a liquid  is
     that point at which vapor  pressure equals  external  pressure.
     Whether this takes  place in   open  or closed  vessels there is
     usually a vapor area in contact with the liquid  and a liquid
     level line.   At boiling point the  addition  of  heat or the lowering
     of external  pressure unbalances  this equilibrium  and results
     in the  vaporization of an  amount of liquid.

         Also  to be  considered is that centrifugal pumps are liquid
     handling  machines.   Although  pumps will  handle up  to 50%
     entrained  gas  or  vapor and will  dispose  of the air  in suction
     lines during priming  cycle they  are not  efficient  vapor handling
     devices.   Further,there  is a  great expansion of volume in the
     conversion  from  liquid  to vapor  state which  takes  up the
     inherent  pump  capacity.

         Reduced capacity  at low  NPSH  is an  efficiency  loss permitting
     no  revision  of  brake  horsepower.   Because of this'major
     consideration of maintaining  liquid state during the pumping
     cycle it  is  essential  to make an NPSH calculation  in all
     applications involving a liquid at or close to boiling point.
                                                LEAR MOTORS CORPORATION
                                                                          A-8

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NPSH CALCULATION
     Three general cases may be considered in making an NPSH
calculation.

Case I - The liquid level of the supply is above the pump
centerline.  This is termed static suction head.
Case II- The liquid level of the supply is below the pump
centerline.  This is suction lift.
     Case I is by far the most common in industrial applications.
Hot water or various other liquids are pumped out of a vessel
elevated above the pump.  In such a case it is usually necessary
to consider only four elements in calculating NPSH.
                           CASE I
               Fluid Level
       Direction
       Of Flow
WHERE:
hs = Static Suction Head (PSIG)
h  = Vapor Pressure (PSIA)
ha = Atmospheric Pressure (PSIA)
hf = Friction Loss (PSIG)
     In the range of capacities involving pumps (up to 250 GPM)
velocity head need not be considered.

     Then in any Case I system the following formula applies:

                    hs + ha - (hvp + M  = NPSH
                                             LEAR MOTORS CORPORATION
                                                                       A-9

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Case IA:  The liquid is in a closed vessel  in vacuum or pressure
systems.  In this special  case vapor pressure will  equal  atmo-
spheric pressure.
                            CASE IA
       Vent
      Direction
      Of Flow
                                    WHERE:
                                        = Static Suction Head (PSIG)
                                        = Vapor Pressure (PSIA)
                                    h,  = Atmospheric Pressure (PSIA)
                                     a
                                    hf  = Friction Loss (PSIG)
       vp
                          .'.  hs - hf = NPSH

In planning piping for NPSH  problems it is usually desirable to
increase the size of suction  piping until  friction loss in the
suction line is less than 6  in. of liquid  head.

In such cases h-r may be disregarded in the application.  The
formulae then becomes:
Case I:
Case IA:
ha - hvp = NPSH
hs = NPSH
In Case I NPSH is identical with static suction head when the liquid
is at boiling point and the suction piping is large enough to keep
total friction loss below 6 in. of liquid head.
                                             LEAR MOTORS CORPORATION
                                                                      A-10

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   Case  II can never  involve liquids at boiling point since a
   negative NPSH condition would result and vaporization would
   take  place.  All cases of NPSH calculations involving suction
   lift  must also  involve liquids below boiling point.  With the
   vapor pressure  less than the atmospheric pressure the formula is
   as follows:
                                CASE II
                   Discharge
          Direction
          of f1ow
—i-iii^^j— LI-— /—Foot Valve
                                      WHERE:
    = Static Suction Head (PSIG)
    = Vapor Pressure (PSIA)
ha  = Atmospheric Pressure (PSIA)
 .  = Friction Loss (PSIG)
vp
                           ha  ' hvp  - hs ' NPSH
   Atmospheric pressure  is  then the only positive force in Case II
   Both vapor pressure and  suction lift are negative factors.
   NOTE:
        Static suction head  (h ) for any fluid:
        Inches of Head x Specific Gravity x .03613 = PSIG
        Feet of Head x Specific Gravity x .4335 = PSIG
     K*
Max K. Winkler
                           Reference:  Standard of Hydraulic Inst.
                          	 LEAR MOTORS CORPORATION
                                                                         A-ll

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