EPA-670/4-74-007
October 1974
EVALUATION
OF THE
RYAN WATERPROOF THERMOGRAPH (MODEL F-30)
By
Richard P. Lauch
Methods Development and Quality Assurance Research Laboratory
Program Element 1HA327
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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REVIEW NOTICE
The National Environmental Research Center -- Cincinnati
has reviewed this report and approved its publication.
Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
11
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FOREWORD
Men and his environment must be protected from the adverse effects
of pesticides, radiation, noise and other forms of pollution, and the
unwise management of solid waste. Efforts to protect the environment
require a focus that recognizes the interplay between the components
of our physical environment--air, water, and land. The National Envi-
ronmental Research Centers provide this multidisciplinary focus through
programs engaged in
• studies on the effects of environmental
contaminants on man and the biosphere, and
• a search for ways to prevent contamina-
tion and to recycle valuable resources.
The Ryan Thermograph Temperature Recorder was evaluated at the re-
quest of the Cincinnati District, U. S. Corps of Engineers, in the
Instrumentation Development Laboratory, AQCL, NERC-Cincinnati. This
study included tests for accuracy, stability, linearity and response.
Other pertinent characteristics are discussed.
A. W. Breidenbach, Ph.D.
Director
National Environmental
Research Center, Cincinnati
111
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CONTENTS
Page
Synopsis 1
Stability of Thermagraph at Constant Conditions 1
Linearity 1
Response 2
Construction 3
Recording Device 3
Maintenance 4
Installation Problems 5
Summary 5
Conclusions 6
IV
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SYNOPSIS
The Ryan waterproof thermograph (Model F-30) was evaluated. The
evaluation included tests for stability, linearity, response time,
and accuracy. Recorder resolution, definition, and data pick-off
capabilities were observed. The thermograph's construction,
maintenance, and installation problems were discussed.
STABILITY OF THERMOGRAPH AT CONSTANT CONDITIONS
Stability tests were made at 35, 55, and 75F, respectively. First
the thermograph was calibrated at the 35F condition; then it was
fully immersed in a constant temperature bath under approximately
2 feet of water. A water pump provided thorough mixing throughout
the bath. A precision thermometer was strapped directly to the
thermograph's sensing bulb. The unit was left in the bath at each
temperature condition for two or more days. (Table 1)
35F Condition - The true bath temperature varied from 35.3 to
35.6F (Range = 0.3F). The Ryan thermograph chart read from
35.5 to 36.OF (Range = 0.5F). It was impossible to read the
Ryan instrument closer than 1/2F. The thermograph variation
was not significantly greater than the variation of the bath.
Therefore, stability at this condition was satisfactory.
55F Condition - The true bath temperature varied from 54.6 to
55.OF (Range = 0.4F). The thermograph chart read from 55.0
to 55.5F (Range = 0.5F). Since the thermograph variation was
not significantly greater than the bath variation, stability
at this condition was satisfactory.
75F Condition - The true bath temperature varied from 75.8 to
76.5F (Range = 0.7F). The thermograph varied from 77.0 to
77.5F (Range = 0.5F). The Ryan thermograph varied less than
the bath and therefore stability at this condition was satis-
factory.
LINEARITY
Temperature - Ryan temperature vs true temperature is plotted
in Figure 1. These are average readings taken from Table 1.
The graph indicates that Ryan temperature is linear with true
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temperature. The slope of the curve is slightly greater than
1. The calibration at 35F reflects the close agreement at
this condition. The curve points out the desirability of
calibrating the unit at mid-range. If this were done, better
agreement would be obtained at the high end point.
Time - Figure 2 shows that the chart travel is linear with
time. The initial step on the graph of 0.1 day for 0 inches
of chart travel probably reflects the initial take-up of the
chart on the spool (i.e., the chart did not move under the
scriber until the slack was taken up).
RESPONSE
Response time tests were made from mid-range to the end points
and vice versa. Results of these tests are given in Table 3.
Response was fairly rapid until the scriber reached a point that
was within 1 to 2F of the end point. At this point response
became slow. The initial intention was to log the response time
required for 98% of a step change. Sluggishness near the end
points and the inability to read the chart to 2% of a 20F change
made this extremely difficult. For these tests, response time
was defined as the period from initial immersion into a bath set
at 20F temperature differential, until noticeable movement of
the scriber ceased. In Table 3, average response time ranged
from 50.6 to 63.8 seconds.
The sluggishness made it desirable to perform additional tests
which would indicate hysteresis and dead band. (Figure 3 and 4)
Hysteresis data were obtained when only the instrument's sensing
bulb was in the constant temperature bath. The cover of the
instrument was left off so that the strip chart could be read.
The bath temperature was changed in 5F increments and the instru-
ment was read only after the bath temperature peaked and remained
constant for 5 minutes or more. The hysteresis curve is shown
in Figure 3.
In testing for dead band, the unit was first taken from a bath at
approximately 75F and placed in a bath that was held constant at
55.2F. The unit was left in this bath for 150 minutes. The pro-
cedure was repeated with the starting point set at approximately
35F. Figure 4 shows that when a central temperature (55.2F) was
approached from two ends (75 and 35F) , the differential was closed
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rapidly at first (to 2.5F in 1 to 2 minutes); it then took 150
minutes to close the differential to IF. Hence the dead band was
not greater than IF.
CONSTRUCTION
The instrument is very sturdy and well built. It is enclosed
inside a stainless steel shell and sealed in two places for pro-
tection from water leaks. One seal consists of an "0" ring that
is compressed by a girth clamp. The other seal consists of an "0"
ring with an application of a fine grade "0" ring lube. No leaks
occur in 2 feet of water. It appears that the instrument could be
submerged to much greater depths, as no large non-stainless steel
areas are exposed to the water. The manufacturer specifies that
the unit is waterproof to 1000 feet.
Complete construction details (including how it works) are given
in the manufacturer's specifications. A visual inspection of the
unit revealed these details.
RECORDING DEVICE
a. Resolution
The instrument uses chart paper that is 2 inches high and
covers a temperature differential of 60F. Therefore, IF
represents .033 inch on the chart. The chart is graduated
every 2 degrees. It is easy to read the chart to 1/2 of a
graduation. Estimates can be made to 1/4 of a graduation or
0.5F.
The Model F-30* has a recorder chart speed of 5/8 inch/day.
This is .026 inch/hour. Therefore, it is difficult to read
this chart at a specific time.
b. Definition
The strip chart is pressure sensitive and the scriber makes
a line that is clearly visible.
*Ryan thermograph Models F-8 and F-15 use chart speeds of 2-1/2
and 1-1/4 inch/day respectively.
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c. Accuracy
The manufacturer indicates a temperature accuracy that is
within 2%. Thus a full scale range of 60F is accurate within
+1.2F. (Refer to Table 2.) This table compares the average
Ryan temperature with the average true bath temperature for
each of the three conditions. The average differences between
Ryan and true temperature were 0.2, 0.5, and 1.2F at the 35,
55, and 75F conditions, respectively. None of the averages
differ from truth by more than 1.2F. Some of the individual
readings at the 75F condition differed from truth by slightly
more than 1.2F. If the unit was calibrated at mid-range in-
stead of at the 35F condition, there would have been better
agreementaat the high end point. Therefore, the thermograph
is accurate within ±2% of full scale.
The manufacturer indicates a time accuracy of 2%. Figure 2
shows that the chart drive is linear with time. The chart is
marked in increments of 2 days. These markings were checked
and they are accurate with the recorder movement. The manu-
facturer indicates a 5/8 inch/day chart travel for the Model
F-30. This was checked and found to be accurate within 2%.
d. Data Pick-off Capabilities
The chart for the Model F-30 can easily be read to IF. It
would be very difficult to read time in increments closer than
1 hour.
e. Other
The recorder mechanism, which is spring wound, ran continu-
ously for a 30-day period and time vs chart travel was
extremely linear throughout the period.
MAINTENANCE
The unit requires very little maintenance:
1. Change chart and rewind every 30 days.
2. Use "0" ring lube whenever cover is reinstalled.
3. Check calibration, at mid-range, before using the instru-
ment and adjust scriber arm if necessary.
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INSTALLATION PROBLEMS
a. Assembly
None
b. Field Installations
The instrument should include an eyebolt on top of the casing
so that it may be positively secured with a line before it is
lowered into the water.
SUMMARY
a. Stability
Satisfactory.
b- Linearity (temperature and time)
Satisfactory.
c. Response Time
Approximately 57.5 seconds for completion of 90% of a 20F step
change. Some hysteresis and dead band were noted.
d. Construction
Sturdy, corrosion resistant.
e. Resolution
Satisfactory for temperature. Difficult to read chart at
specific time.
f. Definition
Satisfactory.
g. Accuracy
±2% of full scale on temperature when properly calibrated.
Calibration is a tedious process. Chart travel is linear and
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the 2 day time markings are accurate but the (Model F-30)
chart would be difficult to read in time increments that are
closer than 1 hour.
h. Data Pick-off Capability
Temperature (to IF). Time (no closer than 1 hour for the
Model F-30).
i. Maintenance
Very little required.
g. Installation Problems
1. Assembly - none.
2. Field - provision should be made to enable one to
secure the instrument to a line.
CONCLUSIONS
Average instrument accuracy was within ±2% of full scale when cali-
brated properly. Accurate calibration is a tedious process. Some
hysteresis, dead band, and sluggishness near the end point of a
step response was noted. This is shown in the report and should
be carefully scrutinized by one contemplating purchase of the
instrument. Resolution is satisfactory for temperature, but it is
difficult to read the chart at a specific time. When properly
calibrated, the instrument is a useful tool for collecting tempera-
ture data with reasonable accuracy in remote stream locations for
unattended periods up to 30 days. Pinpoint accuracy, as required
of a precision thermometer, should not be expected.
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Table 3. RESPONSE TIME TESTS (12/27/68)
Avg. =
Avg. =
Note:
Avg. =
Avg. =
Low F
35
Low F
35
35
35
35
35
35
35
35
35
35
35
35
Response
was very
Low F
55.2
Low F
56
56
56
56
56
56
56
56
56
56
56
56
Bath temperature
Ryan temperature
High F
_ .
«, , CA
^
OH-
54
'
* "
"
» r-->
High F
54.6
Time (sees.)
50
60
55
58
30
50.6
54
70
60
75
60
52 63.8
from 52F to 54F on rising temperature
slow.
Bath temperature
Ryan temperature
High F
.• 7/1
™ / 4
— 77
•• ... 77
™ / J
73.2
A 717,
•* / o
» 77.
m 1 J
7'
7X
~~^^ I \J
73
High F
74.6
Time (sees.)
60
60
60
55
60
59.0
65
55
53
55
55
56.6
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75
—. 70
LU
o
uj 65
I- 60
£ 55
50
45
40
35
1-22 TO 1-24-69-*^
RYAN VS TRUE
1-24 TO 1-30-69
1-30 TO 2-3-69
35 40 45 50 55 60 65 70 75
TRUE TEMPERATURE (°F)
(TAKEN WITH PRECISION THERMOMETER)
FIGURE 1 TEMPERATURE LINEARITY
to
LU 12
I
U
Z 10
3 '
X
0 2
DATE
1968
12-13
12-16
12-17
12-23
12-24
12-27
12-30
12-30
TIME
DAYS
3.18
6.15
6.93
13.18
14.0
16.98
19.93
19.99
TRAVEL
IN.
1.96
3.85
4.33
8.37
8.88
10.82
1270
12.76
6 8 10 12 14 16
TIME (DAYS)
FIGURE 2 TIME LINEARITY
18 20
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2^ 75
ol
I 7°
< 65
* 60
Y 60 65 70 75
TRUE TEMP. (°F)
35 40 45 50
FIGURE 3 HYSTERESIS
{FROM 35° F)
-25
(FROM 75°F)
54.2 55.2
BATH HELD CONST.
AT THIS TEMP.
56.2
RYAN TEMP.
FIGURE 4 DEAD BAND
10
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FIGURE 5 - COPY OF
ORIGINAL STRIP CHART
(TIME LINEARITY, RESPONSE)
11
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•SF
d
p
JiiiUiU
I
If/
r j
FIGURE 6 - COPY OF
ORIGINAL STRIP CHART
(STABILITY, ACCURACY, TEMPERATURE LINEARITY,
HYSTERESIS, DEAD BAND)
12
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
. REPORT NO. 2.
EPA-670/4-74-007
. TITLE AND SUBTITLE
EVALUATION OF THE RYAN WATERPROOF THERMOGRAPH (MODEL
F-30)
. AUTHOR(S)
Richard P. Lauch
. PERFORMING ORGANIZATION NAME AND ADDRESS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
2. SPONSORING AGENCY NAME AND ADDRESS
Same as above
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
October 1974; Issuing Date
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
1HA327; ROAP 01AAD; TASK 03
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
5. SUPPLEMENTARY NOTES
5. ABSTRACT
The Ryan waterproof thermograph (Model F-30) was evaluated. The evaluation included
tests for stability, linearity, response time, and accuracy. Recorder resolution,
definition, and data pick-off capabilities were observed. The thermograph's
construction, maintenance, and installation problems were discussed.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
'emperature measuring instruments,
Txermal measurements .
DISTRIBUTION STATEMENT
Release to public
b. IDENTIFIERS/OPEN ENDED TERMS
Thermograph evaluation,
Temperature instrumenta-
tion, Thermograph
performance , Thermo-
graphs.
19. SECURITY CLASS (This Report)
UNCLASSIFIED
20. SECURITY CLASS (This page)
UNCLASSIFIED
iC. COSATI Field/Group
13B
21. NO. OF PAGES
17
22. PRICE
\ Form 2220-1 (9-73)
13
US SOVBHHKPffPIIIIITIIIS OFFICE 1974-657-051/1057
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