MEASUREMENT OF PRESSURE DROPS ACROSS STANDARD PIPE AND FITTINGS

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A002800020001-9
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 73
• Document Creation Date: December 28, 2016
• Document Release Date: August 28, 2002
• Sequence Number: 1
• Publication Date: February 1, 1965
• Content Type: REPORT

STATOTHR
~ Approved For Release 2002/09/03 :CIA-RDP78B04747A002800020001-9
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 Approved For Release 2002/09/03 :CIA-RDP78B04747A002800020001-9
REPORT
MEASUREMENT OF PRESSURE DROPS
ACROSS STANDARD PIPE AND FITTINGS
STATOTHR
RM-133-65
February 1965
STAT
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TABLE OF CONTENTS
Section
Page
1
Introduction
I- I
1. 1
Data Limitations
1-1
1.2
Purpose and Objectives
1-1
2
Technical Discussion
2 -1
2. 1
Equipment and Instrumentation
2-1
2. 2
Pressure Drop Experimentation
2 -2
3
Conclusions
3-1
3. 1
Pump Tests
3-1
3. 2
Pressure Drop Tests
3-2
4
Recommendations
4-1
4. 1
Continued Experimentation
~4-I
References
Appendices
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Frontispiece
LIST OF ILLUSTRATIONS
Page
Figure 2-1
Pressure Drop Test Apparatus 2-35
2-2
Test Rack =Pump, Gage, Manometer, and Fiowmeter 2-37
2-3
Test Rack -Pump, Gage, Manometer, and Thermometers 2-38
2-4
Test Rack Apparatus and Inclined Manometer 2-39
2-S
Flowmeter Calibration Chart 2-41
2-6
Reynolds Numbers vs. Frlction Coefficients 2-43
2-7
~ p's for 90-Degree Elbows 2-45
2-8
~~t's for 90=Degree Elbows 2-46
2=9
hp's far Tees 2-47
2-10
Lip for PVC Union 2-48
2-11
~,p for PVC Tee 2-49
2-I2
,~~'s for 90-Degree PVC Elbows 2-50
2-13
Dimensions of Sweep Elbows 2-51
2-14
?hp's for 45-Degree PVC Elbows 2-52
2-15
L1p for PVC Bali Valve 2-53
2-i6
~p for PVC "Y" Valve 2-54
2=17
Lip for PVC Plug Valve 2-55
2-1$
~p for PVC Coupling 2-56
2-19
Qp for PVC Pipe and Fittings 2-57
2-20
Fairing Tool 2-58
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STAT
.r
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STATOTHR
submits this report in compliance with Item 3. 4 of the
Development Objectives of
in conjunction with Report
This report should be read
of which it forms part.
STATOTHR
Approved:
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ABSTRACT
Pressure drops were measured and recorded, tabularly and
graphically, for various polyvinyl chloride fittings and straight pipe,
both before and after reaming and fairing all internal protrusions. All
mensuration equipment was described in detail and calibration data were
included. Numerous tests and calculations were performed on the pump
to check its operation. Recommendations for further research, in the
light of present findings, are appended.
vi
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 STATOTHR
1. 1 DATA LIMITATIONS
When the liquid bearing concept was first considered, the state-
of-the-art in processor design required only the movement of film through
the various steps of developing and fixing by means of rollers or sprockets.
Hydrodynamic and fluid mechanic complexities introduced by the new STATOTHR
bearing, in which the film was supported on a liquid cushion, required
engineers to depend heavily on available technical data -pump
capacities, pipe and fitting losses, pressure drops through filters, and
frictional coefficient buildup with photochemical deposits. Inadequacies
in the published data parameters quickly became apparent when pump ca-
pacities had to be virtually doubled to compensate for line losses, even
though supposedly ample design safety factors had been incorporated.
1. 2 PURPOSE AND OBJECTIVES
One of the foremost objectives of the assignment was to satisfy
the need for these missing parameters and provide, generally, amore complete
technical documentation of fundamental engineering data germane to pro-
cessor design. One important byproduct of the research program, then,
was to eliminate rule-of-thumb calculations in which the pressure drop in
a 45-degree elbow was assumed to be one-half of that fora 90-degree
elbow, or that in a valve four times a 90-degree elbow, with a safety fac-
tor of 2 0 percent or better.
With the shortcomings of technical literature in mind, the objec-
tives of the research project were formulated. The following list com-
prises the most important research objectives for this part of the pro-
gram;
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1) Check as many different fittings (including straight pipe) as
feasible in the light of time and budget.
2) Begin experimentation on 1-1/4-inch rigid polyvinyl chloride
(PVC) pipe and threaded fittings. Measure ~p with unburned fittings and
pipe. Repeat tests with burred fittings and internal taper.
3) Repeat tests outlined in objective (2) with socket-type fittings.
4) Repeat the series of tests with polished, sanitary stainless
steel dairy pipe and fittings.
5) Determine the effect of pump inlet pipe size.
6) Determine the effect of restricted inlet pipe size.
7) Study input of pump, mechanical efficiency, losses, and the
effect of a dropping head on pump output.
8) Make a long run breakdown test of pump, using actual photo-
graphic chemical solutions.
9)~ Check the interrelationship of pump outlet angle on delivered gpm.
10) Make effectivity comparisons among various types of flowmeters
- rotameter, orifices, venturi, and newer types.
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2. 1 EQUIPMENT AND INSTRUMENTATION
The pressure drop test apparatus is illustrated in Figures 2-1,
STATOTHR2-2, 2-3, and 2-4. All instrumentation and fittings are described in detail
`~ in Appendix F. A stainless-steel hold tank, on loan from
formed the core of the circulatory setup. From its center bottom outlet,
a 2-inch ID PVC pipe fed a 2-horsepower centrifugal pump.
On both the inlet and outlet sides of the pump, thermometer wells
were provided for measuring T1 and T2 respectively. Unions were installed
on b?th sides to enable easy removal of the unit without disturbing the rest
of the apparatus. On the downstream side, a valved tee for drainage and a
pressure gage to read P 1 were provided. The piping then led directly to a
1-1/4-inch ball throttling valve and the flowmeter, and from the latter to the
remaining test apparatus. The test piping and fittings were all 1-1/4-inch
PVC, with the exceptions noted (Appendix F). They were supported on two
tiers by wooden racks.
The lower level was a straight run of pipe over 10 feet long; a riser
led to the upper level and to a union leading to a tee. The left branch of
the tee was arbitrarily designated Branch I and the right, Branch II. Each
of these two branches returned to the hold tank. Branch I embodied three
test fittings and Branch II, four. The wooden supporting racks were care-
fully leveled so that both the upper and lower stages were precisely hori-
zontal. Each fitting was provided with an upstream and downstream pressure
tap for ~p measurement. These consisted of holes drilled and tapped for
1/8-inch standard pipe thread. The tapping depth was controlled so that
when the flanged brass tubing adapters were screwed in, their bottoms
would be flush with the inside of the pipe in accordance with Hydraulic
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Institute Standards (Ref: 11). The test apparatus was completely assembled
from a scale drawing by two shop plumbers. The only specific instruction
given them was to use standard shop practice in cutting, fitting, and thread-
ing pipe and to use "Proseal" (flexible two-component epoxy mixture) in
making up the joints. The completed test rack closely approximated the
STATOTHRassembly technique incorporated in any standard
All pressure drops were measured with either a vertical U-tube
manometer or a sensitive inclined mercury manometer. The tank temperature,
T3, was measured with an accurate Centigrade thermometer.
2. 2 PRESSURE DROP EXPERIMENTATION
The first step in the research project was the calibration of the
flowmeter. This was done by accurately timing, with a stopwatch, the
filling of a standard bucket whose exact capacity had been measured,
Enough runs were made at each 2 gpm flow increment on the rotameter scale
to assure 'an accurate mean average. The data are presented graphically
in Figure 2-5 and tabularly in Table 2-1, Based on the same data, the
Reynolds numbers were calculated and plotted against friction coefficients
(both are dimensionless) for PVC pipe (Figure 2-6), The data for various
commercial pipes and tubes were obtained from the literature (References
1 and 2), Tt is interesting to note how much less the coefficients of friction
are for plastic than for glass, supposedly the epitome of smoothness.
The pressure drops and Reynolds numbers were measured on the
horizontal 10. 020-foot section of the 1-1/4-inch PVC pipe (lower level).
So that the total pressure drop for the section could be .measured simul-
taneously, along 1/4-inch diameter copper tube was connected to the up-
stream pressure tap and brought to the downstream end. When all lines
were bled free of air, the readings were taken on the inclined mercury
manometer.
2-2
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Time, rate of flow, temperature, inlet pressure, and pressure drop
were recorded in a typical series of tests. The flow was changed from
maximum to minimum rotameter readings in S gpm increments. Enough rechecks
were made to assure reproducibility of readings. As the tests progressed,
it was found better practice to proceed from the lowest to the highest flaw
reading. Use of this technique resulted in less overall temperature var-
iation (since the tank was nonadiabatic} for a series which might take as
long as 26 minutes. Corrections for density, viscosity, etc. , with temper-
ature were made in the observed results (Appendix A).
Since the accurate calorimetric thermometers used were of the total
immersion type, stem temperatures were recorded during the early runs. A
sample calculation (Appendix B) showed the stem correction to be negligible
in the 69o to 77oF ambient operating temperature range used, so it was
neglected.
Pressure drops on the 1-1/4-inch tee were recorded across each leg
independently, with the opposite leg blocked off, and again with both legs
open. Data obtained for pressure drops with both legs of the tee open were
omitted because their intervariation was slight and in all cases, the readings
were less than those with one leg blocked off. Since design would be based
on maximums, these data lost their significance. Note that the pressure
drops across the leg leading to Branch II were higher than those leading to
Branch I. Two explanations are passible: 1) An Internal aberration in the
plastic die not removed by the burring operation was responsible, or Z) The
increased pressure drop in Branch II (in all cases higher than Branch I)
was reflected back to the leg of the tee.
in only three instances could comparable data be found in published
charts, those for straight pipe, a 90-degree elbow, and a tee. These are
presented, together with our data, in Figures 2-7, 2-8, and 2-9. Some of
the proprietary data seems overly optimistic. Note that the
STATOTHR
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data is not exactly comparable, since the closest size to our 1-1/4-inch
TD pipe is their 1.402-inch stainless.
The remaining data are presented graphically in Figures 2-10 through
2-19 and tabularly in Tables 2-2 through 2-20. Each set of data presents
a comparison between pressure drops in the fittings with unreamed pipe and
with reamed pipe. The latter data were obtained in the following manner.
After all tests were made on the original setup, the components were carefully
identified and'the apparatus completely disassembled. All fittings were
internally deburred and each end of the connecting pipes faired with a special
tool (Figure 2-20). The apparatus was then reassembled with Proseal in
exactly the original order and orientation. With no other change, the flow
was increased 6. 7 percent. This result points to possible economies
in reduced pump sizing on large production machines.
When the test apparatus was first assembled, a source of sweep
fittings to check against the common, standard pipe thread, short-turn
types could not be located, Continued market research uncovered a line
of specialized electrical conduit fittings manufactured by ~ The tests
STATOTHR
were subsequently performed on two of these PVC Schedule 40 conduit turns
(Figure 2-13) fitted with female adapters, slip to thread. The pressure drops
in the 90-degree sweep elbow (Figure 2-12 and Table 2-14) were almost
?r
exactly equal tv those of a straight pipe of equivalent length. In neither the
case of the 45-degree sweep nor that of the short-turn elbow were the pressure
drops half of those of the 90-degree elbow. They were more. This phen-
omenon cannot be explained by inaccuracies of mensuration (see discussion
of errors, Appendix C). The appendix also includes calculations of pump
heads and effect of discharge angle on delivery.
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TA6LE 2-I
FLOWMETER CALIBRATION DATA AND REYNOLDS NUMBER CAL CULATION
Flowmeter
Reading
gpm
Measured'
Flaw
gpm
~
~ 2
o F
P
qm/ml
g
ft ,/sec
V
ft/sec
2
1/V
sect/ft2
f
u
lb/ft sec
1/?
~ ft. sec./lb
o 3
lb./ft
R
e
41.2
40.8
71.05
.99720
.0893
10.36
.00932
.00218
.000608
1645
62.25
1.11 x 105
39.6
40.8
72.55
37,7
38.2
72.75
.99718
.0833
9.66
.01072
.00214
.000607
1649
62.25
1.04 x 105
35.8
38.2
72.85
33.9
33.8
72,95
.99716
.0724
8.40
.01417
.00215
.000606
1651
62.25
9.05 x 104
32.1.
31.2
72.45
30.2
29.6
72.55
28.3
26.9
72.65
.99716
.061$
7.17
.01945
.00228
.000605
1652
62.25
7.73 x 104
6.3
26.3
72.70
24.4
23.7
72.85
22.5
21.5
72.90
,99714
.0509
5,90
.02673
.40349
.000605
1654
62.25
6.37 x 104
6
19.7
73.00
1a.7
18.2
73.10
.99713
.0400
4.64
.04645
,00259
.000604
1655
62.25
5.01 x 104
16.7
15.8
73.20
14.7
13.9
73.30
.99712
.0291
3.38
.08754
.00315
.000603
1657
62.25 .
3.65 x 104
12.8 ~
11.1
73.45
10.9
10.3
73.50
9.
7.9
73.55
.99710
.0182
2.11
.2246
.00332
.000603
1660
62,25
2.29 x 104
6.9
7.2
73.65
4.9
4.5
73.75
-
2.6
74,05
.99706
.0071
,823
1.476
.00417
.0 6
8.95 x 1 3
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 Meter Flow
Carrected
~~~
TZ
of
P1
psi
40.6
41.1
76.08
~ 13.9
3707
37,7
76.21
14.4
0
3 6
6.32
15.1
28.3
27.8
76.39.
15.7
23.5
22.9
26.45
.16.2
76.S6
I~.7
76.62
17.3
?0
8.8
76.76
17.8
401
4.1
77.06
1$.3
41.Z
76.65
13.9
2.88
Total/2
3.32
2.84
2.15
1.66
.79
.21
3,30
?Table 2-3
Head boss In Feet Of Water/100 Feet ?f 1>lf4-Inch FVC Pipe
(Rea~nsdj
~~?~
~g,a
70.30
13.6
.53
4 4
70.25
14.1
35.0
34.7
70.22
19,9
30.0
29.5
70,1
15.6
4
70.15
16.0
0 1
16.5
0
14,2
70.15
16.9
10.0
9.2
70.15
17.8
4.8
70.27
I8o2
4.07
3.29
Zero Low
054 4.25
3.78
3.00
2.44.
1.95
1.47
1.19'
.8 f.
4.28.
.03 3,57
3,12
2.43
Total
6.63
5.67
4.29
2.45
1.02
6.59
6.63
5.16
2.57 1.86 3.~7
2.00 1.43 2,87
1.48 .96~ 1.88
1.04 .59~ 1.07
~~ .32~ .50
.5_ 61 .13~ .13
3.32
2.58
Ft. Water
13.56
x -~- -1
3.48
2.97
1.74
1.29
3.46
4.00
3.48
2.70
Ft, Los
100' 100
'~
34.73
29.64
22.46
17.37
12.87
55.29
34.53
39.92
34.73
26.95
1.94 2.03 20.26
1.44 1051 15.0,7
.94 .98 9.78
.54 .57 5.69
.25 .26 2.S9
.07 .07 .70
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Table 2-2
Head Loss In Feet C?f Water/100 Feet 0# 1-1/4-Inch PVC Pipe
(Urtre~med)
Zero High
.03 2,98
1.86
1.45
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Meter Flow
gpm
Corrected
gpm
T2
?F
P1
psi
~
Zero Hig
Zero Low
Total
Total/2
t. Water.
x 13.56-1
Correction
Factor Ft,
s
Tap
Distance
Corrected
Reading Hd
40.5
41.0
70.33
13.8
.25 1.1
,09 .57
1.37
.69
,72
.0297
-.43
.29
35.0
39.7
70.35
14>6
.90
,50
1.06
.S3
.55
.0211
-,30
,25
30.0
29.5
70.42
15.4
.77
.43
.86
.43
.45
.0158
-,23
,22
20.0
19.3
70.55
16.6
>57
.38
~ .55
.2$
.29
.0082
-.12
.17
15.0
14.2
70.62
17.1
.47
,27
~ ,40
.20
.21
.0051
-.07
,14
10.0
9.2
70.67
17.6
,4
,23
' ,29
.15
.16
.0024
-.03
.13
5.0
4.8
70.69
18.1
.33
.23
.22
.11
,11
.0009
-.O1
,10
Table 2-5
Head Loss In Feet of WSter For 1-1/2" Rigid PVC Union
43.2
40.0
44.3
40.4
70,61
70.56
13.6
14.2
,50 1.48
1.37
.08 .S2
.43
1,42
1,22
.7l
.61
.74
,64
.0333
,0289
-.48
-.42
.26
,24
30,4
29.5
70.50
15,6
.98
.28
.68
.34
,36
.0169
-.24
,12
5
4
7 9
I6.0
.8S
.25
,52
.26
.2
! 1 6
20.0
9.3
70.40
16.7
.72
,19
.33
,17
.1$
.00816
-. 12
.06
15.0
14.2
70.40
17.1
.62
.16
.20
.10
.ll
.00475
-.07
,04
10,0
9.2
70.40
17,7
,55
,12
.09
>OS
.05
.00217
-,03
.02
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Table 2-4
Head Loss In Feet Of '~Nater For I-1~4" Rfgid PVC Union
(Unnamed Pipe
(Reamed Fipe)
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P3
Meter Flow
gpm
Corrected
gpm
T2
? F
P1
psi
~ ~
Zero High
~2
Zero Law
Total
Total/2
Ft. Wafer
x 13.56 -1
orrec on
Factor
Tab
T}jstance
.
Corrected
Reading Hd
Doss