Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
IRRIGATION
TRAINING &
RESEARCH
CENTER
Low-Pressure Testing Pressure Regulating Valves
August 2013
TTeecchhnniiccaall RReeppoorrtt
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Prepared by Dr. Charles Burt Kyle Feist Irrigation Training & Research Center (ITRC) California Polytechnic State University San Luis Obispo, CA 93407-0730 805-756-2379 www.itrc.org
Disclaimer: Reference to any specific process, product or service by manufacturer, trade name, trademark or otherwise does not necessarily imply endorsement or recommendation of use by either California Polytechnic State University, the Irrigation Training & Research Center, or any other party mentioned in this document. No party makes any warranty, express or implied and assumes no legal liability or responsibility for the accuracy or completeness of any apparatus, product, process or data described previously. This report was prepared by ITRC as an account of work done to date.
Irrigation Training & Research Center August 2013
IRRIGATION
TRAINING &
RESEARCH
CENTER
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
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ACKNOWLEDGEMENTS
ITRC would like to acknowledge the following valve manufacturers for cooperation during the testing:
Eurodrip USA Jain Irrigation John Deere Water Technologies Nelson Irrigation Netafim
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EXECUTIVE SUMMARY
The Irrigation Training & Research Center (ITRC) at California Polytechnic State University (Cal Poly) San Luis Obispo tested performance characteristics of pressure regulating valves from a variety of manufacturers. The purpose of the testing was to evaluate the ability of different models of valves to regulate the pressure in a low-pressure system. The testing concentrated on three specific valve performance characteristics: Minimal variance from the target downstream pressure caused by changes in flow rate or
inlet pressure Minimal hysteresis in outlet pressures Minimal pressure loss (at low inlet pressures) across the valve The testing results indicated the following key points: Pressure regulating valves with 2-way pilots are not suited for truly low pressure systems
due to an inherently higher pressure differential. In other words, if the valves with 2-way pilots are adjusted to regulate an outlet pressure of 13 psi, the majority of valves tested required an inlet pressure of 20 psi to function.
All of the comparable valves with 3-way pilots were affected by the following performance characteristics: o Regulated outlet pressure consistency. Within a specific operating range, the majority
of valves with 3-way pilots have the ability to maintain an outlet pressure of +/- 1.5 psi. Only one valve was able to maintain an outlet pressure within +/-0.5 psi.
o Hysteresis. All of the valves with 3-way pilots exhibited measureable differences in regulated outlet pressures between ON and OFF cycles. Some valves exhibited as much as a 2 psi difference in regulated outlet pressures due to hysteresis.
Many of the valves received by ITRC had incorrect diaphragms or pilot springs installed despite extensive specification of performance requirements and were thus not suited for this research application. It is therefore critical that end users supply specific performance requirements to irrigation dealers and verify the configuration before installation.
ITRC staff followed suggestions from industry professionals to verify that the following potential issues did not adversely affect the test results: o The addition of an air vent directly upstream of the test valve. It was suggested that
the lack of an air vent upstream of the test valve may allow the accumulation of air within the pilot and the chamber above the valve diaphragm. Multiple performance tests were conducted with similar results to those without the air vent. Although ITRC typically recommends the installation of adequate continuous acting air vents along pipeline systems, it had no effect in this instance.
o Insufficient flow rate was present to allow the valve to function as designed. It was believed that some valves required a minimum pressure differential to function properly, and that testing 4 inch valves at 200 gallons per minute did not provide the valves with optimal conditions. Test 1 was conducted with 4 inch valves at flow rates up to 500 gallons per minute without substantial differences in results.
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TABLE OF CONTENTS
Executive Summary .......................................................................................................... ii
Introduction ........................................................................................................................1
Tests ................................................................................................................................1
Valve Assortment ............................................................................................................2
Test Results .........................................................................................................................3
Test 1: Performance with Changing Inlet Pressures ......................................................3
Pressure Regulating Valves with 2-Way Pilots ..................................................................... 4 Pressure Regulating Valves with Incorrect Configurations ................................................... 9 Pressure Regulating Valves with 3-Way Pilots and Correct Design ................................... 12
Test 2: Performance with Changing Inlet Flow Rates .................................................20
Test 3: Minimum Valve Pressure Loss at Various Flow Rates ...................................27
Attachment A. Valve Testing Protocol
Attachment B. Valve Testing Measurement and Uncertainty
Attachment C. 2-Way vs. 3-Way Pilots
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LIST OF FIGURES Figure 1. Example Test 1 graph ........................................................................................................... 3 Figure 2. Test 1 - 4-inch Bermad IR-120 (2-way pilot) ....................................................................... 5 Figure 3. Test 1 - 6-inch Bermad IR-120. 2-way pilot performance .................................................... 5 Figure 4. Test 1 - 3-inch John Deere V2000 (2-way pilot) .................................................................. 6 Figure 5. Test 1 - 3-inch Ooval PH3N00G001 (2-way pilot) ............................................................... 6 Figure 6. Test 1 - 4-inch Ooval PH0400G001 (2-way pilot) ................................................................ 7 Figure 7. Test 1 - 3-inch Ooval ZH3NRDTW02 Blue Spring (2-way pilot) ....................................... 7 Figure 8. Test 1 - 3-inch Ooval ZH3NRDTW02 Red Spring (2-way pilot) ........................................ 8 Figure 9. Test 1 - 4-inch Ooval ZH04RDG001 (2-way pilot) .............................................................. 8 Figure 10. Test 1 - 3-inch Dorot Series 100 with the high pressure diaphragm ................................... 9 Figure 11. Test 1 - 4-inch Dorot Series 100 with high pressure diaphragm ....................................... 10 Figure 12. Test 1 - 4-inch Dorot Series 100 angle valve with high pressure diaphragm ................... 10 Figure 13. Test 1 - 4-inch Ooval ZH04RDG001 with high pressure pilot spring .............................. 11 Figure 14. Test 1 - 3-inch Bermad DN80 (3-way pilot) ..................................................................... 13 Figure 15. Test 1 - 4-inch Bermad IR-120 (3-way pilot) ................................................................... 13 Figure 16. Test 1 - 6-inch Bermad IR-120 (3-way pilot) ................................................................... 14 Figure 17. Test 1 - 6-inch Dorot Series 96 (3-way pilot) ................................................................... 14 Figure 18. Test 1 - 4-inch Dorot Series 96 with metal pilot (3-way pilot) ......................................... 15 Figure 19. Test 1 - 4-inch Dorot Series 96 with high pressure diaphragm (3-way pilot) ................... 15 Figure 20. Test 1 - 4-inch Dorot Series 100 (3-way pilot) ................................................................. 16 Figure 21. Test 1 - 3-inch Dorot Super Gal (3-way pilot) .................................................................. 16 Figure 22. Test 1 - 4-inch Nelson Series 800 (3-way pilot) ............................................................... 17 Figure 23. Test 1 - 4-inch Ooval PH0400G001 (3-way pilot) ............................................................ 17 Figure 24. Test 1 - 4-inch Ooval ZA04RDA001L (3-way pilot) ....................................................... 18 Figure 25. Test 1 - 3-inch Ooval ZH3NRDG001 (3-way pilot) ......................................................... 18 Figure 26. Test 1 - 3-inch Rafael RAF-P (3-way pilot) ...................................................................... 19 Figure 27. Test 1 - 4-inch Rafael RAF-P (3-way pilot) ...................................................................... 19 Figure 28. Test 2 - 3-inch Bermad DN80 ........................................................................................... 20 Figure 29. Test 2 - 4-inch Bermad IR-120 ......................................................................................... 21 Figure 30. Test 2 - 4-inch Dorot Series 96 with low pressure diaphragm and metal pilot ................. 21 Figure 31. Test 2 - 4-inch Dorot Series 96 with high pressure diaphragm and high pressure pilot ... 22 Figure 32. Test 2 - 4-inch Dorot Series 100 ....................................................................................... 22 Figure 33. Test 2 - 3-inch Dorot Super Gal ........................................................................................ 23 Figure 34. Test 2 - 4-inch Nelson Series 800 ..................................................................................... 23 Figure 35. Test 2 - 4-inch Ooval PH0400G001 .................................................................................. 24 Figure 36. Test 2 - 4-inch Ooval ZA04RDA001L ............................................................................. 24 Figure 37. Test 2 - 3-inch Ooval ZH3NRDG001 ............................................................................... 25 Figure 38. Test 2 - 3-inch Rafael RAF-P ........................................................................................... 25 Figure 39. Test 2 - 4-inch Rafael RAF-P ........................................................................................... 26 Figure 40. Minimum valve pressure loss (during operation by pilot control) at 13 psi outlet
pressure at 400 GPM ......................................................................................................... 27 Figure 41. Test 3 - 3-inch Bermad DN80 minimum valve pressure loss values ................................ 29 Figure 42. Test 3 - 4-inch Bermad IR-120 minimum valve pressure loss values............................... 29 Figure 43. Test 3 - 4-inch Dorot Series 96 with metal pilot minimum valve pressure loss values .... 30 Figure 44. Test 3 - 4-inch Dorot Series 96 with plastic pilot minimum valve pressure loss values ... 30 Figure 45. Test 3 - 4-inch Dorot Series 96 with plastic pilot and LP diaphragm minimum valve
pressure loss values ........................................................................................................... 31
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Figure 46. Test 3 - 3-inch Dorot Super Gal minimum valve pressure loss values ............................. 31 Figure 47. Test 3 - 4-inch Nelson Series 800 minimum valve pressure loss values (no
manufacturer data provided) ............................................................................................. 32 Figure 48. Test 3 - 4-inch Ooval PH0400G001 minimum valve pressure loss values ....................... 32 Figure 49. Test 3 - 4-inch Ooval ZA04RDA001L minimum valve pressure loss values ................... 33 Figure 50. Test 3 - 3-inch Ooval ZHNRDG001 minimum valve pressure loss values ...................... 33 Figure 51. Test 3 - 3-inch Rafael RAF-P minimum valve pressure loss values ................................. 34 Figure 52. Test 3 - 4-inch Rafael RAF-P minimum valve pressure loss values ................................. 34
LIST OF TABLES Table 1. List of pressure regulating valve models with 2-way pilot designs used in Test 1 ................ 4 Table 2. List of pressure regulating valve models with incorrect hardware used in Test 1 ................. 9 Table 3. List of appropriate valves used in Test 1 .............................................................................. 12 Table 4. Minimum valve pressure loss (during operation by pilot control) at 13 psi outlet
pressure at 400 GPM ......................................................................................................... 28
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INTRODUCTION
Agricultural irrigation systems, especially drip and microirrigation systems, require constant pressures in order to avoid variations in application rates or pipe breaks due to sudden pressure surges (called “water hammer”). Therefore, in areas where pressure drops or surges are common, pipelines to the irrigation system often require pressure regulating valves at the heads of submains or manifolds. Pressure regulating (PR) valves have a two-fold purpose for agricultural irrigation: they must be able to maintain a pre-set maximum operating pressure in the water line downstream of themselves, and they also serve as isolation valves that can be used to turn an irrigation system or block on and off. Since all pressure regulating valves currently on the market can successfully provide on/off control, the testing conducted by ITRC focused solely on measuring the performance of the valves’ pressure regulation. An “ideal” PR valve should provide sufficient performance in the following areas:
Minimal variance from the target downstream pressure caused by changes in flow rate or inlet pressure. In other words, regardless of increases in the pressure or flow rate upstream of the valve (the valve’s “inlet pressure”), the valve must be able to maintain the maximum pressure in the downstream pipeline (the valve’s “outlet pressure”).
Minimal hysteresis in outlet pressures caused by cyclical (on/off) operation as exhibited between irrigation events. Irrigation systems undergo frequent pressure changes due to blocks or systems turning on and off, backflushing filters, plugged emitters, or other reasons. The pressure regulating valve must be able to respond quickly to changing flow rates and pressures with minimal variations in performance.
Minimal pressure loss (at low inlet pressures) across the valve to enable low pump outlet pressures. All pressure regulating valves require an inlet pressure that is larger than the target outlet pressure. The “pressure loss across the valve” is the difference between the target outlet pressure and the minimum inlet pressure required to produce a constant outlet pressure. In an ideal PR valve, the loss would be minimal, meaning that the valve would not require much excess inlet pressure in order to maintain a low outlet pressure.
Tests
ITRC created three separate tests to measure the performance characteristics of each pressure regulating valve based upon the points above. The three tests were designed to determine the following characteristics: (1) The ability of pressure regulating valves to maintain a constant outlet pressure, with
changes in upstream inlet pressures. (2) The ability of pressure regulating valves to maintain a constant outlet pressure, with
changes in flow rates. (3) The minimum upstream inlet pressure required to regulate an outlet pressure of 13 psi
at various flow rates
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Details regarding the test protocols are provided in Attachment A. Similarly, the measurement and calibration techniques as well as measurement hardware utilized during the valve testing is provided in Attachment B. Valve Assortment
The valves tested by ITRC were provided by manufacturers, distributors and irrigation dealers specifically for this project. Product representatives and dealers were given a specific description regarding the constraints of the testing and the expected abilities of the valves to perform at low inlet and outlet pressures. A variety of valve configurations and sizes were received by ITRC for testing that produced a range of results, sometimes directly related to the valve size or configuration. ITRC used all valves received in Test 1. During the test, two issues became apparent:
Pressure regulating valves are commonly controlled by either a 2-way pilot or a 3-way pilot. Due to the design characteristics of the 2-way pilot valves, none of the 2-way pilot valves were able to perform within the requirements of a true low pressure system application, but instead all required a substantial pressure loss across the valve body to enable downstream pressure regulation. Therefore, it was determined that two-way pilot valves are not suited to low-pressure system applications. For a description of the difference between 2-way and 3-way pilot valves, please see Attachment C.
Multiple valves were received by ITRC with incorrect hardware combinations such as pilot springs and diaphragms, which negatively affected the performance of the valves. ITRC was able to identify certain elements that made these valve combinations unsuitable for low-pressure system applications.
As a result of the two discoveries mentioned above, only correctly-equipped 3-way pilot valves were used for Tests 2 and 3.
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TEST RESULTS
Test 1: Performance with Changing Inlet Pressures
The intention of the first test was to start testing the valves at an inlet pressure above a low pressure system target level (13 psi), and then slowly decrease the inlet pressure until the inlet pressure reached 10 psi, forcing the valve to fully open in order to attempt to regulate the outlet pressure. Then, the flow was slowly increased until it reached the original test starting pressure. After the initial pilot adjustments, the pilot setting was not adjusted throughout the test. As seen in Figure 2, the graphs provided were intended to show two lines: The blue line represents the valve’s outlet pressure in relation to the inlet pressure as the inlet pressure decreases. The red line represents the outlet pressure as the inlet pressure increases back to the test’s starting pressure. A “good” valve performance would look something like the graph in Figure 2, where the valve is able to maintain the target pressure relatively well until the inlet pressure drops to slightly above to the target outlet pressure, and the valve can no longer regulate. Then, a well-performing valve should be able to repeat the same relationship in reverse, as the pressure increases again (i.e., with minimal hysteresis).
Figure 1. Example Test 1 graph
Inlet Pressure (psi)
Outlet Pressure (psi)
Target Pressure
Test Time as Pressure Decreases
Test Time as Pressure Increases
Test End
Test Start
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Pressure Regulating Valves with 2-Way Pilots
ITRC was supplied with PR valves that were plumbed with 2-way pilots. As shown in the following graphs, none of the 2-way pilot valves were able to perform satisfactorily during Test 1, because all of the models required inlet pressures that were significantly higher than the “low-pressure” test scenario of a 13 psi target outlet pressure. Two-way pilot PR valves are much better suited for situations where the inlet pressure is substantially higher than the target outlet pressure. However, since this set of tests was focused on low-inlet pressure applications, testing on these models was halted after the first half of Test 1, and none of the valves with 2-way pilots were included in Tests 2 and 3. Therefore, the graphs for the 2-way pilot designs only show the results of the decreasing-pressure part of Test 1. Table 1 lists the 2-way pilot models and their performance graphs are included in Figure 2 through Figure 9.
Table 1. List of pressure regulating valve models with 2-way pilot designs used in Test 1
Manufacturer
Model
Size (in.)
Pilot Type
Pilot Model
Spring Model
Spring P
Range (psi)
Diaphragm
Type
Bermad IR‐120 4 2‐way PC‐20 K 7 to 45 Standard
Bermad IR‐120 6 2‐way PC‐20 K 7 to 45 Standard
John Deere V2000 3 2‐way/3‐way hybrid T Standard 7 to 44 Standard
Ooval PH3N00G001 3 2‐way P‐21 Blue 7 to 144 Standard
Ooval PH0400G001 4 2‐way P‐21 Red 7 to 220 Standard
Ooval ZH3NRDTWO2 3 2‐way P‐21 Blue 7‐145 Standard
Ooval ZH3NRDTWO2 3 2‐way P‐21 Red 7 to 220 Standard
Ooval ZH04RDG001 4 2‐way P‐21 Red 7 to 220 Standard
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Figure 2. Test 1 - 4-inch Bermad IR-120 (2-way pilot)
Figure 3. Test 1 - 6-inch Bermad IR-120. 2-way pilot performance
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Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Inlet Pressure
Bermad4" IR‐120 PC‐20 PilotK Spring ( 7 ‐ 45 psi) Standard Diaphragm
Start Inlet: 31.2 psiStart Outlet: 12.9 psiFlow: 194 GPM
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Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Inlet Pressure
Bermad6" IR‐120PC‐20 PilotK SpringStandard Diaphragm
Start Inlet: 30.2 psiStartOutlet: 13.0 psiFlow: 505 GPM
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Figure 4. Test 1 - 3-inch John Deere V2000 (2-way pilot)
Figure 5. Test 1 - 3-inch Ooval PH3N00G001 (2-way pilot)
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Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Inlet Pressure
John DeereV2000 3"T PilotStandard Spring ( 7 ‐ 44 psi ) Standard Diaphragm
Start Inlet: 30.2 psiStart Outlet: 12.9 psiFlow: 200 GPM
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Outlet Pressure (psi)
Inlet Pressure (psi)
Deacreasing Inlet Pressure
Ooval3" PH3N00G001P‐21 PilotBlue Spring ( 7 ‐ 144 psi )Standard Diaphragm
Start Inlet: 57.03 psiStart Outlet: 13 psiFlow: 200 GPM
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Figure 6. Test 1 - 4-inch Ooval PH0400G001 (2-way pilot)
Figure 7. Test 1 - 3-inch Ooval ZH3NRDTW02 Blue Spring (2-way pilot)
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Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Inlet Pressure
Ooval4" PH0400G001P‐21 PilotRed Spring (7‐220 psi)StandardDiaphragm
Start Inlet: 33.6 psiStart Outlet: 12.5 psiFlow: 200 GPM
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Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Inlet Pressure
Ooval3" ZH3NRDTWO2P‐21 PilotBlue Spring (7‐145 psi)StandardDiaphragm
Start Inlet: 37.07 psiStart Outlet: 13.01 psiFlow: 202 GPM
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Figure 8. Test 1 - 3-inch Ooval ZH3NRDTW02 Red Spring (2-way pilot)
Figure 9. Test 1 - 4-inch Ooval ZH04RDG001 (2-way pilot)
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Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Inlet Pressure
Ooval3" ZH3NRDTWO2 P‐21 PilotRed Spring (7 ‐ 220 psi)StandardDiaphragm
Start Inlet: 32 psiStartOutlet: 13 psiFlow: 200 GPM
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OUtlet Pressure (p
si)
Inlet Pressure (psi)
Decreasing Inlet Pressure
Ooval4" ZH04RDG001P‐21 PilotRed SpringStandard Diaphragm
Start Inlet: 43.1 psiStart Outlet: 13.0 psiFlow: 191 GPM
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Pressure Regulating Valves with Incorrect Configurations
Four of the PR valves received showed erratic results during Test 1. Upon further inspection, it was apparent that all four had arrived with the incorrect hardware for the testing configurations: three contained diaphragms for high inlet pressure applications, and one had a high-pressure pilot spring. Therefore, these four valves were not used for Tests 2 and 3. Table 2 lists the low-performing valves used in Test 1, and their performance graphs are shown in Figure 10 through Figure 13.
Table 2. List of pressure regulating valve models with incorrect hardware used in Test 1
Manufacturer
Model
Size (in.)
Pilot Type
Pilot Model
Spring Model
Spring P
Range (psi)
Diaphragm
Type
Hardware
Issue
Dorot Series 100 3 3‐way 29‐100 Yellow 7 to 30 032 (HP) HP Diaphragm
Dorot Series 100 4 3‐way 29‐100 Yellow 7 to 30 032 (HP) HP Diaphragm
Dorot Series 100 4 3‐way 29‐100 Yellow 7 to 44 032 (HP) HP Diaphragm
Ooval ZH04RDG001 3 3‐way P‐31 Red 8‐88 Standard HP Pilot Spring
Figure 10. Test 1 - 3-inch Dorot Series 100 with the high pressure diaphragm
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (p
si)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSeries 100 3"29‐100 PilotYellow Spring (7 ‐ 30 psi)032 (HP) Diaphragm
Start Inlet: 25 psiStart Outlet: 13 psiFlow: 200 GPM
Wrong Diaphragm
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Figure 11. Test 1 - 4-inch Dorot Series 100 with high pressure diaphragm
Figure 12. Test 1 - 4-inch Dorot Series 100 angle valve with high pressure diaphragm
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18
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Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSeries 100 4"29‐100 PilotYellow Spring (7 ‐ 30 psi)032 (HP) Diaphragm
Start Inlet: 27.3 psiStart Outlet: 13.2 psiFlow: 195 GPM
Wrong Diaphragm
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (p
si)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSeries 100 Angle 4"29‐100 PilotYellow Spring (7 ‐ 30 psi)032 (HP) Diaphragm
Start Inlet: 25.02 psiStart Outlet: 13.02 psiFlow: 200 GPM
Wrong Diaphragm
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Figure 13. Test 1 - 4-inch Ooval ZH04RDG001 with high pressure pilot spring
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17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
OovalZH04RDG001 4"P‐31 PilotRed Spring (8‐88 psi)Standard Diaphragm
Start Inlet: 26.3 psiStart Outlet: 12.9 psiFlow: 197 GPM
Wrong Pilot Spring
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Pressure Regulating Valves with 3-Way Pilots and Correct Design
Fourteen of the pressure regulating valves provided to ITRC for testing contained 3-way pilots and the appropriate design for the low inlet pressure test scenarios (see Table 3). Two of the valves performed poorly despite having the correct hardware, and were not carried forward to Test 2 and Test 3. Performance graphs for these valves are included in Figure 14 through Figure 27.
Table 3. List of appropriate valves used in Test 1
*Two valves tested did not perform well during Test 1; therefore, these valves were not tested further
Valve ID
Manufacturer
Distributor
Model
Size
Pilot Type
Pilot Model
Spring Model
Spring P Range
(psi)
Diaphragm
Type
5‐A Bermad Bermad IR‐120 6 3‐way PC‐X K 7 to 45 Standard
4‐A Bermad Bermad IR‐120 4 3‐way PC‐X‐A‐P K 7 to 45 Standard
4‐B Dorot Netafim Series 96 4 3‐way 29‐100 Yellow 7 to 30 095 (HP)
4‐C* Dorot Netafim Series 96 4 3‐way 31‐310 Yellow 7 to 30 095 (HP)
4‐D Dorot Netafim Series 96 4 3‐way 31‐310 Yellow 7 to 30 179 (LP)
4‐E Dorot Netafim 100 4 3‐way 29‐100 Yellow 7 to 30 005 (LP)
4‐F Nelson Nelson 800 4 3‐way Standard Standard 5 to 50 Standard
4‐G Ooval Eurodrip PH0400G001 4 3‐way P‐31 Blue 5 to 36 Standard
4‐H Ooval Eurodrip ZA04RDA001L 4 3‐way P‐31 Blue 5 to 36 Standard
4‐I Rafael Jain RAF‐P 4 3‐way PC Blue 7 to 22 Standard
3‐A Bermad Bermad DN80 3 3‐way PC‐X‐A‐P K 7 to 45 Standard
3‐B Dorot Netafim Super Gal 3 3‐way 29‐100 Yellow 7 to 30 Standard
3‐C Ooval EuroDrip ZH3NRDG001 3 3‐way P‐31 Blue 5 to 36 Standard
3‐D Rafael Jain RAF‐P 3 3‐way PC Blue 7 to 22 Standard
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Figure 14. Test 1 - 3-inch Bermad DN80 (3-way pilot)
Figure 15. Test 1 - 4-inch Bermad IR-120 (3-way pilot)
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18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
BermadDN80 3"PC‐X pilotK Spring (7‐45 psi)Standard Diaphragm
Start Inlet: 25.01 psiStart Outlet: 13.01 psiFlow: 200 GPM
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (p
si)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
BermadIR‐120 4"PC‐X PilotK Spring (7‐45 psi)Standard Diaphragm
Start Inlet: 30.9 psiStart Outlet: 12.8 psiFlow: 199 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 14
Figure 16. Test 1 - 6-inch Bermad IR-120 (3-way pilot)
Figure 17. Test 1 - 6-inch Dorot Series 96 (3-way pilot)
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
BermadIR‐120 6"PC‐X PilotK Spring (7‐45 psi)Standard Diaphragm
Start Inlet: 29.4 psiStart Outlet: 13.6 psiFlow: 520 GPM
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSeries 96 4"31‐310 PilotYellow Spring (7‐30 psi)095 (HP) Diaphragm
Start Input: 25.01 psiStart Output: 13.02 psiFlow: 202 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 15
Figure 18. Test 1 - 4-inch Dorot Series 96 with metal pilot (3-way pilot)
Figure 19. Test 1 - 4-inch Dorot Series 96 with high pressure diaphragm (3-way pilot)
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSeries 96 4"31‐310 PilotYellow Spring (7‐30 psi)179 (LP) Diaphragm
Start Inlet: 25.05 psiStart Outlet: 12.95 psiFlow: 198 GPM
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (p
si)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSeries 96 4"29‐100 PilotYellow Spring (7 ‐ 30 psi)095 (HP) Diaphragm
Start Inlet: 24.43 psiStart Outlet: 13.3 psiFlow: 218 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 16
Figure 20. Test 1 - 4-inch Dorot Series 100 (3-way pilot)
Figure 21. Test 1 - 3-inch Dorot Super Gal (3-way pilot)
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSeries 100 4"29‐100 PilotYellow Spring (7 to 30 psi)005 (LP) Diaphragm
Start Inlet: 25.08 psiStart Outlet: 12.97 psiFlow: 197 GPM
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (p
si)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
DorotSuper Gal 3"29‐100 PilotYellow SpringStandard Diaphragm
Start Inlet: 25 psiStartOutlet: 13 psiFlow: 200 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 17
Figure 22. Test 1 - 4-inch Nelson Series 800 (3-way pilot)
Figure 23. Test 1 - 4-inch Ooval PH0400G001 (3-way pilot)
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (p
si)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
NelsonSeries 800 4"Standard PilotC1 Spring ( 10 ‐ 50 psi )Standard Diaphragm
Start Input: 30.0 psiStart Output: 13.0 psiFlow: 512 GPM
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
OovalPH0400G001 4"P‐31 PilotBlue Spring (5‐36 psi)Standard Diaphragm
Start Inlet: 25.6 psiStart Outlet: 13.2 psiFlow: 204 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 18
Figure 24. Test 1 - 4-inch Ooval ZA04RDA001L (3-way pilot)
Figure 25. Test 1 - 3-inch Ooval ZH3NRDG001 (3-way pilot)
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
OovalZA04RDA001L 4"P‐31 PilotBlue springStandard Diaphragm
Start Inlet: 25 psiStart Outlet: 13.03 psiFlow: 200 GPM
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
OovalZH3NRDG001 3"P‐31 PilotBlue SpringStandard Diaphragm
Start Inlet: 25 psiStart Outlet: 13.05 psiFlow: 200 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 19
Figure 26. Test 1 - 3-inch Rafael RAF-P (3-way pilot)
Figure 27. Test 1 - 4-inch Rafael RAF-P (3-way pilot)
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
Rafael3" RAF‐PPC pilotBlue Spring (7‐22 psi)Standard Diaphragm
Start Inlet: 25.09 psiStart Outlet: 13.08 psiFlow: 213 GPM
10
11
12
13
14
15
16
17
18
10 12 14 16 18 20 22 24 26 28 30
Outlet Pressure (psi)
Inlet Pressure (psi)
Decreasing Pressure
Increasing Pressure
Rafael4" RAF‐PPC PilotBlue Spring (7‐22 psi)Standard Diaphragm
Start Inlet: 25 psiStart Outlet: 13.33 psiFlow: 210 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 20
Test 2: Performance with Changing Inlet Flow Rates
The intention of the second test was to configure the valve inlet and discharge pressures at conditions replicating a low pressure system at a low flow rate of 100 GPM. The test proceeded by substantially increasing the flow rate to 500 GPM while maintaining the initial inlet pressure and monitoring the subsequent outlet pressure. Due to large pressure losses with some valves, a flow rate of 500 GPM was not reached. After the initial pilot adjustment, the pilot setting was not changed throughout the test. As seen in Figure 28, the graphs provided were intended to show two lines: The blue line represents the valve’s outlet pressure in relation to the flow rate through the valve. The red line represents the inlet pressure in relation to the flow rate, which remained constant throughout the test. An “ideal” valve performance would look something like the graph in Figure 34, where the valve is able to maintain the target pressure relatively well throughout a large range of flow rates.
Figure 28. Test 2 - 3-inch Bermad DN80
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (psi)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
BermadDN80 3"PC‐X pilotK Spring (7‐45 psi)Standard Diaphragm
Start Inlet: 20 psiStart Outlet: 13 psiFlow: 100 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 21
Figure 29. Test 2 - 4-inch Bermad IR-120
Figure 30. Test 2 - 4-inch Dorot Series 96 with low pressure diaphragm and metal pilot
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (psi)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
BermadIR‐120 4"
PC‐X PilotK Spring (7‐45 psi)Standard Diaphragm
Start Inlet: 20.4 psiStart Outlet: 13 psiFlow: 104 GPM
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (psi)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
DorotSeries 96 4"31‐310 PilotYellow Spring (7‐30 psi)179 (LP) Diaphragm
Start Inlet: 20.0 psiStart Outlet: 13.0 psiFlow: 100 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 22
Figure 31. Test 2 - 4-inch Dorot Series 96 with high pressure diaphragm and high pressure
pilot
Figure 32. Test 2 - 4-inch Dorot Series 100
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (psi)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
DorotSeries 96 4"29‐100 PilotYellow Spring (7 ‐ 30 psi)095 (HP) Diaphragm
Start Inlet: 20.0 psiStart Outlet: 13.0 psi
Flow: 100 GPM
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (psi)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
DorotSeries 100 4"29‐100 PilotYellow Spring (7 to 30 psi)005 (LP) Diaphragm
Start Inlet: 20.0 psiStart Outlet: 13.0 psiFlow: 100 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 23
Figure 33. Test 2 - 3-inch Dorot Super Gal
Figure 34. Test 2 - 4-inch Nelson Series 800
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (psi)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
DorotSuper Gal 3"29‐100 PilotYellow Spring ( 7 to 30 psi )Standard Diaphragm
Start Inlet: 20.0 psiStart Outlet: 13.0 psiFlow: 105 GPM
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (p
si)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
NelsonSeries 800 4"
Standard PilotC1 Spring ( 10 ‐ 50 psi )Standard Diaphragm
Start Input: 20.0 psiStart Output: 13.1 psi
Flow: 106 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 24
Figure 35. Test 2 - 4-inch Ooval PH0400G001
Figure 36. Test 2 - 4-inch Ooval ZA04RDA001L
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (p
si)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
OovalPH0400G001 4"P‐31 PilotBlue Spring (5‐36 psi)
Standard Diaphragm
Start Inlet: 20.7 psiStart Outlet: 13.0 psiFlow: 100 GPM
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (p
si)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
OovalZA04RDA001L 4"
P‐31 PilotBlue Spring (5‐36 psi)Standard Diaphragm
Start Inlet: 20.0 psi
Start Outlet: 13.0 psiFlow: 100 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 25
Figure 37. Test 2 - 3-inch Ooval ZH3NRDG001
Figure 38. Test 2 - 3-inch Rafael RAF-P
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (p
si)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
OovalZH3NRDG001 3"
P‐31 PilotBlue Spring (5‐36 psi)Standard Diaphragm
Start Inlet: 20.0 psiStart Outlet: 13.0 psi
Flow: 102 GPM
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (p
si)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
Rafael3" RAF‐PPC pilotBlue Spring (7‐22 psi)
Standard Diaphragm
Start Inlet: 20.1 psiStart Outlet: 13.2 psiFlow: 100 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 26
Figure 39. Test 2 - 4-inch Rafael RAF-P
0
2
4
6
8
10
12
14
16
18
20
22
0 100 200 300 400 500 600
Pressure (p
si)
Flow rate (GPM)
Outlet Pressure
Inlet Pressure
Rafael4" RAF‐PPC PilotBlue Spring (7‐22 psi)
Standard Diaphragm
Start Inlet: 20.0 psiStart Outlet: 13.2 psi
Flow: 99 GPM
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 27
Test 3: Minimum Valve Pressure Loss at Various Flow Rates
Test 3 examined the minimum valve pressure loss at various flow rates. This was determined by subtracting the downstream pressure at each measured flow rate from the minimum upstream pressure that still maintained the target downstream pressure. The results of the ITRC testing were then compared with the values for minimum valve pressure loss listed for each model in the manufacturers’ published specifications, as well as the values provided by the equipment distributor (if available). The overall results are presented graphically in Figure 40 and in table format in Table 4. The test vs. manufacturer value graphs are presented for each model individually in Figure 41 through Figure 52.
Figure 40. Minimum valve pressure loss (during operation by pilot control) at 13 psi outlet
pressure at 400 GPM
0
2
4
6
8
10
12
14
16
18
3‐A 3‐B 3‐C 3‐D 4‐A 4‐B 4‐D 4‐E 4‐F 4‐G 4‐H 4‐I
Minim
um Valve
Pressure Loss (psi)
Valve ID
ITRC Results
Manufacturer Values
Distributor Values
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 28
Table 4. Minimum valve pressure loss (during operation by pilot control) at 13 psi outlet pressure at 400 GPM
Minimum Valve Pressure Loss (During Operation by Pilot Control)
to Outlet 13 PSI @ 400 GPM
Notes Valve ID
Manufacturer
Distributor
Model
Size
Pilot Type
Pilot Model
Spring Model
Spring P Range
(psi)
Diaphragm
Type
ITRC M
easured
Value (psi)
Manufacturer
Stated
Value
(psi)
Distributor
Stated
Value
(psi)
4‐A Bermad Bermad IR‐120 4 3‐way PC‐X‐A‐P K 7 to 45 Standard 3.7 2.9 2.9
4‐B Dorot Netafim Series 96 4 3‐way 29‐100 Yellow 7 to 30 095 (HP) 3.7 3 3
4‐D Dorot Netafim Series 96 4 3‐way 31‐310 Yellow 7 to 30 179 (LP) 5.4 3 3
4‐E Dorot Netafim 100 4 3‐way 29‐100 Yellow 7 to 30 005 (LP) 3.7 2.1 2.6
4‐F Nelson Nelson 800 4 3‐way Standard Standard 5 to 50 Standard 0.9 No pressure loss information available online
4‐G Ooval Eurodrip PH0400G001 4 3‐way P‐31 Blue 5 to 36 Standard 3.2 2.1 2.1
4‐H Ooval Eurodrip ZA04RDA001L 4 3‐way P‐31 Blue 5 to 36 Standard 2.3 1.4 1.4
4‐I Rafael Jain RAF‐P 4 3‐way PC Blue 7 to 22 Standard 9.5 3
No pressure loss information available online from distributor
3‐A Bermad Bermad DN80 3 3‐way PC‐X‐A‐P K 7 to 45 Standard 17.3 10.5 10.5
ITRC value was extrapolated; best estimate for manufacturer stated value
3‐B Dorot Netafim Super Gal 3 3‐way 29‐100 Yellow 7 to 30 Standard 11.3 3.8 6
Best estimate of manufacturer and distributor stated values
3‐C Ooval EuroDrip ZH3NRDG001 3 3‐way P‐31 Blue 5 to 36 Standard 6.9 4.4 4.4 Best estimate of manufacturer stated value
3‐D Rafael Jain RAF‐P 3 3‐way PC Blue 7 to 22 Standard 9.6 3
No pressure loss information available online from distributor
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 29
Figure 41. Test 3 - 3-inch Bermad DN80 minimum valve pressure loss values
Figure 42. Test 3 - 4-inch Bermad IR-120 minimum valve pressure loss values
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400
Minim
um Valve Pressure loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
Bermad3" DN80PC‐X pilotK Spring (7‐45 psi)Standard Diaphragm
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve
Pressure Loss (p
si)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
Bermad4" IR‐120PC‐X PilotK Spring (7‐45 psi)Standard Diaphragm
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 30
Figure 43. Test 3 - 4-inch Dorot Series 96 with metal pilot minimum valve pressure loss values
Figure 44. Test 3 - 4-inch Dorot Series 96 with plastic pilot minimum valve pressure loss values
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve Pressure loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
DorotSeries 96 4"31‐310 PilotYellowSpring ( 7 ‐ 30 psi )179 (LP) Diaphragm
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
DorotSeries 96 4"29‐100 PilotYellow Spring ( 7 ‐ 30 psi )095 (HP) Diaphragm
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 31
Figure 45. Test 3 - 4-inch Dorot Series 96 with plastic pilot and LP diaphragm minimum valve
pressure loss values
Figure 46. Test 3 - 3-inch Dorot Super Gal minimum valve pressure loss values
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
Dorot4" Series 100 29‐100Yellow Spring (7 to 30 psi)005 (LP) Diaphragm
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
Dorot3" Super Gal
29‐100 pilotYellow Spring (7 ‐30
psi)Standard Diaphragm
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 32
Figure 47. Test 3 - 4-inch Nelson Series 800 minimum valve pressure loss values (no
manufacturer data provided)
Figure 48. Test 3 - 4-inch Ooval PH0400G001 minimum valve pressure loss values
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
NelsonSeries 800 4"StandardPilotC1 Spring ( 10 ‐ 50 psi )Standard Diapghragm
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
Ooval4" PH0400G001P‐31 PilotBlue Spring (5 to 36) psi)Standard Diaphragm
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 33
Figure 49. Test 3 - 4-inch Ooval ZA04RDA001L minimum valve pressure loss values
Figure 50. Test 3 - 3-inch Ooval ZHNRDG001 minimum valve pressure loss values
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
Ooval4" ZA04RDA001LP‐31 PilotBlue Spring (7 to 30 psi)Standard Diaphragm
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500 600
Minim
um Valve
Pressure Loss (p
si)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Values
Ooval3" ZH3NRDG001P‐31 PilotBlue Spring (7 to 30 psi)Standard Diaphragm
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | 34
Figure 51. Test 3 - 3-inch Rafael RAF-P minimum valve pressure loss values
Figure 52. Test 3 - 4-inch Rafael RAF-P minimum valve pressure loss values
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Value
Rafael3" RAF‐PPC PilotBlue Spring (7 to 22 psi)Standard Diaphragm
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 100 200 300 400 500
Minim
um Valve Pressure Loss (psi)
Flow Rate (GPM)
ITRC Results
Manufacturer Stated Results
Rafael4" RAF‐P
PC PilotBlue Spring (7 to 22 psi)
Standard Diaphragm
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center
ATTACHMENT A Valve Testing Protocol
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | A-1
Attachment A Valve Testing Protocol
Test 1 Protocol
Figure A1. Test 1 & 2 setup
1. Configure the valves and piping as shown in Figure A1.
a. The u/s gate valve is adjusted to deliver 25 psi. b. The pressure regulating valve is to be adjusted to set the downstream pressure to
13 psi. c. The downstream gate valve is adjusted to set the flow rate to 200 GPM.
2. The u/s gate valve is re-adjusted to 25 psi. NOTE: If the valve has a high inherent friction loss, it may be necessary to increase the inlet pressure to the test valve to 30-35 psi in order to record a minimum of 4-5 data points before the valve has opened to its full extent. 3. The pressure regulating valve, d/s gate valve, and u/s gate valve are all re-adjusted so that
there is 13 psi out of the test valve, 200 GPM, and 25 psi into the test valve. 4. Change the u/s gate valve in increments of 1 psi decreasing. Measure the d/s pressure
from the test valve, and the flow rate. NOTE: The remainder of Test 1, and Tests 2 and 3 may not be completed if the valve exhibits an inability to perform at a satisfactory level with a low downstream pressure. Less than satisfactory performance includes:
the valve cannot maintain a downstream pressure of 13 psi (+/- 1.5 psi) during normal operation and/or
the valve requires an inlet pressure of more than 5 psi over the regulated downstream pressure for normal operation.
5. Once arriving at 13 psi, go back upward at 1 psi at a time, to 25 psi. Measure the d/s
pressure from the test valve, and the flow rate.
Low-Pressure Testing: Pressure Regulating Valves http://www.itrc.org/reports/pdf/valves.pdf ITRC Report No. R 13-003
Irrigation Training & Research Center P a g e | A-2
Test 2 Protocol 1. Start the test for a change in flow rate. 2. Re-adjust the u/s gate valve so that the pressure into the test valve is 20 psi. 3. Fine tune the test valve and the d/s gate valve so the test valve delivers 13 psi at
100 GPM. 4. Re-adjust the u/s gate valve, the test valve, and the d/s gate valve so there is 20 psi into
the test valve and 13 psi and 100 GPM out. 5. Record the pressure in and out of the test valve, and the flow rate. 6. Re-set the d/s gate valve to a flow of 200 GPM. Re-adjust the pressure into the test valve
to 20 psi. Re-adjust until there is the 200 GPM and 20 psi. **Do not adjust the test valve pilot***
7. Record the d/s pressure. 8. Repeat (6) with flow rates of 300, 400, and 500 GPM.
Test 3 Protocol
Figure A2. Test 3 setup
1. Configure the valves and piping as shown in Figure A2. 2. The selection switch on the pressure regulating valve (“Test Valve”) has been set to
“Open”. 3. Open the pilot valve on the test valve to full open. 4. Adjust the flow control valve so that it is about 1/3 open. 5. Open the 2nd pressure reducer valve so it’s about half open. 6. Open the first pressure reducer valve so that there is about 40 psi just d/s of it. This
does not need to be precise, and can be adjusted any time. The purpose of this valve is to perform initial pressure dissipation so that the 2nd pressure reducer valve is more precise.
7. Using the flow control valve, set the flow rate to about 60 GPM. 8. Adjust the 2nd pressure reducer valve so it is delivering 25 psi. 9. Adjust the pilot of the “test valve” and the flow control valve together so that the flow
is 60 GPM at 13 psi outlet pressure from the “test valve”. 10. Re-adjust the 2nd pressure reducing valve so it is delivering 25 psi. 11. Again, adjust the flow control valve and pilot of the “test valve” so it is delivering
about 60 GPM 12. Record:
a. The pressure d/s of the “test valve” (it should be precisely 13 psi on this first go-around)
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b. The pressure u/s of the test valve (it should be 25 psi) c. The flow rate through the valve (it should be precisely 60 GPM), as measured by
the magnetic meter. 13. Adjust the 2nd pressure reducing valve so that 24 psi enters the Test Valve. If
necessary, adjust the pilot valve so that it delivers 13 psi 14. Repeat step (12) in 1 psi increments until the pilot valve is wide open, and it can’t
deliver 13 psi d/s. NOTE: this can go fairly fast – just reduce the inlet pressure to the test valve until the downstream pressure drops and remains below 13 psi. The flow rate should also drop (~5-15 GPM). Then slowly increase the u/s pressure (likely by a half a psi or so) until it just barely delivers 13 psi and the right GPM. 15. Record the precise inlet pressure, the 13 psi, and the flow rate. 16. Then drop the pressure into the test valve by 1 psi. Adjust the flow rate to 60 GPM
with the flow control valve. Record the P d/s of the test valve. 17. Drop the pressure into the test valve by 1 more psi. Adjust the flow rate to 60 GPM
with the flow control valve. Record the P d/s of the test valve. 18. For each test valve, steps 1-15 should be repeated for the following additional flow
rates: 100, 200, 300, 400, and 500 GPM
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ATTACHMENT B Valve Testing Measurement and
Uncertainty
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Attachment B Valve Testing Measurement and Uncertainty
The valve testing focused on two types of measurements: pressure and flow rate. These physical characteristics were measured directly with the following devices: 1) Pressure
a. Inlet pressure transducer: KPSI Series 27 0-100 psi (0.25% full-scale accuracy) pictured in Figure B1.
Figure B1. Inlet pressure transducer, KPSI Series 27
b. Inlet pressure gauge: Ashcroft 0-100 psi for redundancy only, pictured in Figure B2 across from the pressure transducer
Figure B2. High quality Ashcroft pressure gauge
c. Outlet pressure transducer: KPSI Series 27 0-30 psi (0.25% full-scale accuracy) as shown in Figure B3.
Figure B3. Outlet pressure transducer, KPSI Series 27
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2) Flow rate: Seametrics AG2000 magnetic meter (+/- 1% accuracy) as pictured in Figure B4.
Figure B4. Seametrics AG2000 magnetic flow meter
The signals from these devices are measured by a high-quality, industrial SCADAPack350 programmable logic controller (PLC) featuring a 14-bit analog-to-digital converter, as shown in Figure B5.
Figure B5. SCADAPack 350 in enclosure
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The PLC converts these 4-20 mA and pulse signals to pressures and flows respectively, which are then displayed through a PC human machine interface (HMI) for the tester to observe and take data points. These data points are then manually entered into a spreadsheet for graphing and analysis purposes, while the PLC is continuously data logging all inputs at 2-second intervals. The HMI workstation is shown in Figure B6.
Figure B6. Valve testing HMI
The HMI displays averaged values for flow and pressures at 1-second and 10-second intervals. The combination of virtually instantaneous readings for adjustments between data points and the longer average for data point verification enables efficient and accurate data collection. Calibration and Uncertainty
The pressure transducers and gauges were calibrated using a Druck DPI610. Because this high-quality laboratory grade pressure controller is capable of 0.025% full-scale accuracy, it can easily verify and maintain the accuracy published by KPSI (0.25%). Uncertainty analyses were completed for all valve testing measurements and the results are summarized in Table B1.
Table B1. Valve testing measurement uncertainty
Measurement Uncertainty
Inlet Pressure +/‐ 0.13 psi
Outlet Pressure +/‐ 0.04 psi
Flow Rate +/‐ 1.05% of reading
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ATTACHMENT C 2-Way vs. 3-Way Pilots
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Attachment C 2-Way vs. 3-Way Pilots
Valve Operation Automatic hydraulic pressure regulating valves regulate their outlet pressure by increasing or decreasing the cross-sectional area of the water flow channel. This action directly affects the pressure loss across the valve body and subsequently the outlet pressure. The cross-sectional area of the water flow channel is determined by the position of the (direct or indirect) diaphragm, an elastic sheet typically constructed of rubber. The diaphragm is subjected to a differential water pressure: the pressure at the valve body inlet (plus the kinetic energy of flowing water) is applied to the bottom of the diaphragm, and a controlled water pressure is applied to the top of the diaphragm. A large spring also applies pressure downward on the diaphragm. A pilot valve directly controls the water pressure applied to the top of the diaphragm. The pilot valve houses a pilot spring, its own small diaphragm, and a spool. The position of the spool directs water to different passages and subsequently through tubes to the top of the diaphragm (bonnet). All pilot valves can increase or evacuate water pressure from the bonnet. The numerical operator in pilot descriptions (“2-way” and “3-way”) represents the number of spool positions inside of the pilot. Both types of spools have the following positions:
1) Filling the bonnet: Water from the valve body inlet is directed to the bonnet to decrease the cross-sectional area of the water flow path, thus decreasing the outlet pressure
2) Evacuating the bonnet: Water from the bonnet is evacuated, thus increasing the water flow path area and increasing the outlet pressure
3-way pilots have a third “rest” position, were all water movement into and out of the bonnet is stopped. The key difference between 2-way and 3-way pilots is that 3-way pilots evacuate bonnet pressure (water) to atmosphere. This allows the bonnet to more or less fully open, as only the spring is pushing down while the full inlet pressure is opening the water flow path. In contrast, 2-way pilots vent to the outlet side of the valve body, thus always having a lower pressure differential across the bonnet and never fully opening.
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3-Way Pilots: A 3-way pilot allows the valve to be operated with a pressure loss equivalent to an
open valve body. When fully open the pilot itself does not inherently introduce additional friction loss.
In “auto mode” the 3-way pilot controls the flow of water (i.e., pressurizing) to the top of the valve diaphragm in 3 discrete operations. These operations are based upon a three-way spool inside the base of the pilot valve with these functions:
o Closing the valve: When the d/s pressure, acting on the pilot diaphragm, can overcome the pilot spring force the spool moves and connects the u/s pressure to the bonnet
o Static: When the d/s pressure, acting on the pilot diaphragm, matches the pilot spring force the spool moves into a static mode.
o Opening the valve: When the d/s pressure, acting on the pilot diaphragm, creates a thrust force less than the pilot spring pressure, the valve vents/empties the bonnet to atmosphere. If the valve continues to open, the bonnet pressure can be decreased to atmospheric pressure which allows the valve to fully open.
Figure C1. Bermad plumbing diagram from 100 Series
Notes:
With this design, it is difficult for the valve to hold a constant pressure as the inlet pressure changes. ITRC testing determined that these valves may be able to hold within +/- 1-1.5 psi when they are turned on and off.
For a 9 psi emitter (avg P), this variation can cause a drop in field (system) DU from an expected 0.93 down to as low as 0.88.
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Figure C2 estimates the 3-way pilot control techniques as a function of bonnet pressure versus time.
Figure C2. Theoretical regulation of outlet pressure after an inlet pressure increase
With 3-way pilots, the best way to set them is to adjust the pressure. Then shut off the valve. Then turn the valve on again and check the pressure. If it isn't the target, repeat the procedure until it's correct.
2-Way Pilots: A 2-way pilot introduces considerably more friction loss in the valve. Evidently, it
keeps the valve partially closed even when it is “wide open”. In “auto mode” the 2-way pilot controls the flow of water (i.e., pressurizing) to the
top of the valve diaphragm in two discrete operations. These operations are based upon a two-way spool inside the base of the pilot valve with these functions:
o Closing the valve: When the d/s pressure, acting on the pilot diaphragm, can overcome the pilot spring force the spool moves and connects the u/s pressure to the bonnet
o Opening the valve: When the d/s pressure, acting on the pilot diaphragm, creates a thrust force less than the pilot spring force the spool moves and vents the bonnet to the d/s side of the valve.
Because the 2-way pilot must vent to a pressurized d/s port, the valve is not able to fully creating an inherent minimum loss across the valve.
With 2-way pilots, the bonnet pressure is continuously being pressurized and vented, requiring a small but consistent flow through the pilot/bonnet creating an increased potential for plugging of the u/s tubing filter.
The advantage of the Bermad 2-way pilot is that there is virtually no hysteresis. Additionally, also if the inlet pressure changes, the discharge pressure does not.
12.2
12.4
12.6
12.8
13
13.2
13.4
13.6
13.8
14
14.2
0 10 20 30 40 50 60 70 80
Regulated Outlet Pressure (psi)
Time (sec)
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Published Valve Losses
It also appears that the published valve losses are always without a pilot installed (i.e., with the valve body only). For Bermad valves, losses through valves with 3-way pilots are published without pilots (as they can fully open) regardless of the presence of a pilot. However, for valves with 2-way pilots, Bermad publishes similar valve loss tables with a “2-way circuit ADDED HEAD LOSS” for velocities under a given threshold. See Figure C3.
Figure C3. Bermad published losses