Designed for highly corrosive and ultra-pure chemicals, this pressure regulator uses compressed air to control pressure with greater accuracy as compared to standard spring-controlled models.
Pressure regulators provide protection for valuable downstream instruments and filtration systems by converting fluctuating or excessive inlet pressure to a preset maximum downstream pressure. The PRA will routinely handle inlet pressure up to 150 psi and accurately maintain a downstream pressure from 5 to 125 psi.
The design of the PRA features two opposing large area frictionless rolling diaphragms. Process pressure is applied to one of the diaphragms; air pressure is applied to the other. Because the air pressure can be maintained with more accuracy than the force provided by a spring, the PRA offers greater sensitivity and less variance from set pressure than any thermoplastic pressure regulator previously available. The PRA can be used in combination with our new Stabilizer (patent pending) which measures downstream liquid pressure and provides continuous feedback control for even greater sensitivity and performance. The Stabilizer is described in detail below.
Standard connections are female NPT threaded ports. Socket, flanged and spigot connections are also available. Standard body materials are Geon® Grade 1 Type 1 PVC, Natural Polypropylene, and Kynar® PVDF. Standard seal materials are Viton® and EPDM. Some Kynar PVDF components are used in the Natural Polypropylene models for strength. External fasteners are stainless steel. For materials other than listed, please consult factory.
A relieving type air regulator is required to load the sensing port; see diagram. Series PRA pressure regulators prevent downstream pressure from exceeding the desired set pressure. Regulator will remain closed as long as set pressure is maintained. As equipment or valves downstream of the regulator begin to open and demand flow, the downstream pressure begins to fall and the regulator begins to open. As valves or equipment downstream open further, the pressure regulator continues to open until its maximum opening is reached. As the process is reversed, downstream pressure begins to increase and the regulator starts closing. When the downstream pressure again reaches set pressure the regulator closes bubble-tight.
Like any pressure regulator, the PRA prevents downstream pressure from exceeding the set point. To "maintain" a specific downstream pressure, the PRA requires an additional control, such as the patented Series PRS Stabilizer - see below.
Chart shows typical lab tested performance of 1" Regulators Flow Capacity (GPM) versus Pressure Drop-Off (PSI) Comparison of representative models with three competitors.
Drop-off is the difference between the pressure regulator set pressure and the downstream pressure. Performance curves chart, above, identifies the high flow capacities and the low pressure drop-off of regulators which result in their greater sensitivity, finer adjustability and superior accuracy as compared to competitive models.
| Pipe Size | A | B | C | D | ||||
|---|---|---|---|---|---|---|---|---|
| IN. | MM | IN. | MM | IN. | MM | IN. | MM | |
| 1/4" | 2.0 | 51.0 | 4.06 | 103.0 | 2.6 | 67.0 | 1.43 | 40.0 |
| 1/2" | 2.5 | 64.0 | 6.18 | 157.0 | 4.18 | 106.0 | 2.00 | 51.0 |
| 3/4" | 4.5 | 114.0 | 8.31 | 211.0 | 5.50 | 140.0 | 2.81 | 71.0 |
| 1" | 4.5 | 114.0 | 8.31 | 213.0 | 5.50 | 140.0 | 2.87 | 73.0 |
| 1½" | 5.0 | 127.0 | 9.56 | 244.0 | 6.81 | 157.0 | 3.37 | 86.0 |
| 2" | 7.0 | 178.0 | 12.75 | 324.0 | 7.37 | 187.0 | 5.37 | 136.0 |
| 3" | 8.0 | 203.0 | 15.06 | 378.0 | 8.62 | 220.0 | 6.43 | 168.0 |
| Valve Pipe Size | Model# w/EPDM Seals | Model# w/Viton Seals | Max. Flow Rate (GPM) | |||
|---|---|---|---|---|---|---|
| 1/4" | PRA025EP-PV | PRA025V-PV | 5 | |||
| 1/2" | PRA050EP-PV | PRA050V-PV | 10 | |||
| 3/4" | PRA075EP-PV | PRA075V-PV | 35 | |||
| 1" | PRA100EP-PV | PRA100V-PV | 50 | |||
| 1½" | PRA150EP-PV | PRA150V-PV | 70 | |||
| 2" | PRA200EP-PV | PRA200V-PV | 100 | |||
| 3" | PRA300EP-PV | PRA300V-PV | 200 | |||
| The suffix "PV" indicates Geon PVC body material. For Natural Polypropylene, change "PV" to "PF". For Kynar PVDF, change "PV" to "PF". The flow rate indicated is maximum recommended. If you have any questions, please contact factory at 973-256-3000. | ||||||
We offer a performance enhancing accessory, Series PRS (U.S. Patent Number 6,418,956) which loads the PRA with greater accuracy by reacting to actual downstream pressure. Notice on the performance graph, above, how this combination approaches theoretical perfection.
To use Series PRA to control other flow related parameters, such as flow rate, pH, viscosity, temperature, etc., a transducer, controller, and E/P or I/P converter is required.
This page continues now with information on the optional Series PRS Stabilizer. The Stabilizer is a performance enhancement, but is not required for successful use of Series PRA
The Stabilizer is a closed-loop, proportional controller. It maintains process fluid pressure at a constant, preset value by modulating air pressure to the regulator. The combination of The Stabilizer and an Air-Loaded Pressure Regulator (Series PRA, above) eliminates the need for an exotic, expensive control valve in most applications.
Standard liquid connection is ½" male NPT threaded. Standard air or hydraulic connections are 1/8" female NPT. Connection to valve air chamber should be ¼" or larger tubing. Standard body materials are Geon® Grade 1 Type 1 PVC, Natural Polypropylene, Kynar® PVDF and PTFE. Standard seal material is a PTFE diaphragm backed with Viton®. Some Kynar PVDF components are used in the Natural Polypropylene models for strength. Adjusting bolt and external fasteners are stainless steel. A Buna-N rubber seal is used in the air chamber. For connection types and materials other than listed, please consult factory.
Comparison of Air-Loaded Regulator performance with and without the Stabilizer. Note that the pressure axis in this graph shows only 16 PSI of the total range; this was done to better illustrate the effectiveness of the Stabilizer. Within this limited range, competitive regulators are below the scale and therefore are not plotted.
Performance Comparison of 1" Air-Loaded Regulator with and without The Stabilizer
Temperature, ºF (ºC) Maximum Air Pressure, PSIG (BAR)
77 (25) 125(8.6)
104 (40) 83(5.7)
140 (60) max. operating 33(2.5)
40 (5) min. operating 125(8.6)
Control Pressure Range: 5 - 100 PSIG (.3 - 6.9 BAR)
Minimum Air Pressure: Set Pressure + 15 PSI (1.0 BAR)
Maximum Control Point Pressure: 150 PSIG (10.3 BAR)
Air Pressure Ports: 1/8" NPT, female
Process Liquid Port: 1/2" NPT, male
Minimum Process Liquid Supply Pressure: Set Pressure + All Downstream Pressure Drops to Control Point + 15 PSI
The location of the Stabilizer should be chosen by the system designer, depending on the application.
1. It may be installed in a tee adjacent to the PRA to regulate pressure immediately downstream, as shown above.
2. It may be installed downstream, remote of the PRA, if precise regulation is desired at that particular location. This is called the control point. In this case, appropriate air tubing will be required from the Stabilizer back to the PRA.
Other types of remote installations may be designed as required by the application. These may require additional components or other considerations; please consult the factory for assistance.
In all cases, the air supplied to the Stabilizer should be filtered, lubricated, and regulated. The air chamber vent should be checked periodically to ensure that it is free from debris and permits continuous outflow.
MATERIAL PART#
PVC PRS-T-PV
Natural Polypropylene PRS-T-PV
Kynar® PVDF PRS-T-PF
PTFE PRS-T-TF
Above are model numbers for standard PRS configurations with PTFE diaphragm and Geon PVC air chamber. For other materials, please consult factory.
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Kynar® is a registered trademark of Arkema., FAIL-DRY® is a registered trademark
Corzan™ is a trademark of Noveon
The Stabilizer, US Patent No. 6,418,956, was designed by Plast-O-Matic Project Engineer Jerry Bloom. Used in combination with the Series PRA pressure regulator, this device is the most cost effective way to accurately maintain downstream set pressure with minimal deviation, also known as "droop." The combination of these two -- the PRA Regulator and PRS Stabilizer -- rivals or exceeds the performance of costly, exotic control valves.
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