PRESSURE RELIEF / PRESSURE SUSTAINING VALVE

A.	Supply a insert size Singer Model specify model as 106/S106/206/S206 –RPS Pressure Relief / Pressure Sustaining Control Valve.

The valve shall be equipped with the following available options:

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Singer Valve schematic specify.

Function: The valve shall be a pilot operated pressure relief/pressure sustaining control valve which will open quickly when the inlet pressure meets or exceeds a predetermined pilot pressure setting to relieve damaging overpressure and closes smoothly at an adjustable speed. On pressure sustaining service the valve will maintain a relatively constant upstream pressure.

Operation: The pilot shall be a normally closed Singer Model 81-RP Pressure Relief/Sustaining Pilot that remains closed when the upstream pressure is below the pilot setting. When inlet supply pressure exceeds the pilot setting the 81-RP pilot opens to relieve the bonnet pressure which opens the main valve. When inlet pressure drops below the setting of the pilot, the pilot closes and the main valve closes. In pressure sustaining the pilot reacts to small changes in the inlet supply pressure which acts to modulate the main valve bonnet pressure, hydraulically adjusting the inner valve assembly position to maintain a constant upstream pressure.

Quality Assurance

The control valve shall be tested prior to shipment. The standard test shall include a functional stroke test and pressure and leak test of valve body, seat, fitted pilots and accessories.

The control valve shall be covered by a minimum three (3) year warranty against defects in materials and workmanship. The 316 stainless steel seat ring shall be covered by a lifetime guarantee.

All control valve maintenance and repairs shall be possible without removing the main valve body from the line, when installed in accordance with manufacturer’s recommendations.

Main Valve

The main valve shall be a Singer insert main valve model number (106/S106/206/S206) -PG single chamber, diaphragm actuated specify (full/reduced) port model.

Main valves of 6” (150mm) and larger shall provide smooth frictionless motion to ensure a low flow stability to specify minimum USGPM or L/s, achieved using SRD-Single Rolling Diaphragm technology.

The main valve, bonnet and removable stem cap shall be constructed of ASTM A536 (Grade 65/45/12) ductile iron.

Main valves of 3” (80mm) and larger shall have a removable stem cap for access to the main valve stem for alignment check, spring installation and ease of service and assembly.

The main valve trim, consisting of seat ring and stem shall be constructed of AISI 316 stainless steel.

The main valve shall provide a drip-tight seal using a mechanically retained resilient disc against the stationary AISI 316 stainless steel seat ring.

All internal and external ferrous components, including all mating surfaces, shall be coated with an NSF-61 approved fusion bonded epoxy to a minimum of 8mils DFT-Dry Film Thickness.

The main valve elastomers: diaphragm, resilient disc and seals, shall be of EPDM or Buna-N.

All main valve fasteners (bolts, nuts, studs, cap screws) shall be supplied as AISI 18-8 or 304 stainless steel. All bonnet bolts shall be fitted with stainless steel washers to prevent damage to the bonnet coating.

Valve shall have flanged, threaded or grooved end connections. Flanged connections shall be specify ANSI/ASME B16.42 Class 150#/300# OR ISO PN10/16/25/40 flange drilled, faced and rated. Threaded connections shall be specify NPT/BSPT.

Pilot Controls

The pressure relief/sustaining pilot shall be a Singer Model 81-RP normally closed pilot with a spring to adjust the pressure setting.

The pilot trim, consisting of a seat ring, stem and inner valve, shall be constructed of AISI 316 stainless steel.

The pilot elastomer: diaphragm, inner valve and seals, shall be of EPDM or Buna-N.

The adjustable pilot spring range shall be supplied with a spring range of specify range (20 to 200psi, 5-50psi, 10-80psi or 100-300psi). The pilot shall be factory preset at specify setpoint psi.

The pilot body and spring casing shall be constructed of specify material (ASTM B62 bronze or ASTM A351 CF8M stainless steel.

A fixed restriction shall be supplied as AISI 303 stainless steel with an orifice bore selected by the manufacturer based on the valve size and operation.

An adjustable needle valve closing speed control shall be supplied as specify material ASTM B16 brass or AISI 316 stainless steel.

The pilot fittings shall be supplied as specify material ASTM B16 brass or AISI 316 stainless steel.

The pilot tubing shall be supplied as specify material ASTM B280 seamless copper or AISI 316 stainless steel or PTFE lined flexible braided stainless steel.

For valves 3” (80mm) and larger, (3) pilot isolation ball valve(s) shall be supplied. Pilot isolation ball valves shall be constructed of specify material B16 Brass or 316 Stainless Steel with handle operator.

For valves 3” (80mm) and larger, a pilot strainer shall be supplied as standard. Strainer material to be ASTM A351 CF8M stainless steel with a 40-mesh or 80-mesh 316 stainless steel screen. The external pilot strainer shall have a removable plug for easy maintenance access to the pilot screen and have provision for installation of a ball valve for pilot screen flushing.

Control Valve Components – Available Options

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