Pressure Relief Valves

Pressure Relief Valves (PRV) are used to prevent over-pressurization of piping systems with positive displacement pumps. They are installed into the discharge of the pump and set to open at a higher pressure than the typical system pressure but lower than the maximum pressure of any components or piping.  

Pressure relief valves included an adjustable knob/screw, spring, and diaphragm/poppet. The diaphragm is held against the valve seat by the internal spring.  The knob/screw can be tightened (or loosened) against the spring to increase (or decrease) the setting of the relief pressure. 

Application 

Generally, pressure relief valves are recommended on most chemical feed systems. There are a few reasons: 

1. Protect the chemical feed pump from damage. Peristaltic pumps have tubes that can fail or fatigue quickly at higher pressures. Diaphragm pumps can have diaphragm failure or increased wear, or check valve seats/O-rings can become deformed and unseat. Pumps and motors may also have sensors that automatically shut down the pump and stop chemical injection or processing, causing system alarms. 
2. Protect piping, tubing, and other ancillary components on the discharge side of the pump.    
3. It can be used in conjunction with a pressure gauge and pressure switch to identify closed valves, clogged injectors, or other unusual pressure spikes. 

Installation 

Pressure Relief Valves (PRV) should be installed close to the pump. These can easily be installed on a skid within a few feet of the pump discharge.   

Pressure Relief Valves should be installed in conjunction with a pressure gauge so the valve can be properly set to the correct pressure.  A pressure switch is also recommended to notify the operator when a pressure event occurs.  

The relief side of the valve can be plumbed back into the suction piping or can be sent back to the chemical supply tank.  

Blue-White offers pressure relief valves as a standard component on all pump skids. They can also be purchased separately.    

Ordering Information 

Materials available:  PVC, CPVC, and PVDF bodies. EPDM, FKM, or Teflon diaphragms.  

Pressure ranges: 10-150 psi 

Connection types: ½” socket (True-union or Unibody) 

Part number	Description	Material  (Body/Diaphragm)	Size (in)
90008-748	Pressure Relief Valve, True Union, ½” Socket	PVC/FKM	0.50
90008-769	Pressure Relief Valve, True Union, ½” Socket	PVC/EP	0.50
90008-770	Pressure Relief Valve, True Union, ½” Socket	CPVC/FKM	0.50
90008-765	Pressure Relief Valve, True Union, ½” Socket	CPVC/EP	0.50
90018-093	Pressure Relief Valve, True Union, ½” Socket	PVC/PTFE	0.50
90008-922	Pressure Relief Valve, True Union, 1” Socket	PVC/FKM	1.0
90008-915	Pressure Relief Valve, Unibody, ½” Socket	PVC/FKM	0.50
90008-963	Pressure Relief Valve, Unibody, ½” Socket	PVC/EP	0.50
90018-032	Pressure Relief Valve, Unibody, ½” Socket	CPVC/FKM	0.50
90018-033	Pressure Relief Valve, Unibody, ½” Socket	CPVC/EP	0.50