An UPVC pressure relief valve is a safety device made from unplasticized polyvinyl chloride that automatically releases excess pressure from a liquid piping system. Its corrosive-resistant plastic construction makes it ideal for chemical processing, water treatment, and other industrial applications. 

How it works

UPVC pressure relief valves operate on a spring-loaded or diaphragm-based mechanism. 

• The valve remains closed under normal operating pressure.
• An adjustable spring holds a sealing diaphragm in place.
• When system pressure exceeds the predetermined set point, the force of the fluid pushes the diaphragm away from its seal.
• This opens the valve and allows the excess fluid to be discharged.
• Once the pressure returns to a safe level, the spring force closes the valve again.
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Key features

• Corrosion resistance: UPVC construction resists damage from aggressive chemicals, acids, and alkalis.
• Adjustable set pressure: The pressure at which the valve opens can be precisely adjusted and secured with a locknut.
• Durable seals: EPDM or FKM (Viton) seals ensure reliable, leak-proof performance.
• Low maintenance: The valve's simple, automatic function requires minimal servicing.
• Non-corrosive components: All parts that come into contact with the medium are corrosion-resistant for an extended service life. 
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Applications

UPVC pressure relief valves are used in a range of industries where preventing overpressure is critical for system and equipment safety. 

• Water treatment: Protects filters, pumps, and membranes from damage caused by high pressure.
• Chemical processing: Safely controls pressure in piping systems that handle corrosive liquids.
• Dosing systems: Installed on the discharge line of a metering pump, these valves prevent siphoning and reduce water hammer.
• Canal and irrigation systems: Releases excess hydrostatic pressure behind canal linings to prevent damage. 

Pressure relief vs. pressure reducing valves

While both types of valves manage system pressure, they serve different functions.