Pressure Relief Valves

Curtiss-Wright's selection of Pressure Relief Valves comes from its outstanding product brands Farris, and Target Rock. We endeavour to support the whole life cycle of a facility, and continuously provide custom products and technologies. Boasting a reputation for producing high quality, durable products, our collection of their pressure relief valves are guaranteed to give your equipment and machinery effective relief from pressure when needed. 

A pressure relief valve, an umbrella term which includes safety valves and expansion relief valves, is designed to do exactly that: relieve pressure on a system. Pressure reducing valves use spring-loaded mechanisms to control and relieve any excess pressure, and prevent any more fluid passing through until normal pressure conditions have been restored. Depending on the model, control can be provided to both dynamic and static flow conditions.

While some basic components and activations in relieving pressure may differ between the specific types of relief valves, each aims to be 100% effective in keeping your equipment running safely. Our current range includes all forms of valve, from flanged to spring loaded, threaded to wireless, pilot operated, and much more.


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Farris Target Rock

Pressure Relief Valves (PRVs): Purpose, functionality, application.

Pressure relief valves are primarily designed to protect equipment, property, the environment, and life. Allowing processing facilities to operate safely, pressure relief valves often act as the last line of defence against system overpressure which can cause catastrophic damage. 

Pressure relief valves operate by opening at a predetermined set pressure, relieving pressure by releasing process media until system pressure drops to normal operating level. At this point, the valve closes, successfully preventing damage to the equipment they are designed to protect.


Types of Pressure Relief Valves

Curtiss-Wright provide a range of different PRVs based on two main types of operation: 

Spring-loaded Pressure Relief Valves

Spring loaded safety valves rely on the closing force applied by a spring onto the main seating area.. The valve is closed as long as the force exerted by the spring is larger than the force created by system pressure.

Benefits of Spring-loaded Pressure Relief Valves

  • Can operate at higher set pressures than pilot operated relief valves
  • Large range of chemical compatibility
  • High operating temperatures

Related Products: 2600/2600L series - Process Valve, 2700 Series - Process Valve, 4200 Series - Steam Safety Valve, 6400 Series - Steam Safety Valve,1890 Series - Process Valve, 1896 Series - Steam Safety Valve, 4700 Series - Steam Safety Valve, Model 600-DA - Steam Safety Valve, Model 600-SL - Safety and Relief Valve.


Pilot-Operated Pressure Relief Valves

Pilot-operated relief valves operate by combining the major relieving device (main valve) with a self-actuated auxiliary pressure relief valve, also known as the pilot control.  This pilot control dictates the opening and closing of the main valve and responds in proportion to system pressure.   System pressure is fed from the inlet into and through the pilot control and ultimately into the dome of the main valve.  In normal operating conditions, system pressure will prevent the main valve from opening.

When the pressure is below set pressure, the pressure differential is slightly positive on the dome size of the piston, which keeps the main valve in the closed position. When system  pressure rises and reaches the set point, the pilot will cut off flow to the dome causing depressurization in the dome side of the piston. The pressure differential has reversed and the piston will rise, opening the main valve, relieving pressure.

When the process pressure decreases to a specific pressure, the pilot closes, the dome is reepressurized and the main valve closes.

Benefits of Pilot Operated Pressure Relief Valves

  • modulating control PORVs minimize release of media 
  • increasing pressure helps to maintain the pilot's seal. Once the setpoint has been reached, the valve opens. This reduces leakage and fugitive emissions. 
  • often smaller footprint than spring-loaded valves
  • can work at operating pressures very close to the set point
  • ORV’s are unaffected by backpressure 
  • PORVs with remote sensing options are cost effective solutions for PRV installations experiencing inlet pressure loss 

Related Products: 3800 Series - Process Valve, Model 600-PO - Steam Safety Valve


Additional Products: Wireless Monitored SmartPRV

At Curtiss-Wright we also provide solutions for pressure relief valve monitoring.  Historically, PRVs have been difficult or impossible to monitor. Our SmartPRV featuring a 2600 Series pressure relief valve accessorized  with a wireless position monitor alerts plant operators during an overpressure event, including the time and duration.

Find out more hereSmartPRV Information