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 Pressure Relief Valves are guaranteed to provide effective and reliable pressure relief.
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 numerous valve types, from flanged to spring-loaded, threaded to wireless, pilot operated, and much more.
View are full range of Pressure Relief Safety Valves below:
Air Pressure Relief Valves: Purpose & functionality.
A pressure relief valve is a type of safety valve designed to control the pressure in a vessel. It protects the system and keeps the people operating the device safely in an overpressure event or equipment failure.
How does a pressure relief valve work?
A pressure relief valve is designed to withstand a maximum allowable working pressure (MAWP). Once an overpressure event occurs in the system, the pressure relief valve detects pressure beyond its design's specified capability. The pressure relief valve would then discharge the pressurized fluid or gas to flow from an auxiliary passage out of the system.
Below is an example of one of our pilot operated pressure relief valves in action; the cutaway demonstrates when high pressure is released from the system.
Farris 3880 Pilot Operated Pressure Relief Valve:
Pressure Relief Valve Applications
Air pressure relief valves can be applied to a variety of environments and equipment. Pressure relief valves are a safety valve used to keep equipment and the operators safe too. They're instrumental in applications where proper pressure levels are vital for correct and safe operation. Such as oil and gas, power generation like central heating systems, and multi-phase applications in refining and chemical processing.
Types of PRVs
At Curtiss-Wright, we provide a range of different pressure relief valves based on two primary operations – spring loaded and pilot operated. Spring-loaded valves can either be conventional spring-loaded or balanced spring-loaded.
Spring-loaded valves are programmed to open and close via a spring mechanism. They open when the pressure reaches an unacceptable level to release the material inside the vessel. It closes automatically when the pressure is released, and it returns to an average operating level. Spring-loaded safety valves rely on the closing force applied by a spring onto the main seating area. They can also be controlled in numerous ways, such as a remote, control panel, and computer program.
- Operate at higher set pressures than pilot-operated relief valves
- Extensive range of chemical compatibility
- Operate at high temperatures
Pilot-Operated Pressure Relief Valves
Pilot-operated relief valves operate by combining the primary relieving device (main valve) with self-actuated auxiliary pressure relief valves, also known as the pilot control. This pilot control dictates the opening and closing of the main valve and responds to system pressure. System pressure is fed from the inlet into and through the pilot control and ultimately into the main valve's dome. In normal operating conditions, system pressure will prevent the main valve from opening.
The valves allow media to flow from an auxiliary passage and out of the system once an absolute pressure is reached, whether it is a maximum or minimum level.
When the pressure is below the maximum amount, the pressure differential is slightly positive on the piston's dome size, 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 piston's dome side. 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 repressurized, and the main valve closes. The main difference between spring-loaded prvs and pilot-operated is that a pilot-operated safety valve uses pressure to keep the valve closed.
Pilot-operated relief valves are controlled by hand and are typically opened often through a wheel or similar component. The user opens the valve when the gauge signifies that the system pressure is at an unsafe level; once the valve has opened and the pressure has been released, the operator can shut it by hand again.
- Modulating control PORVs minimize the 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.
- Smaller design than spring-loaded valves
- Operate at pressures very close to the setpoint
- PORVs are unaffected by back pressure
- PORVs with remote sensing options are cost-effective solutions for PRV installations experiencing inlet pressure loss
- More options for control
Additional Products: wireless monitored SmartPRV
At Curtiss-Wright we also provide solutions for pressure relief valve monitoring. Historically, pressure relief valves 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.
What does a pressure relief valve do?
Air pressure relief valves, also known as PRVs or safety release valves, are installed to prevent pressure buildup. The valve opens slowly to release pressure when the level becomes too high.
Why do I need a pressure relief valve?
If the pressure within an air compressor system gets too high, one of the components inside could explode. Essentially, pressure relief valves are designed to prevent uncontrolled depressurisation events from occurring, protecting surrounding nearby equipment and employees during overpressure events.
What causes an overpressure event?
There are many causes of overpressure, but the most common ones are typically blocked discharge in the system, gas blowby, and fire. Even proper inspection and maintenance will not eliminate the occurrence of leakages. An air pressure relief valve is the only way to ensure a safe environment for the device, its surroundings, and operators.
What’s the difference between a prv and psv?
While PRV and PSV are interchangeable, there is a difference between the two valves. A pressure release valve gradually opens according to the amount of pressure it’s experiencing. In contrast, a pressure safety valve opens suddenly when the pressure hits a certain level to avoid an overpressurization and potential accident. Safety valves can be used manually and are typically used for a permanent shutdown. Air pressure relief valves are used for operational requirements, and they gently release the pressure before it hits the maximum high-pressure point and circulates it back into the system.
How often should I test air pressure relief valves?
Pressure relief valves should be subject to an annual test, one per year. The operator is responsible for carrying out the test, which should be done using an air compressor. It’s imperative to ensure pressure relief valves maintain their effectiveness over time and are checked for signs of corrosion and loss of functionality. Air pressure relief valves should also be checked before their installation, after each fire event, and regularly as decided by the operators.