This is a non-stocked item, please call +44 (0)1482 601030 or email sales@flowstar.co.uk for price and availability.
Pilot operated safety valves from several leading manufacturers. Please contact us with your requirements.
A pilot operated safety valve (POSV) is a type of pressure relief valve that uses system pressure (via a smaller auxiliary valve, called the pilot) to control the opening and closing of the main valve. It is commonly used in systems where precise pressure control and tight sealing are required at high pressures.
How it Works:
- The pilot valve senses system pressure and controls the main valve.
- When pressure is within safe limits, the pilot keeps the main valve closed by maintaining pressure on top of the valve piston or diaphragm.
- When pressure exceeds the set limit, the pilot valve opens, venting the pressure above the piston. This causes the main valve to open fully, relieving pressure.
- Once system pressure drops below the set point (with hysteresis), the pilot re-closes, restoring pressure above the piston and shutting the main valve.
Advantages:
- Tight shutoff even near set pressure.
- Higher capacity and less leakage than direct spring-loaded valves.
- Adjustable blow-down (the difference between opening and closing pressure).
- More compact for high-pressure applications.
Disadvantages:
- They are considerably more expensive than a standard safety valve.