Conventional Valves

Conventional Safety Relief Valves (SRVs) operate based on the simple principle of force balance. These spring-loaded PSVs/SRVs consist of basic elements: an inlet nozzle mounted in the valve body (connected to the vessel or system needing protection), a movable disc to control flow through the nozzle, and a spring to manage the disc's position.

The operation of these valves relies on force balance. Under normal conditions, as long as the inlet pressure is below the set pressure or opening pressure, the disc remains seated on the nozzle, preventing flow. When the inlet pressure exceeds the set pressure, the force exerted by the pressure on the bottom of the disc overcomes the spring force. This causes the disc to lift, opening the valve and relieving the excess pressure in the system.

Once the inlet pressure drops sufficiently below the set pressure, the spring force surpasses the pressure force, causing the disc to re-seat on the nozzle, closing the valve.

An adjustable Blow Down Ring is included to manage the opening in the annular orifice, which controls the pressure build-up in the huddling chamber. This controlled pressure build-up helps to overcome the spring force, causing the disc to move away from the nozzle seat and allowing the valve to pop open. This feature enables fine adjustments in overpressure and blow down.

As a standard, unless otherwise specified, all our Safety Relief Valves are Full Nozzle Full Lift and tested for 10% overpressure.

Features

• Design: Available in Semi Nozzle or Full Nozzle Full Lift

• Metallic Seating: Ensures zero leakage

• Polymeric Sealing: Optional based on user requirements

• Bonnet Options: Choose between Open Bonnet or Closed Bonnet depending on operating temperature

• Blow Down Ring: For fine adjustment of reseating pressure

• Special Double Blow Down Design: Available upon request

• Compliance: Over Pressure and Blow Down conform to API 521 and ASME standards

• Tamper-Resistant Adjustment: Cap is either screwed or bolted to prevent tampering

• Wide Set Range: Suitable for various applications

• Accurate Low Pressure Regulation: Specially designed for large bore and semi nozzle configurations

• Material Range: Available in a wide variety of materials

• Options and Accessories:

  • Manual Lever: Available in plain or packed

  • Test Gag

  • Open Bonnet: For high temperature applications

  • Semi Nozzle: For large bore applications above 6”

  • Water Seals: For vacuum and/or seat cooling operations