Balanced Bellow
R019 Series Balanced Pressure Relief Valve – Bellow Type
A balanced pressure relief valve is a spring-loaded valve that incorporates a bellow or other balancing mechanism to minimize the impact of back pressure on the valve's performance. These valves are ideal for situations where built-up back pressure is too high for conventional pressure relief valves.
When superimposed back pressure is applied to the outlet of a spring-loaded pressure relief valve, it adds a pressure force to the valve disc, which combines with the spring force. This added force raises the pressure at which an unbalanced pressure relief valve will open. If the superimposed back pressure is variable, the opening pressure of the valve will also vary.
In a balanced bellow safety pressure relief valve, a bellow is attached to the disc holder with a pressure area approximately equal to the seating area of the disc. Conventional PSV/SRV valves show unsatisfactory performance when excessive back pressure develops during relief due to flow through the valve and outlet piping. The back pressure reduces the lifting force holding the valve open, causing the valve to operate unstably, manifesting as flutter or chatter.
For conventional PSV/SRV valves, built-up back pressure should not exceed 10% of the set pressure at 10% allowable overpressure. REGPORT offers Balanced Bellow Safety Relief Valves to address the issues caused by built-up or superimposed back pressure. Balanced valves can typically be installed where the total back pressure does not exceed 50% of the set pressure.
As a standard, unless specified otherwise, all our Safety Relief Valves are Full Nozzle Full Lift and tested for 10% overpressure.
Features
Design: Metallic Bellow
Seating: Metallic seating ensures zero leakage
Extension Bonnet: Available based on operating conditions
Bonnet Options: Choose between Open Bonnet or Closed Bonnet depending on the operating temperature
Blow Down Ring: Allows for fine adjustment of reseating pressure
Standards 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
Material Range: Available in a wide variety of materials