The “POP” Action in Safety Valve?

safety valve

A spring-loaded pressure relief valve, also known as a “POP” type safety valve, is use in many industries to protect from over pressurizing of vessels, pipes, and containers. Conventional and balance bellows relief valves are the types of spring-loaded pressure relief valves. Codes and standards like IBR, ASME, API, etc require that these pressure relief valves are size to have a reliable capacity that is enough to maintain the integrity of the system by stopping the internal pressure from exceeding the design limits. The spring load pressure safety valves are design and select by the pressure relief system engineers to meet process-engineering requirements.

Safety Valve Reliability

A spring-loaded pressure relief valve can assume as a spring/mass system which is the cause of relief valve chattering. Academics have found noticeable differences in the stability of safety valves based on internal constructions. In a study, the researchers found that with 6 feet of inlet piping, valves from manufacturer X were stable in 50% of the tests while valves from manufacturer Z were stable in 100% of these tests. However, relief systems engineers tend to downplay the value of the mechanical design of pressure relief valves which are important to stability. Because of this, this article especially discusses the fundamentals of the design parameters for the inner parts of a relief valve. The intention is to employ design considerations and general operation information for use by relief system engineers. Specifically assisting with the knowledge of the effects of valve design on stability.

safety valve
safety valve

POP Movement

Spring-loaded Pressure Relief Valves are also known as “POP type safety Valves”. This valve typically pops open at its set pressure. In the beginning, the pressure differential around the valve disc produces the force to overcome the spring force and open the valve. The pop movement came out because most huddling chambers are design with an area that is almost 10% to 30% larger than the valve seat. When the pressure under the seat would be enough to lift the valve disc off the nozzle, there would be a step change in the upward forces on the spring and the valve “pops” open. The shape of the huddling chamber which is created by the shape and size of the disc holder, the position and shape of the blowdown ring, and the characteristics of the fluid being relieved together determine the initial opening force and the initial lift of the valve. To read information about all types of valves click on Aira Blog.

In the End

The “POP” type safety valves should be IBR approved for the Indian market. IBR is a short form of Indian Boiler Regulation. The IBR has set the standard design and pressure range for the safety valve to sell in Indian markets. All manufacturers who are selling their safety valves in India should make valves that fit their criteria. Aira Euro Automation pvt. ltd. is an India-based industrial valve manufacturer that follows all criteria of IBR including API, CE, ATEX, etc.

Also, read Small Overview & Types of Aira’s Safety Valve