4 replies to this topic

[zebobo]

Good evening everyone,

 

I have to protect a storage tank from overpressure only. Depending on the PSV set pressure, I can choose between weight or spring-loaded valves.

 

Assuming both valves are able to relieve the required flowrates...

 

Other than weight (leading to easier maintenance), what are the advantages of weight-loaded valves over spring-loaded valves? Can it be said that the weight loaded valves are more reliable because they are mechanically simpler?

 

Looking forward to hearing you opinions,

zebobo

[latexman]

What is the design pressure and Code of the tank?

[zebobo]

The design pressure is 0.5barg. The operating pressure is 7mbarg. 

[fallah]

 

I have to protect a storage tank from overpressure only. Depending on the PSV set pressure, I can choose between weight or spring-loaded valves.

 

Assuming both valves are able to relieve the required flowrates...

 

Other than weight (leading to easier maintenance), what are the advantages of weight-loaded valves over spring-loaded valves? Can it be said that the weight loaded valves are more reliable because they are mechanically simpler?

 

 

zebobo,

 

In fact, very low set pressure of the PSV necessitates using weight loaded PSV instead spring loaded one. But, high overpressure (almost %100) requirement of weight loaded PSV to reach full lift position will force having the set pressure almost half of the relieving pressure which would be among its disadvantages while the spring loaded PSV either needs low overpressure or even zero overpressure to reach full lift position.

[zebobo]

Operating pressure = 7mbarg

Design pressure = 0.5barg

75mbarg set P for weight loaded valve relieves required flowrate at +60% overpressure

350mbarg set P for spring loaded valve relieves required flowrate at +40% overpressure

 

In both cases, the valves relieve the required flowrate while ensuring the tank's design P is not exceeded.

 

Am I correct in saying that the weight loaded valve is more reliable because it is mechanically simpler?