What is the difference between a safety valve and a relief valve?


What is the difference between a safety valve and a relief valve?

Pressure relief valve

 

When the pressure in the pipeline is greater than the set pressure of the relief valve, the oil will flow out of the pressure relief valve, so that the pressure in the pipeline will not exceed a certain limit value. Needle type pressure relief valve is to adjust the compression force by adjusting the length of spring force in the valve. When the pressure in the pipeline is higher than the set value, the spring is pressed reversely, thus the sealing thimble is opened and the oil leakage flows out, which plays the role of protecting the equipment and regulating the system pressure.

 

Safety valve

 

Generally speaking, the so-called safety valve includes pressure relief valve. In terms of management rules, it is directly installed on steam boiler or a class of pressure vessel. The necessary condition is that the valve must be approved by the technical supervision department. In a narrow sense, it is called safety valve, while others are generally called relief valve.

 

Difference between safety valve and relief valve

Safety didlink valve and relief valve are similar in structure and performance. Both of them automatically discharge the internal medium when the opening pressure exceeds, so as to ensure the safety of production equipment. Because of the similarity in nature, people often confuse the two when they use it. In addition, some production units also stipulate in the rules which one can be selected. Therefore, the differences between them are often ignored. As a result, there are many problems.

According to the definition of ASME Boiler and pressure vessel code, part I:

(l) Safety valve is an automatic pressure relief device driven by the static pressure of the medium in front of the valve. It is characterized by a full opening action of sudden opening. For gas or steam applications.

(2) Relief valve, also known as relief valve, is an automatic pressure relief device driven by the static pressure of the medium in front of the valve. It opens proportionally as the pressure exceeds the opening force. It is mainly used in fluid applications.


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