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 relief valve, so that the pressure in the pipeline will not exceed a certain limit value. The needle pressure relief valve adjusts the pressing force by adjusting the length of the spring force in the valve. When the pressure in the pipeline is higher than the set value, the spring is pressed reversely, so that the sealing thimble opens and the oil leaks out, which plays the role of protecting the equipment and adjusting the system pressure.
Safety Valve:
Broadly speaking, the so-called safety valve includes pressure relief valve. From the perspective 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, and others are generally called relief valve.
Difference between safety valve and relief valve:
Safety valve and pressure relief valve are very similar in structure and performance. Both of them automatically discharge the internal medium when the opening pressure is exceeded, so as to ensure the safety of the production device. When people use the two, they will be similar in essence. In addition, some production devices also specify which one can be selected in the rules. Therefore, the differences between the two are often ignored. Thus, there are many problems.
According to the definition set forth in section I of ASME Boiler and Pressure Vessel Code:
(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 full opening action of sudden opening. For gas or steam applications.
(2) Relief valve, also known as overflow 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 occasions.
