A safety relief valve, also known as a safety relief valve, is a device that relies on the pressure of the medium to automatically relieve pressure. Depending on the application scenario, it can be used either as a safety valve or a relief valve.
In Japan, for example, there are relatively few clear definitions of safety valves and relief valves. Typically, safety devices used for large energy storage pressure vessels such as boilers are called safety valves, while those installed on piping or other facilities are called relief valves. However, according to Japan’s Ministry of International Trade and Industry (MITI) Technical Standards for Thermal Power Generation, safety valves must be specified for parts of the facility that play a key role in safety and security, such as boilers, superheaters and reheaters. And on the lower side of the pressure-reducing valve, when it is necessary to connect to the boiler and turbine, it is required to install a relief valve or safety valve. This shows that safety valves are required to be higher than relief valves in terms of reliability.
In addition, from the High Pressure Gas Management Rules of the Japanese Ministry of Labor, the Rules of the Ministry of Transportation, and the Rules of Shipowners’ Associations at all levels, there is a clear distinction between the identification and regulation of safe emissions. The valves that can guarantee the emission are called safety valves, while the valves that do not guarantee the emission are called relief valves. In our country, whether it is full opening type or micro-opening type, they are all called safety valves.
I. Overview
Safety valve is a boiler, pressure vessel and other pressurized equipment on the important safety accessories. The reliability and performance of its action is directly related to the safety of equipment and personnel, but also closely related to energy saving and environmental protection. However, some users and design departments often choose the wrong model when selecting. Therefore, this paper will analyze the selection of safety valves.
Second, the definition
In a broad sense, safety valves include relief valves. According to the rules governing the direct installation of steam boilers or a class of pressure vessels on the valve, and must be recognized by the technical supervision department, narrowly defined as a safety valve, the other is generally known as the relief valve. Safety valves and relief valves are very similar in structure and performance, they are able to exceed the opening pressure automatically discharge the internal medium to ensure the safety of the production plant. Because of this essential similarity, people often confuse the two when using them. In addition, some production units have rules that state that either one can be used. As a result, the differences between the two are often overlooked, which leads to many problems.
For a clear definition of safety valves and relief valves, refer to the ASME Boiler and Pressure Vessel Code, Title I, for elaboration:
Safety Valve: An automatic pressure relief device actuated by the static pressure of the medium in front of the valve. It is characterized by a burst-open full-open action and is mainly used for gas or steam applications.
Relief valve (also known as relief valve): also a static pressure driven by the valve medium before the automatic pressure relief device. It opens proportionally as the pressure exceeds the growth of the opening force, mainly used for fluid occasions.
