What Is a Relief Valve?
A relief valve is a valve that automatically opens to release pressure when the pressure inside a pipe or tank increases abnormally.
Boilers, compressors, and other devices that compress gases to produce high-pressure gases are extremely hazardous.
If the pressure exceeds the design pressure of the tank and the tank ruptures, it could lead to a major accident. Relief valves are used in these areas to release pressure before a major accident occurs.
Other applications include installation at the outlet of positive displacement pumps.
Uses of Relief Valves
Relief valves are installed in tanks that hold large amounts of pressure. In particular, they are required by law to be installed in pressure vessels called Class I and Class II pressure vessels.
In such pressure vessels, if the pressure exceeds the design pressure and the tank ruptures, it could lead to a major accident.
They are also used for the outlet of positive displacement pumps.
If the outlet side of a positive displacement pump is blocked due to its structure, the pressure will increase. In such a case, a relief valve is installed to avoid pump failure.
Principle of Relief Valves
The structure of the relief valve itself is very simple, with the opening and closing of the valve controlled by a spring. The pressure can be determined by the strength of the spring.
However, with most relief valves, it is possible to adjust the pressure at which the relief valve opens by rotating the set handle like a pressure reducing valve.
However, it is important to note that relief valves will rarely open. However, it is necessary to check whether the relief valve opens at the default pressure every year, because if it does not open in case of an emergency, it will be in danger. Relief valves that have been opened once may not close properly or may open at a slightly lower pressure, so relief valves that have been operated once should be inspected as well.
Therefore, the equipment in question cannot be used when the relief valve is inspected, but do not put a manual valve or other device on the primary side of the relief valve because you do not want to do so. If you install a relief valve that you forget to open, the relief valve will lose its meaning and lead to a major accident.
In fact, in the past, major accidents have occurred due to the fact that manual valves were closed.