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The Use Of Spring-loaded Safety Valves Must Be Known: The Working Principle Of Spring-loaded Safety Valves
Dec 17, 2018

The use of spring-loaded safety valves must be known: the working principle of spring-loaded safety valves

The spring type safety valve refers to the valve of the valve or the sealing member of the valve is locked by the elastic pressure of the spring. Once the pressure generated by the abnormal pressure of the pressure vessel will overcome the spring pressure of the safety valve, the locking device is opened and formed. A pressure relief channel is used to vent the high pressure.

According to the different opening height of the flap, it is divided into two types: full-lift and micro-start. The full-lift type has a large amount of venting, good resilience, and is suitable for liquid and gaseous media. The micro-start type is only suitable for liquid media.

According to the analysis of the opening behavior of the spring type safety valve, it can be concluded that under the action of the external force FW, a safety valve is closed from open to open, and then from open to closed.

In this whole process, the variation law of the external additional force FW, when the additional force is gradually increased from zero, and the sum of the internal pressure PL×S is just the spring pre-tightening force, the valve is slightly opened, increasing the medium acting area S, The internal pressure acting to overcome the spring preload force is sharply increased, and as a result, the external additional force is instantaneously reduced. Thus the first characteristic peak A appears.

When the external additional force gradually decreases and reaches the closing point, since the area of the medium is suddenly reduced, in order to maintain the balance of the force, at this time, the external additional force will appear to rise instantaneously, that is, the second characteristic peak point B. The above two characteristic peak points A and B are the technical basis for detecting the opening pressure and the return pressure of the safety valve under the on-line condition.