What Is The Difference Between The Heavy Hammer Lever Type, Spring Type And Pulse Type Of Safety Valve
Apr 01, 2022
Safety valves can be divided into heavy hammer lever type, spring type and pulse type according to their overall structure and loading mechanism.
1. Heavy hammer lever safety valve
The heavy hammer lever safety valve uses the heavy hammer and lever to balance the force acting on the valve disc. According to the lever principle, it can use the weight with smaller mass to obtain a larger force through the increase of the lever, and adjust the opening pressure of the safety valve by moving the position of the weight (or changing the mass of the weight).
The heavy hammer lever safety valve has the advantages of simple structure, easy and accurate adjustment, and the added load will not increase greatly due to the rise of the valve disc. It is suitable for occasions with high temperature. It was widely used in the past, especially in boilers and pressure vessels with high temperature. However, the structure of heavy hammer lever safety valve is relatively bulky, the loading mechanism is easy to vibrate, and often leaks due to vibration; The reseating pressure is low, so it is difficult to close and keep tight after opening.
2. Spring micro opening safety valve
The spring micro opening safety valve uses the force of the compression spring to balance the force acting on the valve disc. The compression of the coil spring can be adjusted by turning the adjusting nut on it. With this structure, the opening (setting) pressure of the safety valve can be corrected as needed. The spring micro opening safety valve has light and compact structure, high sensitivity, unlimited installation position, and can be used on mobile pressure vessels because of its low sensitivity to vibration. The disadvantage of this safety valve is that the added load will change with the opening of the valve, that is, with the rise of the valve disc, the compression of the spring increases and the force acting on the valve disc also increases. This is unfavorable to the rapid opening of the safety valve. In addition, the spring on the valve will reduce its elasticity due to the influence of high temperature for a long time. When used on containers with high temperature, the thermal insulation or heat dissipation of the spring is often considered, which makes the structure more complex.
3. Pulse safety valve
Pulse type safety valve is composed of main valve and auxiliary valve. It drives the action of main valve through the pulse action of auxiliary valve. Its structure is complex. It is usually only suitable for boilers and pressure vessels with large safety discharge capacity.
Among the above three forms of safety valves, the spring-loaded safety valve is widely used.
