Industrial applications of spring safety valves:
With the rapid development of industrialization, the company’s own business philosophy has also undergone significant changes. In the past, people always said that companies are pursuing economic benefits, but now, with the mandatory implementation of the national safety production policy, they are also seeking Under the premise of maximizing benefits, the concept of “safe production” has begun to penetrate into the hearts of business owners. Therefore, new types of safety equipment that continue to appear have been promoted and used in the workshops and production chains of various types of chemical plants. Among them, the spring type The safety valve is favored by factories for its high safety and stability. So what is the reason for it to attract attention?
The spring-loaded safety valve refers to the sealing parts such as the valve flap or plunger relying on the elastic pressure of the spring. Once the pressure of the pressure vessel is abnormal, the high pressure generated will overcome the spring pressure of the safety valve, so the locking device is opened and formed A pressure relief channel is used to release the high pressure to avoid harmful accidents. As we all know, many chemical companies need high temperature and high pressure for chemical reactions in production. If these media are not well controlled, then once a safety accident occurs , The harm caused is not only the production loss of the enterprise, but also the life safety of the operators. In order to ensure foolproof, the state stipulates that high-pressure production enterprises must install spring-type safety valves to eliminate production hazards.
Of course, the powerful safety performance of high-pressure safety valves is inseparable from their sophisticated production processes. Generally speaking, safety valve manufacturers will make them according to the applicable medium when selecting materials. Cast iron, aluminum alloy, cast steel and stainless steel materials are The best material for the safety valve. In addition, the housing of the safety valve must not have cracks and small holes during the processing process. Do not underestimate this point. The fatal danger is caused by small negligence. Finally, the most important thing is to For testing work, the safety valve that has just been produced must pass a complete set of tests before it can enter the market. The test is to be responsible for consumers and for industrial safety production.
After several generations of development, the application range of safety valves has become wider and wider, and more safety equipment that meets the needs has entered the market. And more and more companies have established their own brands, precisely because the future industrial production must also take into account safety With benefits, the prospect of safety equipment is broad and the market is broad!
Application and failure analysis of spring safety valve
The spring safety valve is a device set up for the exhaust pipe being blocked due to misoperation or uncleaned. The spring safety valve is a device that limits the pressure cooker to exhaust within the safe pressure range and ensures safe use. The structure and performance of the spring are the valve’s The essential.
According to the ratio of the maximum opening height of the valve flap to the diameter of the safety valve flow path, the spring safety valve can be divided into two types: spring micro-open closed high-pressure safety valve and spring full-open safety valve.
A. Spring micro-open closed high pressure safety valve
The opening height of the micro-lift safety valve is less than 1/4 of the diameter of the flow channel, usually 1/40 to 1/20 of the diameter of the flow channel. The action process of the micro-lift safety valve is proportional action and is mainly used in liquid applications. , Sometimes also used in gas occasions with small emissions.
B. Spring full lift safety valve
The opening height of the full-lift safety valve is greater than or equal to 1/4 of the diameter of the flow channel. The discharge area of the full-lift safety valve is the smallest cross-sectional area of the valve seat throat. Its action process is a two-stage action type, which must be aided by one The lift mechanism can be fully opened, and the full lift safety valve is mainly used for gas medium occasions.
C. Open type safety valve
The opening height is between the micro-open type and the full-open type. It can be made into a two-stage action or a proportional action type.
Common failures and elimination methods of spring-type safety valves
(1) The disc does not return to its seat after discharge. This is mainly caused by the spring bending the valve stem, the incorrect installation position of the disc or the jam. It should be reassembled.
(2) Leakage. Under the normal working pressure of the equipment, the leakage between the valve disc and the valve seat sealing surface exceeds the allowable degree. The reasons are: there is dirt between the valve disc and the valve seat sealing surface. A lifting wrench can be used Open the valve several times to flush away the dirt; the sealing surface is damaged. According to the degree of damage, it should be repaired by grinding or grinding after turning; the valve stem is bent, tilted or the lever and fulcrum are deflected, so that the valve core and the valve disc Dislocation. Should be reassembled or replaced; spring elasticity is reduced or loses elasticity. Measures should be taken to replace the spring and readjust the opening pressure.
(3) It does not open when the specified pressure is reached. The cause of this situation is that the constant pressure is inaccurate. The compression of the spring or the position of the weight should be readjusted; the disc and the valve seat are stuck. The safety valve should be manually operated on a regular basis Vent or water discharge test; the lever of the lever-type safety valve is stuck or the heavy hammer is moved. The position of the heavy hammer should be readjusted and the lever can move freely.
(4) The pressure continues to rise after exhaust. This is mainly because the selected safety valve has a small displacement and the safety discharge volume of the equipment, and a suitable safety valve should be selected again; the center line of the valve stem is not correct or the spring is rusted, so that the valve disc cannot be opened. The valve stem should be reassembled or the spring should be replaced if the height should be; if the exhaust pipe is not enough, an exhaust pipe that meets the safe discharge area should be adopted.
(5) The valve flap frequently jumps or vibrates. The main reason is that the spring stiffness is too large. Springs with appropriate stiffness should be used; the adjustment ring is improperly adjusted, so that the return pressure is too high. The position of the adjustment ring should be readjusted; the discharge pipe resistance is too large , Resulting in excessive discharge back pressure. The resistance of the discharge pipeline should be reduced.
(6) The opening is less than the specified pressure. The main reason is that the constant pressure is inaccurate; the spring is aging and the elastic force is reduced. The adjustment screw should be properly tightened or the spring should be replaced.