When the valve leaks under the normal working pressure of the equipment, the leakage of medium in the disc and seat sealing surface of the 2 Tph gas fired industrial steam boiler safety valve occurs in excess of the permitted degree, and the continuous leakage of the medium will also destroy the hard sealing material. Therefore, when the working medium is a steam safety valve, the sealing performance is considered to be qualified if it is invisible to the naked eye at the outlet end and can not be detected under the specified pressure value.
2, the leakage phenomenon at the joint surface between the upper and lower valve bodies of the valve body joint face leakage, the main causes of this leakage are as follows: a, the bolt tightening force of the joint face is insufficient or the tight deviation, resulting in bad sealing surface of the joint surface. B, the sealing surface of the joint face is not good. B, the sealing surface of the joint surface is not good. The tooth-shaped gasket of the valve body joint surface does not conform to the standard. C, the flatness of the valve body joint surface of the 2 Tph gas fired industrial steam boiler safety valve is too poor or the sealing failure is caused by the hard impurity gasket.
3, the phenomenon that the main safety valve does not operate when the impulse safety valve is actuated is usually referred to as the rejection of the main safety valve. The failure of the main safety valve seriously affects the safe operation of the equipment and may cause serious accidents.
4. The main causes of this failure are as follows: on the one hand, the leakage of steam from the piston chamber of the main safety valve becomes larger or smaller, although the impulse safety valve has returned to the seat. However, there is still a high pressure of steam in the pipeline and piston chamber, and the force to push the piston downward is still great, so the return of the main safety valve is slow. The method to eliminate this fault is mainly solved by the opening of the open throttle valve and the increase of the throttle aperture. Both the opening of the throttle valve and the increase of the throttle aperture cause the steam left in the pulse tube to be discharged rapidly. Thus, the pressure in the piston is reduced, and the pressure in the piston is reduced. The thrust acting on the piston decreases rapidly, and the valve core returns to the seat rapidly under the action of the upward thrust of the steam medium in the header and the upward tension of the spring of the main safety valve itself. On the other hand, too much friction between the moving parts of the main safety valve and the fixed parts will also cause the main safety valve to return slowly. The solution to this problem is to control the clearance between the moving parts of the main safety valve and the fixed parts within the standard range.
5. The low return pressure of the safety valve has great harm to the operation of the 2 Tph gas fired industrial steam boiler. Too low return pressure will result in a large number of media overtime discharge, resulting in unnecessary energy loss.
6. The flutter relief valve of the safety valve is called the flutter of the safety valve, which is called the flutter of the safety valve during the discharge process. The occurrence of the flutter phenomenon is very easy to cause the fatigue of the metal, decrease the mechanical properties of the safety valve, and cause serious equipment hidden trouble. The main causes of vibration are as follows: on the one hand, the improper use of valves, the selection of valve discharge capacity is too large (relative to the required discharge), The elimination method should be to make the rated displacement of the selected valve as close as possible to the required discharge of the equipment. On the other hand, because the diameter of the imported pipe is too small, smaller than the inlet diameter of the valve, or the resistance of the imported pipe is too large, the elimination of the side When the valve is installed, the inlet pipe diameter of the valve is not small or the resistance of the inlet pipe is reduced. It is also a factor that causes valve flutter because the resistance of discharge pipe is too large, which can be solved by reducing the resistance of discharge pipe.
7, the frequency of relief valve refers to the safety valve back to the seat, after a slight increase in pressure, the safety valve will be opened, repeated several times, this phenomenon is called safety valve; frequency jump. The mechanical characteristics of the safety valve require that when the safety valve reaches the prescribed opening height during the operation of the safety valve, the phenomenon of blockage, tremor and frequency jump is not allowed. Frequency jump phenomenon is very unfavorable to the sealing of safety valve, and it is easy to cause leakage of sealing surface. The reason is mainly related to the safety valve return pressure is too high, when the return pressure is high, the excess medium discharge in the container is less, the safety valve has already returned to the seat, when the operator adjust improperly, the pressure in the container will be again. It rises very quickly, so it causes safety valve action, which can be eliminated by opening the throttle valve. After the throttle valve is opened, the steam source leading to the piston chamber of the main safety valve is reduced, the force to push the piston down and the operation probability of the main safety valve are less, thus avoiding the continuous start of the main safety valve.
