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Safety valve common causes of failure and troubleshooting
Safety valve common causes of failure and troubleshooting: 1, the safety valve leakage 1) scale, scale, debris, etc. fall on the sealing surface can be manually exhaust (steam) purge or open clean. 2) sealing surface mechanical damage or corrosion. Available grinding or turning grinding method of repair or replacement. 3) If the spring fails due to overload or the spring is damaged due to the corrosion elasticity, the spring should be replaced. 4) Stem bending deformation or spool and valve seat bearing surface deflection, should identify the cause, reassemble or replace the stem and other components. Lever-type safety valve lever and the fulcrum deflection, the valve core and the valve seat uneven force, the lever should be corrected centerline. 2, the safety valve is not adjusted under the pressure from the seat movements 1) safety valve improper adjustment, the pressure is ignored when adjusting the actual working medium characteristics and the impact of temperature, to be readjusted. In the hot state of continuous adjustment can not be more than three times. Otherwise, the starting pressure value error is larger, can not be under the normal debugging pressure action. 2) sealing surface due to media contamination or crystallization of adhesion and rust; need to purge safety valve, serious need to study the valve core, valve seat. 3) Stem and liner between the gap is too small, expansion and stuck when heated; need to increase the gap between the stem and bushing. 4) improper adjustment or maintenance, spring-loaded safety valve spring tight tight or tight enough, lever safety valve rusty plate is too heavy or too light, the need to readjust the safety valve. 5) The valve channel is obstructed by blinds and other obstructions; timely removal of obstacles. 6) spring permanent deformation, spring should be replaced. 7) Safety valve improper selection, such as large back pressure fluctuations in the occasion, the use of non-balanced safety valve, etc., the need to replace the appropriate type of safety valve. 3, the safety valve is less than fully open state 1) The nominal pressure of the safety valve is too large, the spring stiffness is too large, the need to re-select the safety valve. 2) adjust the circle properly adjusted to be readjusted. 3) The valve disc in the guide sleeve friction is too large, to be cleaned, grinding or replacement parts. 4) safety valve exhaust pipe set improperly, gas (steam) body flow resistance, the need to re-adjust the exhaust pipe. 4, the valve flap 1) adjust the ring and the valve clearance is too large, need to re-adjust. 2) The discharge of safety valve is much larger than the required amount of discharge of the container. It should be re-selected to match. 3) Safety valve inlet pipe area is too small or too much resistance, the safety valve exhaust (steam) the amount of supply, the need to replace or adjust the safety valve inlet pipe. 4) Drainage pipe resistance is too large, the pipeline should be adjusted to reduce the resistance. 5, the valve can not be back in time 1) valve in the guide sleeve frictional resistance, the gap is too small or not coaxial, to be cleaned, grinding or replacement parts. 2) The valve opening and back seat mechanism is not adjusted, should be re-adjusted. For spring-loaded safety valves, the opening pressure can be adjusted by adjusting the spring pressure; the seat back pressure can be adjusted by adjusting the position of the lower adjusting ring. 3) Safety valve verticality exceeded, need to find vertical again. 4) Boiler pressure vessel safety valve seat sealing surface cracks. When the safety valve has never been stationed after commissioning, the rainwater may enter the safety valve body from the exhaust pipe to generate heat shock with the high-temperature medium, which may cause the valve seat sealing surface to crack. It is recommended to install a rain cover on the exhaust pipe outlet. At the same time to eliminate the crack valve seat sealing surface, if necessary, replace the safety valve. In short, the safety valve is an important part of the boiler pressure vessel. It is also a component that is prone to failure. The control of the pressure vessel safety valve on the boiler is the quality control of the safety supervision from the selection, installation, commissioning, operation, overhaul and maintenance of the safety valve. If there is an error in a certain link, it may cause an accident in the boiler pressure vessel. In recent years due to safety valve problems led to the boiler pressure vessel accidents often occur. Therefore, for the boiler pressure vessel safety valve, only from the selection, installation, commissioning, operation and maintenance of repair and strict maintenance of each process, and seriously implement the standards and procedures in order to overpressure the boiler pressure vessel state, the safety valve must be able to Take off and relieve pressure, protect the safety of its equipment. Thus ensuring the safe and economic operation of the boiler pressure vessel.