Safety valve failures are primarily due to improper design, manufacture, selection or use. If these faults are not eliminated in time, it will affect the efficacy and life of the safety valve, and even fail to provide safety protection. Personnel engaged in the operation and maintenance, disassembly inspection and inspection of safety valves in use shall obtain the "Special Equipment Operation Personnel Certificate". Common faults and elimination methods are as follows: Safety valve (1) Leakage. Under the normal working pressure of the equipment, leakage between the valve disc and the seat sealing surface exceeds the allowable degree. The reason is that there is dirt between the valve flap and the valve seat sealing direction. The valve can be opened several times with a lifting wrench. Wash the dirt away. Damage to the sealing surface should be repaired by grinding or grinding after grinding according to the degree of damage. The stem is bent, tilted or the lever is deflected from the fulcrum to displace the spool and the disc and should be reassembled or replaced. If the spring elasticity is reduced or loses its elasticity, measures such as replacing the spring and re-adjusting the opening pressure should be taken. (2) It does not open when the pressure is specified. The reasons for this are: The pressure is not allowed. The amount of compression of the spring or the position of the weight should be readjusted. The valve flap is stuck to the valve seat. The safety valve should be manually drained periodically. The lever of the lever type safety valve is stuck or the weight is moved. The weight position should be re-adjusted and the lever movement should be automatic. (3) The pressure is not opened. The main reason is that the fixed pressure is not accurate, the spring is aging, and the elastic force is reduced. It should be adapted to tighten the valve stem or replace the spring. (4) The pressure continues to rise after discharge. This is mainly because the selected safety valve displacement is less than the safety relief of the equipment, and the appropriate safety valve should be re-selected. The stem centerline is not correct or the spring is rusted, so that the valve flap cannot be opened to the proper height. The valve stem should be reassembled or the spring replaced. If the exhaust pipe section is not enough, an exhaust pipe that meets the safe discharge area should be adopted. (5) The valve flap jumps or vibrates. Mainly because the spring stiffness is too large, the spring with proper stiffness should be used instead. If the adjustment ring is not properly adjusted and the seat pressure is too high, the adjustment ring position should be re-adjusted. The discharge pipe resistance is too large, causing excessive discharge back pressure. (6) The valve flap does not return to the seat after discharge. This is mainly caused by the spring bending, the valve stem and the valve disc are not properly installed or stuck, and should be reassembled. For the safety valve to be sensitive, reliable and sealing, the maintenance and inspection must be enhanced during the operation of the boiler, pressure vessel and pressure piping. (1) Always keep the safety valve clean and prevent the valve body spring from being filled or corroded by grease and dirt, and prevent the safety valve discharge pipe from being blocked by oil or other foreign matter. Always check that the seal is intact and prevent the weight of the lever safety valve from loosening or being moved to prevent random rotation. (2) When the safety valve is found to have signs of leakage, it shall be replaced and repaired. It is forbidden to eliminate the leakage by increasing the load (such as over-tightening the adjusting screw of the spring-type safety valve or adding weight to the lever of the lever safety valve). In order to prevent the valve disc and the valve seat from being stuck by dirt such as grease in the gas, the safety can not be opened normally, and it is safe for other gases used for air, steam or with sticky dirt but not harmful to the discharge. Valves should be tested on a portable discharge periodically. (3) In order to keep the safety valve sensitive and reliable, perform regular calibration at least once a year. Regularly verified content generally includes dynamic checks and disassembly checks. The main content of the dynamic inspection is to check the opening pressure of the safety valve, the return pressure, the degree of sealing and the opening height at the rated discharge pressure, etc., which are the same as those for the safety valve. If the dynamic inspection fails, or if an abnormality such as a leak is found during operation, it shall be disassembled. After disassembly, carefully check all parts of the safety valve for cracks, scratches, abrasion, corrosion, deformation, etc., and repair or replace them according to the size and damage of the defects, and then assemble them for dynamic inspection. Bellows safety valve Special equipment users should attach great importance to the safety valve failure elimination, maintenance and inspection (maintenance) work and the lessons of related accidents and the importance of safety valves in pressure-bearing special equipment. Special equipment production and use units, especially small and medium-sized private individual enterprises should study carefully, implement the "Special Equipment Safety Supervision Regulations", strictly abide by the safe operating procedures and rules and regulations, in addition to the pressure-bearing special equipment body in use In addition to regular daily maintenance and inspection, it is also required to regularly check and maintain its safety accessories according to regulations, and incorporate into the safety management of special equipment, timely rectify hidden dangers, eliminate hidden dangers, and truly implement the main body of the enterprise. Responsibility to ensure the safe operation of special equipment. Household Gloves,Gloves Microfiber,Flock Lined Glove,Household Latex Work Glove ZHANGJIAGANG DINSHENGLIN TRADING CO.,LTD , https://www.dslhouse.com
Common fault elimination method for safety valve
Safety valve maintenance and inspection method
