Single-seat pneumatic - valve static problem when life test

Single-seat pneumatic - valve static life test pay attention to the question 1) Single-seat pneumatic - valve life test, static pressure from seated keep seal position, as a starting point of the valve opening should reach more than 90% of the actual opening. 2) Single-seat pneumatic - valve life test, static pressure from the open position to the closed, the process of the body shall be full of the medium with pressure, medium pressure of 90%? 100% of the nominal pressure valve; Arrived at the closed position, the export side of the globe valve should be medium pressure release, cut-off valve under the condition of test medium pressure difference. Globe valves are rated differential pressure requirements, test shall be made in the rated pressure difference when test pressure difference. 3) Test operation torque, to seal test, can keep the sealing performance, under the condition of manual measuring Fu get the biggest opening and closing operation torque, moment of manual operation shall not be more than one person with globe valves are installed with driving wheel torque or products from standard operating torque. Driving mechanism of repeated deviation should be less than 5% soil test output torque. 4) Static pressure in the process of the life test, should according to the characteristics of sealing pair matching material, every opening and closing cycle of 200? 300 times, a sealing performance and operating torque. Qualified seal performance, continue to the test; Manual valve. If the operating torque change can be adjusted, operated by other matching operator cut-off valve, can not be adjusted. 5) The flow direction of the installation should be cut-off valve requirements. 6) Single-seat pneumatic - valve static pressure the record, the number of life test should pass or electric life testing machine, hydraulic, pneumatic or passed he electro-hydraulic linkage driven signal provided by the travel switch. Using electromagnetic counter records.