A METHOD OF DESIGNING TRUNCATED-ROD DIFFERENTIAL SAFETY VALVES FOR THE PETROLEUM INDUSTRY

摘要

The reliability and accuracy of safety valves largely predetermine the safe operation of equipment for improving oil recovery from strata and cementing boreholes, so considerable importance attaches to reliable methods of designing such valves. Some Russian and foreign direct-acting safety valves (the medium flows in the seal) have truncated rods and rigid gates with elastic sleeves, but they have unsatisfactory accuracy and stability as well as short working life for the sleeves, which break up at pressures of not more than 20-25 MPa. In improvements to such valves, the accuracy and stability have been improved, but a deficiency of this type of design was not eliminated: the sleeve is broken by the pressure difference at the time of contact breakage with the nozzle saddle. This company has developed a differential safety valve with inverse action (medium flowing under the seal) on the basis of tests in the laboratory and the industry, which has a truncated rod and moving seal of KPSD type, whose design features and advantages have been presented in detail in [4].