| 摘要 |
Process and apparatus for testing a pilot-operated safety valve, applicable to (1) a safety valve composed of a body having an inlet branch connected to a pressurized fluid container, and an outlet branch, of a valve head cooperating with a seat for controlling fluid flow between these branches, of a control actuator consisting of a piston connected to the valve head and sliding in a cylinder, forming two chambers, the operative one of which is fed with fluid, and (2) a pilot apparatus controlling the valve and comprising a pressure detection actuator whose piston is subjected to the pressure of the fluid and to the action of a spring acting against the force developed by the pressure, and a hydraulic mechanism with two cocks whose closing contact portions (311, 321) are displaced via an operating rod carrying a disc displaced by the piston, and one of which controls the fluid pressure in the control actuator and the pressure detection actuator, while the other controls the discharge of the control actuator. A constant tractive force is applied to the operating rod of the cocks to displace it against the action of the spring, the force on the rod and the displacement of the latter are measured, the force threshold corresponding to the closure of one of the cocks is determined, and the curves of displacement and force plotted against time are recorded.
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