(1) Under normal circumstances, the valve is not tested for strength, but after repair, the valve body and bonnet or the valve body and bonnet damaged by corrosion should be tested for strength. For safety valves, their constant pressure and return pressure and other experiments should be in accordance with their instructions and the rules of the relevant procedures.
(2) The strength and tightness of the valve device should be tested. 20% of low-pressure valves, 100% of unqualified valves; Medium and high pressure valves should be 100% viewed.
(3) During the experiment, the orientation of the valve device should be in the direction of simple viewing.
(4) For valves in the form of welded connections, cone seals or O-ring seals can be used for pressure testing when the pressure test is not possible with the slap plate.
(5) During the hydraulic test, the valve air should be swept away as much as possible.
(6) During the experiment, the pressure should be gradually increased, and it is not allowed to increase the pressure sharply and suddenly.
(7) The strength test and tightness test generally last for 2-3min, and important and special valves should last for 5min. The experimental time of small-diameter valves can be correspondingly shorter, and the experimental time of large-caliber valves can be correspondingly longer. During the experiment, the experimental moment can be extended if in doubt.
(8) The throttle valve shall not be tested for the tightness of the seal, but shall be tested for strength and the tightness test at the packing and gasket.
(9) In the pressure test, the closing force of the valve only allows a person's normal physical strength to close; Afterburner (except for torque wrenches) with levers and the like is not allowed, and when the diameter of the handwheel is greater than 320mm, two people are allowed to close together.
(10) The valve with the upper seal should take out the packing material for the sealing test, and check whether there is leakage after the upper seal is closed. When using gas for experiments, the metal stamping is filled with water in the stuffing box. When doing packing tightness experiments, the upper seal is not allowed to be in a dense position.
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