Resolution of large diameter plate brake pressure testing method of pneumatic valve

with the development of science and technology, large diameter, high temperature resistant, resistant to high pressure plate brake pneumatic valve has been widely used. Due to micro resistance slowly-closing check pneumatic valve limited by equipment and try to pneumatic valve size, many large diameter flat brake pneumatic valve cannot use press for hydrostatic test, therefore, according to the characteristics of the pneumatic valve pressure testing device is designed. Pneumatic valve

flat brake
a, pressure testing method of large diameter plate brake pneumatic valve butterfly check in testing the hydraulic pneumatic valve, generally USES the bolt blind plate method, through the bolt pre-tightening force make the gasket produces compression forming sealing absorption solution, in order to realize the import and export of pneumatic valve seal below. Under the action of applied pressure F, signs of initial amount of compression for the aerodynamic lift check valve to the clamp. When the blind plate under internal pressure, signature by relaxing the springback, signs of compressed volume decreases, and when signs appear relaxed to a certain degree of leakage, the seal I curve reflects this clamping force on the minimum needed to seal in production, swing check pneumatic valve as long as reasonable choice gasket, in the case of blind flange rigid meet seal is easy to meet the minimum clamping force.
but in actual production, because of a shortage of blind flange rigid, in the end face of the pressure under the action of excessive deformation, the deformation of bolt looseness, API cast steel check pneumatic valve American standard gasket compression excessive amount of rebound, the gasket sealing pressure is reduced, thus forming a seal leakage test failures. In order to realize the safety and reliability of the hydraulic pressure test, usually by raising the blind flange rigidity, choose to achieve good sealing washer. But for large diameter high pressure pneumatic valve pressure testing, unlimited to improve blind flange rigidity, high quality packing, will increase the cost of production in the process of implementing, there are big limitations.

2, analysis in the process of pressure test, aerodynamic lift check valve force F F = PS blind flange end face the pressure formula shows that the pressure test to determine the circumstances, it is only through the structure to reduce transverse stress area, lift check on the pneumatic valve to achieve reduce the pressure of the end. When the transverse pressure decreases, and the minimum clamping force gasket also decreases, and accordingly to the blind flange rigid requirements also corresponding reduced. Import and export by nominal diameter mm, mm diameter bottom pneumatic valve pneumatic valve as an example for analysis. According to the formula to test the blind plate force F = KN. As the conventional method using A steel circular rigid, h = mm, the thickness of the radius R = mm, hydraulic pneumatic valve elastic modulus E = water level control. Multiplied by time Fang Zhao PASCAL, carries on the rigid core. Known from the analysis of mechanics, the blind plate can meet the strength and rigidity requirements needed for pressure testing, hydrostatic test can't be. Improve the problems of insufficient rigidity for pressure testing device, lie made amphibious spherical check pneumatic valve is done to the structure improvement. Change pressure blind flange to test the body, by testing the body reduce transverse stress area, so as to reduce the pressure of face, and to reduce the gasket pre-tightening force, to achieve reliable safety of hydraulic pressure test. The new test device to check blind plate stiffness.
the improved testing device through actual use, the micro resistance slowly-closing butterfly check pneumatic valve has good effectiveness, to solve the problem of large diameter high pressure pneumatic valve hydraulic test. （ According to the joint pneumatic valve website)