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Pneumatic control valve leakage form and reason


Release time:

2022-02-12

Wuxi Xinming automatic control valve industry to introducePneumatic control valveThe form and cause of the leak. General requirements for the correct installation of pneumatic control valves. First of all, during the installation process, the regulating valve is required to be upright and perpendicular to the horizontal pipeline, with permanent supports at the front and rear. Secondly, adjust the installation position of the regulating valve, leaving enough maintenance operation platform for future maintenance and calibration.

Pneumatic control valve leakage form and reason

Wuxi Xinming automatic control valve industry to introducePneumatic control valveThe form and cause of the leak.
General requirements for the correct installation of pneumatic control valves. First of all, during the installation process, the regulating valve is required to be upright and perpendicular to the horizontal pipeline, with permanent supports at the front and rear. Secondly, adjust the installation position of the regulating valve, leaving enough maintenance operation platform for future maintenance and calibration. Third, there should be enough space for the upper and lower control valves. On the one hand, the installer should remove the valve plug and flange of the control valve. Four is to do a good job of anti-vibration measures and small pressure gauge. Fifth, the regulating valve should be inspected and calibrated before installation to ensure the quality of the regulating valve and clean the pipeline.
Control valve installation need to consider safety issues. First of all, when installing the regulating valve, protective measures should be taken to protect the safety of personnel and equipment. Secondly, after the control valve is cut off, there will often be a certain pressure residue inside. During this process, adequate decompression measures should be taken to ensure safety. Third, ifPneumatic control valveIf contact with liquid is required, a restrictor valve needs to be installed to prevent serious damage to the equipment and the entire system when the flow rate is too fast. Fourth, thermal insulation measures should be taken when installing steam pipelines. Fifth, in order to prevent serious pressure fluctuations, pipeline buffers should also be installed.
The leakage of the packing, during the operation and use of the valve, there is relative movement between the valve stem and the packing, including rotation and axial movement. As the number of switching increases, the number of relative movements also increases, as well as the influence of temperature, pressure and fluid medium characteristics. Valve packing is a very leakage prone component. This is due to the gradual weakening of the contact pressure of the filler, the aging of the filler itself and the loss of elasticity. At this time, the pressure medium will leak outward along the contact gap between the packing and the valve stem, blow away part of the packing, and flush the valve stem out of the groove for a long time, thereby expanding the leakage.
Flange leakage, the valve flange seal mainly depends on the preload of the connecting bolt, through the gasket to achieve sufficient sealing pressure, to prevent the leakage of the sealed pressure fluid medium. There are many reasons for its leakage. The pressing force of the sealing gasket is insufficient, the roughness of the joint surface does not meet the requirements, the deformation of the gasket and the mechanical vibration will cause the sealing gasket and flange joint surface to loosen and leak. In addition, due to the poor sealing of the flange surface, bolt deformation or elongation, gasket aging, reduced resilience and cracking will also cause leakage. Flange leakage also has human factors that cannot be ignored. For example, the installation deviation of the gasket makes the local sealing pressure insufficient, the tightening force is too large, and the design range of the gasket is exceeded. When the flange is fastened, the force is uneven or the core line of the two flanges Offset, resulting in false tightening and easy leakage.
Leakage and valve body reasons, valve body leakage is mainly caused by casting or forging defects in the valve production process, such as sand holes, pores, cracks, etc., as well as fluid medium erosion and cavitation is also a common factor leading to valve body leakage.
The above is Wuxi Xinming automatic control valve industry to introduce the relevant content.





 

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