What are the leakage of explosion-proof electric ball valve?

Leakage of explosion-proof electric ball valve often occurs on packing, flange seal and valve body. Long term leakage of the valve will lead to corrosion of the valve stem and flange sealing surface, resulting in scrapping of the electric ball valve. Consume more, increase cost and reduce economic benefits, except for the loss of medium and fluid. Accelerate the corrosion speed of plant equipment, shorten the service life, pollute the surrounding environment, damage the power production and do harm to people’s health. If the medium liquid is toxic, flammable, explosive and easy to corrode, poisoning, fire, explosion and other accidents are likely to occur. Leakage seriously threatens production safety and increases unplanned shutdown accidents. Below, some reasons for leakage of explosion-proof electric ball valve, how to plug and how to repair and maintain are introduced for reference.

1. Leakage form and cause of explosion-proof electric ball valve
The relative movement between the valve stem and the packing, including rotational movement and axial movement, is during the operation and use of the electric ball valve. The temperature, pressure and characteristics of the fluid medium will also increase the number of relative movements with the increase of the number of switches. Electric ball valve packing is more likely to leak. This is due to the gradual weakening of the packing contact pressure, aging of the packing itself, loss of elasticity and other reasons. At this time, the pressure medium leaks outward along the contact gap between the packing and the valve stem, and part of the packing is blown away. The valve stem is flushed out of the groove for a long time, and the leakage expands.

2. Flange leakage
The flange seal of explosion-proof electric ball valve provides sufficient sealing specific pressure to prevent leakage of sealing pressure fluid medium, which mainly depends on the pre tightening force of connecting bolts and washers. There are many reasons for leakage. Air leakage on the joint surface of sealing gasket and flange is due to insufficient gasket pressure, poor roughness of joint surface, deformation of gasket or mechanical vibration. In addition, due to the deformation and elongation of the bolts, the flange surface may leak due to insufficient sealing, which is caused by the deterioration of the gasket over time, elastic loss and cracking. In addition, the flange leakage also has human factors that can not be ignored, such as offset of sealing gasket, insufficient local sealing pressure, excessive tightening force, limited design of sealing gasket and uneven stress. It may also be due to the deviation of orchid center line, resulting in leakage of two methods during flange tightening, thus leading to wrong tightening.

3. Valve body leakage and causes
The leakage of explosion-proof electric ball valve body is mainly due to the erosion and cavitation of fluid medium caused by casting or forging defects in the process of valve manufacturing, such as sand holes, air holes and cracks. This is also a common cause of valve body leakage.