Power plant as the main place of power production, the equipment and pipe network operation state will directly affect the production and transmission of power in the power plant of many equipments. Valve is one of the key components, the application of valve has a direct impact on the operation of pipe network. However, valve leakage often occurs in the process of production and operation of power plants in China. Long time leakage of valves will affect the production safety and economic benefits of the whole power plant. Therefore, this paper analyzes the valve leakage problem in power plants.

1. Valve Packing Leakage

Valves in the process of use will happen to relative motion between stem and packing. In the process of stem rotation, packing will loose and spill due to forces outside for a long time which not only include the valve rod rotation, also includes the valve using the environment factors, such as temperature, pressure, the influence of these factors. Under the joint action of their packing, their properties may be aging, loss of elasticity, and cause leakage problems in the process of using.

Ball Valve Packing

2. Flange Leakage

Flange leakage mainly refers to valve flange sealing performance problems. In general, the valve seal mainly through flange seal, With the pretension of the connecting bolt and the gasket, achieve enough sealing pressure, thus the fluid inside the pipeline and medium leakage, but in the actual after long time use, the valve flange leak problem could occur. Generally speaking, the main causes of valve leakage include insufficient sealing gasket pressure, bolt deformation or other human factors.

Flanged Ball Valve for Natural Gas

3. External Leakage of Valve Body

Valve leakage is the quality problems of the valve itself, mainly is the key parts of the valve. In the process of making the seal or performance deficiencies, such as its itself there is porosity, crack, and the body in the process of using, corrosion and scouring by liquid for a long time can lead to further expand these flaws, thus gradually cause leakage problems.