Valve leakage is a common problem in industrial production, which not only causes waste of raw materials and energy, but also may directly pollute the environment, and even lead to major safety accidents such as explosions and fires. Therefore, understanding the causes of valve leakage is crucial.
There are various reasons for valve leakage. Firstly, defects in the valve body and valve cover are one of the main causes of external leakage. If there are defects such as sand holes, loose structure, or slag inclusions in the valve body and valve cover during casting or forging, the medium may leak through these defects. In addition, the valve body and valve cover may also leak due to frost cracking in cold weather.
Secondly, leakage at the packing point is also a common cause of valve leakage. The main function of packing is to seal the gap between the valve stem and the valve body. If the packing is selected improperly, installed incorrectly, or aged and fails, the medium may leak along the gap between the packing and the valve stem. In addition, low precision of the valve stem, failure to tighten or damage the gland may also cause leakage at the packing.
Furthermore, leakage from the sealing surface cannot be ignored. The sealing surface is the key part to prevent medium leakage when the valve is closed. If the sealing surface is ground unevenly, damaged, or the material is selected improperly, an effective sealing line cannot be formed, resulting in medium leakage.
In addition, leakage at the connection of the sealing ring is also an important cause of valve leakage. If the sealing ring is not tightly rolled, the welding quality is poor, or the connecting threads and screws are loose, it may cause leakage at the sealing ring connection.
In summary, the main causes of valve leakage include defects in the valve body and cover, leakage at the packing, leakage at the sealing surface, and leakage at the connection of the sealing ring. To prevent valve leakage, we need to start from multiple aspects such as material selection, design, manufacturing, installation, and maintenance to ensure that the sealing performance of the valve meets the requirements. At the same time, regular inspection and maintenance of valves are also effective measures to prevent leakage.
