Changsha Zoomlian Pump Co., Ltd. 长沙中联泵业股份有限公司

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    What should I do if the valve of a chemical pump is leaking?

    Publication Date:

    2026-01-05

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    In chemical pump systems, valves are extensively used under harsh operating conditions. Valve external leakage not only affects the efficiency of medium transportation but can also cause environmental pollution and even lead to safety incidents such as fires and explosions. Therefore, the sealing performance of valves is one of the key indicators for assessing their quality. External leakage primarily occurs at two major areas: the valve stem packing and the valve bonnet gasket. Internal leakage, on the other hand, often happens at the gate. By adopting scientifically sound structural designs and following standardized operating procedures, the risk of external leakage can be effectively reduced. Below, we present information from a chemical pump manufacturer. Changsha Zhonglian Pump Industry In conjunction with industry technical standards, provide a detailed description of the prevention and control measures for valve leakage in chemical pumps.

     

     

    1. Optimization of Valve Bonnet Gasket Sealing (Select and Match According to Caliber)

    Large-diameter valve ( DN ≥ 50mm ): For valve types such as gate valves, globe valves, and check valves, pressure-sealed bonnet structures are preferred. This structure features two core sealing surfaces: the contact surface between the bonnet and the ring gasket, and the contact surface between the ring gasket and the valve body. The dual-sealing design significantly enhances the valve’s pressure-resistant sealing performance. Some internationally advanced valve products feature a variable-angle arc transition at the contact surface between the ring gasket and the bonnet, creating a line-seal configuration that markedly improves sealing tightness. Additionally, certain products apply silver plating to the surface of the ring gasket and the corresponding sealing surface on the valve body; the excellent plasticity of silver helps fill microscopic pores on the sealing surfaces, further enhancing the sealing effectiveness at the bonnet-gasket interface. (Note: Although silver plating improves sealing performance, it is important to balance the increased processing difficulty of the ring gasket with cost control.)

    Small-caliber valve ( DN ≤ 40mm ): Gate valves, globe valves, check valves, ball valves, and plug valves (most of which feature a lower bonnet structure) typically employ flanged bonnet connections. These structures commonly use spiral-wound gaskets, which offer excellent elasticity and high resilience, ensuring stable sealing even under complex operating conditions. The matching bonnet seals adopt a box-type groove design, embedding the spiral-wound gasket into a dedicated groove at the junction between the bonnet and the valve body. This design not only prevents the gasket from losing stability due to excessive sealing specific pressure but also increases the resistance to medium leakage paths. Industrial practice has demonstrated that this sealing structure exhibits outstanding adaptability and reliability.

     

    II. Core Daily Preventive Measures for External Valve Leaks

    Select equipment strictly according to operating conditions: Based on the temperature, pressure, corrosivity, and other parameters of the medium being conveyed by the chemical pump, choose valve and gasket materials that correspond to the appropriate sealing grade, thereby avoiding sealing failure caused by material mismatches.

    Proper installation procedure: When installing the valve cover gasket, ensure that the contact surfaces are clean, free of impurities and scratches. Use evenly applied tightening torque for the bolts to prevent insufficient local pressure or excessive compression that could damage the seal.

    Regular Inspection and Maintenance: Regularly check the tightness of the valve stem packing and the sealing condition of the valve bonnet gasket. Replace the packing promptly if it shows signs of aging, or if the gasket is deformed or damaged. For valves operating under high-pressure and corrosive media conditions, shorten the inspection cycle and pay particular attention to monitoring the sealing areas for any signs of leakage.

    Optimize operating conditions: Avoid prolonged operation of valves under overpressure and overtemperature conditions, reduce media-induced erosion and corrosion of sealing surfaces, and extend the service life of sealing components.

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