How to prevent seat and gate leakage in gate valves?

Gate valve seat and gate leakage is one of the most common issues encountered during installation and maintenance. This type of leakage generally falls into two categories:

Sealing surface leakage

Seal ring root leakage

Proper preventive measures can significantly reduce the risk of leakage and ensure the long-term performance of the valve.

1.Inspection and Precision of Sealing Surfaces

Before installation or maintenance, it is crucial to check the precision of the contact sealing surface between the seat and gate. The sealing surface must be at least lapped and polished. If the surface appears excessively rough, the valve seat should be removed and reprocessed through grinding.

Additionally, check for pitting, indentations, sand holes, or cracks on the sealing surface. If any defects are detected, the gate or seat must be replaced to ensure a proper seal.

gate valves

2.Checking the Elasticity of Spring-Loaded Seats

For spring-loaded valve seats, the elasticity of the compression spring should be tested. If the spring has weakened over time, it must be replaced to maintain adequate sealing pressure.

3.Gate and Stem Connection Adjustment

The T-joint connection between the gate and stem should not be excessively loose. A loose connection can cause the gate to tilt during closure, leading to improper sealing. In such cases, the gate must be removed and adjusted to the optimal fit to ensure even pressure distribution.

gate valve

4.Cleaning Internal Debris Before Installation

During installation, foreign objects such as weld slag, iron filings, and other impurities can easily enter the valve body. If these contaminants are not properly cleaned, they may prevent the gate from closing completely, leading to leakage. The valve body must be thoroughly cleaned before installation to remove any debris. If a leak occurs due to foreign objects, the valve must be disassembled and cleaned again.

5.Proper Installation of the Valve Seat

When installing the valve seat, a special installation tool should be used to ensure precise positioning. If the threaded seat is not fully tightened to the expected depth, leakage may occur at the valve seat interface. In such cases, the seat must be reinstalled correctly using the appropriate tools to achieve a tight and secure fit.

Preventing seat and gate leakage in gate valves requires proper surface preparation, component inspection, correct installation techniques, and thorough cleaning. By following these preventive measures, valve reliability and operational efficiency can be significantly improved, reducing the risk of unexpected failures in industrial applications.

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