As a key control component in fluid transportation systems, the sealing performance of valves directly affects the safety, stability, and environmental compliance of the system. In industries with high operating conditions such as petrochemicals, power, metallurgy, and water treatment, valve leakage is a common and significant operational hazard. It can cause medium loss in mild cases and serious accidents such as equipment damage, personnel poisoning, or explosions in severe cases. This article systematically analyzes the main causes, typical manifestations, treatment methods, and preventive measures of valve internal and external leakage, and proposes feasible engineering suggestions based on on-site experience to help enterprises achieve intrinsic safety management of valve systems.

1、 Reasons for valve leakage and quick handling

Valve internal leakage refers to the leakage of medium through the sealing pair after the valve is closed, mainly caused by the following reasons:

Common reasons:

Sealing surface damage

Particle erosion (such as sand particles, welding slag)

Corrosion caused by corrosive media (metal corrosion, aging of soft seals)

Long term wear and tear or cracking

Closing not in place

Manual not tightened, actuator not in place

Valve stem stuck, foreign objects blocking the sealing surface (such as rust, scaling)

● Quick processing:

Grind the sealing surface and replace the aging sealing components

Calibrate the execution mechanism to ensure complete closure

Install filters to block impurities

Use fluorine lined, ceramic or corrosion-resistant alloy sealing structures in corrosive media environments

2、 Types of valve leakage and repair measures

Valve leakage often occurs in areas such as packing boxes, flange connections, and valve cover welds, manifested as visible leakage or dripping.

● Leakage of stuffing box

Reason: Aging/wear of packing, loose gland, scratched or corroded valve stem.

Countermeasure: Tighten the gland bolts evenly, replace the packing in a timely manner, polish or replace the valve stem.

● Flange connection leakage

Reason: Loose bolts, improper selection of gaskets, and sand hole cracks in the valve body.

Countermeasure: Re tighten in diagonal order, replace the adapter gasket, and if necessary, weld or replace the valve.

● Valve cover or weld leakage

Reason: Casting defects, poor welding, and temperature and pressure fluctuations leading to cracking.

Countermeasure: Shutdown for replacement or repair, strengthen non-destructive testing of welds and incoming acceptance.

3、 Leakage prevention measures: proactive maintenance and systematic matching

To reduce the risk of leakage, control should be strengthened throughout the entire process from design, selection, installation to operation.

● Regular maintenance and inspection

Check the packing compression force and the integrity of the sealing pair;

Timely replace vulnerable parts such as seals, O-rings, gaskets, etc.

● Reasonably select and match working conditions

Prioritize the use of metal sealed globe valves in high-temperature environments;

Fluorine lined valves and Hastelloy seals should be used in highly corrosive environments;

It is recommended to choose ball valves for high-frequency switches; Low frequency long-term closure of preferred gate valves.

Install a filter at the front end of the pipeline

Effectively block rust, scaling, and particulate impurities inside the pipeline;

Reduce the probability of scratches and blockages on the sealing surface.

● Pressure test before installation

All new valves should undergo shell strength and sealing performance tests;

Ensure that there is no leakage under the design pressure before it can be put into operation.

4、 Suggestions for emergency response to leaks

In case of system shutdown or sudden leakage, temporary emergency measures should be taken:

Use metal repair agents or sealants to seal leaks;

Using leak proof clamps and sealing gaskets for external sealing;

For leaks of highly toxic, high-pressure, and flammable media, the system should be immediately isolated and professional personnel should be coordinated for disposal;

Temporary repairs should be marked with warning information and promptly replaced or shut down for thorough repairs afterwards.

5、 Building a valve safety loop to ensure zero leakage operation of the system

Valve leakage is not an occasional event, but a typical fault manifestation under the coupling of multiple factors. Only by establishing an operational strategy centered on "prevention first, maintenance as a supplement, and emergency controllability", combined with scientific selection, regular inspection, and precise repair, can the valve system achieve long-term, low-risk operation. Especially in special working conditions such as hazardous chemicals, high temperature and high pressure, the realization of intrinsic safety cannot be achieved without reliable control of every sealing point, which is precisely the new requirement of modern industrial safety management for valves.