How to detect valve leakage

Valves are very important control elements in industrial production systems, widely used in fields such as oil, chemical, power, natural gas, and more. Their main functions include regulating the flow of media, cutting off or conducting pipeline systems, and so on. However, due to reasons such as long-term operation, wear, corrosion, or improper installation, valves are prone to leakage problems. Valve leakage not only causes energy waste and environmental pollution but may also trigger safety accidents. Therefore, timely and effective detection of valve leakage is of great significance.

One, Common Causes of Valve Leakage

Valve leakage is usually divided into two forms: external leakage and internal leakage. External leakage refers to the leakage of medium from the external sealing parts such as the valve body and cover, gasket, etc.; internal leakage refers to the existence of medium passing through the valve in the closed state, usually caused by the poor sealing between the valve disc and seat. Common causes include: wear of the sealing surface, impurities stuck, improper operation, material aging, etc.

Two, Detection Methods of Valve Leakage

1. Visual and Auditory Inspection
The most basic detection method is to observe with the naked eye whether there is any liquid or gas leakage, or to judge whether there is an abnormal air flow sound through hearing. This method is suitable for gas medium leakage or obvious leakage, but is not sensitive to small leaks.

2. Bubble Detection Method
Apply soap solution to the suspected leakage area. If there is gas leakage, bubbles will form. This method is simple to operate, low in cost, widely used in the field, and suitable for detection of pneumatic systems and low-pressure systems.

3. Ultrasonic Detection Method
Using ultrasonic instruments to detect the high-frequency sound waves generated by leakage. This method has a high sensitivity, can detect small leaks, and can achieve non-contact detection, especially suitable for high temperature, high pressure, or difficult-to-access valves.

4. Infrared Thermal Imaging Method
Judging the leakage situation by observing the temperature change through an infrared imaging instrument. If there is a leakage in the valve, it will cause local temperature abnormalities, which is suitable for high-temperature media or occasions with thick insulation layers.

5. Pressure Test Method
After isolating the upstream and downstream of the valve, pressure is applied to the pipeline section where the valve is located, and the pressure change is observed after maintaining it for a period of time. If the pressure drops, there may be a leakage. This method is suitable for use during shutdown and maintenance.

6. Gas Detector Detection
Use flammable gas or toxic gas detectors to scan around the valve for leakage detection, which is suitable for the leakage detection of easily flammable and explosive media such as natural gas and liquefied petroleum gas.

Three, Prevention and Maintenance Suggestions

To reduce the occurrence of valve leakage, enterprises should establish a sound valve maintenance system and carry out regular inspections and status monitoring. At the same time, they should select quality-assured valve products suitable for the working conditions and install and use them strictly according to the operational procedures. For key valve parts, it is recommended to install an on-line monitoring system to achieve intelligent management.

Four, Conclusion

The detection of valve leakage is not only related to the safe operation of equipment, but also directly affects the production efficiency and environmental protection indicators of the enterprise. Through scientific detection methods and effective preventive measures, the risk of leakage can be significantly reduced, ensuring the stable operation of the production system. In the future, with the development of sensor technology and artificial intelligence, valve leakage detection will develop towards automation and intelligence, providing a stronger guarantee for industrial safety.