【Valve Knowledge】Valve Inspection, Repair and Lifespan

Valve Inspection

Valve inspection is extremely important, as it determines whether the valve can operate normally and safely. Valve inspection mainly includes the following aspects:

Check model and specifications: Carefully check whether the valve model and specifications meet the requirements of the drawings.
Flexibility check: Check whether the valve stem and valve disc are flexible to open, and whether there is any stuck or skew.
Integrity check: Check whether the valve is damaged, and whether the threads of the threaded valve are straight and intact.
Connection check: Check whether the valve seat and valve body are firmly connected, and whether the connection between the valve disc and valve seat, valve cover and valve body, and valve stem and valve disc is intact.
Material adaptability check: Check whether the valve gasket, packing and fasteners (bolts) are suitable for the requirements of the working medium.
Sealing check: Remove the port cover and check the sealing degree. The valve disc must be closed tightly. For low-pressure, medium-pressure and high-pressure valves, strength tests and tightness tests are also required.

Valve repair

Valve repair is equally important. When a valve fails or is damaged, timely repair can avoid greater losses. Valve repair mainly includes the following aspects:

Determine the cause of the leak: Before repairing the valve leak, it is crucial to determine the cause of the leak. Common causes of leaks include valve aging, loose connections, damaged gaskets, and broken valves.
Prepare tools and materials: Prepare tools and materials such as wrenches, screwdrivers, sealing tape, new gaskets, pipe clamps, cleaning cloths, sandpaper, and waterproof glue.
Turn off the water source: Before starting the repair, make sure that the relevant water source has been turned off to avoid unnecessary losses during the repair process.
Tighten the connection: If you find that the connection is loose, you can try to tighten the connection. If the leak problem is solved, it may be just a simple loose connection problem.
Replace the gasket: If tightening the connection does not solve the problem, you may need to replace the gasket. This includes steps such as disassembling the valve, removing the old gasket, cleaning the sealing position, placing a new gasket, and reinstalling the valve.
Apply sealing tape or waterproof glue: For smaller cracks or poorly sealed areas, you can use sealing tape or waterproof glue to repair them.
Replace the entire valve: If the valve itself is found to have physical damage, such as cracks or severe corrosion, you may need to replace the entire valve.

Valve life

The life of the valve is affected by many factors, including the type of valve, material, usage conditions, and maintenance. Here are some common valve lifespans and their influencing factors:

Globe valve: The service life generally ranges from 3 to 10 years, affected by factors such as materials, usage environment, working pressure and temperature, and maintenance.
Ball valve: The service life is usually around 10 to 20 years, affected by factors such as the corrosiveness and viscosity of the medium, operating frequency, installation location, and material.
Gate valve: The service life is generally around 20 years, but the service life will be reduced accordingly in harsh environments (such as high temperature and high pressure, corrosion, frequent vibration, etc.).
Water pipe switch valve: The service life is generally around 15 years, which is also affected by factors such as material, environment, and frequency of use.
Nuclear power valves: The service life is usually expressed in years of use. For example, the nuclear power valves in the United States and Germany guarantee a service life of 40 years, the United Kingdom is 30 years, and Japan is 30-40 years.

In addition, the method of determining the service life of foreign valves also includes expressing it by the number of switches. The number of switches of different valves under different working conditions may not be the same, so the life of the valve cannot be judged simply by the number of switches. Only when the working conditions are the same and the use or test methods are the same, the more the number of switches or the longer the use time can be considered a long life.