1. Selection instructions for gate valve

In general, gate valves should be preferred. Gate valves are not only suitable for media such as steam and oil, but also for media containing granular solids and high viscosity, and are suitable for valves in venting and low vacuum systems. For media containing solid particles, the gate valve body should have one or two purge holes. For low-temperature media, low-temperature dedicated gate valves should be selected.

2. Selection instructions for globe valve

Globe valves are suitable for pipelines that do not have strict requirements for fluid resistance, that is, pipelines or devices with little consideration for pressure loss, as well as high-temperature and high-pressure media. They are suitable for pipelines with DN<200mm for steam and other media. Small valves can choose globe valves, such as needle valves, instrument valves, sampling valves, pressure gauge valves, etc. Globe valves have flow or pressure regulation, but they do not require high regulation accuracy and the pipeline diameter is relatively small. Therefore, it is advisable to choose a globe or throttle valve. For highly toxic media, it is advisable to use a shut-off valve sealed with a corrugated pipe. However, globe valves should not be used for media with high viscosity and media containing particles that are prone to sedimentation, nor should they be used as vent valves or valves for low vacuum systems.

3. Selection instructions for ball valve

Ball valves are suitable for medium with low temperature, high pressure, and high viscosity. Most ball valves can be used in media with suspended solid particles, and can also be used in powder and granular media according to the sealing material requirements. Full channel ball valves are not suitable for flow regulation, but are suitable for situations that require quick opening and closing, facilitating emergency shutdown in accidents. Ball valves are usually recommended for pipelines with strict sealing performance, wear, shrinking channels, rapid opening and closing action, high pressure cutoff (large pressure difference), low noise, gasification phenomenon, low operating torque, and low fluid resistance. Ball valves are the most ideal valves for low-temperature and cryogenic media. For pipeline systems and devices with low-temperature media, it is advisable to choose low-temperature ball valves with valve covers. When selecting floating ball valves, the valve seat material should bear the load of the ball and working medium. Large diameter ball valves require significant force during operation, and ball valves with DN ≥ 200mm should use worm gear transmission. Fixed ball valves are suitable for larger diameters and higher pressure applications. In addition, ball valves used for highly toxic materials and combustible medium pipelines in the process should have a fireproof and anti-static structure.

4. Selection instructions for throttle valve

The throttle valve is suitable for occasions with low medium temperature and high pressure. It is suitable for areas that require flow and pressure regulation, and is not suitable for media with high viscosity and containing solid particles. It is not suitable as a shut-off valve.

5. Selection instructions for plug valve

Plug valves are suitable for situations that require quick opening and closing. It is generally not suitable for steam and high temperature media. It is suitable for medium with low temperature and high viscosity, as well as medium with suspended particles.

6. Selection instructions for butterfly valve

Butterfly valves are suitable for situations with larger diameters (such as DN>600mm) and short structural length requirements, as well as situations where flow regulation and fast opening and closing requirements are required. Generally used for media such as water, oil, and compressed air with a temperature ≤ 80 ℃ and a pressure ≤ 1.0MPa. Due to the relatively large pressure loss of butterfly valves compared to gate valves and ball valves, butterfly valves are suitable for pipeline systems with less stringent pressure loss requirements.

7. Selection instructions for check valve

Check valves are generally suitable for cleaning media and should not be used in media containing solid particles or high viscosity. When DN ≤ 40mm, it is advisable to use a lift check valve (only allowed to be installed on horizontal pipelines). When DN=50-400mm, it is advisable to use a swing lift check valve (which can be installed on both horizontal and vertical pipelines. If installed on vertical pipelines, the flow direction of the medium should be from bottom to top). When DN ≥ 450mm, buffer type check valves should be used. When DN=100-400mm, a wafer type check valve can also be selected. The swing check valve can be made into a high working pressure, with a PN of up to 42MPa. It can be suitable for any working medium and any working temperature range depending on the material of the shell and sealing parts. The medium is water, steam, gas, corrosive medium, oil products, drugs, etc. The working temperature range of the medium is between -196~800 ℃.

The application, operating frequency, and service of valves are constantly changing. To control or eliminate minor leaks, the most important and critical equipment is the valve. Learning to choose valves correctly is crucial.