Most of the media in chemical production equipment have the characteristics of high toxicity, flammability, explosiveness and strong corrosiveness. The working conditions are complex and harsh, and the operating temperature and pressure are high. Once the valve fails, the lighter will cause the medium to leak, and the heavyer will cause the device to stop. Stop production and even cause serious accidents. Therefore, the scientific and reasonable selection of industrial valves can not only reduce the construction cost of the device, but also ensure the safe operation of production.

Key points of industrial valves selection guide

1. Clarify the purpose of the valve in the equipment or device

Determine the working conditions of the valve: the nature of the applicable medium, the working pressure, the working temperature, and the operation control method.

2. Correctly select the types of industrial valves

The correct choice of valve type is based on the designer's full grasp of the entire production process and operating conditions. When selecting the valve type, the designer should first grasp the structural characteristics and performance of each valve.

3. Determine the end connection of the valve

Among threaded connections, flange connections, and welded end connections, the first two are the most commonly used. Threaded valves are mainly valves with a nominal diameter below 50mm. If the diameter is too large, it will be difficult to install and seal the connection.

Flange-connected valves are more convenient to install and disassemble, but they are heavier and more expensive than screw-connected valves, so they are suitable for pipe connections of various diameters and pressures.

Welding connection is more reliable than flange connection under more severe conditions. However, it is more difficult to disassemble and reinstall the valve connected by welding, so its use is limited to the occasions that can usually operate reliably for a long time, or where the use conditions are harsh and the temperature is high.

4. Selection of industrial valves material

When selecting the material of the valve housing, internal parts and sealing surface, in addition to considering the physical properties (temperature, pressure) and chemical properties (corrosiveness) of the working medium, the cleanliness of the medium (with or without solid particles) should also be grasped. In addition, refer to the relevant regulations of the country and the user department.

The correct and reasonable selection of the valve material can obtain the most economical service life and the best performance of the valve. The valve body material selection sequence is cast iron-carbon steel-stainless steel, and the sealing ring material selection sequence is rubber-copper-alloy steel-F4.

5. Other

In addition, the flow rate and pressure rating of the fluid flowing through the valve should also be determined, and the appropriate valve should be selected using existing information (such as valve product catalogs, valve product samples, etc.).

Commonly used industrial valves selection instructions

1. Selection instructions for industrial gate valves

In general, gate valves should be preferred. In addition to suitable for steam, oil and other media, gate valves are also suitable for media containing granular solids and high viscosity, and are suitable for valves in venting and low vacuum systems. For media with solid particles, the valve body of the gate valve should have one or two purge holes. For low-temperature media, low-temperature dedicated gate valves should be used.

               

Gate Valve BS 5163 Flanged Resilient NRS, Type B (Z45XB), PN10/16

               

Flanged Gate Valve OS&Y Gate Valve (Z41X), UL/FM Approved

2. Instructions for selection of globe valve

The stop valve is suitable for pipelines that do not require strict fluid resistance, that is, pipelines or devices with high temperature and high pressure medium that do not consider pressure loss, and are suitable for medium pipelines such as steam with DN<200mm.

Small valves can choose globe valves, such as needle valves, instrument valves, sampling valves, pressure gauge valves, etc.

The stop valve has flow adjustment or pressure adjustment, but the adjustment accuracy is not high, and the pipe diameter is relatively small, it is better to use a stop valve or a throttle valve.

For highly toxic media, a bellows-sealed globe valve should be used; however, the globe valve should not be used for media with high viscosity and media containing particles that are easy to precipitate, nor should it be used as a vent valve or low vacuum system valve.

3. industrial ball valves selection instructions

The ball valve is suitable for low temperature, high pressure and high viscosity medium. 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.

The full-channel ball valve is not suitable for flow adjustment, but it is suitable for occasions that require fast opening and closing, which is convenient for emergency shutdown of accidents; usually in strict sealing performance, wear, necking passage, rapid opening and closing action, high pressure cutoff (large pressure difference), In pipelines with low noise, vaporization, small operating torque and low fluid resistance, ball valves are recommended.

The ball valve is suitable for light structure, low pressure cut-off, and corrosive media; the ball valve is also the most ideal valve for low temperature and cryogenic media. For the piping system and device of low temperature media, it is better to use the low temperature ball valve with bonnet.

When selecting a floating ball valve, its seat material should bear the load of the ball and the working medium. Large-caliber ball valves require greater force during operation.

The 200mm ball valve should use worm gear transmission; the fixed ball valve is suitable for larger diameter and higher pressure occasions; in addition, the ball valve used for the process of highly toxic materials and flammable medium pipelines should have a fireproof and antistatic structure.

4. Description of throttle valve selection

The throttle valve is suitable for occasions where the medium temperature is low and the pressure is high, and it is suitable for the parts that need to adjust the flow and pressure. It is not suitable for the medium with high viscosity and containing solid particles, and it is not suitable for the isolation valve.

5. Description of plug valve selection

The plug valve is suitable for occasions that require fast opening and closing. It is generally not suitable for steam and higher temperature media, for lower temperature and high viscosity media, and also for media with suspended particles.

6. industrial butterfly valves selection instructions

Butterfly valve is suitable for large diameter (such as DN﹥600mm) and short structure length, as well as occasions where flow adjustment and fast opening and closing are required. Generally used for water, oil and compressed air at a temperature of 80℃ and a pressure of 1.0MPa Medium: Because the pressure loss of butterfly valve is relatively large compared with gate valve and ball valve, butterfly valve is suitable for pipeline system with less strict pressure loss requirements.

               

Wafer Style Butterfly Valve BS EN 593 (D71X4, D371X4), PN10/16

               

Lug Butterfly Valve BS EN 593 (D71XL4, D371XL4), PN10/16

7. Check valve selection instructions

Check valves are generally suitable for clean media, not for media containing solid particles and high viscosity. When DN≤40mm, lift check valve should be used (only allowed to be installed on horizontal pipelines); when DN=50～400mm, swing check valve should be used (can be installed on both horizontal and vertical pipelines, If installed on a vertical pipeline, the flow direction of the medium should be from bottom to top).

When DN≥450mm, buffer check valve should be used; when DN=100～400mm, wafer check valve can also be used; swing check valve can be made into high working pressure, PN can reach 42MPa, It can be applied to any working medium and any working temperature range according to the different materials of the shell and seals.

The medium is water, steam, gas, corrosive medium, oil, medicine, etc. The working temperature range of the medium is between -196～800℃.

               

Silent Check Valve (HC41X), PN10/16

               

Spring Check Valve EN 12334 Rubber Disc Swing Check H44J PN10/16

8. Diaphragm valve selection instructions

Diaphragm valve is suitable for oil, water, acid medium and medium containing suspended solids whose working temperature is less than 200℃ and pressure is less than 1.0MPa. It is not suitable for organic solvent and strong oxidant medium.

Weir diaphragm valves should be selected for abrasive granular media, and the flow characteristics table of weir diaphragm valves should be referred to for selection of weir diaphragm valves; straight-through diaphragm valves should be selected for viscous fluids, cement slurry and sedimentary media; diaphragm valves are not suitable for vacuum pipes except for specific requirements Road and vacuum equipment.

Hope that this article is useful for you. If you are searching for the reliable industrial valves manufacturers, you can visit Shenzhen Mech Valve Trading Co., Ltd. Established in 1961, we are the large-scale enterprise group with advanced technology and equipment and strong comprehensive strength, known for its complete range of products, large producing capacity, high quality and strong R&D strength.