27

2020

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02

Principles for selecting valves in the petroleum and chemical industries

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Faced with so many valve classifications and such complex various working conditions, to choose the most suitable valve product for pipeline system installation, you should first understand the characteristics of the valve; secondly, you should master the steps and basis for selecting the valve; thirdly, you should follow the selection of oil , Principles of valves used in the chemical industry. Principles for selecting valves in the petroleum and chemical industries: valves with straight-through flow channels have small flow resistance and are usually selected as valves for shut-off and opening media; valves that are easy to adjust the flow are used for flow control; plug valves and ball valves are more suitable It is used for reversing and diverting flow; the closing member slides along the sealing surface and has a wiping effect. It is most suitable for media with suspended particles.

Faced with so many valve classifications and such complex various working conditions, to choose the most suitable valve product for pipeline system installation, you should first understand the characteristics of the valve; secondly, you should master the steps and basis for selecting the valve; thirdly, you should follow the selection of oil , Principles of valves used in the chemical industry. Principles for selecting valves in the petroleum and chemical industries: valves with straight-through flow channels have small flow resistance and are usually selected as valves for shut-off and opening media; valves that are easy to adjust the flow are used for flow control; plug valves and ball valves are more suitable It is used for reversing and diverting flow; the closing member slides along the sealing surface and has a wiping effect. It is most suitable for media with suspended particles.

 

  1. Valves for shutting off and opening media

    The valve with a straight-through flow path has a small flow resistance and is usually selected as a valve for shutting off and opening the medium. Downward closing valves (stop valves, plunger valves) are rarely used due to their tortuous flow paths and higher flow resistance than other valves. In situations where higher flow resistance is allowed, closed valves can be selected.

  2. Valves used to control flow

    Valves that are easy to adjust the flow are usually selected for flow control. Downward-closing valves (such as globe valves) are suitable for this purpose because their seat size is directly proportional to the stroke of the closing member. Rotary valves (plug valves, butterfly valves, ball valves) and deflection valves (pinch valves, diaphragm valves) can also be used for throttling control, but usually only within a limited valve diameter range. The gate valve uses a disc-shaped gate plate to make a transverse movement to the circular valve seat opening. It can better control the flow only when it is close to the closed position, so it is usually not used for flow control.

  3. Valve for reversing and diverting flow

    This valve can have three or more channels depending on the need for reversing the flow. Plug valves and ball valves are more suitable for this purpose. Therefore, most valves used for reversing and diverting flow choose one of these valves. However, in some cases, other types of valves can also be used for reversing and diverting flow as long as two or more valves are properly connected to each other.

  4. Valves for media with suspended particles

    When there are suspended particles in the medium, it is most suitable for valves whose closing parts slide along the sealing surface with a wiping effect. If the back-and-forth movement of the closing member against the valve seat is vertical, particles may be trapped. Therefore, this type of valve is only suitable for basically clean media unless the sealing surface material can allow embedded particles. Ball valves, plug valves, and butterfly valves all have a wiping effect on the sealing surface during the opening and closing process, so they are suitable for use in media with suspended particles.

    At present, whether in the pipeline system of petroleum, chemical industry, or other industries, the application, operating frequency and service of valves are ever-changing. To control or eliminate even small leaks, the most important and critical equipment still relies on valves. The ultimate control of the pipeline is the valve. The service and reliable performance of the valve in various industries are unparalleled.