Faced with so many valve classifications and such complex various working conditions, to choose a suitable valve product for the pipeline system installation, you should first understand the characteristics of the valve; secondly, you should master the steps and basis for selecting the valve; and then you should follow the selection Principles of valves used in the petroleum and chemical industries. The principle of selecting valves in the petroleum and chemical industries: the flow path is a straight-through valve, and its flow resistance is small, and it is usually selected as a shut-off and open medium valve; a valve that is easy to adjust the flow rate is used to control the flow rate; plug valves and ball valves are more suitable It is used for reversing and shunting; the sliding of the closing part along the sealing surface has a wiping valve [] suitable for medium with suspended particles.

01. Valves for shutting off and opening the medium

The flow channel is a straight-through valve, and its flow resistance is small, and it is usually selected as a valve for shut-off and open medium. The downward closing valve (stop valve, plunger valve) is less used because of its tortuous flow path and higher flow resistance than other valves. Where higher flow resistance is allowed

For occasions, a closed valve can be used.

02. Valves for flow control

Usually choose a valve that is easy to adjust the flow [] as the control flow. Downward closing valves (such as shut-off valves) are suitable for this purpose, because the size of its seat is proportional to the stroke of the closing member. Rotary valves (plug valves, butterfly valves, ball valves) and flexible

Curved body valves (pinch valves, diaphragm valves) can also be used for throttling control, but they are usually only applicable within a limited range of valve J diameters. The gate valve uses a disc-shaped gate to make a cross-cutting movement to the circular valve seat opening. It can only control the flow better when it is close to the closed position, so it is usually not used for flow control.

03. Valves for reversing and shunting

According to the needs of reversing and shunting, this kind of valve can have three or more channels. Plug valves and ball valves are more suitable for this purpose. Therefore, most of the valves used for reversing and splitting use one of the plug valves and ball valves. But in some cases,

For other types of valves, as long as two or more valves [] are properly connected to each other, they can also be used for reversing and shunting.

04. Valves for media with suspended particles

When there are suspended particles in the medium, it is suitable for valves with a wiping effect on the sliding of the closing part along the sealing surface. If the back and forth movement of the closing member to the valve seat is vertical, it may hold particles, so this kind of valve [door unless the sealing surface material can allow particles to be embedded, otherwise it is only suitable for basic clean media. Ball valves, plug valves, and butterfly valves have a wiping effect on the sealing surface during the opening and closing process, so they are suitable for use in media with surging particles.