Valve selection according to flow characteristicsDoor
The shape of the opening and closing parts of the valve and the flow channel of the valve make the valve have certain flow characteristics. This must be taken into account when selecting a valve.
(1) Valves for cutting off and connecting media
Usually choose a valve with a small flow resistance and a straight-through flow path. Such valves include gate valves, globe valves, and plunger valves. The downward closed valve is rarely used because the flow path is tortuous and the flow resistance is higher than other valves. However, closed valves can also be used where higher flow resistance is allowed.
(2) Valves for flow control
Usually choose a valve that is easy to adjust the flow. Such as regulating valves, throttle valves, and plunger valves, because the size of its valve seat is proportional to the stroke of the opener. Rotary (such as plug valves, ball valves, butterfly valves) and flexural (pinch valves, diaphragm valves) valves can also be used for throttling control, but usually only within a limited range of valve diameters. In most cases, people usually change the shape of the valve disc of the globe valve for throttling. It should be pointed out that it is extremely unreasonable to change the opening height of the gate valve or globe valve to achieve the throttling effect. Because the flow rate of the medium in the pipeline is very high under the throttling state, the sealing surface is easily washed and worn, and the cutting and sealing effect is lost. Similarly, it is unreasonable to use a throttle valve as a cutting device.
(3)Valve for reversing flow
According to the needs of reversing and diverting, this valve can have two or more channels, and it is suitable for choosing plug valves and ball valves. Most of the valves for reversing and shunting use this type of valve. In some cases, other types of valves, with two or more properly connected to each other, can also be used for reversing and diverting media.
(4) Valves for media with suspended particles
If the medium contains suspended particles, it is more suitable to use a valve whose opening and closing parts slide along the sealing surface with a wiping effect, such as a flat gate valve.