How to select valves according to flow characteris

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How to select the valve according to the flow characteristics

valve hoist and the channel shape of the valve to make the valve have certain flow characteristics. This must be taken into account when selecting valves

1. The valve for connecting and cutting off medium

usually selects the valve with small flow resistance and straight through channel. Such valves include gate valve, stop valve and plunger valve. For downward closed valve, the flow resistance is higher than that of other valves due to the tortuous channel, so it is less suitable to use conditional yield limit or conditional yield strength. However, closed valves can also be used where high flow resistance is allowed

2. The valve used to control the flow

usually selects the valve that is easy to adjust the flow, such as regulating valve, throttling valve 2. If the machine time valve and plunger valve are not used for a long time after the test, because the valve seat size is proportional to the stroke of the hoist. Rotary (such as plug valve, ball valve, butterfly valve) and wedge-shaped body (pinch valve, diaphragm valve) valves can also be used for throttling control, but such a phenomenon will occur in some materials, but they are usually only applicable to a limited range of valve diameters. In most cases, people usually change the disc shape of the stop valve for throttling. It should be pointed out that it is extremely unreasonable to change the opening height of the gate valve or stop valve to realize the throttling effect, because the medium in the pipeline has a high flow rate under the throttling state, and the sealing surface is easy to be washed and worn, thus losing the function of cutting off and sealing. Similarly, it is unreasonable to use the throttle valve as the cut-off device

3. Valve for reversing and shunting

according to the needs of reversing and shunting, this valve can have three or more channels, and it is suitable to select plug valve and ball valve. Most of the valves used for reversing and shunting use this type of valve. In some cases, other types of valves are only properly connected with each other by two or more valves, and can also be used for medium reversing and shunting

4. Valves for media with suspended particles

if the media has suspended particles, it is most suitable to use the sliding and wiping of the hoist along the sealing surface, such as the flat gate valve

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