02

2020

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04

How butterfly valve works

Author:


The butterfly valve is a valve that opens and closes by rotating the valve stem while driving the disc to rotate. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, mainly rotating the disc 90° for flow control. , when the disc reaches 90°, the valve is in a fully open state. At the same time, the angle of the disc can be changed to adjust the medium flow. It is generally installed in the diameter direction of the pipe. The butterfly valve and the valve stem themselves have no locking ability. In order to effectively adjust the flow rate, a worm gear reducer is required. A butterfly valve equipped with a worm gear reducer not only makes the butterfly valve self-locking, but also changes the operating performance of the butterfly valve and regulates the medium flow rate more accurately. .

The butterfly valve is a valve that opens and closes by rotating the valve stem while driving the disc to rotate. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, mainly rotating the disc 90° for flow control. , when the disc reaches 90°, the valve is in a fully open state. At the same time, the angle of the disc can be changed to adjust the medium flow. It is generally installed in the diameter direction of the pipe. The butterfly valve and the valve stem themselves have no locking ability. In order to effectively adjust the flow rate, a worm gear reducer is required. A butterfly valve equipped with a worm gear reducer not only makes the butterfly valve self-locking, but also changes the operating performance of the butterfly valve and regulates the medium flow rate more accurately. .

 

Butterfly valve characteristics:

  1. It has simple structure and small dimensions. Due to its compact structure, short structural length, small size and light weight, it is suitable for large diameters.

  2. The fluid resistance is small. When fully open, the effective circulation area of ​​the valve seat channel is large, so the fluid resistance is small.

  3. The opening and closing is convenient and fast, the adjustment performance is good, and the butterfly plate rotates 90 degrees. Both opening and closing can be completed. By changing the rotation angle of the butterfly plate, the flow rate can be controlled in stages.

  4. The opening and closing torque is small. Since the butterfly plates on both sides of the rotating shaft are basically equally affected by the medium and the torque is generated in opposite directions, opening and closing is less labor-intensive.

  5. The low-pressure sealing performance is good, and the sealing surface material is generally made of rubber and plastic, so the sealing performance is good. Limited by the material of the sealing ring, the operating pressure and operating temperature range of the butterfly valve is small. However, the operating pressure and operating temperature range of hard-sealed butterfly valves have been greatly improved.

  1. When the butterfly valve is fully open, it has a small flow resistance. When it is opened between about 15° and 70°, it can perform sensitive flow control. Therefore, butterfly valves are very commonly used in the field of large-diameter adjustment. Since the movement of the butterfly plate of the butterfly valve is wiping, most butterfly valves can be used in media with suspended solid particles. Depending on the strength of the seal, it can also be used for powdery and granular media.

  2. Butterfly valves are suitable for flow regulation. Since the pressure loss of butterfly valves in the pipe is relatively large, about three times that of gate valves, when selecting butterfly valves, the impact of pressure loss on the pipeline system should be fully considered, and the strength of the butterfly plate to withstand the pressure of the pipeline medium when closed should also be considered. . In addition, the operating temperature limitations of the elastomeric seat material at elevated temperatures must also be considered.

  3. .The butterfly valve has a small structural length and overall height, fast opening and closing speed, and good fluid control characteristics. The structural principle of butterfly valve is most suitable for making large diameter valves. When a butterfly valve is required to control flow, the most important thing is to correctly select the specification and type of the butterfly valve so that it can work properly and effectively.