In the 1930s, the United States invented the butterfly valve. It was introduced to Japan in the 1950s and was widely used in Japan in the 1960s. In China, it was after the 1970s. Low operating torque, small installation space and light weight. Taking DN1000 as an example, the butterfly valve is about 2T, and the gate valve is about 3.5T, and the butterfly valve is easy to combine with various driving devices, and has good durability and reliability.
The butterfly valve can be divided into a bias plate type, a vertical plate type, a slant plate type and a lever type according to the structure. According to the sealing form, it can be divided into two types: soft seal type and hard seal type. The soft seal type is generally sealed with a rubber ring, and the hard seal type is usually sealed with a metal ring. According to the connection type, it can be divided into flange connection and clip type connection; according to the transmission mode, it can be divided into manual, gear transmission, pneumatic, hydraulic and electric.
Butterfly valve installation method:
1. Before installation, please confirm whether the product performance and media flow arrow match the movement conditions, and insert the valve cavity clean, do not allow foreign matter with impurities on the seal ring and the butterfly plate, and never allow it to be closed before cleaning. Disc to avoid damage to the seal.
2, the disc mounting flange is recommended to use the special flange of the disc valve, that is, HGJ54-91 socket welding steel flange.
3, installed in the location of the pipeline, zui good position for the vertical, but not flip.
4, need to adjust the flow during use, there is a worm gear box for control.
5, open and close the number of disc valves, in about two months, open the worm gear cover, check whether the butter is normal, should maintain the right amount of butter.
6. Check the compression requirements of each joint, that is, ensure the beeiness of the packing, and ensure that the valve stem rotates flexibly.
7. The metal sealing butterfly valve product is not suitable for installation at the end of the pipeline. If it must be installed at the end of the pipeline, it is necessary to adopt the fitting outlet flange to prevent the sealing ring from being over-compressed.
8. The valve stem is installed and used to check the valve usage regularly, and the fault is found to be eliminated in time.
9, the possible failures in time to eliminate the method as detailed in the following table: butterfly valve common faults and solutions
Possible failures:
Cause sealing surface leak
1. The disc and sealing surface are covered with debris.
2, the butterfly plate, sealing surface closed position is not consistent
3. The flanges on the outlet side are not uniformly loaded or are not required according to Figure 1.
4. The pressure test direction is not as required in Figure 1.
Elimination method:
1. Eliminate impurities and clean the valve cavity
2. Adjust the adjusting screw of the worm gear or electric actuator to achieve the correct valve closing position.
3, check the fitting flange plane and bolt compression country, should be evenly pressed
4. Pressing in the direction of the tip seal
Method for eliminating leakage at both ends of the valve:
1. The seal gaskets on both sides are invalid.
2, the pipe flange tension is uneven or not pressed
3, the sealing ring upper and lower sealing gaskets are invalid
Elimination method
1, replace the gasket
2, press the flange bolt (even force)
3. Remove the pressure ring of the valve, replace the sealing ring, and replace the gasket.
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