DIN Type Advanced Butterfly Valve

In the 30 ‘s, the United States invented butterfly valves, which were introduced to Japan in the 50, and were only widely used in Japan in the 60, while the promotion in our country was after the 70. At present, the world is generally more than DN300 mm butterfly valve has gradually replaced the gate valve. Compared with gate valve, butterfly valve has short opening and closing time, small operating torque, small installation space and light weight.

Take DN1000 as an example, butterfly valve about 2T, and gate valve about 3.5T, and butterfly valve easy to combine with a variety of drive devices, has good durability and reliability. Rubber sealed butterfly valve disadvantage is used for throttling, due to improper use will produce cavitation, so that rubber seat peeling, damage and other situations occur.

To this end, now the international development of Metal seal butterfly valve, cavitation area reduction, in recent years, China has also developed metal seal butterfly valve, in recent years in Japan has also developed gas corrosion resistance, low vibration, low noise comb-shaped butterfly valve. General sealing seat life under normal conditions, rubber 15-20, metal 80-90.

However, how to choose correctly should be based on the requirements of the working conditions. The relationship between the opening degree of butterfly valve and the flow rate is basically linear proportional change.

If used to control the flow rate, its flow characteristics and the flow resistance of the piping is also closely related, such as two pipe installation valve caliber, form and so on, and the pipeline loss coefficient is different, the valve flow difference will be very large.

If the valve is in a large state of throttling, the back of the valve plate is prone to cavitation, there is the possibility of damage to the valve, generally used outside the 15°. Butterfly valve in the medium opening, valve body and butterfly plate front end of the formation of the opening shape to the valve shaft as the center, the two sides of the formation of a different state, one side of the butterfly plate front end in the direction of water movement, the other side of the reverse flow of water direction, therefore, one side of the valve body and valve plate formed like a

Nozzle side than throttle side flow rate is much faster, and throttle side valve will produce negative pressure, often appear rubber seals off. Butterfly valve operating torque, due to open and valve opening and closing direction of different values, horizontal butterfly valve, especially large diameter valve, because of the depth of water, valve shaft, sewer head caused by the torque can not be ignored. In addition, when the valve inlet side device elbow, the formation of deflection, the torque will be increased. When the valve is in the middle opening, the operating mechanism needs to be self-locking due to the effect of the current power moment.