Butterfly Valve Cast Iron Body Suppliers
Butterfly valve (English: butterfly valve) refers to a closing member (valve or disc) is a disc, a valve that rotates around the valve shaft to open and close, mainly used for cutting and throttling on the pipeline.
The butterfly valve opening and closing member is a disc-shaped butterfly plate that rotates around its own axis in the valve body to achieve the purpose of opening and closing or adjusting.
The butterfly valve is normally less than 90° from full opening to full closing. The butterfly valve and the butterfly rod have no self-locking ability. For the positioning of the butterfly plate, a worm gear reducer is added to the valve stem. The use of a worm gear reducer not only enables the disc to have a self-locking capability, but also stops the disc at any position and improves the valve's operating performance.we are cast iron body suppliers,we can guarantee quality.
The characteristics of the industrial special butterfly valve can withstand high temperature, the applicable pressure range is also high, the valve has a large nominal diameter, the valve body is made of carbon steel, and the sealing ring of the valve plate uses a metal ring instead of the rubber ring.
Large high temperature butterfly valves are manufactured by steel plate welding and are mainly used for flue ducts and gas pipes of high temperature media.
In the 1930s, the United States invented the butterfly valve, which was introduced to Japan in the 1950s and was widely adopted in Japan in the 1960s. In China, it was promoted after the 1970s.
At present, butterfly valves in the world generally have been replaced by DN300 mm butterfly valves. Compared with the gate valve, the butterfly valve has a short opening and closing time, a small operating torque, a small installation space and a 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 disadvantage of the rubber sealing butterfly valve is that when used for throttling, cavitation may occur due to improper use, and the rubber seat may be peeled off and damaged.
To this end, the metal sealing butterfly valve has been developed internationally, and the cavitation zone has been reduced. In recent years, China has also developed a metal sealing butterfly valve. In recent years, a cam-shaped butterfly valve resistant to cavitation, low vibration and low noise has been developed in Japan.
Generally, the life of the sealing seat is under normal conditions, rubber is 15-20 years, and metal is 80-90 years. However, how to choose correctly should be based on industrial and mining requirements.
The relationship between the opening and flow of a cast iron butterfly valve varies substantially linearly. If it is used to control the flow, its flow characteristics are closely related to the flow resistance of the piping. For example, the diameters and forms of the two pipe installation valves are all the same, and the pipe loss coefficient is different, and the flow difference of the valve is also large.
If the valve is in a state of large throttle, the back of the valve plate is prone to cavitation and may damage the valve. Generally, it is used outside of 15°.
When the cast iron butterfly valve is at the middle opening degree, the shape of the opening formed by the valve body and the front end of the disc is centered on the valve shaft, and the two sides are formed to complete different states. The front end of the butterfly plate moves in the direction of the water and the opposite side flows in the opposite direction. Therefore, the one side valve body and the valve plate form a nozzle-like opening, and the other side is similar to the orifice-shaped opening, the nozzle side has a much faster flow rate than the throttle side, and the negative pressure is generated under the throttle side valve. Rubber seals tend to fall off.we are cast iron body suppliers,we can guarantee quality.
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