The butterfly valve opening and closing part is a butterfly plate, which is driven by the valve stem and rotates 90° around its own axis in the valve body to achieve the purpose of opening and closing or adjustment. It has simple structure, small size, short structure length, small size, light weight, which is suitable for large-diameter large butterfly valves.
The butterfly valves are usually less than 90° from fully open to fully closed. The butterfly valves and the butterfly stems have no self-locking ability. For the positioning of the butterfly plate, a worm gear reducer must be installed on the valve stem. The use of worm gear reducer can not only give the butterfly plate self-locking ability, making the butterfly plate stop at any position, but also improve the operation performance of the valve. The characteristics of the industrial butterfly valves: high temperature resistance, high applicable pressure range, large nominal diameter of the valve, the valve body is made of carbon steel, and the sealing ring of the valve plate uses a metal ring instead of a rubber ring. The large high temperature butterfly valves are made of steel plate welding, and are mainly used for flue ducts and gas pipes of high temperature media.
1. The butterfly valves have the characteristics of simple structure, small size, light weight, low material consumption, small installation size, rapid switching, 90° reciprocating rotation, and small driving torque. They are used to cut off, connect, and adjust the medium in the pipeline. They have good fluid control characteristics and close sealing performance.
2. The butterfly valves can transport mud, and the accumulation of liquid at the pipe mouth is the least. Under low pressure, good sealing can be achieved with good adjustment performance.
3. The streamlined design of the butterfly plate makes the fluid resistance loss small, which can be described as an energy-saving product.
4. The valve stem is a through-rod structure, after quenching and tempering and it has good comprehensive mechanical properties, corrosion resistance and scratch resistance. When the butterfly valves are opened and closed, the valve stems only rotate and do not move up and down. The packing of the valve stem is not easy to be damaged and the sealing is reliable. It is fixed with the butterfly plate cone pin, and the extended end is designed to prevent the valve stem from collapsing when the connection between the valve stem and the butterfly plate is accidentally broken.
5. Connection methods include flange connection, butt connection, butt welding connection and lug butt clamp connection.