Characteristics of a New Type of High Life Stainless Steel Butterfly Valve and Problems in the Use of the Butterfly Valve
At present, expansion butterfly valve, as a component used to realize on-off and flow control of pipeline system, has been used in petroleum, chemical industry, metallurgy, hydropower and many other fields.
Flexible butterfly valve
Retractable butterfly valve (12 sheets)
It has been widely used in the field. In the well-known butterfly valve technology, its sealing form mostly uses the sealing structure, the sealing material is rubber, PTFE and so on. Due to the limitation of structural characteristics, it is not suitable for high temperature, high pressure, corrosion and wear resistance industries. A more advanced butterfly valve is a three-eccentric metal hard-sealed butterfly valve. The valve body and seat are connected components. The sealing surface layer of the valve seat is surfaced with heat-resistant and corrosion-resistant alloy materials. The multi-layer soft overlapping seal ring is fixed on the valve plate. Compared with the traditional butterfly valve, the butterfly valve has the advantages of high temperature resistance, easy operation, no friction in opening and closing. When closing, it compensates for the seal with the increase of the torque of the transmission mechanism, and improves the sealing performance and prolongs the service life of the butterfly valve.
Working principle editor
Expansion butterfly valve is a kind of valve which uses circular butterfly plate as opening and closing parts and rotates with the stem to open, close and adjust the fluid passage. The butterfly plate of the telescopic butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the telescopic butterfly valve body, the disc butterfly plate rotates around the axis, and the rotation angle is between 0 ~90. When the rotation angle is between 0 ~90, the valve is fully open.
Structural features editor
The telescopic butterfly valve has the characteristics of simple structure, small volume, light weight, low material consumption, small installation size, fast switching, 90 degree reciprocating rotation and small driving moment. It is used to cut off, connect and regulate the medium in the pipeline, and has good fluid control characteristics and sealing performance. When the expansion butterfly valve is in full open position, the thickness of the expansion butterfly valve is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has better flow control characteristics. The expansion butterfly valve has elastic seal and metal seal. Elastic sealing valve, sealing ring can be inlaid on the body or attached to the butterfly plate.
Metal-sealed telescopic butterfly valves generally have longer service life than elastic-sealed valves, but it is difficult to achieve complete sealing. Metal seals can adapt to higher working temperature, while elastic seals have temperature limitations. If the expansion butterfly valve is required to be used as flow control, the main thing is to correctly select the size and type of the valve. The structure principle of telescopic butterfly valve is especially suitable for making large caliber valves. Telescopic butterfly valves are not only widely used in petroleum, gas, chemical industry, water treatment and other general industries, but also used in the cooling water system of thermal power plants.
The commonly used telescopic butterfly valves are butterfly valves, flanged butterfly valves and butt welding butterfly valves. The butterfly valve is connected between two pipe flanges by double-head bolts; the flanged butterfly valve is connected with flanges on the valve, and the flanges on both ends of the valve are connected with pipe flanges by bolts; the two ends of butterfly valve are welded with pipelines. The streamlined design of butterfly plate can reduce the loss of fluid resistance, so it is an energy-saving product. The valve stem is a through-rod structure. After quenching and tempering treatment, it has good comprehensive mechanical properties, corrosion resistance and scratch resistance. When the butterfly valve is opened and closed, the stem is only rotated but not lifted. The filler of the stem is not easy to destroy and the seal is reliable. Fixed with the butterfly plate cone pin, the extension end is anti-washout design, so as to avoid the valve stem bursting when the connection between the stem and the butterfly plate accidentally breaks.
1. It is compact and light, easy to disassemble, assemble and repair, and can be installed at any position.
2. The structure is simple and compact, the operation torque is small, and the 90-degree rotation opens quickly.
3. Flow characteristic tends to straight line and has good regulation performance.
4. The connection between butterfly plate and valve stem adopts pinless structure, which overcomes the possible internal leakage point.
5. Seals can be replaced, and the seals are reliable to achieve bidirectional seals.
6. The butterfly plate can be sprayed with coating according to user's requirements, such as nylon or PTFE.
7. The valve can be designed as flange connection and clamp connection.
8. The driving mode can be manual, electric or pneumatic.