vacuum butterfly valve structure characteristics and working principle
vacuum butterfly valve features :
1. It is designed and manufactured by adopting the new structure form of welding the central line type disc plate and short structure steel plate, with compact structure, light weight, easy installation, small flow resistance, large flow capacity, avoiding the influence of high temperature expansion, and easy to operate.
2. There is no connecting rod, bolt, etc. inside, it works reliably and has long service life. It can be installed in multi station, not affected by the flow direction of medium.
vacuum butterfly valve application:
Vacuum butterfly valve is a kind of non airtight butterfly valve, which is widely used in the production process of building materials, metallurgy, mining, electric power, etc. the medium temperature is ≤ 300 ℃ and the nominal pressure is 0.1MPa. It is used to connect, open and close or adjust the medium quality.
vacuum butterfly valve structural features:
The vacuum butterfly valve is designed and manufactured by adopting the new structure form of welding the central line type disc plate and short structure steel plate. It has the advantages of compact structure, light weight, easy installation, small flow resistance, large flow capacity, avoiding the influence of high temperature expansion and easy operation. There is no connecting rod, bolt, etc. in the body, it works reliably and has a long service life. It can be installed in multi station, not affected by the flow direction of medium.
vacuum butterfly valve working principle:
The vacuum butterfly valve is driven by the motor to drive the actuator, so that the disc plate can rotate freely within 90 ° to achieve the purpose of opening and closing or regulating the medium flow. At present, fluorine lined butterfly valve and rubber lined butterfly valve, as a component used to realize the on-off and flow control of pipeline system, have been widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower and so on.
In the well-known butterfly valve technology, its sealing form mostly adopts the sealing structure, and the sealing materials are rubber, polytetrafluoroethylene, etc. Due to the limitation of structural characteristics, it is not suitable for high temperature, high pressure, corrosion resistance, wear resistance and other industries. The valve seat and valve seat are made of three kinds of advanced hardfacing materials. Compared with the traditional butterfly valve, this kind of butterfly valve has the advantages of high temperature resistance, light operation, no friction in opening and closing. When closing, it compensates the sealing with the increase of the torque of the transmission mechanism, which improves the sealing performance and prolongs the service life of the butterfly valve.
A. The following problems still exist in the use of vacuum butterfly valve
1. Due to the multi-layer soft and hard laminated seal ring fixed on the valve plate, when the valve plate is normally open, the medium will form a positive scour on its sealing surface, and the soft sealing band in the metal interlayer will be scoured, which will directly affect the sealing performance.
2. Limited by the structural conditions, the structure is not suitable for the valve with diameter below DN200, because the overall structure of the valve plate is too thick and the flow resistance is large.
3. Due to the principle of rubber lined butterfly valve, the sealing between the sealing surface of the valve plate and the valve seat depends on the torque of the transmission device to press the valve plate to the valve seat. In the positive flow state, the higher the medium pressure, the tighter the seal extrusion. When the medium flow counter current, with the increase of medium pressure, the unit positive pressure between valve plate and valve seat is less than the medium pressure, the seal begins to leak.
4. The high-performance ventilation butterfly valve is characterized in that the valve seat sealing ring is composed of multi-layer stainless steel sheets on both sides of the soft T-shaped sealing ring.
The sealing surface of valve plate and valve seat is inclined conical structure, which is overlaid with heat-resistant and corrosion-resistant alloy materials on the inclined conical surface of valve plate; the structure is composed of spring fixed between the pressure plate of regulating ring and adjusting bolt on the pressure plate. This structure effectively compensates the tolerance zone between the shaft sleeve and the valve body and the elastic deformation of the valve stem under the medium pressure, and solves the sealing problem of the valve in the process of two-way exchange medium transportation.
The sealing ring is composed of soft T-shaped multi-layer stainless steel sheets on both sides, which has the double advantages of metal hard sealing and soft sealing. It has zero leakage sealing performance no matter at low or high temperature. The test shows that the pressure on the sealing surface is caused by the torque of the transmission device and the action of the medium pressure on the valve plate when the pool is in the positive flow state (the flow direction of the medium is the same as that of the butterfly plate). When the positive medium pressure increases, the closer the oblique conical surface of the valve plate and the sealing surface of the valve seat squeeze, the better the sealing effect is.
In countercurrent state, the sealing between valve plate and valve seat depends on the torque of driving device to press the valve plate to the valve seat. When the unit positive pressure between the valve plate and the valve seat is less than the medium pressure with the increase of the reverse medium pressure, the deformation stored in the spring of the regulating ring after loading can compensate the tight pressure on the sealing surface of the valve plate and the valve seat, and play an automatic compensation role.
Therefore, unlike the existing technology, the utility model is directly installed on the valve body instead of installing a soft and hard multi-layer sealing ring on the valve plate, and adding an adjusting ring between the pressing plate and the valve seat is a very ideal two-way hard sealing mode. It will replace gate valve and ball valve.