Working principle of stainless steel electric butterfly valve

The stainless steel electric butterfly valve mechanism enables the butterfly plate to rotate freely within a range of 90° to achieve the purpose of opening, closing or adjusting the flow of the medium. At present, fluorine-lined butterfly valves and rubber-lined butterfly valves have been widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower, etc. as components to realize the on-off and flow control of pipeline systems. In the known butterfly valve technology, the sealing form mostly adopts a sealing structure, and the sealing materials are rubber, polytetrafluoroethylene, etc. Due to the limitations of structural characteristics, it is not suitable for high temperature resistance, high pressure resistance, corrosion resistance, wear resistance and other industries. The existing comparative butterfly valve is a three-eccentric metal hard seal butterfly valve, the valve body and the valve seat are an integrated component, the valve seat sealing surface layer is welded with heat-resistant and corrosion-resistant alloy materials, and a multi-layer soft stack sealing ring is fixed on the valve plate. Compared with the traditional butterfly valve, this kind of butterfly valve is resistant to high temperature, easy to operate, and has no friction when opening and closing. When closing, the torque of the transmission mechanism increases to compensate for the seal, which improves the sealing performance of the butterfly valve and extends its service life.

The following problems still exist in the use of stainless steel electric butterfly valves:

1. Since there are multiple layers of soft and hard sealing rings fixed on the valve plate, when the valve plate is in the normally open state, the medium will cause positive erosion on its sealing surface. After the soft sealing belt in the metal sheet interlayer is washed away, it will directly affect the sealing performance.

2. Due to structural conditions, this structure is not suitable for valves with a 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 the rubber lined butterfly valve, the seal between the valve plate sealing surface and the valve seat is pressed against the valve seat by the torque of the transmission device. In the downstream state, the higher the medium pressure, the tighter the seal is squeezed. When the medium in the flow channel flows backward, as the medium pressure increases, the unit positive pressure between the valve plate and the valve seat is less than the medium pressure, and the seal begins to leak.

4. High-performance gas butterfly valve, characterized by: the valve seat sealing ring is composed of multiple layers of stainless steel sheets on both sides of the soft T-shaped sealing ring. The sealing surface of the valve plate and the valve seat is an oblique cone structure, and the oblique cone surface of the valve plate is welded with heat-resistant and corrosion-resistant alloy materials; the spring fixed between the adjusting ring and the pressure plate is assembled with the adjusting bolt on the pressure plate. This structure effectively compensates for the tolerance band between the sleeve and the valve body and the elastic deformation of the valve stem under the pressure of the medium, and solves the sealing problem of the valve when the medium is transported in both directions.

5. The sealing ring is composed of T-shaped multi-layer stainless steel sheets with soft surfaces on both sides, which has the dual advantages of metal hard sealing and soft sealing, and has zero leakage sealing performance regardless of low or high temperature conditions. Experiments have shown that when the pool is in a positive flow state (the flow direction of the medium is the same as the rotation direction of the butterfly plate), the pressure on the sealing surface is generated by the torque of the transmission device and the medium pressure acting on the valve plate. When the positive medium pressure increases, the tighter the squeeze between the oblique cone surface of the valve plate and the sealing surface of the valve seat, the better the sealing effect. When in a reverse flow state, the seal between the valve plate and the valve seat relies on the torque of the drive device to force the valve plate to press against the valve seat. As the reverse medium pressure increases, when the unit positive pressure between the valve plate and the valve seat is less than the medium pressure, the deformation stored by the adjustment ring spring after being loaded can compensate for the tight pressure between the valve plate and the valve seat sealing surface, and play an automatic compensation role. Therefore, the utility model does not install a soft and hard multi-layer sealing ring on the valve plate like the prior art, but is directly installed on the valve body, and an adjustment ring is installed between the pressure plate and the valve seat, which is an ideal two-way hard sealing method. It can replace gate valves and ball valves