Characteristics of New High Life Stainless Steel Metal Butterfly Valves
At present, butterfly valves, as a component used to achieve on-off and flow control in pipeline systems, have been widely used in many fields such as petroleum, chemical industry, metallurgy, and hydropower. In the well-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 industries such as high temperature resistance, high pressure resistance, corrosion resistance, and wear resistance.
A relatively advanced butterfly valve is a triple eccentric metal hard seal butterfly valve, with the valve body and valve seat as interconnected components. The sealing surface of the valve seat is welded with heat-resistant and corrosion-resistant alloy materials. The multi-layer soft stacked sealing ring is fixed on the valve plate. Compared with traditional butterfly valves, this type of butterfly valve has the advantages of high temperature resistance, easy operation, no friction when opening and closing, and compensates for sealing with the increase of torque of the transmission mechanism when closing, improving the sealing performance of the butterfly valve and extending its service life.
However, this type of butterfly valve still has the following problems during use:
1、 Due to the multi-layer soft and hard laminated sealing ring fixed on the valve plate, when the valve plate is normally open, the medium forms a positive erosion on its sealing surface, and the soft sealing belt in the metal interlayer is directly affected by the erosion, which directly affects the sealing performance.
2、 Due to structural limitations, this structure is not suitable for valves with a diameter below DN200, as the overall structure of the valve plate is too thick and the flow resistance is large.
3、 Due to the principle of a three eccentric structure, the sealing between the sealing surface of the valve plate and the valve seat relies on the torque of the transmission device to press the valve plate towards the valve seat. When in a positive flow state, the higher the medium pressure, the tighter the sealing compression. When the medium in the flow channel is in reverse flow, as the pressure of the medium 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.
A high-performance three eccentric bidirectional hard sealing butterfly valve is characterized in that the valve seat sealing ring is composed of multiple layers of stainless steel sheets on both sides of a soft T-shaped sealing ring. The sealing surface between the valve plate and the valve seat is of an inclined conical structure, and temperature and corrosion resistant alloy materials are deposited on the inclined conical surface of the valve plate; The structure where the spring fixed between the adjusting ring pressure plate and the adjusting bolt on the pressure plate are assembled together. This structure effectively compensates for the tolerance zone between the shaft sleeve and the valve body, as well as the elastic deformation of the valve stem under medium pressure, solving the sealing problem of the valve during the bidirectional exchange medium transportation process. The sealing ring is composed of multiple layers of stainless steel sheets on both sides of a soft T-shape, which has the dual advantages of metal hard sealing and soft sealing. It has zero leakage sealing performance regardless of low or high temperature conditions.
The experiment proves that when the pool is in a positive flow state (the direction of medium flow is the same as the direction of butterfly plate rotation), the pressure on the sealing surface is generated by the torque of the transmission device and the effect of medium pressure on the valve plate. When the positive medium pressure increases, the tighter the compression between the inclined conical surface of the valve plate and the sealing surface of the valve seat, the better the sealing effect. When in a countercurrent state, the sealing between the valve plate and the valve seat is pressed against the valve seat by the torque of the driving device. As the reverse medium pressure increases, when the unit positive pressure between the valve plate and valve seat is less than the medium pressure, the deformation energy stored by the adjusting ring spring after being loaded compensates for the tight pressure on the sealing surface between the valve plate and valve seat, playing an automatic compensation role. Therefore, unlike existing technologies, this utility model does not install soft and hard multi-layer sealing rings on the valve plate, but is directly installed on the valve body
A relatively advanced butterfly valve is a triple eccentric metal hard seal butterfly valve, with the valve body and valve seat as interconnected components. The sealing surface of the valve seat is welded with heat-resistant and corrosion-resistant alloy materials. The multi-layer soft stacked sealing ring is fixed on the valve plate. Compared with traditional butterfly valves, this type of butterfly valve has the advantages of high temperature resistance, easy operation, no friction when opening and closing, and compensates for sealing with the increase of torque of the transmission mechanism when closing, improving the sealing performance of the butterfly valve and extending its service life.
However, this type of butterfly valve still has the following problems during use:
1、 Due to the multi-layer soft and hard laminated sealing ring fixed on the valve plate, when the valve plate is normally open, the medium forms a positive erosion on its sealing surface, and the soft sealing belt in the metal interlayer is directly affected by the erosion, which directly affects the sealing performance.
2、 Due to structural limitations, this structure is not suitable for valves with a diameter below DN200, as the overall structure of the valve plate is too thick and the flow resistance is large.
3、 Due to the principle of a three eccentric structure, the sealing between the sealing surface of the valve plate and the valve seat relies on the torque of the transmission device to press the valve plate towards the valve seat. When in a positive flow state, the higher the medium pressure, the tighter the sealing compression. When the medium in the flow channel is in reverse flow, as the pressure of the medium 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.
A high-performance three eccentric bidirectional hard sealing butterfly valve is characterized in that the valve seat sealing ring is composed of multiple layers of stainless steel sheets on both sides of a soft T-shaped sealing ring. The sealing surface between the valve plate and the valve seat is of an inclined conical structure, and temperature and corrosion resistant alloy materials are deposited on the inclined conical surface of the valve plate; The structure where the spring fixed between the adjusting ring pressure plate and the adjusting bolt on the pressure plate are assembled together. This structure effectively compensates for the tolerance zone between the shaft sleeve and the valve body, as well as the elastic deformation of the valve stem under medium pressure, solving the sealing problem of the valve during the bidirectional exchange medium transportation process. The sealing ring is composed of multiple layers of stainless steel sheets on both sides of a soft T-shape, which has the dual advantages of metal hard sealing and soft sealing. It has zero leakage sealing performance regardless of low or high temperature conditions.
The experiment proves that when the pool is in a positive flow state (the direction of medium flow is the same as the direction of butterfly plate rotation), the pressure on the sealing surface is generated by the torque of the transmission device and the effect of medium pressure on the valve plate. When the positive medium pressure increases, the tighter the compression between the inclined conical surface of the valve plate and the sealing surface of the valve seat, the better the sealing effect. When in a countercurrent state, the sealing between the valve plate and the valve seat is pressed against the valve seat by the torque of the driving device. As the reverse medium pressure increases, when the unit positive pressure between the valve plate and valve seat is less than the medium pressure, the deformation energy stored by the adjusting ring spring after being loaded compensates for the tight pressure on the sealing surface between the valve plate and valve seat, playing an automatic compensation role. Therefore, unlike existing technologies, this utility model does not install soft and hard multi-layer sealing rings on the valve plate, but is directly installed on the valve body
