The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. The butterfly valve has a simple structure, small size and light weight. It consists of only a few parts. And it can be opened and closed quickly by rotating 90°, and the operation is simple. At the same time, the valve has outstanding fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop that occurs through the valve is small, so it has better flow control characteristics.
If the butterfly valve is required to be used as a flow control, the first thing is to accurately select the size and type of the valve. The construction principle of the butterfly valve is particularly suitable for manufacturing large diameter valves. Commonly used butterfly valves include wafer butterfly valves and flange butterfly valves. Wafer type butterfly valve uses double-head bolts to connect the valve between two pipe flanges. Flange type butterfly valve has flanges on the valve, and bolts are used to connect the two flanges of the valve to the pipe flange.
As a component used to complete the on-off and flow control of the pipeline system, the butterfly valve has been extremely widely used in many fields such as petroleum, chemical industry, metallurgy, and hydropower. In the well-known butterfly valve technology, the sealing method is mostly the sealing structure, and the sealing material is rubber, polytetrafluoroethylene, etc. Due to the constraints of structural features, it is not suitable for industries such as high temperature, high pressure, corrosion resistance and wear resistance.
An existing relatively advanced butterfly valve is a three-partition metal hard-sealed butterfly valve. The valve body and the valve seat are connected components. The outer surface of the valve seat seal is welded with temperature-resistant and corrosion-resistant alloy materials. The multi-layer soft laminated sealing ring is fixed on the valve plate. Compared with the traditional butterfly valve, this butterfly valve has high temperature resistance, simple operation, no conflict in opening and closing. When closing, the torque of the transmission organization increases to compensate for the sealing, which improves the performance of the butterfly valve. The advantages of sealing function and extended service life.
However, this butterfly valve still has the following questions in the application process:
1. Because the multi-layer soft and hard stacked sealing ring is fixed on the valve plate, when the valve plate is normally open, the medium will form a positive wash on its sealing surface. The soft sealing band in the metal sheet sandwich will directly affect the sealing function after being washed.
2. Constrained by 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 three-partial pain structure, the sealing between the sealing surface of the valve plate and the valve seat is to press the valve plate against the valve seat by the torque of the transmission equipment. In positive flow conditions, the higher the medium pressure, the tighter the seal and kneading. When the flow channel medium flows back, the unit positive pressure between the valve plate and the valve seat is lower than the medium pressure as the medium pressure increases, the seal opening leaks.
The high-function triple migraine two-way 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 of the valve plate and the valve seat is of an oblique cone structure, and temperature and corrosion resistant alloy materials are surfacing welded on the surface of the oblique cone of the valve plate; the tension spring fixed between the adjusting ring pressure plate and the pressure plate adjusting bolt equipment are constructed together.
This structure effectively compensates for the elastic deformation of the service belt between the shaft sleeve and the valve body and the valve stem under the pressure of the medium, and solves the sealing problems of the valve in the two-way exchange of the medium conveying process. The sealing ring is made of soft T-shaped multi-layer stainless steel sheets on both sides, which has the advantages of two layers of metal hard seal and soft seal. It has the sealing function of zero leakage regardless of low temperature and high temperature.
Experiments have confirmed that when the pool is positive (the direction of movement of the medium is the same as the rolling direction of the butterfly plate), the pressure on the sealing surface is caused by the torque of the transmission equipment and the action of the medium pressure on the valve plate. When the positive medium pressure increases, the tighter the oblique cone surface of the valve plate and the sealing surface of the valve seat are kneaded, the better the sealing effect. In the case of reverse flow, the seal between the valve plate and the valve seat is pressed against the valve seat by the torque of the driving device. With the increase of the reverse medium pressure, when the unit positive pressure between the valve plate and the valve seat is less than the medium pressure, the stored deformation of the tension spring of the conditioning ring after being loaded can offset the tight pressure of the valve plate and the sealing surface of the valve seat Play the role of active compensation. Therefore, the utility model is not equipped with a soft and hard multi-layer sealing ring on the valve plate like the existing technology, but is directly installed on the valve body. Adding a conditioning ring in the center of the pressure plate and the valve seat is a very ambitious two-way hard sealing method. . It will replace gate valves, globe valves and ball valves.
