Brief Analysis of the Structure Characteristics and Working Principle of Vacuum Butterfly Valve

Vacuum butterfly valve features:

1. It is designed and manufactured by adopting the new structure of medium-line disc and short-structure steel plate welding. It is compact in structure, light in weight, easy to install, small in flow resistance and large in circulation. It avoids the influence of high temperature expansion and is light in operation.

2, no connecting rods, bolts, etc., reliable operation and long service life. Can be installed in multiple stations, independent of the flow of media.

use:

This butterfly valve is a non-hermetic valve, widely used in the production process the temperature of both media materials, metallurgical, mining, and electric power ≤300 ℃ nominal pressure of 0.1Mpa pipe for communication with the opening and closing or regulating medium quantity.

Structural features:

The butterfly valve is designed and manufactured by adopting a new structure of medium-line disc and short-structure steel plate welding. The structure is compact, light in weight, easy to install, small in flow resistance, large in circulation, avoiding the influence of high temperature expansion, and light in operation. No connecting rods, bolts, etc. in the body, reliable operation and long service life. Can be installed in multiple stations, independent of the flow of media.

working principle:

The butterfly valve is driven by an electric motor to drive the actuator, so that the disc is freely rotated within a range of 90° to achieve the purpose of opening and closing or regulating the flow of the medium. At present, the fluorine-lined butterfly valve and the rubber-lined butterfly valve have been widely used in many fields such as petroleum , chemical, metallurgy, and hydropower, as a component for implementing the on-off and flow control of the pipeline system. In the well-known butterfly valve technology, the sealing form is mostly sealed, and the sealing material is rubber, polytetrafluoroethylene or the like. Due to structural limitations, it is not suitable for industries such as high temperature resistance, high pressure, corrosion resistance and wear resistance. A relatively advanced butterfly valve is a three-eccentric metal hard sealing butterfly valve. The valve body and the valve seat are connected members, and the sealing surface layer of the valve seat is welded with a temperature-resistant and corrosion-resistant alloy material. The multi-layer soft stack sealing ring is fixed on the valve plate. Compared with the traditional butterfly valve, the butterfly valve has high temperature resistance, is light in operation, and has no friction in opening and closing. When closing, the seal is compensated with the increase of the torque of the transmission mechanism, and the butterfly valve is improved. The sealing performance and the advantage of extending the service life.

A, the vacuum butterfly valve still has the following problems during use:

1. Since the multi-layer soft and hard stack sealing ring is fixed on the valve plate, when the valve plate is normally open, the medium forms a front surface flushing on the sealing surface thereof, and the soft sealing band in the metal sheet interlayer is directly washed to affect the sealing performance.

2. Limited by structural conditions The structure is not suitable for valves with a diameter below DN200. The reason is that 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 sealing surface of the valve plate and the valve seat is pressed against the valve seat by the torque of the transmission device. In the positive flow state, the higher the medium pressure, the tighter the seal extrusion. When the flow medium is reversed, the unit positive pressure between the valve plate and the valve seat is less than the medium pressure as the medium pressure increases, and the seal begins to leak.

4. The high performance ventilation butterfly valve is characterized in that: the valve seat sealing ring is composed of a plurality of 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 conical structure, and the temperature-resistant and corrosion-resistant alloy material is deposited on the inclined conical surface of the valve plate; the spring fixed between the adjusting ring pressure plate and the adjusting bolt assembly on the pressure plate are assembled. The structure effectively compensates for the tolerance band between the 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 two-way interchangeable medium conveying process.

The soft T-shaped multi-layer stainless steel sheet is used to form the sealing ring, which has the double advantages of metal hard seal and soft seal, and has zero leakage sealing performance at low temperature and high temperature. When the test proves that the positive flow state of the tank (the direction of flow of the medium is the same as the direction of rotation of the disc), the pressure of the sealing surface is caused by the action of the torque of the transmission and the pressure of the medium on the valve plate. When the positive medium pressure increases, the tighter surface of the valve plate and the sealing surface of the valve seat are pressed tighter, and the sealing effect is better.

In the countercurrent state, the seal between the valve plate and the valve seat is biased against the drive to press the valve plate against the valve seat. As the pressure of the reverse medium increases, the unit positive pressure between the valve plate and the valve seat is less than the medium pressure, and the deformation of the spring of the adjusting ring after being loaded can compensate the tight pressure of the sealing surface of the valve plate and the valve seat. Plays an automatic compensation role.

Therefore, the utility model does not install a soft and hard multi-layer sealing ring on the valve plate as in the prior art, but is directly mounted on the valve body, and an adjustment ring is added between the pressure plate and the valve seat, which is an ideal two-way hard sealing method. . It will replace the gate valve and the ball valve.

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