Fluorine lined DC globe valve: The sealing of disc valves is classified according to their structural form

The sealing structure forms of the series of disc valves produced include single eccentric seal, double eccentric seal, triple eccentric seal, and variable eccentric seal. The sealing principles of various structural types of disc valves are briefly described as follows:
1. Sealing principle of single eccentric sealing disc valve
2. Sealing principle of double eccentric sealing butterfly valve
Due to the size b offset between the center of rotation of the butterfly plate (i.e. the valve shaft center) and the centerline of the valve body on the basis of a single eccentric butterfly valve, the sealing surface of the butterfly plate will detach from the valve seat sealing surface faster than that of a single eccentric sealing butterfly valve during the opening process. When the butterfly plate rotates to 8 ° -12 °, PTFE lined valve The sealing surface of the butterfly valve is detached from the valve seat seal. When opened, a larger gap y is formed between the two sealing surfaces. The design of this type of butterfly valve greatly reduces mechanical wear and compression deformation between the two sealing surfaces, thereby improving the sealing performance of the butterfly valve.
3. Sealing principle of three eccentric sealing butterfly valve
Due to the formation of a β - angle offset between the center line of the valve seat and the center line of the valve body on the basis of the double eccentric butterfly valve, the butterfly valve is clamped during the valve opening process Fluorine-lined Butterfly Valve The sealing surface of the butterfly plate immediately disengages from the valve seat sealing surface at the moment of opening, and only contacts and compresses the valve seat sealing surface at the moment of closing. When opened, a gap y is formed between the two sealing surfaces, which is the same as the double eccentric sealing butterfly valve. The design of this type of butterfly valve eliminates mechanical wear and scratches between the two sealing surfaces, greatly improving the sealing performance and service life of the butterfly valve.
4. Sealing principle of eccentric sealing butterfly valve
The point of the variable eccentricity butterfly valve is that the valve stem shaft for installing the butterfly plate is a three section shaft structure. The two sections of the three section shaft stem are concentric, and the centerline of the central section shaft is offset from the two end axes by a center distance. The butterfly plate is installed on the intermediate shaft section. This eccentric structure makes the butterfly plate double eccentric when in the fully open position, and single eccentric when the butterfly plate rotates to the closed position. Due to the action of the eccentric shaft, when approaching closure, the butterfly plate moves a distance into the sealing cone of the valve seat, and the sealing surface of the butterfly plate and the valve seat matches to achieve reliable sealing performance.
Due to the eccentric setting of the center of rotation of the butterfly valve (i.e. the center of the valve shaft) and the sealing section of the butterfly valve, Fluorine lined valve factory The sealing surface of the butterfly plate gradually separates from the sealing surface of the valve seat. When the butterfly plate rotates to 20 °~25 °, the sealing surface of the butterfly plate separates from the sealing surface of the valve seat. When opened, a gap x is formed between the two sealing surfaces, which greatly reduces the relative mechanical wear and compression between the two sealing surfaces during the opening and closing process of the butterfly valve, thereby ensuring the sealing of the butterfly valve.

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