Lined Butterfly Valve

Abstract

To provide a butterfly valve, which is a liner type butterfly valve with corrosion resistance to fluids, which can simultaneously improve air-to-earth sealing and shaft sealing to reliably prevent leakage. They maintain their tightness even when moving. A valve disc (12) covered by a liner (32) is provided in a cylindrical valve body (11) covered by a seat liner (20) to open and close via a valve stem (13). Clamp the shaft sealing part (18) of the valve stem (13) between the ring body (22) and the valve stem (13), thereby preventing the diameter expansion of the shaft sealing part (18), and using the The rebound force of the spring (44) in the shaft mounting part (27) of (11) pushes the valve seat lining (20) on the boss surface (37) of the valve disc (12) through the ring body (22), This maintains the airtightness of the sky-earth seal ( 19 ).

Description

technical field [0001] The present invention relates to a liner type butterfly valve with a resin lining on the inner peripheral surface of a valve body and a valve box, and in particular to a butterfly valve with improved airtightness near the air and earth side of the valve body and the shaft sealing portion of the valve rod. Background technique [0002] Conventionally, as butterfly valves used in facilities for the chemical industry where highly corrosive fluids flow, or in food-related flow paths, etc., it is known that a metal core of the valve body is A butterfly valve with a so-called liner structure is covered with a resin liner layer and a resin seat ring is mounted on the inner peripheral surface of the valve box. The body lining layer and resin valve seat ring of this lined butterfly valve are made of resin materials such as PTFE or PFA. Other than these materials, they are not in contact with fluids, so they are suitable for severe corrosive fluids, chemical flu...

AI Technical Summary

Problems solved by technology

In this case, the upper and lower sides of the resin lining layer 3 are biased toward the secondary side with respect to the resin valve seat ring 5 , and the adhesiveness is deteriorated. The airtightness of the surrounding valve rod 6 and the valve box 9, that is, the airtightness of the air and earth is reduced, and so-called primary leakage may occur.

[0026] Furthermore, in Figure 9 In the process, as the valve body 4 moves, the valve rod 6 moves to the secondary side, and thus the adhesiveness between the valve rod covering part 7 and the extension covering part 8 also deteriorates, and the valve rod covering part 7 and the extension covering part 8 The sealing performance between the valve rod 6 and the valve box 9, that is, the shaft sealing performance of the valve rod 6 is reduced, and so-called secondary leakage may occur.

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