Cast iron eccentric bidirectional sealing butterfly valve

Abstract

The invention provides a cast iron eccentric bidirectional sealing butterfly valve which is characterized in that a sealing pair consists of an independent floating valve seat and an O-shaped ring on the floating valve seat; and the side face and bottom of the valve seat are provided with O-shaped seal rings made of a plastic or rubber material. The invention has the advantages that the cast iron eccentric bidirectional sealing butterfly valve can bear the pressure (within 1.25 times of nominal pressure) applied from any side by media, and the purpose of preventing the backflow of media can be achieved by only installing one cast iron eccentric bidirectional pressure butterfly valve but not adding a check valve or other bidirectional pressure valves additionally; and at the same time, because the welding property of the floating valve seat is excellent, different materials can be welded according to different media, thus the butterfly valve provided by the invention is better in abrasion resistance and corrosion resistance, and the service life of the valve can be prolonged.

Description

technical field [0001] The invention relates to a butterfly valve structure, in particular to a cast iron eccentric bidirectional sealing butterfly valve which can be blocked from any end of the medium entering the valve and meets the requirement of zero leakage. Background technique [0002] In the traditional manufacturing of cast iron eccentric butterfly valve, due to the manufacturing process and structure, the medium can only be completely sealed when it enters the medium in the closing direction of the butterfly plate of the butterfly valve. When the medium enters in the opposite direction, as the pressure of the medium increases, due to the Due to the eccentric structure, the butterfly plate and the stem of the butterfly valve will be subjected to a thrust in the direction of opening the valve, which is opposite to the direction of the driving force used to close the valve, that is to say, the preload specific pressure of the valve will be reduced. , when the pre-tigh...

AI Technical Summary

Problems solved by technology

[0002] In the traditional manufacturing of cast iron eccentric butterfly valves, due to the manufacturing process and structure, the medium can only be completely sealed when it enters the closing direction of the butterfly plate of the butterfly valve. When entering the medium in the opposite direction, as the pressure of the medium increases, the butterfly valve Due to the eccentric structure, the butterfly plate and the stem of the butterfly valve will be subjected to a thrust in the direction of opening the valve, which is opposite to the direction of the driving force used to close the valve, that is to say, the preload pressure of the valve will be reduced. , when the pre-tightening specific pressure is reduced to the minimum sealing specific pressure, the butterfly valve will leak; at the same time, due to the poor welding performance of cast iron, the material that can be surfacing on the cast iron valve body is limited, and the material of surfacing welding is often limited. The hardness is very low or not resistant to corrosion, which limits the applicable environment of this type of butterfly valve and greatly reduces the service life

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