An all-metal stem sealing mechanism and flat gate valve

Abstract

The invention discloses an all-metal valve rod sealing mechanism which comprises a valve cover, a packing gland located on the valve cover and a valve rod penetrating through the packing gland. A sealing cavity is formed among the valve cover, the packing gland and the valve rod; a valve rod metal sealing assembly is arranged in the sealing cavity and comprises a self-sealing thrust pad, a high-temperature sealing piece located on the upper portion of the self-sealing thrust pad and a low-temperature sealing piece located on the lower portion of the self-sealing thrust pad. The all-metal valverod sealing mechanism adopts the sealing assembly made of all-metal materials, thus the great sealing effect can still be achieved under the conditions of 35 MPa or above of ultra-high pressure and the extreme high and low temperature, the sealing assembly made of the metal materials does not lose efficacy under the conditions of the continuous high temperature, strong acid alkaline and oxygen containing, the applicable range of a valve is expanded further, the using safety of the valve is ensured, and the service life of the valve is prolonged.

Description

technical field [0001] The invention relates to the technical field of slab gate valves, in particular to an all-metal valve stem sealing mechanism and a slab gate valve comprising the all-metal valve stem sealing mechanism. Background technique [0002] The seals used in the existing flat gate valves in China are all non-metallic seals. Due to their own material characteristics (application temperature, fatigue aging characteristics, etc.), the application range of this type of valve is greatly limited, and the service life cannot meet the site requirements. At least It has two main disadvantages: [0003] One is that the stem seal and seat seal of the existing flat gate valve generally use non-metallic materials such as PTFE (polytetrafluoroethylene) or PEEK (polyether ether ketone), which will be obviously Failure, loss of sealing function; similarly, at high pressure and low temperature (temperature below minus 60°C, pressure above 20MPa), it will obviously fail, lose s...

AI Technical Summary

Problems solved by technology

[0002] The seals used in the existing flat gate valves in China are all non-metallic seals. Due to their own material characteristics (application temperature, fatigue aging characteristics, etc.), the application range of this type of valve is greatly limited, and the service life cannot meet the site requirements. At least It has two main disadvantages:

[0003] One is that the stem seal and seat seal of the existing flat gate valve generally use non-metallic materials such as PTFE (polytetrafluoroethylene) or PEEK (polyether ether ketone), which will be obviously Failure, loss of sealing function; similarly, at high pressure and low temperature (temperature below minus 60°C, pressure above 20MPa), it will obviously fail, lose sealing function, and even cause safety accidents;

[0004] Second, due to the use of non-metallic seals in the existing slab gate valve, the slab gate valve has a strong sensitivity to the working medium. For example, in the case of continuous high temperature, strong acid, alkali, and oxygen, PTFE and other materials will be damaged. A certain degree of aging or even weathering will seriously affect the use of the valve and even cause safety accidents

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