Sealing structure of gate valve stuffing box

Abstract

The invention relates to a sealing structure of a gate valve stuffing box. The sealing structure comprises a valve deck, wherein a gland is arranged on the valve deck, the stuffing box is arranged in the valve deck, and stuffing is filled in the stuffing box. A protrusion for pressing the stuffing is arranged on the gland, a valve rod is located in the valve deck and penetrates through the stuffing and the gland, the vertical section of the stuffing box is conical, and the end surface of the stuffing box close to the gland is larger than the end surface of the stuffing box far away from the gland. When the gland presses the stuffing, as the vertical section of the stuffing box is conical, the stuffing bears not only downward pressure but also radial extruding force under the effect of the conical stuffing box, so that the stuffing tightly contacts the valve rod, a good sealing effect is achieved, and accordingly leakage of media through the stuffing box is avoided.

Description

technical field [0001] The invention relates to a valve sealing structure, in particular to a gate valve stuffing box sealing structure. Background technique [0002] With the rapid development of science and technology and the continuous improvement of the level of the petroleum industry, the requirements for the sealing of valves are getting higher and higher. Once the valve leaks, it will cause serious consequences. The leakage of the valve can be divided into internal leakage and external leakage. The internal leakage occurs on the sealing pair of the valve seat and the closing member, and the external leakage occurs on the sealing pair of the valve stem seal and the connecting flange. The factors that cause external leakage are: 1. The packing seal only relies on the gland to apply axial force to it, and then produces radial extrusion deformation to seal the valve stem to prevent the medium from leaking out. 2. The shape of the filler is rectangular. According to the...

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Problems solved by technology

2. The shape of the packing is rectangular. From the analysis of actual use, the ability of the rectangular packing to resist extrusion and wear is mutually restricted, and the sealing effect is poor.

3. The filler is generally made of asbestos tape weaving or expanded graphite, which has good self-lubrication and thermal conductivity, small friction coefficient, but poor elasticity, poor compensation performance after wear, and unsatisfactory sealing effect

4. The inner cavity of the stuffing box of the bonnet adopts a cylindrical shape, which cannot ensure that the packing is installed in the sealing cavity in parallel, and the packing is unevenly distributed around the valve stem, which is easy to be squeezed to cause eccentric wear, which reduces the service life of the packing

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