CN201288838Y - Valve seat structure capable of enhancing plate valve first-enveloping pressure - Google Patents

Abstract

A valve seat structure for increasing the initial sealing pressure of a flat gate valve is used for the valve seat of a self-sealing high-pressure flat gate valve, and belongs to the technical field of high-pressure flat gate valve manufacturing. The utility model greatly improves the initial sealing pressure between the valve seat and the gate plate of the self-sealing flat gate valve. The utility model is composed of a valve seat, a sealing ring and a cylindrical helical spring. There are a number of evenly distributed cylindrical holes on one end surface of the valve seat, and a cylindrical coil spring is installed in each hole, and the valve seat with multiple preloaded cylindrical coil springs on the two end surfaces is pressed tightly against the gate plate to form a Compared with the prior art, the annular planar spring has a larger axial force and a larger pre-compression amount, and a more uniform pressure distribution can fully guarantee the initial sealing pressure requirements of the self-sealing flat gate valve.

Description

A valve seat structure for increasing the initial sealing pressure of flat gate valve

Technical field

A valve seat structure for increasing the initial sealing pressure of a flat gate valve is used for the valve seat of a self-sealing high-pressure flat gate valve, and belongs to the technical field of high-pressure flat gate valve manufacturing.

Background technique

In the existing technology, due to the excellent performance of the flat gate valve, there is a tendency to replace the wedge gate valve, especially in oil and gas wellhead devices, due to the action of high-pressure oil and gas, the closing torque of the wedge gate valve is too large, and the sealing surface is easily affected by debris. For particulate pollution, flat gate valves have been widely used instead of wedge gate valves, which tend to be completely eliminated.

Among the widely used types of slab gate valves, the seat self-sealing type is the main one. At present, the defect of self-sealing flat gate valve is poor sealing performance under low pressure, especially for natural gas or other gas pipelines. For this reason, in the standards of the American Petroleum Institute and my country's SY5127-, gate valves are required not only to perform high-pressure air-tightness tests, but also to perform low-pressure air-tightness tests. test. The essence of this problem is that there are sealing devices on the cylindrical surfaces of the two valve seats of the flat gate valve. The lower is equivalent to the hydraulic piston, the greater the pressure, the greater the pressure of the end face of the valve seat on the gate valve plate, and the more reliable the high-pressure seal. If the initial sealing pressure between the valve seat and the plate is too small to leak, and the piston effect cannot be formed, the gate valve cannot be sealed. The disadvantage of the prior art is that the initial pressure between the valve seat and the flat plate is given by an annular flat spring pressed on the end face of the valve seat. Due to the small space, the compressive force of the annular flat spring is small and the deformation is small. Uneven axial pressure defects, therefore, the axial force provided by the valve seat is small, and at the same time, the friction force of the seal on the cylindrical surface of the valve seat must be overcome, so that the initial sealing pressure is even smaller.

The purpose of this utility model is to design a new structure, which can provide a valve seat structure with a sufficiently large axial initial sealing pressure in the current space, so as to ensure the reliability of the air seal of the flat gate valve under low pressure.

Contents of the invention

The utility model is achieved in that the utility model comprises a sealing valve seat and a cylindrical spring. There are 3 to 24 cylindrical holes evenly distributed on one end surface of the sealing valve seat. The depth of the cylindrical holes is consistent. A designed and calculated cylindrical spring is installed in each hole. The total axial pressure of the designed and calculated spring is greater than that of the sealed valve. The requirements for the initial sealing pressure between the seat and the valve plate. The other end of the valve seat is welded heat-resistant and wear-resistant alloy. There are two sealing ring grooves on the outer cylinder of the valve seat, and a sealing ring is installed in the groove. There is one groove on the inner cylinder of the valve seat for installation and disassembly. the installation slot. The valve seat installed on both sides of the gate is under the action of a large axial force of multiple cylindrical springs at the end, so that a large pressure is generated between the valve seat and the gate, so that the gate valve can obtain a reliable initial sealing pressure.

The utility model has the advantages that: the utility model can adopt different numbers of cylindrical springs evenly distributed around the circumference according to the size of the valve seat. Compared with the annular planar springs in the prior art, this structure can provide The axial sealing pressure is much larger. At the same time, due to the pressure generated by a plurality of cylindrical springs with the same characteristics evenly distributed around the circumference, the sealing pressure between the sealing valve seat and the gate plate is evenly distributed. This structure is particularly It is suitable for self-sealing slab gate valves on natural gas wellheads and pipelines that require high sealing performance.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is the structural representation of the utility model;

Fig. 2 is a schematic diagram of the structure of the valve seat of the present invention.

In Figure 1, 1-valve seat; 2-cylindrical spring; 3-sealing ring; 4-gate; 5-flat gate valve body;

In Fig. 2, 6-cylindrical hole on the valve seat; 7-sealing groove on the outer cylindrical surface of the valve seat; 8-alloy layer on the end surface of the valve seat; 9-loading and unloading groove on the inner cylindrical surface of the valve seat.

specific implementation plan

Provide embodiments of the present utility model below in conjunction with accompanying drawing.

The utility model comprises a valve seat 1 and a cylindrical spring 2. A plurality of cylindrical springs 1 according to design requirements are installed in a cylindrical hole on an end surface of the valve seat 1, and a sealing groove 7 is installed in a sealing groove 7 of the outer cylinder of the sealing valve seat. Ring 3, use a special tool to install two identical valve seats in the hole of the body 5 of the flat gate valve, the special tool generates axial tension, pre-compresses multiple cylindrical springs 1 in the cylindrical holes on the end faces of the two sealed valve seats, and then Install the gate between the two sealing valve seats, and then loosen the special tool, so a large spring pressure is generated between the end face of the sealing valve seat and the gate to form the initial sealing pressure. For example, using 8 cylindrical springs, when the compression amount is 5mm, the initial sealing pressure can reach 1.86-2.28MPa, which is in line with the American Petroleum Institute (API) standard and my country's SY5127 standard.

Claims (3)

1. A valve seat structure that increases the initial sealing pressure of a flat gate valve, which includes a sealing valve seat, a sealing ring and a cylindrical helical spring. It is characterized in that: there are 3 to 24 cylindrical holes on one end face of the valve seat, each A cylindrical helical spring is installed in the hole, and there are two sealing grooves on the outer cylindrical surface of the valve seat, and a sealing ring is installed in each groove, and a temperature-resistant and wear-resistant alloy layer is welded on the other end surface of the sealing valve seat. 2. A valve seat structure for increasing the initial sealing pressure of a flat gate valve according to claim 1, wherein the cylindrical holes on the end surface of the sealing valve seat are evenly distributed around the circumference and have the same depth. 3. A valve seat structure for increasing the initial sealing pressure of a slab gate valve according to claim 1, characterized in that the free heights of the cylindrical coil springs are the same, the geometric dimensions are the same, and the preload deformations are the same.

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