Sealing structure of low-pressure bypass valve

Abstract

The utility model relates to the technical field of low-pressure bypass valves, in particular to a low-pressure bypass valve sealing structure which comprises a valve body, a valve cage arranged in the valve body and a valve rod with one end extending into the valve cage. The main valve element is connected into the valve cage in an up-down sliding mode, the balance structure is used for connecting the end of a valve rod and the main valve element, the valve seat is installed at the bottom end of the valve cage, the bottom face of the main valve element is a plane, and when the valve is in an open state, the open hole is formed below the bottom face of the main valve element; according to the utility model, the situation that the main valve core impacts the valve seat to cause damage to the main sealing pair of the valve seat can be avoided, the situation that high-speed steam flow impacts the sealing surface of the valve core to cause damage to the sealing surface of the valve core when the valve is opened can also be avoided, and the normal use of the valve is ensured.

Description

Technical Field

[0001] This utility model relates to the field of low-pressure bypass valve technology, specifically a low-pressure bypass valve sealing structure. Background Technology

[0002] like Figure 1 As shown, the existing low-pressure bypass valve seat 101 is a welded fixed seat 101. The closing speed of the main valve core 102 is uncontrollable, which can easily lead to damage to the main sealing pair of the valve seat 101 caused by the main valve core 102 impacting the valve seat 101. In addition, when the valve is opened, the valve core sealing surface 1020 of the main valve core 102 forms a 45° angle with the valve centerline. The valve core sealing surface 1020 is directly opposite the opening 1031 on the valve cage 103. When the valve is opened, wet steam forms high-speed steam flows through the opening 1031 on the valve cage 103. The high-speed steam flow impacts the sealing surface 1020, which not only damages the sealing surface 1020, but also damages the bottom plane 204 of the main valve core 102 under the erosion of the airflow, affecting the normal use of the valve. Utility Model Content

[0003] The purpose of this utility model is to address the above-mentioned shortcomings by providing a low-pressure bypass valve sealing structure that can not only avoid damage to the main sealing pair of the valve seat caused by the main valve core hitting the valve seat, but also avoid damage to the valve core sealing surface caused by the high-speed steam flow impacting the valve core sealing surface when the valve is opened, thus ensuring that the valve can be used normally.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A low-pressure bypass valve sealing structure includes a valve body, a valve cage disposed within the valve body, a valve stem extending one end into the valve cage, and a plurality of openings radially disposed on the valve cage communicating with the inside and outside of the valve cage. The structure is characterized by: a main valve core slidably connected vertically within the valve cage; a balance structure used to connect the valve stem end to the main valve core; a valve seat installed at the bottom end of the valve cage; and the bottom surface of the main valve core being a plane. When the valve is in the open state, the openings are located below the bottom surface of the main valve core.

[0006] Furthermore, the main valve core is coaxially provided with holes one, two, and three opposite to the valve stem, and the outer diameters of holes one, two, and three gradually decrease; the balancing structure includes a pre-start valve core fixed to the end of the valve stem, the shape of the pre-start valve core is adapted to hole one, and multiple disc springs are provided in hole two, with the two ends of the disc springs respectively connected to the pre-start valve core and the main valve core.

[0007] Furthermore, a Stellite alloy layer is welded onto the sealing surface of the main valve core.

[0008] Furthermore, the plane is axially recessed inward to form an indentation.

[0009] Furthermore, the valve seat is fixed to the bottom of the valve cage by bolts.

[0010] The beneficial effects of this utility model are:

[0011] In practical applications, the closing speed of the main valve core is adjusted by a balancing structure to prevent damage to the main valve seat sealing pair caused by the main valve core impacting the valve seat. When the valve is opened, the opening is located below the bottom surface of the main valve core, and the high-speed steam flow direction is consistent with the plane direction of the bottom of the main valve core, protecting the integrity of the sealing surface. This invention not only avoids damage to the main valve seat sealing pair caused by the main valve core impacting the valve seat, but also avoids damage to the valve core sealing surface caused by the high-speed steam flow impacting the valve core sealing surface when the valve is opened, ensuring the normal operation of the valve. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of a low-pressure bypass valve in the prior art;

[0013] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;

[0014] Figure 3 This is a schematic diagram of the structure of this utility model;

[0015] Figure 4 yes Figure 3 A magnified view of a section at point B in the middle;

[0016] Reference numerals: Valve seat 101; Main valve core 102; Sealing surface 1020; Hole 1 1021; Hole 2 1022; Hole 3 1023; Valve cage 103; Opening 1031; Valve body 201; Valve stem 202; Balancing structure 203; Pre-opening valve core 2031; Disc spring 2032; Flat surface 204; Recessed surface 2041. Detailed Implementation

[0017] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, a low-pressure bypass valve sealing structure includes a valve body 201, a valve cage 103 disposed within the valve body 201, a valve stem 202 with one end extending into the valve cage 103, and a plurality of openings 1031 radially disposed on the valve cage 103 communicating with the inside and outside of the valve cage 103. The structure is characterized by: a main valve core 102 slidably connected vertically within the valve cage 103; a balance structure 203 used to connect the end of the valve stem 202 to the main valve core 102; a valve seat 101 installed at the bottom of the valve cage 103; and a bottom surface of the main valve core 102 being a plane 204. When the valve is in the open state, the openings 1031 are located below the bottom surface of the main valve core 102.

[0018] During use, the closing speed of the main valve core 102 is adjusted by the balancing structure 203 to avoid damage to the main sealing surface of the valve seat 101 caused by the main valve core 102 impacting the valve seat 101. When the valve is opened, since the opening 1031 is located below the bottom surface of the main valve core 102 and the high-speed steam flow direction is consistent with the plane 204 of the bottom of the main valve core 102, the integrity of the sealing surface 1020 is protected. This utility model can not only avoid damage to the main sealing surface of the valve seat 101 caused by the main valve core 102 impacting the valve seat 101, but also avoid damage to the valve core sealing surface 1020 caused by the high-speed steam flow impacting the valve core sealing surface 1020 when the valve is opened, thus ensuring that the valve can be used normally.

[0019] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the main valve core 102 is coaxially provided with holes 1021, 1022, and 1023 opposite to the valve stem 202, and the outer diameters of holes 1021, 1022, and 1023 gradually decrease; the balance structure 203 includes a pre-opening valve core 2031 fixed to the end of the valve stem 202, the shape of which is adapted to hole 1021, and hole 2022 is provided with... A multi-leaf disc spring 2032 is provided, with its two ends connected to the pre-opening valve core 2031 and the main valve core 102, respectively. In this embodiment, since a disc spring 2032 is provided between the pre-opening valve core 2031 and the main valve core 102, the pre-opening valve core 2031 is kept open by the supporting force of the disc spring 2032 during the entire valve closing process, so that the closing speed of the main valve core 102 is controllable and the main sealing pair is avoided from being damaged by the main valve core 102 hitting the valve seat 101.

[0020] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, a Stellite alloy layer is welded onto the sealing surface 1020 of the main valve core 102. In this embodiment, the Stellite alloy layer can improve the erosion resistance of the sealing surface 1020, as well as increase the hardness of the sealing surface 1020 and improve the valve sealing performance.

[0021] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the plane 204 is recessed inward axially to form an indentation 2041. In this embodiment, the indentation 2041 can prevent the steam from eroding the sealing surface 1020 when the valve is open at a small degree, and prevent the moisture in the unsaturated steam from causing "water erosion" damage to the sealing surface 1020 when the machine is started, thus significantly improving the service life of the sealing pair.

[0022] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the valve seat 101 is fixed to the bottom of the valve cage 103 by bolts; in this embodiment, fixing the valve seat 101 to the bottom of the valve cage 103 by bolts makes it more convenient to inspect, maintain and replace the valve seat 101.

[0023] The specific embodiments described herein are merely illustrative examples of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the scope defined by this utility model.

Claims

1. A low-pressure bypass valve sealing structure, comprising a valve body, a valve cage disposed within the valve body, a valve stem extending one end into the valve cage, and a plurality of openings radially disposed on the valve cage communicating with the inside and outside of the valve cage, characterized in that: The main valve core is slidably connected inside the valve cage. The balance structure used to connect the valve stem end and the main valve core is installed on the valve seat at the bottom of the valve cage. The bottom surface of the main valve core is flat. When the valve is in the open state, the opening is located below the bottom surface of the main valve core.

2. The low-pressure bypass valve sealing structure according to claim 1, characterized in that, The main valve core is coaxially provided with holes one, two, and three opposite to the valve stem, and the outer diameters of holes one, two, and three gradually decrease; the balancing structure includes a pre-opening valve core fixed to the end of the valve stem, the shape of which is adapted to hole one, and multiple disc springs are provided in hole two, with the two ends of the disc springs connected to the pre-opening valve core and the main valve core, respectively.

3. The low-pressure bypass valve sealing structure according to claim 1, characterized in that, A Stellite alloy layer is welded onto the sealing surface of the main valve core.

4. The low-pressure bypass valve sealing structure according to claim 1, characterized in that, The plane is recessed inward along its axial direction to form an indentation.

5. The low-pressure bypass valve sealing structure according to claim 1, characterized in that, The valve seat is fixed to the bottom of the valve cage by bolts.

Images