Pneumatic stop valve

Abstract

The utility model relates to the technical field of stop valves, in particular to a pneumatic stop valve which comprises a valve body, a valve seat, a valve rod and a valve clack assembly, the valve seat is arranged in the valve body, and the valve seat is provided with a valve seat contact conical surface; the valve rod extends into the valve body and can ascend and descend in the valve body. The valve clack assembly is arranged at the end, extending into the valve body, of the valve rod, the valve clack assembly comprises a large valve clack, the large valve clack is provided with a first guide arc-shaped surface which is sunken in the direction away from the valve seat, and the first guide arc-shaped surface is matched with the contact conical surface of the valve seat. The contact surface of the valve clack and the valve body adopts a guide contact structure, so that the operation reliability of the valve clack is improved.

Description

Technical Field

[0001] This utility model relates to the field of shut-off valve technology, specifically a pneumatic shut-off valve. Background Technology

[0002] A pneumatic shut-off valve is a control component used for cutting off, distributing, and changing the flow direction of a medium. The opening and closing element of a pneumatic shut-off valve is a plug-shaped valve disc that moves linearly along the centerline of the fluid. The valve stem movement can be either a rising stem type (the valve stem rises and falls, but the handwheel does not) or a rising and rotating stem type (the handwheel and valve stem rotate and rise together, with the nut located on the valve body). Shut-off valves are only suitable for fully open and fully closed operation and are not permitted for regulation or throttling.

[0003] With the continuous growth of my country's demand for clean energy, nuclear power in my country has entered a new stage of simultaneous development of safety, independent development and the upgrading of third-generation nuclear power technology. This has led to the continuous updating and iteration of the structure and function of nuclear-grade large-diameter shut-off valves used in nuclear power technology. Utility Model Content

[0004] In view of the deficiencies of the prior art, this utility model provides a pneumatic shut-off valve, in which the valve disc and valve body contact surface adopt a guide contact structure, which improves the reliability of valve disc operation.

[0005] To achieve the above objectives, the present invention provides a pneumatic shut-off valve, comprising a valve body, a valve seat, a valve stem, and a valve disc assembly. The valve seat is disposed inside the valve body and has a valve seat contact cone surface. The valve stem extends into the valve body and can move up and down within the valve body. The valve disc assembly is disposed at the end of the valve stem that extends into the valve body. The valve disc assembly includes a large valve disc, which has a first guide arc surface recessed away from the valve seat and a valve disc contact cone surface that connects to and smoothly transitions with the first guide arc surface. The valve disc contact cone surface cooperates with the valve seat contact cone surface.

[0006] Furthermore, the valve seat contact cone surface is overlaid with a first medium layer, and the valve disc contact cone surface is overlaid with a second medium layer with a hardness greater than that of the first medium layer.

[0007] Furthermore, the large valve disc is fixed with a large valve disc pressure sleeve to form a cavity inside the large valve disc, the valve stem extends into the cavity and connects with the small valve disc, and the small valve disc and the large valve disc are sealed with a conical surface.

[0008] Furthermore, the small valve disc is welded with a third medium layer, and the large valve disc is welded with a fourth medium layer with a hardness lower than the third medium layer, and the third medium layer and the fourth medium layer are in contact and sealed.

[0009] Furthermore, the valve stem is equipped with a valve position indicator.

[0010] Furthermore, the valve body is fitted with a valve cover, and a spiral wound gasket is provided between the valve body and the valve cover.

[0011] Furthermore, the valve body is fitted with a valve cover, the valve stem passes through the valve cover, and a packing seal assembly is provided between the valve stem and the valve cover.

[0012] Furthermore, the area where the valve stem contacts the packing seal assembly is set as a working surface after calendering.

[0013] Furthermore, the packing seal assembly includes two flexible graphite braided rings disposed on the outside of the valve stem, and a flexible graphite ring confined between the two flexible graphite braided rings.

[0014] Furthermore, the packing pressure plate is fixed to the valve cover by packing studs and the packing sealing assembly is pressed by the packing pressure sleeve;

[0015] A disc spring is provided between the packing stud and the packing pressure plate, the disc spring is provided with a disc spring indicator needle, and the packing pressure plate is provided with a disc spring indicator disc.

[0016] The beneficial effects of this utility model are as follows: a first guide arc surface and a valve disc contact cone surface that connects and smoothly transitions with it are provided. The valve disc contact cone surface and the valve seat contact cone surface cooperate to form a guide contact structure, which improves the reliability of valve disc operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a pneumatic shut-off valve in one embodiment of the present invention;

[0018] Figure 2 This is a partial sectional view of the side of a pneumatic shut-off valve in one embodiment of the present invention;

[0019] Figure 3 for Figure 1 Enlarged view of a section at point III;

[0020] Figure 4 for Figure 1 Enlarged view of a section at point IV;

[0021] Figure 5 for Figure 1 A magnified view of section V;

[0022] Figure 6 for Figure 1 A magnified view of a section at point VI;

[0023] Figure 7 This is a schematic diagram of the structure of the packing sealing assembly in one embodiment of the present invention;

[0024] Figure 8 for Figure 2 A schematic diagram of the valve position indicator area A.

[0025] Figure 9 for Figure 2 BB section view;

[0026] In the picture:

[0027] 100. Valve body,

[0028] 200. Valve seat; 210. Valve seat contact cone surface; 211. First medium.

[0029] 300. Valve stem; 310. Valve position indicator; 320. Valve stem connecting nut; 330. Anti-loosening washer.

[0030] 400. Valve disc assembly; 410. Large valve disc; 411. First guide arc surface; 412. Fourth medium layer; 413. Valve disc contact cone surface; 4131. Second medium layer; 420. Large valve disc sleeve; 430. Small valve disc; 431. Third medium layer; 440. Small valve disc sleeve; 450. Split ring; 460. Anti-rotation pin.

[0031] 500. Valve cover; 510. Spiral wound gasket; 520. Middle flange bolts; 530. Middle flange nuts.

[0032] 600. Packing seal assembly; 610. Flexible graphite braided ring; 620. Flexible graphite ring; 630. Packing pressure plate; 640. Packing stud; 650. Packing sleeve; 660. Disc spring; 670. Disc spring indicator needle; 680. Disc spring indicator disc.

[0033] 700. Bracket; 710. Limit switch bracket; 711. Moving magnetic pole position indicator; 712. Stationary magnetic pole position indicator.

[0034] 800. Pneumatic device

[0035] 900. Solenoid valve. Detailed Implementation

[0036] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0037] See Figure 1 , Figure 3 , Figure 4 and Figure 5 The diagram shows a schematic of a pneumatic shut-off valve according to an embodiment of the present invention. The valve includes a valve body 100, a valve seat 200, a valve stem 300, and a valve disc assembly 400. The valve seat 200 is disposed inside the valve body 100 and has a valve seat contact cone surface 210. The valve stem 300 extends into the valve body 100 and can move up and down within the valve body 100. The valve disc assembly 400 is disposed at the end of the valve stem 300 extending into the valve body 100. The valve disc assembly 400 includes a large valve disc 410, which has a first guide arc-shaped surface 411 recessed away from the valve seat 200 and a valve disc contact cone surface 413 connected to the first guide arc-shaped surface 411. The valve disc contact cone surface 413 cooperates with the valve seat contact cone surface 210.

[0038] The aforementioned pneumatic shut-off valve features a first guide arc-shaped surface 411 and a valve disc contact cone surface 413 that smoothly connects and transitions with the large valve disc 410. The valve disc contact cone surface 413 mates with the valve seat contact cone surface 210, forming a guide contact structure that improves the reliability of valve disc operation. Additionally, as... Figure 3 As shown, the first guide arc-shaped surface 411 is concave in the direction away from the valve seat 200, and has a streamlined shape. When the valve is opened or closed, the first guide arc-shaped surface 411 can guide the fluid. Figure 1 The arrows in the diagram indicate the direction of medium flow, which can reduce the impact of fluid on the valve disc and valve body to a certain extent, extend the service life of the valve, and at the same time facilitate the mutual guidance and cooperation between the valve disc contact cone surface 413 and the valve seat contact cone surface 210.

[0039] See Figure 2 In this embodiment, the valve body 100 adopts an integral casting structure, which reduces welds or sealing joints, ensuring reliable sealing, a compact structure, and uniform wall thickness. During use, the valve exhibits good fatigue resistance and strong deformation resistance, improving the overall vibration resistance of the device. The valve body cavity and flow channel design have undergone flow field analysis to ensure that the valve's flow capacity requirements are met. No graphite sealing ring is required between the valve seat 200 and the valve body 100, simplifying the structure.

[0040] See Figure 3 In one embodiment, the valve seat contact cone surface 210 is overlaid with a first medium layer 211, and the valve disc contact cone surface 413 is overlaid with a second medium layer 4131 with a hardness greater than that of the first medium layer 211. In this embodiment, the first medium layer 211 is a cobalt-based alloy ERCoCr-A with a thickness greater than or equal to 3 mm and a hardness of HRC39~43. Correspondingly, the second medium layer 4131 is a cobalt-based alloy ERCoCr-A with a thickness greater than or equal to 3 mm and a hardness of HRC43~47.

[0041] The valve disc assembly 400 and valve seat 200 of the aforementioned pneumatic shut-off valve employ a conical seal, ensuring excellent sealing performance. Furthermore, although the valve seat contact cone surface 210 is made of hard alloy weld overlay, and the large valve disc 410 is also a hard alloy weld overlay structure, a certain hardness difference exists between the first medium layer 211 welded to the valve seat contact cone surface 210 and the second medium layer 4131 welded to the valve disc contact cone surface 413. This ensures sealing performance while preventing the large valve disc 410 from seizing or sticking to the valve seat 200. The hard alloy sealing surface enhances wear resistance and extends the valve's service life.

[0042] In one embodiment, a large valve disc 410 is fixed with a large valve disc sleeve 420 to form a cavity within the large valve disc 410. A valve stem 300 extends into the cavity and connects to a small valve disc 430. A conical seal is used between the small valve disc 430 and the large valve disc 410.

[0043] like Figure 4 As shown, in one embodiment, the small valve disc 430 is welded with a third medium layer 431, and the large valve disc 410 is welded with a fourth medium layer 412 with a hardness lower than that of the third medium layer 431. The third medium layer 43 and the fourth medium layer 412 are in contact and sealed. In this embodiment, the third medium layer 431 is ERCoCr-A with a thickness greater than or equal to 3 mm and a hardness of HRC43~47. Correspondingly, the fourth medium layer 412 is ERCoCr-A with a thickness greater than or equal to 3 mm and a hardness of HRC39~43.

[0044] It should be noted that, similar to the contact seal between valve seat 200 and large valve disc 410, the third medium layer 431 welded onto small valve disc 430 and the fourth medium layer 412 welded onto large valve disc 410 form a certain hardness difference to ensure sealing and prevent small valve disc 430 and large valve disc 410 from seizing or sticking together. The hard alloy sealing surface can enhance wear resistance and further extend the service life of the valve.

[0045] In specific settings, such as Figure 1 As shown, the small valve disc 430 is connected to the valve stem 300 in such a way that the valve stem 300 is inserted into the small valve disc 430, and the two are nested together. The small valve disc pressure sleeve 440 abuts the end of the valve stem 300 against the bottom wall of the middle cavity of the small valve disc 430 through the split ring 450. An anti-rotation pin 460 is provided between the end of the valve stem 300 and the bottom wall to prevent relative rotation between the valve stem 300 and the small valve disc 430.

[0046] Figure 1 Combination Figure 8 and Figure 9In one embodiment, the valve stem 300 is equipped with a valve position indicator 310. A limit switch bracket 710 is mounted on the upper part of the valve cover 500. The limit switch bracket 710 is respectively equipped with a moving magnetic pole position indicator 711 and a stationary magnetic pole position indicator 712. The moving magnetic pole position indicator (model EA120-10001) 711 and the stationary magnetic pole position indicator 712 (model EA120-12000 / EC390-44035T) cooperate with the valve position indicator 310 to indicate the valve position. Furthermore, the pneumatic circuit is controlled by a solenoid valve 900 mounted on the pneumatic device 800. This bidirectional contactless valve position indication design in both open and closed positions meets the requirements of next-generation nuclear power technology.

[0047] like Figure 1 As shown, in one embodiment, the valve body 100 is equipped with a valve cover 500, and a spiral wound gasket 510 is provided between the valve body 100 and the valve cover 500. With this configuration, the valve cover 500 and the valve body 100 are connected by a spiral wound gasket 510 in conjunction with a middle flange bolt 520 and a middle flange nut 530, which can ensure a more reliable seal.

[0048] In one embodiment, the valve stem 300 passes through the valve cover 500, and a packing seal assembly 600 is provided between the valve stem 300 and the valve cover 500.

[0049] In one embodiment, the area where the valve stem 300 contacts the packing seal assembly 600 is set as a calendered working surface.

[0050] It should be noted that in this embodiment, the working area of ​​the valve stem 300 in contact with the packing is finished and then troweled to reduce surface roughness, reduce switching force, and thus improve the packing's sealing performance and service life. Specifically, the minimum cross-sectional area of ​​the valve stem 300 meets the maximum driving force requirement of the pneumatic device. Furthermore, the design of the valve stem 300 must meet the requirements for a slenderness ratio.

[0051] like Figure 7 As shown, in one embodiment, the packing seal assembly 600 includes two flexible graphite braided rings 610 disposed on the outside of the valve stem 300, and a flexible graphite ring 620 confined between the two flexible graphite braided rings 610. The valve stem 300 is sealed with packing material, which is molded. The flexible graphite braided rings 610 clamp the middle flexible graphite ring 620, which prevents the packing material from being extruded and facilitates its removal.

[0052] See Figure 6In one embodiment, the packing pressure plate 630 is fixed to the valve cover 500 by the packing stud 640 and the packing sealing assembly 600 is pressed by the packing sleeve 650; a disc spring 660 is provided between the packing stud 640 and the packing pressure plate 630, the disc spring 660 is provided with a disc spring indicator needle 670, and the packing pressure plate 630 is provided with a disc spring indicator disc 680.

[0053] A bracket 700 is provided on the upper part of the valve cover 500 of the pneumatic shut-off valve. A pneumatic device 800 is fixed on the upper part of the bracket 700. The drive rod of the pneumatic device 800 is connected to the valve stem 300 through a valve stem connecting nut 320. Preferably, an anti-loosening washer 330 is provided between the drive rod and the valve stem connecting nut 320. The coupling between the drive rod of the pneumatic device 800 and the valve stem 300, i.e., the valve stem connecting nut 320, is designed to be disengaged in the valve de-energized mode and during air purging. This allows for repair and seal replacement of the drive rod of the pneumatic device 800 without removing the pneumatic assembly, making it easy to operate.

[0054] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0056] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0057] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature. It should be noted that when an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "above," "below," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

Claims

1. A pneumatic globe valve characterized by: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

2. A pneumatic globe valve according to claim 1, characterized in that: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

3. A pneumatic globe valve according to claim 1, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

4. A pneumatic globe valve according to claim 3, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

5. A pneumatic globe valve according to claim 1, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

6. A pneumatic globe valve according to claim 1, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

7. A pneumatic globe valve according to claim 1, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

8. A pneumatic globe valve according to claim 7, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

9. A pneumatic globe valve according to claim 7, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle.

10. A pneumatic globe valve according to claim 7, wherein: The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility model relates to a valve body, a valve seat, a valve stem, a valve clapper assembly, a valve position indicator, a valve cover, a packing seal assembly, a packing gland, a packing gland pressing plate, a packing screw post, a disc spring and a disc spring indicator needle. The utility

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