Under-pressure sealing device for vacuum system of power plant

Abstract

The utility model relates to the technical field of power plant equipment, and particularly discloses a power plant vacuum system under-pressure sealing device which comprises a first semicircular sealing piece and a second semicircular sealing piece which are detachable. A stepped groove is formed in the second semi-annular sealing piece; an inner side sealing groove is formed in the stepped groove; the inner side sealing groove is filled with a second graphite packing; the detachable first semi-annular sealing piece and the detachable second semi-annular sealing piece are fixed to a steam turbine shaft seal expansion joint and a shaft seal body flange, and then the contact area between the inner side sealing groove and the steam turbine shaft seal expansion joint and the contact area between the inner side sealing groove and the shaft seal body flange are increased. The second graphite packing is extruded between the first semi-annular sealing piece and the steam turbine shaft seal expansion joint and between the second semi-annular sealing piece and the shaft seal body flange to seal the joint of the steam turbine shaft seal expansion joint and the shaft seal body flange, sealing treatment under high strength and high pressure is achieved, and the problem that an existing original sealing device is poor in sealing performance is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of power plant equipment, and specifically relates to a pressure - sealed device for a power plant vacuum system. Background Technique

[0002] The function of the power plant vacuum system is to reduce the exhaust pressure of the steam turbine to form a high vacuum, so as to increase the ideal enthalpy drop of the steam in the steam turbine and increase the work done by the steam in the steam turbine. The establishment of the vacuum in the vacuum system originates from the vacuum pump. The function of the vacuum pump is used for the two processes of evacuating the condenser of the power plant and maintaining the vacuum. During the evacuation stage, during the initial evacuation when steam is not introduced into the condenser, the air and other non - condensable gases in the condenser are pumped out. During the vacuum maintenance stage, during the operation of the condenser, the vacuum pump continues to work to pump out the non - condensable gases such as air and steam leaking into the condenser, maintain the vacuum in the condenser, ensure the efficient operation of the steam turbine, and improve the thermal efficiency of the power plant.

[0003] At the same time, the vacuum system is a huge system composed of various different equipment such as condensers, drain pipes, and containers. The tightness of the system directly affects the heat transfer effect of the condenser and the efficiency of the steam turbine.

[0004] However, the above - disclosed solutions have the following deficiencies: An important indicator of the power plant vacuum system is the vacuum tightness. Maintaining good vacuum tightness during operation is beneficial to improving the heat transfer efficiency of the condenser and the absolute vacuum degree of the condenser. At the same time, the condenser vacuum system is a huge system composed of condensers and connected pipes, valves and other equipment. Some welds and flanges have certain leakage points due to construction technology and design defects. Among them, the leakage problem at the connection surface between the steam turbine shaft seal expansion joint and the shaft seal body flange occurs occasionally, which will reduce the overall sealing performance and needs to be modified to maintain the sealing performance. Content of the Utility Model

[0005] The purpose of the utility model is to solve the technical problem that the leakage problem at the connection surface between the steam turbine shaft seal expansion joint and the shaft seal body flange occurs occasionally, which will reduce the overall sealing performance and needs to be modified to maintain the sealing performance, and provides a pressure - sealed device for a power plant vacuum system.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions to be realized;

[0007] A pressure - sealed device for a power plant vacuum system described in the utility model includes a detachable first semi - circular seal and a second semi - circular seal; a stepped groove is provided on the second semi - circular seal; an inner seal groove is provided in the stepped groove; a second graphite packing is filled in the inner seal groove; a plurality of glue injection holes are spaced apart on the second semi - circular seal.

[0008] Further, a side seal groove is provided on the second semi-circular seal; the side seal groove is filled with a first graphite packing.

[0009] Further, first mid-plane symmetric plates are symmetrically and fixedly connected to the first semi-circular seal; second mid-plane symmetric plates are symmetrically and fixedly connected to the second semi-circular seal.

[0010] Further, a nut pair is inserted through holes in the second mid-plane symmetric plate and the first mid-plane symmetric plate.

[0011] Further, the first semi-circular seal and the first mid-plane symmetric plate are integrally formed by steel plate cutting; the second semi-circular seal and the second mid-plane symmetric plate are integrally formed by steel plate cutting.

[0012] Further, the injection holes are distributed at intervals of thirty degrees around the axis of the second semi-circular seal.

[0013] A pressure sealing device for a power plant vacuum system provided by the present utility model has the following beneficial effects:

[0014] 1. The present utility model is fixed at the steam turbine shaft seal expansion joint and the shaft seal body flange through the detachable first semi-circular seal and the second semi-circular seal, and then the inner seal groove is used to increase the contact area with the steam turbine shaft seal expansion joint and the shaft seal body flange. The second graphite packing is squeezed between the first semi-circular seal, the second semi-circular seal and the steam turbine shaft seal expansion joint and the shaft seal body flange to seal the connection between the steam turbine shaft seal expansion joint and the shaft seal body flange. Then, a large amount of sealing glue is evenly injected through the injection holes, so that the sealing effect at the connection between the second graphite packing and the steam turbine shaft seal expansion joint and the shaft seal body flange is better, realizing the sealing treatment under high strength and high pressure, and solving the problem of poor sealing performance of the existing original sealing device;

[0015] 2. The present utility model can perform double-layer sealed connection on the steam turbine shaft seal expansion joint and the shaft seal body flange through the first graphite packing cooperating with the side seal groove, solving the problem of poor sealing performance at the steam turbine shaft seal expansion joint and the shaft seal body flange in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following further describes in detail the specific embodiments of the present utility model in conjunction with the drawings;

[0017] Figure 1 is the first axonometric structure schematic diagram of the present utility model;

[0018] Figure 2 is the second axonometric structure schematic diagram of the present utility model;

[0019] Figure 3 is the top view structure schematic diagram of the present utility model.

[0020] Description of reference numerals in the figure: 1. First semi-circular seal; 2. First symmetrical plate of the middle parting surface; 3. Nut pair; 4. Second symmetrical plate of the middle parting surface; 5. Step groove; 6. Side seal groove; 7. First graphite packing; 8. Inner seal groove; 9. Second graphite packing; 10. Glue injection hole; 11. Second semi-circular seal. Specific embodiments

[0021] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] It should be noted that all directional indications (such as up - down - left - right - front - back...) in the embodiments of the present invention are only used to explain the relative positional relationship - movement conditions, etc. between components in a specific posture (as shown in the accompanying drawings). If this specific posture changes, the directional indications will also change accordingly. The described connection can be a direct connection or an indirect connection.

[0024] Please refer to Figures 1-3 As shown, a pressure - tight sealing device for a power plant vacuum system includes a detachable first semi - circular seal 1 and a second semi - circular seal 11; a step groove 5 is provided on the second semi - circular seal 11; an inner seal groove 8 is provided on the step groove 5; a second graphite packing 9 is filled in the inner seal groove 8; a plurality of glue injection holes 10 are spaced apart on the second semi - circular seal 11; during operation, it is fixed at the steam turbine shaft seal expansion joint and the shaft seal body flange through the detachable first semi - circular seal 1 and the second semi - circular seal 11. Then, the inner seal groove 8 is used to increase the contact area with the steam turbine shaft seal expansion joint and the shaft seal body flange. The second graphite packing 9 is squeezed between the first semi - circular seal 1, the second semi - circular seal 11 and the steam turbine shaft seal expansion joint and the shaft seal body flange to seal the connection between the steam turbine shaft seal expansion joint and the shaft seal body flange. Then, a large amount of sealing glue is evenly injected through the glue injection holes 10, so that the sealing effect between the second graphite packing 9 and the connection of the steam turbine shaft seal expansion joint and the shaft seal body flange is better, realizing the sealing treatment under high strength and high pressure, and solving the problem of poor sealing of the existing original sealing device.

[0025] A side seal groove 6 is provided on the second semi-circular seal 11; a first graphite packing 7 is filled in the side seal groove 6; during operation, through the cooperation of the first graphite packing 7 and the side seal groove 6, double-layer sealing connection can be achieved at the steam turbine shaft seal expansion joint and the shaft seal body flange, solving the problem of poor sealing performance at the existing steam turbine shaft seal expansion joint and the shaft seal body flange.

[0026] A first mid-plane symmetry plate 2 is symmetrically fixed on the first semi-circular seal 1; a second mid-plane symmetry plate 4 is symmetrically fixed on the second semi-circular seal 11; during operation, through the cooperation of the symmetric first mid-plane symmetry plate 2 and the symmetric second mid-plane symmetry plate 4, connection and fixation can be achieved between the steam turbine shaft seal expansion joint and the shaft seal body flange without damaging the inner side circular structure of the first semi-circular seal 1 and the second semi-circular seal 11.

[0027] A nut pair 3 is inserted through holes in the second mid-plane symmetry plate 4 and the first mid-plane symmetry plate 2; during operation, through the nut pair 3, the second mid-plane symmetry plate 4 and the first mid-plane symmetry plate 2 can be conveniently and stably connected to each other, and the device can be stably fixed between the steam turbine shaft seal expansion joint and the shaft seal body flange, solving the problem that the existing sealing device cannot be used under high pressure intensity.

[0028] The first semi-circular seal 1 and the first mid-plane symmetry plate 2 are integrally formed by steel plate cutting; the second semi-circular seal 11 and the second mid-plane symmetry plate 4 are integrally formed by steel plate cutting; during operation, due to the structural parts integrally formed by steel plate cutting, the overall strength is high, and it can be used for a long time without deformation, thus achieving sealing under high-strength and high-pressure conditions, solving the problem that the existing sealing device cannot be used for sealing under high pressure.

[0029] The glue injection holes 10 are distributed at intervals of thirty degrees around the axis of the second semi-circular seal 11; during operation, due to the distribution of the glue injection holes 10 at intervals of thirty degrees around the axis of the second semi-circular seal 11, when glue is injected through the glue injection holes 10, it can be evenly filled in the stepped groove 5, thereby sealing the gap between the second semi-circular seal 11 and the steam turbine shaft seal expansion joint and the shaft seal body flange, forming a sealing structure, and achieving high-strength sealing between the steam turbine shaft seal expansion joint and the shaft seal body flange, solving the problem of poor sealing performance of the existing conventional sealing device.

[0030] With the above solution, when the utility model is in use, it is fixed at the steam turbine shaft seal expansion joint and the flange of the shaft seal body through the detachable first semi-circular seal 1 and the second semi-circular seal 11. Then, the inner seal groove 8 is used to increase the contact area with the steam turbine shaft seal expansion joint and the flange of the shaft seal body. The second graphite packing 9 is squeezed between the first semi-circular seal 1, the second semi-circular seal 11 and the steam turbine shaft seal expansion joint and the flange of the shaft seal body to seal the connection between the steam turbine shaft seal expansion joint and the flange of the shaft seal body, realizing the sealing treatment under high strength and high pressure, and solving the problem of poor sealing of the existing original sealing device; the first graphite packing 7 cooperates with the side seal groove 6 to double-seal and connect the steam turbine shaft seal expansion joint and the flange of the shaft seal body, solving the problem of poor sealing of the existing steam turbine shaft seal expansion joint and the flange of the shaft seal body; through the symmetric first middle split surface symmetric plate 2 cooperating with the symmetric second middle split surface symmetric plate 4, the connection between them is fixed between the steam turbine shaft seal expansion joint and the flange of the shaft seal body without damaging the circular structure of the inner side surfaces of the first semi-circular seal 1 and the second semi-circular seal 11.

[0031] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0032] The above shows and describes the basic principles, main features and advantages of the utility model. Those skilled in the art of this industry should understand that the utility model is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the utility model. Without departing from the spirit and scope of the utility model, the utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the utility model claimed.

Claims

1. A pressure-sealed device for a power plant vacuum system, characterized in that; It includes a detachable first semi-circular seal (1) and a second semi-circular seal (11); a stepped groove (5) is provided on the second semi-circular seal (11); an inner seal groove (8) is provided on the stepped groove (5); a second graphite packing (9) is filled in the inner seal groove (8); a plurality of glue injection holes (10) are spaced apart on the second semi-circular seal (11).

2. The pressure-sealed device for the vacuum system of a power plant according to claim 1, wherein: A side seal groove (6) is provided on the second semi-circular seal (11); a first graphite packing (7) is filled in the side seal groove (6).

3. The pressure-sealing device for the vacuum system of a power plant according to claim 2, wherein: A first middle-part symmetry plate (2) is symmetrically fixed on the first semi-circular seal (1); a second middle-part symmetry plate (4) is symmetrically fixed on the second semi-circular seal (11).

4. The pressure - retaining sealing device for the power plant vacuum system according to claim 3, wherein: A nut pair (3) is inserted through holes in the second middle-part symmetry plate (4) and the first middle-part symmetry plate (2).

5. The pressure-sealed device for the vacuum system of a power plant according to claim 4, wherein: The first semi-circular seal (1) and the first middle-part symmetry plate (2) are integrally formed by steel plate cutting; the second semi-circular seal (11) and the second middle-part symmetry plate (4) are integrally formed by steel plate cutting.

6. The pressure-sealed device for the vacuum system of a power plant according to claim 5, characterized in that: The glue injection holes (10) are distributed at intervals of thirty degrees around the axis of the second semi-circular seal (11).

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