CN107288920B - Sealing device and method - Google Patents

Abstract

The present disclosure provides a sealing device and method, wherein the sealing device comprises: the inner surface of the case is respectively provided with at least one layer of first steps, and each layer of first steps is provided with a first grate; and the shaft is arranged along the direction of the casing, at least one layer of second steps are respectively arranged on the outer surface of the shaft, each layer of second steps is provided with a second grate, the first grate teeth and the second grate teeth are distributed in a staggered manner, and the first grate teeth are not contacted with the second grate teeth. The sealing device can be applied to the field of high-pressure high-rotation-speed fluid machinery, achieves a good sealing effect, does not affect the integrated design of the casing, and is convenient for assembling the shaft and the casing.

Description

Sealing devices and methods

Technical field

The present disclosure relates to the fields of fluid machinery, energy power equipment and power generation systems, and in particular, to a sealing device and method.

Background technique

Turbo machinery is a general term for rotating fluid machinery with blades. The common feature of turbine machinery is that the rotor equipped with blades rotates at high speed. When the fluid (gas or liquid) flows through the channel between the blades, a force interaction occurs between the blades and the fluid, thereby achieving energy conversion. According to the different directions of energy conversion, turbomachinery is divided into prime mover and driven machine. The prime mover converts the energy of the fluid (thermal energy, potential energy or kinetic energy) into mechanical energy and drives the generator or other driven machines through the main shaft. Prime movers include steam turbines, gas turbines, turboexpanders, water turbines and wind turbines. The slave is driven by an electric motor or other prime mover to convert mechanical energy into fluid energy, that is, to increase the pressure of the fluid. The driven machines include ventilators, turbine compressors, centrifugal pumps and axial flow pumps, etc. The driven motive and the prime mover are basically the same in principle and structure, but the working process is opposite.

The sealing design of turbine machinery is a very important part of the design. Grate seal is a commonly used sealing structure. Existing grate tooth seal structures generally use straight-through grate tooth seals or ordinary staggered tooth type seals, which will affect the rigidity of the shaft and destroy the overall stability of the machine.

public content

(1) Technical problems to be solved

The purpose of this disclosure is to provide a sealing device and method to solve at least one of the above technical problems.

(2) Technical solutions

According to one aspect of the present disclosure, a sealing device is provided, including: a casing, at least one layer of first steps is provided on the inner surface thereof, and each layer of first steps has a first grate tooth; and a shaft, Placed along the direction of the casing, at least one second step is provided on its outer surface. Each second step has a second grate tooth, and the first grate teeth and the second grate teeth are staggered. Distributed, and the first grate teeth and the second grate teeth do not contact.

In some embodiments of the present disclosure, the first ladder and the second ladder have the same number of layers.

In some embodiments of the present disclosure, the inner surface of the casing is coated with a coating at a position corresponding to the top of the second grate tooth.

In some embodiments of the present disclosure, the coating material includes silver-copper alloy, NiCrAl and/or nickel graphite.

In some embodiments of the present disclosure, one or more ejection parts are provided between the first and second grate teeth that are farthest from the fluid inlet, and the fluid is ejected to the outside and recovered through the ejection parts.

In some embodiments of the present disclosure, the shape of each first grate tooth is the same and the shape of each second grate tooth is the same.

Based on the same concept, the present disclosure also provides a sealing method, which includes: setting at least one layer of first steps on the inner surface of the casing, and each layer of first steps has a first grate tooth; At least one second step is provided on the surface, and each second step has a second grate tooth; and the shaft is placed in the casing along the direction of the casing, and the first grate tooth and the second grate tooth are arranged on the surface. The grate teeth are staggered, and the first grate teeth and the second grate teeth do not contact.

In some embodiments of the present disclosure, the coating is applied on the inner surface of the casing at a position corresponding to the tip of the second grate tooth.

In some embodiments of the present disclosure, one or more ejection parts are provided between the first and second grate teeth that are farthest from the fluid inlet, and the fluid is ejected to the outside and recovered through the ejection parts.

(3) Beneficial effects

Compared with the prior art, the sealing device and method of the present disclosure have at least one of the following advantages:

(1) The sealing device provided by the present disclosure can be used in the field of high-pressure and high-speed fluid machinery, can achieve better sealing effects without affecting the integrated design of the casing, and at the same time facilitates the assembly of the shaft and the casing.

(2) The present disclosure is a universal design that can be used in various turbine machinery, has broad application prospects, complies with design specifications, and is easy to implement in processing technology and assembly.

Description of drawings

Figure 1 is a schematic cross-sectional view of a conventional straight-through grate seal device;

Figure 2 is a schematic cross-sectional view of a common staggered tooth sealing device in the prior art;

Figure 3 is a schematic cross-sectional view of a sealing device according to an embodiment of the present disclosure;

Figure 4 is a schematic cross-sectional view of a sealing device according to a specific embodiment of the present disclosure;

FIG. 5 is a schematic flowchart of steps of a sealing method according to an embodiment of the present disclosure.

Detailed ways

Figure 1 is a schematic cross-sectional view of a conventional straight-through grate seal device. As shown in Figure 1, in the straight-through grate seal device, the surface of the shaft or casing is processed with a grate structure, and the fluid is used to move the grate teeth The top vortex consumes fluid energy to achieve a sealing effect. Although it is easy to assemble, the straight-through grate seal device generally requires multiple grate teeth, which will cause the sealing section to become longer, affecting the stiffness of the shaft, which is not conducive to the design of high-speed rotors. Figure 2 is a schematic cross-sectional view of a common staggered-tooth sealing device in the prior art. As shown in Figure 2, in this common staggered-tooth sealing device, both the shaft and the casing are processed with grate tooth structures. Although the sealing effect is in the straight-through The grate seal device is further strengthened on the basis of the grate seal device. However, when assembling this sealing device, the casing needs to be cut open. Therefore, the casing should be designed as a split type to achieve assembly, which destroys the integrity of the casing and affects the system. stability. It can be seen that the sealing device of the prior art cannot have an excellent sealing effect and a convenient assembly structure at the same time.

In order to make the purpose, technical solutions and advantages of the present disclosure more clear, the present disclosure will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

One aspect of the embodiment of the present disclosure provides a sealing device. Figure 3 is a schematic cross-sectional view of the sealing device of the embodiment of the present disclosure. As shown in Figure 3, the sealing device includes a shaft and a casing. Wherein, the inner surface of the receiver is respectively provided with at least one layer of first steps, and each layer of first steps has a first grate tooth; and

The shaft is placed along the direction of the casing, and its outer surface is provided with at least one second step. Each second step has a second grate tooth. The first grate tooth and the second grate tooth are arranged on the outer surface of the shaft. The teeth are staggered, and the first grate teeth and the second grate teeth do not contact.

Generally speaking, the number of the first step and the second step is the same, that is to say, the number of the first grate teeth and the second grate teeth are the same. According to an embodiment of the present disclosure, in order to facilitate large-scale processing and production, the first grate teeth and the second grate teeth have the same shape, and their arrangement also has the same periodicity. In other embodiments, the first grate teeth The shapes of the grate teeth and the second grate teeth can be different, and their arrangement does not need to be periodic, as long as the first grate teeth and the second grate teeth are staggered and the first grate teeth and the second grate teeth do not contact each other. . In addition, the length of the first step and the second step is not limited and can be designed to any length according to structural needs. In order to make assembly easier, the first step and the second step are generally selected to have the same length.

In order to make the sealing performance of the present disclosure better, in some embodiments, a coating can be coated on the inner surface of the casing at a position corresponding to the tooth top of the second grate tooth, so that the distance between each tooth top and the surface opposite to it is closer. Smaller, better sealing. Among them, the coating material can be silver-copper alloy, NiCrAl and nickel graphite. In order to prevent fluid leakage and other problems, one or more ejection parts can also be provided between the first grate teeth and the second grate teeth farthest from the impeller (fluid inlet). The shape of the ejection parts is not required, and can be Circular holes or other shapes can be set according to actual needs.

Obviously, compared with the straight-through grate seal device shown in Figure 1, the stepped structure of the sealing device shown in Figure 3 of the present disclosure can strengthen the seal while maintaining convenient assembly, and provide better sealing within a limited length. Effect.

Compared with the ordinary staggered tooth sealing device shown in Figure 2, the sealing device shown in Figure 3 has a stepped structure, which can further strengthen the seal without affecting the integrated design of the casing, and is more convenient to assemble.

Figure 4 is a schematic cross-sectional view of a sealing device according to a specific embodiment of the present disclosure. As shown in Figure 4, the upper half of the sealing device (the distance between the upper inner surface of the casing 1 and the upper outer surface of the shaft 2 part) as an example, the lower part (the part between the lower inner surface of the casing 1 and the lower outer surface of the shaft 2) is arranged correspondingly to the upper part, and will not be described again here. The upper part of the sealing device in the embodiment of the present invention includes: a casing 1, with grate teeth 11, 12, and 13 respectively provided on its inner surface, and the three grate teeth are respectively located on three first steps, each of which is Each step has a grate tooth. That is to say, the grate teeth 11 are the first grate teeth on the first step of the first floor, the grate teeth 12 are the first grate teeth on the first step of the second floor, and the grate teeth 13 are the first grate teeth on the first step of the third floor. The first grate tooth. Its upper part also includes a shaft 2, whose outer surface is provided with grate teeth 21, 22, and 23 respectively, and the three grate teeth are respectively located on three second steps, and each second step has one grate tooth, that is, The grate teeth 21 are the second grate teeth on the second step of the first floor, the grate teeth 22 are the second grate teeth on the second step of the second floor, and the grate teeth 23 are the second grate teeth on the second step of the third floor. . The grate teeth on the casing are staggered with the grate teeth on the shaft. The grate teeth 11 and 21, the grate teeth 12 and the grate teeth 22, the grate teeth 13 and the grate teeth 23 cooperate to form a staggered tooth structure. It can be seen that the number of steps of the casing 1 and the shaft 2 is the same and is 3, thus forming a three-step staggered grate structure.

According to an embodiment of the present invention, the coating can be applied on the inner surface of the casing at a position corresponding to the tooth top of the second grate teeth 21, 22 and 23, so that there is a gap between each tooth top and the opposite inner surface of the casing The distance is smaller and the sealing is better.

The part between the first grate teeth 13 and the second grate teeth 23 that is farthest from the impeller 3 (fluid inlet) is provided with one or more ejection parts 4 (such as ejection holes), the shape of which is not limited and can be determined according to actual needs. set up) to direct fluid to the outside and recover it.

Another aspect of the embodiment of the present disclosure also provides a sealing method. Figure 4 is a schematic flow chart of the steps of the sealing method of the embodiment of the present disclosure. As shown in Figure 4, the sealing method includes:

Step S1: Set at least one layer of first steps on the opposite inner surfaces of the casing, and each layer of first steps has a first grate tooth;

Specifically, the inner surface of the casing can be cut or milled using a lathe or the like, thereby obtaining a casing with a stepped grate structure on the inner surface.

Step S2: Set at least one layer of second steps on the opposite outer surfaces of the shaft, and each layer of second steps has a second grate tooth;

Similarly, the shaft can be subjected to cutting or milling processes using a lathe, etc., and the outer surface of the shaft can be processed to obtain a shaft with a stepped grate structure on the outer surface.

Among them, there is no limit to the number of the first steps and the second steps, and they can be designed to any number according to actual sealing requirements. In addition, there is no limit to the length of the steps, and they can be designed to any length according to structural requirements.

Step S3: Place the shaft in the casing along the direction of the casing, the first grate teeth and the second grate teeth are staggered, and the first grate teeth and the second grate teeth do not contact;

Push the shaft with the grate tooth structure on the outer surface along the direction of the casing from the inlet direction of the fluid (the side of the impeller) to the direction of fluid leakage, and place it in the casing with the grate tooth structure on the inner surface. During assembly, a staggered tooth structure is automatically formed: the first grate teeth and the second grate teeth are staggered up and down, and the first grate teeth and the second grate teeth do not contact. Using this stepped staggered tooth structure can not only achieve excellent sealing effect of the staggered tooth structure, but also the receiver can be processed in one piece, making assembly more convenient.

Similarly, in order to make the sealing performance of the present disclosure better, a coating can be applied on the inner surface of the casing at a position corresponding to the top of the second grate tooth. Therefore, the distance between each tooth top and the inner surface of the casing opposite to it can be Smaller and better sealed. Among them, the coating material can be silver-copper alloy, NiCrAl and nickel graphite. In order to prevent fluid leakage, one or more ejection parts can also be provided between the first grate tooth farthest from the impeller (closest to the fluid outlet) and the second grate tooth. The shape of the ejection part is not required, and can be Circular holes or other shapes can be set according to actual needs.

The sealing device obtained by the sealing method of the present disclosure is based on the basic structure of the staggered tooth labyrinth seal and utilizes the stepped staggered tooth structure to cause the sealing fluid to form a vortex in the staggered tooth space, reducing the kinetic energy consumption of the fluid due to gap throttling. Disperse. Since the compressor casing is processed in one piece, it is impossible to assemble the ordinary staggered-tooth labyrinth seal device, so a stepped shaft structure is adopted to realize the assembly of the staggered-tooth seal. Moreover, the fluid produces an obvious throttling effect at the axial grate teeth and the radial step gap, the static pressure drops, and a vortex flow is formed in the staggered tooth space, which reduces the total pressure and achieves a better sealing effect. .

Unless the steps are specifically described or must occur sequentially, the order of the above steps is not limited to those listed above and may be changed or rearranged according to the required design. Moreover, the above-mentioned embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.

Similarly, it should be understood that in the above description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together into a single embodiment in order to streamline the disclosure and assist in understanding one or more of the various disclosed aspects. figure, or its description. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure.

The above-mentioned specific embodiments further describe the purpose, technical solutions and beneficial effects of the present disclosure in detail. It should be understood that the above-mentioned are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this disclosure shall be included in the protection scope of this disclosure.

Claims (7)

1. A sealing device, comprising: The receiver is provided with at least one first step on its inner surface, and each first step has a first grate tooth; and The shaft is placed along the direction of the casing, and its outer surface is provided with at least one second step. Each second step has a second grate tooth. The first grate tooth and the second grate tooth are arranged on the outer surface of the shaft. The teeth are staggered, and the first grate teeth and the second grate teeth do not contact; Among them, one or more ejection parts are provided between the first grate tooth and the second grate tooth farthest from the impeller, through which the fluid is ejected to the outside and recovered; The casing, the first step provided on the inner surface of the casing, and the first grate teeth on the first step are integrally formed. 2. The sealing device according to claim 1, wherein the first step and the second step have the same number of layers. 3. The sealing device according to claim 1, wherein the inner surface of the casing is coated with a coating at a position corresponding to the top of the second grate tooth. 4. The sealing device according to claim 3, wherein the material of the coating includes silver-copper alloy, NiCrAl and/or nickel graphite. 5. The sealing device according to claim 1, wherein the shape of each first grate tooth is the same and the shape of each second grate tooth is the same. 6. A sealing method, including: At least one layer of first steps is respectively provided on the inner surface of the casing, and each layer of first steps has a first grate tooth; At least one layer of second steps is provided on the outer surface of the shaft, and each layer of second steps has a second grate tooth; and The shaft is placed in the casing along the direction of the casing, the first grate teeth and the second grate teeth are staggered, and the first grate teeth and the second grate teeth do not contact; Wherein, one or more ejection parts are provided between the first grate tooth and the second grate tooth farthest from the impeller, through which the fluid is ejected to the outside and recovered; The casing, the first step provided on the inner surface of the casing, and the first grate teeth on the first step are integrally formed. 7. The sealing method according to claim 6, wherein the coating is applied on the inner surface of the casing at a position corresponding to the tip of the second grate tooth.