Mechanical seal for twin-screw compressor of heat pump unit

Abstract

The utility model provides a kind of mechanical seal for heat pump unit double screw compressor, including flange plate and flange sleeve, one end of flange sleeve is connected with one end of flange plate, the inside of flange plate near flange sleeve one end is equipped with static ring assembly, the inside of flange sleeve away from flange plate one end is equipped with dynamic ring assembly for being fixed in the outside of rotating shaft, the end of dynamic ring assembly and static ring assembly can be relatively rotated to form sealing surface along the circumference of the butt, the outside wall of the other end of dynamic ring assembly is equipped with lip seal between the inside wall of flange sleeve, lip seal, flange sleeve inner wall, dynamic ring seat outer wall and sealing surface outside wall form sealing cavity;Multiple flush inlet towards sealing surface and a flush outlet are set on the sidewall of flange sleeve, which are distributed along the circumference of the utility model discloses the mechanical seal for heat pump unit double screw compressor, improves installation efficiency by the form of unit portion preloading, and can realize flush scheme, prolongs the service life of sealing.

Description

Technical Field

[0001] This utility model relates to the field of mechanical seal technology, and more specifically, to a mechanical seal for a twin-screw compressor in a heat pump unit. Background Technology

[0002] A heat pump unit is a circulating system consisting of a compressor, heat exchanger, expansion valve, and receiver. The refrigerant circulates within the system under the action of the compressor. Inside the compressor, it undergoes a process of pressurization and heating from its gaseous state (up to 100°C). After entering the heat exchanger, it exchanges heat with the air, is cooled, and transforms into a liquid state. When it reaches the receiver, the liquid rapidly absorbs heat and evaporates, transforming back into a gaseous state, while its temperature drops to -20°C to -30°C. At this point, the surrounding air continuously transfers low-temperature heat to the refrigerant. This continuous circulation of the refrigerant achieves the conversion of low-temperature heat from the air into high-temperature heat, thus heating the chilled water.

[0003] This research primarily targets the mechanical seals used in the twin-screw compressors employed in the aforementioned units. Since the main refrigerant in these units is ammonia, and the twin-screw shaft is often a stepped shaft, the most common current design is a loose-assembly configuration. This involves installing the mechanical seal components one by one during compressor assembly at the user's site. This completely loose-assembly mechanical seal structure requires a long installation time and is prone to missing small parts, leading to a risk of unstable sealing performance later on. Furthermore, due to the unique structure of existing loose-assembly mechanical seals, flushing and cooling are difficult to achieve during use, resulting in insufficient cooling of the frictional heat of the sealing rings and affecting their service life. Summary of the Invention

[0004] To overcome at least one of the defects in the prior art, this utility model provides a mechanical seal for a twin-screw compressor of a heat pump unit. The pre-installation of modular components improves installation efficiency and enables a flushing solution, thus extending the seal's service life.

[0005] The technical solution adopted by this utility model is to provide a mechanical seal for a twin-screw compressor of a heat pump unit: including a flange and a flange sleeve, one end of the flange sleeve is axially connected to one end of the flange, the inner side of the flange near the end of the flange sleeve is provided with a first mounting groove, the first mounting groove is fitted with a stationary ring assembly that can slide axially, the inner side of the flange sleeve away from the flange is provided with a rotating ring assembly for fitting and fixing to the outside of a rotating shaft, the rotating ring assembly and one end of the stationary ring assembly are circumferentially rotatable to abut against each other to form a sealing surface, the outer side wall of the other end of the rotating ring assembly is fitted with a lip seal between the inner side wall of the flange sleeve, the lip seal, the inner wall of the flange sleeve, the outer wall of the rotating ring seat and the outer side wall of the sealing surface form a sealing cavity; the side wall of the flange sleeve is provided with a plurality of flushing inlets distributed circumferentially and facing the sealing surface, and the side wall of the flange sleeve near the lip seal is provided with a flushing outlet.

[0006] Compared with the prior art, the mechanical seal for a twin-screw compressor in a heat pump unit according to this utility model has the following advantages:

[0007] The mechanical seal structure for the twin-screw compressor of this utility model includes a pre-installed stationary ring assembly, which can be pre-assembled into a single unit before on-site installation and pre-fitted into the first mounting slot of the flange. That is, the stationary ring assembly and the flange are pre-assembled as a single unit. During on-site installation, the rotating ring is first installed onto the rotating ring seat, and then they are fitted together and fixed onto the rotating shaft. Next, the stationary ring assembly and the flange are installed into the compressor mounting cavity until the end face of the stationary ring assembly abuts against the end face of the rotating ring. The flange is then fixedly connected to the mounting cavity, which is very convenient. Furthermore, in this structure, the flange... One end is also connected to a flange sleeve. During installation, the flange sleeve extends into the cavity. A lip seal is fitted between the inner wall of the flange sleeve away from the flange and the outer wall of the moving ring seat. This forms a sealing cavity between the lip seal, the inner wall of the flange sleeve, the outer wall of the moving ring seat, and the outer wall of the sealing surface. Corresponding flushing inlets and outlets are opened on the side wall of the flange sleeve, realizing a flushing solution for the sealing surface. The flushing fluid can promptly flush away impurities and particles on the sealing surface, avoiding wear on the sealing surface. At the same time, it can also promptly remove the frictional heat of the sealing surface, preventing thermal deformation of the sealing ring, ensuring stable sealing performance, and extending service life.

[0008] As an improvement, the rotating ring assembly includes a rotating ring seat and a rotating ring. One end of the rotating ring seat has a second mounting groove, and one end of the rotating ring is axially inserted into the second mounting groove. Multiple set screws are provided on the side wall of the middle portion of the rotating ring seat for a transmission connection with the outer wall of the rotating shaft. In this improved structure, the rotating ring seat achieves a transmission connection with the rotating shaft through set screws, resulting in a simple structure, stable drive, and convenient assembly and disassembly.

[0009] In a further improvement, a mounting step is provided on the outer peripheral wall of the other end of the moving ring seat. The lip seal is fitted onto the mounting step, and a retaining ring for axially limiting the lip seal is fitted on the outer end face of the mounting step. In the above improved structure, the connection and fixation between the lip seal and the moving ring seat are achieved through the mounting step and retaining ring structure. The structure is simple, easy to install, and provides stable limiting.

[0010] In a further improvement, a wear-resistant coating is provided on the inner circumferential wall of the flange sleeve at the position where it mates with the radial outer circumferential wall of the lip seal. In the above improved structure, the wear-resistant coating increases the hardness of the inner wall of the flange sleeve, improves its wear resistance, and prevents leakage caused by wear during continuous friction with the lip seal.

[0011] In a further improvement, the stationary ring assembly includes a stationary ring seat and a stationary ring. One end of the stationary ring seat has a third mounting groove, and one end of the stationary ring is fitted into the third mounting groove. The other end of the stationary ring has a positioning step, and an elastic compensation element is provided between the axial end face of the positioning step and the end face of the flange, so that the stationary ring assembly always tends to move towards the moving ring end. In the above improved structure, the elastic compensation element is located at the stationary ring end, and the compensation element remains stationary, avoiding the defect of the compensation ring not following the target position at high linear velocities and ensuring stable compensation performance.

[0012] In a further improvement, the elastic compensation component includes multiple springs. Multiple circumferentially distributed spring holes are formed on the end face of the flange. One end of each spring is fitted and positioned within its corresponding spring hole, and the other end of each spring abuts against the axial end face of the positioning step. In this improved structure, friction compensation of the stationary ring is achieved through multiple small springs, resulting in a stable and reliable compensation force.

[0013] In a further improvement, a sealing step is provided on the outer wall of the portion of the stationary ring seat that is fitted into the first mounting groove. A sealing ring is provided between the radial outer wall of the sealing step and the inner wall of the first mounting groove. A gasket is also fitted at the bottom of the first mounting groove, and the inner wall of the gasket slides in contact with the radial outer wall of the sealing step. In the above improved structure, the sealing step and sealing ring achieve dynamic sealing between the stationary ring seat and the flange, and the sealing ring is positioned by the PTFE gasket, ensuring stable sealing performance.

[0014] In a further improvement, a liquid collection tank is provided at one end of the flange near the stationary ring seat and at the bottom of the first mounting groove. An axially extending channel is provided between the inner wall of the stationary ring and stationary ring seat and the outer wall of the rotating shaft, leading to the liquid collection tank. A radially distributed leakage collection channel is provided on the side wall of the flange, connecting to the liquid collection tank. In this improved structure, the liquid collection tank can collect minor leaks, preventing leaked liquid from directly exposing to the atmosphere.

[0015] In a further improvement, the inner hole of the stationary ring seat at the end away from the stationary ring is a tapered hole, and the end of the tapered hole near the liquid collection tank is the larger diameter end. In the above improved structure, the tapered hole at the end of the inner hole of the stationary ring seat near the liquid collection tank allows the leaking liquid to flow and collect more effectively into the liquid collection tank when the main seal leaks, and then be collected through the collection channel.

[0016] In a further improvement, a throttling groove is formed on the inner wall of the flange at the end away from the stationary ring seat. In the above improved structure, the throttling groove can further prevent the leaked liquid in the collection tank from being thrown out, thus better ensuring the sealing performance of the entire sealing structure.

[0017] The aforementioned improvements and advantages of this invention will be set forth in detail in the following specific embodiments, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained through the structures particularly pointed out in the description and drawings. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the mechanical seal for the twin-screw compressor of the heat pump unit according to this utility model;

[0019] Figure 2 for Figure 1 Enlarged structural diagram at point A in the diagram;

[0020] Figure 3 for Figure 1 Enlarged structural diagram at point B in the image.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Flange; 2. Flange sleeve; 3. First mounting groove; 4. Rotating ring seat; 5. Rotating ring; 6. Lip seal; 7. Sealing cavity; 8. Flushing inlet; 9. Flushing outlet; 10. Mounting step; 11. Snap ring; 12. Wear-resistant coating; 13. Second mounting groove; 14. Set screw; 15. Stationary ring seat; 16. Stationary ring; 17. Third mounting groove; 18. Positioning step; 19. Spring; 20. Sealing step; 21. Sealing ring; 22. Gasket; 23. Liquid collection tank; 24. Leakage collection channel; 25. Throttling groove; 26. Connecting hole; Detailed Implementation

[0023] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0024] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0025] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] See Figures 1-3 As shown in the embodiment of this application, a mechanical seal for a twin-screw compressor of a heat pump unit is disclosed, including a flange 1 and a flange sleeve 2 fitted outside the rotating shaft. One end of the flange sleeve 2 is axially connected to one end of the flange 1. Specifically, an annular positioning groove is provided at one end of the flange 1, and one end of the flange sleeve 2 is axially inserted into the positioning groove. A corresponding sealing element is provided between the end face of the flange sleeve 2 and the bottom of the positioning groove. In addition, a plurality of circumferentially distributed connecting bolts are provided at the other end of the flange 1, and each connecting bolt is respectively connected to the end of the flange sleeve 2.

[0027] A first mounting groove 3 is provided on the inner side of the flange 1 near the flange sleeve 2. A stationary ring assembly that can slide axially is installed in the first mounting groove 3. A rotating ring assembly for mounting and fixing to the outside of the rotating shaft is provided on the inner side of the flange sleeve 2 away from the flange 1. One end of the rotating ring assembly and one end of the stationary ring assembly can rotate relative to each other in the circumferential direction to form a sealing surface. A lip seal 6 is installed between the outer wall of the other end of the rotating ring seat assembly and the inner wall of the flange sleeve 2. A sealing cavity 7 is formed between the lip seal 6, the inner wall of the flange sleeve 2, the outer wall of the rotating ring seat 4, and the outer wall of the sealing surface. Multiple flushing inlets 8 are provided on the side wall of the flange sleeve 2, which are distributed circumferentially and face the sealing surface. A flushing outlet 9 is provided on the side wall of the flange sleeve 2 near the lip seal 6. Both the flushing inlets 8 and the flushing outlet 9 are connected to the sealing cavity 7 to realize the circulation of flushing fluid for flushing and cooling the sealing surface.

[0028] In the above structure, the stationary ring is set as a pre-installed component, the rotating ring component is pre-installed on the rotating shaft, the stationary ring is pre-installed with the flange 1, and then the pre-installed stationary ring and flange 1 are installed into the compressor mounting cavity. The flange 1 is fixed to the cavity to ensure that the sealing rings of the stationary ring and the rotating ring are in contact. The whole installation process is simple and quick.

[0029] In this embodiment, the flushing outlet 9 is preferably located at the top of the flange sleeve 2. The multi-point flushing inlet 8 and the flushing outlet 9 in a special position ensure the lubrication of the mechanical seal liquid film; at the same time, it can quickly reduce the heat on the mechanical seal surface and extend the service life of the mechanical seal.

[0030] In this embodiment, see Appendix Figure 2 Specifically, the rotating ring assembly includes a rotating ring seat 4 and a rotating ring 5. The inner side of one end of the rotating ring seat 4 is provided with a stepped second mounting groove 13. One end of the rotating ring 5 is inserted into the second mounting groove 13 along the axial direction, and a corresponding seal is also provided between the rotating ring 5 and the second mounting groove 13.

[0031] Multiple circumferentially distributed set screws 14 are installed on the side wall of the middle part of the moving ring seat 4. When the moving ring seat 4 is fitted onto the fixed step part of the rotating shaft, the transmission connection between the moving ring seat 4 and the rotating shaft is achieved by tightening the multiple set screws 14, that is, the moving ring seat 4 rotates synchronously with the rotating shaft. In addition, a mounting step 10 is provided on the outer peripheral wall of the moving ring seat 4 away from the moving ring 5. The lip seal 6 is fitted onto the mounting step 10, and a retaining spring 11 for axially limiting the lip seal 6 is fitted on the outer end face of the mounting step 10.

[0032] On the other hand, see Appendix Figure 2 The radial outer peripheral wall of the lip seal 6 is in sealing fit with the inner wall of the flange sleeve 2, and a wear-resistant coating 12 is provided on the inner peripheral wall of the flange sleeve 2 at the position where it mates with the radial outer peripheral wall of the lip seal 6. Preferably, the wear-resistant coating 12 is a chromium oxide plating.

[0033] In this embodiment, the stationary ring assembly includes a stationary ring seat 15 and a stationary ring 16. One end of the stationary ring seat 15 is provided with a third mounting groove 17. One end of the stationary ring 16 is slidably fitted into the third mounting groove 17 along the axial direction. Sealing elements are provided between the tail end of the stationary ring 16 and the bottom of the third mounting groove 17, and between the radial outer side wall of the stationary ring 16 near the rotating ring 5 and the side wall of the third mounting groove 17. At least one anti-rotation pin extending along the axial direction is connected to the end face of the flange 1. An anti-rotation pin groove corresponding to the anti-rotation pin is provided on the outer peripheral wall of the stationary ring seat 15 to ensure the stability of the fitting structure between the stationary ring seat 15 and the flange 1.

[0034] More specifically, in the above structure, multiple connecting holes 26 are provided on the side wall of the stationary ring seat 15 near the bottom of the third mounting groove 17, which are connected to the third mounting groove 17. The flushing fluid in the sealing cavity 7 can contact the stationary ring 16 in the third mounting groove 17 through the multiple connecting holes 26, further improving the cooling effect of the stationary ring 16, avoiding excessive sealing friction temperature that could cause thermal cracking of the stationary ring 16 or deformation of the flatness of the sealing surface, and ensuring stable sealing performance.

[0035] The other end of the stationary ring 16 is provided with a positioning step 18. An elastic compensation element is provided between the axial end face of the positioning step 18 and the end face of the flange 1 so that the stationary ring assembly always tends to move towards the end of the moving ring 5. Preferably, the elastic compensation element includes a plurality of springs 19. The springs 19 here are small cylindrical springs 19. A plurality of spring holes 19 are opened on the end face of the flange 1 along the circumference. One end of each spring 19 is respectively fitted and positioned in the corresponding spring hole 19, and the other end of each spring 19 abuts against the axial end face of the positioning step 18.

[0036] In some other embodiments, if the axial dimension of the stationary ring seat 15 is sufficient, the spring 19 hole can also be provided on the axial end face of the positioning step 18; the spring 19 hole can also be provided on both the axial end face of the positioning step 18 and the end face of the flange 1, so that both ends of each spring 19 have stable limitation.

[0037] Additionally, a sealing step 20 is provided on the outer wall of the portion of the stationary ring seat 15 that is fitted into the inner part of the first mounting groove 3. A sealing ring 21 is provided between the radial outer wall of the sealing step 20 and the inner wall of the first mounting groove 3. A gasket 22 is also fitted at the bottom of the first mounting groove 3, and the inner wall of the gasket 22 slides in fit with the radial outer wall of the sealing step 20. Preferably, the gasket 22 is a polytetrafluoroethylene gasket 22. Polytetrafluoroethylene has excellent chemical stability, corrosion resistance, sealing performance, high lubricity and non-stickiness, electrical insulation and good anti-aging resistance.

[0038] In this embodiment, see Appendix Figure 1 and 3 A liquid collection tank 23 is provided at one end of the flange 1 near the stationary ring seat 15 and at the bottom of the first mounting groove 3. A channel extending axially to the liquid collection tank 23 is provided between the inner wall of the stationary ring 16 and the stationary ring seat 15 and the outer wall of the rotating shaft. A leakage collection channel 24, radially distributed and connected to the liquid collection tank 23, is provided on the side wall of the flange 1. When a slight leak occurs at the sealing surface, the leaking liquid can enter the liquid collection tank 23 along the channel and be collected uniformly through the collection channel, preventing the leaking liquid from directly overflowing to the atmosphere along the outer side of the rotating shaft. Therefore, it is not necessary to replace the seal immediately, thus extending its service life to a certain extent. In the above structure, the inner hole of the stationary ring seat 15 away from the stationary ring 16 is a tapered hole, and the end of the tapered hole near the liquid collection tank 23 is the larger diameter end. The tapered hole structure allows the leaking liquid to flow into the liquid collection tank 23 more quickly, facilitating collection.

[0039] More specifically, a throttling groove 25 is provided on the inner wall of the flange 1 at the end away from the stationary ring seat 15. This prevents the leaking liquid in the collection tank 23 from being thrown out, thus better ensuring the sealing performance of the entire sealing structure.

[0040] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A mechanical seal for a twin-screw compressor in a heat pump unit, characterized in that: The assembly includes a flange (1) and a flange sleeve (2). One end of the flange sleeve (2) is axially connected to one end of the flange (1). The flange (1) has a first mounting groove (3) on its inner side near the end of the flange sleeve (2). A stationary ring assembly that can slide axially is fitted in the first mounting groove (3). The flange sleeve (2) has a moving ring assembly inside its inner side away from the flange (1) for mounting and fixing to the outside of a rotating shaft. One end of the moving ring assembly and the stationary ring assembly are circumferentially connected. The two parts are rotatably abutted to form a sealing surface. A lip seal (6) is fitted between the outer wall of the other end of the moving ring assembly and the inner wall of the flange sleeve (2). A sealing cavity (7) is formed between the lip seal (6), the inner wall of the flange sleeve (2), the outer wall of the moving ring seat (4), and the outer wall of the sealing surface. A plurality of flushing inlets (8) are provided on the side wall of the flange sleeve (2) and are distributed circumferentially and facing the sealing surface. A flushing outlet (9) is provided on the side wall of the flange sleeve (2) near the lip seal (6).

2. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 1, characterized in that: The moving ring assembly includes a moving ring seat (4) and a moving ring (5). One end of the moving ring seat (4) is provided with a second mounting groove (13), and one end of the moving ring (5) is inserted into the second mounting groove (13) along the axial direction. A plurality of set screws (14) for drivingly connecting the moving ring seat (4) to the outer wall of the rotating shaft are provided on the side wall in the middle.

3. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 2, characterized in that: The outer peripheral wall of the other end of the moving ring seat (4) is provided with an installation step (10), the lip seal (6) is fitted on the installation step (10), and a retaining ring (11) for axially limiting the lip seal (6) is fitted on the outer end face of the installation step (10).

4. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 1, characterized in that: The flange sleeve (2) has a wear-resistant coating (12) at the position where it mates with the radial outer peripheral wall of the lip seal (6).

5. The mechanical seal for a twin-screw compressor of a heat pump unit according to any one of claims 1 to 4, characterized in that: The stationary ring assembly includes a stationary ring seat (15) and a stationary ring (16). One end of the stationary ring seat (15) is provided with a third mounting groove (17), and one end of the stationary ring (16) is fitted into the third mounting groove (17). The other end of the stationary ring (16) is provided with a positioning step (18). An elastic compensation element is provided between the axial end face of the positioning step (18) and the end face of the flange (1) so that the stationary ring assembly always has a tendency to move towards one end of the moving ring (5).

6. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 5, characterized in that: The elastic compensation component includes multiple springs (19). Multiple spring (19) holes distributed circumferentially are provided on the end face of the flange (1). One end of each spring (19) is respectively fitted and positioned in the corresponding spring (19) hole, and the other end of each spring (19) abuts against the axial end face of the positioning step (18).

7. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 5, characterized in that: The stationary ring seat (15) is fitted with a sealing step (20) on the outer wall of the inner part of the first mounting groove (3). A sealing ring (21) is provided between the radial outer wall of the sealing step (20) and the inner wall of the first mounting groove (3). A gasket (22) is also fitted at the bottom of the first mounting groove (3), and the inner wall of the gasket (22) slides in cooperation with the radial outer wall of the sealing step (20).

8. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 5, characterized in that: A liquid collection tank (23) is provided at one end of the flange (1) near the stationary ring seat (15) and at the bottom of the first mounting groove (3). A channel extending axially to the liquid collection tank (23) is provided between the inner wall of the stationary ring (16) and the stationary ring seat (15) and the outer wall of the rotating shaft. A leakage collection channel (24) is provided on the side wall of the flange (1) and is radially distributed and connected to the liquid collection tank (23).

9. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 8, characterized in that: The inner hole of the stationary ring seat (15) away from the stationary ring (16) is a tapered hole, and the end of the tapered hole near the liquid collection tank (23) is the large diameter end.

10. The mechanical seal for a twin-screw compressor in a heat pump unit according to claim 8, characterized in that: A throttling groove (25) is provided on the inner wall of the flange (1) at the end away from the stationary ring seat (15).

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