CN115030913A

CN115030913A - Magnetic fluid sealing device for large-shaft-diameter centrifugal compressor

Info

Publication number: CN115030913A
Application number: CN202210561907.XA
Authority: CN
Inventors: 朱维兵; 吴朝军; 王和顺; 颜招强; 晏静江
Original assignee: Zigong Zhaoqiang Sealing Product Industry Co ltd; Xihua University
Current assignee: Zigong Zhaoqiang Sealing Product Industry Co ltd; Xihua University
Priority date: 2022-05-23
Filing date: 2022-05-23
Publication date: 2022-09-09

Abstract

The invention discloses a magnetic fluid sealing device for a large-shaft-diameter centrifugal compressor, which comprises a centrifugal compressor shell, wherein a shaft sleeve is arranged in the centrifugal compressor shell; a sealing seat, a magnetic fluid sealing mechanism, a bearing end cover and a labyrinth sealing ring are sequentially arranged between the centrifugal compressor shell and the shaft sleeve from left to right, and the labyrinth sealing ring is arranged close to the outer wall of the shaft sleeve; the magnetic fluid sealing mechanism is arranged close to the outer wall of the shaft sleeve, a cooling mechanism is detachably connected between the upper part of the magnetic fluid sealing mechanism and the shell of the centrifugal compressor, and the cooling mechanism is communicated with a channel for the inlet and outlet of cooling liquid. The sealing device provided by the invention is sequentially provided with the labyrinth sealing ring, the magnetic fluid sealing mechanism, the cooling jacket and the sealing seat along the medium leakage direction, so that zero leakage is realized, high rotating speed can be borne, real-time cooling of the magnetic fluid sealing device can be realized, frictional heating is reduced, the impact pressure of a high-pressure medium can be effectively reduced, the service life of each sealing part is prolonged, and the service life of the whole device is prolonged.

Description

Magnetic fluid sealing device for large-shaft-diameter centrifugal compressor

Technical Field

The invention relates to the technical field of magnetic fluid sealing, in particular to a magnetic fluid sealing device for a large-shaft-diameter centrifugal compressor.

Background

With the increasing scale of the treatment of single set of devices in the fields of petroleum, chemical industry, coal chemical industry and the like, the upsizing of a corresponding centrifugal compressor becomes a necessary trend, wherein the most representative is an ethylene three-machine (an ethylene compressor, a propylene compressor and a pyrolysis gas compressor) with the production scale of 80 ten thousand tons/year; product gas, propylene, ethylene compressors for large MTO units; the diameter of a compressor impeller of a mixed refrigerant compressor of a large LNG project (more than 500 ten thousand square/day) reaches more than 1300mm, the shaft diameter basically exceeds 260mm, and the maximum diameter reaches 350 mm; olefin compressors, propylene compressors of large MTP devices; a propylene compressor in the coal-to-gas purification device; a recycle hydrogen compressor of a large reformer; fluorine gas compressors for large-scale catalytic devices, and the like. It is seen that a large-scale centrifugal compressor plays more and more important roles in various fields, but the shaft diameter of the main shaft is too large, so that the requirements on sealing materials, design, manufacture and experiments are extremely high, and the shaft end sealing of the main shaft is a very troublesome problem all the time. Labyrinth seal, floating ring seal, mechanical seal and dry gas seal in the existing sealing mode are all used for sealing a rotary main shaft of a large-shaft-diameter centrifugal compressor, but all have certain defects: although the labyrinth seal has simple structure, less auxiliary equipment and long service life, the leakage amount is large; the floating ring has high sealing reliability and good centering performance, but has serious internal leakage, thereby increasing the complexity of equipment; mechanical seal and dry gas seal are similar, leak the leakage quantity low, the operation stability is high, but when being used for the big shaft diameter centrifugal compressor seal, its sound ring size is too big and leads to the processing difficulty, and dry gas seal still needs complicated auxiliary system simultaneously, and the price is expensive. The magnetic fluid seal is a novel sealing mode, has been widely applied to various fields by virtue of the characteristics of zero leakage, long service life, high reliability, no pollution, high bearing speed, low viscous friction and the like, and provides a solution for the problem of difficult sealing of a large-shaft-diameter centrifugal compressor since the past. Therefore, in order to solve the problem that the existing sealing mode is difficult to solve the sealing difficulty caused by the high linear speed of the rotating main shaft of the large-shaft-diameter centrifugal compressor, a novel magnetic fluid sealing device for the large-shaft-diameter centrifugal compressor with the cooling and pressure reducing functions is urgently needed.

Disclosure of Invention

The invention aims to provide a magnetic fluid sealing device for a large-shaft-diameter centrifugal compressor, which is used for solving the problems in the prior art.

In order to achieve the purpose, the invention provides the following scheme: the invention provides a magnetic fluid sealing device for a large-shaft-diameter centrifugal compressor, which comprises a centrifugal compressor shell, wherein a shaft sleeve is arranged in the centrifugal compressor shell; a sealing seat, a magnetic fluid sealing mechanism, a bearing end cover and a labyrinth sealing ring are sequentially arranged between the centrifugal compressor shell and the shaft sleeve from left to right, and the labyrinth sealing ring is arranged close to the outer wall of the shaft sleeve; the magnetic fluid sealing mechanism is arranged close to the outer wall of the shaft sleeve, a cooling mechanism is detachably connected between the upper part of the magnetic fluid sealing mechanism and the shell of the centrifugal compressor, and the cooling mechanism is communicated with a channel for the inlet and outlet of cooling liquid.

Preferably, the magnetic fluid sealing mechanism comprises a non-magnetic conductive shell and a magnetic fluid, magnetic isolation cushion pads are fixedly arranged at two end parts of the inner side of the non-magnetic conductive shell, a plurality of groups of permanent magnets are arranged between two groups of the magnetic isolation cushion pads, and end pole shoes are fixedly arranged between each group of the permanent magnets at the outermost side and each group of the magnetic isolation cushion pads; a middle pole shoe is fixedly arranged between every two adjacent groups of permanent magnets; the bottom of the non-magnetic conduction shell is provided with a plurality of groups of pole teeth, and the gaps between the adjacent pole teeth and the gaps between the middle pole shoes are filled with fillers.

Preferably, the filler is modified polytetrafluoroethylene.

Preferably, the cooling mechanism comprises a cooling jacket outer shell and a cooling jacket inner shell, an accommodating cavity for storing cooling liquid is arranged between the cooling jacket outer shell and the cooling jacket inner shell, and the accommodating cavity is communicated with the channel.

Preferably, the channels are provided in two groups, and the two groups of channels are symmetrically arranged around the cooling jacket shell and penetrate through the cooling jacket shell; and the two groups of channels penetrate through the shell of the centrifugal compressor and are communicated with the outside.

Preferably, two groups of bearings are arranged on the outer sides of two end parts of the non-magnetic conduction shell, the two groups of bearings are sleeved on the outer wall of the shaft sleeve, and the two groups of bearings are in contact with the cooling jacket shell; one group of the bearing is abutted to the sealing seat, the other group of the bearing is abutted to the bearing end cover, and the two groups of the bearings are provided with bearing clamping rings outside.

Preferably, the bottom of the labyrinth seal ring is abutted to the outer wall of the shaft sleeve, and one side wall of the labyrinth seal ring is detachably connected with the bearing end cover.

Preferably, the sealing seat is provided with a stainless steel rubber sealing ring for positioning and pressing the bearing.

Preferably, the seal holder and the centrifugal compressor housing are connected by a third screw; the sealing seat is connected with the cooling jacket shell through a second screw; the bearing end cover is connected with the cooling jacket shell through a fourth screw; and the labyrinth seal ring is connected with the bearing end cover through a fifth screw.

The invention discloses the following technical effects: the sealing device is provided with the labyrinth sealing ring, the magnetic fluid sealing mechanism, the cooling jacket and the sealing seat in sequence along the medium leakage direction, and all the components are arranged between the shaft sleeve and the centrifugal compressor shell, so that zero leakage is realized, high rotating speed can be borne, the magnetic fluid sealing device can be cooled in real time, friction heating is reduced, impact pressure of a high-pressure medium can be effectively reduced, the service life of each sealing component is prolonged, and the service life of the whole device is prolonged.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

FIG. 1 is a schematic structural diagram of a magnetic fluid sealing device according to a first embodiment;

FIG. 2 is an enlarged view of a portion of FIG. 1;

FIG. 3 is an enlarged view of a portion B of FIG. 1;

FIG. 4 is a partial enlarged view of C in FIG. 1;

FIG. 5 is an enlarged view of a portion D of FIG. 1;

FIG. 6 is a schematic structural diagram of the second embodiment.

Wherein: 1. a shaft sleeve; 2. a first screw; 3. a stainless steel rubber seal ring; 4. a bearing collar; 5. a bearing; 6. a first O-ring seal; 7. a second screw; 8. a third screw; 9. A gasket; 10. a second O-ring seal; 11. a centrifugal compressor housing; 12. a fourth screw; 13. a cooling jacket housing; 14. a third O-ring seal; 15. a fifth screw; 16. a fourth O-shaped sealing ring; 17. a labyrinth seal ring; 18. a fifth O-shaped seal ring; 19. a sixth O-ring seal; 20. a bearing end cap; 21. a magnetic isolation buffer pad; 22. an end pole piece; 23. a permanent magnet; 24. an intermediate pole shoe; 25. a seventh O-ring seal; 26. a cooling jacket inner shell; 27. a sealing seat; 28. a magnetic fluid; 29. and (4) filling.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description thereof.

The first embodiment is as follows:

referring to fig. 1-5, the invention provides a magnetic fluid sealing device for a large-shaft-diameter centrifugal compressor, which comprises a centrifugal compressor shell 11, wherein a shaft sleeve 1 is arranged in the centrifugal compressor shell 11; the shaft sleeve 1 is used for forming a magnetic circuit, all parts on the shaft sleeve 1 are installed and positioned, the shaft sleeve 1 is fixed on a rotating shaft through first screws 2, and the first screws 2 are hexagon socket head cap end fastening screws; a sealing seat 27, a magnetic fluid sealing mechanism, a bearing end cover 20 and a labyrinth sealing ring 17 are sequentially arranged between the centrifugal compressor shell 11 and the shaft sleeve 1 from left to right, and the labyrinth sealing ring 17 is tightly abutted to the outer wall of the shaft sleeve 1; the magnetic fluid 28 sealing mechanism is arranged close to the outer wall of the shaft sleeve 1, a cooling mechanism is detachably connected between the upper part of the magnetic fluid sealing mechanism and the shell 11 of the centrifugal compressor, and the cooling mechanism is communicated with a channel for the inlet and the outlet of cooling liquid.

The magnetic fluid sealing mechanism comprises a non-magnetic conduction shell, magnetic isolation buffer pads 21 are fixedly arranged at two end parts of the inner side of the non-magnetic conduction shell, magnetic leakage of a magnetic fluid structure part can be reduced, vibration of the magnetic fluid sealing device and pole shoe collision are prevented, rectangular teeth are machined on an inner ring, and the magnetic fluid sealing mechanism also has a pressure reduction effect; a plurality of groups of permanent magnets 23 are arranged between the two groups of magnetism isolating buffer cushions 21, and end pole shoes 22 are fixedly arranged between each group of permanent magnets 23 on the outermost side and each group of magnetism isolating buffer cushions 21; a middle pole shoe 24 is fixedly arranged between every two adjacent groups of permanent magnets 23, and the end pole shoes 22 and the middle pole shoes 24 are used for forming a magnetic circuit; a plurality of groups of pole teeth are arranged at the bottom of the non-magnetic conductive shell, and the gaps between adjacent pole teeth and the gap between the middle pole shoes 24 are filled with fillers 29; the magnetic fluid 28 seal mainly comprises a permanent magnet 23, pole shoes (the middle pole shoe 24 and the end pole shoe 22 are collectively called as pole shoes), a magnetic fluid 28, a non-magnetic shell and a magnetic conduction rotating shaft (shaft sleeve 1), and is used for forming a liquid sealing ring under the action of a seal gap magnetic field gradient to play a role in sealing.

The filler 29 is modified polytetrafluoroethylene; the filler 29 is filled in the gaps between the teeth and the gaps between the pole shoes, so that the influence of centrifugal force caused by high rotating speed can be reduced.

The cooling mechanism comprises a cooling jacket outer shell 13 and a cooling jacket inner shell 26, an accommodating cavity for storing cooling liquid is arranged between the cooling jacket outer shell 13 and the cooling jacket inner shell 26, and the accommodating cavity is communicated with the channel; the cooling jacket outer shell 13 and the cooling jacket inner shell 26 form a cooling jacket for protecting and connecting the device, and cooling liquid is introduced into the inner cooling flow channel to reduce the friction shear heat of the magnetic fluid 28.

The two groups of channels are symmetrically arranged about the cooling jacket shell 13 and penetrate through the cooling jacket shell 13; both sets of passages extend through the centrifugal compressor housing 11 and communicate with the outside.

Two groups of bearings 5 are arranged on the outer sides of two end parts of the non-magnetic conductive shell, the two groups of bearings 5 are deep groove ball bearings 5, the bearings 5 are used for fixing the magnetic fluid sealing mechanism, the sealing gap between the pole teeth and the shaft sleeve 1 is ensured, and the pole teeth structure is prevented from being damaged by jumping of the shaft sleeve 1; two groups of bearings 5 are sleeved on the outer wall of the shaft sleeve 1, and the two groups of bearings 5 are in contact with the cooling jacket shell 13; one group of bearings 5 is abutted with the sealing seat 27, the other group of bearings 5 is abutted with the bearing end cover 20, and the bearing end cover 20 is used for pressing and positioning the bearings 5 and connecting the labyrinth sealing ring 17; and bearing clamping rings 4 are arranged outside the two groups of bearings 5, and the bearing clamping rings 4 are used for fixing and clamping the bearings 5.

The bottom of the labyrinth seal ring 17 is abutted against the outer wall of the shaft sleeve 1, and one side wall of the labyrinth seal ring 17 is detachably connected with the bearing end cover 20; the labyrinth seal ring 17 is used for reducing the pressure of a sealing medium and preventing the sealing medium from being suddenly communicated to break the magnetic fluid seal ring, so that the sealing is failed.

The sealing seat 27 is provided with a stainless steel rubber sealing ring 3 for positioning the compression bearing 5; the stainless steel rubber sealing ring 3 plays a role in auxiliary sealing, and the sealing failure of the whole device is prevented when the magnetic fluid sealing structure fails.

The seal holder 27 and the centrifugal compressor housing 11 are connected by a third screw 8; the sealing seat 27 is connected with the cooling jacket shell 13 through a second screw 7; the bearing end cover 20 is connected with the cooling jacket shell 13 through a fourth screw 12; the labyrinth seal ring 17 is connected with the bearing end cover 20 through a fifth screw 15; the second screw 7, the fourth screw 12 and the fifth screw 15 are all hexagon socket head cap screws; third screw 8 is hexagonal head screw, and third screw 8 is connected with gasket 9, and third screw 8 cover is equipped with gasket 9, and gasket 9 can increase screw area of contact, reduces pressure, prevents not hard up, protection part and screw.

A first O-shaped sealing ring 6 is arranged between the cooling jacket shell 13 and the sealing seat 27; a second O-shaped sealing ring 10 is arranged between the sealing seat 27 and the centrifugal compressor shell 11, and a third O-shaped sealing ring 14 is arranged between the end cover of the bearing 5 and the cooling jacket shell 13; a fourth O-shaped sealing ring 16 is arranged between the labyrinth sealing ring 17 and the end cover of the bearing 5; a fifth O-shaped sealing ring 18 and a sixth O-shaped sealing ring 19 are arranged between the shaft sleeve 1 and the rotating shaft; a seventh O-ring 25 is disposed between the non-magnetically conductive housing and the cooling jacket housing 13; the sealing ring plays a role in auxiliary sealing.

The working process is as follows: when the high-pressure medium flows along the leakage direction, the high-pressure medium firstly passes through the labyrinth sealing ring 17, and the labyrinth sealing ring 17 has a pressure reduction function so as to prevent the magnetic fluid sealing ring from being broken when the high-pressure medium is suddenly introduced; similarly, the magnetic isolation buffer cushions 21 at the left end and the right end of the magnetic fluid sealing structure are also processed into a labyrinth sealing tooth-shaped structure, so that the same pressure reduction effect is exerted, and the pressure resistance of the sealing device is improved; in order to prevent the magnetic fluid from sealing failure after sealing failure, a stainless steel rubber sealing ring 3 which can be used for high linear velocity is arranged at the sealing seat 27 as a final sealing guarantee. Because the rotating shaft has higher linear speed, shearing friction heating of the magnetic fluid 28 is more serious, the sealing performance is reduced, and forced convection cooling treatment is carried out on the magnetic fluid 28 sealing device by designing a cooling jacket, so that the influence of friction heat is reduced; the centrifugal force influence brought by high-speed rotation can also reduce the sealing performance, and the influence of the centrifugal force can be effectively reduced by filling the high-temperature-resistant material of modified Polytetrafluoroethylene (PTFE) between the pole teeth and the pole shoes. By utilizing the response characteristic of the magnetic fluid 28 to the magnetic field, under the action of a magnetic loop formed among the high-performance permanent magnet 23, the end pole shoe 22, the middle pole shoe 24 and the shaft sleeve 1, the magnetic fluid 28 injected into the gap among the shaft sleeve 1, the end pole shoe and the middle pole shoe is firmly adsorbed below the pole teeth to form a plurality of liquid O-shaped sealing rings, so that the gap is completely blocked, and the sealing purpose is achieved.

Example two: referring to fig. 6, the present embodiment is different from the first embodiment only in that the present embodiment is provided with a medium return pipe, the direction of the medium return pipe and the direction of the medium leakage are perpendicular to the medium return pipe, the medium return pipe sequentially penetrates through the end cover of the bearing 5 and the centrifugal compressor housing 11 and is communicated with the outside, and one end of the medium return pipe located outside is a medium return port for realizing medium return.

In the description of the present invention, it is to be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the present invention.

The above-mentioned embodiments are only for describing the preferred mode of the present invention, and do not limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A magnetic fluid sealing device for a large-shaft-diameter centrifugal compressor is characterized in that: the centrifugal compressor comprises a centrifugal compressor shell (11), wherein a shaft sleeve (1) is arranged in the centrifugal compressor shell (11); a sealing seat (27), a magnetic fluid sealing mechanism, a bearing end cover (20) and a labyrinth sealing ring (17) are sequentially arranged between the centrifugal compressor shell (11) and the shaft sleeve (1) from left to right, and the labyrinth sealing ring (17) is tightly arranged against the outer wall of the shaft sleeve (1); the magnetic fluid sealing mechanism is arranged close to the outer wall of the shaft sleeve (1), a cooling mechanism is detachably connected between the upper part of the magnetic fluid sealing mechanism and the shell (11) of the centrifugal compressor, and the cooling mechanism is communicated with a channel for the inlet and outlet of cooling liquid.

2. A magnetic fluid seal arrangement for a large shaft diameter centrifugal compressor according to claim 1 wherein: the magnetic fluid sealing mechanism comprises a non-magnetic conductive shell and a magnetic fluid (28), two end parts of the inner side of the non-magnetic conductive shell are fixedly provided with magnetic isolation cushion pads (21), a plurality of permanent magnets (23) are arranged between two groups of magnetic isolation cushion pads (21), and end pole shoes (22) are fixedly arranged between two permanent magnets (23) positioned on the outermost side and each adjacent magnetic isolation cushion pad (21); a middle pole shoe (24) is fixedly arranged between every two adjacent groups of permanent magnets (23); the bottom of the non-magnetic conduction shell is provided with a plurality of groups of pole teeth, and the gaps between adjacent pole teeth and the gaps between the middle pole shoes (24) are filled with fillers (29).

3. The magnetic fluid seal device for a large shaft diameter centrifugal compressor according to claim 2, wherein: the filler (29) is modified polytetrafluoroethylene.

4. A magnetic fluid seal arrangement for a large shaft diameter centrifugal compressor according to claim 3 wherein: the cooling mechanism comprises a cooling jacket outer shell (13) and a cooling jacket inner shell (26), an accommodating cavity for storing cooling liquid is arranged between the cooling jacket outer shell (13) and the cooling jacket inner shell (26), and the accommodating cavity is communicated with the channel.

5. A magnetic fluid seal arrangement for a large shaft diameter centrifugal compressor according to claim 4 wherein: the channels are arranged in two groups, and the two groups of channels are symmetrically arranged relative to the cooling jacket shell (13) and penetrate through the cooling jacket shell (13); and the two groups of channels penetrate through the shell (11) of the centrifugal compressor and are communicated with the outside.

6. A magnetic fluid seal arrangement for a large shaft diameter centrifugal compressor according to claim 5 wherein: two groups of bearings (5) are arranged on the outer sides of two end parts of the non-magnetic conduction shell, the two groups of bearings (5) are sleeved on the outer wall of the shaft sleeve (1), and the two groups of bearings (5) are in contact with the cooling jacket shell (13); one set of bearing (5) and seal receptacle (27) butt, another group bearing (5) and bearing end cover (20) butt, two sets of bearing (5) outside all is provided with bearing rand (4).

7. A magnetic fluid seal arrangement for a large shaft diameter centrifugal compressor according to claim 1 wherein: the bottom of the labyrinth seal ring (17) is abutted to the outer wall of the shaft sleeve (1), and one side wall of the labyrinth seal ring (17) is detachably connected with the bearing end cover (20).

8. The magnetic fluid seal device for a large shaft diameter centrifugal compressor according to claim 1, wherein: the sealing seat (27) is provided with a stainless steel rubber sealing ring (3) for positioning and pressing the bearing (5).

9. The magnetic fluid seal device for a large shaft diameter centrifugal compressor according to claim 1, wherein: the sealing seat (27) and the centrifugal compressor shell (11) are connected through a third screw (8); the sealing seat (27) is connected with the cooling jacket shell (13) through a second screw (7); the bearing end cover (20) is connected with the cooling jacket shell (13) through a fourth screw (12); the labyrinth sealing ring (17) is connected with the bearing end cover (20) through a fifth screw (15).