CN212775561U

CN212775561U - Sealing structure at shaft extension position of screw ORC (organic Rankine cycle) expander

Info

Publication number: CN212775561U
Application number: CN202021294639.2U
Authority: CN
Inventors: 李明; 霍正齐; 刘进亮; 夏航; 王博; 李章鹏
Original assignee: WUHAN NEW WORLD REFRIGERATION INDUSTRIAL CO LTD
Current assignee: WUHAN NEW WORLD REFRIGERATION INDUSTRIAL CO LTD
Priority date: 2020-07-01
Filing date: 2020-07-01
Publication date: 2021-03-23
Anticipated expiration: 2030-07-01

Abstract

The utility model discloses a screw rod ORC expander shaft extension's seal structure, it includes that a pair of lip seal circle, a lip seal and seals with axle sleeve and a lip and use the baffle. The pair of lip seals are installed respectively in the sealed annular that positive rotor exhaust end cover's mating holes both ends were seted up, the lip seals with the axle sleeve with interference fit mode suit on the straight section of thick bamboo of the output shaft of expander positive rotor, the lip seals with the both ends outer wall of axle sleeve respectively with a pair of lip seals between form sealed cooperation relation, form friction fit structure between the mating holes internal face of the outer wall in the middle of the axle sleeve and positive rotor exhaust end cover for the lip seals. The lip seal baffle is tightly fixed on the outer end face of the male rotor exhaust end cover through screws and gaskets distributed along the circumferential direction, so that the axial positions of the lip seal rings are pressed and locked. The sealing structure can ensure the sealing reliability and reduce the leakage risk, and has simpler structure and more convenient installation and maintenance.

Description

Sealing structure at shaft extension position of screw ORC (organic Rankine cycle) expander

Technical Field

The utility model relates to a sealing technique of key part in screw rod ORC expander specifically indicates a seal structure of screw rod ORC expander axle extension department.

Background

The screw ORC expander adopts organic working medium Rankine cycle, the key structural components of the screw ORC expander are provided with a female rotor and a male rotor, a sealing structure is generally arranged at the shaft extension position of the male rotor to ensure the sealing property of the expander, and the sealing structure is a mechanical shaft seal under the common condition. The mechanical shaft seal is composed of a moving ring and a static ring, when the male rotor and the female rotor are meshed, the moving ring rotates along with the male rotor, the static ring keeps still, and an oil friction surface is formed between the moving ring and the static ring.

The working medium of the screw ORC expander is high-temperature and high-pressure organic working medium, so that special lubricating oil is needed for cooling and lubricating the male rotor and the female rotor, and a small amount of organic working medium can be dissolved in the lubricating oil. The lubricating oil is more expensive and has a lower charge than a refrigeration compressor of the same type. If a conventional shaft seal is used, firstly, the material of an O-shaped sealing ring in the shaft seal needs to be specially selected, and the friction surface between a moving ring and a static ring is quickly abraded due to the precipitation of an organic working medium in lubricating oil in the operation process of the expansion machine, so that the leakage amount of the lubricating oil is large, potential safety hazards exist, and resource waste is caused. Meanwhile, the conventional mechanical shaft seal device has high cost and complex structure, and the operation procedures are complicated during installation and later maintenance and replacement.

Therefore, the use of conventional mechanical shaft seals in screw ORC expanders cannot meet the use requirements of the expanders for a long time at present. In order to solve the above problems, those skilled in the art have been trying to find a sealing structure with better sealing effect and longer service life, but no satisfactory progress has been made so far.

Disclosure of Invention

The utility model aims at providing a seal structure of screw ORC expander shaft extension department. The sealing structure can ensure the sealing reliability and reduce the leakage risk, and has simpler structure and more convenient installation and maintenance.

In order to achieve the above object, the utility model provides a screw ORC expander shaft extension's seal structure sets up between the output shaft of expander male rotor and the mating holes of male rotor exhaust end cover, and it includes a pair of lip seal circle, a lip seal with the axle sleeve and a lip seal with the baffle. It is characterized in that: the pair of lip seals are installed respectively in the sealed annular that positive rotor exhaust end cover's mating holes both ends were seted up, the lip seals with the axle sleeve with interference fit mode suit on the straight section of thick bamboo of the output shaft of expander positive rotor, the lip seals with the both ends outer wall of axle sleeve respectively with a pair of lip seals between form sealed cooperation relation, form friction fit structure between the mating holes internal face of the outer wall in the middle of the axle sleeve and positive rotor exhaust end cover for the lip seals. The lip seal baffle is tightly fixed on the outer end face of the male rotor exhaust end cover through screws and gaskets distributed along the circumferential direction, so that the axial positions of the lip seal rings are pressed and locked.

Preferably, the middle outer wall surface of the shaft sleeve for the lip seal is provided with a spiral groove, and the spiral direction of the spiral groove can ensure that the spiral groove can apply pressure to the inner cavity of the expander in the rotating process.

Furthermore, a laser cladding soft metal layer is plated on the inner wall surface of the matching hole of the male rotor exhaust end cover, and the hardness of the laser cladding soft metal layer is lower than that of the outer wall surface of the shaft sleeve for the lip seal.

Furthermore, a laser cladding soft metal layer is plated on the inner wall of the matching hole of the male rotor exhaust end cover, and the hardness of the laser cladding soft metal layer is lower than that of the outer surface of the spiral groove on the shaft sleeve for lip sealing.

Still further, the lower part of the male rotor exhaust end cover is provided with an oil discharge channel, one end of the oil discharge channel is communicated to the outer wall surface of the lip seal shaft sleeve, and the other end of the oil discharge channel is communicated to the external atmosphere of the expander.

The utility model discloses following beneficial effect has:

firstly, a double-lip sealing ring combined structure is adopted, two lip sealing rings are respectively arranged in sealing ring grooves at two ends of a matching hole of an exhaust end cover of the male rotor, and when one lip sealing ring at the inner side leaks, one lip sealing ring at the outer side can still play a sealing role.

And secondly, a shaft sleeve transition structure for lip sealing is adopted, the shaft sleeve for lip sealing is in interference fit with a straight cylinder section at the output end of the male rotor of the expansion machine, and a pair of lip sealing rings are in rotary sealing fit with the outer wall surfaces at two ends of the shaft sleeve for lip sealing, so that the lip sealing rings are prevented from being in direct contact with a shaft extension section of the male rotor of the expansion machine, and the shaft extension section is prevented from being abraded when the male rotor of the expansion machine rotates.

And thirdly, the design of the middle outer wall surface spiral groove of the shaft sleeve for lip sealing is adopted, the spiral groove selects proper rotation direction, pressure towards the inner cavity of the expansion machine can be generated in the rotation process of the male rotor of the expansion machine, and the pressure pushes lubricating oil towards the inner cavity of the expansion machine all the time, so that the leakage of the lubricating oil is further prevented.

And fourthly, the design of plating a laser cladding soft metal layer on the inner wall of the matching hole of the exhaust end cover of the male rotor is adopted, and the hardness of the soft metal layer is lower than the hardness of the outer wall surface of the shaft sleeve for lip sealing or lower than the hardness of the outer surface of the spiral groove of the shaft sleeve for lip sealing, so that the abrasion of the shaft sleeve for lip sealing and the spiral groove thereof in the rotary operation can be greatly reduced, the service life of the shaft sleeve is prolonged, and the sealing effect is enhanced.

And fifthly, by adopting the design of an additional oil discharge channel, a small amount of lubricating oil in the inner cavity of the expansion machine can flow to the outside atmosphere after being depressurized through the internal lip-shaped sealing ring, the shaft sleeve for the lip seal and the spiral groove thereof, and the flowing lubricating oil can also lubricate the friction surface between the laser cladding soft metal layer and the shaft sleeve for the lip seal and the spiral groove thereof, so that the abrasion between the laser cladding soft metal layer and the lip seal is effectively reduced.

Drawings

Fig. 1 is a front view structural diagram of a sealing structure at a shaft extension of the screw ORC expander of the present invention.

Fig. 2 is an enlarged schematic view of a portion a in fig. 1.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

The sealing structure of the shaft extension of the screw ORC expander shown in figures 1 and 2 is arranged between an output shaft of a male rotor 8 of the expander and a matching hole of a male rotor exhaust end cover 1, and mainly comprises a pair of lip-shaped sealing rings 4, a shaft sleeve 5 for lip sealing and a baffle 6 for lip sealing. Wherein:

a pair of lip-shaped sealing rings 4 are respectively installed in sealing ring grooves (not numbered in the figure) formed at two ends of a matching hole of the male rotor exhaust end cover 1, a shaft sleeve 5 for lip sealing is sleeved on a straight cylinder section of an output shaft of the male rotor 8 of the expansion machine in an interference fit mode, and a conical cylinder section of the output shaft of the male rotor 8 of the expansion machine is used for connecting an input end (not shown in the figure) of a generator. The outer wall surfaces at two ends of the shaft sleeve 5 for lip seal are respectively in sealing fit with the lip seal rings 4, and a friction fit structure is formed between the middle outer wall surface of the shaft sleeve 5 for lip seal and the inner wall surface of a matching hole of the male rotor exhaust end cover 1.

In this embodiment, the spiral groove 10 is formed on the middle outer wall surface of the shaft sleeve 5 for lip seal, and the spiral direction of the spiral groove 10 can ensure that the spiral groove applies pressure to the inner cavity 9 of the expander in the rotation process. The inner wall of a matching hole of the male rotor exhaust end cover 1 is plated with a laser cladding soft metal layer 11, and the hardness of the laser cladding soft metal layer 11 is lower than the hardness of the outer surface of a spiral groove 10 on the shaft sleeve 5 for lip seal.

The lip seal retainer 6 is fixed to the outer end surface of the male rotor exhaust end cover 1 by screws 2 and washers 3 distributed in the circumferential direction, and thereby the axial positions of the pair of lip seals 4 are pressed and locked.

In this embodiment, an oil drain passage 7 is provided in the lower part of the male rotor exhaust end cover 1, one end of the oil drain passage 7 opens to the outer wall surface of the lip seal boss 5, and the other end of the oil drain passage 7 opens to the atmosphere outside the expander, and a small amount of the lubricant oil flowing out can be received by a separate container.

The utility model discloses the seal structure's of screw rod ORC expander axle extension department installation and working process as follows:

before the male rotor exhaust end cover 1 is installed, a lip-shaped sealing ring 4 close to an inner cavity 9 of the expander is placed in a sealing ring groove on the inner side of a matching hole of the male rotor exhaust end cover 1, and then the male rotor exhaust end cover 1 is installed on the expander. And then another lip-shaped sealing ring 4 far away from the inner cavity 9 of the expander is placed in a sealing ring groove on the outer side of a matching hole of the male rotor exhaust end cover 1, finally the lip seal is pressed tightly by a baffle 6, a gasket 3 is installed, and a screw 2 is screwed on.

During the operation of the screw ORC expander, pressure of lubricating oil (containing a small amount of organic working medium) with pressure in the inner cavity 9 of the expander can form pressure towards the direction of an output shaft of the male rotor 8 of the expander, on one hand, two lip-shaped sealing rings 4 are arranged to seal the lubricating oil, on the other hand, pressure towards the inner cavity 9 of the expander can be generated by a spiral groove 10 on the shaft sleeve 5 for lip sealing in the rotating process, and the direction of the pressure is opposite to the direction of the pressure generated by the lubricating oil, so that the sealing effect on the lubricating oil can be further improved. Meanwhile, as the oil discharge channel 7 is arranged at the lower part of the male rotor exhaust end cover 1, lubricating oil in the inner cavity 9 of the expander passes through the lip-shaped sealing ring 4 and the spiral groove 10 on the shaft sleeve 5 for lip sealing along the way, and flows out from the oil discharge channel 7 after the pressure is reduced, the flowing lubricating oil can form an oil friction surface between the laser cladding soft metal layer 11 and the spiral groove 10 and well lubricate the oil friction surface, thereby reducing the abrasion between the laser cladding soft metal layer and the spiral groove. When the disassembly and maintenance are needed, the lip-shaped sealing ring 4 can be conveniently replaced by only loosening the screw 2 and the gasket 3 and disassembling the male rotor exhaust end cover 1 and the baffle 6 for lip sealing.

Claims

1. A sealing structure at the shaft extension of a screw ORC expander is arranged between an output shaft of a male rotor (8) of the expander and a matching hole of a male rotor exhaust end cover (1), and comprises a pair of lip-shaped sealing rings (4), a shaft sleeve (5) for lip sealing and a baffle (6) for lip sealing; the method is characterized in that:

the pair of lip-shaped sealing rings (4) are respectively installed in sealing ring grooves formed in two ends of a matching hole of the male rotor exhaust end cover (1), the shaft sleeve (5) for lip sealing is sleeved on a straight cylinder section of an output shaft of the male rotor (8) of the expansion machine in an interference fit mode, outer wall surfaces of two ends of the shaft sleeve (5) for lip sealing respectively form a sealing fit relation with the pair of lip-shaped sealing rings (4), and a friction fit structure is formed between the middle outer wall surface of the shaft sleeve (5) for lip sealing and the inner wall surface of the matching hole of the male rotor exhaust end cover (1);

the lip seal baffle (6) is tightly fixed on the outer end face of the male rotor exhaust end cover (1) through screws (2) and gaskets (3) distributed along the circumferential direction, so that the axial positions of the lip seal rings (4) are pressed and locked.

2. The seal structure at the shaft extension of a screw ORC expander according to claim 1, wherein: a spiral groove (10) is formed in the middle outer wall surface of the shaft sleeve (5) for the lip seal, and the spiral direction of the spiral groove (10) can ensure that the spiral groove can apply pressure to an inner cavity (9) of the expansion machine in the rotating process.

3. The seal structure at the shaft extension of a screw ORC expander according to claim 1, wherein: the inner wall surface of a matching hole of the male rotor exhaust end cover (1) is plated with a laser cladding soft metal layer (11), and the hardness of the laser cladding soft metal layer (11) is lower than that of the outer wall surface of the shaft sleeve (5) for lip seal.

4. The seal structure at the shaft extension of a screw ORC expander according to claim 2, wherein: the inner wall of a matching hole of the male rotor exhaust end cover (1) is plated with a laser cladding soft metal layer (11), and the hardness of the laser cladding soft metal layer (11) is lower than the hardness of the outer surface of a spiral groove (10) on the shaft sleeve (5) for lip sealing.

5. The sealing structure at the shaft extension of a screw ORC expander according to any one of claims 1 to 4, wherein: an oil discharge channel (7) is arranged at the lower part of the male rotor exhaust end cover (1), one end of the oil discharge channel (7) leads to the outer wall surface of the shaft sleeve (5) for lip seal, and the other end of the oil discharge channel (7) leads to the external atmosphere of the expansion machine.