CN217130341U

CN217130341U - Mechanical shaft seal structure of screw compressor

Info

Publication number: CN217130341U
Application number: CN202220708789.6U
Authority: CN
Inventors: 井炳; 余京京; 王英铧
Original assignee: Shanghai Hanbell Precise Machinery Co ltd
Current assignee: Shanghai Hanbell Precise Machinery Co ltd
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2022-08-05
Anticipated expiration: 2032-03-25

Abstract

The utility model discloses a screw compressor's mechanical type bearing seal structure, it includes axis of rotation, seal assembly and axle closing cap, the axis of rotation is located to the seal assembly cover, seal assembly sets up in the axle closing cap, the internal face of axle closing cap has a plurality of slot, seal assembly's surface has the step portion that a plurality of distributes in proper order, a plurality of step portion is last all to have inside sunken recess, a plurality of step portion stretches into to a plurality of slot respectively to realize seal assembly and the sealed of axle closing cap. Will form stairstepping labyrinth structure through step portion and slot between seal assembly and the axle closing cap for adopt stairstepping labyrinth seal's principle to form sealedly to the oil gas mixture of inner chamber, labyrinth structure forms effective seal to gaseous through progressively reducing atmospheric pressure, and stairstepping structure can effectively block to retrieve especially wherein oil drips, and non-contact seal structure has effectively ensured screw compressor's mechanical type bearing seal structure's stability, and the quality of being convenient for management and control reduces the maintenance cost.

Description

Mechanical shaft seal structure of screw compressor

Technical Field

The utility model relates to a screw compressor's mechanical type bearing seal structure.

Background

At present, an extending shaft of a screw type air compressor main machine is usually provided with a lip seal or a mechanical shaft seal. The concrete structure of using lip seal is shown in figure 1, the shaft sleeve 3 is sleeved on the shaft 4 and rotates along with the shaft 4, the shaft seal 2 is arranged on the shaft seal cover 1, and the lip with a spiral thread line on the shaft seal 2 is contacted with the shaft sleeve 3 for friction seal. The lip edge on the shaft seal 2 is made of PTFE material, and has short service life and easy damage. The specific structure of the mechanical shaft seal is shown in fig. 2, a seal ring 8 is arranged between a stationary ring 7 and a shaft seal cover plate 5, a movable ring 6 is sleeved on a shaft and rotates along with the shaft seal, and the end surface of the movable ring keeps attached to the stationary ring 7 and slides relative to the stationary ring under the action of fluid pressure and spring elasticity and the pressing action of the shaft seal cover plate 5, so that sealing is formed. The problems of large abrasion and short service life of the mechanical shaft seal generally exist.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming the above-mentioned not enough of current existence, the utility model provides a screw compressor's mechanical type bearing seal structure.

The utility model discloses a realize through following technical scheme:

the mechanical shaft seal structure of the screw compressor comprises a rotating shaft, a sealing assembly and a shaft sealing cover, wherein the sealing assembly is sleeved on the rotating shaft and rotates along with the rotating shaft, the sealing assembly is arranged in the shaft sealing cover, a plurality of grooves are formed in the inner wall surface of the shaft sealing cover, a plurality of step portions which are distributed in sequence are arranged on the outer surface of the sealing assembly, inward concave grooves are formed in the plurality of step portions, and the plurality of step portions respectively extend into the plurality of grooves to seal the sealing assembly and the shaft sealing cover.

Further, seal assembly includes gas seal ring and lock nut, the gas seal ring cover is located the axis of rotation, a plurality of step portion all is located the surface of gas seal ring, lock nut threaded connection in the axis of rotation and compress tightly to lean on in the gas seal ring.

Furtherly, a plurality of step portion and a plurality of be formed with the ladder groove between the slot, the bottom in ladder groove is along keeping away from the direction downward sloping extension of axle closing cap.

Further, the bottom of the shaft sealing cover is provided with an oil return hole.

Further, the oil return hole extends upwards from the bottom surface of the shaft cover to the bottom of the sealing assembly.

Further, the number of the step parts is four.

Further, the groove is recessed inward in a radial direction of the rotating shaft from an end surface of the stepped portion away from the rotating shaft.

Further, the cross-sectional shape of the groove is trapezoidal.

The beneficial effects of the utility model reside in that:

the utility model discloses a screw compressor's mechanical type bearing seal structure will form stairstepping labyrinth structure through step portion and slot between seal assembly and the axle closing cap for adopt stairstepping labyrinth seal's principle to form sealedly to the oil-gas mixture of inner chamber, labyrinth structure forms effectively sealedly to gaseous through progressively reducing atmospheric pressure, stairstepping structure can effectively block to retrieve especially wherein oil drips, and non-contact seal structure has effectively ensured screw compressor's mechanical type bearing seal structure's stability, the quality management and control of being convenient for, reduce the maintenance cost.

Drawings

FIG. 1 is a schematic diagram showing the internal structure of a lip seal used for an extension shaft of a screw air compressor main unit in the prior art.

FIG. 2 is a schematic diagram of the internal structure of a protruding shaft of a screw air compressor main unit using a mechanical shaft seal in the prior art.

Fig. 3 is a schematic view of an internal structure of a mechanical shaft seal structure of a screw compressor according to an embodiment of the present invention.

Fig. 4 is a partially enlarged view of a portion a in fig. 3.

Detailed Description

The following description of the embodiments refers to the accompanying drawings, which are included to illustrate specific embodiments in which the invention may be practiced.

As shown in fig. 3 and 4, the present embodiment discloses a mechanical shaft seal structure of a screw compressor, the mechanical shaft seal structure of the screw compressor includes a rotating shaft 10, a sealing assembly 20 and a shaft sealing cover 30, the sealing assembly 20 is sleeved on the rotating shaft 10 and rotates along with the rotating shaft 10, the sealing assembly 20 is disposed in the shaft sealing cover 30, an inner wall surface of the shaft sealing cover 30 has a plurality of grooves 31, an outer surface of the sealing assembly 20 has a plurality of step portions 23 distributed in sequence, each of the plurality of step portions 23 has an inward recessed groove 231, and the plurality of step portions 23 respectively extend into the plurality of grooves 31, so as to realize the sealing between the sealing assembly 20 and the shaft sealing cover 30.

The rotation of the rotating shaft 10 will drive the sealing component 20 to rotate together, the shaft sealing cover 30 will be fixed with the box body, a stepped labyrinth structure will be formed between the sealing component 20 and the shaft sealing cover 30 through the stepped part 23 and the groove 31, the oil-gas mixture will pass through the stepped labyrinth structure formed by the stepped part 23 and the groove 31, the oil-gas mixture passes through a plurality of throttling gaps and expansion cavities, so that great energy loss is generated, the air pressure is greatly reduced, the leakage is difficult, and the purpose of sealing gas is achieved; the oil-gas mixture in the inner cavity is sealed by adopting the stepped labyrinth seal principle, and the labyrinth structure effectively seals gas by gradually reducing the gas pressure. Meanwhile, oil drops in the oil gas are blocked by the step part 23 and the groove 31 and flow back to the cavity along the flow direction, and the stepped structure can effectively block and recover the oil drops in particular. And the non-contact sealing structure effectively ensures the stability of the mechanical shaft seal structure of the screw compressor, is convenient for quality control and reduces the maintenance cost.

The sealing assembly 20 comprises an air seal ring 21 and a locking nut 22, the rotating shaft 10 is sleeved with the air seal ring 21, a plurality of step portions 23 are located on the outer surface of the air seal ring 21, and the locking nut 22 is in threaded connection with the rotating shaft 10 and tightly pressed against the air seal ring 21. The air seal ring 21 is sleeved on the outer peripheral surface of the rotating shaft 10, and the locking nut 22 is screwed to move on the rotating shaft 10, so that the locking nut 22 abuts against the air seal ring 21 and tightly presses and fixes the air seal ring 21.

A stepped groove is formed between the plurality of stepped portions 23 and the plurality of grooves 31, and the bottom of the stepped groove extends downward in a direction away from the shaft cover 30. The bottom of the stepped trough has a downward slope extending into the tank such that oil droplets between the seal assembly 20 and the shaft cover 30 will flow back into the chamber through the stepped trough.

The bottom of the shaft cover 30 has an oil return hole 32. Wherein the oil return hole 32 extends upward from the bottom surface of the shaft cover 30 to the bottom of the seal assembly 20. The oil return hole 32 is positioned at one end of the stepped groove, which is back to the box body, oil drops in the oil gas are blocked by the stepped groove, most of the oil drops flow back into the cavity along the stepped groove, and a small part of the oil drops overflow and are led out to the cavity or the oil collector through the oil return hole 32 through a pipeline, so that the sealing of the lubricating oil is realized.

In the present embodiment, the number of the steps 23 is four. So that four labyrinth structures are formed between the step part 23 and the groove 31, the oil-gas mixture passes through four throttling gaps and an expansion cavity to generate great energy loss, the air pressure is greatly reduced, the leakage is difficult to occur, and the purpose of sealing the gas is achieved.

The groove 231 is recessed inward in the radial direction of the rotating shaft 10 from the end surface of the step portion 23 away from the rotating shaft 10. Oil drops in the stepped groove flow into the groove 231, so that the stability of the mechanical shaft seal structure is effectively guaranteed by the non-contact sealing structure, the quality control is facilitated, and the maintenance cost is reduced. Preferably, the cross-sectional shape of the groove 231 is trapezoidal. Simple structure and convenient processing and manufacturing.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention, which is defined by the appended claims.

Claims

1. The mechanical shaft seal structure of the screw compressor is characterized by comprising a rotating shaft, a sealing assembly and a shaft sealing cover, wherein the sealing assembly is sleeved on the rotating shaft and rotates along with the rotating shaft, the sealing assembly is arranged in the shaft sealing cover, a plurality of grooves are formed in the inner wall surface of the shaft sealing cover, a plurality of stepped portions which are distributed in sequence are arranged on the outer surface of the sealing assembly, a plurality of concave grooves are formed in the stepped portions, and the plurality of stepped portions respectively extend into the plurality of grooves so as to seal the sealing assembly and the shaft sealing cover.

2. The mechanical shaft seal structure of a screw compressor according to claim 1, wherein the sealing assembly includes an air seal ring and a lock nut, the air seal ring is sleeved on the rotating shaft, the plurality of steps are located on an outer surface of the air seal ring, and the lock nut is screwed on the rotating shaft and tightly pressed against the air seal ring.

3. The mechanical shaft seal structure of a screw compressor according to claim 1, wherein a stepped groove is formed between the plurality of stepped portions and the plurality of grooves, and a bottom of the stepped groove extends obliquely downward in a direction away from the shaft cover.

4. The mechanical shaft seal structure of a screw compressor according to claim 1, wherein the bottom of the shaft cover has an oil return hole.

5. The screw compressor mechanical shaft seal structure according to claim 4, wherein the oil return hole extends upward from a bottom surface of the shaft cover to a bottom of the seal assembly.

6. The mechanical shaft seal structure of a screw compressor according to claim 1, wherein the number of the stepped portions is four.

7. The mechanical shaft seal structure of a screw compressor according to claim 1, wherein said groove is recessed inward in a radial direction of said rotary shaft from an end face of said stepped portion away from said rotary shaft.

8. The mechanical shaft seal structure of a screw compressor according to claim 1, wherein a cross-sectional shape of the groove is a trapezoid.