A labyrinth brush type composite seal structure automatically adjusts gap by using air pressure difference

Abstract

The application belongs to the technical field of mechanical seal and specifically discloses a labyrinth brush type composite sealing structure capable of automatically adjusting a gap by utilizing air pressure difference, wherein the labyrinth sealing structure is sleeved outside a machine body; an air inlet structure is arranged between the embedded sealing structure and the labyrinth sealing structure; a pressure storage air structure is arranged between the embedded sealing structure and the labyrinth sealing structure; an inner inclined wedge-shaped sealing ring is arranged between the embedded sealing structure and the labyrinth sealing structure; a main elastic element is arranged inside the embedded sealing structure, and an end of the main elastic element is attached to the other end of the inner inclined wedge-shaped sealing ring; the sealing device is driven to work by utilizing the pneumatic principle; the contact condition of the brush wire and the rotor is adjusted according to the interaction of the pneumatic force under high pressure drop and the elastic force of the elastic element, so that the best sealing state can be achieved, and the gas leakage amount can be maximally reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical sealing, in particular to a labyrinth brush type composite sealing structure capable of automatically adjusting gap by using pressure difference. BACKGROUND

[0002] Brush seal has been applied to turbomachinery such as aero-engine, industrial gas turbine and steam turbine. In the field of aviation, the application of brush seal is an important means to improve the performance of aero-engine;

[0003] The excellent sealing performance of brush seal is due to the flexibility of brush bundle and the "pressure closing" effect. Tens of thousands of fine brush filaments are inclined at an angle of 30-60 degrees to the normal direction of the rotor surface. The flexibility of the brush bundle allows the brush bundle to be retreating and following when the rotor instantaneously jumps radially. The "pressure closing" effect refers to the fact that the brush filaments will be blown towards the rotor by the strong leakage flow in the radial direction under pressure difference, closing or reducing the possible gap between the brush bundle and the rotor. After a long period of wear, the "pressure closing" effect is not enough to close the larger gap between the brush bundle and the rotor. The gap between the brush bundle and the rotor will greatly increase the leakage of the brush seal, leading to sealing failure.

[0004] Currently, since the free end of the brush filaments of the existing brush seal is in flat and gapless contact with the surface of the rotor, in actual use, the tip of the brush filament will gradually wear, increasing the leakage of the fluid and reducing the service life of the sealing structure. In addition, compared with the existing sealing structure, the existing sealing structure for adjusting the gap between the brush bundle and the rotor is based on magnetic effect, transmission gear adjustment and other manual operation modes to reduce the wear of the sealing tip. On the one hand, it increases the labor cost, and on the other hand, it cannot meet the best sealing conditions while reducing wear. SUMMARY

[0005] The present application aims to provide a labyrinth brush type composite sealing structure capable of automatically adjusting gap by using pressure difference to solve the problems raised in the background.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a labyrinth brush type composite sealing structure capable of automatically adjusting gap by using pressure difference, comprising:

[0007] a fuselage, a sealing assembly is arranged on the fuselage, the sealing assembly comprises a labyrinth sealing structure, an air inlet structure, a pressure storage air structure, an inner inclined wedge-shaped sealing ring, an auxiliary wedge-shaped sealing ring two and a main elastic element;

[0008] The labyrinth seal structure is sleeved on the outside of the fuselage, the embedded seal structure is sleeved on the outside of the fuselage, the inside of the embedded seal structure is a hollow structure, the embedded seal structure is sleeved on the outside of the labyrinth seal structure, a spacing is arranged between the embedded seal structure and the labyrinth seal structure, and the end of the embedded seal structure is flush with the end surface of the labyrinth seal structure.

[0009] A gas inlet structure is arranged between the embedded seal structure and the labyrinth seal structure, the outside of the gas inlet structure is attached to the embedded seal structure and the labyrinth seal structure respectively, and the end of the gas inlet structure is flush with the embedded seal structure and the labyrinth seal structure.

[0010] A pressure storage gas structure is arranged between the embedded seal structure and the labyrinth seal structure, the outside of the pressure storage gas structure is attached to the embedded seal structure and the labyrinth seal structure respectively, and the end of the pressure storage gas structure is attached to the gas inlet structure.

[0011] An inner inclined wedge-shaped seal ring is arranged between the embedded seal structure and the labyrinth seal structure, the outside of the inner inclined wedge-shaped seal ring is attached to the embedded seal structure and the labyrinth seal structure respectively, one end of the inner inclined wedge-shaped seal ring is attached to the pressure storage gas structure, the inside of the embedded seal structure is provided with a main elastic element, and the end of the main elastic element is attached to the other end of the inner inclined wedge-shaped seal ring.

[0012] Preferably, an auxiliary wedge-shaped seal ring one is arranged between the embedded seal structure and the labyrinth seal structure, the end of the auxiliary wedge-shaped seal ring one is attached to the labyrinth seal structure, the position close to the end of the inner inclined wedge-shaped seal ring is inclined, the outside of the auxiliary wedge-shaped seal ring one is attached to the inside of the inner inclined wedge-shaped seal ring, the auxiliary wedge-shaped seal ring one is sleeved on the outside of the labyrinth seal structure, and an auxiliary elastic element one is arranged between the auxiliary wedge-shaped seal ring one and the labyrinth seal structure.

[0013] Preferably, a brush wire wedge-shaped seal ring is arranged between the embedded seal structure and the labyrinth seal structure, the outside of the brush wire wedge-shaped seal ring is inclined, the outside of the brush wire wedge-shaped seal ring is attached to the inside of the inner inclined wedge-shaped seal ring, and one end of the brush wire wedge-shaped seal ring is attached to the auxiliary wedge-shaped seal ring one.

[0014] Preferably, an auxiliary wedge-shaped seal ring two is arranged in the embedded seal structure, the end of the auxiliary wedge-shaped seal ring two is attached to the end of the brush wire wedge-shaped seal ring, a honeycomb baffle structure is arranged on the outside of the fuselage, the auxiliary wedge-shaped seal ring two is sleeved on the outside of the honeycomb baffle structure, and an auxiliary elastic element two is arranged between the auxiliary wedge-shaped seal ring two and the honeycomb baffle structure.

[0015] The chimeric sealing structure is the outermost structure frame, the air inlet structure with the annular ventilation groove is fixed with the pressure storage gas structure, and is fixed between the labyrinth sealing structures through the clamping groove. The honeycomb baffle structure is fixed at the lower right end of the chimeric sealing structure.

[0016] The brush filament wedge-shaped sealing ring is a sealing ring with a certain taper on the outer diameter, a brush ring is formed by using high-performance welded brush filaments, and is in contact with three sealing elastic rings with the same taper on the inner diameter; the three elastic rings are constrained by three thin elastic sheets, respectively, and are wedged under the constraint of the constraint force; the three thin elastic sheets are fixed on the chimeric sealing structure, the labyrinth sealing structure, and the honeycomb baffle structure through threaded structures, respectively.

[0017] When the engine starts to work, the gas flow and pressure in the high-pressure area at the left end of the sealing body are continuously increased with the rotating speed, the generated gas is sucked through the left end air inlet structure and enters the pressure storage gas structure; when the working gas pressure is large enough, the gas sucked through the pressure storage gas structure forms high-pressure gas; under the pressure of the high-pressure gas from the pressure storage gas structure, a rightward sliding thrust is generated on the inwardly inclined wedge-shaped sealing ring, and the elastic force of the main elastic element at the right end of the inwardly inclined wedge-shaped sealing ring is resisted, when the pressure is much larger than the elastic force, the inwardly inclined wedge-shaped sealing ring is forced to move to the right end, and the brush filament wedge-shaped sealing ring in contact with it is forced to move to the radial direction of the rotor, and the tightness of the brush filament tip and the rotor is tightened, and finally the thrust generated by the gas pressure and the elastic force of the elastic system reach a certain balance state, further controlling the radial gap between the brush filament bundle and the rotor.

[0018] When the engine is just running and the running is finished, the thrust generated by the gas pressure is not enough to resist the rebound force generated by the elastic system, the inwardly inclined wedge-shaped sealing ring is pushed to move to the left under the rebound action of the auxiliary wedge-shaped sealing ring two, and gradually returns to the initial position, the tightness of the brush filament tip and the rotor is reduced, and the invalid loss of the brush filament is reduced;

[0019] The sealing structure is mainly applied to aero-engines, steam turbine drive shafts and the like, prevents gas from leaking along the axial direction of the drive shaft, and the shaft surface contacted by the free end of the brush is generally sprayed with a layer of wear-resistant material to prevent the brush from scratching the shaft diameter during work, and the friction loss of the brush can be reduced;

[0020] The brush filaments of the brush sealing part are arranged in a circle along the rotating direction of the rotor, and are high-temperature-resistant cobalt-based alloy filaments (containing more than 0% of cobalt), which can withstand high temperatures above 00 degrees Celsius without deformation. During operation, the scattered brush filament bundle has a wind resistance effect similar to that of a protective forest, which plays a sealing effect and can adapt to the transient jumping of the rotor, restore the original gas seal gap, and ensure the use effect for a long time;

[0021] The jet flow directly impacts on the brush bundle from the labyrinth leakage, part of the jet flow penetrates into the next chamber through the porous medium brush bundle, and the other part forms a reflux in the chamber to form a larger vortex flow, which converts the kinetic energy of the leakage jet flow into heat energy. The pressure drop of the leakage flow after passing through the brush bundle is greater than that of passing through the labyrinth teeth. Thus, the brush bundle can effectively prevent the leakage flow and improve the sealing effect.

[0022] The leakage amount of the sealing structure is significantly less than that of the ordinary flat-tooth labyrinth sealing structure, and the brush bundle is easier to install axially than the stepped-tooth labyrinth sealing structure. The friction and wear between the brush bundle and the rotor are less than those of the ordinary brush sealing structure, which overcomes the problem of excessive wear of the rotor surface leading to continuous increase of leakage, and improves the reliability and service life of the brush sealing.

[0023] Compared with the prior art, the beneficial effects of the present application are:

[0024] The structure analyzes the deficiencies of the prior art, mainly uses the aerodynamic principle to drive the sealing device to work, adjusts the contact between the brush wire and the rotor according to the interaction of the aerodynamic force under high pressure drop and the elastic force of the elastic element, can achieve the best sealing state, and can minimize the gas leakage. Under the condition of not working and initial low pressure working, the elastic return characteristic of the sealing elastic ring is used to adjust the initial sealing state, the contact between the brush wire tip and the rotor is weak, which can effectively reduce the invalid wear of the brush wire tip relative to the rotor, and improve the service life of the brush sealing. Under the condition of high-speed and high-pressure normal sealing work, the tightness between the brush wire tip and the rotor can be increased, and the sealing performance can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 It is a schematic diagram of the overall structure of the present application;

[0026] Fig. 2 It is a schematic diagram of the local enlarged structure of the present application.

[0027] In the figure: 1, embedded sealing structure; 2, labyrinth sealing structure; 3, air inlet structure; 4, pressure storage air structure; 5, inwardly inclined wedge-shaped sealing ring; 6, brush wire wedge-shaped sealing ring; 7, auxiliary wedge-shaped sealing ring I; 8, auxiliary wedge-shaped sealing ring II; 9, main elastic element; 10, auxiliary elastic element I; 11, auxiliary elastic element II; 12, honeycomb baffle structure; 13, machine body. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0029] In the description of the present application, it should be noted that the terms "vertical", "upper", "lower", "horizontal" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0030] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] Please refer to Figs. 1-2 The present application provides a technical scheme: a labyrinth brush type composite sealing structure for automatically adjusting the gap by using air pressure difference, comprising:

[0032] The machine body 13 is provided with a sealing assembly, the sealing assembly comprises a labyrinth sealing structure 2, an air inlet structure 3, a pressure storage gas structure 4, an inner inclined wedge-shaped sealing ring 5, an auxiliary wedge-shaped sealing ring 8, and a main elastic element 9.

[0033] The labyrinth sealing structure 2 is sleeved on the outside of the machine body 13, the embedded sealing structure 1 is sleeved on the outside of the machine body 13, the inside of the embedded sealing structure 1 is a hollow structure, the embedded sealing structure 1 is sleeved on the outside of the labyrinth sealing structure 2, and the embedded sealing structure 1 and the labyrinth sealing structure 2 are provided with a spacing, and the end of the embedded sealing structure 1 is flush with the end surface of the labyrinth sealing structure 2.

[0034] The embedded sealing structure 1 and the labyrinth sealing structure 2 are provided with the air inlet structure 3, the outside of the air inlet structure 3 is respectively attached to the embedded sealing structure 1 and the labyrinth sealing structure 2, and the end of the air inlet structure 3 is flush with the embedded sealing structure 1 and the labyrinth sealing structure 2.

[0035] The embedded sealing structure 1 and the labyrinth sealing structure 2 are provided with the pressure storage gas structure 4, the outside of the pressure storage gas structure 4 is respectively attached to the embedded sealing structure 1 and the labyrinth sealing structure 2, and the end of the pressure storage gas structure 4 is attached to the air inlet structure 3.

[0036] The inner inclined wedge-shaped sealing ring 5 is arranged between the interlocking sealing structure 1 and the labyrinth sealing structure 2, and the outer side of the inner inclined wedge-shaped sealing ring 5 is respectively attached to the interlocking sealing structure 1 and the labyrinth sealing structure 2, and one end of the inner inclined wedge-shaped sealing ring 5 is attached to the pressure storage gas structure 4.

[0037] Further, the interlocking sealing structure 1 and the labyrinth sealing structure 2 are provided with an auxiliary wedge-shaped sealing ring one 7, the end of the auxiliary wedge-shaped sealing ring one 7 is attached to the labyrinth sealing structure 2, the position of the inner side of the inner inclined wedge-shaped sealing ring 5 close to the end is inclined, the outer side of the auxiliary wedge-shaped sealing ring one 7 is attached to the inner side of the inner inclined wedge-shaped sealing ring 5, the auxiliary wedge-shaped sealing ring one 7 is sleeved on the outer side of the labyrinth sealing structure 2, and the auxiliary wedge-shaped sealing ring one 7 and the labyrinth sealing structure 2 are provided with an auxiliary elastic element one 10.

[0038] Further, the interlocking sealing structure 1 and the labyrinth sealing structure 2 are provided with a brush wire wedge-shaped sealing ring 6, the outer side of the brush wire wedge-shaped sealing ring 6 is inclined, the outer side of the brush wire wedge-shaped sealing ring 6 is attached to the inner side of the inner inclined wedge-shaped sealing ring 5, and one end of the brush wire wedge-shaped sealing ring 6 is attached to the auxiliary wedge-shaped sealing ring one 7.

[0039] Further, the interlocking sealing structure 1 is provided with an auxiliary wedge-shaped sealing ring two 8 in the inside, the end of the auxiliary wedge-shaped sealing ring two 8 is attached to the end of the brush wire wedge-shaped sealing ring 6, the outer side of the fuselage 13 is provided with a honeycomb baffle structure 12, the auxiliary wedge-shaped sealing ring two 8 is sleeved on the outer side of the honeycomb baffle structure 12, and the auxiliary wedge-shaped sealing ring two 8 and the honeycomb baffle structure 12 are provided with an auxiliary elastic element two 11.

[0040] The interlocking sealing structure 1 is the outermost structure frame, the air inlet structure 3 with the annular air vent groove and the pressure storage gas structure 4 are fixed to each other and are fixed in the interlocking sealing structure 1 and the labyrinth sealing structure 2 through the clamping groove. The honeycomb baffle structure 12 is fixed to the lower right end of the interlocking sealing structure 1.

[0041] The brush wire wedge-shaped sealing ring 6 is a sealing ring with a certain taper in the outer diameter, a high-performance welded brush wire bundle is used to form a brush ring, and the brush ring is in contact with three sealing elastic rings 5, 7 and 8 with the same taper in the inner diameter; the three elastic rings 5, 7 and 8 are respectively constrained by three sheet elastic sheets 9, 10 and 11, and are tightly wedged under the action of the constraint force; the three sheet elastic sheets 9, 10 and 11 are respectively fixed on the interlocking sealing structure 1, the labyrinth sealing structure 2 and the honeycomb baffle structure 12 through the threaded structure.

[0042] When the engine starts to work, the gas flow and pressure in the high pressure area at the left end of the sealing body increase with the rotating speed, the generated gas is sucked through the left end intake structure 3 and enters the pressure storage gas structure 4; when the working gas pressure is large enough, the gas sucked through the pressure storage gas structure 4 forms high pressure gas; under the compression of the high pressure gas from the pressure storage gas structure 4, a rightward sliding thrust is generated on the inwardly inclined wedge-shaped sealing ring 5, and the right end of the inwardly inclined wedge-shaped sealing ring 5 resists the elastic force of the main elastic element 5 to the left of the inwardly inclined wedge-shaped sealing ring 5; when the pressure is much greater than the elastic force, the inwardly inclined wedge-shaped sealing ring 5 is forced to move to the right end, and the brush wire wedge-shaped sealing ring 6 in contact with it is forced to move to the radial direction close to the rotor, and the tightness of the brush wire tip with the rotor is tightened, and finally the thrust generated by the gas pressure and the elastic force of the elastic system reach a certain balance state, further controlling the radial gap between the brush wire bundle and the rotor.

[0043] When the engine is just running and the running is over, the thrust generated by the gas pressure is not enough to resist the rebound force generated by the elastic system, the inwardly inclined wedge-shaped sealing ring 5 is pushed to the left by the rebound action of the auxiliary wedge-shaped sealing ring 8, and gradually returns to the initial position, the tightness of the brush wire tip with the rotor is reduced, and the invalid loss of the brush wire is reduced;

[0044] The sealing structure is mainly applied to aero-engine, turbine transmission shaft and the like, and prevents gas from leaking along the axial direction of the transmission shaft, and the shaft surface in contact with the free end of the brush is generally sprayed with a layer of wear-resistant material to prevent the brush from scratching the shaft diameter during work, and the friction loss of the brush can be reduced at the same time;

[0045] The brush wire of the brush sealing part is a circle of cobalt-based alloy wire (containing more than 50% of cobalt) which can withstand high temperature above 1200 degrees Celsius without deformation, and when running, the scattered brush wire bundle is similar to the wind resistance effect of a protective forest, which plays a sealing effect and can adapt to the transient jump of the rotor, restore the original gas seal gap, and ensure the use effect for a long time;

[0046] The jet flow from the labyrinth leakage directly hits the brush wire bundle, part of which penetrates through the porous medium brush wire bundle into the next chamber, and the other part forms a backflow in the chamber to form a larger vortex flow, which converts the kinetic energy of the leakage jet flow into heat energy, and the pressure drop of the leakage flow after passing through the brush wire bundle is greater than that when passing through the labyrinth teeth, so that the brush wire bundle can effectively prevent the leakage flow and improve the sealing effect;

[0047] The leakage amount of the sealing structure is significantly smaller than that of the ordinary flat-tooth labyrinth sealing structure, and it is easier to install axially than the stepped-tooth labyrinth sealing structure, the friction and wear between the brush bundle and the rotor are smaller than those of the ordinary brush sealing structure, which overcomes the problem that excessive wear of the rotor surface leads to continuous increase of leakage, and improves the reliability and service life of the brush sealing.

[0048] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A labyrinth brush composite sealing structure that automatically adjusts the gap using air pressure difference, characterized in that: include; The fuselage (13) is provided with a sealing assembly, which includes a labyrinth sealing structure (2), an air intake structure (3), a pressurized gas structure (4), an inwardly inclined wedge sealing ring (5), an auxiliary wedge sealing ring II (8), and a main elastic element (9). The labyrinth-type sealing structure (2) is fitted on the outside of the fuselage (13), the fitting sealing structure (1) is fitted on the outside of the fuselage (13), and the interior of the fitting sealing structure (1) is a hollow structure. The fitting sealing structure (1) is fitted on the outside of the labyrinth-type sealing structure (2), and there is a gap between the fitting sealing structure (1) and the labyrinth-type sealing structure (2). The end of the fitting sealing structure (1) is flush with the end surface of the labyrinth-type sealing structure (2). An air intake structure (3) is provided between the interlocking sealing structure (1) and the labyrinth sealing structure (2). The outer side of the air intake structure (3) is respectively attached to the interlocking sealing structure (1) and the labyrinth sealing structure (2). The end of the air intake structure (3) is flush with the interlocking sealing structure (1) and the labyrinth sealing structure (2). A pressurized gas structure (4) is provided between the interlocking sealing structure (1) and the labyrinth sealing structure (2). The outer side of the pressurized gas structure (4) is respectively attached to the interlocking sealing structure (1) and the labyrinth sealing structure (2), and the end of the pressurized gas structure (4) is attached to the air intake structure (3). An inclined wedge-shaped sealing ring (5) is provided between the interlocking sealing structure (1) and the labyrinth sealing structure (2). The outer side of the inclined wedge-shaped sealing ring (5) is respectively attached to the interlocking sealing structure (1) and the labyrinth sealing structure (2). One end of the inclined wedge-shaped sealing ring (5) is attached to the pressurized gas structure (4). The interior of the interlocking sealing structure (1) is provided with a main elastic element (9). The end of the main elastic element (9) is attached to the other end of the inclined wedge-shaped sealing ring (5). A brush wedge-shaped sealing ring (6) is provided between the interlocking sealing structure (1) and the labyrinth sealing structure (2). The outer side of the brush wedge-shaped sealing ring (6) is inclined. The outer side of the brush wedge-shaped sealing ring (6) is in contact with the inner side of the inclined wedge-shaped sealing ring (5). One end of the brush wedge-shaped sealing ring (6) is in contact with the auxiliary wedge-shaped sealing ring (7). The internal part of the interlocking sealing structure (1) is provided with an auxiliary wedge sealing ring 2 (8). The end of the auxiliary wedge sealing ring 2 (8) is in contact with the end of the brush wedge sealing ring (6). The inwardly inclined wedge sealing ring (5) can be pushed to the left by the rebound of the auxiliary wedge sealing ring 2 (8).

2. The labyrinth brush composite sealing structure for automatically adjusting the gap using air pressure difference as described in claim 1, characterized in that: An auxiliary wedge-shaped sealing ring (7) is provided between the interlocking sealing structure (1) and the labyrinth sealing structure (2). The end of the auxiliary wedge-shaped sealing ring (7) is fitted with the labyrinth sealing structure (2). The inner side of the inclined wedge-shaped sealing ring (5) is inclined near the end. The outer side of the auxiliary wedge-shaped sealing ring (7) is fitted with the inner side of the inclined wedge-shaped sealing ring (5). The auxiliary wedge-shaped sealing ring (7) is fitted on the outer side of the labyrinth sealing structure (2). An auxiliary elastic element (10) is provided between the auxiliary wedge-shaped sealing ring (7) and the labyrinth sealing structure (2).

3. The labyrinth brush composite sealing structure for automatically adjusting the gap using air pressure difference as described in claim 1, characterized in that: A honeycomb baffle structure (12) is provided on the outer side of the fuselage (13), and an auxiliary wedge sealing ring (8) is fitted on the outer side of the honeycomb baffle structure (12). An auxiliary elastic element (11) is provided between the auxiliary wedge sealing ring (8) and the honeycomb baffle structure (12).

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