CN216555365U

CN216555365U - Double-end-face mechanical seal

Info

Publication number: CN216555365U
Application number: CN202123308949.2U
Authority: CN
Inventors: 李少峰; 叶传剑; 董军峰; 张炜; 陆俊杰; 洪先志; 包鑫
Original assignee: Ningbo Donglian Mechanical Seal Co ltd
Current assignee: Ningbo Donglian Mechanical Seal Co ltd
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2022-05-17
Anticipated expiration: 2031-12-27

Abstract

The utility model provides a double-end-face mechanical seal which comprises a shaft sleeve, a seal seat, a driving ring, a main static ring and an auxiliary seal assembly, wherein one end of the driving ring is assembled with one end of the shaft sleeve, and the other end of the shaft sleeve is connected with a second mounting seat; the other end of the driving ring is in butt fit with one end of the main static ring in a relatively rotatable manner, one end of the sealing seat is provided with a first static ring groove, and the other end of the main static ring is sealed and can be assembled in the first static ring groove in a sliding manner; a sealing ring and a flexible gasket for preventing particles at the medium end from contacting the sealing ring are arranged between the first static ring groove and the main static ring; one end of the auxiliary sealing component is assembled at the other end of the sealing seat, and the other end of the auxiliary sealing component is assembled with the second mounting seat; the outer side wall of the shaft sleeve is provided with a spiral diversion trench. The utility model provides a double-end-face mechanical seal which is simple in structure, the flushing fluid in a seal cavity circulates smoothly, the cooling effect on a seal face is good, and the sealing performance of a sealing device is ensured.

Description

Double-end-face mechanical seal

Technical Field

The utility model relates to the technical field of mechanical seal, in particular to a double-end-face mechanical seal.

Background

The mechanical seal of the slurry pump is an important and troublesome problem in the chemical industry, and the reliability of the seal plays an important role in the quality and stability of production. For example, most of the existing slurry pumps in the alumina industry are of a single-end-face structure, the slurry in the alumina industry has the characteristics of high solid content, high hardness of solid particles, easiness in condensation of materials and the like, and generates a strong abrasive wear effect on sealing, so that the sealing end face is excessively worn in the early stage to cause material leakage, and the sealing service life is very short.

In the existing mechanical sealing structure applied to the slurry pump, generally, a plurality of parts are axially connected, so that the size is large, and the size of a corresponding mounting cavity is also required to be larger; on the other hand, the manufacturing cost is also increased; in addition, the circulating effect of flushing liquid in the conventional double-end-face mechanical sealing structure of the slurry pump is not ideal, and the heat dissipation and cooling effects on the sealing surface are poor, so that the service life of the sealing device is influenced; in addition, in the existing double-end-face mechanical sealing structure, the position of a sealing ring between a sealing ring close to a medium end and a sealing seat is easily abraded by solid particles in a medium, so that the service life of the whole mechanical seal is influenced.

Disclosure of Invention

The utility model solves the problem that in order to overcome the defects in the prior art, the double-end mechanical seal is provided, the double-end mechanical seal is simple in structure and short in axial size, flushing liquid in a seal cavity circulates smoothly, the cooling effect on a seal surface is good, and the sealing performance of a sealing device is ensured.

In order to solve the problems, the utility model provides a double-end-face mechanical seal which comprises a shaft sleeve, wherein a seal seat, a main seal assembly and an auxiliary seal assembly are sleeved outside the shaft sleeve, the main seal assembly comprises a driving ring and a main static ring, a first mounting seat is arranged at one end of the shaft sleeve, one end of the driving ring is assembled with the first mounting seat, the other end of the driving ring is in butt fit with one end of the main static ring in a relatively rotating mode, a first static ring groove is arranged at one end of the seal seat, and the other end of the main static ring is sealed and assembled in the first static ring groove in a sliding mode; a first sealing groove is formed in the side wall of the first static ring groove, a sealing ring and a flexible gasket are sequentially assembled in the first sealing groove along the axial direction, the inner ring of the sealing ring is in sealing fit with the outer wall of the main static ring, and the flexible gasket is located on one side far away from the first static ring groove; a conical ring is arranged on the radial inner side of one end, away from the sealing ring, of the flexible gasket, the conical ring extends along the axial direction of the flexible gasket, the diameter of the conical ring is gradually reduced, and the inner wall of the conical ring is attached to the inner wall of the main static ring; one end of the auxiliary sealing assembly is assembled at the other end of the sealing seat, the other end of the shaft sleeve is provided with a second mounting seat, and the other end of the auxiliary sealing assembly is assembled with the second mounting seat; a plurality of threaded holes distributed along the circumferential direction are formed in the end face, far away from one end of the first mounting seat, of the shaft sleeve, a plurality of connecting bolts are arranged on the second mounting seat, and the connecting bolts are connected into the corresponding threaded holes respectively; a sealing cavity is formed among the first mounting seat, the main sealing assembly, the sealing seat, the auxiliary sealing assembly, the second mounting seat and the shaft sleeve, a spiral diversion trench extending along the axial direction is arranged on the outer side wall of the shaft sleeve close to the sealing cavity, and a liquid inlet hole and a liquid outlet hole which are respectively communicated with the sealing cavity are formed in the sealing seat.

Compared with the prior art, the mechanical sealing device has the following advantages:

1. the outer wall of the shaft sleeve, which is close to one side of the sealing cavity, is provided with the spiral diversion trench, and in the process that the shaft sleeve runs along with the rotating shaft, the spiral diversion trench can drive flushing fluid in the sealing cavity to flow and circulate quickly and efficiently, so that the friction heat of a sealing grinding surface and particle impurities can be quickly washed away by the flushing fluid, and the service life of the sealing ring is ensured;

2. the integrated type structure is adopted, and the shaft sleeve, the main sealing assembly, the auxiliary sealing assembly and the sealing seat are pre-installed into an integrated structure before being installed to the pump cavity, so that an installation mode of integral assembly and disassembly is realized, the technical requirement on installation personnel is low, the installation can be quickly and accurately carried out in place, the sealing installation difficulty is reduced, and the failure probability of mechanical sealing caused by installation factors is solved; meanwhile, the sealing maintenance cost is reduced, and the maintenance time is saved;

3. because this mechanical seal device does not need to carry out the transmission through corresponding fastener structure between with rotatory and is connected, compare in traditional mechanical seal device in need increase the transmission seat in the outside of axle sleeve, and be equipped with on the outer wall of transmission seat along radial extension's holding screw, through holding screw tight fit in the pivot, realize that the transmission of a whole set of mechanical seal device and pivot is connected, among the novel mechanical seal device does not need the transmission seat in the axial, only include the size of axle sleeve and second mount pad, effectively shorten mechanical seal's axial dimension, be applicable to the occasion that installation space is little.

4. The sealing ring is arranged in the first static ring groove, a flexible gasket is additionally arranged, the flexible gasket plays a role of preventing the sealing ring from being extruded out of the first sealing groove in the axial direction, and on the other hand, because the sealing position of the main static ring and the sealing seat is directly positioned in a medium, particles in the medium can enter the first sealing ring groove to influence the elastic deformation capacity of the sealing ring, even abrasion of the sealing ring can be caused, and the sealing performance is influenced; the conical inclined plane of the conical ring in the structure well plays a role in guiding, and the situation that particles are close to or stacked at the inner ring position of the flexible gasket is avoided, so that the particles are better prevented from entering the first sealing ring groove.

Furthermore, a first mounting groove is formed in the first mounting seat, and one end of the driving ring is hermetically assembled in the first mounting groove; and a first elastic compensation part for providing elastic compensation for the main static ring is arranged in the first static ring groove. In the structure, the first elastic compensation part is arranged on the side of the main static ring, namely the static ring compensation structure is adopted, and the static ring is static, so that the elastic compensation performance of the elastic compensation part can be more stable, the sealing surface is ensured to be in a wear process, and the main static ring can be always attached to and sealed with the main static ring, so that the sealing performance is ensured.

Still further, the auxiliary sealing assembly comprises an auxiliary rotating ring and an auxiliary static ring, a second mounting groove is formed in the second mounting seat, one end of the auxiliary rotating ring is hermetically and slidably assembled in the second mounting groove, a second static ring groove is formed in the other end of the sealing seat, one end of the auxiliary static ring is hermetically assembled in the second static ring groove, and the other end of the auxiliary static ring is in butt fit with the other end of the auxiliary rotating ring in a relatively rotating mode; and a second elastic compensation part for providing elastic compensation for the auxiliary stationary ring is arranged in the second stationary ring groove. In the structure, the second elastic compensation part is also arranged on the side of the auxiliary static ring, namely, the auxiliary sealing assembly also adopts a static ring compensation type structure, and the static ring is static, so that the elastic compensation performance of the elastic compensation part can be more stable, the sealing surface is ensured to be in a wear process, and the main static ring can be always attached to and sealed with the driving ring, so that the sealing performance is ensured.

Preferably, the first elastic compensation part and the second elastic compensation part each comprise a plurality of elastic parts uniformly distributed along the circumferential direction.

As the improvement, first quiet ring tank bottom portion is equipped with a plurality ofly along the spring hole of circumference distribution and intercommunication to second quiet ring groove, wear to be equipped with long spring in the spring hole, it is a plurality of one end that long spring is located first quiet ring inslot forms first elastic compensation piece, and is a plurality of one end that long spring is located second quiet ring inslot forms second elastic compensation piece. In the above-mentioned improvement structure, lie in on the seal receptacle and be equipped with a plurality of long springs between main quiet ring and the vice quiet ring, the both ends of long spring extend to respectively in first quiet ring groove, the second quiet ring groove in order to form corresponding elastic compensation spare, compare with the conventional elastic compensation spare that sets up alone respectively in first quiet ring groove, the second quiet ring groove and can reduce spare part quantity, simplify mechanical seal's mounting structure. And the disassembly and the assembly are more convenient; in addition, the elastic compensation part formed in the structure can ensure more stability for the elastic compensation force of the main static ring and the auxiliary static ring, and the sealing performance is ensured.

In another improvement, a positioning hole communicated to the second static ring groove is formed in the bottom of the first static ring groove, a positioning pin is assembled in the positioning hole, and two ends of the positioning pin extend towards the main static ring and the auxiliary static ring respectively; the main stationary ring is provided with a first positioning groove matched with one end of the positioning pin, and the auxiliary stationary ring is provided with a second positioning groove matched with the other end of the positioning pin. In the structure, a complete positioning pin is arranged between the first static ring groove and the bottom of the second static ring groove, so that the main static ring and the auxiliary static ring can be positioned in an anti-rotation mode, the whole mechanical sealing structure is simpler, the processing difficulty is reduced, and the disassembly and the assembly are more convenient.

And in the improvement, the structure of the driving ring is the same as that of the auxiliary driving ring, and the structure of the main static ring is the same as that of the auxiliary static ring. The dynamic and static rings at different positions in the improved structure adopt the design of the same structure, so that the driving ring, the auxiliary driving ring, the main static ring and the auxiliary static ring can be replaced, and the installation and the maintenance are more convenient; on the other hand, the moving and static rings with the same structure are beneficial to batch production, and the production cost is reduced.

Drawings

FIG. 1 is a half-section block diagram of a double mechanical seal of the present invention.

Fig. 2 is an enlarged structural view at X in fig. 1.

Fig. 3 is a sectional view of a seal holder according to the present invention.

Fig. 4 is a partial schematic view of a flexible gasket according to the present invention.

Fig. 5 is a sectional view of the sleeve of the present invention.

Fig. 6 is a partial schematic view of a second mounting base in the present invention.

Description of reference numerals:

1. a shaft sleeve; 1.1, a spiral diversion trench; 1.2, a threaded hole; 1.3, mounting a step; 2. a sealing seat; 2.1, liquid inlet holes; 2.2, liquid outlet holes; 2.3, a first static ring groove; 2.3.1, a first sealing groove; 2.4, a second static ring groove; 2.5, spring holes; 3. a first mounting seat; 3.1, a first mounting groove; 4. a second mounting seat; 4.1, a second mounting groove; 5. sealing the cavity; 6. a driving ring; 7. a main stationary ring; 7.1, a first positioning groove; 8. an auxiliary movable ring; 9. a secondary stationary ring; 9.1, a second positioning groove; 10. an elastic member; 11. positioning pins; 12. a seal ring; 13. a flexible gasket; 13.1, a conical ring; 14. and connecting the bolts.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

As shown in fig. 1 and 2, the utility model provides a double-end-face mechanical seal, which comprises a shaft sleeve 1, wherein the shaft sleeve 1 is sleeved outside a rotating shaft, and a seal seat 2, a main seal assembly and an auxiliary seal assembly are sleeved outside the shaft sleeve 1, wherein one end of the shaft sleeve 1 is provided with a first mounting seat 3, one end of the main seal assembly is matched with the first mounting seat 3, and the other end of the main seal assembly is matched with one end of the seal seat 2; one end of the auxiliary sealing assembly is assembled at the other end of the sealing seat 2, the other end of the shaft sleeve 1 is provided with a second mounting seat 4, the other end of the auxiliary sealing assembly is assembled with the second mounting seat 4, the second mounting seat 4 is detachably connected with the shaft sleeve 1, the first mounting seat 3, the main sealing assembly, the sealing seat 2, the auxiliary sealing assembly and the shaft sleeve 1 form a sealing cavity 5 therebetween, concretely, a spiral diversion trench 1.1 extending along the axial direction is arranged on the outer side wall of the shaft sleeve 1 close to the sealing cavity 5, a liquid inlet hole 2.1 and a liquid outlet hole 2.2 communicated with the sealing cavity 5 are arranged on the sealing seat 2, in the structure, in order to prevent dust or impurities from entering the sealing cavity 5, a corresponding rubber plug is arranged in the liquid inlet hole 2.1 and the liquid outlet hole 2.2, the rubber plug needs to be pulled out during actual use, and a water inlet pipe and a water outlet pipe are installed. In the structure, the first mounting seat 3 and the shaft sleeve 1 are of an integral structure, namely, the integral stainless steel material is machined and formed, subsequent mounting is not needed, the structure is simple, and the machining is convenient. In addition, the second mounting seat 4 and the shaft sleeve 1 are detachably mounted, and the structure is mainly used for facilitating the pre-mounting of the whole mechanical sealing device.

Specifically, a plurality of threaded holes 1.2 distributed along the circumferential direction are formed in the end face, away from one end of the first mounting seat 3, of the shaft sleeve 1, a plurality of connecting bolts 14 distributed along the circumferential direction are arranged on the second mounting seat 4, and the connecting bolts 14 are connected in the corresponding threaded holes 1.2. More specifically, the outside of keeping away from 3 one ends of first mount pad at axle sleeve 1 is equipped with installation step 1.3, be equipped with third mounting groove 4.2 in the inboard of second mount pad 4, during the installation, second mount pad 4 suit is on axle sleeve 1, make third mounting groove 4.2 and installation step 1.3 cooperate, and the bottom of third mounting groove 4.2 and the tip looks butt of axle sleeve 1, connecting bolt 14 wears to establish the bottom at third installation 4.2, and be equipped with O type circle between mount table 1.2 and third mounting groove 4.2 lateral wall, in order to realize sealed cooperation. After the second mounting seat 4 and the shaft sleeve 1 are arranged in the mounting mode, the axial size of the whole mechanical sealing device can be further shortened, and the mounting space of a pump cavity is saved.

In this embodiment, the mechanical seal with the above structure is installed in a clamping manner with the driving of the rotating shaft in practical application, and when the whole sealing device is sleeved on the rotating shaft, the front end and the rear end of the mechanical seal are clamped and positioned by the corresponding clamping blocks, so that the shaft sleeve 1 in the mechanical seal is driven to be in transmission connection with the rotating shaft.

Specifically, in the above structure, the main sealing assembly includes a driving ring 6 and a main stationary ring 7, the first mounting seat 3 is provided with a first mounting groove 3.1, one end of the driving ring 6 is hermetically assembled in the first mounting groove 3.1, that is, a corresponding O-ring is arranged between the driving ring 6 and the first mounting groove 3.1 to realize sealed mounting; one end of the sealing seat 2 is provided with a first static ring groove 2.3, one end of a main static ring 7 is sealed and can be assembled in the first static ring groove 2.3 in a sliding way, and the other end of the main static ring 7 is in butt fit with the other end of the driving ring 6 in a relatively rotating way so as to form a main sealing grinding surface; a first elastic compensation part for providing elastic compensation for the main static ring is arranged in the first static ring groove 2.3; the first elastic compensation part can compensate the axial abrasion loss in time after the main seal grinding surface is abraded, so that the driving ring 6 and the main static ring 7 are always tightly attached, and the sealing performance is effectively guaranteed.

Similarly, the auxiliary sealing assembly comprises an auxiliary moving ring 8 and an auxiliary static ring 9, a second mounting groove 4.1 is formed in the second mounting seat 4, one end of the auxiliary moving ring 8 is hermetically assembled in the second mounting groove 4.1, namely, a corresponding O-shaped ring is arranged between the second mounting groove 4.1 and the auxiliary moving ring for sealing; the other end of the sealing seat 2 is provided with a second static ring groove 2.4, one end of an auxiliary static ring 9 is hermetically and slidably assembled in the second static ring groove 2.4, the side wall of the second static ring groove 2.4 is provided with a containing groove, an O-shaped ring is assembled in the containing groove, and the inner wall of the O-shaped ring is hermetically matched on the outer wall of the auxiliary static ring 9, so that the sealing connection between the auxiliary static ring 9 and the sealing seat 2 is realized; the other end of the auxiliary static ring 9 and the other end of the auxiliary dynamic ring 8 can be in relatively rotating butt fit to form an auxiliary sealing grinding surface; be equipped with in the second quiet annular 2.4 and be used for providing the second elastic compensation piece of elastic compensation for vice quiet ring 9, the compensation that can in time carry out the axial wear volume to vice sealed wearing and tearing back is realized to the second elastic compensation piece, makes vice rotating ring 8 and vice quiet ring 9 keep closely laminating throughout, guarantees sealing performance.

Specifically, when the container type structure is installed, the driving ring 6 is installed in the first installation groove 3.1, the main static ring 7 is installed in the first static ring groove 2.3, and then the sealing seat 2 provided with the main static ring 7 is sleeved on the shaft sleeve 1 to ensure that the main static ring 7 is attached to the driving ring 6; then, an auxiliary stationary ring 9 is installed in a second stationary ring seat 2.4 of the sealing seat 2, the second installation seat 4 pre-installed with the auxiliary moving ring 8 is sleeved on the shaft sleeve 1 after the second installation seat is made to fit with the auxiliary stationary ring 9, the second installation seat 4 is fixedly connected with the shaft sleeve 1 through a connecting bolt 14, and therefore the shaft sleeve 1, the main sealing assembly, the auxiliary sealing assembly and the sealing seat 2 are made to be of an integral structure in a pre-installation mode, and the whole installation and the whole disassembly can be achieved during the installation, and the installation is very convenient.

In this embodiment, the first elastic compensation element and the second elastic compensation element each include a plurality of elastic elements 10 uniformly distributed along the circumferential direction, and in this structure, the elastic elements 10 are preferably cylindrical small springs, and the plurality of cylindrical small springs are circumferentially arranged to stabilize the elastic compensation force. On the other hand, a plurality of spring holes 2.5 distributed along the circumferential direction and communicated to the second static ring groove 2.4 are formed in the bottom of the first static ring groove 2.3, long springs penetrate through the spring holes 2.5, a first elastic compensation part is formed at one end, located in the first static ring groove 2.3, of each of the long springs, and a second elastic compensation part is formed at one end, located in the second static ring groove 2.4, of each of the long springs. In the above-mentioned structure, main seal assembly and vice seal assembly are quiet ring compensation formula structure, and elastic compensation spare all sets up between quiet ring and the corresponding mounting groove of seal receptacle 2 promptly, and quiet ring compensation form structure makes elastic compensation spare not receive pivot pivoted influence, guarantees the stability of elastic compensation power, and then guarantees the leakproofness of the sealed mill flour that corresponds.

As shown in fig. 3, a positioning hole communicated to the second static ring groove 2.4 is formed at the bottom of the first static ring groove 2.3, a positioning pin 11 is assembled in the positioning hole, and two ends of the positioning pin 11 extend towards the main static ring 7 and the auxiliary static ring 9 respectively; the main stationary ring 7 is provided with a first positioning groove 7.1 matched with one end of the positioning pin 11, and the auxiliary stationary ring 9 is provided with a second positioning groove 9.1 matched with the other end of the positioning pin 11. In the structure, the anti-rotation positioning of the main static ring 7 and the auxiliary static ring 9 can be realized simultaneously through a complete positioning pin 11, the structure is simplified, and the stability is ensured.

As shown in fig. 2-4, a first seal groove 2.3.1 is provided on the sidewall of the first stationary ring groove 2.3, a seal ring 12 and a flexible gasket 13 are sequentially assembled in the first seal groove 2.3.1 along the axial direction, the inner ring of the seal ring 12 is in sealing fit with the outer wall of the main stationary ring 7, and the flexible gasket 13 is located on the side away from the first stationary ring groove 2.3; the radial inboard that flexible gasket 13 kept away from sealing washer 12 one end is equipped with conical ring 13.1, and conical ring 13.1 extends and the diameter reduces gradually along flexible gasket 13's axial, and conical ring 13.1's inner wall is laminated with the inner wall of main quiet ring 7 mutually.

On the other hand, in the present embodiment, the driving ring 6 and the auxiliary driving ring 8 are the same in structure and are made of cemented carbide, and the main stationary ring 7 and the auxiliary stationary ring 9 are the same in structure and are made of silicon carbide. After the arrangement, the replacement between the driving ring 6 and the auxiliary driving ring 8 can be realized, and the replacement between the main static ring 7 and the auxiliary static ring 9 can also be realized; on the other hand, the method is convenient for batch production and improves the production efficiency.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and such changes and modifications will fall within the scope of the present invention.

Claims

1. The utility model provides a double mechanical seal, includes axle sleeve (1), axle sleeve (1) outside cover is equipped with seal receptacle (2), main seal assembly and vice seal assembly, its characterized in that: the main sealing assembly comprises a driving ring (6) and a main static ring (7), a first mounting seat (3) is arranged at one end of the shaft sleeve (1), one end of the driving ring (6) is assembled with the first mounting seat (3), the other end of the driving ring (6) is in butt fit with one end of the main static ring (7) in a relatively rotating mode, a first static ring groove (2.3) is arranged at one end of the sealing seat (2), and the other end of the main static ring (7) is sealed and assembled in the first static ring groove (2.3) in a sliding mode; a first sealing groove (2.3.1) is arranged on the side wall of the first static ring groove (2.3), a sealing ring (12) and a flexible gasket (13) are sequentially assembled in the first sealing groove (2.3.1) along the axial direction, the inner ring of the sealing ring (12) is in sealing fit with the outer wall of the main static ring (7), and the flexible gasket (13) is positioned on one side far away from the first static ring groove (2.3); a conical ring (13.1) is arranged on the radial inner side of one end, away from the sealing ring (12), of the flexible gasket (13), the conical ring (13.1) extends along the axial direction of the flexible gasket (13) and is gradually reduced in diameter, and the inner wall of the conical ring (13.1) is attached to the inner wall of the main static ring (7); one end of the auxiliary sealing assembly is assembled at the other end of the sealing seat (2), the other end of the shaft sleeve (1) is provided with a second mounting seat (4), and the other end of the auxiliary sealing assembly is assembled with the second mounting seat (4); a plurality of threaded holes (1.2) distributed along the circumferential direction are formed in the end face of one end, away from the first mounting seat (3), of the shaft sleeve (1), a plurality of connecting bolts (14) are arranged on the second mounting seat (4), and the plurality of connecting bolts (14) are respectively connected into the corresponding threaded holes (1.2); form sealed chamber (5) between first mount pad (3), main seal assembly, seal receptacle (2), vice seal assembly, second mount pad (4) and axle sleeve (1), be equipped with on the lateral wall of the nearly sealed chamber (5) of axle sleeve (1) along axially extending spiral guiding gutter (1.1), be equipped with respectively on seal receptacle (2) with feed liquor hole (2.1) and play liquid hole (2.2) of sealed chamber (5) intercommunication.

2. The double mechanical seal of claim 1, wherein: a first mounting groove (3.1) is formed in the first mounting seat (3), and one end of the driving ring (6) is hermetically assembled in the first mounting groove (3.1); a first elastic compensation part for providing elastic compensation for the main static ring (7) is arranged in the first static ring groove (2.3).

3. The double mechanical seal of claim 2, wherein: the auxiliary sealing assembly comprises an auxiliary moving ring (8) and an auxiliary static ring (9), a second mounting groove (4.1) is formed in the second mounting seat (4), one end of the auxiliary moving ring (8) is hermetically assembled in the second mounting groove (4.1), a second static ring groove (2.4) is formed in the other end of the sealing seat (2), one end of the auxiliary static ring (9) is hermetically and slidably assembled in the second static ring groove (2.4), and the other end of the auxiliary static ring (9) is in butt fit with the other end of the auxiliary moving ring (8) in a relatively rotatable manner; and a second elastic compensation part for providing elastic compensation for the auxiliary static ring (9) is arranged in the second static ring groove (2.4).

4. A double mechanical seal according to claim 3 wherein: the first elastic compensation part and the second elastic compensation part respectively comprise a plurality of elastic parts (10) which are uniformly distributed along the circumferential direction.

5. The double mechanical seal of claim 4, wherein: the bottom of the first static ring groove (2.3) is provided with a plurality of spring holes (2.5) which are distributed along the circumferential direction and communicated to the second static ring groove (2.4), long springs are arranged in the spring holes (2.5) in a penetrating mode, the long springs are arranged at one ends of the first static ring groove (2.3) in a plurality of mode to form first elastic compensation parts, and the long springs are arranged at one ends of the second static ring groove (2.4) in a plurality of mode to form second elastic compensation parts.

6. A double mechanical seal according to claim 4 or 5, wherein: a positioning hole communicated to the second static ring groove (2.4) is formed in the bottom of the first static ring groove (2.3), a positioning pin (11) is assembled in the positioning hole, and two ends of the positioning pin (11) extend towards the main static ring (7) and the auxiliary static ring (9) respectively; the main stationary ring (7) is provided with a first positioning groove (7.1) matched with one end of the positioning pin (11), and the auxiliary stationary ring (9) is provided with a second positioning groove (9.1) matched with the other end of the positioning pin (11).

7. A double mechanical seal according to any one of claims 3 to 5 wherein: the driving ring (6) and the auxiliary driving ring (8) are identical in structure, and the main static ring (7) and the auxiliary static ring (9) are identical in structure.