Sliding ring seal assembly with anti-return device

Description

[0001] The present invention relates to a mechanical seal arrangement with a disengagement device for the rotating sliding ring, particularly when used with contaminated media.

[0002] Mechanical seal assemblies are known in various configurations from the prior art. To prevent a sliding ring from disengaging, it is typically shrunk onto a sleeve or similar component. This creates a force-fit connection between the sliding ring and the sleeve, preventing axial movement and disengagement of the sliding ring. Particularly when sealing contaminated media, such as petroleum, sliding rings with a diamond coating are often used. However, due to the coating, such a sliding ring cannot be shrunk onto a sleeve or similar component. Diamond-coated sliding rings offer the advantage of a longer service life, especially when used with contaminated media. Therefore, such sliding rings must be arranged loosely, i.e., movable in the axial direction of the mechanical seal assembly.However, due to its use with contaminated media, it is possible that dirt particles from the medium may enter a gap on the rotating sliding ring and cause misalignment or warping of the sliding surface. Furthermore, EP 0 035 092 A1 discloses a mechanical seal arrangement according to the preamble of claim 1. US 3,356,378 B discloses a mechanical seal which can prevent rotation of the sliding rings in the circumferential direction.

[0003] It is therefore an object of the present invention to provide a mechanical seal arrangement which, with a simple design and simple, cost-effective manufacturing capability, has a loosely inserted sliding ring which enables reliable axial repositioning and can be used without problems in contaminated media.

[0004] This problem is solved by a mechanical seal arrangement having the features of claim 1, the dependent claims showing preferred embodiments of the invention.

[0005] The mechanical seal assembly according to the invention, comprising the features of claim 1, has a rotating and a stationary sliding ring, which define a sealing gap between them. Furthermore, a bellows element is provided, which allows the rotating sliding ring to move axially within the mechanical seal. A disengagement device prevents axial disengagement of the rotating sliding ring. The disengagement device comprises an inner sleeve with a radially outwardly directed rib. A radially inwardly directed shoulder with a contact surface is provided on the sliding ring. The rotating sliding ring is freely movable in the axial direction and loosely arranged on the inner sleeve. This eliminates the need for shrink-fitting the rotating sliding ring. The disengagement device prevents unwanted disengagement of the rotating sliding ring during axial movement within the seal.Since no shrinkage process is necessary to fix the rotating sliding ring, the rotating sliding ring can have a diamond coating or another type of coating. Furthermore, the anti-disengagement device is located on an inner area of ​​the mechanical seal assembly where it does not come into contact with the contaminated medium. This ensures a high level of operational reliability for the mechanical seal assembly according to the invention. A clean barrier medium or similar substance is present at the inner sleeve, and the ingress of contaminants between the sliding ring and the inner sleeve is prevented. As a result, no warping or other damage to the sliding ring occurs during operation due to the contaminated medium. Furthermore, non-destructive disassembly of the rotating sliding ring is possible because there is no shrinkage or similar process on a sleeve.

[0006] Furthermore, an outer sleeve is provided, which is connected to the inner sleeve. This makes it possible to transmit torque from a rotating component, e.g., a shaft, via the bellows element and the outer sleeve to the rotating sliding ring. For torque transmission between the outer sleeve and the rotating sliding ring, preferably one or more pins, in particular cylindrical pins, are provided.

[0007] Preferably, the outwardly facing rib of the inner sleeve is in direct contact with the contact surface on the rotating sliding ring. This ensures reliable axial movement of the rotating sliding ring. Furthermore, the direct contact prevents unwanted disengagement of the rotating sliding ring.

[0008] The contact surface on the rotating sliding ring is preferably aligned perpendicular to the axial direction. This ensures a simple design.

[0009] According to a further preferred embodiment of the present invention, the mechanical seal assembly comprises a spring element arranged between the web of the inner sleeve and the contact surface of the rotating sliding ring. The spring element provides a spring force in the axial direction and ensures a backlash-free connection between the inner sleeve and the rotating sliding ring. The spring element is preferably a wave spring.

[0010] A welded connection between the outer sleeve and the inner sleeve is also preferably provided.

[0011] According to an alternative embodiment of the present invention, a snap-fit ​​connection is provided between the outer sleeve and the inner sleeve. Preferably, two locking lugs are formed on the outer sleeve, which engage in corresponding recesses in the inner sleeve. This makes it possible to separate the outer sleeve and the inner sleeve from each other without damage and also to remove the rotating sliding ring without damage.

[0012] For a particularly compact design, the bellows element is preferably firmly connected to the outer sleeve.

[0013] According to a further preferred embodiment of the present invention, the outer sleeve partially overlaps the rotating sliding ring. This protects the end of the rotating sliding ring facing away from the sealing gap from the contaminated medium. A secondary sealing element, particularly an O-ring, is preferably arranged between the outer sleeve and the rotating sliding ring. The secondary sealing element is particularly preferably arranged in a groove in the outer sleeve, the groove being formed on an inner circumferential region of the outer sleeve that faces the rotating sliding ring.

[0014] Preferably, a contact seal is provided between the outer sleeve and the rotating sliding ring. The contact seal is preferably located at an end of the rotating sliding ring and the outer sleeve facing away from the sealing gap.

[0015] The rotating sliding ring preferably has a diamond coating. This makes it possible to use a diamond-coated, rotating sliding ring which is arranged in the mechanical seal assembly without force and, in particular, can be adjusted axially. Furthermore, the rotating sliding ring can be disassembled non-destructively. This means that only the rotating sliding ring needs to be replaced, and the remaining components of the mechanical seal assembly, especially the bellows element, can be reused.

[0016] A mechanical seal assembly according to preferred embodiments of the invention is described in detail below with reference to the accompanying drawing. In the drawing, identical or functionally equivalent parts are designated with the same reference numerals. The drawing shows: Fig. 1 is a schematic sectional view of a mechanical seal arrangement according to a first preferred embodiment of the invention, Fig. 2 is a schematic sectional view of a mechanical seal arrangement according to a second preferred embodiment of the invention, and Fig. 3 is an enlarged partial sectional view of the Fig. 2 shown release mechanism.

[0017] The following refers to Fig. 1 A mechanical seal arrangement 1 according to a first embodiment of the invention is described in detail.

[0018] As from Fig. 1 As can be seen, the mechanical seal arrangement 1 comprises a rotating sliding ring 2 and a stationary sliding ring 3, which define a sealing gap 4 between them.

[0019] The stationary sliding ring 3 is fixed to a stationary component 30, e.g. a housing or the like.

[0020] The mechanical seal arrangement 1 is designed to seal an area 12 on a rotating component 14, e.g. a shaft, in which a dirty medium is present, against an inner area 13 with a sealing medium, e.g. a barrier fluid, such as oil or the like.

[0021] In order to be able to perform axial compensating movements with the rotating component 14, a bellows element 10 is also provided, which is firmly connected to the rotating component 14 via a multi-part bellows fixing unit 11 (see figure). Fig. 1 This allows axial movements of the shaft to be compensated for by the bellows element 10. The bellows element 10 is preferably made of metal.

[0022] In order to prevent the rotating sliding ring 2 from disengaging during such axial movements, especially during a back-and-forth movement in the axial direction XX, a disengagement protection device 5 is provided according to the invention.

[0023] The release mechanism 5 comprises an inner sleeve 6 and an outer sleeve 7.

[0024] The rotating sliding ring 2 is loosely inserted between the inner sleeve 6 and the outer sleeve 7. The inner sleeve 6 is arranged on an inner circumferential region of the rotating sliding ring 2, and the outer sleeve 7 is arranged on an outer circumferential region of the rotating sliding ring 2. The outer sleeve 7 overlaps an outer lateral region of the rotating sliding ring 2.

[0025] For torque transmission, several cylindrical pins 9 are provided, which are inserted into corresponding recesses in the rotating sliding ring 2 and are fixed to the outer sleeve 7 with an interference fit. This allows rotation of the rotating component 14 to be transmitted via the multi-part bellows fixing unit 11 and the bellows element 10 to the outer sleeve 7 and from the outer sleeve 7 to the rotating sliding ring 2.

[0026] A secondary seal 8 in the form of an O-ring is further arranged between the outer sleeve 7 and the rotating sliding ring 2. For this purpose, a correspondingly shaped recess 71 is provided in the outer sleeve 7.

[0027] The bellows element 10 is firmly connected to the outer sleeve 7, for example by means of a welded connection.

[0028] Furthermore, the outer sleeve 7 and the inner sleeve 6 are also firmly connected to each other. Preferably, a welded connection 18 is also provided here.

[0029] What's next? Fig. 1 As can be seen, a web 60 is provided on the inner sleeve 6, which is arranged at the end of the inner sleeve 6 facing the sealing gap 4. The web 60 is an annular circumferential web which bears against a contact surface 21 of the rotating sliding ring 2. The contact surface 21 is formed on a shoulder 20 of the rotating sliding ring 2. This results in a contact area 23 between the web 60 and the contact surface 21 that is perpendicular to the axial direction XX. The contact area 23 between the web 60 and the contact surface 21 thus extends in the radial direction of the mechanical seal assembly. Furthermore, the inner sleeve 6 has several openings 61 on an inner circumferential region to supply sealing medium from the inner region 13 to the inner region 101 of the bellows element 10.

[0030] In contrast to the prior art, in which the rotating sliding ring 2 is fixed to a sleeve by means of a shrink-fit connection, in the present invention the rotating sliding ring 2 is arranged without force between the inner sleeve 6 and the outer sleeve 7. The rotating sliding ring 2 is thus loosely placed onto the inner sleeve 6 before assembly, and the outer sleeve 7 is then firmly connected to the inner sleeve 6, e.g., via the weld 18. The provision of the web 60 on the inner sleeve 6 prevents the rotating sliding ring 2 from disengaging from the connection between the inner sleeve 6 and the outer sleeve 7. This makes it particularly possible to apply a coating, especially a diamond coating, to a sliding surface 22 of the rotating sliding ring 2.

[0031] Since the disengagement device 5 is essentially located on an inner circumference of the rotating sliding ring 2, the mechanical seal assembly 1 can be used particularly well with contaminated media, e.g., in rotating components during oil production. In particular, it prevents particles from the conveyed medium from reaching the contact area 23 between the web 60 and the contact surface 21 in area 12 and causing misalignment of the rotating sliding ring 2 from its axially oriented position. Such misalignments could lead to undesirable wear or contact between the rotating sliding ring 2 and the stationary sliding ring 3 in the area of ​​the sealing gap 4. Furthermore, the rotating sliding ring 2 can be disassembled and replaced without damage.For this purpose, the fixed connection between the inner sleeve 6 and the outer sleeve 7 must be removed, but the loosely inserted sliding ring can simply be removed and a new rotating sliding ring 2 can be arranged on the release device 5 without tension.

[0032] Furthermore, by providing the contact area 23 between the bridge 60 and the contact surface 21 perpendicular to the axial direction XX, jamming of the components can be prevented.

[0033] Furthermore, the mechanical seal arrangement according to the invention can also be used for processes with pressure reversal.

[0034] The Fig. 2 and 3 show a mechanical seal arrangement 1 according to a second embodiment of the invention.

[0035] In contrast to the first embodiment, the second embodiment provides a release device 5 in which a non-destructive, releasable connection is provided between the inner sleeve 6 and the outer sleeve 7.

[0036] In this embodiment, a snap-fit ​​connection 16 is provided between the inner sleeve 6 and the outer sleeve 7. The inner sleeve 6 comprises snap-fit ​​lugs 62 which engage in correspondingly complementary snap-fit ​​recesses 70 in the outer sleeve 7. This is shown in detail in the figure below. Fig. 3 The locking connection 16 is thus formed at the end of the inner sleeve 6 facing away from the sealing gap 4. Preferably, a circumferential locking lug 62 and a corresponding circumferential locking recess 70 are provided.

[0037] Furthermore, in contrast to the first embodiment, a wave spring 15 is provided between the web 60 and the contact surface 21 of the rotating sliding ring 2. The wave spring exerts a force in the axial direction XX. The wave spring 15 is corrugated in the circumferential direction and alternately bears against the web 60 and the contact surface 21. Thus, the axial force applied by the wave spring 15 is essentially evenly distributed in the circumferential direction.

[0038] Furthermore, instead of the elastomer seal in the form of the secondary seal 8 used in the first embodiment, a contact seal 17 is provided between the outer sleeve 7 and the rotating sliding ring 2 in the second embodiment. This makes it possible, in particular, for the sliding ring seal 1 of the second embodiment to be very compact in the radial direction, i.e., perpendicular to the axial direction XX. Reference symbol list

[0039] 1 Mechanical seal assembly 2 Rotating sliding ring 3 Stationary sliding ring 4 Sealing gap 5 Disengagement device 6 Inner sleeve 7 Outer sleeve 8 Secondary seal 9 Cylindrical pin 10 Bellows element 11 Bellows fixing unit 12 Area 13 Inner area 14 Rotating component 15 Spring element, wave spring 16 Detent connection 17 Contact seal 18 Welded connection 20 Step 21 Contact surface 22 Sliding surface 23 Contact area 30 Housing 60 Web 61 Opening in axial direction 62 Detent lug 70 Detent recess 71 Recess 101 Inner area X-X Axial direction

Claims

1. Mechanical seal arrangement, comprising: - a rotating slide ring (2) and a stationary slide ring (3), which delimit a sealing gap (4) in between them, - wherein the rotating slide ring (2) has a radially inward facing ledge (20) with a contact surface (21), - a bellows element (10) for refitting the rotating slide ring (2) in an axial direction (X-X) of the mechanical seal arrangement, and - a release protection device (5) for the rotating slide ring (2), - wherein the release protection device (5) comprises an inner sleeve (6) with a radially outward facing web (60), which restricts a movement of the rotating slide ring (2) in the axial direction (X-X), and - wherein the rotating slide ring (2) is arranged on the inner sleeve (6) so as to be freely movable in the axial direction (X-X) - further comprising an outer sleeve (7) that is connected to the inner sleeve (6), - characterized in that the rotating slide ring (2) is inserted loosely between the inner sleeve (6) and the outer sleeve (7).

2. Arrangement according to claim 1, wherein the outward facing web (60) is in direct contact with the contact surface (21) of the rotating slide ring (2).

3. Arrangement according to claim 1, wherein a spring element (15) is arranged between the web (60) and the contact surface (21) of the rotating slide ring (2).

4. Arrangement according to one of the preceding claims, wherein the contact surface (21) is aligned to be perpendicular to the axial direction (X-X).

5. Arrangement according to one of the preceding claims, wherein a connection between the outer sleeve (7) and the inner sleeve (6) is provided as a welded connection (18).

6. Arrangement according to one of the preceding claims, wherein a connection between the outer sleeve (7) and the inner sleeve (6) is embodied as a snap-in connection (16).

7. Arrangement according to one of the preceding claims, further comprising a pin (9) for transferring a torque from the outer sleeve (7) to the rotating slide ring (2).

8. Arrangement according to one of the preceding claims, wherein the bellows element (10) is fixedly connected to the outer sleeve (7).

9. Arrangement according to one of the preceding claims, wherein a contact seal (17) is provided between the outer sleeve (7) and the rotating slide ring (2).

10. Arrangement according to one of the preceding claims, wherein a slide surface (22) of the rotating slide ring (2) has a diamond coating.