LIP SEAL WITH MOVABLE AND FIXED LIP

Description

[0001] The present invention relates to a lip seal having two lips, namely a first rigid lip and a second movable, flexible lip, and in particular to an agitator lip seal or a lip seal for conveyor screws or the like.

[0002] Lip seals are known in various designs from the prior art. One application for lip seals is, for example, the sealing of agitator shafts, where the agitator shaft is usually arranged vertically. Lip seals are often arranged on a shaft in conjunction with several circular seals connected in series. Lip seals are usually made of a flexible material and have a tapered lip end region that rests on a shaft or the like to be sealed. For example, DE 20 2009 013 547 U1 discloses a shaft feedthrough with a throttle and wiper arrangement upstream of an actual sealing arrangement. A lip of the wiper arrangement is arranged contactlessly on a rotating component and serves to repel particles and protect the downstream sealing arrangement.However, this arrangement requires a relatively large overall length in the axial direction of the shaft to be sealed. Furthermore, US 2012 / 0 169 014 A1 discloses a lip seal with an elastomer sealing lip and a PTFE sealing lip, which cannot compensate for radial movements, according to the preamble of claim 1.

[0003] It is an object of the present invention to provide a lip seal which, with a simple structure and simple, cost-effective manufacture, can also provide a seal itself, so that subsequently no or only a very small number of additional seals are necessary for sealing on the shaft.

[0004] This object is achieved by a lip seal having the features of claim 1. The subclaims show preferred developments of the invention.

[0005] The lip seal according to the invention with the features of claim 1 has the advantage that the lip seal itself can provide a very good sealing effect on a rotating component, such as a shaft or a shaft sleeve. The lip seal has a very simple and cost-effective design. In particular, the lip seal is suitable for sealing agitator shafts of agitators in the chemical industry or the food industry or the like. The lip seal for sealing on a rotating component comprises a base part, a movable, flexible second lip, and a support body. The base part comprises a main body and a rigid, non-rotating first lip, which is formed integrally with the main body. The movable lip has a holding region and a movable lip region. The support body is firmly connected to the base part.The movable lip is firmly clamped at its holding area between the base part and the support body. A movement space is also formed on the movable lip to allow for movement of the movable lip. This makes it particularly possible to compensate for temperature-related length changes in the components. Furthermore, the movement space ensures a defined mobility of the movable lip on the rotating component to be sealed, which can compensate for minor deflections of the rotating component.

[0006] The lip seal further comprises a housing with a receiving space in which the base part and the support body, as well as the movable lip, are at least partially accommodated. Radially outside the base part, a compensation space is provided between the base part and the housing for radial movement of the base part into the compensation space. The housing is preferably constructed in two parts, which significantly simplifies assembly of the lip seal.

[0007] In order to be able to compensate in particular for radial deflections of the rotating component, the movement space is preferably formed between the movable lip and the rigid lip of the base part.

[0008] The movement space at the movable lip preferably allows movement of the movable lip in both the radial and axial directions. This allows radial and / or axial deflections of the rotating component to be compensated.

[0009] Further preferably, the movable lip is made of a flexible material, in particular a highly flexible material containing PTFE (polytetrafluoroethylene). The base part and the support body are preferably made of an inflexible, hard material, in particular a metal material.

[0010] The base part preferably further comprises a receiving area for the movable lip and the support body, which is arranged on the main body of the base part. This allows for a very compact and space-saving design.

[0011] Further preferably, the support body has an arcuate region against which the movable lip rests. The movable lip can thus rest against the arcuate region of the support body according to the design of the arcuate region, thereby improving the sealing function.

[0012] More preferably, the lip seal further comprises a shaft sleeve, wherein the fixed lip contacts the shaft sleeve at a contact area in a manner that does not completely seal. Thus, the rigid lip and the shaft sleeve are in contact with each other, but in such a way that a complete sealing effect is not achieved. Rather, solids in the medium to be sealed, or the like, can be kept away from the lip seal, and only minimal leakage of gas or liquid passes through the rigid lip of the base part to the movable lip.

[0013] The shaft sleeve particularly preferably has a coating in the contact area. This reduces the frictional resistance of the rigid lip against the shaft sleeve. Particularly preferably, a recess is formed in the shaft sleeve, which is then filled with a material of the coating. Alternatively or additionally, the rigid lip of the base part has a coating. This can reduce the coefficient of friction between the rigid lip and the rotating component, in particular the shaft sleeve.

[0014] To improve the sealing effect of the lip seal, the support body preferably has a labyrinth seal on a radial inner side. Thus, the lip seal according to the invention comprises at least three sealing areas in series, namely the first rigid lip, the second movable lip, and the labyrinth seal.

[0015] For even better sealing, the support body includes a sliding sleeve on its radial inner side. The sliding sleeve is in contact with the rotating component and is preferably made of PTFE. Particularly preferably, a coating is provided in the area of ​​the sliding sleeve on the rotating component. The sliding sleeve provides a fourth sealing area.

[0016] Preferably, the support body and the base part are firmly connected to each other. The connection between the support body and the base part is preferably a clamp connection. Alternatively, a screw connection or a connection by means of press pins is provided between the support body and the base part.

[0017] Further preferably, a first, disc-shaped sealing element is arranged between the housing and the base part. Furthermore, a second disc-shaped sealing element is arranged between the housing and the support body. The first and second sealing elements are preferably PTFE discs.

[0018] Particularly preferably, the movable lip has a plurality of grooves in the movable lip region on a radially inwardly directed side. The grooves preferably run parallel to one another in the axial direction of the lip seal.

[0019] According to a further preferred embodiment of the invention, the lip seal has a flushing feature. Preferably, a first channel is formed in the base part, which runs through the main body and the rigid lip. The first channel opens into the movement space between the movable lip and the rigid lip. Further preferably, a second channel is formed in the support body, which runs from an outer side of the support body to a radial inner side of the support body.

[0020] For supplying a barrier fluid, the base part preferably has a supply channel on a rear side which is connected to the first and second channels.

[0021] In order to accommodate temperature-related radial length changes of the movable lip, a radial compensation space is preferably provided at one end of the retaining area of ​​the movable lip. This ensures that radial expansion of the movable lip is possible even during temperature changes, so that the sealing effect of the movable lip is not impaired by changing ambient temperatures or changing temperatures of the medium to be sealed.

[0022] Furthermore, the invention relates to a sealing arrangement comprising a lip seal according to the invention and an additional seal, in particular a mechanical seal, connected in series with the lip seal. Since the lip seal itself has a sealing effect, it is possible to achieve sufficient sealing on a rotating component, in particular an agitator shaft, with just a single additional seal connected in series.

[0023] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings. In the drawing: Fig. 1 is a schematic partial sectional view of a lip seal according to a first embodiment of the invention, and Fig. 2 is a schematic partial sectional view of a lip seal according to a second embodiment of the invention.

[0024] The following is based on reference to Fig. 1a lip seal 1 according to a first preferred embodiment of the invention is described in detail.

[0025] The lip seal 1 seals a product area 17 from a downstream area 18, for example an atmospheric area. As can be seen from Fig. 1 As can be seen, the lip seal 1 comprises a hard base part 2 with a main body 20 and a rigid, inflexible lip 21 arranged integrally thereon. The lip 21 has a tapered end.

[0026] The tapered end is in contact with a rotating component, in this embodiment a shaft sleeve 6. As can be seen from Fig. 1 As can be seen, a coating 61 is provided on the shaft sleeve 6, which fills a recess 63 located in an outer circumference of the shaft.

[0027] The rigid lip 21 of the base part 2 rests on the shaft sleeve 6 in the region of the coating 61 at a first contact area 60 in a not completely sealing manner.

[0028] The lip seal 1 further comprises a second movable lip 3, which is made, for example, of PTFE. The movable lip 3 comprises a holding portion 30 and a movable lip portion 31. The holding portion 30 is arranged in the radial direction R, and the movable lip portion 31 contacts the surface of the rotating component at a second contact portion 62.

[0029] The lip seal 1 further comprises a hard support body 4, which is firmly connected to the base part 2. In this embodiment, a clamping connection 16 is formed between the support body 4 and the base part 2.

[0030] The movable lip 3 is firmly clamped at the holding area 30 between the base part 2 and the support body 4. A first radial compensation chamber 10 is formed radially outside the holding area 30.

[0031] Furthermore, a movement space 5 is formed on the movable lip 3. As can be seen from Fig. 1 As can be seen, the movement space 5 is provided between the movable lip 3 and the rigid lip 21. The movable lip 3 can move both in the axial direction XX and in the radial direction R. This allows, in particular, temperature-related length changes of the movable lip 3 and other components to be compensated. The movable lip 3, made of PTFE, is very flexible. As can be seen from Fig. 1As can be seen, the movable lip 3 has a constant thickness. Furthermore, a tapered end is formed on the movable lip 3. The movable lip 3 is in direct contact with the coating 61 of the shaft sleeve 6 at the second contact area 62, thus forming a seal.

[0032] How to continue Fig. 1 As can be seen, the movable lip 3 and the support body 4 are arranged in a receiving area 22 of the base part 2. A rear side of the support body 4 is flush with the main body 20 of the base part 2.

[0033] The support body 4 has an arcuate region 40 against which the movable lip 3 rests. As a result, the movable lip 3, in the assembled state, has an arcuate shape, extending from the radially oriented holding region 30 to the free end at the coating 61.

[0034] It should be noted that in this embodiment, a coating 21a is also provided on the rigid lip 21 of the base part 2. Alternatively, only one coating may be provided on the rigid lip 21 or on the shaft sleeve 6.

[0035] How to continue Fig. 1 As can be seen, the support body 4 has a labyrinth seal 7 on a radial inner side. The labyrinth seal 7 acts as an additional throttling device to seal the product area 17 from the downstream area 18.

[0036] How to continue Fig. 1 As can be seen, a sliding sleeve 8, preferably made of PTFE, is also arranged in the labyrinth seal 7. The sliding sleeve 8 slides on the coating 61 of the shaft sleeve 6 and provides additional sealing.

[0037] Thus, starting from the product area 17, the first rigid lip 21, which contacts the coating 61, the second movable lip 3, the labyrinth seal 7 and the sliding sleeve 8 seal in the direction of the downstream area 18.

[0038] The lip seal 1 of the first exemplary embodiment is a preassembled unit that also includes a housing 9. The housing 9 has a first housing part 91 and a second housing part 92, which are connected to one another, for example, by means of a screw connection. A receiving area 22 is formed between the first and second housing parts 91, 92, in which the base part 2, the movable lip 3, and the support body 4 are arranged. This creates a second compensation chamber 90 radially outside the base part 2, which is designed to compensate for radial movements of the rotating component that can be exerted on the lip seal and in particular on the base part 2, such that the base part 2, the movable lip 3, and the support body 4 can follow the radial movements of the rotating component and the base part 2 does not strike the housing or another component.

[0039] Further preferably, a first sealing disc 11 and a second sealing disc 12 are provided. As shown in Fig. 1 As can be seen, the first sealing disc 11 is arranged between the housing 9 and the base part 2. The second sealing disc 12 is arranged between the support body 4 and the housing 9. The first and second sealing discs 11, 12 are preferably also made of PTFE and seal the radial gap between the housing 9 and the base part 2 or in the support body 4.

[0040] Although the contact between the rigid lip 21 of the base part 2 and the shaft sleeve 6 in the area of ​​the coating 61 does not completely seal the product area 17, since liquids and / or gases in particular can pass through the first contact area 60 into the movement space 5 to a small extent, a large portion of the liquids and / or gases, and in particular any solids contained in the product, can be retained. The contact of the movable lip 3 with the shaft sleeve 6 at the second contact area 62 further prevents the medium in the movement space 5 from spreading further towards the downstream area 18. Should something nevertheless pass through the second contact area 62, the labyrinth seal 7 with the integrated sliding sleeve 8, which slides and seals on the shaft sleeve 6, subsequently seals.This reliably prevents product from the product area 17 from passing through the lip seal 1 into the downstream area 18.

[0041] This makes it possible to arrange no or at most one additional seal, for example a mechanical seal, for sealing and as a safety seal on the rotating component in the downstream area 18. This allows the axial length of the sealing arrangement, for example of agitators, to be significantly reduced compared to the prior art, since only a single lip seal according to the invention and, if necessary, a single additional mechanical seal are required to ensure a secure seal from the product area 17 to the downstream area 18.

[0042] The lip seal 1 according to the invention can be provided as a pre-assembled unit and can thus be easily mounted on a rotating component.

[0043] Fig. 2 shows a lip seal 1 intended for sealing a rotating component according to a second embodiment of the invention. Identical or functionally identical parts are designated by the same reference numerals as in the first embodiment.

[0044] As from Fig. 2 As can be seen, in contrast to the first embodiment, the second embodiment provides a flushing option for the lip seal 1. In this case, a first channel 13 is provided in the base part 2, which leads through the main body 20 and the rigid lip 21 to the movement space 5. Furthermore, a second channel 14 is formed in the support body 4, which leads through the support body 4 to the labyrinth seal 7. In this case, a supply channel 15 is provided on a rear side 23 of the base part 2, which runs in the radial direction and supplies a flushing fluid to the first channel 13 and the second channel 14. The path of the flushing fluid is in Fig. 2 represented by the arrows 19. The flushing fluid is supplied through an opening 93 in the housing 9.

[0045] How to continue Fig. 2 As can be seen, a wide gap 94 is also provided in the housing 9, which is arranged in the region of the first sealing disc 11. This allows product to reach the radial inner side of the first sealing disc 11. This design has the advantage that, in particular, cleaning in the region of the gap 94 between the housing and the base part 2 can be made significantly easier, since the widened gap 94 allows very good accessibility to this otherwise very difficult-to-clean area.

[0046] How to continue Fig. 2As can be seen, grooves 32, which extend in the axial direction XX, are also formed on the movable lip 3 on an inner side of the movable lip region 31. The grooves 32 enable improved flushing in the region of the movable lip 3.

[0047] The lip seal 1 of the second embodiment can thus be cleaned more easily, since special flushing channels are provided for cleaning, allowing targeted cleaning of otherwise difficult-to-clean areas. Furthermore, it is also conceivable that, during operation of the lip seal 1, a barrier fluid is supplied through the channel arrangement as shown by arrows 19, thereby further improving the sealing effect of the lip seal. List of reference symbols

[0048] 1Lip seal 2Base part 3Second movable, flexible lip 4Support body 5Movement space 6Shaft sleeve 7Labyrinth seal 8Sliding sleeve 9Housing 10First compensation space 11First sealing disc 12Second sealing disc 13First channel 14Second channel 15Feed channel 16Clamp connection 17Product area 18Downstream area 19Flushing fluid 20Main body 21First rigid, inflexible lip 21aCoating on the rigid, inflexible lip 22Receiving area 23Rear side 30Retaining area 31Movable lip area 32Grooves 40Arched area 60First contact area 61Coating 62Second contact area 63Recess in the shaft sleeve 90Second compensation space 91First housing part 92Second housing part 93Opening 94Gap RRadial direction X-XAxial direction

Claims

1. Lip seal (1) for sealing on a rotating component, comprising: - a base part (2) having a main body (20) and a rigid lip (21), which is integrally arranged on the main body (20), - a movable lip (3) having a retaining area (30) and a movable lip area (31), and - a support body (4) which is firmly connected to the base part (2), - wherein the retaining area (30) of the movable lip (3) is rigidly clamped between the base part (2) and the support body (4) - wherein a movement space (5) for movement of the movable lip (3) is formed on the movable lip (3), characterized in that the lip seal (1) further comprises a housing (9), in which the base part (2) and the support body (4) are at least partially received, wherein a compensation space (90) for a radial movement of the base part (2) is formed radially outside the base part (2) between the base part (2) and the housing (9).

2. Lip seal according to claim 1, wherein the movement space (5) is formed between the movable lip (3) and the rigid lip (21).

3. Lip seal according to claim 2, wherein the movement space (5) facilitates a movement of the movable lip (3) in the radial direction and the axial direction (X-X).

4. Lip seal according to any one of the preceding claims, - wherein the movable lip (3) is produced from a flexible material, and / or - wherein the base part (2) and the support body (4) are produced from a hard material.

5. Lip seal according to any one of the preceding claims, wherein the rigid lip (21) is arranged on the main body (20) of the base part (2) such that a receiving area (22) for receiving the movable lip (3) and the support body (4) is formed adjacent to the rigid lip (21).

6. Lip seal according to any one of the preceding claims, wherein the support body (4) comprises an arcuate area (40) on which the movable lip (3) at least partially rests.

7. Lip seal according to any one of the preceding claims, further comprising a shaft sleeve (6), wherein the rigid lip (21) of the base part contacts the shaft sleeve (6) at a contact area (60) in a non-fully sealing manner.

8. Lip seal according to claim 7, wherein the shaft sleeve (6) comprises a coating (61) on the contact area (60) and / or wherein the rigid lip (21) comprises a coating (21a) on the contact area.

9. Lip seal according to any one of the preceding claims, wherein the support body (4) comprises a labyrinth seal (7) on a radial inner side and / or wherein the support body (4) comprises a sliding sleeve (8) on a radial inner side.

10. Lip seal according to any one of the preceding claims, wherein the support body (4) and the base part (2) are firmly connected to each other by means of a clamp connection (16).

11. Lip seal according to any one of the preceding claims, wherein a first disc-shaped sealing element (11) is arranged between the housing (9) and the base part (2) and a second disc-shaped sealing element (12) is arranged between the housing (9) and the support body (4).

12. Lip seal according to claim 11, wherein the first disc-shaped sealing element (11) is at least partially exposed to the medium (17) to be sealed at a radially inwardly directed area.

13. Lip seal according to any one of the preceding claims, wherein the movable lip (3) comprises a plurality of grooves (32) in the movable lip area (31) on a radially inwardly directed side.

14. Lip seal according to any one of the preceding claims, - wherein a first channel (13) is formed in the base part (2), which extends through the main body (20) and the rigid lip (21) and opens out in the movement space (5) between the movable lip (3) and the rigid lip (21) and / or - wherein a second channel (14) is formed in the support body (4), which extends from an outer side of the support body (4) to a radially inner side of the support body (4).