Lip seal having movable and rigid lips

Abstract

The invention relates to a lip seal (1) for sealing at a rotary member, comprising a base (2) with a main body (20) and a rigid lip (21) which is arranged integrally at the main body (20), a movable lip (3) with a holding region (30) and a movable lip region (31), and a support body (4) which is connected firmly to the base (2), wherein the movable lip (3) is clamped firmly between the base (2) and the support body (4) at the holding region (30), and wherein a movement space (5) for the movement of the movable lip (3) is formed at the movable lip (3).

Description

TECHNICAL FIELD

[0001] The present application relates to a lip seal having two lips, namely a first rigid lip and a second movable flexible lip, and in particular a blender lip seal or a lip seal for a screw conveyor or the like. BACKGROUND

[0002] Different designs of lip seals are known from the prior art. Fields of application of the lip seals are for example for sealing blender shafts, wherein the blender shafts are usually arranged vertically. Here, the lip seals are usually arranged at the shaft in a manner connected with a plurality of serially connected circular seals. The lip seals are usually made of a flexible material and have a gradually tapering lip end region, which abuts at the shaft or the like to be sealed. For example, a shaft guide having a throttle and wiping device connected before the actual sealing device is known from DE 20 2009 013 547 U1. The lip of the wiping device is here arranged in a contactless manner at the rotating component and serves for rejecting particles and protecting the sealing device arranged behind. However, this device requires a relatively large structural length in the axial direction of the shaft to be sealed. SUMMARY

[0003] It is an object of the present application to provide a lip seal which, with a simple structure and easily and cost-effectively producible, can itself also provide a sealing, so that subsequently no or only a very small amount of additional sealing for sealing at the shaft is required.

[0004] This object is achieved by a lip seal having the features of claim 1. The dependent claims give preferred refinements of the application.

[0005] The lip seal according to the application having the features of claim 1 has the advantage that the lip seal itself can alone provide a very good sealing action at a rotating component, for example at a shaft or a shaft sleeve. Here, the lip seal has a very simple and cost-effective structure. In particular, the lip seal is suitable for sealing a blender shaft of a blender in the chemical industry or the food industry or the like. Here, the lip seal for sealing at a rotating component comprises a base, a second movable flexible lip and a support. The base 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 is firmly connected with the base. The movable lip is here firmly clamped between the base and the support at its holding region. At the movable lip there is also formed a movement space for the movement of the movable lip. Thereby, in particular temperature-dependent length changes of the component can be compensated. Furthermore, by the movement space a defined mobility of the movable lip at the rotating component to be sealed is ensured, which can compensate for small deviations of the rotating component.

[0006] In order to be able to compensate for a radial displacement of the rotary member, the movement space is preferably formed between a rigid lip of the base and the movable lip.

[0007] The movement space at the movable lip can here preferably also enable a movement of the movable lip in the radial direction and in the axial direction. Radial and / or axial displacements of the rotary member can thereby be compensated for.

[0008] Further preferably, the movable lip is made of a flexible material, in particular a PTFE- containing material having a high flexibility. The base and the support are preferably made of a non- flexible, hard material, in particular a metal material.

[0009] The base further preferably comprises a receiving region for the movable lip and the support, which receiving region is arranged at the main body of the base. A very compact and space-saving design can thereby be achieved.

[0010] Further preferably, the support has an arc-shaped region, against which the movable lip abuts. The movable lip can thereby abut to the arc-shaped region corresponding to the design of the arc-shaped region of the support and thereby improve the sealing function.

[0011] Further preferably, the lip seal also comprises a sleeve, wherein the fixed lip contacts the sleeve in an incompletely sealing manner at the contact region. The rigid lip and the sleeve thereby contact one another, however such that a complete sealing effect is not achieved, but rather, in particular, solids in the medium to be sealed can be kept away from the lip seal and only a minimal leakage of gas or liquid reaches the movable lip via the rigid lip of the base.

[0012] The sleeve particularly preferably has a coating at the contact region. The frictional resistance of the rigid lip at the sleeve is thereby reduced. It is particularly preferred here that a recess is formed in the sleeve, which recess is filled in this case with the material of the coating. Alternatively or additionally, the rigid lip of the base has a coating. The friction value between the rigid lip and the rotary member, in particular the sleeve, can thereby be reduced.

[0013] In order to improve the sealing effect of the lip seal, the support preferably has a labyrinth seal on the radially inner side. The lip seal according to the application thereby comprises at least three sealing regions in series, namely the first rigid lip, the second movable lip and the labyrinth seal.

[0014] In order to achieve a better sealing, the support comprises a slide bush on its radially inner side. The slide bush contacts the rotary member and is preferably made of PTFE. It is particularly preferred that a coating is provided at the rotary member in the region of the slide bush. The slide bush provides a fourth sealing region.

[0015] According to a further preferred design of the application, the lip seal further comprises a housing having a receiving space in which the base and the support body as well as the movable lip are at least partially received. Here, a compensation space is formed radially outside the base between the base and the housing for the radial movement of the base into the compensation space. The housing is preferably constructed in two parts, whereby the installation of the lip seal is significantly simplified.

[0016] Preferably, the support body and the base are firmly connected to one another. The connection between the support body and the base is preferably a clamping connection. Alternatively, a threaded connection or a connection by means of a press pin is provided between the support body and the base.

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

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

[0019] According to a further preferred design of the application, the lip seal has a flushing possibility. Here, a first channel is preferably formed in the base, which runs through the main body and the rigid lip. The first channel here 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 the outside of the support body to the radially inner side of the support body.

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

[0021] In order to be able to accommodate the particularly temperature-dependent length changes of the movable lip in the radial direction, a radial compensation space is preferably provided at the end of the holding region of the movable lip. It can thus be ensured that the radial extension of the movable lip is possible even in the event of temperature changes, so that no deterioration of the sealing by the movable lip occurs when the ambient temperature changes or the temperature of the medium to be sealed changes.

[0022] Furthermore, the application relates to a sealing arrangement comprising a lip seal according to the application and an additional seal, in particular a slide ring seal, in series with the lip seal. Since the lip seal itself has a sealing effect, it is possible to achieve a sufficient sealing at the rotating member, in particular the stirrer shaft, by means of only one additional seal in series. BRIEF DESCRIPTION OF DRAWINGS

[0023] In the following, a preferred embodiment of the application is described in detail with reference to the drawings. The drawings show:

[0024] Figure 1 a schematic partial cross-sectional view of a lip seal according to a first embodiment of the application, and

[0025] Figure 2 a schematic partial cross-sectional view of a lip seal according to a second embodiment of the application. DETAILED DESCRIPTION

[0026] In the following, reference is made to Figure 1 The lip seal 1 according to a first preferred embodiment of the application is described in detail.

[0027] Here, the lip seal 1 seals the product area 17 against a downstream area 18, for example an atmospheric area. As can be seen from Figure 1 It can be seen that the lip seal 1 comprises a hard base 2 which has a main body 20 and a rigid, inflexible lip 21 which is arranged integrally thereat. The lip 21 has a tapered end.

[0028] The tapered end is in contact with the rotating member, in this embodiment with the shaft sleeve 6. From Figure 1 It can be seen that a coating 61 is provided on the shaft sleeve 6 which fills a groove 63 in the outer circumference of the shaft.

[0029] The rigid lip 21 of the base 2 abuts at the first contact area 60 in the region of the coating 61 at the shaft sleeve 6 in an incompletely sealing manner.

[0030] The lip seal 1 further comprises a second movable lip 3 which is for example made of PTFE. The movable lip 3 comprises a holding region 30 and a movable lip region 31. The holding region 30 is arranged in the radial direction R and the movable lip region 31 contacts the surface of the rotating member at a second contact area 62.

[0031] The lip seal 1 further comprises a hard support body 4 which is firmly connected with the base 2. In this embodiment, a clamping connection 16 is formed between the support body 4 and the base 2.

[0032] The movable lip 3 is firmly clamped between the base 2 and the support body 4 at the holding region 30. A first radial compensation space 10 is formed radially beyond the holding region 30.

[0033] Furthermore, a movement space 5 is formed at the movable lip 3. From Figure 1As can be seen from Figure 1 As can be seen from

[0034] As can be seen from Figure 1 It can further be seen that the movable lip 3 and the support body 4 are arranged in the receiving area 22 of the base 2. Here, the back of the support body 4 is closed flush with the main body 20 of the base 2.

[0035] The support body 4 has an arc-shaped area 40, against which the movable lip 3 rests. Thereby, the movable lip 3 has an arc-shaped shape in the mounted state from the radially oriented holding area 30 to the free end at the coating 61.

[0036] It should be noted that in this embodiment, a coating 21a is also provided at the rigid lip 21 of the base 2. Alternatively, only one coating can also be provided at the rigid lip 21 or at the shaft sleeve 6.

[0037] As can be further seen from Figure 1 It can further be seen that the support body 4 has a labyrinth seal 7 radially inside. The labyrinth seal 7 serves here as an additional throttling means to seal the product area 17 against the downstream arranged area 18.

[0038] As can be further seen from Figure 1 It can further be seen that 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 an additional seal.

[0039] Thus, starting from the product area 17, the first rigid lip 21, the second movable lip 3, the labyrinth seal 7 and the sliding sleeve 8, which first contact the coating 61, seal against the downstream area 18.

[0040] The lip seal 1 of the first embodiment is a pre-installed assembly, which also includes a housing 9. The housing 9 has a first housing component 91 and a second housing component 92, which are connected to each other, for example, by means of a threaded connection. Here, a receiving area 22 is formed between the first housing component 91 and the second housing component 92, in which the base 2, the movable lip 3, and the support 4 are arranged. Here, a second compensation space 90 is formed radially outside the base 2, which is provided to compensate for the radial movement of the rotating member (which can be applied to the lip seal and especially the base 2), so that the base 2, the movable lip 3, and the support 4 can follow the radial movement of the rotating member and the base 2 does not collide with the housing or other components.

[0041] More preferably, a first sealing gasket 11 and a second sealing gasket 12 are provided. For example, from... Figure 1 As can be seen, the first sealing gasket 11 is arranged between the housing 9 and the base 2. The second sealing gasket 12 is arranged between the support 4 and the housing 9. The first sealing gasket 11 and the second sealing gasket 12 are preferably both made of PTFE and seal the radial gap between the housing 9 and the base 2 or in the support 4.

[0042] Although the contact between the rigid lip 21 of the base 2 and the bushing 6 in the area of ​​the coating 61 does not completely seal the product area 17 because liquids and / or gases, in particular, can pass through the first contact area 60 to reach the movement space 5 in a small area, most of the liquids and / or gases, as well as solids that may be contained in the product, can be blocked. The contact between the movable lip 3 and the bushing 6 at the second contact area 62 further prevents the medium in the movement space 5 from continuing to diffuse towards the downstream area 18. However, if anything passes through the second contact area 62, the labyrinth seal 7 immediately seals with the integrated sliding sleeve 8, which slides on the bushing 6 and seals. Therefore, it is reliably prevented that product from the product area 17 can reach the downstream area 18 via the lip seal 1.

[0043] Therefore, it is feasible to eliminate the need for, or at most require, one additional seal, such as a slip ring seal, in the downstream region 18 for sealing and as a safety seal at the rotating component. This significantly reduces the axial structural length of the sealing device (e.g., an agitator) compared to the prior art, because only a single lip seal according to the invention and, if necessary, a single additional slip ring seal are required to ensure a reliable seal from the product region 17 to the downstream region 18.

[0044] The lip seal 1 according to the invention can be configured as a pre-installable unit and thus simply installed at the rotating member.

[0045] Figure 2 A lip seal 1 for sealing arrangement at a rotary member according to a second embodiment of the application is shown. Identical or functionally identical parts are denoted with the same reference numerals as in the first embodiment.

[0046] As can be seen from Figure 2 the flushing possibility of the lip seal 1 is given in the second embodiment, unlike in the first embodiment. Here, a first channel 13 is provided in the base 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. Here, a supply channel 15 is provided at the back side 23 of the base 2, which extends in the radial direction and supplies flushing fluid to the first channel 13 and the second channel 14. The path of the flushing fluid is shown in Figure 2 by the arrows 19. The flushing fluid is supplied here through an opening 93 in the housing 9.

[0047] As can be further seen from Figure 2 a wide gap 94 is also provided in the housing 9, which is arranged in the region of the first sealing washer 11. By this, the product can reach the radially inner side of the first sealing washer 11. The advantage of this design is that, in particular, the cleaning in the region of the gap 94 between the housing and the base 2 can be significantly simplified, since by the widened gap 94 a very good accessibility to otherwise very difficult to clean regions is achieved. As can be further seen from Figure 2 a slot 32 is also formed at the movable lip 3 at the inner side of the movable lip region 31, which extends in the axial direction X-X. The slot 32 here enables an improved flushing in the region of the movable lip 3.

[0048] Thus, the lip seal 1 of the second embodiment can be cleaned on the one hand more simply, since a flushing channel for cleaning is provided and can be cleaned purposefully at otherwise difficult to clean points. It can also be considered that in the operation of the lip seal 1 a barrier fluid is supplied through the channel means corresponding to the arrows 19, whereby the sealing action of the lip seal is further improved.

[0049] List of reference numerals

[0050] 1 lip seal

[0051] 2 base

[0052] 3 second movable flexible lip

[0053] 4 support body

[0054] 5 movement space

[0055] 6 shaft sleeve

[0056] 7 labyrinth seal

[0057] 8 slide sleeve

[0058] 9 housing

[0059] 10 first compensation space

[0060] 11 first sealing washer

[0061] 12 second sealing washer

[0062] 13 first channel

[0063] 14 second channel

[0064] 15 supply channel

[0065] 16 clamping connection

[0066] 17 product area

[0067] 18 downstream area

[0068] 19 flushing fluid

[0069] 20 main body

[0070] 21 first rigid, non-flexible lip

[0071] 21a coating at the rigid, non-flexible lip

[0072] 22 receiving area

[0073] 23 back side

[0074] 30 holding area

[0075] 31 movable lip area

[0076] 32 slot

[0077] 40 arc-shaped area

[0078] 60 first contact area

[0079] 61 coating

[0080] 62 second contact area

[0081] 63 recess in the shaft sleeve

[0082] 90 second compensation space

[0083] 91 first housing part

[0084] 92 second housing part

[0085] 93 opening

[0086] 94 gap

[0087] R radial direction

[0088] X-X axial direction.

Claims

1. A lip seal (1) for sealing at a rotating member, comprising: - A base (2) having a body (20) and a rigid lip (21) integrally disposed on the body (20). -A movable lip (3) having a retaining region (30) and a movable lip region (31), and - A support (4) that is firmly connected to the base (2). - wherein the movable lip (3) is securely held between the base (2) and the support (4) at the retaining area (30), and -A movement space (5) for the movement of the movable lip (3) is formed at the movable lip (3). The lip seal (1) is further provided with a housing (9) in which the base (2) and the support (4) are received at least partially, wherein a compensating space (90) for radial movement of the base (2) is formed between the base (2) and the housing (9) radially outside the base (2).

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

3. The lip seal according to claim 2, wherein the movement space (5) enables the movable lip (3) to move in the radial and axial directions (XX).

4. The lip seal according to any one of claims 1 to 3, - wherein the movable lip (3) is made of a flexible material, and / or -The base (2) and the support (4) are made of hard material.

5. The lip seal according to any one of claims 1 to 3, wherein the rigid lip (21) is disposed at the body (20) of the base (2) such that a receiving area (22) for receiving the movable lip (3) and the support (4) is formed adjacent to the rigid lip (21).

6. The lip seal according to any one of claims 1 to 3, wherein the support (4) has an arcuate region (40), and the movable lip (3) at least partially abuts against the arcuate region.

7. The lip seal according to any one of claims 1 to 3, further comprising a bushing (6), wherein the rigid lip (21) of the base contacts the bushing (6) at the contact area (60) in a partially sealing manner.

8. The lip seal according to claim 7, wherein the bushing (6) has a coating (61) at the contact area (60), and / or wherein the rigid lip (21) has a coating at the contact area.

9. The lip seal according to any one of claims 1 to 3, wherein the support (4) has a labyrinth seal (7) on the radially inner side, and / or wherein the support (4) has a sliding sleeve (8) on the radially inner side.

10. The lip seal according to any one of claims 1 to 3, wherein the support (4) and the base (2) are securely connected to each other by means of a clamping connection (16).

11. The lip seal according to claim 1, wherein a first washer-shaped sealing element (11) is arranged between the housing (9) and the base (2), and a second washer-shaped sealing element (12) is arranged between the housing (9) and the support (4).

12. The lip seal according to claim 11, wherein the first washer-shaped sealing element (11) is at least partially exposed to the medium to be sealed (17) in the radially inwardly pointing region.

13. The lip seal according to any one of claims 1 to 3, wherein the movable lip (3) has a plurality of grooves (32) on the radially inward side of the movable lip region (31).

14. The lip seal according to any one of claims 1 to 3, -A first channel (13) is formed in the base (2), the first channel extending through the body (20) and the rigid lip (21) and opening into the movement space (5) between the movable lip (3) and the rigid lip (21), and / or -A second channel (14) is formed in the support (4), the second channel extending from the outside of the support (4) to the radial inside of the support (4).

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