Sealing device for a shaft passage

Abstract

Sealing device (1) for a shaft passage, comprising a housing (10) which has an opening (11) for the passage of a shaft (200) and an annular groove (12), a rigid ring (30) which is arranged with axial and radial play in the annular groove (12) of the housing (10), has a through-hole (31) for the passage of the shaft (200) and has an annular groove (33) on an inner circumferential surface (32) of its through-hole (31), and an elastic ring (40) which is arranged in the annular groove (33) of the rigid ring (30), characterized by a sliding band (50) for bearing against the shaft (200), which is arranged circumferentially on the inner circumferential surface (32) of the through-opening (31) of the rigid ring (30) and covers the annular groove (33) of the rigid ring (30) with the elastic ring (40) arranged therein, wherein the elastic ring (40) is pressed against the sliding band (50), wherein the sliding band (50) is raised radially inwards above the inner circumferential surface (32) of the through-opening (31) of the rigid ring (30).

Description

[0001] The invention relates to a sealing device for a shaft passage with the features of the preamble of claim 1.

[0002] Such a sealing device is used as an emergency system, for example, at a shaft penetration in a ship's bulkhead, to prevent water from flowing along a propeller shaft from one compartment to another. Under normal operating conditions, the sealing device is ineffective and should not impair the shaft's movement. Furthermore, it must be ensured that the sealing device is sufficiently wear-resistant and operates smoothly so that it functions effectively when stressed.

[0003] Ingressing water forces the rigid ring against a side flank of the housing's annular groove, creating the desired seal against the housing at that point, while the elastic sealing ring seals the interface between the rigid ring and the shaft. For the rigid ring to come into contact with the side flank of the groove, it must be displaced slightly axially on the shaft.

[0004] If the elastic ring is compressed too much, the rigid ring cannot move axially enough on the shaft to close the seal between the rigid ring and the housing. If the compression of the elastic ring is too low, the shaft can rotate relative to it if the rigid ring is slowed down, for example, by running against a side flank of the housing's ring groove. Such running against can be caused by air pressure differences in the chambers. This slowing of the elastic ring can lead to increased wear, so that in the event of water ingress, water can penetrate between the shaft and the rigid ring. Vibrations occurring on the shaft can accelerate premature wear of the elastic ring.

[0005] Generic sealing devices with the features of the preamble of claim 1 are also known from US 4,177,997 A, CN 103274029 A and CN 109606535 A. The problems associated with such a sealing device are explained in WO 2011 / 129870 A1.

[0006] US 4,177,997 A discloses a floating sealing ring arrangement with a sliding ring having an annular groove opening in which an annular sealing element is supported. The annular sealing element has a wear surface that slidably engages with an outer surface on the shaft. The outer surface is provided on a sleeve attached to the shaft, so that the sliding ring can move relative to the sleeve.

[0007] Another sealing device for a shaft passage is described in EP 0092072 A1.

[0008] Furthermore, Espey Burgmann GmbH offers a bulkhead seal designated WDK-BHS, which features two multi-part PTFE sealing rings. Each ring is held in a corresponding annular groove in a housing and pressed against the rotating shaft by a circumferential coil spring. However, strong radial and axial vibrations can lead to premature wear of the delicate sealing rings.

[0009] The present invention aims to remedy this problem. In particular, the invention seeks to improve the robustness of a generic sealing device when radial and axial vibrations occur on the shaft.

[0010] This problem is solved by a sealing device having the features of claim 1.

[0011] The solution according to the invention enables a robust design through the use of a solid rigid ring while simultaneously exhibiting very low wear. In particular, the sliding band prevents direct wear of the elastic ring. This, in turn, ensures that the rigid ring can be axially displaced on the shaft when necessary, so that the sealing device becomes effective.

[0012] Nevertheless, a high level of sealing between the rigid ring and the shaft is still ensured in the radial direction.

[0013] The solution according to the invention thus avoids the problems inherent in the prior art explained above in a simple and elegant way.

[0014] Specific embodiments of the invention are the subject of further patent claims.

[0015] Furthermore, the rigid ring can have a receiving groove for the sliding band on the inner circumferential surface of its through-hole, wherein the groove depth is less than the wall thickness of the sliding band. This prevents axial slippage of the sliding band. This is particularly important if axial vibrations can occur on the shaft.

[0016] It has been shown that a wall thickness of 1 to 3 mm is advantageous for the sliding belt.

[0017] In a special design, the sliding belt can have or be formed from a film, the film material being selected from the following group: polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PETP), polyoxymethylene (POM), polyetheretherketone (PEEK), and ultra-high molecular weight polyethylene (UHMWPE). This ensures particularly low friction with high wear resistance.

[0018] In another particular embodiment of the invention, the elastic ring can be made of neoprene. Such chloroprene rubbers are characterized by high weather resistance as well as good resistance to oils and greases. Furthermore, the material is self-extinguishing.

[0019] However, depending on the application, other materials can be used for the elastic ring instead of neoprene.

[0020] In another particular embodiment of the invention, the rigid ring consists of a fiber-reinforced plastic composite material and / or metal. Since the rigid ring is connected to the shaft and sometimes rotates with the shaft, a particularly low component weight is desirable, so fiber-reinforced plastic composite materials are preferably used.

[0021] According to another special embodiment, the cross-section of the rigid ring is configured such that it tapers radially inwards towards the through-opening. This creates a narrow, annular contact area for bearing against a side flank of the annular groove of the housing, thereby achieving a particularly high sealing effect.

[0022] According to another special embodiment, part of the housing can be formed by a section of the wall through which the shaft is to pass. In this case, the housing is formed by a wall, in particular a bulkhead, and a cover such that one side flank of the annular groove of the housing is provided by the wall and the opposite side flank of the annular groove of the housing is provided by the cover. The width of the annular groove is dimensioned such that the rigid ring can be axially floating within it.

[0023] Alternatively, the housing can also be provided as a separate component, which is then attached to the wall. In this case, the housing comprises a housing ring and a cover, with one side flank of the housing's annular groove being provided by the housing ring and the opposite side flank of the housing's annular groove being provided by the cover. The housing ring has fastening devices for securing the housing to a wall, particularly a partition wall. Here, too, the rigid ring is axially suspended within the housing's annular groove.

[0024] The invention of an embodiment illustrated in the drawing is explained in more detail below. The drawing shows: Fig. 1 a schematic representation of an installation situation of a sealing device according to an embodiment of the invention on a wall with shaft passage, Fig. 2 a longitudinal sectional view of the sealing device Fig. 1, and in Fig. 3 a cross-sectional view of the sealing device Fig. 1.

[0025] The exemplary embodiment shows a sealing device 1 for a shaft passage through a wall 100. Fig. Figure 1 shows wall 100 as a bulkhead of a ship, separating two ship compartments A and B. A shaft 200 is also visible, extending through wall 100. This shaft 200 could, for example, be a propeller shaft of the ship.

[0026] The sealing device 1 is arranged between the wall 100 and the shaft 200. Its purpose is to prevent, or at least slow down, the passage of liquid, for example water, into one of the chambers A or B from the other chamber B or A, so that passengers and crew can be brought to safety or the ship can reach a port. Liquid present at the sealing device 1 causes it to seal. In normal operation, i.e., without liquid present, a sealing effect is not required.

[0027] The sealing device 1 initially comprises a housing 10, which is attached to the wall 100. Alternatively, sections of the housing 10 can also be integrated into the wall 100.

[0028] How in particular Fig. As shown in Figure 2, the housing 10 has an opening 11 for the passage of the shaft 200 and also an annular groove 12. The annular groove 12 extends around the shaft 200 and is open towards the shaft 200.

[0029] In the illustrated embodiment, the housing 10 comprises a housing ring 13 and a cover 14. A first side flank 15 of the annular groove 12 of the housing 10 is provided by the housing ring 13, and the opposite side flank 16 of the annular groove 12 of the housing 10 is provided by the cover 14. A groove base 17 of the annular groove 12 of the housing 10 can be formed either on the housing ring 13 or on the cover 14. It is also possible to form the groove base 17 by wall sections on both the housing ring 13 and the cover 14.

[0030] The cover 14 is attached to the housing ring 13 and sealed against it. The housing ring 13 itself has fastening devices 18, for example, fastening holes, for securing the housing 10 to the wall 100. In the illustrated embodiment, the housing ring 13 is screwed to the wall 100 by means of threaded bolts 19, including a seal 20. However, it is also possible to attach the cover 14 directly to the wall 100 and, if necessary, to additionally secure the housing ring 13 to the wall 100.

[0031] Alternatively, the housing ring 13 can also be integrated in one piece into the wall 100, such that the first side flank 15 of the annular groove 12 of the housing 10 is provided by the wall 100 and the opposite side flank 16 of the annular groove 12 of the housing 10 is provided by the cover 14.

[0032] Furthermore, the sealing device 10 has a rigid ring 30 which is arranged in the annular groove 12 of the housing 10 with axial and radial play. The axial play can be on the order of a few tenths of a millimeter and is not shown to scale in the accompanying figures. Preferably, the axial play to the side flanks 15 and 16 of the annular groove 12 is 0.2 to 2.0 mm. A comparable play can be selected in the radial direction. However, since this radial play is of minor importance, the outer circumference of the rigid ring 30 can also have a greater distance to the groove base 17 of the annular groove 12, as is qualitatively shown in Fig. 2 can be seen.

[0033] The rigid ring 30 has a through-opening 31 for the passage of the shaft 200. Furthermore, it has an annular groove 33 on an inner circumferential surface 32 of its through-opening 31.

[0034] The rigid ring 30 is preferably made of a fiber-reinforced plastic composite material to keep its component weight low. However, it can also be made of metal or a combination of metal and fiber-reinforced plastic composite material.

[0035] Furthermore, the rigid ring 30 can have a cross-section that tapers radially inwards towards the through-opening 31. This ensures, if necessary, a good sealing effect against the relevant side flank 15, 16 of the annular groove 12 of the housing 10 when fluid is axially present against the rigid ring 30. The cross-section of the rigid ring 30 can taper conically inwards in the radial direction, as shown in Fig. 2 can be seen. However, other cross-sectional profiles that taper radially inwards are also possible.

[0036] An elastic ring 40 is arranged in the annular groove 33 of the rigid ring 30. The terms "rigid" and "elastic" are to be understood here as qualitatively distinct from one another, namely that the elastic ring 40 has a significantly higher elasticity than the rigid ring 30. The elastic ring 40 is softer than the rigid ring 30.

[0037] The two rings 30, 40 form, in a sense, a double sealing ring with a soft shaft seal over the ring 40 and a harder retaining sealing ring in the form of the ring 30, which receives the soft shaft seal and seals against the housing 10.

[0038] The elastic ring 40, which is preferably designed as an O-ring, can have a round cross-section. However, other cross-sectional shapes are also possible.

[0039] Preferably, the elastic ring 40 is made of neoprene or a comparable rubber. However, other elastically compressible materials can also be used for the elastic ring 40.

[0040] Furthermore, the sealing device 10 has a sliding band 50 for contact against the shaft 200.

[0041] This sliding belt 50 consists preferably of a friction-reducing material on its surface facing the shaft 200.

[0042] It is arranged around the inner circumferential surface 32 of the through opening 31 of the rigid ring 30 and simultaneously covers the annular groove 33 of the rigid ring 30 with the elastic ring 40 arranged in said annular groove 33 on the side towards the shaft 200.

[0043] The annular groove 33 and the elastic ring 40 are preferably aligned such that the elastic ring 40 is pressed against the sliding band 50. In other words, the elastic ring 40, which is supported radially outwards in the annular groove 33 of the rigid ring 30, presses against the radial outer wall of the sliding band 50.

[0044] In its installed state, the sealing device 10 is pressed by the elastic ring 40 against the outer circumference of the shaft 200, thus elastically sealing the gap between the rigid ring 30 and the shaft 200 against the passage of liquid. This allows vibrations of the shaft 200 in the radial direction to be compensated without impairing the sealing effect.

[0045] The sliding band 50 seals the rigid ring 30 in the area of ​​the annular groove 33 and the elastic ring 40 against the shaft 200. The elastic ring 40 acts as a seal between the sliding band 50 and the annular groove 33.

[0046] In addition, the sliding band 50 ensures that the rigid ring 30 can be easily moved axially on the shaft 200 when liquid is present, so that the rigid ring 30 can, if necessary, come into sealing contact with one of the side flanks 15, 16 of the ring groove 12 of the housing 10 through the presence of liquid.

[0047] Furthermore, the sliding band 50 prevents premature wear of the elastic ring 40 by avoiding friction between the elastic ring 40 and the shaft 200. This significantly improves the wear resistance of the sealing device 10 and thus massively reduces the risk that it will become ineffective due to wear when needed.

[0048] The sealing device 10 therefore combines high robustness with high wear resistance and service life, so that maintenance intervals can be significantly extended.

[0049] The sliding belt 50 can, for example, have a film or consist of one. The material of the film is preferably selected from the group comprising: polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PETP), polyoxymethylene (POM) or polyetheretherketone (PEEK) and ultra-high molecular weight polyethylene (UHMWPE).

[0050] The sliding band 50 can be raised radially inwards above the inner circumferential surface 32 of the through-opening 31 of the rigid ring 30.

[0051] Furthermore, the rigid ring 30 can have a receiving groove 34 for the sliding band 50 on the inner circumferential surface 32 of its through-opening 31. The groove depth of the receiving groove 34 is less than the wall thickness of the sliding band 50.

[0052] Preferably, the wall thickness of the sliding band 50 is 1 to 3 mm. The width of the sliding band 50 is a multiple of the wall thickness. It is preferably in the range of 10 to 30 mm.

[0053] To facilitate assembly with the shaft 200 already installed, the housing 10, the seal 20, the rigid ring 30 and, if necessary, the elastic ring 40 can be divided circumferentially into two or more segments, which are connected to each other during assembly. Fig. Figure 3 shows an example of a division of the rigid ring 30 into two segments, which are connected to each other by means of threaded bolts 60.

[0054] In normal operation of the sealing device 10, the rigid ring 30 is slightly radially preloaded against the shaft 200 via the elastic ring 40, so that the rigid ring 30 rotates with the shaft 200. A sealing effect exists between the rigid ring 30 and the shaft 200. Due to its axial and radial play in the annular groove 12, the two chambers A and B are in communication with each other via the corresponding gaps between the rigid ring 30 and the annular groove 12, so that, in principle, liquid and gas transfer is possible. If, during normal operation, the rigid ring 30 contacts one of the side flanks 15, 16 of the annular space 12 of the housing 10, for example as a result of axial vibrations of the shaft 200, the rigid ring 30 is braked by the housing 10. The resulting relative movement to the shaft 200 occurs primarily between the sliding band 50 and the shaft 200, thus preventing wear on the elastic ring 40.

[0055] If liquid enters one of chambers A or B and accumulates against the rigid ring 30, the liquid, because it cannot escape quickly due to the throttling effect of the gaps, is forced by the liquid against one of the side walls 15, 16 of the annular groove 12 of the housing 10. This seals the rigid ring 30 against the housing 10, thus preventing substantial liquid passage. The shaft 200 can continue to rotate to maintain operation, for example, the maneuverability of a ship.

[0056] The sealing device 10 was described above in connection with a bulkhead on a ship and its propeller shaft. However, it can also be used in other application environments where high robustness and wear resistance are required for a floating shaft seal. In this respect, the bulkhead described above should not be understood as limited to a ship bulkhead, nor should the shaft described above be understood as limited to a propeller shaft.

[0057] The invention has been explained in more detail above with reference to an exemplary embodiment and further modifications, which serve to demonstrate the feasibility of the invention. However, it is not limited to the exemplary embodiment and the further modifications, but encompasses all embodiments defined by the claims. In particular, the features explained above can also be combined with one another, even if this is not expressly mentioned, as long as this is technically possible. Such combinations and sub-combinations are hereby included in the present disclosure and are not described again separately for the sake of conciseness.

Claims

[1] Sealing device (1) for a shaft passage, comprising a housing (10) which has an opening (11) for the passage of a shaft (200) and an annular groove (12), a rigid ring (30) which is arranged with axial and radial play in the annular groove (12) of the housing (10), has a through-hole (31) for the passage of the shaft (200) and has an annular groove (33) on an inner circumferential surface (32) of its through-hole (31), and an elastic ring (40) which is arranged in the annular groove (33) of the rigid ring (30), characterized by a sliding band (50) for bearing against the shaft (200), which is arranged circumferentially on the inner circumferential surface (32) of the through-opening (31) of the rigid ring (30) and covers the annular groove (33) of the rigid ring (30) with the elastic ring (40) arranged therein, wherein the elastic ring (40) is pressed against the sliding band (50), wherein the sliding band (50) is raised radially inwards above the inner circumferential surface (32) of the through-opening (31) of the rigid ring (30). [2] Sealing device (1) according to claim 1, characterized by , that the rigid ring (30) has a receiving groove (34) for the sliding band (50) on the inner circumferential surface (32) of its through-hole (31), wherein a groove depth of the receiving groove (34) is less than the wall thickness of the sliding band (50). [3] Sealing device (1) according to claim 1 or 2, characterized by , that the sliding belt (50) has a wall thickness of 1 to 3 mm. [4] Sealing device (1) according to one of claims 1 to 3, characterized by , that the sliding belt (50) has a film, wherein the material of the film is selected from a group comprising: polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PETP), polyoxymethylene (POM) or polyetheretherketone (PEEK) and ultra-high molecular weight polyethylene (PE-UHMW). [5] Sealing device (1) according to any one of claims 1 to 4, characterized by , that the elastic ring (40) is made of neoprene. [6] Sealing device (1) according to any one of claims 1 to 5, characterized by , that the rigid ring (30) consists of a fiber-reinforced plastic composite material and / or metal. [7] Sealing device (1) according to any one of claims 1 to 6, characterized by , that the cross-section of the rigid ring (30) tapers radially inwards towards the through-opening (31). [8] Sealing device (1) according to any one of claims 1 to 7, characterized by , that the housing (10) is formed by a wall (100), in particular a bulkhead, and a cover (14) such that a side flank (15) of the annular groove (12) of the housing (10) is provided by the wall (100) and the opposite side flank (16) of the annular groove (12) of the housing (10) is provided by the cover (14). [9] Sealing device (1) according to any one of claims 1 to 7, characterized by , that the housing (10) has a housing ring (13) and a cover (14), wherein a side flank (15) of the annular groove (12) of the housing (10) is provided by the housing ring (13) and the opposite side flank (16) of the annular groove (12) of the housing (10) is provided by the cover (14), and the housing ring (13) has fastening devices (18) for fixing the housing (10) to a wall (100), in particular a bulkhead.

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