Mechanical ring and mechanical seal arrangement

Abstract

Mechanical ring of a mechanical seal comprising • an annular base body (30) with a sliding surface (3a) directed in the axial direction (XX) of the sliding ring, • a plurality of conveying grooves (5) formed in the sliding surface (3a), • wherein the conveying grooves (5) have a groove beginning (51) and a groove end (52), wherein the groove end (52) is spaced from an outer edge (32) of the sliding ring, and • a connecting groove (6) which is arranged in the sliding surface (3a) and connects at least two groove ends (52) of the conveying grooves (5) to one another, so that during operation of the sliding ring on the connecting groove (6) a distribution of pressure fields (7) at the groove ends (52) of the conveying grooves (5) is possible, • wherein the connecting groove (6) has a groove bottom (65) which has alternating deep regions (61) and raised regions (62) in the circumferential direction, wherein a distance of the deep regions (61) from the sliding surface (3a) is greater than a distance of the raised regions (62) from the sliding surface (3a).

Description

The present invention relates to a slide ring of a mechanical seal, and to a mechanical seal arrangement which, during operation, has reduced leakage and an increased service life of the slide rings.Mechanical seal arrangements are known from the prior art in different configurations. In order to increase a pressure in the sealing gap between the sliding surfaces of the sliding rings during operation, grooves are introduced into at least one of the sliding surfaces. The grooves are often provided as V-shaped grooves which provide a conveying action of blocking fluid in the sealing gap during operation. It has been found that, in particular at the V-shaped end of the grooves, pressure fields or pressure peaks of the barrier fluid can occur, which can lead to a corrugation of the slide rings. This results in an undesired increased leakage or, in extreme cases, also a contact of the wavy sliding surfaces, which can significantly reduce the service life of the sliding rings. Furthermore, CN 1 02 518 809 B shows a mechanical seal arrangement for sealing a medium with solid particles.It is therefore an object of the present invention to provide a sliding ring and a mechanical seal arrangement with a sliding ring which, with a simple structure and simple, cost-effective manufacture during operation, have a reduced ripple and thus a reduced leakage and an increased service life.This object is achieved by a mechanical seal ring having the features of claim 1 and a mechanical seal arrangement having the features of claim 12. The dependent claims each show preferred developments of the invention.The slide ring according to the invention of a mechanical seal arrangement having the features of claim 1 has the advantage that, during operation, a corrugation on the slide surfaces of the slide rings can be significantly reduced. This results in a significantly reduced leakage and also a significantly reduced risk of contacts of the sliding surfaces during operation. This reduces wear on the sliding surfaces, as a result of which a service life of the sliding rings is extended. Thus, longer maintenance intervals are possible and operators of mechanical seal assemblies can significantly reduce their operating costs. This is achieved according to the invention in that the slide ring of a mechanical seal has an annular base body with a slide surface directed in the axial direction of the slide ring. A plurality of conveying grooves are formed in the sliding surface. The conveying grooves have a groove start and a groove end, wherein the groove end is spaced apart from an outer edge of the sliding ring. In particular, the conveying grooves start at the inner edge of the sliding ring and are spaced apart from the outer edge of the sliding ring. Thus, the conveying grooves in the sliding surface of the slide ring are not continuous from the inner edge to the outer edge. Furthermore, the slide ring comprises a connecting groove in the sliding surface, which connects at least two groove ends of the conveying grooves to one another, in such a way that during operation of the slide ring at the connecting groove a distribution of pressure fields at the groove ends of the conveying grooves is made possible.Thus, the formation of pressure fields or pressure peaks at the groove ends of the conveying grooves, which is distributed in the region of the groove ends by the additional connecting groove, can be prevented.The connecting groove has a groove bottom which has regions which are alternately deep and elevated in the circumferential direction. The deep regions are thereby further away from the sliding surface than the raised regions.Preferably, the connecting groove is formed in such a way that the connecting groove is at least partially arcuate and runs in particular in the circumferential direction. This allows a particularly simple distribution of the pressure fields in the circumferential direction. Particularly preferably, the connecting groove has arcuate regions and rectilinear regions. The rectilinear regions are preferably arranged at or near the groove ends of the conveying grooves.The connecting groove is further preferably formed concentrically with respect to the edge of the sliding ring. As a result, the pressure fields can be distributed in a targeted manner concentrically with respect to the inner edge in the sealing gap. This enables a symmetrical distribution of the pressure fields and an improved performance of the mechanical seal.Particularly preferably, the connecting groove is designed to be completely closed in its circumference as a ring and connects all groove ends of all conveying grooves to one another. This makes it possible to ensure reliable distribution of the pressure fields at the groove ends of the conveying grooves during operation. In the optimum case, a pressure field of reduced volume, which is continuously formed continuously in the circumferential direction, with particularly reduced leakage, results.According to an alternative embodiment of the invention, the connecting groove has a multiplicity of partial connecting grooves, each partial connecting groove connecting at least two groove ends, in particular three groove ends, of conveying grooves to one another. This also allows distribution of pressure fields at the groove ends.According to a further preferred embodiment of the invention, at least one of the conveying grooves has the groove start at an inner edge of the sliding ring. In other words, the conveying groove begins at the inner periphery of the sliding ring. Particularly preferably, all the conveying grooves begin at the inner edge of the sliding ring.According to an alternative embodiment of the invention, the conveying grooves are formed in such a way that the groove starts of the conveying grooves start alternately at the inner edge of the sliding ring in the circumferential direction and are arranged at a distance from the inner edge. Thus, conveying grooves are provided alternately in the circumferential direction, which start from the inner edge and start at a distance from the inner edge. As a result, the creation of pressure fields can be influenced by a corresponding selection of the distance of the groove ends, which are arranged at a distance from the inner edge.Particularly preferably, the groove bottom of the connecting groove is formed in such a way that the deep regions of the groove bottom are arranged at openings of the groove ends on the connecting groove. Thus, at the openings of the groove ends, an increased space results through the deep regions of the connecting groove, which facilitates a pressure distribution of the pressure fields at the groove ends.The pressure fields are three-dimensional regions in which the barrier fluid is present at other regions in the sealing gap under an increased pressure compared to the pressure of the barrier fluid.Particularly preferably, the groove bottom of the connecting groove is formed wave-like with deep regions and raised regions arranged alternately with the circumferential directions. Particularly preferably, the groove bottom is formed with waves of sinusoidal cross section. This makes it possible to achieve a uniform configuration of the groove bottom, wherein a wavelength of a sinusoidal wave of the groove bottom corresponds to a distance in the circumferential direction of the groove ends.According to an alternative embodiment of the invention, the groove bottom of the connecting groove is saw-tooth-like. As a result, the groove bottom has a saw tooth shape in section. A tip spacing of adjacent saw teeth of the groove bottom in the circumferential direction is preferably of the same length as a spacing of mutually adjacent groove ends of two conveying grooves in the circumferential direction. The tips of the saw teeth are preferably rounded in order to improve a flow behavior of the blocking fluid in the connecting groove.Further preferably, a transition between the conveying grooves and the connecting groove at the mouth of the conveying grooves in the connecting groove is configured to be edge-free.Particularly preferably, the connecting groove is formed with a constant groove width in the radial direction. This has advantages in terms of production technology and enables a sufficient volume of the connecting groove for receiving barrier fluid from the pressure fields at the groove ends of the conveying grooves.Further preferably, the conveying grooves also have a constant groove width.According to a further preferred embodiment of the invention, all the conveying grooves have a geometrically identical cross section. In particular, all the conveying grooves have a constant depth or a constant width. The conveying grooves are preferably formed spirally in the sliding surface.Further preferably, a distance of an outer edge of the connecting groove from the outer edge of the sliding ring is smaller than a distance of the inner edge of the connecting groove from the inner edge of the sliding ring.The present invention further relates to a mechanical seal arrangement having a mechanical seal ring according to the invention. The slide ring according to the invention of the mechanical seal arrangement is preferably the rotating slide ring. It should be noted that it is also possible that a corresponding configuration of conveying grooves and connecting grooves as described above can be provided both in the rotating and in the stationary sliding ring. Preferably, the design of the conveying grooves and the connecting grooves in the rotating and stationary sliding ring is geometrically the same.Preferred embodiments of the invention will be described in detail below and with reference to the accompanying drawings. In the drawing, the following is: FIG. 1 shows a schematic sectional view of a mechanical seal arrangement with a sliding ring according to a first preferred exemplary embodiment of the invention, FIG. 2 shows a schematic plan view of a sliding surface of the rotating sliding ring of the mechanical seal arrangement of FIG. 1, FIG. 3 is a schematic sectional view taken along the line III--III of FIG. 2, FIG. 4 shows a schematic partial view of the sliding ring of the mechanical seal arrangement of FIG. 1 with a schematically illustrated pressure field, FIG. 5 shows a partial view of the slide ring of the mechanical seal arrangement with a distributed pressure field, FIG. 6 shows a schematic sectional view corresponding to the sectional view of FIG. 3 of a sliding ring according to a second exemplary embodiment, FIG. 7 shows a schematic plan view of a slide ring of a slide ring seal according to a third exemplary embodiment of the invention, FIG. 8 shows a schematic plan view of a slide ring of a slide ring seal according to a fourth exemplary embodiment of the invention, and FIG. 9 shows a schematic plan view of a slide ring of a slide ring seal according to a fifth exemplary embodiment of the invention.In the following, a mechanical seal arrangement 1 is described in detail with reference to FIGS. 1 to 5.As can be seen from FIG. 1, the mechanical seal arrangement 1 comprises a mechanical seal 2 with a rotating slide ring 3 and a stationary slide ring 4. the rotating slide ring 3 has a first slide surface 3 aand the stationary slide ring 4 has a second slide surface 4 a. A sealing gap 2a is formed between the two sliding surfaces 3a, 4a. The mechanical seal 2 seals a product space 11 and an atmospheric space 12.The rotating slide ring 3 is connected to a shaft 17 by means of a slide ring carrier 13. The stationary slide ring 4 is prestressed by means of a prestressing device 14, which is located on a rear side 41 of the stationary slide ring 4 and prestresses the latter in the axial direction X-X with respect to the rotating slide ring 3. The stationary slide ring 4 is axially movable on a sleeve 16. Reference numeral 15 denotes a housing.The rotating slide ring 3 can be seen in detail from FIGS. 2 and 3. FIG. 2 shows a plan view of the sliding surface 3 aof the rotating sliding ring 3.As shown in FIG. 2, a plurality of feed grooves 5 are formed in the sliding surface 3a of the rotary slide ring 3. During operation of the mechanical seal 2, the conveying grooves 5 make it possible to convey sealing fluid within the sealing gap 2 a.The conveying grooves 5 are all constructed geometrically identically and have a groove beginning 51 and a groove end 52. The groove start 51 is provided on an inner periphery 31 of the rotating slide ring. The groove end is arranged at a radial distance from an outer periphery 32 of the rotating sliding ring 3.As can be seen from FIG. 2, a connecting groove 6 is also provided, which connects all groove ends 52 of the conveying groove 5 to one another. The connecting groove 6 is annular and is arranged concentrically with the inner periphery 31 and the outer periphery 32. The connecting groove 6 is provided closer to the outer periphery 32 than to the inner periphery 31 in the radial direction.The connecting groove 6 has a constant groove width.The conveying grooves 5 begin at the inner periphery 31 and open into the connecting groove 6.The feed grooves 5 and the connecting groove 6 are formed in the base body 30 of the rotating slide ring 3.FIG. 3 shows a sectional view of the connecting groove 6 along the line III-III of FIG. 2 From the cross section of the connecting groove 6 of FIG. 3, it can be clearly seen that the connecting groove 6 has a groove bottom 65 which is formed in a wave shape. In this exemplary embodiment, the groove bottom 65 is provided in a sinusoidal manner. In this case, the groove bottom 65 has deep regions 61 and elevated regions 62. As can be seen from FIG. 3, however, the elevated regions 62 are somewhat spaced apart from the sliding surface 3 aof the sliding ring 3, such that the connecting groove 6 is present in a completely annular manner in the circumferential direction.As can be further seen from FIG. 3, the deep regions 61 are arranged at the mouth regions of the conveying grooves 5 into the connecting groove 6. In this case, exactly one elevated region 62 is provided between two adjacent groove ends 52 (cf. FIG. 2 ).The wave-shaped groove base 65 is provided in such a way that, starting from a first deep region 61 on a first conveying groove 5, the groove base 65 has a wave which extends as far as an adjacent further conveying groove 5 (cf. FIG. 3 ).During operation of the mechanical seal 2, when the rotating slide ring 3 rotates in the direction of rotation A, pressure fields 7 form in the sealing gap between the sliding surfaces 3 a, 4 aof the slide rings at the groove ends 52 of the conveying grooves 5. A pressure field 7 is a three-dimensional three-dimensional three-dimensional structure without a defined shape, in which an increased volume of barrier fluid can be under high pressure. Such pressure fields 7 can cause a corrugation on the sliding surfaces of the sliding rings during operation.The measure according to the invention of connecting groove ends 52 of the conveying grooves 5 by means of the connecting groove 6 now results in a distribution of pressure fields 7 present, as schematically illustrated in FIG. 5. The distributed printing field is identified by reference numeral 7'. The connecting groove 6 can thus distribute the blocking fluid accumulated at the groove ends 5 in the circumferential direction, so that a height of the pressure field between the sliding surfaces is reduced and thus the risk of corrugation forming at the sliding surfaces is significantly reduced.Since the connecting groove 6 extends concentrically to the inner and outer peripheries in the circumferential direction, the pressure field 7 is also distributed in the circumferential direction. Depending on a rotational speed and / or a distance from adjacent groove ends 52 of the conveying grooves, a continuous, distributed pressure field 7' can be produced during operation, since a distribution of the pressure fields takes place at each groove end 52. As a result, an additional pressure barrier against a leakage of medium from the product space 11 in the direction of the atmosphere space 12 can be achieved within the sealing gap 2 a.Thus, by the groove arrangement including the feed grooves 5 and the connecting groove 6 in the sliding surface 3 aof the rotating slide ring 3, wave formation on the sliding surfaces can be prevented. This results in a significantly reduced leakage during operation and a significantly extended service life, since contacts on the sliding surfaces are minimized due to reduced no longer present corrugation on the sliding surfaces, whereby wear of the sliding rings is minimized.FIG. 6 shows a sectional view of a slide ring of a mechanical seal arrangement according to a second initial example of the invention. Identical or functionally identical parts are denoted by the same reference numerals as in the first exemplary embodiment.As can be seen from FIG. 6, in the second exemplary embodiment, the groove base 65 of the connecting groove 6 is formed differently. The groove bottom 65 is provided in the second exemplary embodiment in the manner of a saw tooth. In this case, the groove bottom 65 has raised regions 62 in the form of peaks and deep regions 61 in the form of valleys. The deep regions are disposed immediately adjacent to the raised regions 62. Starting from a deep region 61, a ramp 63 is provided, which runs from the deep region 61 to the elevated region 62. The ramp 63 is preferably provided with a constant gradient. As can be seen widely from FIG. 6, the conveying grooves 5 end directly at the deep region 61 of the saw-tooth-like groove base 65. the distribution of the pressure fields at the groove ends is here correspondingly as described in the first exemplary embodiment, so that reference can be made to the description given there.FIG. 7 shows a slide ring of a mechanical seal arrangement according to a third exemplary embodiment of the invention. Identical or functionally identical parts are again denoted by the same reference numerals as in the preceding exemplary embodiments.As can be seen from FIG. 7, which shows a plan view of the sliding surface 3 aof the rotated sliding ring 3, the connection groove of the third exemplary embodiment is embodied differently from the preceding exemplary embodiments. As shown in FIG. 7, a plurality of partial communication grooves 60 are provided. A partial connecting groove 60 connects exactly two adjacent conveying grooves 5 in the region of the groove ends 52 of the conveying grooves 5, respectively. As can be seen from FIG. 7, a partial connecting groove starts in front of a first groove end of a conveying groove 5 and extends beyond a groove end of an adjacent second conveying groove 5. Between the part connecting grooves 60, sliding surface portions 64 are provided in the circumferential direction, which form a usual sliding surface portion of the sliding surface 3 aof the rotating slide ring 3. The partial connecting grooves 60 are again formed in a sinusoidal manner with deep regions 61 at the groove ends of the conveying grooves 5 and exactly one elevated region 62 between two adjacent deep regions 61. Thus, the third embodiment substantially corresponds to the first embodiment with the difference that the connecting groove 6 is interrupted and the partial connecting grooves 60 each connect exactly two adjacent conveying grooves 5 to one another.With regard to the third exemplary embodiment, it should be noted that it is of course also possible for the partial connecting grooves 60 to connect more than two conveying grooves 5, for example three or four conveying grooves, to one another. Otherwise, this exemplary embodiment corresponds to the preceding exemplary embodiment, so that reference can be made to the description given there.FIG. 8 shows a sliding ring according to a fourth exemplary embodiment of the invention. The fourth exemplary embodiment substantially corresponds to the first exemplary embodiment, wherein, in contrast to the first exemplary embodiment, the conveying grooves 5 are formed differently in the fourth exemplary embodiment. As can be seen from FIG. 8, the conveying grooves 5 are arranged alternately in the circumferential direction in such a way that one conveying groove begins at an inner circumference 31 of the sliding ring at a groove start 51 aand an adjacent conveying groove has a groove start 51 bwhich is spaced apart from the inner circumference 31 of the sliding ring. As can be seen from FIG. 8, in this exemplary embodiment, all the groove starts 51 b, which are spaced apart from the inner circumference, are arranged on a common diameter D 1. It should be noted, however, that it is also possible for the groove starts 51 b, which are spaced apart from the inner periphery 31, to begin on different diameters. Due to the different design of the groove beginnings 51 a, 51 bin the fourth exemplary embodiment, in particular the pressure fields generated during operation can be specifically influenced.FIG. 9 shows a sliding ring of a mechanical seal arrangement according to a fifth exemplary embodiment of the invention. The fifth exemplary embodiment corresponds substantially to the third exemplary embodiment, wherein, in contrast to the third exemplary embodiment, in the fifth exemplary embodiment, the partial connecting grooves 60 are configured differently. In the fifth embodiment, the part connecting grooves 60 have a linear portion 60 aand an arc-shaped portion 60 b. The partial connecting grooves 60 again connect two mutually adjacent conveying grooves 5 in each case, the rectilinear partial region 60 abeing arranged at a groove end 52 of one of the conveying grooves 5 connected by the connecting groove 6. The arcuate portion 60b is part of a spiral centered on the central axis of the slide ring. The part connecting grooves 60 of the fifth exemplary embodiment are each provided geometrically identically.In addition to the above written description of the invention, for the purpose of supplementary disclosure thereof, explicit reference is hereby made to the graphical representation of the invention in the figures.List of reference characters1 Mechanical seal arrangement 2 Mechanical seal 2 a Dicht gap 3 Rotating mechanical seal 3 aFirst sliding surface 4 Stationary mechanical seal 4 aSecond sliding surface 5 Conveying groove 6 Connecting groove 7 Pressure field 7' Distributed pressure field 11 Product space 12 Atmospheric space 13 Mechanical seal carrier 14 Prestressing device 15 Housing 16 Sleeve 17 Shaft 30 Base body 31 Inner periphery 32 Outer periphery 41 Rear side of the stationary mechanical seal 51 Groove start 51 a Groove start at the inner periphery 51 b Groove start spaced apart from the inner periphery 52 Groove end 60 Part-connecting groove 60 a Geradlinig portion of the part-connecting groove 60 b Bogenförmig portion 61 Deep portion 62 Elevated portion 63 Ramp 64 Sliding surface portion 65 Groove base A Direction of rotation D 1 Diameter, On the groove beginning spaced from the inner periphery are X-X axial directions

Claims

Slide ring of a slide ring seal comprising • an annular base body (30) having a slide surface (3a) directed in the axial direction (X-X) of the slide ring, • a plurality of conveying grooves (5) formed in the slide surface (3a), • wherein the conveying grooves (5) have a groove start (51) and a groove end (52), wherein the groove end (52) is spaced apart from an outer edge (32) of the slide ring, and • a connecting groove (6) which is arranged in the slide surface (3a) and connects at least two groove ends (52) of the conveying grooves (5) to one another, such that during operation of the slide ring at the connecting groove (6) a distribution of pressure fields (7) at the groove ends (52) of the conveying grooves (5) is made possible, • wherein the connecting groove (6) has a groove bottom (65), which has deep regions (61) and raised regions (62) alternately in the circumferential direction, wherein a distance of the deep regions (61) from the sliding surface (3a) is greater than a distance of the raised regions (62) from the sliding surface (3a).Slide ring according to claim 1, wherein the connecting groove (6) extends at least partially in an arc shape, in particular in the circumferential direction of the slide ring.The sliding ring according to claim 2, wherein the connecting groove (6) extends concentrically to the inner and outer edge (31, 32) of the sliding ring.Slide ring according to one of the preceding claims, wherein the connecting groove (6) is formed so as to be completely circumferential and connects all groove ends (52) of the conveying grooves (5) to one another.The sliding ring according to any one of claims 1 to 3, wherein the connecting groove comprises a plurality of partial connecting grooves (60), each partial connecting groove (60) connecting at least two groove ends (52) of conveying grooves (5) to each other.Slide ring according to one of the preceding claims, wherein at least one conveying groove (5) has the groove start (51) at an inner edge (31) of the slide ring.Slide ring according to claim 6, wherein all the conveying grooves (5) have the groove start at an inner edge (31) of the slide ring or wherein the conveying grooves (5) have the groove start at the inner edge (31) and at a distance from the inner edge (31) alternately in the circumferential direction.Slide ring according to Claim 1, wherein the deep regions (61) of the groove base (65) are arranged at openings of the groove ends (52) on the connecting groove (6).Sliding ring according to claim 1 or 8, wherein the groove bottom (65) is formed in a wave-like manner with deep regions (61) and elevated regions (62) arranged alternately in the circumferential direction.Slide ring according to one of claims 1 or 8, wherein the groove bottom (65) is saw-tooth-like.Slide ring according to one of the preceding claims, wherein an edge-free transition is provided between the conveying grooves (5) and the connecting groove (6) in the region of the groove end (52), or - wherein the connecting groove (6) has a constant groove width, or - wherein the conveying grooves (5) all have a geometrically identical cross section.Mechanical seal arrangement comprising a mechanical seal (2) with a mechanical seal according to one of the preceding claims.The mechanical seal assembly of claim 12, wherein the sliding ring is the rotating sliding ring (3).Mechanical seal arrangement according to claim 12 or 13, wherein the mechanical seal (2) is a gas-lubricated mechanical seal.

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