SLIDING RING SEAL ARRANGEMENT

Description

[0001] The present invention relates to a mechanical seal arrangement with improved support functions and sealing functions on a rear side of a sliding ring, as well as a reduction of a disturbance force transmission to the sliding ring, which leads to a reduced leakage at the sealing gap of the mechanical seal.

[0002] Mechanical seal assemblies are known in various designs from the prior art. In certain applications, particularly those involving toxic media, it must be ensured that the mechanical seal assembly is as leak-free as possible both during operation (i.e., with the sliding ring rotating) and when the machine to be sealed is at rest. This naturally also applies to other applications.

[0003] From US 2017 / 0146130 A1, a mechanical seal arrangement is known in which a spring-loaded preload ring has a ring area projecting axially towards the rear of the stationary sliding ring.

[0004] The object of the present invention is to provide a mechanical seal arrangement which, in all operating modes, provides a reliable seal and minimal or no leakage while being as simple and cost-effective to manufacture as possible.

[0005] This problem is solved by a mechanical seal arrangement having the features of claim 1. The dependent claims describe preferred embodiments of the invention.

[0006] The mechanical seal arrangement according to the invention, with the features of claim 1, has the advantage that a significant improvement in mechanical seal leakage and improved leakage stability is achieved. This is particularly advantageous because this improvement is achieved with a surprisingly simple adaptation of a retaining component arranged on the rear side of one of the sliding rings, thereby resulting in a significant reduction in leakage and an improvement in leakage stability. According to the invention, this is achieved by the mechanical seal arrangement comprising a mechanical seal with a rotating and a stationary sliding ring, wherein the sliding rings define a sealing gap between their sliding surfaces. Furthermore, the mechanical seal arrangement comprises a retaining component arranged on the rear side of one of the sliding rings.The retaining component has a base surface facing the rear of the sliding ring. The retaining component is, for example, a sliding ring carrier that holds the sliding ring. The base surface of the retaining component comprises an annular rib projecting from the base surface in the axial direction of the sliding ring seal, as well as a first and a second annular groove formed in the base surface. The two annular grooves and the annular rib are arranged concentrically to each other. The annular rib projects beyond the base surface of the retaining component by a predetermined amount, s. The projection of the annular rib beyond the base surface, which is perpendicular to a central axis of the sliding ring seal, is relatively small and, in particular, less than 1 mm. In the assembled state, the annular rib is in contact with the rear of the sliding ring to provide support on the rear of the sliding ring.The annular bridge is positioned between the first and second annular grooves. The first and second annular grooves are located directly adjacent to the annular bridge.

[0007] Thus, the clever design of the mechanical seal assembly according to the invention allows for a significantly improved sealing performance. The annular rib enables flexible contact between the retaining component and the back of the sliding ring. This allows for the compensation of disruptive forces that can occur during operation of the sliding ring due to temperature changes, especially temperature fluctuations to high temperatures, and changes in speed and pressure, without negatively affecting the flatness of the sliding surface of the sliding ring. The invention can be used particularly advantageously in mechanical seals where the sliding ring and the retaining component are made of different materials.The annular bridge can be adapted to the materials and / or the expected maximum and minimum temperatures as well as corresponding expected temperature gradients with regard to its flexibility, which is easily possible through the geometric design of the annular bridge according to the invention.

[0008] The retaining component with the two ring grooves and the ring-shaped web can be provided on both the rotating sliding ring and / or the stationary sliding ring.

[0009] Mechanical weakening of the holding component is prevented by the choice of the geometric dimensions of the ring-shaped bridge and the two ring grooves.

[0010] It is further preferred that the depth a', a of the first and second annular grooves is equal, or that the depth a' of the first annular groove is less than the depth a of the second annular groove. With equal depths, it can be ensured that geometrically identical conditions exist on both sides of the annular web. This also simplifies and significantly reduces the cost of manufacturing the annular grooves and the annular web.

[0011] Further preferredThe radial width t' of the first annular groove is equal to or different from the radial width t of the second annular groove. In particular, the groove widths of the first and second annular grooves are different. This has the advantage that the annular grooves can perform additional functions besides defining the annular web. Preferably, a secondary sealing element, in particular an O-ring or the like, is arranged in one of the annular grooves. Thus, one groove width of the two annular grooves is chosen to be relatively large. The other groove width can be chosen to be relatively small, since it is then only used to create the annular web in the base of the retaining component.

[0012] The retaining component is preferably a sliding ring carrier that overlaps the sliding ring. If the sliding ring is the rotating sliding ring, torque is preferably also introduced into the sliding ring via the retaining component.

[0013] Preferably, the retaining component has a ring-shaped section that extends radially inside the sliding ring. Consequently, this ring-shaped section forms a kind of inner sleeve for the retaining component, which can, for example, be arranged directly on a shaft or sleeve if the sliding ring is the rotating sliding ring. A third annular groove is preferably arranged in this additional ring-shaped section, in which an additional secondary sealing element or a centering aid for the sliding ring can be located.

[0014] Preferably, the retaining component with the ring-shaped bridge is made of a metal. The sliding ring on which the retaining component is arranged can also be made of a metal material or, alternatively, of a ceramic, in particular SiC or WC.

[0015] Preferably, the annular web projects beyond the base surface, which is perpendicular to the central axis of the mechanical seal, by a distance s of 0.1 mm ≤ s ≤ 0.5 mm. More preferably, the projection is 0.2 mm.

[0016] Preferably, the free web length I of the annular web extending from the shallower annular groove is in the range of 0.5 mm ≤ l ≤ 6 mm. The web length l is further preferably 1 mm ≤ l ≤ 2 mm and comprises the depth of the first annular groove a' and the projection s.

[0017] A depth a', a of the annular grooves extending from the base of the holding component is preferably in the range of 0.2 mm ≤ a' ≤ 6.5 mm and 0.2 mm ≤ a ≤ 6.5 mm. The depth a' is particularly preferably 2 mm.

[0018] A radial width t, t' of the annular grooves in a range of 0.1 mm to 7 mm is further preferred. If no secondary sealing element or the like is arranged in an annular groove must to keep the width of the ring groove as small as possible, preferably in a range of 0.1 mm to 2 mm.

[0019] According to a further preferred embodiment of the invention, the thickness h of the annular web is in a range of 0.2 mm ≤ h ≤ 1 mm. The thickness h is particularly preferably 0.4 mm.

[0020] Preferably, the ratio of the depth a', a of the first and second annular groove (8, 9) to the thickness h of the annular web 10 is in a range of 0.2 ≤ a' / h ≤ 15 and 0.2 ≤ a / h ≤ 15.

[0021] A further preferred ratio is that of the maximum free web length I of the annular web to a thickness h of the annular web in a range of 0.5 ≤ l / h ≤ 15. This ensures that the annular web has sufficient flexibility on the one hand and sufficient mechanical stiffness on the other.

[0022] A preferred embodiment of the invention is described in detail below with reference to the accompanying drawing. The drawing shows: Fig. 1 a schematic sectional view of a mechanical seal arrangement according to a first embodiment of the invention, Fig. 2 a schematic sectional view of a retaining component of the mechanical seal assembly of Figure 1 , Fig. 3 a schematic sectional view of another retaining component of the mechanical seal assembly of Figure 1 , Fig. 4a schematic, enlarged partial sectional view of the holding component of Figure 2 and Fig. 5 a schematic partial sectional view of an alternative design of a retaining component for a mechanical seal assembly.

[0023] The following refers to the Figures 1 to 4 A mechanical seal arrangement 1 according to a preferred embodiment of the invention is described in detail.

[0024] The mechanical seal assembly 1 comprises, as shown in Figure 1 A mechanical seal 2 with a rotating sliding ring 3 and a stationary sliding ring 4 is shown. A sealing gap 5 is defined between a sliding surface 3a of the rotating sliding ring 3 and a sliding surface 4a of the stationary sliding ring 4.

[0025] The mechanical seal 2 seals a product chamber 12 against an atmosphere 13 on a shaft 14. X-X denotes a central axis of the mechanical seal assembly.

[0026] The rotating sliding ring 3 is arranged on a first retaining component 6. The first retaining component 6 enables torque transmission from the shaft 14 to the rotating sliding ring 3. The first retaining component 6 is described in detail in Figure 2 shown.

[0027] The stationary sliding ring 4 is arranged on a housing 15. The stationary sliding ring 4 is pre-tensioned in the axial direction of the mechanical seal by means of a pre-tensioning element 17. A pin 16 serves as a torque input and ensures axial movement relative to the housing 15.

[0028] A second retaining component 7 is arranged on a rear side 4b of the stationary sliding ring 4 and is detailed as follows: Figure 3 evident.

[0029] The first retaining element 6, which holds the rotating sliding ring 3, has in particular a ring region 62, a radial region 61 and an overlapping region 63. A side of the first retaining element facing a rear side 3b of the rotating sliding ring 3 forms a base surface 60 of the first retaining element 6. The base surface 60 is arranged perpendicular to the central axis XX (see figure). Figure 2 ).

[0030] On the base surface 60, which faces the rear side 3b of the rotating sliding ring, an annular rib 10 projecting axially in the direction of the sliding ring seal, a first annular groove 8 and a second annular groove 9 are arranged. As can be seen in particular from Figure 2 As can be seen, the annular bridge 10 is arranged between the first annular groove 8 and the second annular groove 9. The two annular grooves 8, 9 and the annular bridge are arranged concentrically to each other.

[0031] What's next? Figure 2As can be seen, the annular web 10 projects an overhang s beyond the base surface 60 of the first retaining component 6 in the axial direction XX. As can be seen from the detail of Figure 4 As can be seen, the protrusion s is very small and preferably lies in a range of 0.1 mm to 0.5 mm.

[0032] The first and second annular grooves 8, 9 are thus arranged directly adjacent to the annular web 10. The mechanical stiffness of the annular web 10 depends on the depth a', a of the first and second annular grooves 8, 9 and the thickness h of the annular web 10. In this embodiment, the depth a' of the first annular groove 8 is less than the depth a of the second annular groove 9 (see figure). Figure 4 This defines a free bridge length I of bridge 10.

[0033] Furthermore, the width t' of the first annular groove 8 is smaller than the width t of the second annular groove 9. This allows the second annular groove 9 to accommodate a secondary sealing element 18. The first annular groove 8 is simply a recess to form the annular web 10 on the base surface 60 of the first retaining component 6. Therefore, the width t' of the first annular groove 8 is significantly smaller than the width t of the second annular groove 9.

[0034] Furthermore, a further annular groove 62a is formed in the ring area 62, in which a further secondary sealing element 19 is arranged. Alternatively, a centering element for the rotating sliding ring 3 can also be arranged here (see figure). Figure 2 ).

[0035] Thus, in the axial direction, the contact surface between the first retaining component 6 and the rotating sliding ring 3 is limited to an end region 10a of the annular web and the rear side 3b of the rotating sliding ring 3. This makes it possible to reduce disruptive forces that can occur between the components of the mechanical seal due to relative movements, which are caused in particular by changes in pressure, rotational speed, and / or temperature. Ultimately, this results in a significantly improved leakage stability of the mechanical seal assembly in a surprisingly simple way, especially under rising and falling temperatures or changing temperature gradients. Therefore, the robustness of the mechanical seal assembly against disruptive influences can be significantly increased.

[0036] The first retaining component 6 is preferably made of metal. The rotating sliding ring 3 can also be made of metal or, alternatively, of a ceramic material. The thickness h of the annular web 10 is preferably at most as wide as a minimum width t', t of one of the annular grooves 8, 9, in this embodiment t'.

[0037] The provision of the ring-shaped web 10 on the base surface 60 of the first retaining component 6 does not lead to a mechanical weakening of the first retaining component 6, since the depth a' of the first ring groove 8 is smaller than the depth a of the second ring groove 9 (cf. Figure 4 ). Thus, by making the arrangement of the rotating sliding ring 3 to the first retaining component 6 more flexible by providing the annular web 10, a significantly improved leakage behavior of the entire mechanical seal can be achieved.

[0038] In the first embodiment, the same arrangement is also formed on the rear side 4b of the stationary sliding ring 4. This is shown schematically in Figure 3 As shown, the second retaining element 7 is arranged on the rear side 4b of the stationary sliding ring 4. Like the first retaining element 6, the second retaining element 7 has a first annular groove 8, a second annular groove 9, and an annular web 10 arranged between the two annular grooves 8, 9. A base surface 70 of the second element 7 faces the rear side 4b of the stationary sliding ring 4. The two annular grooves 8, 9 and the annular web are again formed concentrically on the base surface 70. In this embodiment, the two annular grooves 8, 9 are provided solely to define the annular web 10. This means that neither of the two annular grooves 8, 9 needs to be relatively large to accommodate a secondary sealing element or the like.

[0039] Thus, in the first embodiment, the inventive idea is implemented both on the first retaining component 6 for the rotating sliding ring 3 and on the second retaining component 7 for the stationary sliding ring 4. The rear sides of the two sliding rings 3, 4 are therefore supported only on the end regions 10a of the annular webs 10. This ensures minimal leakage during operation in all operating situations of the mechanical seal assembly.

[0040] Figure 5 shows an alternative design of the first annular groove 9 of the first retaining component 6. Similar to the second retaining component 7, in Figure 5The annular web 10 is formed, for example, by two grooves, which form the first annular groove 8 and the second annular groove 9. The first and second annular grooves 8, 9 have the same cross-section, only being arranged on different radii, and define the annular web 10 between them. The depth a', a of the first and second annular grooves 8, 9 is the same. The width t', t of the annular grooves 8, 9 is also the same. This allows for cost-effective production of both annular grooves 8, 9 with the same tool.

[0041] In addition to the foregoing written description of the invention, explicit reference is hereby made to the graphic representation of the invention in the following for its supplementary disclosure. Figs. 1 to 5 Reference made to. Reference symbol list

[0042] 1 Mechanical seal assembly 2 Mechanical seal 3 Rotating sliding ring 3a Sliding surface 3b Back side 4 Stationary sliding ring 4a Sliding surface 4b Back side 5 Sealing gap 6 First retaining component 7 Second retaining component 8 First annular groove 9 Second annular groove 10 Annular web 10a End region 12 Product chamber 13 Atmosphere 14 Shaft 15 Housing 16 Pin 17 Preload device 18 Secondary sealing element 19 Secondary sealing element 60 Base area 61 Radial region 62 Annular region 62a Further annular groove 63 Overlap region 70 Base area X-X Central axis a, a' Depth of the annular groove starting from the base area h Thickness of the annular web in radial direction I Free web length s Projection of the annular web beyond the base area t, t' Width of the annular groove in radial direction

Claims

1. Mechanical seal arrangement, comprising • a mechanical seal (2) having a rotating slide ring (3) and a stationary slide ring (4), which define a sealing gap (5) between the sliding surfaces (3a, 4a) thereof, • a holding component (6, 7) which is arranged on a rear side (3b, 4b) of one of the slide rings (3, 4), • wherein the holding component (6, 7) comprises a main surface (60, 70) that faces the rear side (3b, 4b) of the slide ring (3, 4), • wherein the main surface (60, 70) comprises a rib (10) protruding from the main surface in the axial direction of the mechanical seal, • wherein the annular rib (10) protrudes beyond the main surface (60, 70) of the holding component (6, 7) by a projection s, • wherein the annular rib (10) is in contact with the rear side (3b, 4b) of the slide ring (3, 4) in order to provide a support on the rear side of the slide ring, characterized in that the main surface (60, 70) comprises a first annular groove (8) formed in the main surface, and a second annular groove (9) formed in the main surface, • wherein the first annular groove (8), the second annular groove (9) and the annular rib (10) are arranged concentrically to one another, • wherein the annular rib (10) is arranged between the first annular groove (8) and the second annular groove (9), and • wherein the first annular groove (8) and the second annular groove (9) are arranged directly adjacently to the annular rib.

2. Mechanical seal arrangement according to claim 1, wherein a depth a' of the first annular groove (8) is smaller than or equal to a depth a of the second annular groove (9), proceeding from the main surface (60, 70) of the holding component.

3. Mechanical seal arrangement according to any one of the preceding claims, wherein a width t' of the first annular groove (8) extending in the radial direction of the mechanical seal is smaller than or equal to a width t of the second annular groove (9).

4. Mechanical seal arrangement according to any one of the preceding claims, further comprising a secondary sealing element (18) which is arranged in one of the annular grooves.

5. Mechanical seal arrangement according to any one of the preceding claims, wherein the holding component (6, 7) and the annular rib (10) are produced from a metal material.

6. Mechanical seal arrangement according to any one of the preceding claims, wherein the projection s of the annular rib (10) is in a range of 0.1 mm ≤ s ≤ 0.5 mm; and / or wherein the rib length l of the annular rib (10), proceeding from the first annular groove (8), is in a range of 0.5 mm ≤ l ≤ 6 mm.

7. Mechanical seal arrangement according to any one of the preceding claims, wherein the depth a' of the first annular groove (8) and the depth a' of the second annular groove (9), proceeding from the main surface (60, 70), is in a range of 0.2 mm ≤ a' ≤ 6.5 mm and 0.2 mm ≤ a ≤ 6.5 mm.

8. Mechanical seal arrangement according to any one of the preceding claims, wherein a thickness h of the rib (10) is in a range of 0.2 mm ≤ h ≤ 1 mm.

9. Mechanical seal arrangement according to any one of the preceding claims, wherein a ratio of the depth a', a of the first and second annular groove (8, 9) to a thickness h of the annular rib (10) is in a range of 0.2 ≤ a' / h ≤ 15 and 0.2 ≤ a / h ≤ 15.

10. Mechanical seal arrangement according to any one of the preceding claims, wherein a ratio of a free rib length l of the annular rib to a thickness h of the annular rib is in a range of 0.5 ≤ l / h ≤ 15.