EP3405706A1

EP3405706A1 - Mechanical seal assembly having reduced leakage

Info

Publication number: EP3405706A1
Application number: EP16813236.3A
Authority: EP
Inventors: Johannes Pröbstl; Berthold Schulten; Ulrich Schubert
Original assignee: EagleBurgmann Germany GmbH and Co KG
Current assignee: EagleBurgmann Germany GmbH and Co KG
Priority date: 2016-01-21
Filing date: 2016-12-19
Publication date: 2018-11-28
Also published as: WO2017125227A1; DE102016200818B4; DE102016200818A1

Abstract

The present invention relates to a mechanical seal assembly, comprising a mechanical seal (2), which has a stationary face seal ring (3) and a rotating face seal ring (4) that define a sealing gap (5) therebetween, and comprising a stationary throttle ring (14), which is arranged on an outer circumference of the rotating face seal ring (4), wherein an annular gap (15) extending in the axial direction is present between the throttle ring (14) and the rotating face seal ring (4), and wherein the rotating face seal ring (4) is produced from a material that is harder than a material of the throttle ring (14).

Description

Mechanical seal assembly with reduced leakage

description

The present invention relates to a mechanical seal assembly with a reduced leakage, in particular on an annular gap located in the radial direction of a sliding ring.

Mechanical seal assemblies are known in the prior art in various configurations. During operation, in addition to leakage via a sealing gap between a rotating and a stationary sliding ring, leakage at radial annular gaps or at a rear side of the sliding rings can also occur. In this case, a metallic mechanical seal carrier is usually used, which contacts the seal ring to be sealed at the rear and engages over an outer circumference in the axial direction, as known, for example, from DE 10 2014 203 336 A1. In this document, the rotating seal ring is overlapped by such, in section L-shaped Gleitringträger. A bellows ensures an axial mobility of the rotating seal ring to allow repositioning of the sliding ring upon movement of the shaft. In particular, when sealing hot gaseous media, however, a leakage between the slide ring carrier and the sliding ring on the back of the slip ring may occur or leakage at a radial annular gap on the outer periphery of the rotating seal ring.

It is therefore an object of the present invention to provide a mechanical seal assembly, which allows a simple construction and simple, cost manufacturability improved sealing, in particular on a radial annular gap of a sliding ring of a mechanical seal. This object is achieved by a Gieitringdichtungsanordnung with the features of claim 1. The dependent claims show preferred developments of the invention.

The Gieitringdichtungsanordnung invention with the features of claim 1 allows a reduced leakage at a radial peripheral side of a sliding ring. The Gieitringdichtungsanordnung includes a mechanical seal with a stationary and rotating seal ring, which define a sealing gap between them and a stationary throttle ring. The throttle ring is disposed on an outer circumference of the rotating seal ring such that there is an annular gap extending in the axial direction between the rotating seal ring and the throttle ring. In this case, the rotating seal ring is made of a material which is harder than the material of the throttle ring. The choice of the softer material for the throttle ring, in particular an accurate assembly of the throttle ring is possible, so that the annular gap between the throttle ring and rotating seal ring can be accurately adjusted and has a very small radial dimension.

The annular gap between the throttle ring and the rotating seal ring is preferably less than or equal to 0.2 mm. Particularly preferably, the annular gap is in a range between 0.08 mm to 0.2 mm and in particular between 0.05 mm to 0.15 mm and is in particular 0.1 mm.

The annular gap is preferably a Kohlering, which consists of 100% carbon.

More preferably, the throttle ring is in the axial direction of the Gieitringdichtungsanordnung on a rear side of the rotating seal ring with a predetermined projection on the back in the axial direction. The predetermined supernatant is preferably at most 0.15 mm, and more preferably in a range from 0.05 to 0.15 mm.

More preferably, the throttle ring in the axial direction to an extent which is longer than an extension of the rotating seal ring in the axial direction. Particularly preferred is the throttle ring over to both axial sides of the rotating seal ring. Preferably, the throttle ring covers the sealing gap between the slip rings. According to a further preferred embodiment of the present invention, the throttle ring is shrunk into an outer sleeve of the mechanical seal assembly. By providing the shrinkage connection between the outer sleeve and the throttle ring, a particularly accurate positioning of the throttle ring can be made possible. More preferably, the mechanical seal assembly further comprises a shaft seal having a first and second sealing lip. The shaft seal seals with the two sealing lips preferably on a common component, in particular a shaft sleeve from.

More preferably, the mechanical seal further comprises a slip ring carrier, which supports the stationary seal ring. In Gleitringträger a leakage channel for discharging leakage is also preferably provided. The leakage channel preferably leads from a gap between the mechanical seal and the shaft seal.

According to a further preferred embodiment of the present invention, the mechanical seal assembly further comprises a biasing member which exerts an axial bias on the stationary seal ring. The biasing element is preferably a bellows, in particular a metal bellows. The bellows is preferably connected to a biasing ring, in particular by means of a welded connection, which contacts a rear side of the stationary sliding ring. Between the biasing ring and the stationary seal ring, a contact region is particularly preferably provided, which is provided by a first contact surface on a rear side of the stationary seal ring and a second contact surface on the biasing ring. The stationary seal ring is preferably made of a material having a lower hardness than a material of the biasing ring. The stationary seal ring is particularly preferably a Kohlering. The biasing ring is preferably made of a metal material.

The first and second contact surfaces are further preferably processed by means of fine machining methods and have a low average roughness, in particular in the range of 0.01 μm to 0.5 μm, preferably 0.1 μm to 0.3 μm, and in particular 0.5 μm , In order to achieve a high surface pressure in the contact region between the two contact surfaces, the first contact surface is preferably smaller than the second contact surface.

More preferably, the first contact surface is provided on the stationary seal ring on an annular shoulder projecting in the axial direction of the slip ring sealing arrangement.

Furthermore, a first average diameter of the contact region between the first and second contact surfaces is preferably equal to a second average diameter at the sliding surfaces of the two sliding rings. Furthermore, a third average diameter of the bellows is preferably smaller than the first mean diameter of the contact region. In this way, in particular, it can be achieved that a hydraulic load is present at the contact region and the area between the two sliding surfaces is hydraulically relieved.

The Gieitringdichtungsanordnung is particularly preferably provided as a pre-assembly in which a partial or complete pre-assembly is possible, so that a mounting at a site of the Gieitringdichtungsanordnung is then significantly easier.

Hereinafter, the invention will be described in detail with reference to the accompanying drawings. In the drawing is:

Fig. 1 is a schematic sectional view of an inventive

Gieitringdichtungsanordnung,

Fig. 2 is a schematic, perspective sectional view of

Gieitringdichtungsanordnung of Fig. 1, and

Fig. 3 is a schematic, enlarged view of the mechanical seal of

Gieitringdichtungsanordnung of Figures 1 and 2. Hereinafter, with reference to Figs. 1 to 3, a Gieitringdichtungsanordnung 1 according to a preferred embodiment of the invention described in detail.

As is apparent from Figs. 1 and 2, the Gieitringdichtungsanordnung 1 comprises a mechanical seal 2 with a first seal ring 3 and a second seal ring 4. In this embodiment, the first seal ring 3, the stationary seal ring and the second sliding ring 4 of the rotating seal ring. Between the two sliding rings, a sealing gap 5 is present, which is limited by the sliding surfaces of the two sliding rings 3, 4.

The mechanical seal 2 seals a media side 40 to a side at which a different pressure level, in particular ambient pressure, prevails. In this embodiment, the seal is made to a storage space 21 which is filled with oil to lubricate a bearing 20.

The mechanical seal assembly 1 of this embodiment is further formed as a pre-assembly, d. H. it is one, at least partially, pre-assembly possible, so that later installation at the site is facilitated.

The mechanical seal assembly 1 seals on a shaft 18, which drives a rotating member 19, from.

The second seal ring 4 (rotating seal ring) is arranged on a shaft sleeve 10, which is connected to the shaft 18. The mechanical seal assembly 1 is installed in a housing member 31.

Furthermore, an outer sleeve 23 is provided, which allows easy handling of the subassembly.

A slide ring carrier 13 holds the first slide ring 3 (stationary slide ring). The Gleitringträger 13 also receives a biasing element, which is designed as a bellows 8 ,. The bellows 8 exerts a biasing force F in the direction of the first sliding ring 3 (see Fig. 1).

The bellows 8 is fixed to a biasing ring 7, preferably by means of a welded connection. An opposite end of the bellows 8 is fixed to a support ring 17, which is supported on the slip ring carrier 13. Between the first seal ring 3 and the biasing ring 7, a contact region 50 is provided. In this case, a first contact surface 11 is provided on a rear side 6 of the first sliding ring 3 and a second contact surface 12 is provided on a side of the pretensioning ring 7 directed toward the first sliding ring (see FIG. 3).

The mechanical seal assembly 1 further comprises a shaft seal 9, which has a first sealing lip 91 and a second sealing lip 92nd having. The two sealing lips 91, 92 in this case seal on a same component, in this embodiment, on the shaft sleeve 10. The first sealing lip 91 seals against one of the media side 40 via column to the shaft seal 9 arrived medium and the second sealing lip 92 seals against the oil in the storage room 21 from. The shaft sealing ring 9 is supported on the outer sleeve 23 via an intermediate component 90.

In the slip ring carrier 13, a leakage channel 30 is also provided, via which, as indicated in Fig. 1 by the arrow L, leakage, which can get into an intermediate space 70 between the mechanical seal 2 and the shaft seal 9, can be dissipated. A leak can pass from the media side 40 via a media gap 22 between the rotating member 19 and the housing member 31 via an annular gap 15 and the sealing gap 5 between the two slip rings 3, 4 to the gap 70.

The annular gap 15 is provided between an outer circumference of the second sliding ring 4 and a throttle ring 14. The throttle ring 14 is fixed by means of a shrink connection 80 on the inner circumference of the outer sleeve 23. The throttle ring 14 is made of a material which has a lower hardness than the second seal ring. The throttle ring 14 is preferably provided as Kohlering. As can be seen from FIG. 3, the contact area 50 on the rear side 6 of the first sliding ring 3 and the pretensioning ring 7 is provided with as close a contact as possible without a gap between the first sliding ring 3 and the pretensioning ring 7 in order to avoid any leakage through this path into the Allow gap 70. For this purpose, the first contact surface 11 and the second contact surface 12 are processed by means of fine machining measures. This results in a very small roughness depth of the first contact surface 11 on the first slide ring 3 and the second contact surface 12 on the biasing ring 7. The roughness depth is at both contact surfaces about 0.15 pm.

As can be seen from FIG. 3, the first contact surface 11 is provided on an annular shoulder 60 on the rear side 6 of the first sliding ring 3. The annular shoulder 60 is formed protruding in the axial direction XX of the mechanical seal assembly in the direction of the biasing ring 7. Furthermore, a surface of the first contact surface 11 is significantly smaller than a surface of the second contact surface 12. As a result, the bias voltage F of the bellows 8 can be exerted on a small annular surface of the first contact surface 11, so that a high surface pressure in the contact region 50 is achieved. The biasing ring 7 is further formed of a material having a greater hardness than a material of the first slide ring 3. Preferably, the slip ring 3 is a carbon ring 100% made of carbon, and the bias ring 7 is a steel ring.

Due to the different hardnesses between the two contact partners, a seal in connection with the biasing force F, which acts on the contact region 50, is further increased.

In order to avoid tilting of components of the mechanical seal assembly as far as possible, the contact region 50 is preferably arranged on a first average diameter D1, which is equal to a second average diameter D2 on the sliding surfaces of the two seal rings 3, 4. A third average diameter D3 on the bellows 8 is smaller than the first and second diameter D1, D2. The three diameters D1, D2 and D3 are shown schematically in FIG.

Thus, a reduced leakage into the gap 70 can be achieved by the improved seal on the back 6 of the first slide ring 3. Due to the different materials between the first seal ring 3 and the biasing ring 7, a further improved sealing can be made possible.

Furthermore, by providing the throttle ring 14, a smallest possible annular gap 15 can be obtained on the outer circumference of the second sliding ring 4. The annular gap 15 has a width of less than or equal to 0.2 mm, in particular in a range of about 0.08 mm to 0.2 mm, preferably 0.1 mm to 0.15 mm.

The arrangement of the contact region 50 on the first average diameter D1, which is greater than the third average diameter D3 on the bellows 8, results in a hydraulic load on the rear side 6 of the first sliding ring 3. By arranging the contact region 50 on the same first mean diameter D1 as the second average diameter D2 between the slip rings 3, 4, however, results in a hydraulic relief at sealing gap. 5 O

The first slide ring 3 made of, for example, coal can be loosely inserted into the slide ring carrier 13 and centered on the slide ring carrier 13 via a small radial gap.

The provision of the softer throttle ring 14, which is also made of carbon, also prevents excessive leakage through the media gap 22 and the annular gap 15 to the mechanical seal 2. The always present during operation leakage over the sealing gap 5 between the two slip rings 3, 4 can be minimized and possibly discharged through the leakage channel 30.

The mechanical seal 2 and the shaft sealing ring 9 and the biasing element 8 can be arranged together in a preassembly, so that an assembly of the mechanical seal assembly 1 can be facilitated.

As can be seen in particular from FIG. 3, the throttle ring 14 projects in the axial direction XX about a projection 16 via a rear side 41 of the second sliding ring 4. This prevents a contact between the rotating member 19 and the second seal ring 4 occurs during shaft movements and / or Wellenauslenkungen, so that the second seal ring 4 is protected by the throttle ring 14 from such contacts. The supernatant 16 in the axial direction is less than or equal to 0.15 mm and is in particular in a range between 0.05 and 0.15 mm.

"

Reference numerals! Iste

1 gasket assembly

2 mechanical seal

3 first sliding ring (stationary sliding ring)

4 second sliding ring (rotating sliding ring)

5 sealing gap

6 Rear side of the first sliding ring

7 preload ring

8 pretensioning element (bellows)

9 shaft seal

10 shaft sleeve

11 first contact surface

12 second contact surface

13 slide ring carrier

14 throttle ring

15 annular gap

16 supernatant

17 support ring

18 wave

19 rotating component

20 bearings

21 storeroom filled with oil

22 media gap

23 outer sleeve

30 leakage channel

31 housing component

40 media page

41 back of the second sliding ring 50 contact area

60 ring heel

70 space

80 shrink connection

90 intermediate component

91 first sealing lip , ,

10

92 second sealing lip

L leakage removal

F bias

X-XAxialrichtung

D1 first average diameter at the contact area D2 second average diameter of the sliding surfaces D3 third average diameter of the bellows

Claims

claims

1 . Mechanical seal assembly comprising:

- A mechanical seal (2) with a stationary seal ring (3) and a rotating seal ring (4), which define between them a sealing gap (5),

a stationary throttle ring (14) which is arranged on an outer circumference of the rotating sliding ring (4),

- Wherein between the throttle ring (14) and the rotating seal ring (4) an axially extending annular gap (15) is present, and

- Wherein the rotating seal ring (4) is made of a material which is harder than a material of the throttle ring (14).

2. Arrangement according to claim 1, characterized in that the annular gap (15) is less than or equal to 0.2 mm.

3. Arrangement according to one of the preceding claims, characterized in that the throttle ring (14) is a Kohlering.

4. Arrangement according to one of the preceding claims, characterized in that the throttle ring (14) in the axial direction (XX) of the mechanical seal assembly on a rear side (41) of the rotating seal ring (4) with a projection (16) in the axial direction over the rotating seal ring (16). 4) survives.

5. Arrangement according to claim 4, characterized in that the projection (16) is less than or equal to 0.15 mm.

6. Arrangement according to one of claims 4 or 5, characterized in that the throttle ring (14) in the axial direction (X-X) is longer than the rotating seal ring in the axial direction.

7. Arrangement according to claim 6, characterized in that the throttle ring (14) in the axial direction (XX) projects beyond the sealing gap (5).

8. Arrangement according to one of the preceding claims, further comprising an outer housing (23) on which the throttle ring (14) is fixed, wherein between the outer sleeve (23) and the throttle ring (14) is formed a shrink connection (80).

9. Arrangement according to one of the preceding claims, further comprising a shaft seal (9) having a first sealing lip (91) and a second sealing lip (92).

10. Arrangement according to one of the preceding claims, further comprising a slip ring carrier (13) which supports the stationary seal ring (3), wherein in the slip ring carrier (13) a leakage channel (30) is provided.

11. Arrangement according to one of the preceding claims, further comprising a biasing element (8), in particular a bellows, wherein the biasing element (8) exerts a bias (F) on the stationary seal ring (3).

12. The arrangement according to claim 11, characterized in that the stationary slide ring (3) on a rear side (6) has a first contact surface (11) and on the biasing ring (7) a second contact surface (12) is provided, which the first contact surface ( 11), wherein the stationary seal ring (3) is made of a material having a hardness which is smaller than a hardness of the material of the biasing ring (7).

13. Arrangement according to claim 12, characterized in that the first contact surface (11) on the stationary seal ring is smaller than the second contact surface (12) on the biasing ring (7).

14. Arrangement according to claim 12 or 13, characterized in that the first contact surface (11) is provided on a in the axial direction (X-X) projecting annular shoulder (60).

15. Arrangement according to one of claims 12 to 14, characterized in that a first average diameter (D1) of the contact region (50) between the first and second contact surface (11, 12) equal to a second average diameter (D2) on the sliding surfaces of Slip rings (3, 4).