MECHANICAL SEAL ASSEMBLY WITH IMPROVED SUPPORT OF AXIAL FORCES

The invention relates to a mechanical seal assembly (1) for sealing between a high-pressure region (8) and a low-pressure region (9) on a rotating component (7), comprising a mechanical seal (2) with a rotating slide ring (3) with a first slide surface (30) and a stationary slide ring (4) with a second slide surface (40), wherein a sealing gap (5) is defined between the slide surfaces (30, 40), a slide ring carrier (31) for the rotating slide ring (3), which is configured to connect the rotating slide ring (3) to the rotating component (7) in a rotationally fixed manner, wherein the slide ring carrier (31) comprises a sleeve region (32), and a force support arrangement (6), which is configured to support an axial force (F) acting on the mechanical seal assembly (1), wherein the force support arrangement (6) is arranged on an end face (32a) of the sleeve region (32) of the slide ring carrier (31), wherein the force support arrangement (6) comprises a clamping sleeve (60), a conical sleeve (61) and a split ring (62) with at least two segments (621, 622), wherein a conical connection with a first conical surface (60a) on the clamping sleeve (60) and a second conical surface (61a) on the conical sleeve (61) is formed between the clamping sleeve (60) and the conical sleeve (61), and wherein the clamping sleeve (60) bears against the end face (32a) of the sleeve region (32) and the conical sleeve (61) bears against a side surface (62a) of the divided ring (62).

The present invention relates to a mechanical seal assembly for sealing between a high-pressure region and a low-pressure region on a shaft with improved support of axial forces that may act on the mechanical seal assembly during operation.

Mechanical seal assemblies are known from the prior art in various configurations. In particular in the case of gas seals, very high axial forces may act on the components of the mechanical seal assembly in high-pressure applications with pressures of more than 200×105Pa. To absorb these high forces, it is known to use a so-called split ring, which is composed of several circumferential segments, to transmit the axial force to a shaft or the like. Deformations on this split ring may cause circumferential waviness, which in extreme cases can press-through to the slide surfaces of the slide rings due to elastic deformation. However, waviness on the slide surfaces must be avoided at all costs in order not to unnecessarily limit the performance of the mechanical seal. In the prior art, elastic secondary sealing elements are used between the split ring and the mechanical seal to reduce the waviness that may be transferred from the split ring to the slide surfaces. These can be elastically deformed when axial forces occur and thus reduce the risk of undesirable waviness being transferred to the slide surfaces of the mechanical seal. In high-pressure applications and also in sealing tasks where the medium to be sealed has high temperatures, elastic secondary sealing elements cannot be used or can only be used to a limited extent.

It is therefore the object of the present invention to provide a mechanical seal assembly which can prevent the transmission of waviness from a split ring to the slide surfaces of the mechanical seal assembly with a simple structure and simple, low-cost manufacturability and which is also suitable in particular for high-pressure applications and high-temperature applications.

This object is achieved by means of a mechanical seal assembly having the features of claim1. The dependent claims specify preferred embodiments of the invention.

In contrast, the mechanical seal assembly according to the invention having the features of claim1provides the advantage that axial forces acting on the mechanical seal assembly can be absorbed significantly better and transmitted to a rotating component. In particular, waviness can be prevented from being impressed on the slide surfaces of the mechanical seal assembly when axial forces occur. According to the invention, this is achieved in that the mechanical seal assembly comprises a mechanical seal for sealing between a high-pressure region and a low-pressure region on a shaft or the like, which comprises a rotating slide ring with a first slide surface and a stationary slide ring with a second slide surface, wherein a sealing gap is defined between the slide surfaces of the slide rings. Furthermore, a slide ring carrier is provided for the rotating slide ring, which is configured for a rotationally fixed connection with the rotating component, in particular a shaft. The slide ring carrier comprises a sleeve region. Furthermore, the mechanical seal assembly comprises a force support arrangement, which is configured to support an axial force acting on the mechanical seal assembly. The force support arrangement is arranged on an end face of the sleeve region of the slide ring carrier. The force support arrangement comprises a clamping sleeve, a conical sleeve and a split ring with at least two segments. The split ring is divided into several circumferential segments in the radial direction of the mechanical seal assembly, which are connected to each other on a rotating component in the assembled state. Furthermore, a conical connection is formed between the clamping sleeve and the conical sleeve. The clamping sleeve bears against the end face of the sleeve region of the slide ring carrier and the conical sleeve bears against a side surface of the split ring.

Thus, when an axial force acting on the mechanical seal assembly occurs, a force is transmitted from the slide ring carrier to the clamping sleeve, from the clamping sleeve to the conical sleeve, from the conical sleeve to the split ring, and from the split ring to the rotating component. The axial force is thus transmitted via four connection surfaces, namely a first connection surface between the sleeve region and the clamping sleeve, a second connection surface at the conical connection between the clamping sleeve and the conical sleeve, a third connection surface between the conical sleeve and the split ring and a fourth connection surface between the split ring and the rotating component.

A particular advantage of the configuration according to the invention is that by using the conical connection between the clamping sleeve and the conical sleeve, a component of the axial force in the radial direction can be transmitted directly to the rotating component via an inner circumference of the conical sleeve. This significantly reduces the axial force that ultimately remains on the fourth connection surface for transmission to the rotating component. This prevents the separation points of the split ring from being impressed onto the slide surfaces of the mechanical seal assembly.

In order to achieve the most compact configuration possible and to ensure reliable force transmission from the clamping sleeve to the conical sleeve, the clamping sleeve preferably comprises a receiving space to accommodate the conical sleeve. The conical sleeve can preferably be arranged in the receiving space of the clamping sleeve to a large extent, in particular by more than 80% of its extent in the axial direction.

Preferably, the receiving space of the clamping sleeve comprises a first inner-side conical surface and the conical sleeve comprises a second outer-side conical surface. The two conical surfaces form the conical connection between the clamping sleeve and the conical sleeve.

The conical connection is preferably arranged at an angle a of 35°±8°, in particular 35°±3°, to a central axis X-X of the mechanical seal. Depending on the selection of angle α<45°, a greater force of a radial force transmission via the conical sleeve into the rotating component can be achieved than axial force transmission in the direction of the split ring.

It is particularly preferable for the average diameter of the split ring to be larger than the inner diameter of the conical sleeve. This results in a favorable application of force from the conical sleeve to the split ring. In particular, inherent deformation of the split ring is reduced in this contact area of the split ring.

The clamping sleeve, the split ring, the slide ring carrier and the conical sleeve are particularly preferably made of metal material, in particular of the same metal material. Steel is preferably used as the metal material. This means that the mechanical seal assembly can be used in particular in high-temperature applications, in which the use of elastic sealing elements is not possible due to the destruction of elastic sealing elements caused by the high temperatures, as well as in high-pressure applications, in which there is a high probability that waviness will be imprinted onto the slide surfaces of the slide rings when split rings are used. When using different materials for the clamping sleeve, the split ring, the slide ring carrier and the conical sleeve, the different materials preferably have the same or very similar (±10%) coefficient of thermal expansion.

The split ring is particularly preferably arranged in a groove in the rotating component, in particular in a groove in a shaft.

An axial gap is also preferably provided on the inner circumferential region between the clamping sleeve and the conical sleeve. This provides the force support arrangement with at least certain damping properties when an axial force is introduced. The axial force can thus be reliably transmitted from the sleeve region of the slide ring carrier to the rotating component via the force transmission path.

In order to further improve the transmission of the axial force, a screw connection is preferably formed between the sleeve region of the slide ring carrier and the clamping sleeve. The screw connection preferably comprises a large number of screw bolts arranged along the circumference, which are guided through the clamping sleeve and screwed into the end face of the sleeve region.

The mechanical seal assembly is also preferably a gas seal for sealing a gaseous medium. The gaseous medium is particularly preferably under high pressure, preferably more than 200×105Pa, and high temperature, in particular more than 400° C.

A mechanical seal assembly1according to a preferred exemplary embodiment of the invention will be described in detail below with reference toFIGS.1to5.

As can be seen fromFIG.1, the mechanical seal assembly1comprises a mechanical seal2with a rotating slide ring3and a stationary slide ring4. The rotating slide ring3comprises a first slide surface30and the stationary slide ring4comprises a second slide surface40. A sealing gap5is defined between the two slide surfaces30,40of the slide rings3,4.

As can also be seen fromFIG.1, the mechanical seal assembly1seals a high-pressure region8from a low-pressure region9on a shaft7. In the high-pressure region8, a gas under high pressure, in particular more than 200×105Pa, is preferably present as the medium to be sealed.

The rotating slide ring3is connected to the shaft7by means of a slide ring carrier31in a co-rotational manner. The slide ring carrier31comprises a sleeve region32arranged on the shaft7and a holding region33, which partially encloses the rotating slide ring3. Thus, when the shaft7is rotating, force is transmitted from the shaft7to the slide ring carrier31and from this to the rotating seal ring3.

A metallic seal34without an elastic secondary seal is also preferably formed between the slide ring carrier31and the rotating slide ring3. This means that no elastic secondary sealing element has to be provided between the slide ring carrier31and the rotating slide ring3to seal the gap between these two components, so that both a high-pressure application and a high-temperature application are possible without any problems.

The mechanical seal assembly1further comprises a force support arrangement6. The force support arrangement6can be seen in detail inFIG.3. The force support arrangement6comprises a clamping sleeve60, a conical sleeve61and a split ring62.

The split ring62is a ring divided into two circumferential segments, wherein in this exemplary embodiment, the split ring62comprises a first segment621and a second segment622. The two segments are connected to each other via screw connections63(seeFIG.2). Alternatively, the split rings are held by means of a sleeve pushed over them.

The split ring62is arranged in a groove70in the shaft7.

The clamping sleeve60can be seen in detail inFIG.4. In particular, the clamping sleeve60comprises a first conical surface60aand a receiving space16. Just like the first conical surface60a,the receiving space16is formed on a radial inner side, i.e. a side of the clamping sleeve60facing the shaft7. The receiving space16serves to receive the conical sleeve61, as can be seen inFIGS.1and3.

The conical sleeve61can be seen in detail inFIG.5. The conical sleeve61comprises a second conical surface61a.Furthermore, the conical sleeve61comprises an inner circumference61b,with which the conical sleeve61is arranged on the shaft7.

The force support arrangement6is configured to support an axial force F acting on the mechanical seal assembly1. Such axial forces F can occur during operation of the mechanical seal assembly, in particular depending on a load on a machine to be sealed, and in particular in the event of load changes.

As can also be seen fromFIGS.1and3, a conical connection is formed between the clamping sleeve60and the conical sleeve61, which is provided by the first conical surface60aof the clamping sleeve60and the second conical surface61aof the conical sleeve61. The conical sleeve61is accommodated in the receiving space16of the clamping sleeve60.

As can also be seen fromFIGS.1and3, the clamping sleeve60bears against an end face32aof the sleeve region32of the slide ring carrier31in the assembled state. Furthermore, the conical sleeve61bears against a side surface62aof the split ring62.

Furthermore, the conical sleeve61has an inner diameter D1that is smaller than an average diameter D2of the split ring62(seeFIG.1). This ensures a force transmission into a radially inner region of the split ring62, whereby the transmission of the axial force from the split ring62to the shaft7is achieved without a large leverage effect.

The conical connection between the clamping sleeve60and the conical sleeve61has an angle α to a central axis X-X of the mechanical seal assembly1(seeFIG.1). The angle α is preferably in a range of 35°±3°.

The clamping sleeve60is connected to the sleeve region32of the slide ring carrier31by means of a bolt15. Preferably, several bolts15are arranged at the same distance from one another along the circumferential direction of the clamping sleeve.

The slide ring carrier31, the clamping sleeve60, the conical sleeve61and the split ring62are all made of a steel material, preferably the same steel material. This ensures that the mechanical seal assembly1can be used for high-pressure applications as well as for high-temperature applications.

As can also be seen fromFIG.3, four connection surfaces are thus provided between the slide ring carrier31and the shaft7for transmitting the axial force F. A first connection surface11is formed between the sleeve region32and the clamping sleeve60. A second connection surface12, which creates the conical connection, is formed between the clamping sleeve60and the conical sleeve61. A third connection surface13is formed between the conical sleeve61and a side surface62aof the split ring62. A fourth connection surface14is formed between the split ring62and the shaft7in the area of the groove70(seeFIG.3).

Thus, if an axial force Facts on the mechanical seal assembly1during operation of the mechanical seal assembly1, this force is transmitted via the slide ring carrier31to the force support arrangement6, which is arranged on the shaft7. By providing the conical second connection surface12between the clamping sleeve60and the conical sleeve61, the force F is thus divided into an axial component F1and a radial component F2. The radial component F2is then transmitted directly to the shaft7via the inner circumference61bof the conical sleeve61. This significantly reduces the force remaining to be transmitted from the conical sleeve61to the split ring62and from this to the shaft7via the groove70.

In this way, load-induced waviness in particular, which can occur due to deformation of the split ring62when the axial force F occurs, can be reduced to such an extent that this waviness is not imprinted on the slide surfaces30,40of the slide rings.

Furthermore, there is an axial gap10between the clamping sleeve60and the conical sleeve61(seeFIG.3). The axial gap10provides a certain damping effect when axial forces F occur, which enables a certain inherent deformation of the components of the force support arrangement6.

Since deformation of the steel used as material for the slide ring carrier31, the clamping sleeve60, the conical sleeve61and the split ring62is relatively low, an improved configuration of components of the mechanical seal assembly1can also be realized.

In particular, a maximum magnitude of the introduction of waviness caused by the split ring62onto the slide surfaces30,40can be achieved by selecting the angle a of the conical connection between the clamping sleeve60and the conical sleeve61.

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