mechanical seal arrangement

Abstract

Mechanical seal arrangement comprising: a mechanical seal (2) with a first sliding ring (3) and a second sliding ring (4), wherein a sealing gap (5) is defined between a sliding surface of the first sliding ring (3) and a sliding surface of the second sliding ring (4), a torque transmission unit (6) for transmitting a torque to the second sliding ring (4) comprising a first transmission component (66) with a head (60) and a base body (61), a preloading device (7) for axially preloading the second sliding ring (4), which exerts an axial preload on the second sliding ring (4) at a rear side (4a) of the second sliding ring (4), a first recess (40) at the rear side (4a) of the second sliding ring (4) in which the head (60) of the transmission component is arranged with clearance, wherein the base body (61) is arranged with clearance in a second recess (52) in a housing (10), and a pressure ring (8) with a through opening (80),through which the base body (61) is loosely passed, wherein the preloading device (7) engages the pressure ring (8), and the pressure ring (8) secures the head (60) in the first recess (40) in the second sliding ring (4), and wherein the preloading device (7) and the torque transmission unit (6) are arranged parallel to each other in the circumferential direction.

Description

[0001] The present invention relates to a mechanical seal arrangement with a torque transmission unit which enables a compact design in the axial direction.

[0002] Mechanical seal assemblies are known in various configurations from the prior art. For example, cylindrical pins are used to transmit and / or support torque at the sliding rings. Such cylindrical pins can be pressed into a sliding ring and / or another component using an interference fit. However, this can create stresses, particularly in the sliding ring, which can lead to microcracks during operation and, in extreme cases, to complete failure of the sliding ring and thus to undesirable leakage. DE 20 2022 103 990 U1 discloses a simple cartridge-shaped mechanical seal assembly with additional sealing provided by a stuffing box. Furthermore, DD 2 44 394 A1 discloses a mechanical shaft seal with a carbon ring and a wear indicator for agitators.

[0003] It is therefore an object of the present invention to provide a mechanical seal arrangement which, with a simple design and simple, cost-effective manufacturability, enables improved torque transmission in an axially small design.

[0004] This problem is solved by a mechanical seal arrangement having the features of claim 1. The dependent claims describe preferred embodiments of the invention.

[0005] The mechanical seal assembly according to the invention, with the features of claim 1, has the advantage that a very small size in the axial direction can be achieved. Furthermore, the mechanical seal assembly according to the invention is very easy to assemble and can be manufactured and assembled particularly cost-effectively. This is achieved according to the invention by the mechanical seal assembly comprising a mechanical seal with a first, in particular rotating, sliding ring and a second, in particular stationary, sliding ring. The first sliding ring has a first sliding surface and the second sliding ring has a second sliding surface, wherein a sealing gap is defined between the two sliding surfaces. The mechanical seal assembly further comprises a torque transmission unit on the second sliding ring. The torque transmission unit comprises a transmission component with a head and a base body.The transmission component is preferably a bolt with a cylindrical head and a cylindrical base body without threads. The mechanical seal assembly further comprises a preloading device for axially preloading the second sliding ring. The preloading device is arranged on the rear side of the second sliding ring and exerts an axial preload on the second sliding ring. The second sliding ring also has a first recess on its rear side in which the head of the transmission component is arranged with clearance. The base body of the transmission component is arranged with clearance in a second recess in the assembly. Thus, both the head and the base body are arranged with clearance in the axial and radial directions within their respective recesses. The mechanical seal assembly further comprises a pressure ring with a through-hole. The base body of the transmission component is loosely guided through the through-hole in the pressure ring.The preloading device engages the pressure ring and exerts axial pressure to preload the second sliding ring axially. The pressure ring thus secures the head of the torque transmission unit within the second sliding ring. Furthermore, the preloading device and the torque transmission unit are arranged parallel to each other in the circumferential direction. This parallel arrangement of the preloading device and the torque transmission unit enables a particularly short axial design of the mechanical seal assembly. Preferably, transmission components and the preloading device, in particular helical springs, are arranged alternately in the circumferential direction. It is also possible for several helical springs to be arranged circumferentially between two adjacent transmission components. The through-hole has a diameter such that the base body is also arranged with clearance within the through-hole.This allows for a simple and cost-effective compensation of any manufacturing-related tolerance deviations in the components of the mechanical seal assembly. Furthermore, the all-around clearance greatly simplifies the assembly of the torque transmission unit, making it virtually error-free.

[0006] The mechanical seal assembly is further configured as a tandem mechanical seal assembly and comprises a first and a second mechanical seal. The first and second mechanical seals are arranged in series, with the second, and in particular the stationary, sliding rings of the first and second mechanical seals positioned back-to-back. The torque transmission unit and the preload device are arranged axially between the two mechanical seals, more precisely between the two second sliding rings. The torque transmission unit comprises a first transmission component on the second sliding ring of the first mechanical seal and a second transmission component on the second sliding ring of the second mechanical seal.Furthermore, the torque transmission unit comprises a first pressure ring on the rear side of the second sliding ring of the first mechanical seal and a second pressure ring on the rear side of the second sliding ring of the second mechanical seal. The two pressure rings are preferably identical in design. Furthermore, the first and second transmission components and the preloading device are arranged parallel to each other in the circumferential direction. This allows for a tandem mechanical seal assembly with a particularly short axial design.

[0007] A particularly cost-effective design is possible if the preload device has a large number of springs, especially coil springs, which are arranged parallel to each other along the circumference.

[0008] Preferably, the preloading device is arranged with clearance in a third recess in a housing, particularly a stationary one. This also allows any tolerance deviations that may exist to be compensated for by the preloading device.

[0009] Preferably, the pressure ring has exactly two through-openings which are arranged opposite each other by 180°.

[0010] Preferably, the torque transmission unit comprises exactly two first transmission components and exactly two second transmission components. This significantly increases the number of identical parts.

[0011] The component on which the second sliding rings of the first and second mechanical seals are arranged is preferably a sleeve-shaped housing. The sleeve-shaped housing thus acts as a sliding ring carrier for both second sliding rings.

[0012] The mechanical seal assembly is preferably designed as a pre-assembled unit. This makes installation at the customer's site particularly easy and quick.

[0013] Preferably, the preloading device is configured such that it preloads both the pressure ring of the first mechanical seal and the pressure ring of the second mechanical seal.

[0014] In particular, the number of identical parts can be further increased when using two pressure rings. When two pressure rings are used, they are preferably arranged circumferentially offset from each other by 90°.

[0015] The preloading device preferably comprises a plurality of cylindrical springs, all of which are identical in design.

[0016] The cylindrical springs preferably have a diameter equal to the width of the pressure ring. This ensures optimal contact between the cylindrical springs and the pressure ring.

[0017] The first recess for receiving the head of the torque transmission unit is preferably a radial slot on the back of the second sliding ring. This can be manufactured simply and cost-effectively, and in particular, no undesirable stresses are introduced into the second sliding ring by means of a bore for receiving the head.

[0018] Preferably, the first sliding ring is the rotating sliding ring and the second sliding ring is the stationary sliding ring. Alternatively, the first sliding ring is the stationary sliding ring and the second sliding ring is the rotating sliding ring. This means that the inventive concept for preload and torque transmission can be implemented either on the rotating or the stationary sliding rings.

[0019] The invention further relates to a conveying device, in particular a screw pump or a screw compressor.

[0020] Several embodiments of the invention are 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 example, Fig. 2 a top view of a pressure ring of the mechanical seal assembly of Fig. 1, Fig. 3 a schematic sectional view of a mechanical seal arrangement according to a first embodiment of the invention, Fig. 4 A schematic, perspective view of a torque transmission unit and a preload device of the mechanical seal assembly of Fig. 3 Fig. 5 a schematic sectional view of the mechanical seal arrangement of Fig. 3 along other cutting lines and Fig. 6 a schematic sectional view of a mechanical seal arrangement according to a second embodiment of the invention.

[0021] The following refers to the Fig. 1 and Fig. 2 a mechanical seal arrangement 1 according to a first example of the invention is described in detail.

[0022] As from Fig. As can be seen in Figure 1, the mechanical seal arrangement 1 comprises a mechanical seal 2 with a rotating sliding ring 3 and a stationary sliding ring 4. A sealing gap 5 is defined between a sliding surface of the rotating sliding ring 3 and a sliding surface of the stationary sliding ring 4.

[0023] The mechanical seal arrangement 1 seals a first area 11 with a medium to be sealed from a second area 12, e.g. an atmospheric area.

[0024] The rotating sliding ring 3 is connected to a rotating shaft 9 via a sliding ring carrier 30 and a sleeve 31.

[0025] A first secondary seal 33 is arranged on an inner circumference of the rotating sliding ring 3. A second secondary seal 42 is arranged on an outer circumference of the stationary sliding ring 4. The sliding ring carrier 30 is rotationally fixed to the sleeve 31, which is fixed to the shaft 9, via a screw bolt 32. This allows torque to be transmitted to the rotating sliding ring 3 via the sleeve 31 and the sliding ring carrier 30 when the shaft 9 rotates.

[0026] To prevent the second sliding ring 4 from rotating with the rotating sliding ring 3, particularly when the mechanical seal assembly 1 is started up, a torque transmission unit 6 is necessary. The torque transmission unit 6 prevents the stationary sliding ring 4 from rotating and, in this embodiment, comprises a transmission component 66 in the form of a bolt with a head 60 and a cylindrical base body 61.

[0027] This is as described in Fig. As shown in the upper part of the sectional view, a first recess 40 is formed on a rear side 4a of the stationary sliding ring 4. In this embodiment, the first recess 40 is a radial slot.

[0028] The mechanical seal assembly 1 further comprises a preloading device 7. The preloading device 7 of this embodiment comprises a plurality of helical springs 70. The preloading device 7 preloads the stationary sliding ring 4 in axial direction XX against the rotating sliding ring 3.

[0029] As from Fig. As can be seen in Figure 1, a second recess 52 is formed in a stationary housing 10. The second recess 52 serves to receive the base body 61 of the torque transmission unit 6. As shown in detail in Figure 1, a second recess 52 is formed in a stationary housing 10. The second recess 52 serves to receive the base body 61 of the torque transmission unit 6. Fig. As can be seen in Figure 1, the head 60 of the torque transmission unit 6 is arranged in the first recess 40. The head 60 has play in both the radial and axial directions. Thus, the head 60 is arranged with play in the first recess 40.

[0030] The base body 61 is also arranged with radial and axial play in the second recess 52.

[0031] The housing 10 also includes a third recess 53 in which the coil spring 70 of the preload device 7 is arranged. The coil spring 70 is also arranged with radial play in the third recess 53. The third recess 53 is preferably a blind hole to provide a support for the coil spring 70 at a first end.

[0032] The preloading device 7 exerts an axial preload force F in the axial direction XX, which is transmitted via a pressure ring 8 located in Fig. As shown in Figure 2, the force is transferred to the stationary sliding ring 4. The pressure ring 8 has two through-openings 80, each designed to receive a transmission component 66 of the torque transmission unit 6. A clearance exists between the base body 61 and the through-opening 80. As shown in Figure 2, the force is transferred to the stationary sliding ring 4. The pressure ring 8 has two through-openings 80, each designed to receive a transmission component 66 of the torque transmission unit 6. A clearance is present between the base body 61 and the through-opening 80. Fig. As can be seen in Figure 1, the head 60 of the transmission component 66 is thus held in the first recess 40 by the pressure ring 8.

[0033] The pressure ring 8 distributes the preload force F evenly onto the stationary sliding ring 4.

[0034] This arrangement of the transmission component 66 of the torque transmission unit 6 with clearance allows manufacturing-related dimensional deviations to be compensated for.

[0035] As from the Fig. 1 and Fig. As can be seen in Figure 2, two transmission components 66 with head 60 and base body 61 of the torque transmission unit 6 are provided, which are arranged opposite each other by 180°. Several helical springs 70, preferably two each, are arranged circumferentially between the transmission components 66 of the torque transmission unit 6.

[0036] Thus, the transmission components 66 of the torque transmission unit 6 and the coil springs 70 of the preload device 7 are arranged parallel to each other in the circumferential direction. This means that the transmission components 66 and the coil springs 70 are arranged at the same axial height, allowing for a very short axial length XX of the mechanical seal assembly 1. The transmission components 66 are arranged with clearance in all recesses, eliminating the need to drive the bolts into the respective recesses. This prevents, in particular, stresses and / or cracks from being introduced into the stationary sliding ring 4 by an interference fit between a bolt and the stationary sliding ring.

[0037] Since only the head 60 of the transmission component 66 needs to be accommodated in the stationary sliding ring 4, the first recess 40 does not need to have a large axial depth. This has advantages with regard to the axial length of the rotating sliding ring 3, which can be significantly shorter than in the prior art.

[0038] The Fig. 3, Fig. 4 to Fig. Figure 5 shows a mechanical seal arrangement 1 according to a first embodiment of the invention. Identical or functionally equivalent parts are designated with the same reference numerals as in the first embodiment.

[0039] As from the Fig. 3 and Fig. As can be seen in Figure 5, the mechanical seal arrangement 1 of the first embodiment is a tandem arrangement. The mechanical seal arrangement 1 comprises a first mechanical seal 2 and a second mechanical seal 102. The two mechanical seals 2, 102 are each arranged in series with their stationary sliding rings 4, 104 lying relative to each other.

[0040] This allows for a so-called back-to-back arrangement.

[0041] The first mechanical seal 2 corresponds essentially to the mechanical seal of the first example, and the second mechanical seal 102 has, in addition to the stationary sliding ring 104, a rotating sliding ring 103, wherein a sealing gap 105 is defined between the rotating sliding ring 103 and the stationary sliding ring 104. The rotating sliding ring 103 is connected to the sleeve 31 via a sliding ring carrier 130 and a screw bolt 32 in a rotationally fixed manner.

[0042] In the first embodiment of the invention, the sleeve 31 and the sliding ring carrier for the rotating sliding ring 3 of the first mechanical seal 2 are a one-piece component.

[0043] The mechanical seal assembly 1 of this first embodiment is designed as a pre-assembled unit.

[0044] In this case, the mechanical seal 1 has a sleeve-shaped stationary housing 10, which serves as a sliding ring carrier for the two second sliding rings 4, 104.

[0045] What's next from the Fig. 3 and Fig. As can be seen in Figure 5, a preload device 7 and a torque transmission unit 6 with first transmission components 66 for the stationary sliding ring 4 and second transmission components 106 for the stationary sliding ring 104 are provided in the axial direction XX between the stationary sliding ring 4 of the first mechanical seal 2 and the stationary sliding ring 104 of the second mechanical seal 102.

[0046] In detail, the first transmission components are 66, the second transmission components are 106 and the pre-tensioning device is 7. Fig. 4. To prevent the stationary sliding rings 4, 104 from rotating, the torque transmission unit 6, as described in the first embodiment, is provided on the stationary sliding ring 4. Second transmission components 106 are provided on the stationary sliding ring 104, which are designed identically to the first transmission components 66, except that the second transmission components 106 are arranged in a mirrored configuration. This is shown in detail in Figure 4. Fig. 5 is visible.

[0047] The first torque transmission unit 6 thus prevents the stationary sliding ring 4 and the stationary sliding ring 104 from rotating together by means of identically constructed transmission components 66, 106.

[0048] Both stationary sliding rings 4, 104 are connected by a common preloading device 7 with a plurality of coil springs 70 (cf. Fig. 4) axially preloaded XX. The helical springs 70 and the transmission components 66, 106 are arranged parallel to each other in the circumferential direction. A first pressure ring 8 is provided for the stationary sliding ring 4 and a second pressure ring 108 for the stationary sliding ring 104 of the second mechanical seal. The two pressure rings 8, 108 are identical, namely as a ring with two through-openings 80, but are arranged offset from each other by 90° in the circumferential direction. This allows both the first transmission component 66 and the second transmission component 106 to be arranged parallel to the helical springs 70 in the circumferential direction.

[0049] The mechanical seal arrangement 1 of the first embodiment has only one preload device 7, which, as shown in Fig. 3, indicated by the double arrow F, exerts a preload force on the stationary sliding rings 4, 104 in both axial directions.

[0050] Thus, a particularly compact and, in particular, axially short tandem mechanical seal assembly 1 can be realized. Since the first and second torque transmission units 6, 106 are identically constructed with the same parts, the mechanical seal assembly 1 can have a large number of identical parts.

[0051] Fig. Figure 6 shows a mechanical seal arrangement according to a second embodiment of the invention. The second embodiment corresponds essentially to the first embodiment, except that in the second embodiment the preload device and the torque transmission unit are arranged on the rotating sliding ring and not on the stationary sliding ring as in the first embodiment.

[0052] How in detail from Fig.As can be seen in Figure 6, a first recess 40 is formed in a rear side 3a of the rotating sliding ring 3. This recess is designed as a radial slot and serves to receive the head 60 of the transmission component 66. The base body 61 of the transmission component 66 is arranged in a second recess 52 in a sliding ring carrier 30. The sliding ring carrier 30 is connected via a screw bolt 32 to a sleeve 31, which rotates together with the shaft 9. Thus, torque is transmitted from the shaft 9 via the sleeve 31 and the sliding ring carrier 30 to the transmission component 66 and from the head 60 of the transmission component 66 to the rotating sliding ring 3.

[0053] As illustrated by the second embodiment, the present invention can be used both for transmitting torque from a rotating component to a rotating sliding ring and for supporting torque on a stationary sliding ring.

[0054] Otherwise, the second embodiment corresponds to the first embodiment, so reference can be made to the description given there. Reference symbol list 1 Mechanical seal assembly 2 mechanical seals 3 rotating sliding ring 3a Back side of the rotating sliding ring 4 stationary sliding ring 4a Back side of the second sliding ring 5 Sealing gap 6 Torque transmission unit 7 Pre-tensioning device 8 pressure ring 9th wave 10 cases 11 first area 12 second area 30 sliding ring carriers 31 Sleeve 32 screw bolts 33 first secondary seal 40 first exception 42 second secondary seal 52 second exception 53 third exception 60 heads 61 Basic bodies 66 first transmission component 70 coil spring 80 Through opening 102 second mechanical seal 103 rotating sliding ring 104 stationary sliding ring 105 Sealing gap 106 second transmission component 108 second pressure ring 130 sliding ring carriers F Preload force XX Axial direction

Claims

[1] Mechanical seal assembly comprising: - a mechanical seal (2) with a first sliding ring (3) and a second sliding ring (4), wherein a sealing gap (5) is defined between a sliding surface of the first sliding ring (3) and a sliding surface of the second sliding ring (4), - a torque transmission unit (6) for transmitting a torque to the second sliding ring (4) comprising a first transmission component (66) with a head (60) and a base body (61), - a preloading device (7) for axially preloading the second sliding ring (4), which exerts an axial preload on the second sliding ring (4) at a rear side (4a) of the second sliding ring (4), - a first recess (40) on the rear side (4a) of the second sliding ring (4) in which the head (60) of the transmission component is arranged with clearance, wherein the base body (61) is arranged with clearance in a second recess (52) in a housing (10), and - a pressure ring (8) with a through-opening (80) through which the base body (61) is loosely passed, wherein the preloading device (7) engages the pressure ring (8), and the pressure ring (8) secures the head (60) in the first recess (40) in the second sliding ring (4), - wherein the preloading device (7) and the torque transmission unit (6) are arranged parallel to each other in the circumferential direction, and - further comprising a second mechanical seal (102) which is arranged in series with the first mechanical seal (2), wherein the second sliding rings (4, 104) of the first and second mechanical seals (2, 102) are arranged back to back, - wherein the torque transmission unit (6) is arranged in the axial direction XX between the first mechanical seal (2) and the second mechanical seal (102), - wherein the torque transmission unit (6) comprises a first transmission component (66) on the second sliding ring of the first mechanical seal (2) and a second transmission component (106) on the second sliding ring (104) of the second mechanical seal (102), a first pressure ring (8), a second pressure ring (108) and a preloading device (7), - wherein the preloading device (7) is arranged in the axial direction XX between the first pressure ring (8) and the second pressure ring (108), and - wherein the first transmission component (66), the second transmission component (106) and the pretensioning device (7) are arranged parallel to each other in the circumferential direction. [2] Sliding ring seal arrangement according to claim 1, wherein the preload device (7) has a plurality of springs arranged along the circumference. [3] Sliding ring seal arrangement according to one of the preceding claims, wherein the preload device (7) is arranged with clearance in a third recess (53) in the housing (10). [4] Mechanical seal arrangement according to one of the preceding claims, wherein the pressure ring (8) has exactly two through-openings (80) which are arranged opposite each other by 180°. [5] Mechanical seal arrangement according to claim 1, wherein the torque transmission unit (6) has exactly two first transmission components (66) and exactly two second transmission components (106). [6] Mechanical seal arrangement according to claim 1 or 5, wherein the housing (10) is sleeve-shaped. [7] Mechanical seal arrangement according to one of the preceding claims, wherein the mechanical seal arrangement is a pre-assembled assembly. [8] Mechanical seal arrangement according to one of claims 1 or 5 to 7, wherein the preloading device (7) preloads the second sliding ring (4) of the first mechanical seal (2) and the second sliding ring (104) of the second mechanical seal (102). [9] Sliding ring seal arrangement according to one of the preceding claims, wherein the preload device (7) comprises a plurality of cylindrical springs. [10] Mechanical seal arrangement according to one of the preceding claims, wherein the first recess (40) in the second sliding ring (4) is a radial slot. [11] Mechanical seal arrangement according to one of the preceding claims, - wherein the first sliding ring (3, 103) is a rotating sliding ring and the second sliding ring (4, 104) is a stationary sliding ring or - wherein the first sliding ring is a stationary sliding ring (4, 104) and the second sliding ring (3, 103) is a rotating sliding ring.

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