Rotary Joint with a Mechanical Seal

Abstract

A rotary joint including a stator and a rotor, each having at least one fluid channel, and a fluid transfer interface between the stator and the rotor, via which a fluid flows from the fluid channel in the stator into the fluid channel in the rotor, the fluid transfer interface being sealed off with respect to the surrounding environment by a mechanical seal, which comprises an abrasive sliding ring, and the sliding ring bears in an axial direction in an elastically biased manner against at least one mating ring and forms a seal face therewith. An axial displacement detection device is provided, which is designed to detect, in the event of wear on the sliding ring, an associated axial displacement of the stator and/or rotor. The axial displacement detection device comprises a rotary encoder on the rotor and a sensor that detects a position of the rotary encoder.

Claims

1.-10. (canceled)

11. A rotary joint comprising: a stator and a rotor, each having at least one fluid channel; a fluid transfer interface between the stator and the rotor, via which a fluid flows from the fluid channel in the stator into the fluid channel in the rotor, or vice versa, wherein the fluid transfer interface is sealed off with respect to the surrounding environment by means of a mechanical seal, which comprises an abrasive sliding ring, and the sliding ring bears in an axial direction in an elastically biased manner against at least one mating ring and forms a seal face therewith; wherein an axial displacement detection device is provided, which is designed to detect, in the event of wear on the sliding ring, an associated axial displacement of the stator and/or rotor; wherein the axial displacement detection device comprises a rotary encoder on the rotor and a sensor that detects a position of the rotary encoder, said sensor being located radially opposite the rotary encoder, and the rotary encoder comprises at least one discrete marker or a plurality of discrete markers arranged at intervals one after the other in the circumferential direction, said markers being arranged on the rotor, and the at least one discrete marker varies along the axial direction in its extent in the circumferential direction, and/or different numbers of individual discrete markers are provided, one after the other in the circumferential direction, in different axial sections of the rotor.

12. The rotary joint according to claim 11, wherein the position of the sensor and/or of the at least one rotary encoder is adjustable in the radial direction and/or axial direction.

13. The rotary joint according to claim 12, wherein the rotary encoder extends only over part of the circumference, in particular less than 45? or less than 10?.

14. The rotary joint according to claim 11, wherein the rotary encoder extends only over part of the circumference, in particular less than 45? or less than 10?.

15. The rotary joint according to claim 11, wherein the stator comprises a housing having at least one fluid inlet and/or fluid outlet, and the sensor is borne by a support element connected to the housing.

16. The rotary joint according to claim 15, wherein the support element comprises a sheet-metal strip that bears the sensor.

17. The rotary joint according to claim 11, wherein the rotary encoder (9) is formed by an angled plate connected to the rotor.

18. The rotary joint according to claim 11, wherein a control device is provided, which processes signals that are generated by the sensor as a function of the current circumferential position of the at least one marker, wherein the control device and/or the sensor generates a sequence of on/off signals.

19. The rotary joint according to claim 11, wherein a radial gap between the rotary encoder and the sensor is at least 1 or 2 mm, in particular at least 5 mm.

20. The rotary joint according to claim 11, wherein the sliding ring forms, on each of its two opposite end faces, a seal face with a respective mating ring and is rotatable in the circumferential direction relative to both mating rings.

21. The rotary joint according to claim 11, wherein the at least one discrete marker has a triangular shape.

Description

[0030] In the Figures:

[0031] FIG. 1 shows, in an axial cross-section, an exemplary embodiment of a rotary joint designed according to the invention;

[0032] FIG. 2 shows, in a side view, the rotary joint from FIG. 1 with a rotating component connected to the rotor;

[0033] FIG. 3 shows an isometric view of the rotary joint from FIG. 1;

[0034] FIG. 4 shows an alternative design of a possible rotary encoder.

[0035] FIG. 1 shows, in an axial cross-section, a rotary joint comprising a stator 1 and a rotor 2. Provided in the stator 1 are a first fluid channel 3.1 and a second fluid channel 3.2, of which, for example, one forms a forward flow and the other forms a return flow. Correspondingly, a first fluid channel 4.1 and a second fluid channel 4.2 are also provided in the rotor 2, with the sealing of said channels with respect to each other being visible only in FIG. 2 since an inner pipe section has not yet been inserted into the rotor 2 in the illustration in FIG. 1. The pipe section is merely indicated by the dashed line.

[0036] A fluid transfer interface 5 is provided between the stator 1 and the rotor 2, via which fluid can flow from the first fluid channel 3.1 in the stator 1 into the first fluid channel 4.1 in the rotor 2, or vice versa, and fluid can flow from the second fluid channel 3.2 in the stator 1 into the second fluid channel 4.2 in the rotor 2, or vice versa.

[0037] The fluid transfer interface 5 is sealed off by a mechanical seal 6, comprising a sliding ring 7 which, in the axial direction X corresponding to the axis of rotation of the rotor 2, bears in an elastically biased manner against at least one mating ring 8, here against two mating rings 8, and forms a seal face therewith. The sliding ring 7 thus advantageously has two axial end faces 7.1, 7.2 at opposite axial ends, each of which bears sealingly against a respective mating ring 8. In the event of relative rotation between the sliding ring 7 and one or both mating rings 8, wear occurs on these end faces 7.1, 7.2. In order to enable the sliding ring 7 to still bear sealingly against the mating rings 8, the rotor 2 and/or the stator 1 is adjusted in its axial position to compensate for the wear. As a result of this adjustment, which can be achieved by elastic biasing (see the elastic biasing force F shown in FIG. 1), the rotor 2 is displaced relative to the stator and/or the stator 1 is displaced relative to the rotor 2 due to an axial movement of the rotor 2 and/or the stator 1.

[0038] In the exemplary embodiment shown, one mating ring 8 is arranged in the stator 1 in particular in a rotationally fixed manner, and the other mating ring 8 rotates with the rotor 2.

[0039] In order to detect the relative movement in the axial direction X between the stator 1 and the rotor 2 and at the same time to detect the rotational speed of the rotor 2, a rotary encoder 9 and a sensor 10 are provided, which are located opposite each other in the radial direction. The sensor 10 is connected to the stator 1 in a positionally fixed manner, in this case to a housing 12 of the stator 1 which forms a fluid inlet 13 into the first fluid channel 3.1 and a fluid outlet 14 from the second fluid channel 3.2.

[0040] The sensor 10 is held in its predefined position radially outside the rotary encoder 9 by way of a support element 15 connected to the housing 12, said support element comprising a sheet-metal strip 16; the rotary encoder is formed by an angled plate 17, which is connected to the rotor 2 and bears or forms, for example, a single discrete marker 11. One preferred exemplary embodiment of the discrete marker 11 can be seen in FIGS. 2 and 3. Here, the discrete marker 11 has the shape of a triangle, the base side of which extends in the circumferential direction of the rotor, and the height of which extends in the axial direction X. Preferably, the discrete marker 11 is simply formed by an angled end of the angled plate 17. This enables particularly cost-effective manufacture. The rotary encoder 9 thus comprises just one single marker 11 over the circumference and extends in the circumferential direction only within the angle range of this marker 11.