BEARING ARRANGEMENT FOR A SHAFT IN A TURBOCOMPRESSOR

Abstract

The invention relates to a bearing arrangement for a shaft in a turbocompressor having at least one water-fed hydraulic bearing, which is configured to support for rotation an axle of the turbocompressor, wherein the water-fed hydraulic bearing encloses the shaft at a circumference of the shaft to form a bearing gap therebetween; and wherein the water-fed hydraulic bearing is configured to allow water to flow through the bearing gap to support the shaft hydraulically; and two seals, which are designed to seal the bearing gap against the shaft; and wherein gas from the turbocompressor is applied to the two seals outside the bearing gap to seal the bearing.

Claims

1. A bearing arrangement (200) for a shaft (118) in a turbocompressor, the bearing arrangement having: at least one water-fed hydraulic bearing (120), which is configured to rotatably support an a shaft (118) of the turbocompressor, wherein the water-fed hydraulic bearing (120) is configured to enclose the shaft (118) at a circumference of the shaft (118) in order to form a bearing gap (156) therebetween; and wherein the water-fed hydraulic bearing (120) is configured to allow water to flow through the bearing gap (156) in order to support the shaft (118) hydraulically; and two seals, which are configured to seal the bearing gap (156) with respect to the shaft (118), when gas from the turbocompressor is applied to the two seals outside the bearing gap (156) in order to seal the bearing (120).

2. The bearing arrangement (200) as claimed in claim 1, wherein each of the two seals comprises two sealing elements (152, 154), which define a cavity with the bearing (120) and the shaft (118); and wherein the bearing (120) has an opening between the two sealing elements (152, 154) in order to fluidically connect the cavity to a water tank (130).

3. The bearing arrangement (200) as claimed in claim 1 , wherein a gas seal is arranged outside of each of the two seals, with an interspace relative to the respective seal which is configured to seal the bearing gap (156) with respect to the shaft (118), and the water-fed hydraulic bearing (120) is configured to apply the gas from the turbocompressor to the respective seal outside the bearing gap (156) by means of the interspace.

4. The bearing arrangement (200) as claimed in claim 1 ,wherein the bearing gap (156) is configured to be fluidically connected to a water tank (130) in order to provide water for the bearing gap (156).

5. The bearing arrangement (200) as claimed in claim 4, wherein the water tank (130) has a pump (132) for pumping water from the water tank (130) into the bearing gap (156).

6. The bearing arrangement (200) as claimed in claim 1 , wherein the water-fed hydraulic bearing (120) is a hydrodynamic bearing and is configured to automatically draw in water for the bearing gap (156).

7. The bearing arrangement (200) as claimed in claim 1 , wherein the water flowing out of the bearing arrangement (200) is used to humidify air which is fed to a cathode of a fuel cell system by means of the turbocompressor.

8. The bearing arrangement (200) as claimed in claim 1 , wherein the water flowing out of the bearing arrangement (200) is used to cool components of a fuel cell system.

9. The bearing arrangement (200) as claimed in claim 1 , wherein the water for the hydrodynamic bearing comprises condensed water of a fuel cell system.

10. (canceled)

11. (canceled)

12. (canceled)

13. A turbocompressor comprising a shaft (118) having a circumference, an electric machine, a liquid cooling circuit (122), and a bearing arrangement (200) having at least one water-fed hydraulic bearing (120), which rotatably supports the shaft (118) of the turbocompressor, wherein the water-fed hydraulic bearing (120) encloses the shaft (118) at the circumference of the shaft (118) in order to form a bearing gap (156) therebetween; and wherein the water-fed hydraulic bearing (120) is configured to allow water to flow through the bearing gap (156) in order to support the shaft (118) hydraulically, and two seals, which seal the bearing gap (156) with respect to the shaft (118), wherein gas from the turbocompressor is applied to the two seals outside the bearing gap (156) in order to seal the bearing (120), and wherein the water flowing to and/or from the bearing gap (156) is passed through the liquid cooling circuit (122) in order to dissipate heat from the electric machine of the turbocompressor.

14. The turbocompressor as claimed in claim 13, wherein each of the two seals comprises two sealing elements (152, 154), which define a cavity with the bearing (120) and the shaft (118); and wherein the bearing (120) has an opening between the two sealing elements (152, 154) in order to fluidically connect the cavity to a water tank (130).

15. The turbocompressor as claimed in claim 13, wherein a gas seal is arranged outside of each of the two seals, with an interspace relative to the respective seal which is configured to seal the bearing gap (156) with respect to the shaft (118), and the water-fed hydraulic bearing (120) is configured to apply the gas from the turbocompressor to the respective seal outside the bearing gap (156) by means of the interspace.

16. The turbocompressor as claimed in claim 13, wherein the bearing gap (156) is configured to be fluidically connected to a water tank (130) in order to provide water for the bearing gap (156).

17. The turbocompressor as claimed in claim 16, wherein the water tank (130) has a pump (132) for pumping water from the water tank (130) into the bearing gap (156).

18. The turbocompressor as claimed in claim 13 wherein the water-fed hydraulic bearing (120) is a hydrodynamic bearing and is configured to automatically draw in water for the bearing gap (156).

19. The turbocompressor as claimed in claim 13, wherein the water flowing out of the bearing arrangement (200) is used to humidify air which is fed to a cathode of a fuel cell system by means of the turbocompressor.

20. The turbocompressor as claimed in claim 13, wherein the water flowing out of the bearing arrangement (200) is used to cool components of a fuel cell system.

21. The turbocompressor as claimed in claim 13, wherein the water for the hydrodynamic bearing comprises condensed water of a fuel cell system.

22. A cathode circuit of a fuel cell stack having a turbocompressor as claimed in claim 13, and a humidifier for humidifying the cathode air, wherein the cathode circuit is configured to feed the water flowing out of the bearing arrangement (200) to the humidifier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Exemplary embodiments of the invention are explained in greater detail below with reference to FIGS. 1 and 2. Here,

[0041] FIG. 1 shows a turbocompressor; and

[0042] FIG. 2 shows a bearing arrangement for a turbocompressor.

DETAILED DESCRIPTION

[0043] FIG. 1 shows a system 100 having a turbocompressor with water-fed hydraulic bearings 120, a cathode side of a fuel cell stack 140 and a water tank 130. The turbocompressor has a liquid cooling circuit 122, to which the water flowing to and/or from the bearing gap can be fed in order to dissipate heat from the electric machine of the turbocompressor.

[0044] At its inlet connection, the cathode side of the fuel cell stack 140 is supplied with air 142 via the compressor stage 112 of the turbocompressor, and, at the outlet connection of the cathode side of the fuel cell stack 140, energy can be recovered from the air mass flow 144 by means of a turbine 114 of the turbocompressor, since both turbomachines are arranged on a common shaft 118.

[0045] The common shaft 118 of the turbocompressor is supported with two water-fed hydraulic bearings 120. An electric drive motor 110 is arranged between the bearings, the components of the drive motor generating heat during operation, which must be dissipated.

[0046] The water from the water tank 130 can be fed to the water-fed hydraulic bearings 120 via fluid-carrying connecting lines 134 by means of a pump 132. In the case of a hydrostatic water-fed hydraulic bearing 120, pressure is built up in the bearing gap of the bearing, which encloses the shaft at a circumference, by means of this pump 132, ensuring that the shaft 118 of the turbocompressor is rotatably supported.

[0047] The water flowing into the bearing 120 flows through the bearing and through the liquid cooling circuit 122, which the turbocompressor has for cooling, and can then be used to feed in the air fed to the cathode side 140 of the fuel cell stack, by means of a feed 124. In this case, this feed 124 can provide the water to a humidifier, which is arranged in the feed of air for the cathode side 41 of the fuel cell stack. Channels of the liquid cooling circuit of the turbocompressor may also be arranged on the pressure side of the bearing arrangement. The water used for the water-fed hydraulic bearings, which can be taken from the water tank 130, can comprise condensed water from the air mass flow 144 of the outlet connection of the cathode side of the fuel cell stack 140. For this purpose, a condenser can be arranged in this air mass flow 144 and this condensed water can be passed into the water tank 130 via a fluid-carrying line 136.

[0048] FIG. 2 sketches details of the bearing arrangement 120 in a system 200 which, in addition to the bearing arrangement 120, has the shaft 118 of the turbocompressor and the water tank 130.

[0049] In this case, the water from the water tank 130 is passed into the bearing gap 156 by means of a fluid-carrying connecting line 134 in order to build up there the pressure necessary to support the shaft 118 of the turbocompressor, either by means of the rotating shaft 118, in the case of a hydrodynamic bearing, or by means of a pump 132, which is arranged in the connecting line 134. As described above, this water which is passed through the bearing gap 156 can be fed either to the cathode air flow 142 and/or to the liquid cooling circuit 122 of the turbocompressor via the connection line 122, which are connected to openings of the bearing in the region of the bearing gap 156.

[0050] The bearing gap 156 is sealed by means of two seals, each of which has two sealing elements 152, 154. In this case, gas from the turbocompressor is applied to the respective sealing element 154 which is located further out in order to seal the bearing.

[0051] Between the two sealing elements 152, 154, which are spaced apart from one another in order to form a cavity with the shaft 118, an opening is provided which, by means of a fluid-carrying connection 158, conducts any water entering this cavity into the water tank 130. Since gas from the turbocompressor is applied to the outer sealing element 154 of the respective seal, water which passes through the sealing element 152 located further inward is passed through the opening of the cavity between the two sealing elements 152, 154 into the water tank 130. This leads to particularly good sealing of the bearing arrangement, which is particularly important in ensuring that the water of the water-fed hydraulic bearing does not get into the turbine so as to avoid droplet impingement.