Cooling system

Patent metadata

Field	Value
Publication number	US-10337773-B2
Application number	US-201615347376-A
Country	US
Kind code	B2
Filing date	Nov 9, 2016
Priority date	Nov 9, 2016
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A cooling system includes a refrigerant compressor and a first operating medium, which provides a mixture of refrigerant and lubrication oil. An oil separator reduces the percentage of the refrigerant in the operating medium to a value between 15% by weight and 50% by weight.

First claim

The invention claimed is:

1. A cooling system comprising:
a refrigerant compressor, and
an oil separator configured to separate a combined operating medium comprising a mixture of a refrigerant and a lubrication oil into a first operating medium and a second operating medium, wherein the second operating medium comprises between 15% by weight and 50% by weight of the refrigerant, so that the second operating medium is lubrication oil enriched compared to the first operating medium, wherein the refrigerant compressor is configured to compress at least a portion of the first operating medium,
wherein the second operating medium has a viscosity ratio of κ<1 in a first operating state of the cooling system and serves for lubricating at least one bearing site of a rotor of the refrigerant compressor,
wherein the at least one bearing site comprises at least one angular ball bearing, which comprises an inner ring, an outer ring and balls rolling therebetween, and
wherein the inner ring and/or the outer ring comprise a nitrided or carbonitrided or case-hardened raceway.

2. The cooling system according to claim 1 , wherein the refrigerant includes derivatives of alkenes.

3. The cooling system according to claim 2 , wherein the refrigerant includes Hydrofluorooelfins (HFOs) and/or Hydrochlorofluorooelfins (HCFOs).

4. The cooling system according to claim 1 , wherein the oil separator reduces the percentage of the refrigerant in the operating medium such that the second operating medium comprises between 15% by weight and 30% by weight of the refrigerant.

5. The cooling system according to claim 1 , wherein a joint operating medium circuit of the first and second operating medium is provided, wherein the at least one bearing site is sealed against the first operating medium.

6. The cooling system according to claim 1 , wherein the at least one angular ball bearing comprises an inner ring, an outer ring and balls rolling between, wherein the inner ring and/or the outer ring comprise a burnished raceway.

7. The cooling system according to claim 1 , wherein the at least one bearing site comprises a second bearing, wherein the second bearing is a cylindrical roller bearing.

8. The cooling system according to claim 7 , wherein at least one raceway of the second bearing is cabronitrided and/or burnished and/or at least one rolling elements of the second bearing consists of a ceramic.

9. The cooling system according to claim 8 , wherein the ceramic is silicon nitride Si3N4.

10. The cooling system according to claim 1 , wherein, during operation of the cooling system, the refrigerant compressor is configured to be operated with variable operation speeds.

11. The cooling system according to claim 1 , wherein the viscosity ratio of the second operating medium is κ>1 in a second operating state of the cooling system, the second operating state corresponding to a higher rotational speed of the refrigerant compressor, a lower temperature thereof, or both as compared to the first operating state.

12. The cooling system of claim 1 , wherein the oil separator is configured to produce the first operating medium having between 98% by weight of the refrigerant and 99.5% by weight of the refrigerant.

13. The cooling system of claim 1 , further comprising a condenser configured to condense the operating medium, wherein the oil separator is downstream from the condenser and upstream from the refrigerant compressor.

14. The cooling system of claim 1 , further comprising a condenser configured to condense the operating medium, wherein the oil separator is integrated into the condenser.

15. The cooling system of claim 1 , wherein the oil separator is configured to decrease a refrigerant composition of the second operating medium in response to a decrease in temperature at the at least one bearing site.

16. The cooling system of claim 1 , wherein the oil separator is downstream from a pressurized outlet of the refrigerant compressor, wherein the second operating medium is fed back to the refrigerant compressor from the oil separator, and wherein at least a portion of the second operating medium mixes with the first operating medium in, or upstream of a suction inlet of, the refrigerant compressor.

17. A method, comprising:
separating; using an oil separator, a combined operating media comprising refrigerant and lubrication oil, to produce the first operating medium and the second operating medium, the second operating medium having a refrigerant content of between 15% by weight and 50% by weight and being lubrication oil enriched as compared to the first operating medium;
lubricating at least one bearing site of a refrigerant compressor using the second operating medium, wherein the second operating medium in the at least one bearing site has a viscosity ratio of κ<1 when the refrigerant compressor is in a first operating state;
compressing at least the first operating medium by operating the refrigerant compressor in the first operating state;
mixing the first and second operating media to produce the combined operating media; and
feeding the combined operating media to the oil separator.

18. The method of claim 17 , further comprising cooling the mixture of the first and second operating media in a condenser that is upstream of the oil separator and downstream from the refrigerant compressor.

19. The method of claim 17 , further comprising compressing at least the first operating medium using the refrigerant compressor in a second operating state that corresponds to a higher speed, lower temperature, or both in comparison to the first operating state, wherein the second operating medium in the at least one bearing site has a viscosity ratio of κ>1 when the refrigerant compressor is in the second operating state.

20. The method of claim 17 , further comprising increasing the refrigerant content of the second operating medium in response to a decrease in temperature at the at least one bearing site, to decrease the viscosity ratio of the second operating medium at the at least one bearing site.

Assignees

• Skf Ab

Inventors

• Hauleitner Rudolf
• Kammerhuber Mario
• Morales Espejel Guillermo
• Wallin Hans

Classifications

• F25B2500/16

  Lubrication · CPC title

• F25B31/004 Primary

  oil recirculating arrangements · CPC title

• F25B43/02

  for separating lubricants from the refrigerant · CPC title

• F25B13/00

  Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) · CPC title

• F25B1/047 Primary

  of screw type · CPC title