Compressor and oil drain system

1. A compressor system, comprising:

a compressor, comprising a plurality of intermeshing compressor elements, each intermeshing compressor element having a first end and a second end;

a first plurality of oil-lubricated bearings supporting the first end of each intermeshing compressor element;

a second plurality of oil-lubricated bearings supporting the second end of each intermeshing compressor element;

a compressor housing radially encompassing the intermeshing compressor elements between the first ends and the second ends;

a passage formed within the compressor housing and spaced apart from the intermeshing compressor elements, the passage extending through the housing between the first ends and the second ends of the intermeshing compressor elements, wherein the passage is structured to drain oil from at least one of the first plurality of oil-lubricated bearings and the second plurality of oil-lubricated bearings; and

a first gear, and a second gear driven by the first gear, wherein the first gear is coupled to a first intermeshing compressor element, wherein the second gear is coupled to a second intermeshing compressor, and wherein the passage is operative to drain oil used to lubricate the first gear and the second gear;

wherein the passage includes a single discharge opening, and is operative to drain oil used to lubricate the first plurality of oil-lubricated bearings and the second plurality of oil-lubricated bearings, and to discharge the drained oil through the single discharge opening;

a gearbox directly connected between the compressor housing and an oil tank; and

an internal second passageway in the gearbox configured to connect the single discharge opening of the compressor housing to the oil tank without the use external plumbing conduits.

2. The compressor system of claim 1 , further comprising a first sump and a second sump, wherein the first sump is disposed adjacent to the first ends of the intermeshing compressor elements and houses the first plurality of oil-lubricated bearings; and wherein the second sump is disposed adjacent to the second ends of the intermeshing compressor elements and houses the second plurality of oil-lubricated bearings, wherein the passage extends between the first sump and the second sump, is in fluid communication with both the first sump and the second sump, and is operative to drain oil from the first sump and the second sump.

3. The compressor system of claim 2 , wherein one of the first sump and the second sump is at least partially disposed within a cast discharge housing.

4. The compressor system of claim 1 , wherein the compressor housing further comprises a cast rotor housing and a cast discharge housing, wherein the passage is formed of a first cast passage in the cast rotor housing and a second cast passage in the cast discharge housing.

5. The compressor system of claim 1 , wherein the compressor system is configured as an oil-free screw compressor system.

6. The compressor system of claim 1 , wherein the compressor housing includes a casting; and wherein the passage is a cast passage within the casting.

7. The compressor system of claim 1 , wherein the passage is a first passage, further comprising a built-in second passage in the at least one of the gearbox and the oil tank for draining oil from the compressor; wherein the first passage includes the single discharge opening in direct fluid communication with the built-in second passage and is operative to discharge the drained oil into the built-in second passage.

8. The compressor system of claim 1 , wherein the passage is structured to drain lubrication oil from at least one of the first plurality of oil-lubricated bearings and the second plurality of oil-lubricated bearings when the compressor is installed in a first orientation and also when the compressor is installed in a second orientation rotationally displaced from the first orientation.

9. The compressor system of claim 8 , wherein the passage is structured to drain oil from the first plurality of oil-lubricated bearings and the second plurality of oil-lubricated bearings when the compressor is installed in a first orientation and also when the compressor is installed in a second orientation rotationally displaced 90° from the first orientation.

10. The compressor system of claim 1 , wherein the single discharge opening includes one of a circular, fan, or partial annular cross-sectional shape.

11. An oil-free screw compressor, comprising:

a plurality of intermeshing compressor elements, each intermeshing compressor element having a first end and a second end;

a first plurality of oil-lubricated bearings supporting the first ends of each intermeshing compressor element;

a second plurality of oil-lubricated bearings supporting the second ends of each intermeshing compressor element;

a compressor housing radially encompassing the intermeshing compressor elements between the first ends and the second ends;

a passage formed within the compressor housing and spaced apart radially from the intermeshing compressor elements, wherein the passage is structured to drain oil from at least of the first plurality of oil-lubricated bearings and to the second plurality of oil-lubricated bearings; and

a first gear, and a second gear driven by the first gear, wherein the first gear is coupled to a first intermeshing compressor element, wherein the second gear is coupled to a second intermeshing compressor element, and wherein the passage is operative to drain oil used to lubricate the first gear and the second gear;

a gearbox having built-in first and second drain passages coupled between the compressor housing and an oil tank, wherein the compressor is structured to drain oil from the at least one of the first plurality of oil-lubricated bearings and the second plurality of oil-lubricated bearings into the gearbox and then into the oil tank without the use of external plumbing; and

wherein the passage in the compressor housing and built-in first drain passage are configured to drain oil into the oil tank when the compressor housing is installed in a first position and a first rotational orientation and wherein the passage in the compressor housing and built-in second drain passage are configured to drain oil into the oil tank when the compressor housing is installed in a second position and second rotational orientation different from the first position and first rotational orientation.

12. The compressor of claim 11 , wherein the passage is operative to drain oil from the first gear, the second gear, the first plurality of oil-lubricated bearings and the second plurality of oil-lubricated bearings, and is structured to discharge the drained oil through a single discharge opening.

13. The compressor system of claim 12 , wherein the single discharge opening includes one of a circular, fan, or partial annular cross-sectional shape.

14. The compressor of claim 11 , further comprising a first sump and a second sump, wherein the first sump is disposed adjacent to the first ends of the intermeshing compressor elements and houses the first plurality of oil-lubricated bearings; and wherein the second sump is disposed adjacent to the second ends of the intermeshing compressor elements and houses the second plurality of oil-lubricated bearings; wherein the passage is in fluid communication with the first sump and the second sump, and is structured to drain oil from the first sump and the second sump.

15. The compressor of claim 11 , wherein the compressor housing includes a casting; and wherein the passage is a cast passage within the casting.

16. The compressor of claim 15 , wherein the compressor housing includes a cast rotor housing and a cast discharge housing attached to the cast rotor housing, wherein the passage is formed of a first cast passage in the cast rotor housing and a second cast passage in the cast discharge housing.

17. The compressor of claim 11 , wherein the passage is positioned to drain oil from the first plurality of oil-lubricated bearings and the second plurality of oil-lubricated bearings when the compressor is installed in a first orientation and also when the compressor is installed in a second orientation rotationally displaced 90° from the first orientation.

18. A compressor system, comprising:

a plurality of intermeshing compressor elements, each intermeshing compressor element having a first end and a second end;

a first plurality of oil-lubricated bearings supporting the first end of each intermeshing compressor element;

a second plurality of oil-lubricated bearings supporting the second end of each intermeshing compressor element;

a compressor housing radially encompassing the intermeshing compressor elements between the first ends and the second ends; and

a passage for draining oil from the first plurality of oil-lubricated bearings, from the second plurality of oil-lubricated bearings, and from a first gear and a second gear connected to the compressor elements;

wherein the passage is structured to discharge the drained oil through a single discharge opening; and

wherein the single discharge opening includes one of a fan or partial annular cross-sectional shape.