Direct drive refrigerant screw compressor with refrigerant lubricated bearings

Patent metadata

Field	Value
Publication number	US-11959484-B2
Application number	US-202016973710-A
Country	US
Kind code	B2
Filing date	May 20, 2020
Priority date	May 20, 2019
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

Disclosed is a direct-drive refrigerant screw compressor, having: a housing; a compression chamber in the housing; a pair of rotors, each rotor of the pair of rotors being rotationally disposed in the compression chamber and including an outer surface with a screw-geared profile; wherein, for each rotor, the compressor includes: a plurality of bearing packs disposed within a respective plurality of bearing chambers; a working fluid disposed within each of the plurality of bearing chambers, the working fluid providing oil-free lubrication to the plurality of bearing packs; a plurality of bearing lubrication ports extending through the housing and into each of the plurality of bearing chambers, and configured for injecting the working fluid into each of the plurality of bearing chambers when the compressor is running.

First claim

We claim:

1. A direct-drive refrigerant screw compressor, comprising:
a housing;
a compression chamber in the housing;
a pair of rotors including first and second rotors, each of the first and second rotors of the pair of rotors being rotationally disposed in the compression chamber and including an outer surface with a screw-geared profile;
wherein, for each of the first and second rotors, the compressor includes:
a plurality of bearing packs disposed within a respective plurality of bearing chambers;
a working fluid disposed within each of the plurality of bearing chambers, the working fluid providing oil-free lubrication to the plurality of bearing packs;
a plurality of bearing lubrication ports extending through the housing and into each of the plurality of bearing chambers, and configured for injecting the working fluid into each of the plurality of bearing chambers when the compressor is running,
wherein the plurality of bearing chambers includes a forward bearing chamber and an aft bearing chamber; and
the plurality of bearing lubrication ports includes, for directing the working fluid into the respective plurality of bearing chambers:
for the first rotor, a first forward bearing lubrication port and a first aft bearing lubrication port; and
for the second rotor, a second forward bearing lubrication port and a second aft bearing lubrication port, and
wherein the plurality of bearing lubrication ports includes a respective plurality flow control orifices to reduce a flow volume or rate from a condenser, wherein the respective plurality flow control orifices are defined in the compressor housing.

2. The compressor of claim 1 , wherein for each of the first and second rotors:
the compressor includes a lubricant drain port for draining the working fluid from the plurality of bearing chambers when the compressor is running.

3. The compressor of claim 2 , wherein for each of the first and second rotors:
the lubricant drain port extends into the aft bearing chamber and is fluidly connected to the forward bearing chamber through the compression chamber.

4. A refrigerant system comprising:
a condenser; and
a direct-drive refrigerant screw compressor, comprising:
a housing;
a compression chamber in the housing;
a pair of rotors including first and second rotors, each of the first and second rotors of the pair of rotors being rotationally disposed in the compression chamber and including an outer surface with a screw-geared profile;
wherein, for each of the first and second rotors, the compressor includes:
a plurality of bearing packs disposed within a respective plurality of bearing chambers;
a working fluid disposed within each of the plurality of bearing chambers for providing oil-free lubrication to the plurality of bearing packs;
a plurality of bearing lubrication ports extending through the housing and into each of the plurality of bearing chambers, and configured for injecting the working fluid into each of the plurality of bearing chambers when the compressor is running; and
a condenser conduit fluidly connecting condenser to the plurality of bearing lubrication ports,
wherein the plurality of bearing chambers includes a forward bearing chamber and an aft bearing chamber; and
the plurality of bearing lubrication ports includes, for directing the working fluid into the respective plurality of bearing chambers:
for the first rotor, a first forward bearing lubrication port and a first aft bearing lubrication port; and
for the second rotor, a second forward bearing lubrication port and a second aft bearing lubrication port, and
wherein the plurality of bearing lubrication ports includes a respective plurality flow control orifices to reduce a flow volume or rate from a condenser, wherein the respective plurality flow control orifices are defined in the compressor housing.

5. The system of claim 4 , wherein for each of the first and second rotors:
the compressor includes a lubricant drain port for draining the working fluid from the plurality of bearing chambers when the compressor is running.

6. The system of claim 5 , wherein for each of the first and second rotors:
the lubricant drain port extends into the aft bearing chamber and is fluidly connected to the forward bearing chamber through the compression chamber.

7. The system of claim 6 , wherein:
the condenser conduit includes a forward branch and an aft branch for injecting in parallel the working fluid to each forward bearing chamber and each aft bearing chamber in the compressor; and
each branch includes a plurality of sub-branches for injecting in parallel the working fluid to the bearing chambers on each branch.

8. The system of claim 7 , further comprising:
an evaporator; and
an evaporator conduit fluidly connected between the evaporator and the lubricant drain port.

9. A method of directing working fluid in a direct-drive refrigerant screw compressor, wherein for each of first and second rotors of a pair of rotors in the compressor, the method comprises:
receiving working fluid at a plurality of bearing lubrication ports in a housing of the compressor, wherein the working fluid is oil-free; and
directing the working fluid from the plurality of bearing lubrication ports to a plurality of bearing chambers; and
when the compressor is running, lubricating a plurality of bearing packs in the respective plurality of bearing chambers with the working fluid,
wherein the plurality of bearing chambers includes a forward bearing chamber and an aft bearing chamber; and
the plurality of bearing lubrication ports includes, for directing the working fluid into the respective plurality of bearing chambers:
for the first rotor, a first forward bearing lubrication port and a first aft bearing lubrication port; and
for the second rotor, a second forward bearing lubrication port and a second aft bearing lubrication port, and
wherein the plurality of bearing lubrication ports includes a respective plurality flow control orifices to reduce a flow volume or rate from a condenser, wherein the respective plurality flow control orifices are defined in the compressor housing, and
the method further comprises injecting the working fluid into a forward bearing chamber from the first and second forward bearing lubrication ports and an aft bearing chamber from the first and second aft bearing lubrication ports.

10. The method of claim 9 , wherein for each of the first and second rotors the method includes:
draining the working fluid through a lubricant drain port from the plurality of bearing chambers when the compressor is running.

11. The method of claim 10 , wherein:
for each of the first and second rotors, the forward and aft bearing chambers are fluidly connected through the compression chamber, and the lubricant drain port is disposed in the aft bearing chamber; and
the method comprises:
draining the working fluid from each bearing chamber through the lubricant drain port in the aft bearing compartment.

12. The method of claim 11 , wherein for each of the first and second rotors the method includes:
transporting the working fluid from a condenser of a refrigeration system to the plurality of bearing lubrication ports.

13. The method of claim 12 , further comprising:
transporting the working fluid in the condenser conduit so that the working fluid is injected in parallel to each forward bearing chamber and each aft bearing chamber in the compressor.

14. The method of claim 13 , wherein for each of the first and second rotors the method includes:
transporting the working fluid from the lubrication drain port to an evaporat

Assignees

• Carrier Corp

Inventors

• Qiu Yifan
• Rockwell David M
• Vaidya Amit

Classifications

• F04C29/02 Primary

  Lubrication (of machines or engines in general F01M); Lubricant separation (separation in general B01D) · CPC title

• F04C18/16

  with helical teeth, e.g. chevron-shaped, screw type {(for non-parallel axes of movement F04C18/48)} · CPC title

• F25B31/002

  Lubrication · CPC title

• F04C2240/20

  Rotors · CPC title

• F04C2240/30

  Casings or housings · CPC title