Intermediate discharge port for a compressor

Patent metadata

Field	Value
Publication number	US-11022122-B2
Application number	US-201715611137-A
Country	US
Kind code	B2
Filing date	Jun 1, 2017
Priority date	Jun 1, 2016
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

A screw compressor includes a compressor housing defining a working chamber, the housing including a plurality of bores; a first rotor having helical threads, the first rotor being housed in a first of the plurality of bores; a second rotor having helical threads intermeshing with the helical threads of the first rotor, the second rotor being housed in a second of the plurality of bores; an inlet port that receives a fluid to be compressed; an outlet port that receives a compressed fluid; and an intermediate discharge port disposed between the compression chamber and the outlet port, the intermediate discharge port including a sealing member and a biasing mechanism, fluid flow being prevented between the compression chamber and the intermediate discharge port when in a flow-blocked state, and fluid flow being enabled from the compression chamber through the intermediate discharge port when in a flow-permitted state.

First claim

The invention claimed is:

1. A screw compressor, comprising:
a compressor housing defining a working chamber, the housing including a plurality of bores;
a first rotor having helical threads, the first rotor being housed in a first of the plurality of bores;
a second rotor having helical threads intermeshing with the helical threads of the first rotor, the second rotor being housed in a second of the plurality of bores;
an inlet suction port that receives a fluid to be compressed;
an outlet discharge port that receives a compressed fluid;
a compression chamber formed by the intermeshing of the helical threads of the first rotor and the helical threads of the second rotor between the inlet suction port and the outlet discharge port; and
an intermediate discharge port fluidly connectable to the compression chamber and disposed between the inlet suction port and the outlet discharge port and spaced from the outlet discharge port,
the intermediate discharge port being disposed at a top portion of the compressor housing so that a piston included in the intermediate discharge port is fluid-forced vertically upward or downward to selectively transition the intermediate discharge port between a flow-blocked state and a flow-permitted state, based on an operating pressure ratio of the compressor, the operating pressure ratio between fluid in the compression chamber and the compressed fluid at the outlet discharge port,
the intermediate discharge port including a sealing member having a sealing surface that follows a contour of the first bore and the second bore and forms a sealing engagement with a surface within the intermediate discharge port when biased by the piston to be in the flow-blocked state so that fluid flow is prevented between the compression chamber and the intermediate discharge port when in the flow-blocked state, and fluid flow being enabled from the compression chamber through the intermediate discharge port when biased by the piston to be in the flow-permitted state in which the sealing surface is disengaged from sealing engagement with the surface within the intermediate discharge port,
the sealing surface being disposed at a first vertical distance from the compression chamber when in the flow-blocked state and a second vertical distance from the compression chamber when in the flow permitted state, the first vertical distance being relatively smaller than the second vertical distance.

2. The screw compressor according to claim 1 , wherein the intermediate discharge port is disposed at a location of the compression chamber at which a fluid being compressed is partially compressed.

3. The screw compressor according to claim 1 , wherein the screw compressor includes a plurality of intermediate discharge ports disposed between the inlet suction port and the outlet discharge port, the plurality of intermediate discharge ports being disposed at different locations along the compression chamber between the inlet suction port and the outlet discharge port.

4. The screw compressor according to claim 1 , wherein the compressor housing includes a plurality of apertures configured to fluidly connect the compression chamber and the intermediate discharge port when in the flow-permitted state.

5. The screw compressor according to claim 1 , wherein the compressor housing includes a single aperture configured to fluidly connect the compression chamber and the intermediate discharge port when in the flow-permitted state.

6. The screw compressor according to claim 5 , wherein the single aperture is formed in a wall of the housing, a portion of the single aperture being in the first of the plurality of bores and another portion of the single aperture being in the second of the plurality of bores.

7. A heating, ventilation, and air conditioning (HVAC) system, comprising:
a condenser, an expansion device, and an evaporator, and a screw compressor fluidly connected and forming a heat transfer circuit, wherein the screw compressor includes:
a compressor housing defining a working chamber, the housing including two bores;
a first rotor having helical threads, the first rotor being housed in a first of the two bores;
a second rotor having helical threads intermeshing with the helical threads of the first rotor, the second rotor being housed in a second of the two bores;
an inlet suction port that receives a fluid to be compressed;
an outlet discharge port that receives a compressed fluid;
a compression chamber formed by the intermeshing of the helical threads of the first rotor and the helical threads of the second rotor between the inlet suction port and the outlet discharge port; and
an intermediate discharge port fluidly connectable to the compression chamber and disposed between the inlet suction port and the outlet discharge port and spaced from the outlet discharge port,
the intermediate discharge port being disposed at a top portion of the compressor housing so that a piston included in the intermediate discharge port is fluid-forced vertically upward or downward to selectively transition the intermediate discharge port between a flow-blocked state and a flow-permitted state, based on an operating pressure ratio of the compressor, the operating pressure ratio between fluid in the compression chamber and the compressed fluid at the outlet discharge port,
the intermediate discharge port including a sealing member having a sealing surface that follows a contour of the first bore and the second bore and forms a sealing engagement with a surface within the intermediate discharge port when biased by the piston to be in the flow-blocked state so that fluid flow is prevented between the compression chamber and the intermediate discharge port when in the flow-blocked state, and fluid flow being enabled from the compression chamber through the intermediate discharge port when biased by the piston to be in the flow-permitted state in which the sealing surface is disengaged from sealing engagement with the surface within the intermediate discharge port,
the sealing surface being disposed at a first vertical distance from the compression chamber when in the flow-blocked state and a second vertical distance from the compression chamber when in the flow-enabled state, the first vertical distance being relatively smaller than the second vertical distance.

8. The HVAC system according to claim 7 , wherein the piston of the intermediate discharge port is controlled based on a pressure ratio between a fluid in the compression chamber and the compressed fluid at the outlet discharge port.

9. The HVAC system according to claim 7 , wherein the intermediate discharge port is in the flow-blocked state when the screw compressor is operating at a full-load.

10. The HVAC system according to claim 7 , wherein the intermediate discharge port is in the flow-permitted state when the screw compressor is operating at a partial load.

11. The HVAC system according to claim 7 , wherein the intermediate discharge port is disposed at a location of the compression chamber at which a fluid being compressed is partially compressed.

12. The HVAC system according to claim 7 , wherein the screw compressor includes a plurality of intermediate discharge ports disposed between the inlet suction port and the outlet discharge port, the plurality of intermediate discharge ports being disposed at different locations along the compression chamber between the inlet suction port and the outlet discharge port.

13. The HVAC system according to claim 7 , wherein the compressor housing includes a plurality of apertures configured to fluidly connect the compression chamber and the intermediate discharge p

Assignees

• Trane Int Inc

Inventors

• Branch Scott M
• Hagen Timothy S
• Rood Jerry A
• Scala Alberto

Classifications

• F04C18/16 Primary

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

• F04C28/10

  characterised by changing the positions of the inlet or outlet openings with respect to the working chamber · CPC title

• F25B49/022

  Compressor control arrangements · CPC title

• F25B1/047

  of screw type · CPC title

• F25B2600/027

  by controlling pressure · CPC title