Methods and devices for cooling a motor of a refrigerating machine with liquid and economizer gas

Claim 3

A method as claimed in claim 1, comprising the steps of vaporizing at least a major quantity of liquid of the second flow in said path, and supplying to said economiser hole both the first flow and the second flow.

Claim 4

A method as claimed in claim 2, comprising the step of mixing the first flow and the second flow in the motor cavity.

Claim 5

A method as claimed in claim 1, comprising the steps of deriving said second flow from said main flow and detecting a temperature adjacent to the motor and controlling the second flow as a function of said temperature.

Claim 6

A method as claimed in claim 1 comprising the step of using said main flow as said second flow.

Claim 7

A method as claimed in claim 1, comprising the step of using as said second flow said main flow downstream of said condenser, and upstream of a gas separator performing said step of separating, in said refrigerating circuit, a substantially gaseous portion of said refrigerant fluid.

Claim 8

A method as claimed in claim 1, comprising the step of using as said second flow at least part of said main flow downstream of the compressor and upstream of a condenser of said refrigerating circuit, and injecting into said compressor liquid refrigerant in such an amount that the refrigerant fluid is wet at the compressor discharge port.

Claim 9

A method as claimed in claim 1, wherein the first flow is separated from the main flow downstream of said compressor and upstream of said evaporator.

Claim 10

A method as claimed in claim 1, wherein the first flow is separated from the main flow in a centrifugal economiser separator also urging liquid into said path.

Claim 11

A hermetic motor compressor unit comprising a rotary compressor adapted to compress a main flow of refrigerant fluid, an electric motor drivingly coupled to said rotary compressor for rotation therewith, said electric motor comprising a rotor mounted onto a shaft connecting the motor to the compressor, a stator mounted adjacent to the rotor in a motor housing connected to a casing of the compressor, separation means for separating in said refrigerant fluid a substantially gaseous portion thereof, means for supplying with said substantially gaseous portion a motor cavity provided in said housing adjacent a first side of said stator, said first side facing said rotor, conduit means connecting said motor cavity with a hole provided in the compressor casing in such a position as to be subjected, in use at full load, to a pressure intermediate between an intake pressure and a discharge pressure of the compressor, and channel means for guiding refrigerant fluid in heat exchange relationship with a second side of said stator, said second side being remote from said first side.

Claim 12

A hermetic motor compressor unit comprising a rotary compressor adapted to compress a main flow of refrigerant fluid, an electric motor drivingly coupled to said rotary compressor for rotation therewith, said electric motor comprising a rotor mounted onto a shaft connecting the motor to the compressor, a stator mounted adjacent to the rotor in a motor housing connected to a casing of the compressor, separation means for separating in said refrigerant fluid a substantially gaseous portion thereof, means for supplying with said substantially gaseous portion a motor cavity provided in said housing adjacent a first side of said stator, said first side facing said rotor, conduit means connecting said motor cavity with a hole provided in the compressor casing in such a position as to be subjected, in use at full load, to a pressure intermediate between an intake pressure and a discharge pressure of the compressor, and channel means for guiding refrigerant fluid in heat exchange relationship with a second side of said stator, said second side being remote from said first side.

Claim 13

A hermetic motor-compressor unit as claimed in claim 10, wherein the separation means are centrifugal means.

Claim 14

A hermetic motor-compressor unit as claimed in claim 11, wherein the centrifugal means have, remote from an axis thereof, an outlet which is connected to an inlet of the channel means.

Claim 15

A hermetic motor-compressor unit as claimed in claim 11, wherein the centrifugal means are mounted on a shaft of the motor, with the motor being axially between the compressor and the centrifugal means.

Claim 16

A hermetic motor-compressor unit as claimed in claim 10, wherein the separating means is a subcooler.

Claim 17

A hermetic motor-compressor unit as claimed in claim 10, wherein a downstream end of the channel means communicates with the motor cavity.

Claim 18

A hermetic motor-compressor unit as claimed in claim 15, comprising gas circulation means for guiding gas refrigerant adjacent to said second side of said stator, said gas circulation means communicating with said motor cavity.

Claim 19

A refrigerating machine comprising a hermetic motor-compressor unit comprising a rotary compressor, a refrigerating circuit mounted operatively between a discharge port and an intake port of said compressor, an electric motor drivingly coupled to said rotary compressor for rotation therewith, said electric motor comprising a motor-rotor drivingly coupled to a compressor-rotor, a stator mounted adjacent to the motor-rotor in a motor housing connected to a casing of the compressor, separation means for separating in said refrigerating circuit a substantially gaseous portion of a refrigerant fluid present in use in said circuit, means for supplying with said substantially gaseous portion a motor cavity provided in said housing adjacent a first side of said stator, said first side facing said motor-rotor, conduit means connecting said motor cavity with a hole provided in the compressor casing in such a position as to be subjected, in use at full load, to a pressure intermediate between an intake pressure and a discharge pressure of the compressor, and channel means for guiding refrigerant fluid in heat exchange relationship with said stator adjacent a second side thereof which is remote from said first side.

Claim 20

A refrigerating machine comprising a hermetic motor-compressor unit comprising a rotary compressor, a refrigerating circuit mounted operatively between a discharge port and an intake port of said compressor, an electric motor drivingly coupled to said rotary compressor for rotation therewith, said electric motor comprising a motor-rotor drivingly coupled to a compressor-rotor, a stator mounted adjacent to the motor-rotor in a motor housing connected to a casing of the compressor, separation means for separating in said refrigerating circuit a substantially gaseous portion of a refrigerant fluid present in use in said circuit, means for supplying with said substantially gaseous portion a motor cavity provided in said housing adjacent a first side of said stator, said first side facing said motor-rotor, conduit means connecting said motor cavity with a hole provided in the compressor casing in such a position as to be subjected, in use at full load, to a pressure intermediate between an intake pressure and a discharge pressure of the compressor, and channel means for guiding refrigerant fluid in heat exchange relationship with said stator adjacent a second side thereof which is remote from said first side.

Claim 21

A refrigerating machine as claimed in claim 17, wherein the separation means are centrifugal means mounted in series in said refrigerating circuit.

Claim 22

A refrigerating machine as claimed in claim 18, wherein the centrifugal means have, remote from an axis thereof, an outlet which is connected to an inlet of the channel means.

Claim 23

A refrigerating machine as claimed in claim 17, wherein the channel means are mounted in series in the refrigerating circuit.

Claim 24

A refrigerating machine as claimed in claim 20, wherein the channel means are mounted between said discharge port of the compressor and a condenser of said refrigerating circuit, and means are provided for injecting liquid in said compressor.

Claim 25

A refrigerating machine as claimed in claim 20, wherein the channel means are mounted downstream of a condenser of said refrigerating circuit and upstream of said separating means.

Claim 26

A refrigerating machine as claimed in claim 17, wherein the separating means is a subcooler having a vapour path connected to the motor cavity and a subcooled liquid path arranged in the refrigerating circuit downstream of a condenser and upstream of an expansion valve of the refrigerating circuit.