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US 4,787,211 AGranted
Refrigeration system
AssigneeCopeland Corporation
InventorDavid N. Shaw
Life of this patent
Estimating the term…
Abstract
There is disclosed a refrigeration system employing multi-stage compressors, several unique modes of operation thereof, a sub-cooler/economizer for sub-cooling the condensed refrigerant prior to vaporization in the evaporator, as well as an improved expansion valve arrangement for controlling second stage discharge temperature, another valve arrangement for controlling economizer liquid discharge temperature, an interstage intercooler for use in a hot water system, a satellite compressor arrangement for ultra-low temperature applications, and an improved liquid-suction heat exchange arrangement.
Claims42
A system comprising:
- a variable capacity first stage compressor;
- at least two second stage compressors;
- conduit means bearing a compressible refrigerant connecting said first stage compressor to said second stage compressors, said second stage compressors being connected in parallel with each other;
- motors for driving said compressors;
- and
- control means for controlling said first stage compressor and said second stage compressors, said control means being operable to vary the capacity of said first stage compressor while said second stage compressors are operating, to shut down one of said second stage compressors when the capacity of said first stage compressor reaches a predetermined minimum and thereafter to increase the capacity of said first stage compressor while continuing to operate the remaining second stage compressors.
3 more elements
A refrigeration system comprising:
- a first stage variable speed compressor;
- second stage variable capacity compressor means;
- conduit means bearing a compressible refrigerant interconnecting said first stage compressor with said second stage compressor means;
- and
- control means for modulating the capacity of said second stage compressor means in response to a parameter which parallels a condition in said conduit means;
- a condenser and an evaporator operatively connected in series between the discharge outlet of said second stage compressor means and the suction inlet of said first stage compressor;
- a refrigerant subcooler for subcoling refrigerant flowing from said condenserto said evaporator;
- said subcooler normally expanding a portion of the condensed refrigerant downstream of said condenser for subcooling refrigerant flowing to said evaporator, and
- means for feeding said expanded portion of refrigerant to said conduit means between the outlet of said first stage compressor means and the inlet of said second stage compressor means.
6 more elements
A refrigerant compressing system comprising:
- a first stage variable speed compressor;
- second stage variable capacity compressor means;
- conduit means bearing a compressible refrigerant interconnecting said first stage compressor with said second stage compressor means;
- and
- control means for modulating the capacity of said second stage compressor means in response to the speed at which said first stage compressor is operating.
2 more elements
A refrigerant compressing system comprising:
- a first stage variable speed compressor;
- second stage variable capacity compressor means;
- conduit means bearing a compressible refrigerant interconnecting said first stage compressor with said second stage compressor means;
- and
- control means for modulating the capacity of said second stage compressor means in response to the power consumption of said first stage compressor.
2 more elements
A sysem comprising:
- variable capacity first stage compressor means;
- variable capacity second stage compressor means;
- conduit means bearing a compressible refrigerant connecting said first stage compressor means to said second stage compressor means;
- motor means for powering said first and second stage compressor means;
- control means for controlling said motor means, said control means being operable to vary the capacity of both of said stages and to totally shut down one of said stages;
- means permitting refrigerant to bypass said one of said stages when shut down.
3 more elements
A method for controlling a system including a variable capacity first stage compressor and two second stage motor compressors connected in parallel with one another, said method comprising the following steps:
- (a) in response to decreasing system load first reducing the capacity of one of said stages;
- (b) upon further decrease in system load reducing the capacity of the other of said stages;
- (c) upon further decrease in system load reducing the capacity of either one of said stages to minimum;
- and
- (d) thereafter modulating the remaining operating stage to match system load.
2 more elements
A system comprising:
- (a) first stage compressor means including at least one variable speed motor-compressor;
- (b) second stage compressor means including at least one variable speed motor-compressor in fluid communication with said first stage compressor means;
- and
- (c) power supply means for supplying power to each of said motor-compressors, said power supply means including
- (1) a variable speed motor controller normally connected to said first stage motor-compressor to vary the capacity thereof, and
- (2) means for de-energizing said first stage motor-compressor and for connecting said motor controller to said second stage motor-compressor to vary the capacity thereof at low system load conditions.
3 more elements
A method for controlling a system including two variable speed motor compressors connected in series, and a single inverter, said system being operable in a normal-load range and in a low-load range, said method comprising the following steps:
- (a) operating both compressors when the system load is in said normal-load range with said inverter varying the speed of the first motor-compressor to vary its refrigeration capacity in response to system load;
- (b) de-energizing said first motor-compressor when the system load drops below a certain first load point;
- and
- (c) thereafter connecting said inverter to the second compressor to vary its refrigeration capacity in response to system load.
1 more element
A system comprising:
- (a) At least two first stage motor-compressors, at least one of said first stage motor-compressors being a variable speed motor-compressor, both of said first stage motor-compressors being connected in parallel;
- (b) second stage compressor means;
- (c) conduit means bearing a compressible refrigerant connecting said first stage motor-compressors to said second stage compressor means;
- (d) inverter drive means for normally powering said variable speed first stage motor-compressor and the other of said motor-compressors being normally line powered;
- and
- (e) control means for controlling said two motor-compressors, said control means including said inverter means.
3 more elements
Dependencies are inferred from the claim text.