Refrigerant flow rate control based on liquid level in dual evaporator two-stage refrigeration cycles
First Claim
1. A refrigeration system for use in a refrigerator having a freezer compartment and a fresh food compartment, said refrigeration system comprising:
- first and second compressors;
a condenser;
a first expansion device;
a first evaporator for providing cooling to the fresh food compartment;
a phase separator connected to receive refrigerant from said first evaporator;
a second expansion device comprising a pulse width modulated solenoid valve;
a second evaporator for providing cooling to the freezer compartment, all the above elements connected together in series, in that order, said phase separator having a first outlet for supplying liquid refrigerant to said pulse width modulated solenoid valve and a second outlet for supplying gaseous refrigerant to said second compressor;
a liquid level sensor disposed in said phase separator; and
a controller for controlling the duty cycle of said pulse width modulated solenoid valve, said controller having an input connected to said liquid level sensor.
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Accused Products
Abstract
Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system using a dual evaporator, two-stage cycle. The refrigeration cycle includes a phase separator which receives two phase refrigerant from the low temperature evaporator and supplies liquid refrigerant to the pulse width modulated solenoid valve. A liquid level sensor is disposed in the phase separator, and a controller for controlling the duty cycle of the pulse width modulated solenoid valve is provided to receive input from the liquid level sensor. The liquid level sensor can be of the type which provides a continuously variable signal as a function of liquid level, or it can be a liquid level switch which controls valve duty cycle on the basis of whether the phase separator liquid level is above or below a set level. Alternatively, two liquid level switches can be provided.
118 Citations
7 Claims
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1. A refrigeration system for use in a refrigerator having a freezer compartment and a fresh food compartment, said refrigeration system comprising:
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first and second compressors; a condenser; a first expansion device; a first evaporator for providing cooling to the fresh food compartment; a phase separator connected to receive refrigerant from said first evaporator; a second expansion device comprising a pulse width modulated solenoid valve; a second evaporator for providing cooling to the freezer compartment, all the above elements connected together in series, in that order, said phase separator having a first outlet for supplying liquid refrigerant to said pulse width modulated solenoid valve and a second outlet for supplying gaseous refrigerant to said second compressor; a liquid level sensor disposed in said phase separator; and a controller for controlling the duty cycle of said pulse width modulated solenoid valve, said controller having an input connected to said liquid level sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification