Defrosting arrangement and method for a refrigeration system

Claim 3

The method according to claim 1 including the preliminary steps of withdrawing liquid refrigerant from the receiver and passing it through the evaporator, withdrawing the liquid refrigerant from the evaporator, and collecting the liquid refrigerant withdrawn from the evaporator to establish said body of liquid refrigerant.

Claim 4

In a refrigeration system including an expansion valve, an evaporator, a compressor, a condenser communicating with the compressor discharge outlet, a receiver communicating with the condenser outlet, an accumulator arranged to receive refrigerant from the evaporator and adapted to direct gaseous refrigerant into a stream thereof, the accumulator having means for collecting a body of liquid refrigerant and means for metering liquid refrigerant from said body at a predetermined rate into said stream of gaseous refrigerant, a suction conduit for conducting said stream to the compressor suction inlet, means forming a defrost passage between the compressor discharge outlet and the evaporator inlet for bypassing gaseous refrigerant from the compressor around the expansion valve to the evaporator, and a defrost valve associated with the defrost passage for controlling the flow of refrigerant therein; the improvement comprising the feature that said means forming said defrost passage comprise the condenser, the receiver, and a defrost conduit interconnecting the receiver outlet and the evaporator inlet.

Claim 5

In a refrigeration system including an expansion valve, an evaporator, a compressor, a condenser communicating with the compressor discharge outlet, a receiver communicating with the condenser outlet, an accumulator arranged to receive refrigerant from the evaporator and adapted to direct gaseous refrigerant into a stream thereof, the accumulator having means for collecting a body of liquid refrigerant and means for metering liquid refrigerant from said body at a predetermined rate into said stream of gaseous refrigerant, a suction conduit for conducting said stream to the compressor suction inlet, means forming a defrost passage between the compressor discharge outlet and the evaporator inlet for bypassing gaseous refrigerant from the compressor around the expansion valve to the evaporator, and a defrost valve associated with the defrost passage for controlling the flow of refrigerant therein; the improvement comprising the feature that said means forming said defrost passage comprise the condenser, the receiver, and a defrost conduit interconnecting the receiver outlet and the evaporator inlet.

Claim 6

In a refrigeration system including an expansion valve, an evaporator, an accumulator, a compressor, a condenser and a receiver connected in series in a closed refrigeration circuit for normally conducting refrigerant in a refrigerating cycle; the evaporator, accumulator and compressor also being connected in a closed defrost circuit for alternatively conducting refrigerant in a defrosting cycle; the accumulator being adapted to direct relatively low pressure gaseous refrigerant into a stream thereof, the accumulator having means for collecting a body of liquid refrigerant and means for metering liquid refrigerant from said body at a controlled rate into said stream of gaseous refrigerant; a suction conduit for conducting said stream to the compressor suction inlet; a defrost conduit connected in the defrost circuit for bypassing relatively high pressure gaseous refrigerant from the compressor around the expansion valve to the evaporator; and a defrost valve associated with the defrost conduit and movable between a refrigerating position closing the defrost conduit to the passage of refrigerant and a defrosting position opening the defrost conduit to the passage of refrigerant; the improvement comprising the feature that the defrost conduit interconnects the receiver outlet and the evaporator inlet, whereby when the defrost valve is in its defrosting position, a defrost passage for said high pressure gaseous refrigerant is formed between the compressor discharge outlet and the evaporator inlet by the condenser, the receiver and the defrost conduit.

Claim 7

In a refrigeration system including an expansion valve, an evaporator, an accumulator, a compressor, a condenser and a receiver connected in series in a closed refrigeration circuit for normally conducting refrigerant in a refrigerating cycle; the evaporator, accumulator and compressor also being connected in a closed defrost circuit for alternatively conducting refrigerant in a defrosting cycle; the accumulator being adapted to direct relatively low pressure gaseous refrigerant into a stream thereof, the accumulator having means for collecting a body of liquid refrigerant and means for metering liquid refrigerant from said body at a controlled rate into said stream of gaseous refrigerant; a suction conduit for conducting said stream to the compressor suction inlet; a defrost conduit connected in the defrost circuit for bypassing relatively high pressure gaseous refrigerant from the compressor around the expansion valve to the evaporator; and a defrost valve associated with the defrost conduit and movable between a refrigerating position closing the defrost conduit to the passage of refrigerant and a defrosting position opening the defrost conduit to the passage of refrigerant; the improvement comprising the feature that the defrost conduit interconnects the receiver outlet and the evaporator inlet, whereby when the defrost valve is in its defrosting position, a defrost passage for said high pressure gaseous refrigerant is formed between the compressor discharge outlet and the evaporator inlet by the condenser, the receiver and the defrost conduit.

Claim 8

In a refrigeration system according to claim 4, wherein said refrigerant is present in the system in an amount sufficient to maintain a predetermined minimum level of liquid refrigerant in the receiver during operation in the refrigerating cycle, the further improvement comprising the feature that the receiver outlet is located substantially below said predetermined minimum level.