Cascaded multicircuit,multirefrigerant refrigeration system

Claim 2

A multicircuit, multirefrigerant refrigeration system comprising: a. first and second closed refrigerant circuits, each circuit having i. a compressor, ii. a condensor connected to receive refrigerant vapors under pressure from said compressor, iii. an evaporator, iv. a high-pressure line connecting from the condenser outlet to the evaporator inlet, v. a low-pressure line connecting from the evaporator outlet to the compressor inlet, b. a vapor-liquid separator in said second circuit having its inlet and vapor outlet connected in the high-pressuRe line and its liquid outlet connected to the low-pressure line, c. said second circuit being charged with a mixture of at least two refrigerants having different boiling points, d. means forming a heat exchanger between the evaporator of said first circuit and the high-pressure line of said second circuit at a point therein downstream of said separator.

Claim 3

A cascaded, multicircuit, multirefrigerant refrigeration system comprising: a. a plurality of closed refrigerant circuits, each circuit having i. a compressor, ii. a condenser connected to receive refrigerant vapors under pressure from said compressor, iii. an evaporator, iv. a high-pressure line connecting from the condenser outlet to the evaporator inlet, v. a low-pressure line connecting from the evaporator outlet to the compressor inlet, vi. a plurality of separator stages successively connected between said condenser and evaporator, each stage having a vapor-liquid separator having its inlet and vapor outlet connected in said high-pressure line and means connecting between the fluid outlet of said separator and said low-pressure line to expand liquid refrigerant and to exchange heat between the high-pressure line downstream of said separator and the expanded refrigerant, b. means forming a heat exchanger between the evaporator of a circuit and the high-pressure line of the next successive circuit at a point therein downstream of the first vapor-liquid separator therein, c. each circuit having a mixture of refrigerants therein, said refrigerants in circuit being one more in number than the number of separator stages therein and having different boiling points at the same pressure, d. i. the highest-boiling-point refrigerant in each circuit having a boiling point sufficiently high to enable said refrigerant to condense prior to delivery to the first vapor-liquid separator in said circuit, ii. the difference between the highest and lowest boiling point of the refrigerants in each circuit being progressively greater for each circuit, iii. the boiling point of the lowest-boiling-point refrigerant being progressively lower for each circuit.

Claim 4

A cascaded, multicircuit, multirefrigerant refrigeration system comprising: a. a plurality of closed refrigerant circuits, each circuit having i. a compressor, ii. a condenser connected to receive refrigerant vapors under pressure from said compressor, iii. an evaporator, iv. a high-pressure line connecting from the condenser outlet to the evaporator inlet, v. a low-pressure line connecting from the evaporator outlet to the compressor inlet, vi. a plurality of separator stages successively connected between said condenser and evaporator, each stage having a vapor-liquid separator having its inlet and vapor outlet connected in said high-pressure line and means connecting between the fluid outlet of said separator and said low-pressure line to expand liquid refrigerant and to exchange heat between the high-pressure line downstream of said separator and the expanded refrigerant, b. means forming a heat exchanger between the evaporator of a circuit and the high-pressure line of the next successive circuit at a point therein downstream of the first vapor-liquid separator therein, c. each circuit having a mixture of refrigerants therein, said refrigerants in circuit being one more in number than the number of separator stages therein and having different boiling points at the same pressure, d. i. the highest-boiling-point refrigerant in each circuit having a boiling point sufficiently high to enable said refrigerant to condense prior to delivery to the first vapor-liquid separator in said circuit, ii. the difference between the highest and lowest boiling point of the refrigerants in each circuit being progressively greater for each circuit, iii. the boiling point of the lowest-boiling-point refrigerant being progressively lower for each circuit.

Claim 5

A refrigeration system as set forth in claim 2 and further including means forming a heat exchange between the low-pressure line of one circuit and the high-pressure line of another circuit.

Claim 6

A refrigeration system as set forth in claim 2 wherein the lowest-boiling-point refrigerant of the last circuit is selected from the group consisting of neon, hydrogen and helium.

Claim 7

A refrigeration system as set forth in claim 2 wherein all of the compressors are of the hermetic oil-lubricated type.

Claim 8

A refrigeration system as set forth in claim 5 wherein the highest-boiling-point refrigerant in each circuit is a halocarbon.

Claim 9

A refrigeration system as set forth in claim 5 wherein the lowest-boiling-point refrigerant of the last circuit is selected from the group consisting of neon, hydrogen and helium.

Claim 10

A refrigeration system as set forth in claim 7 wherein the highest-boiling-point refrigerant in each circuit is a halocarbon.

Claim 11

A refrigeration system as set forth in claim 5 and further including means for exchanging heat between the low-pressure line of one circuit and the high-pressure line of another circuit.

Claim 12

A refrigeration system as set forth in claim 9 wherein said means for exchanging heat is located in the high-pressure line of the next successive circuit, upstream of said first separator therein and is located in said low-pressure line at a point therein where the temperature in said low-pressure line is above the freezing point of the oil used to lubricate the compressor in said next successive circuit.