Refrigeration system with hot gas defrosting

Claim 2

A refrigeration system having multiple refrigerated fixtures with hot gas type defrosting of such fixtures, comprising, compressor means for compressing refrigerant and having low pressure suction and high pressure discharge sides, condenserreceiver means for condensing the compressed refrigerant and supplying liquid refrigerant, a plurality of evaporators associated with the refrigerated fixtures and having means normally connecting said evaporators in parallel between said condenser-receiver means and said suction side of the compressor means with means for evaporating the refrigerant and cooling said fixtures, a chamber means for separating liquid and gaseous refrigerant, valve and conduit means connecting at least one of said evaporators between the high pressure side of the system and said chamber means and operable for selectively supplying hot gaseous refrigerant to said evaporator for defrosting and for conducting the resultant liquid and gaseous refrigerant directly to said chamber means for separating the phases, said chamber means being in communication with said means normally connecting said condenser-receiver means and said evaporators for returning the resultant liquid refrigerant phase produced by defrosting from said chamber means into the liquid refrigerant supply for said evaporators, and means restrictively connecting said chamber means to the suction side of said compressor means for controllably returning the separated gaseous refrigerant from said chamber means to said compressor means.

Claim 3

The system of claim 1 wherein said means restrictively connecting said chamber means and compressor suction side includes valve means operably responsive to the presence of excess gaseous refrigerant in said chamber for controlling the communication with said compressor suction side.

Claim 4

The system of claim 2 wherein said valve means has means for controlling the pressure in said chamber means whereby the excess gaseous refrigerant is controllably removed.

Claim 5

The system of claim 1 wherein a float control means is positioned in said chamber and responsive to the liquid level therein and said means restrictively connecting said chamber means and compressor suction side includes a valve means controlled by said float control means.

Claim 6

The system of claim 1 wherein a single vessel includes both said chamber means and the refrigerant retaining receiver portion of the condenser-receiver of the system.

Claim 7

The system of claim 5 wherein said vessel is comprised of an elongated cylinder positioned horizontally, and a perforated conduit extends along the bottom of the cylinder with such perforations admitting liquid refrigerant and allowing exit of gaseous refrigerant into the vessel, said conduit having ends comprising the inlet and outlet of the refrigerant receiver formed by the vessel.

Claim 8

The system of claim 1 wherein means are provided for reducing the pressure of the liquid refrigerant supply before conducting such refrigerant to the evaporators, said chamber means being in direct communication with such reduced pressure liquid refrigerant supply between said pressure reducing means and the evaporators for receiving and separating flash gas formed in such pressure reduction, said flash gas also being removed from said chamber means by said restrictive connecting means to said compressor suction side.

Claim 9

The system of claim 7 wherein pressure reducing means produces a predetermined low pressure having a saturation temperature below normal room temperature in said liquid refrigerant supply and a predetermined pressure differential across said evaporators unrelated to the system head pressure.

Claim 10

The sYstem of claim 7 wherein said compressor means, condenser-receiver means and chamber means are all centrally located together and said evaporators and fixtures are remotely located with connecting conduits between such locations, said conduits being of reduced size comparable to the reduced refrigerant conducted by reason of eliminating said flash gas.

Claim 11

The system of claim 1 wherein said valve and conduit means includes two pressure regulating valve means operable for controlling maximum and minimum pressures for supplying said hot gaseous refrigerant for defrosting within a small predetermined pressure range under all ambient and operating conditions for controlled defrosting.

Claim 12

The system of claim 10 wherein said valve and conduit means includes another pressure regulating valve means for producing a predetermined back pressure on the refrigerant returning from defrosting.

Claim 13

The system of claim 11 wherein said other pressure regulating valve means causes a pressure reduction in the defrosting refrigerant before entering said chamber means and any resultant flash gas is separated in said chamber means.

Claim 14

The system of claim 1 wherein means are provided in said chamber means for sensing maximum and minimum desired liquid levels in said chamber means, valve controlled means connecting said chamber means to the compressor means discharge side, valve means in said means normally connecting said condenser-receiver to said evaporators upstream of the communication with said chamber means, and said sensing means operating said valve controlled means and said valve means to periodically close said valve means and open said valve controlled means upon sensing said maximum level to supply the liquid refrigerant for the evaporators from said chamber means and to reopen said valve means and close said valve controlled means upon sensing said minimum level.

Claim 15

The system of claim 13 wherein said restrictive connecting means includes a valve and pressure reducing valve means normally maintaining a pressure differential between said chamber means and normal liquid refrigerant supply, said chamber means having check valve means preventing reverse flow of refrigerant from the liquid refrigerant supply means, and said sensing means also operates said valve in said restrictive connecting means to the same positions as said valve means in said liquid supply.

Claim 16

A refrigeration system having multiple refrigerated fixtures with hot gas type defrosting of such fixtures, comprising, compressor means for compressing refrigerant and having low pressure suction and high pressure discharge sides, condenser-receiver means for condensing the compressed refrigerant and supplying liquid refrigerant, a plurality of evaporators associated with the refrigerated fixtures and having means normally connecting said evaporators in parallel between said condenser-receiver means and said suction side of the compressor means with means for evaporating the refrigerant and cooling said fixtures, a chamber means for separating liquid and gaseous refrigerant, valve and conduit means connecting at least one of said evaporators to the high pressure side of the system to supply hot gaseous refrigerant to said evaporator for defrosting and for conducting the resultant refrigerant condensate to said chamber means, said chamber means being in communication with said means normally connecting said condenser-receiver means to said evaporators for returning liquid condensate refrigerant from defrosting into the liquid refrigerant supply for said evaporators, means restrictively connecting said chamber means to the suction side of said compressor for controllably returning gaseous refrigerant from said chamber means to said compressor means, and valve means for affirmatively producing a reduced pressure in said chamber means relative to the pressure of said hot gaseous defrosting refrigerant for producing a pressure differential to cause the defrosting refrigerant to flow through the evaporators into said chAmber means.

Claim 17

A refrigeration system having multiple refrigerated fixtures with hot gas type defrosting of such fixtures, comprising, compressor means for compressing refrigerant and having low pressure suction and high pressure discharge sides, condenser-receiver means for condensing the compressed refrigerant and supplying liquid refrigerant, a plurality of evaporators associated with the refrigerated fixtures and having means normally connecting said evaporators in parallel between said condenser-receiver means and said suction side of the compressor means with means for evaporating the refrigerant and cooling said fixtures, a chamber means for separating liquid and gaseous refrigerant, valve and conduit means connecting at least one of said evaporators to the high pressure side of the system to supply hot gaseous refrigerant to said evaporator for defrosting and for conducting the resultant refrigerant condensate to said chamber means, said chamber means being in communication with said means normally connecting said condenser-receiver means to said evaporators for returning liquid condensate refrigerant from defrosting into the liquid refrigerant supply for said evaporators, means restrictively connecting said chamber means to the suction side of said compressor for controllably returning gaseous refrigerant from said chamber means to said compressor means, and valve means for affirmatively producing a reduced pressure in said chamber means relative to the pressure of said hot gaseous defrosting refrigerant for producing a pressure differential to cause the defrosting refrigerant to flow through the evaporators into said chAmber means.

Claim 18

The refrigeration system of claim 15, wherein said valve means produces a predetermined and relatively low pressure in the liquid refrigerant supply.

Claim 19

The refrigeration system of claim 15, wherein said valve means produces a predetermined pressure drop in said liquid refrigerant supply between said condenser-receiver and the location of communication of said chamber means.

Claim 20

The refrigeration system of claim 15, wherein said valve means produces a predetermined pressure differential between said compressor discharge side and said chamber means and the absolute pressures vary with discharge side pressure variations.

Claim 21

The refrigeration system of claim 15, wherein said valve means also affirmatively produces a like reduced pressure in said liquid refrigerant supply upstream of the location of said chamber means, and flash gas created by said liquid refrigerant pressure reduction is separated in said chamber means and also removed by said restrictive connecting means in a controlled manner to said compressor.

Claim 22

In a closed cycle refrigeration system employing a compressor, condenser and receiver for supplying liquid refrigerant and multiple evaporators for multiple refrigerated fixtures wherein hot gas defrosting of such fixtures is provided, the improvement comprising, a vessel having chamber means for separating liquid and gaseous refrigerant, valve and conduit means connecting said evaporators to said vessel for selectively connecting it at least one of sad evaporators between the high pressure side of the system and said vessel to supply hot gaseous refrigerant to said evaporator for defrosting and for conducting the resultant liquid and gaseous refrigerant directly to said chamber means for separating the phases, said vessel having means in communication with the normal supply of liquid refrigerant to said evaporators for returning the liquid refrigerant resulting from defrosting into the liquid refrigerant supply for said evaporators, and means restrictively connecting said chamber means to the suction side of said compressor for controllably returning gaseous refrigerant from said chamber means to said compressor means.

Claim 23

In a closed cycle refrigeration system employing a compressor, condenser and receiver for supplying liquid refrigerant and multiple evaporators for multiple refrigerated fixtures wherein hot gas defrosting of such fixtures is provided, the improvement comprising, a vessel having chamber means for separating liquid and gaseous refrigerant, valve and conduit means connecting said evaporators to said vessel for selectively connecting it at least one of sad evaporators between the high pressure side of the system and said vessel to supply hot gaseous refrigerant to said evaporator for defrosting and for conducting the resultant liquid and gaseous refrigerant directly to said chamber means for separating the phases, said vessel having means in communication with the normal supply of liquid refrigerant to said evaporators for returning the liquid refrigerant resulting from defrosting into the liquid refrigerant supply for said evaporators, and means restrictively connecting said chamber means to the suction side of said compressor for controllably returning gaseous refrigerant from said chamber means to said compressor means.

Claim 24

The refrigeration system improvement of claim 20 wherein a regulating valve means is provided in communication with said chamber means and affirmatively produces a pressure differential between said chamber means and the supply of hot gaseous defrosting refrigerant to cause the defrosting refrigerant to flow through the evaporators to said chamber means.

Claim 25

The refrigeration system improvement of claim 20 wherein float control means are provided in said chamber means for maintaining a desired liquid level in said chamber means.

Claim 26

The refrigeration system improvement of claim 20 wherein pressure regulating valve means are provided for controlling to three predetermined pressure levels the liquid refrigerant supply, the hot gaseous defrosting refrigerant supply and the resultant refrigerant condensate returning from defrosting.

Claim 27

The refrigeration system improvement of claim 21 wherein valve and conduit means also serve to activate said regulating valve means only during the defrosting of an evaporator.

Claim 28

The refrigeration system improvement of claim 20 wherein pressure regulating valve means are provided for producing a predetermined and constant low pressure in both the normal supply of liquid refrigerant and said vessel, and the refrigerant at said constant low pressure has a saturation temperature below the normal room temperature.

Claim 29

The refrigeration system improvement of claim 20 wherein two pressure regulating valve means are provided for maintaining the pressure of said hot gaseous refrigerant within a small predetermined range under all ambient and operating conditions.