# US 5,343,715 A · Helical conveyor freezer

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- Number: US 5,343,715 A
- Document ID: US5343715A
- Status: Granted
- Kind: A
- Application number: 08/012,008
- Filed: 1993-02-01
- Granted: 1994-09-06
- Earliest claimed: 1991-11-13
- Assignees: Liquid Carbonic Corporation
- Inventors: Gary D. Lang
- Web page: https://patentgrep.com/patent/US5343715A

## CPC

- A23B 2/803: {Materials being transported through or in the apparatus, with or without shaping, e.g. in the form of powders, granules or flakes}
- A23B 2/88: with direct contact between the food and the chemical, e.g. liquid N2 at cryogenic temperature
- F25D 3/11: with conveyors carrying articles to be cooled through the cooling space
- F25D 13/067: {with circulation of gaseous cooling fluid}
- F25D 16/00: Devices using a combination of a cooling mode associated with refrigerating machinery with a cooling mode not associated with refrigerating machinery
- B65G 2207/24: Helical or spiral conveying path
- A23B: PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
- F25D: REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR (refrigerated showcases A47F3/04; thermally-insulated vessels for domestic use A47J41/00; refrigerated vehicles, see the appropriate subclasses of classes B60 - B64; containers with thermal insulation in general B65D81/38; heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants, or materials for the production of heat or cold by chemical reactions other than by combustion C09K5/00; thermally-insulated vessels for liquefied or solidified gases F17C; air-conditioning or air-humidification F24F; refrigeration machines, plants, or systems F25B; cooling of instruments or comparable apparatus without refrigeration G12B)
- B65G: TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS (packaging B65B; handling thin or filamentary materials, e.g. paper sheets or thread, B65H; cranes B66C; portable mobile or lifting or hauling appliances, e.g. hoists, B66D; devices for lifting or lowering goods for loading or unloading purposes, e.g. fork-lift trucks, B66F9/00; emptying bottles, jars, casks, barrels or similar containers, not otherwise provided for, B67C9/00; delivering or transferring liquids B67D; filling or discharging vessels for liquefied, solidified or compressed gases F17C; pipe-line systems for fluids F17D)

## Abstract

A food freezer for continuous freezing of food products utilizing a helical conveyor for transporting the food products through an enclosure in which the food products are cooled. Mechanical refrigeration apparatus employs a refrigerant to cool an atmosphere gas which is circulated across the food products within the enclosure. The refrigerant is also employed to subcool a cryogen which also cools the same food products.

## Claims

### Claim 1

A combination food freezer having mechanical and cryogenic cooling apparatus comprising:
a source of cryogen;
an insulated enclosure including a conveyor for conveying food products through said enclosure;
refrigeration apparatus including a first heat exchanger receiving mechanically cooled refrigerant, said refrigerant having a composition different from said cryogen, and disposed within said enclosure and gas circulation means to circulate an atmosphere gas through said first heat exchanger and across said food products to cool said food products;
said refrigeration apparatus including mechanical refrigeration connected to said first heat exchanger to circulate a mechanically-cooled refrigerant through said first heat exchanger, said refrigeration apparatus further including cryogenic cooling apparatus coupled to said source of cryogen and having means within said enclosure for spraying said cryogen across the food products on said conveyor; and
a second heat exchanger connected between said mechanical refrigeration and said first heat exchanger, so as to receive said mechanically-cooled refrigerant and said second heat exchanger coupled to said source of cryogen to subcool said cryogen with the mechanically-cooled refrigerant prior to spraying said cryogen across said food products and prior to circulating the mechanically-cooled refrigerant through said first exchanger.

### Claim 2 (depends on 1)

A combination food freezer as recited in claim 1 wherein said cryogenic cooling apparatus includes a source of cryogen and conduit means connecting said source to said means for spraying cryogen, said second heat exchanger being a shell and tube heat exchanger having a continuous tube disposed in a housing, said mechanical refrigeration being circulated through said continuous tube in said second heat exchanger and said conduit means connecting said cryogen from said source through said housing whereby said mechanical refrigerant further cools said cryogen.

### Claim 3 (depends on 1)

A combination food freezer as recited in claim 1 wherein said atmosphere gas within said enclosure is cooled by said first heat exchanger and by said cryogenic cooling apparatus, and control means to vary the proportion of mechanical refrigeration cooling to cryogenic cooling.