# US 5,349,828 A · Conveyor belt cleaning apparatus for food freezing

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- Number: US 5,349,828 A
- Document ID: US5349828A
- Status: Granted
- Kind: A
- Application number: 08/122,676
- Filed: 1993-09-17
- Granted: 1994-09-27
- Earliest claimed: 1993-09-17
- Assignees: The BOC Group, Inc.
- Inventors: Ron C. Lee; Mark J. Kirschner
- Web page: https://patentgrep.com/patent/US5349828A

## CPC

- F25D 3/11: with conveyors carrying articles to be cooled through the cooling space
- 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
- B65G 45/22: comprising fluid applying means
- F25D 2317/0661: from the bottom
- F25D 2400/22: Cleaning means for refrigerating devices
- 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)
- A23B: PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
- 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 freezer having a freezing compartment and a porous conveyor belt for conveying articles through the freezing compartment. A vaporizer is provided to vaporize a stream of liquid cryogen. Vaporized cryogen is directed against the belt as a plurality of jets to blow accumulated ice off the belt. The vaporizer is located within the freezing compartment so that the cooling potential of the cryogen is not wasted and the vaporizer can serve as a preferential condensation site for the moisture.

## Claims

### Claim 1

In a freezer comprising: a freezing compartment having an inlet through which articles to be refrigerated enter the freezing compartment, the refrigeration supplied by a liquid cryogen and the articles refrigerated at a temperature higher than that of the liquid cryogen prior to entry of the liquid cryogen to the freezing compartment and an outlet through which the articles are discharged from the freezing compartment after having been refrigerated; and a porous conveyor belt for conveying the articles through the freezing compartment, from the inlet to the outlet, the porous conveyor belt accumulating ice during operation of the freezer; the improvement comprising:
liquid cryogen conduit means configured to be connected to a source of the liquid cryogen for conveying a stream of the liquid cryogen into the freezing chamber;
a vaporizer located within the freezing chamber and in communication with the liquid cryogen conduit means for vaporizing the stream of the liquid cryogen to form cryogenic vapor while said freezer is in use; and
means for forming and for directing jets of the cryogenic vapor against the porous belt to clear ice accumulated on the porous belt.

### Claim 2 (depends on 1)

The improvement of claim 1 in which the vaporizer comprises finned vaporizer tubing.

### Claim 3 (depends on 1)

The improvement of claim 1 in which the jet directing means comprises a header pipe connected to the vaporizer and blow-off nozzles connected to the header pipe so as to underlie the porous conveyor belt.

### Claim 4 (depends on 1)

The improvement of claim 1, wherein: the freezer is a fluidized bed freezer; the cryogen comprises nitrogen; the freezer has liquid nitrogen introduction means located within the freeing compartment for introducing liquid nitrogen into the freezing compartment to refrigerate the articles, the liquid cryogen conduit means comprises a branched conduit having a primary branch connected to the liquid nitrogen introduction means and a subsidiary branch connected to the vaporizer; and the jet forming and directing means is located beneath the conveyor belt.

### Claim 5 (depends on 4)

The improvement of claim 4 in which the vaporizer comprises finned vaporizer tubing.

### Claim 6 (depends on 5)

The improvement of claim 5 in which the jet directing means comprises a header pipe connected to the vaporizer and blow-off nozzles connected to the header.