GB2122474A - Sanitizing food processors - Google Patents

Abstract

A method of sanitizing a food processing unit which carries food products through the unit on an open conveyor belt (12), comprising the steps of, pumping a warm cleaning liquid of detergent from tanks (84, 82) at a pressure of at least 100 psi (690 k Pa) to rotating spray nozzles (87, 88) positioned adjacent said conveyor belt, moving the belt past said spray nozzles to release said cleaning liquid and effectively scrub the entire belt. Warm water from tank (81) is used pre-rinse and post-rinse the belt. <IMAGE>

Description

1

SPECIFICATION

Efficient high humidityfood processing system with sanitizing improvements This invention relates to industrial food processing systems for cooking and chilling food products carried on continuously running conveyor belts and more particularly it relates to such systems which include sanitizing means operable to clean said units and belts.

Industrial cookers and chillers are known in the art which pass food products therethrough on a continuously running conveyor belt. Also sanitizing equipment and features are commonly used whenev- 80 erfood is processed. Cooking techniques which help preserve product characteristics are also known.

Examples oftypical prior arttechniques are as follows:

Conveyortype freezing and broiling apparatus in stainless steel cabinets with access doors permitting internal manual cleaning has been marketed by Certified Manufacturing, Inc. of Lynwood, California 90262.

Spiral type conveyor paths in a freezing unit 90 circulating cold dry air about a product and having associated belt sanitation equipment is disclosed in U.S. Patent 3 412 476- S. Astrorn - Nov. 26,1968.

Certain techniques resolving deficiencies in cooking and cooling food products are known in batch type 95 food processing equipmentwhere batches are placed in an oven orfreezeras long as necessaryfor processing. Thus, U.S. Patent3 597 228- M.R.

Jeppson-Aug 3,1971 introduces steam into a microwave oven to reduce loss ofwaterfrom the product and cooks in a hotoil bath to brown the product.

Similarly, U.S. Patent 2 846 318- E. J. Kelley etal.

Aug. 5,1958 introduces humidity in a low pressure freezing gas atmosphereto reduce dehumidification. 105 However, many unresolved problems remain in the prior artfood processing systems, particularly where large volumes offood are rapidly processed on a continuously running conveyor passing through cooking and chilling units.

One order ofproblems relates to energy efficiency.

In manycooking systems hot gases escape, radiation losses are large, particularly where large heated surface areas exist. In both cooking and heating systernsthere is generally an inefficiency in heat interface surfaces between the heating medium and the food product, requiring a significant expenditure ofenergywithout achieving the end result intended.

Particularly there is a lack of acceptable solutions available to the energy losses generally caused by the 120 entrance and exit of the conveyor belt from the cooking and chilling units.

Another order of problems relates to food appearance, taste and texture. It is difficuitto avoid losses of moisture and food essences in the drying atmosphere 125 of heating ovens and chillers, which both by nature tend to dehydrate a product. Thus, a meat, fish or poultry product in particular will tend to change shape and appearance as well as to lose flavour and moisture in both cooking and cooling processes. 130 GB 2 122 474 A 1 Complete uniform cooking throughout without unwanted changeto thefoodtexture has been difficuitto attain particularly when rapid processing is required in industrial type food processors.

Yetanotherset of problems comes with the requirementto processfood in a sanitary and sanitizable environment. In mostsystems a disproportionate time span and inefficiency of energyis speni intearing down a production line for sanitization.

Cooking in particular tends to burn on, dryoutand accumulate drippings, proteins and otherfood contamination resulting in unsightly and unsanitary _ equipment. Also complex equipment has surfaces and interfaces difficult to reach and in warm or protected places where bacteria can breed.

Accordingly, it is an object of this invention to provide improved food processing equipment resolving the foregoing deficiencies of the prior art.

Various techniques are known forthe processing of food products such as fish, meat, poultry or produce through cooking and cooling cycles. For example, the continuous flow of products on conveyors with elongated paths in the form of spirals orthe like through cookers or coolers is represented by the following prior art:

U.S. Patent 3 412 476- S. Astrom - Nov. 26,1968 provides a spiral conveyorthrough a freezer compartment which employs refrigerated dry air.

Certified Manufacturing, Inc. of Lynwood, California has commercially supplied continuous flowconveying systernsfor gas heated cooking and freezing of food products passed along a flow path.

U.S. Patent 3 982 481 - E.T. Console et al. - Sept. 28,1976 shows a continuous conveyortype steam heating I ine for blanching produce.

Also various cooking techniques are known in the art for treating the food products for texture, color, sanitation and flavour, as well as speed of cooking and efficiency of the treatment process. Representative art is:

U.S. Patent 3 597 228- M.R. Jeppson etal. -Aug. 3,1971 which supplements steam cooking with special microwaves and hot oil treatmentto color bones and skin in poultry and to prepare a precooking step in a chicken productwith the objective of improved flavour, coloration and sterilization resulting in a packaged product.

U.S. Patent2 846318-E.J. Kelly etaL-Aug. 5, 1958 provides low pressure water vapor in afreezerto reduce dehydration of a chilling process.

U.S. Patent4058 635-W. Durth- Nov. 15,1977 treats foodstuffs in an oven with steam orwaterspray aftercooking beginsto prevent dehydration during cooking.

U.S. Patent998236-L. Detoyet al.-July 18,1911 which has a spiral conveyorwithin a processing chamberfor processing raisins with controlsfor passing air orsteam under controlled atmospheric conditions within the chamber. In all these and other known prior art systernsthere are several deficiencies which need be corrected in an improved system.

One deficiency isthe cooking - cooling - product through-put efficiency. Various losses in the continuoustype systems are encountered not only by inefficient use of energy in various steps but also by 2 GB 2 122 474 A 2 combining in a flow process incompatible techniques which require significant losses of energy ortime at interfaces and thus significantly increase the proces sing cost per element of product, which for example may be a vegetable, a piece of meat, fish chicken, prepared meatloaf, orthe like.

Another deficiency is sanitation, since ease of cleaning, lackof accumulated productor processing ingredient waste and supervisory agency approval of food processes is critical to any processing of food products. The accumulation of dirt, bacteria, or down time forcleaning is critical.

A critical deficiency is the flavor,texture and appearance of the processed product. Not only is dehydration critical in almost any product, butflavor, 80 tenderness, colorwith uniformity underall conditions must be critically controlled. For examplethe hereinb efore described systems and techniques all fail to produce a system that produces uniformly sterile products of pleasing appearance because of specific 85 deficiencies such as uneven cooking atvarious depths particularly when products such as poultry may have a fatty insulating outside skin. Many processes produce blemishes because of drippings or non uniform product because of complex controls of many 90 variables during the process.

Another deficiency is the lack of simplicity of heat-chill methods. Where additional steps and complexities are added more difficulties are encountered in main taining product uniformity and sanitation as well as energy efficiency.

Thus it is an objective of this invention to provide improved food processing methods correcting the aforesaid deficiencies and producing an efficient and rapid cooking-cooling process that produces uniform 100 high quality and sterile processed food products.

This invention improves the state of the prior art by both cooking and chilling food products such as fish, meat, poulty and produce in an atmosphere approaching 100% humidity by use of water carried in 105 gaseous forma bout the product as it is carried on a continuously moving conveyor belt. The water is in the-form of steam for cooking and cold moist airfor chil ling to a product temperatu re approaching 0% C.

Because of this moist environment contaminating 110 residue does not tend to dry, harden or bu rn onto equipment surfaces thereby making feasible simple mechanical sanitization techniques. Also loss of moisturejuices and essencesfrom the product is prevented resulting in betterflavor. In particularthe 115 heatinterchange between the water processing medium and thefood product is efficient and reduces processing energy.

The hotcooked food product is immediately intro duced on a common conveyor belt into a chilling unit 120 to prevent any chance to come into contact with contamination orto be in a warm environment long enough to breed bacteria, as is the case in batch processing requiring transfer of the productfrom a cookerto a chiller.

Sanitary features include a continuously sanitized moving conveyor belt and an automatically cycling detergent bath system for periodic cleaning of the entirefood processing equipment at one time.

a food processing mode and a sanitation mode with the conveyor belt running continuously in both modes. There is no carry over contamination from one unitto the other as in the manual or sequential cleaning of a food processing system.

To obtain proper product dwelltime in relatively small processing unit cabinets forcooking and chilling the conveyor belt is in a spiral path giving other operational advantages such as efficient energy transfer in both cooking and chilling. This permits small insulated cooking and chilling cabinets with far less energy loss from radiation and attrition. The spiral path is cleaned in the sanitizing mode by rotary jet spray nozzles rotated within the spirals as the belt moves.

This invention further provides for the cooking and cooling in a consecutive sequence along a single. productflow line of food products such as meats, produce etc. and is particularly adapted forthe cooking of spareribs, short ribs, unskinned chicken,. poultry pieces, etc. The cooking is solely by steam in-a cooker with pressure maintained above atmospheric pressure at near 100% humidity and 99'C. The cooling is solely by circulation of cold humid air in a cooler at a pressure above atmospheric at near 100% humidity at a temperature less than 5C. The products are continuously passed along a conveyorflow line through the steamer and chiller in a completely sanitary processto befully cooked (if desired) and chilled for cold storage without dehydration at high energy efficiency, speed and volume.

Flavour andtexture is protected and heatingchilling efficiency is increased bythe humid atmosphere,which isstripped of water dropletsto prevent contamination or bad appearance.

Otherfeatures, advantages and objects of the invention will be found throughoutthe following text and the accompanying drawings, in which Figure 1 is a schematicsystern diagram of the cooker- chillersanitization system afforded by this invention; Figure 2 is an operational mode chart showing the sanitation and food processing mode control cycles operations in the system of Figure 1; and Figures 3to 6are diagrammatic views of the various parts of the system of Figure 1 shown in respective sequential'orderfrom input of a raw productto output of a cooked ' and chilled productthrough the cooker unit of Figure4 and the chiller unit of Figure 5.

Thus, the system is operated in two modes, namely 130 A 3 GB 2 122 474 A 3 As may be seen in the system view of Figure 1, a continuously running conveyor belt 12 feeds raw food products 12 loaded on the belt at an inputstation through the cooker40 and the chiller 50 to the outputstation 70 atwhich the cooked food products 12'are unloaded. The belt passesthe products at a beltspeed controlled byvariable speed drive means 14so thatthe dwell time in cooker40 on belt spiral 16 permitsthorough cooking throughoutto a tempera ture approaching 100'C if desired and similarly a chill dwell time in spiral belt path 18through the chiller 50 permitsthe hot cooked productto be chilled im mediately without chancefor contamination or bacteria growth to a temperature approaching O'C if desired.

The atmosphere in both cooker and chiller is kept near 100% humidity thereby to assure efficient thermal exchange contact between respectively hot water in theform of steam and cold water carried by cold humid air aboutthe products on the spiral belts. 85 This prevents any dehumidification of the product as well and keeps all equipment humid so that any drippings orfood residues do not burn, dry out or accu m u late, thereby facil itati ng sanitation.

The heater40, which is morefully described in my 90 co-pending U.K. patent application No. 80 24200,filed the same day asthis application, and entitled "high humidity steam cookerwith continuously running conveyor", hastwo sources of steam, namely an internal pool of water 41 heated by a heater42 and an 95 external steam generator43. The products are spiraled upwardly so that if they are fatty, such as with spare ribs, fewer drippings will drop on the cooked food products as they spiral upwardly to leavethe cooker unit40. The simple cooker unit has insulated walls and plain interior stainless steel surfacesfor ready sanitization and little tendency to form accumulated deposits of cooking residues.

The chiller5O, which is morefully described in my co-pending U.K. patent application No. 80 24218 filed the same day asthis application, and entitled "high humidity food chilling system", has refrigated water from refrigerator 51 passed by pipe 52 into atomizer sprays 53 so thatthe fan 54 can directcold moist air upwardlythrough the spiral 18 in an efficient heat exchange where cooler products on the lower part of the spiral 18 encounterthe cooler air exiting the fan 54 thus permitting efficient heat exchange atthe upper partof the spiral 18 where the hot cooked products enter. The pump 55 recirculates the cold water through refrigerator 51 to replace the energy lost in cooling the products.

By using spiral conveyor paths and the water as a heat exchange medium in the cooker40 and chiller 50, small cabinets are used for a large throughput of food products. This significantly reduces energy losses in heating up or cooling down a larger cabinet structure with attendant radiation and condensation losses over greater surface areas, and thus provides improved operating economy.

Inthe belt return path (outsidethe chillerand cooker) at leasttwo sanitizing spray bath stations 60 and 30 are positioned for respectively washing the belt with a detergent spray and rinsing with water.

The belt, which is preferably a stainess steel grating type belt is scrubbed by the spray nozzles 61,31 with a jet scrubbing action on and through the moving belt. The liquid is received in basins 62,32 and circulated by pumps 63,33 continuously whenever the belt moves. The water and detergent solution is warm in the order of 70'C and is pumped at a pressure in the order of at least 100 psi (690kPa).

Because of the high humidity in the cooker and chiller units 40, 50, residue does not collect on the belt and dry on or bake on and thus any residue from the food processing or any introduction of bacteria at unloading station 70 is easily removed bythis continuous belt cleaning and sanitizing process.

BeIttensioning means 48 is located in the return path, and as is shown in Figure 4, a further sprayjet cleaner46 station may also be located at an intermediate belt return path position for detergent wash if a water pre-rinse is preferred at cleaning station 60.

The foregoing description of the food processing mode of operation with the periodic portion of the cleaning cycles inactive is summarized in the control flow chart of Figure 2 in the Food Processing Mode Section, where the various units are placed in off or on condition by apppropriate valves, switches, servo u nits, etc.

Periodicallythe system is shut down forthe mechanical mode cleaning and sanitizing operation. This cleaning and sanitizing mode is also setforth in summarycontrol flow chartform in Figure 2 together with two auxiliary cycles namelythe pre-clean mode and the cleaning sub-cycles.

Thus mode control means 80 containsfor example a set of switches, valves orservo controls manuallyor automatically selectable to place the required items into on-off position. Forthe auxiliary cycles namely the pre-cleaning mode and the cleaning sub-cycles, timers may be used to control the sequencing, or manual controls may select each condition in a sequence manuallytimed. It is to be recognized the cleaning mode may be made completely automatic, if desired by use of an appropriate control system.

Water, such asfrom supplytank8l, is used for rinse cycles and detergent may be drawn from supplytank 82. Thefluid water and detergent solution are heated to supplythewater at about 66'C and the detergentat about70'C. Then pump 83through piping 84 supplies the stored wateror detergent as selected by valve 85 through two rotaryjoints 86to the vicinity of the respective cooker belt spiral 16 and chiller belt spiral bywayof spray nozzle rods 87,88 respectively positioned along the spiral axis.These rotatewitha jetscrubbing action byrneansof motor89to scan all sectors of the spiral in sequencewith a high pressure jet spray. The belt is moving so that the jets effectively scrub the entire belt surfaces and the cleaning ofthe interior surfaces of both cooking andchilling unitsis done simultaneously to preventcarrying residueor contamination from one to the other as might happen if sequentially cleaned.

The heate - rwater pool 41 is drained by way of valves 90,91 and warm water if clean and sanitary and withoutfat or residue in heater pool 41 may be stored in tank 81 forthe cleaning cycle. Otherwise pure water is inserted by inlet 92 and heated before 4 GB 2 122 474 A 4 use in the cleaning cycle.

With thevalve 90 open and T-valve 91 discharging water as indicated bythe flowschernatic notation 93, the cleansing bath from rotating spray nozzle pipe 87 can clean the entire inner surfaces of the cooker 40 and be discharged in an appropriate sewer line, orthe like. Pure water maythen be introduced into cooker 40 at94 and heated for a further cooking cycle.

Similarly in cooler 50, residue water 95 being circulated through refrigerator 51 is dischargeable by T-valve 96, forthe pre-clean mode only. For both clean and cook modes the water is pumped through refrigerator 51 and spray nozzles 53. New pure water may be entered at97for a new cook-chill mode of operation aftercleaning and discharge of cleaning fluids. Also T-valve 96 may send some of the rinse water back into storage tank 81 after any initial portion of the rinse water containing residues is discharged, thereby to save water and thus also energy. For sanitary purposes, any water salvage is initiated only afterthe initial detergent sediment and residue is drained off. Similarly, T-valve 91 will permit rinsewaterto be saved from cooker40. The dual line pipe notation such as at link 97 is shown for water-detergent flow paths and control mode linkages are shown by the single line notation of control I i nes 99, 100.

It is seen, by refe rence to th e co nditi o ns of Fig u re 2, that each of the valves, pumps, motors and heat exchange units can be controlled for on-off operation ordisconnected by means of controls designated along the lines 99, 100. Thus, heater42 may beturned on oroff and valves 90,91 operated along control line 99. An auxiliary pump (not shown) of course could be used to pump outthe heaterwater pool 41 and also is controlled bythis line 99.

Similarly line 100 can turn the refrigeration of unit 51 on oroff, operateT-valve 96to any of three discharge paths,turn on oroff pump 55 for circulating waterthrough the refigration-atomizer cooker circuit, choosewater8l or detergent 82 by operation of T-valve 85, operate cleaning pump 83, control belt drive at 14 if desired, rotate sprays 87,88 by means of motor 89, turn on or off the steam supplyfrom generator43, and operate fan 54.

Thuswhen in the cleaning mode detergent solution orwater rinse sprayfrom nozzles 88 in cooler 50 is accumulated in pool 95 and circulated through the refrigerator and nozzles 53. Thus atomized moisture is carried through fan filter 54to effectively clean the entire chiller 50 and also its auxiliary refrigeration system.

Preferablythe cleaning is done cyclically in three steps, namely prerinse with water, wash with detergent, and rinse with water sub-cycles, where aboutthe last half of the rinsewater is stored in tank 81 for reuse. The necessary operations are shown in the cleaning sub-cycles mode portion of Figure 2. Manual sequencing or automaticallytimed steppers can be usedfor control of these cycles while the processor is in the main cleaning mode condition. The sequencing controls utilize pump 83,T-valve 85 and storage T-valves 91,96for selection of the detergent solution and water and storage or rinse water.

Preferably during the food processing mode, cooking and chilling operations, the cooker 40 and chiller 50 are maintained at a pressure above atmospheric to reduce cooking and cooling time and improve energy efficiency. One means for supplementing the pressure isto install the cooker and cooler40,50 within a pressurized room signified by walls 21,71. This leads also to a receptiveness of the food product loaded under atmospheric pressure at station 20 to penetration of heat in cooker 40 and further retards losses of moisture and food essences from the product.

Various system features contribute in unison and cooperativelyto save energy, including such features as recirculation of beltwash waterthe direction of beittravel and the spiral pathway through the heat exchange units,the use of water as a heat exchange medium in a near 100% humidity atmosphere, the saving of cleaning fluid, the short cleaning cycle and reduced system down time, the small cabinetstructurewith attendant reduced losses,the short conveyor belt paths, etc. Other such features are also to be recognized from consideration of Figures 3 to 6.

Thus in Figure 3, the belt 12 is retained in protective ducts35 in which control means such as baffles and fans are introduced for preventing entry or exit of air carried bythe beltfrom one unitto another. Such a trap unit isshown at65 in Figure 6,wherethe ducts35 gothrough the unloading station wall 71. Thus, a fan at73 may prevent entryof cool outside air,which can dissipatethe solution spray heat atcleaning station 60, carried by belt 12 by creating a counterflowof air oppositethe belttravel and baffles may be placed in duct portion 74for reducing and retarding inward flow of air. Similartraps may be placed in the duct system at entrance- ways and exitways into the cooker 40 and cooler 50 to reduce heat losses from flowof atmosphere with the belt.

Note that a water pre-rinse maybe effected at spray cleaning station 60 in Figure 6, a detergent bath at intermediate spraycleaning station 46 in Figure 4, and a final rinse atthe typical cleaning station 30 in Figure 3, all in the conveyor belt return path between unloading station 70 and the loading station 30, thereby assuring a sanitized beltfor loading the products at station 20 under sanitary belt conditions.

In the spray station 30the sump basin 32 is arranged in the ductway about belt 12 to permitthe spray nozzle arms 36to pass the cleaning jets of warm water at a pressure produced by pump 33 in the order of 100 psi (690k Pa). Thus warm water passes through and scrubs the grid-work of the moving belt for effective rinsing. The squeeze or cleaning brush 37 cleans liquid from roller 38to prevent carrying of excess moisture along the belt path into the loading station.

It has been found that products 12 preferably of common size and shape positioned across a wide conveyor belt can pass through the system in about 20 minutes and achieve a consistent cooking temperature throughout greaterthan 90'C in the cooker and a similar consistent tern peratu re approaching O'C in the chiller, typically 5'C.

As seen inthe drawing Figure 1, food products 12', preferably of substantially the same size and weight, J v Al GB 2 122 474 A 5 are passed through a continuous flow path from loading station 20 to unloading station 70 by means of continuously running conveyor belt 12forcooking as it passesthrough steam cooker40 and chilling as it passesthrough cooker5O. The productcould be produce, meat products such as spare ribs, prepared meat cuts, poultry parts, and the like, which may be pre-cleaned and conditioned by seasoning, etc. at station 20. The processing method is particularly advantageous for cooking food products 12'which have been cleaned, cut and size atstation 20 and loaded on the conveyor belt 12, generallywith several parts 12'being positioned acrossthe width of the conveyor belt 12.

In cooking and chilling almost anyfood product it is 80 essential to get uniform cooking throughoutwith good efficiencyand without dehydration while pre serving good appearance and flavourwith a consis tent product underall conditions, and variousfea tures of this invention are provided to assurethat.

For attaining high efficiency of input energy and permitting a large throughput of products 12'in a small space, several features contribute to the system. Thus, considerthe cooking is solely by steam at a pressure above atmospheric maintained in part 90 forthe cooking and other steps of the entire process by having a module such as a building with walls 71 kept abovethe atmospheric pressure. Also the steam cooker40 is in a separate housing compartment into which the steam from generator43 is entered ata pressure above atmospheric. This gives a sort of pressure cooker efficiencyto the cooking process and enables the steam to penetrate and cookthe food productfor example since it is basically at atmospher ic pressurefrom processing at loading station 20 outsidethe increased pressure compartments.

To assure a good heat exchange interface, particu larlywith fattyfood products where thefat serves as an insulator, a fine spray mist wettens the surface for intimate and efficient interface thermal contactwith the steam in cooker40 to decrease cooking time.

Sanitation is importantthroughout as is preserva tion of flavor. Thus, pure water is provided for steam generator43 and valves providefor a flow of steam through cooker40 to exhaust at a controlled flow rate and pressure. The rate of steam flowthrough the cooker 40 is as low as feasible to maintain minimum energy losses while retaining the close to 1 OO'C ambient temperature within the cooker40 therebyto improve energy efficiency. Also, the steam produces a humidity maintained as close as possible to 100% withinthe cookerto avoid any dehydration of the product and with the pressure to avoid loss of juices from the product.

For proper cooki ng of va rious products, the con veyor 12 speed through the system may be changed and the tortious route 16 of the conveyor within the cooker 40 produces a dwell time properfor cooking the products to the extent desired. The system could be used for blanching peas, for cooking spareribs, meat slices or meatloafs, or processing otherfood products, preferably unpackaged, through a heat chill cycle.

Because a quick chill immediately after cooking is a most sanitary condition reducing possibility of intro- duction and growth of bacteria,the product is passed from the steam cooker 40 directly into the cooler 50 along theflow path defined by continuous conveyor belt 12. In the interest of energy eff iciency in the cooler 50 a heat stripper is provided to entrap and confine within the cooker 40 the hot air flowing with the product 12'and conveyor 12 out of cooker 40 before the conveyor enters cooler 50 with the heated products 12'. Thus, baff les and fans can be used, for example, in a conveyor duct between cooker40 and cooler 50 to retain hot steam in cooker 40 and prevent flow of all but a residualincrement into cooler 50 with the product 12'.

Also in the cooler 50 it is critical to maintain a pressure higherthan atmospheric and near 100% humidityto keepthe productfrom dehydrating and losing juices or flavor as itis passed along tortious path 16 providing a dwell time long enough to bring the product temperature at cooking heat near99'C, forexample, down to nearOOC.

This is achieved by circulating saturated 100% humidity airwithout droplets through the cooler 50 by means of fan 54which keepsthe cooler internal pressure above atmospheric. The air leaving the cooler is keptcold and humid by a cold waterspray 53 which uses uncontaminated water. Afilter 54strips water droplets before circulation into cooler5O so there can be no dripping to assure best appearance and sanitation conditions. Thus, the belt 12 and products 12'thereon remain substantially free of residual drippings or accumulation of product orwater drop contamination and the belt 12 is readily sanitized at stations 60 and 30 before re-entry into a repeat cyclethrough the heat-chill process. The conveyor is returned outside the cooking and cooling chambersto prevent any baked on contamination or the like. The high humidty contributes to the easy removability of any drippings or product residue in the conveyor sanitizer station which might simply be a spray detergent bath.

It is therefore evident that various novel features including a mechanically operated sanitizing system and efficient cooking and chilling means are provided bythis invention. Those novel features believed descriptive of the spirit and nature of the invention are defined with particularly in the claims.

In summary therefore, the invention is an industrial food processing system rapidly cooks and chills food products carried between a loading station and unloading station by a continuously moving conveyor belt. The system operates in both food processing and automatic sanitization modes. It processes food through both heating and chilling cycles with high energy efficiency and without dehumclification

Claims (7)

in a sanitary environment. CLAIMS

1. The method of sanitizing a food processing system changing food temperature in at least one food processing unit by carrying food products through the unit on a conveyor belt having grating aperture structure therethrough, comprising the steps of, pumping a warm cleaning liquid at a pressure in the order of at least 100 psi (690k Pa) to a spray nozzle set positioned adjacent said conveyor belt, 6 GB 2 122 474 A 6 moving the belt past said spray nozzle set, and directing said spray nozzle setto release said detergent in a jet cleaning action againstthe moving belt.

2. The method defined in claim I with the additional steps of moving the belt continuously, and pumping the detergent continuously through said spray nozzle setto pass through said belt.

3. The method defined in claim 1 wherein the belt is directed along a spiral pathwaythrough the food processing unit, including the steps of rotating the spray nozzle setwithin the spiral pathway to scan the jet cleaning action in a cyclic rotary path contacting the beitthroughout its sprial path.

4. The method defined in claim 1 wherein the pumped cleaning liquid is water.

5. The method defined in claim 1 including the step of saving, storing and reusing a portion of the water sprayed through said nozzle set.

6. The method defined in claim 1 wherein the pumping step includes the sequential pumping of a water pre-rinse, a detergent washing solution and a water rinsethrough said pumping step.

7. A method of sanitizing a food processing system substantially as hereinbefore described with reference to the accompanying drawings.

Printed for Her Majesty's Stationery Office byTheTweeddale Press Ltd., Berwick-upon-Tweed, 1984. Published atthe PatentOffice, 25 Southampton Buildings, London WC2A lAY,from which copies may be obtained.

A 7 A 4 S i- J

7. The method defined in claim 1 wherein the pumped cleaning liquid is a detergent solution.

8. The method defined in claim 1 wherein the sanitizing steps are periodically undertaken whilethe food processing unit is shutdown.

9. A method of sanitizing a food processing system substantially as hereinbefore described with reference to the accompanying drawings. New or amended claims 1. A method of sanitizing a food processing system changing food temperature in at least one food processing unit by carrying food products through the unit on a conveyor belt directed along a spiral pathway and having a grating aperture structure therethrough, comprising the steps of pumping a warm cleaning liquid at a pressure in the order of at least 100 psi (690 kpa) to a rotatable spray nozzle set adjacenttothe conveyor belt and within said spiral pathwayto produce a jet cleaning action, moving the belt pastsaid spray nozzle set, rotating the spray nozzle setwithin the spiral pathwayto scan all sectors of the spiral with the jet cleaning action.

2. A method as claimed in claim 1 wherein the pumped cleaning liquid water.

3. A method as claimed in claim 2 including the step of saving, storing and reusing a portion of the watersprayed through said nozzle set.

4. A method as claimed in claim 1 wherein the pumping step includes the sequential pumping of a water pre-rinse, a detergent solution and a water rinse.

5. A method as claimed in claim 1 wherein the pumped cleaning liquid is a detergent solution.

6. Amethod asclaimed in claim 1 where inthe sanitizing steps are periodically undertaken while the food processing unit is shutdown.