GB2056842A - Efficient high humidity food processing system with sanitizing improvements - Google Patents

Abstract

A food processing system for heating and chilling of food products comprises a continuously running conveyor belt passing through food load and unloading stations and intermediate food heating and cooling chambers, there being spiral conveyor belt paths for carrying food products from the loading station to the heating chamber and from the chilling chamber to the unloading station, the system additionally comprising continuously operable belt cleaning and sanitizing means which are positioned in the belt return path from the unloading station to the loading stations. Also described is a food processing system including means for altering the temperature of food products passed through a food processing unit and also means for sanitizing the unit which pump a detergent cleaning solution through a rotating spray into the unit to reach all interior surfaces of the food processing unit. Also described is a method of sanitizing a food processing system with a conveyor belt having a grating aperture structure by pumping a warm cleaning liquid at a pressure of at least 100 psi (690k Pa) to a spray nozzle set positioned adjacent the conveyor belt so that detergent is released in a jet cleaning action against the moving belt. The specification also describes a process of preparing food products in which the products are quickly heated and cooled between input and output stations to ensure low bacteria count by heating the products solely by steam in an atmosphere of 100% humidity, and cooling the heated products to a temperature of less than 5 DEG C in an atmosphere of chilled moist air of 100% humidity.

Description

SPECIFICATION Efficient high humidity food 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 whenever food is processed.

Cooking techniques which help preserve product characteristics are also known.

Examples of typical prior art techniques are as follows: Conveyor type 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 circulating cold dry air about a produclt and having associated belt sanitation equipment is disclosed in U.S. Patent 3412476-S. As trom-Nov. 26, 1968.

Certain techniques resolving deficiencies in cooking and cooling food products are known in batch type food processing equipment where batches are placed in an oven or freezer as long as necessary for processing.

Thus, U.S. Patent 3597228-M. R.

Jeppson -Aug. 3, 1971 introduces steam into a microwave oven to reduce loss of water from the product and cooks in a hot oil bath to brown the product.

Similarly, U.S. Patent 2846318-E. J.

Kelley et al.--Aug. 5, 1958 introduces humidity in a low pressure freezing gas atmosphere to reduce dehumidification.

However, many unresolved problems remain in the prior art food processing systems, particularly where large volumes of food are rapidly processed on a continuously running conveyor passing through cooking and chilling units.

One order of problems related to energy efficiency. In many cooking systems hot gases escape, radiation losses are large, particularly where large heated surface areas exist. In both cooking and heating systems there is generally an inefficiency in heat interface surfaces between the heating medium and the food product, requiring a significant expenditure of energy without achieving the end result intended. Particularly there is a lack of acceptable solutions available to the energy losses generally caused by the 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 difficult to avoid losses of moisture and food essences in the drying atmosphere 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 iose flavor and moisture in both cooking and cooling processes. Complete uniform cooking throughout without unwanted change to the food texture has been difficult to attain particularly when rapid processing is required in industrial type food processors.

Yet another set of problems comes with the requirement to process food in a sanitary and sanitizable environment. In most systems a disproportionate time span and inefficiency of energy is spent in tearing down a production line for sanitization. Cooking in particular tends to turn on, dry out and accumulate drippings, proteins and other food 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 for the 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 or the like through cookers or coolers is represented by the fol iowing prior art: U.S. Patent 3412476-S. Astrom-Nov.

26, 1 968 provides a spiral conveyor through a freezer compartment which employs refrigerated dry air.

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

U.S. Patent 3982481-E. T. Console et al.-Sept. 28, 1 976 shows a continuous conveyor type steam heating line for blanching produce.

Also various cooking techniques are known in the art for treating the food products for texture, color, sanitation and flavor, as well as speed of cooking and efficiency of the treatment process. Representative art is: U.S. Patent 3597228-M. R. Jeppson et al.--Aug. 3, 1971 which supplements steam cooking with special microwaves and hot oil treatment to color bones and skin in poultry and to prepare a precooking step in a chicken product with the objective of improved flavor, coloration and sterilization resulting in a packaged product.

U.S. Patent 2846318-E. J. Kelly et al-Aug, 5, 1 958 provides low pressure water vapor in a freezer to reduce dehydration of a chilling process.

U.S. Patent 4 058 35-W. Durth-Nov.

15, 1 977 treats foodstuffs in an oven with steam or water spray after cooking begins to prevent dehydration during cooking.

U.S. Patent 998236-L. Detoy et al.- July 18, 1 911 which has a spiral conveyor within a processing chamber for processing raisins with controls for passing air or steam under controlled atmospheric conditions within the chamber. In all these and other known prior art systems there are several deficiencies which need be corrected in an improved system.

One deficiency is the cooking-cooling-product throughput efficiency. Various losses in the continuous type systems are encountered not only by inefficient use of energy in various steps but also by combining in a flow process incompatible techiques which require significant losses of energy or time at interfaces and thus significantly increase the processing cost per element of product, which for example may be a vegetable, a piece of meat, fish chicken, prepared meatloaf, or the like.

Another deficiency is sanitation, since ease of cleaning, lack of accumulated product or 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 for cleaning is critical.

A critical deficiency is the flavor, texture and appearance of the processed product. Not only is dehydration critical is almost any product, but flavor, tenderness, color with uniformity under all conditions must be critically controlled. For example the herein before described systems and techniques all fail to produce a system that produces uniformly sterile products of pleasing appearance because of specific deficiencies such as uneven cooking at various depths particularly when products such as poultry may have a fatty insulating outside skin. Many processes produce blemishes because of drippings or nonuniform product because of complex controls of many 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 maintaining 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 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, poultry and produce in an atmosphere approaching 100% humidity by use of water carried in gaseous form about 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 air for chilling to a product temperature approaching 0 C. Because of this moist environment contaminating residue does not tend to dry, harden or burn onto equipment surfaces thereby making feasible simple mechanical sanitization techniques. Also loss of moisture juices and essences from the product is prevented resulting in better flavor. In particular the heat interchange between the water processing medium and the food product is efficient and reduces processing energy.

The hot cooked food product is immediately introduced on a common conveyor belt into a chilling unit to prevent any chance to come into contact with contamination or to be in a warm environment long enough to breed bacteria, as is the case in batch processing requiring transfer of the product from a cooker to a chiller.

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

Thus, the system is operated in two modes, namely 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 unit to the other as in the manual or sequential cleaning of a food processing system.

To obtain proper product dwell time in relatively small processing unit cabinets for cooking 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 product flow line of food products such as meats, produce, etc., and is particularly adapted for the 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 5"C. The products are continuously passed along a conveyor flow line through the steamer and chiller in a completely sanitary process to be fully cooked (if desired) and chilled for cold storage without dehydration at high energy efficiency, speed and volume.

Flavor and texture is protected and heatingchilling efficiency is increased by the humid atmosphere, which is stripped of water droplets to prevent contamination or bad appearance.

Other features, advantages and objects of the invention will be found throughout the following text and the accompanying drawings, in which Figure 1 is a schematic diagram of the cooker-chiller-sanitization 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 Fig.

1; and Figures 3 to 6 are diagrammatic views of the various parts of the system of Fig. 1 shown in respective sequential order from input of a raw product to output of a cooked and chilled product through the cooker unit of Fig. 4 and the chiller unit of Fig. 5.

As may be seen in the system view of Fig.

1, a continuously running conveyor belt 1 2 feeds raw food products 1 2 loaded on the belt at an input station 20 through the cooker 40 and the chiller 50 to the output station 70 at which the cooked food products 1 2' are unloaded. The belt passes the products at a belt speed controlled by variable speed drive means 14 so that the dwell time in cooker 40 on belt spiral 1 6 permits thorough cooking throughout to a temperature approaching 100"C if desired and similarly a chill dwell time on spiral belt path 1 8 through the chiller 50 permits the hot cooked product to be chilled immediately without chance for contamination or bacteria growth to a temperature approaching 0 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 the form of steam and cold water carried by cold humid air about the products on the spiral belts. This prevents any dehumidification of the product as well and keeps all equipment humid so that any drippings or food residues do not burn, dry out or accumulate, thereby facilitating sanitation.

The heater 40, which is more fully described in my co-pending U.K. patent application No. , filed the same day as this application, and entitled "high humidity steam cooker with continuously running conveyor", has two sources of steam, namely an internal pool of water 41 heated by a heater 42 and an external steam generator 43. 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 leave the cooker unit 40. The simple cooker unit has insulated walls and plain interior stainless steel surfaces for ready sanitization and little tendency to form accumulated deposits of cooking residues.

The chiller 50, which is more fully described in my co-pending U.K. patent application No. filed the same day as this application, and entitled "high humidity food chilling system", has refrigerated water from refrigerator 51 passed by pipe 52 into atomizer sprays 53 so that the fan 54 can direct cold moist air upwardly through the spiral 1 8 in an efficient heat exchange where cooler products on the lower part of the spiral 18 encounter the cooler air exiting the fan 54 thus permitting efficient heat exchange at the upper part of the spiral 1 8 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 cooker 40 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.

In the belt return path (outside the chiller and cooker) at least two 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 stainless 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 by this continuous belt cleaning and sanitizing process.

Belt tensioning means 48 is located in the return path, and as is shown in Fig. 4, a further spray jet cleaner 46 station may also be located at an intermediate belt return path position for detergent wash if a water prerinse 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 Fig. 2 in the Food Processing Mode Section, where the various units are placed in off or on condition by appropriate valves, switches, servo units, etc.

Periodically the system is shut down for the mechanical mode cleaning and sanitizing operation. This cleaning and sanitizing mode is also set forth in summary control flow chart form in Fig. 2 together with two auxiliary cycles namely the pre-clean mode and the cleaning sub-cycles.

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

Water, such as from supply tank 81, is used for rinse cycles and detergent may be drawn from supply tank 82. The fluid water and detergent solution are heated to supply the water at about 66"C and the detergent at about 70"C. Then pump 83 through piping 84 supplies the stored water or detergent as selected by valve 85 through two rotary joints 86 to the vicinity of the respective cooker belt spiral 1 6 and chiller belt spiral by way of spray nozzle rods 87, 88 respectively positioned along the spiral axis. These rotate with a jet scrubbing action by means of motor 89 to scan all sectors of the spiral in sequence with a high pressure jet spray.The belt is moving so that the jets effectively scrub the entire belt surfaces and the cleaning of the interior surfaces of both cooking and chilling units is done simultaneously to prevent carrying residue or contamination from one to the other as might happen if sequentially cleaned.

The heater water pool 41 is drained by way of valves 90, 91 and warm water if clean and sanitary and without fat or residue in heater pool 41 may be stored in tank 81 for the cleaning cycle. Otherwise pure water is inserted by inlet 92 and heated before use in the cleaning cycle.

With the valve 90 open and T-valve 91 discharging water as indicated by the flow schematic notation 93, the cleaning 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, or the like. Pure water may then be introduced into cooker 40 at 94 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, for the 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 at 97 for a new cook-chill mode of operation after cleaning 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 after the initial detergent sediment and residue is drained off. Similarly T-valve 91 will permit rinse water to be saved from cooker 40.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 lines 99, 100.

it is seen, by reference to the conditions of Fig. 2, that each of the valves, pumps, motors and heat exchange units can be controlled for on-off operation or disconnected by means of controls designated along the lines 99, 100.

Thus, heater 42 may be turned on or off and valves 90, 91 operated along control line 99.

An auxiliary pump (not shown) of course could be used to pump out the heater water pool 41 and also is controlled by this line 99.

Similarly line 1 00 can turn the refrigeration of unit 51 on or off, operate T-valve 96 to any of three discharge paths, turn on or off pump 55 for circulating water through the refrigeration-atomizer cooker circuit, choose water 81 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 supply from generator 43, and operate fan 54.

Thus when in the cleaning mode detergent solution or water rinse spray from 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 54 to effectively clean the entire chiller 50 and also its auxiliary refrigeration system.

Preferably the cleaning is done cyclically in three steps, namely pre-rinse with water, wash with detergent, and rinse with water subcycles, where about the last half of the rinse water is stored in tank 81 for reuse. The necessary operations are shown in the cleaning sub-cycles mode portion of Fig. 2. Manual sequencing or automatically timed steppers can be used for 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, 96 for selection of the detergent solution and water and storage of 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 is to install the cooker and cooler 40, 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 cooperatively to save energy, including such features as recirculation of belt wash water, the direction of belt travel 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 cabinet structure with attendant reduced losses, the short conveyor belt paths, etc. Other such features are also to be recognized from consideration of Figs. 3 to 6.

Thus in Fig. 3, the belt 1 2 is retained in protective ducts 35 in which control means such as baffles and fans are introduced for preventing entry of exit of air carried by the belt from one unit to another. Such a trap unit is shown at 65 in Fig. 6, where the ducts 35 go through the unloading station wall 71.

Thus, a fan at 73 may prevent entry of cool outside air, which can dissipate the solution spray heat at cleaning station 60, carried by belt 1 2 by creating a counter flow of air opposite the belt travel and baffles may be placed in duct portion 74 for reducing and retarding inward flow of air. Similar traps may be placed in the duct system at entranceways and exitways into the cooker 40 and cooler 50 to reduce heat losses from flow of atmosphere with the belt.

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

In the spray station 30 the sump basin 32 is arranged in the ductway about belt 1 2 to permit the spray nozzle arms 36 to pass the cleaning jets of warm water at a pressure produced by pump 33 in the order of 100 psi (690 kPa). Thus warm water passes through and scrubs the gridwork of the moving belt for effective rinsing. The squeeze or cleaning brush 37 cleans liquid from roller 38 to prevent carrying of excess moisture along the belt path into the loading station.

It has been found that products 1 2 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 greater than 90"C in the cooker and a similar consistent temperature approaching 0 C in the chiller, typically 5"C.

As seen in the drawing Fig. 1, food products 12', preferably of substantially the same size and weight, are passed through a continuous flow path from loading station 20 to unloading station 70 by means of continuously running conveyor belt 1 2 for cooking as it passes through steam cooker 40 and chilling as it passes through cooker 50. The product could be produce, meat products such as spareribs, 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 sized at station 20 and loaded on the conveyor belt 12, generally with several parts 12' being positioned across the width of the conveyor belt 12.

In cooking and chilling almost any food product it is essential to get uniform cooking throughout with good efficiency and without dehydration while preserving good appearance and flavor with a consistent product under all conditions, and various features of this invention are provided to assure that.

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, consider the cooking is solely by steam at a pressure above atmospheric maintained in part for the cooking and other steps of the entire process by having a module such as a building with walls 71 kept above atmospheric pressure. Also the steam cooker 40 is in a separate housing compartment into which the steam from generator 43 is entered at a pressure above atmospheric.

This gives a sort of pressure cooker efficiency to the cooking process and enables the steam to penetrate and cook the food product for example since it is basically at atmospheric pressure from processing at loading station 20 outside the increased pressure compartments.

To assure a good heat exchange interface, particularly with fatty food products where the fat serves as an insulator, a fine spray mist wettens the surface for intimate and efficient interface thermal contact with the steam in cooker 40 to decrease cooking time.

Sanitation is important throughout as is preservation of flavor. Thus, pure water is provided for steam generator 43 and valves provide for a flow of steam through cooker 40 to exhaust at a controlled flow rate and pressure. The rate of steam flow cooker 40 is as low as feasible to maintain minimum energy losses while retaining the close to 1 00 C ambient temperature within the cooker 40 thereby to improve energy efficiency. Also, the steam produces a humidity maintained as close as possible to 100% within the cooker to avoid any dehydration of the product and with the pressure to avoid loss of juices from the product.

For proper cooking of various products, the conveyor 1 2 speed through the system may be changed and the tortious route 1 6 of the conveyor within the cooker 40 produces a dwell time proper for cooking the products to the extent desired. The system could be used for blanching peas, for cooking spareribs, meat slices or meatloafs, or processing other food products, preferably unpackaged.

through a heat-chill cycle.

Because a quick chill immediately after cooking is a most sanitary condition reducing possibility of introduction and growth of bacteria, the product is passed from the steam cooker 40 directly into the cooler 50 along the flow path defined by continuous conveyor belt 1 2. In the interest of energy efficiency in the cooler 50 a heat stripper is provided to entrap and confine within the cooker 40 the hot air flowing with the product 1 2' and conveyor 1 2 out of cooker 40 before the conveyor enters cooler 50 with the heated products 12'. Thus, baffles and fans can be used, for example, in a conveyor duct between cooker 40 and cooler 50 to retain hot steam in cooker 40 and prevent flow of all but a residual increment into cooler 50 with the product 1 2'.

Also in the cooler 50 it is critical to maintain a pressure higher than atmospheric and near 100% humidity to keep the product from dehydrating and losing juices or flavor as it is passed along tortious path 1 6 providing a dwell time long enough to bring the product temperature at cooking heat near 99 C, for example, down to near 0 C.

This is achieved by circulating saturated 1 00% humidity air without droplets through the cooler 50 by means of fan 54 which keeps the cooler internal pressure above atmospheric. The air leaving the cooler is kept cold and humid by a cold water spray 53 which uses uncontaminated water. A filter 54 strips water droplets before circulation into cooler 50 so there can be no dripping to assure best appearance and sanitation conditions. Thus, the belt 1 2 and products 121 thereon remain substantially free of residual drippings or accumulation of product or water drop contamination and the belt 1 2 is readily sanitized at stations 60 and 30 before re-entry into a repeat cycle through the heat-chill process.

The conveyot is returned outside the cooking and cooling chambers to prevent any baked on contamination or the like. The high humid ity 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 by this invention.

Those novel features believed descriptive of the spirit and nature of the invention are defined with particularity in the claims.

In summary therefore, the invention is an industrial food processing system rapidly cooks and chills food products carried be tween a loading station and unloading station by a continuously moving conveyor belt. The system operates in both foods processing and automatic sanitization modes. Bt processes food through both heating and chilling cycles with high energy efficiency and without de humidification in a sanitary e.lvironment.

Claims (49)

1. A food processing system for heating and chilling food products such as fish, meat, poultry and produce passing in sequence on a common conveyor belt through heating and chilling stations, comprising in combination, a continuously running conveyor belt pass ing through food loading and unloading sta tions, a heating chamber having a spiral conveyor belt path therethrough for carrying food prod ucts loaded at said loading station, a chilling chamber having a spiral conveyor belt path therathrnugh for carrying food prod ucts on said belt heated in said heating cham ber to present chilled food products at said unloading station, and continuously operable belt cleaning and sanitizing means positioned in the belt return path from said unloading station to said load ing station.

2. A system as defined in claim 1 wherein said heating chamber comprises means heat ing said products solely in a steam bath at a temperature approaching 1 00 C and a humid ity approaching 100%.

3. The system defined in claim 2 having means establishing a pressure within said heating chamber above atmospheric.

4. The system as defined in claim 2 with two sources of steam comprising respectively steam generated externally of said chamber and piped thereinto and a heated pool of water within said heating chamber.

5. A system as defined in claim 2 having a heating chamber spiral conveyor belt path of predetermined length and means controlling the conveyor speed to produce a product temperature in the order of 90 C throughout when conveyed by the conveyor belt out of the heating chamber into said chilling cham ber.

6. A system as defined in claim 1 wherein said chilling chamber comprises means chilling said products solely by flowing cold satu rated air approaching 0 C, 100% humidity and a pressure equal to or higher than atmo spheric about the products.

7. A system as defined in claim 6 includ ing means deriving said flowing air by spray ing refrigerated water within the chilling chamber and circulating air within the chilling chamber through the refrigerated water spray and into contact with food products on said spiral conveyor path.

8. A system as defined in claim 6 having a chilling chamber conveyor belt spiral path of predetermined length and means controlling the conveyor speed to produce a product temperature in the order of 5"C in a product entering the chilling chamber at a temperature in the order of 90"C.

9. A system as defined in claim 1 wherein said belt cleaning means comprises a continuously running spray disposing a detergent solution on said belt.

10. A system as defined in claim 1 including a mechanically operable sanitizing system for said heating and chilling chambers including means for pumping and spraying detergent solutions inside the chambers over the spiral pathway of the conveyor belt therethrough.

11. A system as defined in claim 10 wherein the mechanically operable sanitizing system includes rotatable spray nozzle means extending within the spiral belt paths respectively inside the heating and chilling chambers to rotate and scan the spray about the insides of the chambers, and means operating both the rotatable spray means in a cleaning mode simultaneously.

12. A system as defined in claim 10 including means operating the mechanical sanitizing system while the conveyor belt is continuously running.

1 3. A system as defined in claim 10 wherein the chilling chamber has chilling means circulating cold water through spray atomizer means and a fan circulating cold humid air from the spray region to contact food products on said spiral conveyor belt path, and the mechanical sanitizing system is operated together with the chilling chamber means for circulating water and air, thereby to pass sanitizing solution through the chilling means for the chilling chamber.

14. A food processing system with a food processing unit therein having a conveyor belt carrying food products therethrough with means operating the processing unit in two modes, namely a food processing mode and a sanitation mode, means altering the temperature of food products passed through the food processing unit on said belt in the food processing mode, and sanitation means pumping a detergent cleaning solution into said food processing unit through a rotating spray directing detergent to reach all interior surfaces of the food processing unit in the sanitation mode.

1 5. A food processing system as defined in claim 14 having two said food processing units, one for heating food and the other for chilling foods with the conveyor belt passing in sequence through spiral paths in each unit, wherein said rotary spray means is located in each unit, and including means pumping the detergent through both rotating spray means simultaneously.

16. A food processing system as defined in claim 1 5 including means operable with said heating unit establishing a water pool therein for steaming products passing through the heating unit on said belt, means removing said water from the heating unit, and means thereafter processing detergent from said spray over the entire inner surface of the heating unit.

1 7. A food processing system as defined in claim 1 5 including cooling means with a pump operable with said chilling unit for circulating refrigerated water through atomizing sprays and circulating air by fan means through the atomizing sprays, including means removing water from said cooling means and passing detergent therethrough when detergent is pumped through the rotating spray means in said chiller unit to thereby clean the entire interior surfaces of the chiller unit and those in the cooling means.

18. A system as defined in claim 14 wherein said sanitation means includes control means for sequencing a water rinse cycle, a detergent wash cycle and a water rinse cycle through said rotating spray.

1 9. A system as defined in claim 14 wherein said sanitation means includes means creating a spray jet discharging solution at a pressure in the order of 150 psi (0133.5k Pa).

20. A system as defined in claim 14 wherein said detergent cleaning solution is heated to a temperature in the order of 70"C.

21. A system as defined in claim 14 including sanitizing means continuously cleaning the running conveyor belt with a detergent spray solution at a pressure in the order of at least 100 psi (690k Pa) flowing from spray nozzles against said belt.

22. A system as defined in claim 14 wherein the food processing unit is a heater in a housing, and spiral conveyor path passes upwardly therethrough to reduce drippings downwardly through said spiral path as fatty products are heated.

23. A system as defined in claim 14 wherein the food processing unit is a chiller in a housing, a spiral conveyor path goes downwardly through said housing and a fan passes cooling air upwardly through said spiral path to thereby effectuate an efficient cooling at all product temperature gradients along the spiral path.

24. A system as defined in claim 1 4 with means continuously running the conveyor belt in both modes through the food processing unit.

25. 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, moving the belt past said spray nozzle set, and directing said spray nozzle set to release said detergent in a jet cleaning action against the moving belt.

26. The method defined in claim 25 with the additional steps of moving the belt continuously, and pumping the detergent continuously through said spray nozzle set to pass through said belt.

27. The method defined in claim 25 wherein the belt is directed along a spiral pathway through the food processing unit, including the steps of rotating the spray nozzle set within the spiral pathway to scan the jet cleaning action in a cyclic rotary path contacting the belt throughout its spiral path.

28. The method defined in claim 25 wherein the pumped cleaning liquid is water.

29. The method defined in claim 28 including the step of saving, storing and reusing a portion of the water sprayed through said nozzle set.

30. The method defined in claim 25 wherein the pumping step includes the sequential pumping of a water pre-rinse, a detergent washing solution and a water rinse through said pumping step.

31. The method defined in claim 25 wherein the pumped cleaning liquid is a detergent solution.

32. The method defined in claim 25 wherein the sanitizing steps are periodically undertaken while the food processing unit is shut down.

33. The process of preparing food products by passing in a continuous flow path between an input and output station the food products, to heat and quick cool the product for preservation with low bacteria count, comprising the following ordered steps, (a) heating the products in the flow path solely by steam in an atmosphere of the order of 100% humidity, and (b) cooling the heated products in the flow path to a temperature in the order of less than 5"C in an atmosphere of chilled moist air of the order of 100% humidity.

34. The process defined in claim 33 wherein said food products are unpackaged with a preprocessing step before the steam heating step comprising the surface wetting of the unpackaged product with a fine spray mist so that the surface becomes wet without dripping, thereby to effectuate an efficient heat transfer interface between the steam and the product in the cooking step.

35. The process defined in claim 33 including the concurrent step of flowing steam in contact with the products during the heating step and cold moist air into contact with the products during the cooling step while controlling humidity of the respective heating and cooling steam and moist air atmospheres to keep out water drops and thereby to prevent accumulation of water drops on the product and dripping along the flow path, thereby to assure product quality, good heating-cooling efficiency and to prevent unsanitary accumulation of deposits.

36. The process as defined in claim 35 wherein the control of humidity comprises respectively the steps of, flowing steam through the atmosphere of step (a) at a controlled rate, and flowing the controlled humidity moist air atmosphere at said temperature to establish the atmosphere of step (b) at a controlled rate to cool the products to substantially the cold air temperature without dehydration.

37. The process as defined in claim 33 including in step (b) the control of the cooling atmosphere by circulation flow of humid sanitary water stripped air about the product at a pressure above atmospheric thereby to cool the products efficiently in a short time without dehydration while avoiding contamination.

38. The process as defined in claim 33 including in step (a) the control of the heating atmosphere by the flow of live high humidity steam about the product and the discharge of the steam at a low rate reducing heat energy loss.

39. The process as defined in claim 33 including the step inserted betwee step (a) and step (b) of retaining atmospheric heat from the flow path from exiting the heating step before entry into the cooling step, thereby improving energy efficiency.

40. The process as defined in claim 33 with the steam heating temperature in the order of 99"C and the pressure greater than atmospheric to improve cooking efficiency in a short time period.

41. The process as defined in claim 33 with the cooling atmosphere provided by circulating air through a water spray chamber and stripping the air flow of any water droplets remaining before flowing about the product, thereby to reduce dripping or accumulation of contamination from the product.

42. The process as defined in claim 33 of preparing steam for the steam heating step and chilled moist air for the cooling step from sanitary water thereby to avoid carrying e:'ter- nal contamination into the process.

43. The process as defined in claim 33 including the step of increasing pressure of the heating and cooling steps above atmospheric, thereby to reduce losses of moisture from the product and to improve penetration of steam and cooling air residual temperatures into the product.

44. The process as defined in claim 43 including a step of partially controlling the pressure of the entire process by maintaining a pressure above atmospheric in a housing containing the flow path.

45. The process as defined in claim 33 wherein the flow path of the product is attained by passing a continuously running conveyor belt in sequence through the cooker and chiller and a sanitizing detergent bath.

46. The process defined in claim 33 wherein the heating and chilling are accomplished in separate compartments and the flow path of the product is attained by passing a continuosuly running conveyor belt through the heating and chiller compartments in sequence and back to the cooker in a path outside the heating and chilling compartments.

47. A food processing system substantially as herein before described with reference to the accompanying drawings.

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

49. A process of preparing food products substantially as hereinbefore described.