Title of Invention

A COMBINED INFRARED AND HOT AIR HEATING SYSTEM FOR FOOD PROCESSING

Abstract

A combined infrared and hot air heating system for food processing comprising a base frame (2) mounted horizontally on an endless stainless steel mesh conveyor(ll), characterized in that the said conveyor(l 1) having dual end drum (12a, 12b) , the said drums being connected to a prime mover, the said horizontal mesh conveyor passing through a plurality of horizontally placed insulated heating chambers (la, lb, lc) mounted on the said base frame (2), each of the said heating chambers being provided with plurality of infrared heating sources (6) on both sides of the said conveyor (11), each of the said chambers being provided with a top outlet (10) and louvered bottom inlet (19) connected to a hot air source (9,16,17,18), each of the said chambers also being provided with temperature sensors (7) connected to temperature controller (8) and conventional tuner device (15), the said conveyor being provided with end scrapper (20) and a controllable feed hopper (14).

Full Text

The present invention relates to a combined infrared and hot air heating system for food processing. The present invention particularly relates to a heating system providing infrared and hot air heating for processing food materials, which reduces the processing time and thereby improves the product quality* Infrared radiation is part of an electromagnetic radiation having wavelength in the range of 0.78|µm - 1000µm. Application of infrared heating is recently been adopted for use in certain food processing applications, because of its superiority in terms of costs and the product quality (color, organoleptic and nutritional value) as compared with conventional heating. Infrared heating offers many advantages over conventional heating under similar processing temperatures. Both the situations involve simultaneous heat and mass transfer and in case of infrared heating both are in same direction (from within to outside), while both are in opposite direction in case of conventional drying. This results in higher rate of heat transfer in case of infrared drying. When the substance is exposed to infrared radiation, the radiation first impinges on the surface of the material and penetrates it. Depending on the properties of the treated material and the temperature of the radiator on which the length of the wave depends, the infrared rays may be capable of penetrating into the depth of the material. On the increase of the radiator temperature, the wavelength decreases and the penetration depth increases. The incident radiation causes the change in the vibrational state of the atoms and molecules. When the frequency of the incident radiation is close to the value of the frequency of the natural oscillation of the atoms, then the amplitude of the imparted vibrations of the atoms increases. At the same time the coefficient of the energy absorption is also increased. The change in the vibrational state of the atoms and molecules generates heat energy within the material. When, in the process of irradiation, the infra-red penetrates the material sufficiently deeply (compared with its thickness), then by blowing cold air on to the surface, the surface temperature will be lower. In this case, the direction of moisture transfer will coincide with the direction of thermo-moisture migration. A greater effect can be achieved by applying intermittent irradiation and blowing cold air on to the material during the periods of non-irradiation. The heating of the material is thus quicker, the coefficient of moisture diffusion is increased, and, correspondingly, the shift of moisture towards the evaporation surface is intensified. Reference may be made to US patent US4257172 wherein a combination forced air and infrared dryer has been developed. The dryer consists of a facility in which the product sequentially passes beneath an array of ventilating nozzles and an array of infrared heaters. Each heater is covered by a semi-cylindrical reflector having thin edges spaced apart to form ventilating passages. The drawback of this system is the individual semi-cylindrical reflectors which will restricts the flow of air and also will provide a concentrated localized heating on to the conveying unit. Due to this a number of such arrangements have to be used to cover the entire range of the product on the conveyor. Since, multiple nozzles are used, the overall cost of the system may be high. Reference may be made to US patent US5668921 where in a hot air dryer with infrared heater and split shaped outlet is used. The dryer consists of a housing with a slit through which warm air is blown. The housing also consists of infrared irradiators. The infrared irradiators are housed inside a radiation permeable wall and the product to be heated is exposed to the radiation through this wall. The disadvantage of this system is that, it is not continuous, the infrared radiators are housed inside the walls and the product is not directly exposed to the infrared radiation. This may restrict the maximum temperature attainable and the direct effect of infrared radiation on to the product, which will have additional influences in terms of internal heat generation. Reference may be made to US patent US3900959 where in an apparatus of photographic film with impregnated water is explained. The system consists of a drying chamber with rollers for conveying the film into the drying chamber. The air is blown at the surface at 35°C across the conveyor. The disadvantage of this system is that it is suitable for drying ink and not for food applications. The air is blown at 35°C only, which is not sufficient for drying of the product. The product is conveyed through rip rollers, which is suitable for conveying sheets and not for granular food materials. Reference may be made to US patent US4693013 where in an infrared dryer is described. It includes an operating duct infrared radiators are mounted on a pivoted axes for rotating the radiators 180°C. Three pivoted axes are in turn mounted on to the walls of the duct. Three systems are made suitable for'drying of textile fabric webs. Air is blown through the ducts. The disadvantage of this system are that they not suitable for fragile food material as they have to pass through the ducts. Air is sucked and not blown which may not provide the required draft to remove the surface moisture. The main object of the present invention is to provide a heating system for the processing of food materials, which obviates the drawbacks of the known processes as detailed above. Another object of the present invention is to provide a heating system, which can increase the mass transfer in the food material processed and reduce the processing time. Still another object of the present invention is to provide a heating system, which can result in a product with better organoleptic property. Still another object of the present invention is to provide a heating system, for any heating based unit operations in food processing like blanching, cooking, drying, roasting or baking. In the drawing accompanying this specification figure 1 and figure 2 represents the front view the side view of the schematic diagram of combined infrared and hot air heating system for food processing. The equipment of the present invention provides, a combined infrared and hot air heating system for food processing which comprises of three numbers of insulated heating chambers (1; a,b,c) of equal length mounted on a Mild steel base frame (2), with mirror finished inner surface (3) for maximum reflection of infrared radiation, a curvature (4) of optimum radius for maximum reflection of infrared radiation onto the material on both the top and bottom side of the chamber wall, a gap (5) is provided between zones for tempering of the material, mid wave quartz infrared tubes (6) of specific wavelength (2.4 to 3.0 urn) on both top and bottom side of the conveyor for infrared heating of food material, a temperature sensor (7) for monitoring individual chamber temperature connected to temperature controller (8), an insulated hot air distributor (9) on bottom side of the heating chamber for convective heating of the material, an opening (10) on topside of the chamber for the moist air to escape, a stainless steel wire mesh conveyor (11) with roller chain at the edges placed over two drums (12; a,b) with sprocket (13) at the edges for proper conveyor alignment, a feed hopper (14) with a manually operated gate to control the feed, an ONOFF timer device (15) to control the residence time of the processing material, a blower (16) to blast the air, an electrical finned tube heater (17) for generation of hot air, a manual controller (18) in each duct for regulating the flow of hot air to the chamber, louvers (19) near the hot air entry point to the chamber to ensure uniform distribution of hot air throughout the heating chamber, a product scrapper (20) for removal of product from the conveyor. Accordingly, the present invention provides a combined infrared and hot air heating system for food processing comprising a base frame (2) mounted horizontally on an endless stainless steel mesh conveyor(11) , characterized in that the said conveyor(11) having dual end drum (12a, 12b) , the said drums being connected to a prime mover, the said horizontal SS mesh conveyor passing through a plurality of horizontally placed insulated heating chambers (1a, 1b, 1c) mounted on the said base frame (2), each of the said heating chambers being provided with plurality of infrared heating sources (6) on both sides of the said conveyor (11), each of the said chambers being provided with a top outlet (10) and louvered bottom inlet (19) connected to a hot air source (9,16,17,18), each of the said chambers also being provided with temperature sensors (7) connected to temperature controller (8) and conventional tuner device (15), the said conveyor being provided with end scrapper (20) and a controllable feed hopper (14). with a manually operated gate to control the feed, an ONOFF timer device (15) to control the residence time of the processing material, a blower (16) to blast the air, an electrical finned tube heater (17) for generation of hot air, a manual controller (18) in each duct for regulating the flow of hot air to the chamber, louvers (19) near the hot air entry point to the chamber to ensure uniform distribution of hot air throughout the heating chamber, a product scrapper (20) for removal of product from the conveyor Accordingly, the present invention provides a combined infrared and hot air heating system for food processing comprising a base frame (2) mounted horizontally on an endless stainless steel (SS) mesh conveyor(11) , characterized in that the said conveyor(11) having dual end drum (12a,12b) , the said drums being connected to a prime mover, the said horizontal SS mesh conveyor passing through a plurality of horizontally placed insulated heating chambers (1a, 1b, 1c) mounted on the said base frame (2), each of the said heating chambers being provided with plurality of infrared heating sources (6) on both sides of the said conveyor (11), each of the said chambers being provided with a top outlet (10) and louvered bottom inlet (19) connected to a hot air source (9,16,17,18), each of the said chambers also being provided with temperature sensors (7) connected to temperature controller (8) and conventional tuner device (15), the said conveyor being provided with end scrapper (20) and a controllable feed hopper (14). The equipment of the present invention provides, which is referred to as MODE 1, the development of a heating system with hot air, generated by an electrically heated heat source and a blower. MODE 2, the system for infrared heating, with an infrared source like quartz, ceramic, which are electrically heated or by any other means like gas. MODE 3, the system for combined hot air and infrared heating, with hot air generated by electrical or any other means and an infrared source like quartz, ceramic which are electrically heated or by any other means like gas. The novelty of the present system is that it is a combined infrared and hot air heating system suitable for food applications. The chamber design is critically designed to have maximum radiation on to the conveyor belt. The infrared source is selected that is most suitable for food applications. The system is continuous conveyor and modular type suitable for large-scale food processing applications. This unit is a versatile processing facility for any heating based unit operations that can be used for blanching, cooking, drying, roasting and baking. The combination of hot air and infrared heating reduces the overall processing time and there by increases the orgenoleptic quality of the product. The unit also facilitates increase in the mass transfer flux due to the combined effect of hot air and characteristic infrared radiation, which is a part of electromagnetic radiation. Since the unit has infrared source on both top and bottom of the conveyor, in staggered pattern, the heating is more uniform and the quality of the final product is better as compared to conventional processing. The invention as applied to food processing can be operated in three different modes to heat the product. Mode 1: Conventional hot air heating Mode 2: Infrared heating Mode 3: Combined infrared and hot air heating When using in MODE 1 the hot air temperature is set to the required value on the panel. The actual temperature of the hot air is measured by a thermocouple sensor provided at the outlet of electrical heater. The set and the actual values are indicated by the digital indicator. The process begins by switching ON the blower and electrical heater. The airflow rate is controlled by altering the position of the gate provided at the air entry point of the blower. Once the chamber temperature reaches the targeted value, the material is fed on to the continuous stainless steel wire mesh conveyor. The material bed thickness is maintained at the required level through a scooping arrangement provided at the bottom of the feed hopper. The residence time of the material is controlled by varying the conveyor speed through ON - OFF timer controller (5 to 150 minutes). The temperature controller monitors the chamber temperature to the set value. The hot air temperature may be varied if required during the course of heating to prevent the material from overheating. Once the material is sufficiently heat processed, the product is taken out at the exit of the heating system. When using MODE 2, the required temperature is set for individual chambers. The chamber temperature is measured by individual temperature sensors provided above the conveyor. The actual and set values are indicated by the digital datalogger. The process begins by switching ON the infrared heaters. Once4he chamber temperature reaches the targeted value, the material is fed on to the continuous stainless steel wire mesh conveyor. The material bed thickness is maintained at the required level through a scooping arrangement provided at the bottom of the feed hopper. The residence time of the material is controlled by varying the conveyor speed through ON - OFF timer controller. The temperature controller monitors the chamber temperature. The infrared temperature may be varied if required during the course of heating to prevent the material from overheating. Once the material is sufficiently heat processed, the product is taken out at the exit of the heating system. When using in MODE 3, the required temperature is set for individual chambers. The hot air temperature is also set for convective heating. The actual temperature of the hot air is measured by the thermocouple sensor provided at the outlet of electrical heater. The chamber temperature is measured by individual temperature sensors provided above the conveyor. The actual and set temperature of the individual chamber are indicated by the digital datalogger. The actual and set hot air temperature is indicated by the digital indicator. The process begins by switching ON the blower, heater for hot air and infrared heaters. The rate of airflow is controlled by altering the position of the gate provided at the air entry point of the blower. Once the chamber temperature and hot air temperature reaches the targeted value, the material is fed on to the continuous stainless steel wire mesh conveyor. The material bed thickness is maintained at the required level through a scooping arrangement provided at the bottom of the feed hopper. The residence time of the material is controlled by varying the conveyor speed through ON - OFF timer controller. The temperature controller monitors the chamber temperature to the set value. The hot air temperature may be varied if required during the course of heating to prevent the material from overheating. The infrared temperature may be varied if required during the course of heating to prevent the material from overheating. Once the material is sufficiently heat processed, the product is taken out at the exit of the heating system. Accordingly, the present invention provides a combined infrared and hot air heating system for food processing comprising a base frame (2) mounted horizontally endless stainless steel mesh conveyor (11) having dual end drum (12a,12b), the said drums being connected by conventional means to a prime mover, the said horizontal SS mesh conveyor passing through a plurality of horizontally placed insulated heating chambers (1a,1b,1c) mounted on the said base frame (2), each of the said heating chambers being provided with a plurality of infra red heating sources (6) on both sides of the said conveyor (11) passing through each of the said chambers, each of the said chambers being provided with a top outlet (10) and louvered bottom inlet (19) connected to a hot air source (9,16,17,18), each of the said chambers also being provided with conventional temperature sensors (7) connected to temperature controller (8) and conventional tuner device (15), the said conveyor being provided with end scrapper (20) and a controllable feed hopper (14). In an embodiment of the present heating system the said heating chambers may be provided with end curvature (4) and inner mirrored surface capable of maximizing the reflection of infrared rays. In another embodiment of the present heating system infrared source (6) used may be selected from radiating electromagnetic energy in the range of 2.4u mto3.0|jm. Yet in another embodiment of the present heating system the heating source used may be selected from mid wave quartz Infrared tube, ceramic infrared tube. Still in another embodiment of the present heating system the hot air source used may consist of a conventional blower (16) connected to the louvered inlet (19) through a duct (9) having a finned tube heater (17) and manual controller (18). The advantages of the system are: The referred system is a combine infrared and hot air heating system suitable for food applications. The chamber design is critically designed to have maximum radiation on to the conveyor belt. The infrared source is selected that is most suitable for food applications. The system is a continuous conveyor and modular type suitable for large-scale food processing applications. This unit is a versatile processing facility for any heating based unit operations that can be used for blanching, cooking, drying, roasting and baking. The combination of hot air and infrared heating reduces the overall processing time and there by increases the organoleptic quality of the product. The unit also facilitates increase in the mass transfer flux due to the combined effect of hot air and characteristic infrared radiation as a part of electromagnetic radiation. Since the unit has infrared source on both top and bottom of the conveyor, in staggered pattern, the heating is more uniform and the quality of the final product is better as compared to conventional processing We claim: 1. A combined infrared and hot air heating system for food processing comprising a base frame (2) mounted horizontally on an endless stainless steel mesh conveyor(11), characterized in that the said conveyor(11) having dual end drum (12a, 12b) , the said drums being connected to a prime mover, the said horizontal mesh conveyor passing through a plurality of horizontally placed insulated heating chambers (1a, 1b, 1c) mounted on the said base frame (2), each of the said heating chambers being provided with plurality of infrared heating sources (6) on both sides of the said conveyor (11), each of the said chambers being provided with a top outlet (10) and louvered bottom inlet (19) connected to a hot air source (9,16,17,18), each of the said chambers also being provided with temperature sensors (7) connected to temperature controller (8) and conventional tuner device (15), the said conveyor being provided with end scrapper (20) and a controllable feed hopper (14). 2. A combined infrared and hot air heating system as claimed in claim 1, wherein the said heating chambers are provided with end curvature (4) and inner mirrored surface. 3. A combined infrared and hot air heating system as claimed in claims 1 & 2, wherein infrared source (6) used is radiating electromagnetic energy in the range of 2.4 µm to 3.0µm. 4. A combined infrared and hot air heating system as claimed in claims 1-3, wherein the heating source used is selected from mid wave quartz infrared tube, ceramic infrared tube. 5. A combined infrared and hot air heating system for food processing substantially herein described with reference to the drawings accompanying this specification.

Documents:

336-DEL-2002-Abstract-(09-06-2008).pdf

336-DEL-2002-Abstract-(13-06-2008).pdf

336-DEL-2002-Abstract-(21-08-2008).pdf

336-DEL-2002-Abstract-27-05-2008.pdf

336-del-2002-abstract.pdf

336-DEL-2002-Claims-(09-06-2008).pdf

336-DEL-2002-Claims-(13-06-2008).pdf

336-DEL-2002-Claims-(21-08-2008).pdf

336-DEL-2002-Claims-27-05-2008.pdf

336-del-2002-claims.pdf

336-DEL-2002-Correspondence-Others-(09-06-2008).pdf

336-DEL-2002-Correspondence-Others-27-05-2008.pdf

336-del-2002-correspondence-others.pdf

336-DEL-2002-Correspondence-PO.pdf

336-DEL-2002-Description (Complete)-(21-08-2008).pdf

336-del-2002-description (complete)-09-06-2008.pdf

336-del-2002-description (complete)-13-06-2008.pdf

336-del-2002-description (complete)-27-05-2008.pdf

336-del-2002-description (complete).pdf

336-DEL-2002-Drawings-(09-06-2008).pdf

336-del-2002-drawings.pdf

336-DEL-2002-Form-1-(21-08-2008).pdf

336-del-2002-form-1.pdf

336-DEL-2002-form-18-(13-06-2008).pdf

336-DEL-2002-Form-18-(21-08-2008).pdf

336-del-2002-form-18.pdf

336-DEL-2002-Form-2-(13-06-2008).pdf

336-del-2002-form-2.pdf

336-DEL-2002-Form-3-(09-06-2008).pdf

336-DEL-2002-Form-3-27-05-2008.pdf

336-del-2002-form-3.pdf