AU728298B2

AU728298B2 - Microwave bulk material melting apparatus

Info

Publication number: AU728298B2
Application number: AU86195/98A
Authority: AU
Inventors: Luke Nadj
Original assignee: Illawarra Technology Corp Ltd
Current assignee: Illawarra Technology Corp Ltd
Priority date: 1997-08-08
Filing date: 1998-08-10
Publication date: 2001-01-04
Anticipated expiration: 2018-08-10
Also published as: AU8619598A

Description

WO 99/08488 PCT/AU98/00630

'I

MICROWAVE BULK-MATERIAL MELTING APPARATUS Field of the Invention The present invention relates to the field of bulk material melting in product preparation, such as in the production of food.

Background of the Invention Several methods of product preparation involve as a preliminary step the melting of substantial amounts of bulk source material, e.g. the production of chocolate in a confectionery plant. The melting of blocks of typically kg of bulk fat is currently performed utilising a 'hot pipe' method, in which the blocks are placed above a pipe system exhausting steam from a boiling fluid passed through the pipes. The molten fat is collected and stored for further processing or transferred in its fluid state directly to the next production step.

This method has several disadvantages. The steam or water temperature is typically much higher than the required melting temperature of the bulk fat, giving rise to an enhanced oxidation of the fat in the 'steam' environment (eg. typically of the order of 80 0 C in a water steam ambient compared to a fat melting temperature of typically 40°C). Oxidation of fat is known to shorten the shelf life of fat based food significantly.

A further disadvantage lies in the limited mobility of the melting apparatus as described above, since it includes a complex 'hot pipe' heating system with requirements such as water ducting means, water storing means or connecting means to an existing water supply and boiling means.

Similar disadvantages apply, for example, in the preparation of pharmaceutical products in which the exposure of the bulk source material to temperatures above the melting point of the bulk material is not desirable.

Statement of Invention In one aspect, the present invention provides a method WO 99/08488 PCT/AU98/00630 2 of product preparation in which a preliminary step includes melting of a bulk source material, the method including loading bulk source material into a microwave cavity, energising a microwave source to melt the bulk source material due to an interaction of the microwaves with the bulk source material, collecting the melted source material and discharging the melted source material outside the microwave cavity.

In a second aspect, the present invention provides an apparatus for melting bulk material, the apparatus comprising a microwave cavity having means for receiving and supporting the bulk material, a microwave source for supplying microwave energy to the cavity, means for collecting in liquid phase molten material from the bulk material and means for discharging the molten material outside the cavity for use in a food product preparation process.

Preferably, the microwave source comprises a plurality of magnetrons and advantageously more than 10 magnetrons, which preferably operate at frequencies above 900MHz.

Further, the apparatus includes a cooling system for the microwave source comprising a ducting means for feeding hot air from the microwave source into the microwave cavity.

Further, the discharging means comprises substantially a gravity discharge system and the collecting means includes a filtering means, the filtering means being adjacent to a connecting means to the discharging means.

Preferably, the plurality of magnetrons includes different polarities of the magnetrons and the apparatus includes an automatic cut off means for the microwave source, which is activated when the solid object is substantially molten.

Advantageously, the apparatus is supported by a mobile supporting means.

WO 99/08488 PCT/AU98/00630 3 Brief Description of the Drawings Notwithstanding any other embodiments which may fall within the scope of the present invention, one preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, which: Fig. 1 is an isometric view of a bulk fat melting apparatus constructed in accordance with the preferred embodiment.

Fig. 2 is a front view of a bulk fat melting apparatus constructed in accordance with the preferred embodiment.

Fig. 3 is a plan view of a bulk fat melting apparatus constructed in accordance with the preferred embodiment.

Fig. 4 is a side view of a bulk fat melting apparatus constructed in accordance with the preferred embodiment.

Description of One Preferred Embodiment Turning initially to Fig. i, there is shown an isometric view of a bulk fat melting apparatus 1 constructed in accordance with the preferred embodiment.

A

microwave apparatus 10 is supported by a frame 11 comprising vertical posts 12, horizontal rails 13 interconnecting the vertical support posts and wheels 26 attached to posts 12.

One wall of the microwave apparatus is formed by a door 14, which can be swung open and closed and which also forms one wall of the cavity 15 for receiving and supporting objects in the microwave field 16. The cavity includes a grille 25 for supporting the objects.

A fan 17 is attached to one wall of the apparatus. Air is supplied to the fan through an air supply channel 18 and circulated passed the microwave source 19 and through ducting pipes 20. While passing the microwave source 19, the air transports heat from the microwave source resulting in a temperature increase of the air. The hot air is then fed into the cavity 15 from the ducting pipes 20 through ports 2. This hot air is utilised in assisting in the WO 99/08488 PCT/AU98/00630 4 melting of an object in-the cavity Microwave electronic equipment 22, 23 is provided, including an automatic cut-off circuit sensing when an object placed in the cavity 15 is substantially melted. A control panel 24 is attached to the microwave apparatus for operating the microwave apparatus via the electronic equipment 22,23. A cover 27 is also provided (ghost lines in Fig. 1) covering the microwave apparatus 10, the ducting pipes 20, the fan 17 and the microwave electronic equipment 22, 23.

Turning now to Fig. 2 there is shown a front view of the bulk fat melting apparatus 1 constructed in accordance with the preferred embodiment. The bottom 30 of the cavity (Fig. 1) is tapered 31 to collect and drain the molten fat. The molten fat flows through the grille structure (Fig. 1) into the bottom 30 of the cavity. An outlet filter 32 is provided to limit solids from escaping before being melted. The filter 32 is also used to dam molten fat within the bottom 30 of the cavity 15 (Fig. 1) to increase its temperature 3 0 -4 0 C to ensure the complete melting of the fat. The filter 32 is adjacent to choke 33 which comprises an outlet valve 34.

In Fig. 3 a plan view of the bulk fat melting apparatus 1 constructed in accordance with the preferred embodiment is shown and in Fig. 4 a side view of the bulk fat melting apparatus 1 constructed in accordance with the preferred embodiment is shown.

Fig. 1-4 show an example bulk fat melting apparatus 1, which could be used for melting bulk fat in a confectionery plant utilising the following steps: The bulk fat (typically a block of 25kg) is received in the cavity 15 of the microwave apparatus supported by the grille 25 and the door 14 shut.

The microwave source 19 and cooling fan 17 are energised utilising the control panel 24.

Due to the interaction of the microwaves with the WO 99/08488 PCT/AU98/00630 bulk fat (assisted by the hot air fed into the cavity through the ports 21), the temperature of the fat increases. When the temperature of parts of the bulk -fat reaches its melting point, these parts melt and the fat in its liquid state flows trough the grille 25 into the bottom of the cavity 15. The melting of a solid in the microwave field proceeds from the outer surface of the solid and the size of the solid fat block is gradually reduced. Preferably, the temperature of the air surrounding the solid fat will not exceed the melting temperature of the fat (typically 40 0

C).

The molten fat is collected in the tapered bottom of the cavity 15 outside the microwave field 16. The grille 25 prevents bigger portions of unmelted fat to enter the bottom portion 30 of the cavity 15. Further, there is provided a filter 32, which ensures that solid fat particles that fit through the grille 25 are not drained out of the bottom 30 of cavity 15 through choke 33 and outlet valve 34. The filter 32 is constructed so as to dam the molten fat in the tapered bottom 30 of the cavity This results in an additional temperature increase of 3'-4 0

C

to ensure the melting of solid fat particles that fall through the grille 25 but are confined in the bottom 30 of cavity 15 by the filter 32.

It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the preferred embodiment without departing from the spirit or scope of the invention. The preferred embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive.

WO 99/08488 PCT/AU98/00630 6-- The invention which will be claimed will be any novel arrangement described herein and may include the following: i. A method of product preparation in which a preliminary step includes melting of a bulk source material, the method including: loading bulk source material into a microwave cavity, energising a microwave source to melt the bulk source material due to an interaction of the microwaves with the bulk source material, collecting the melted source material, and discharging the melted source material outside the microwave cavity.

2. An apparatus for melting bulk material, the apparatus comprising a microwave cavity having means for receiving and supporting the bulk material, a microwave source for supplying microwave energy to the cavity, means for collecting in liquid phase molten material from the bulk material, and means for discharging the molten material outside the cavity for use in a food product preparation process.

3. An apparatus as claimed in claim 2 wherein the microwave source comprises a plurality of magnetrons.

4. An apparatus as claimed in claims 2 and 3 wherein the number of magnetrons is more than 5. An apparatus as claimed in any one of claims 2 to 4 wherein the magnetrons operate at frequencies above 900MHz.

6. An apparatus as claimed in any one of claims 2 to 5 further including a cooling system for the microwave source comprising a ducting means for feeding hot air from the microwave source into the microwave cavity.

Claims

1. A method of food preparation which includes melting a fat component from a block of solid source material and using the melted component in preparing food, the method including: loading bulk source material into a melted zone of a microwave oven having means to support the source material, energising a multiplicity of microwave sources disposed around the melting zone and arranged to establish a substantially uniform microwave field throughout the melted zone so as to melt a fat component from the bulk source material due to an interaction of the microwaves with the bulk source material, collecting the melted component for use in a food manufacturing process; discharging the melted component outside the microwave oven, and 20 using the melted component in a food manufacturing process.

2. An apparatus arranged for use in a food production method and wherein the apparatus melts fat component from S: 25 a block of solid source material and is arranged to supply e the melted fat material to a subsequent food manufacturing go processing station, the apparatus including: a microwave oven having means for receiving and supporting the solid material in a melting zone in the 30 oven, a multiplicity of microwave sources for supplying microwave energy to the melting zone cavity, and establishing a substantially uniform microwave field through the melting zone and avoiding cross-coupling means for collecting the melted fat component for use in a food production process, S(d) means for discharging the molten material 8 outside the melting zone, and the multiplicity of microwave sources comprises approximately 10 magnetrons to provide the source of microwaves, each magnetron being air cooled with the warmed discharged cooling air being directed into the melting zone, the microwave oven having a front access door and being portable.

3. An apparatus as claimed in claim 2 wherein the microwave sources are arranged to operate at frequencies above 900MHz.

4. An apparatus as claimed in claim 2 or claim 3 wherein the discharging means comprises a gravity discharge system. An apparatus as claimed in any one of claims 2 to 4 0 wherein the collecting means includes a filtering means. 0 6. An apparatus as claimed in claim 5 wherein the filtering means is adjacent to a connecting means to the discharging means. oo 25 7. An apparatus as claimed in any one of claims 2 to 6 wherein the microwave sources comprise magnetrons having o.0. oo different polarities.

8. An apparatus as claimed in any one of claims 2 to 7 30 and further including an automatic cut off means for the 0 microwave sources.

9. An apparatus as claimed in any one of claims 2 to 8 wherein the automatic cut off means is adapted to be activated when the solid source material is substantially melted 9 An apparatus as claimed in any one of claims 2 to and having a mobile supporting means.

11. A method of food preparation substantially as here and described with reference to the accompanying drawings.

12. An apparatus for use in food preparation substantially as hereinbefore described with reference to the accompanying drawings.

13. A food product prepared using the method of claim 1 or claim 11 or the apparatus of any one of claims 2-10 or 12. *g e WO 99/08488 PCT/AU98/00630 means for collecting the molten material for use in a food production process; and further comprising providing approximately magnetrons to provide the source of microwaves, each magnetron being air cooled with the warmed discharged cooling air being directed into the melting zone, the microwave oven having a front access door and being portable.

14. A method of food preparation comprising using a melted fat containing ingredients melted from a solid block by the method of claim 1 or by using the apparatus of any one of claims 2 to 13. AMENDED SHEET (ARTICLE 19)