WO2006087753A1

WO2006087753A1 - Microwave diffuser

Info

Publication number: WO2006087753A1
Application number: PCT/IT2006/000075
Authority: WO
Inventors: Enrico Ranchetti
Original assignee: Enrico Ranchetti
Priority date: 2005-02-18
Filing date: 2006-02-14
Publication date: 2006-08-24
Also published as: ITBS20050018A1

Abstract

The invention concerns a microwave diffuser, for trays to contain products to be heated, cooked or sterilised in conditioning equipment through the use of microwave irradiation. The diffuser comprises shielding components (14, 15) associated with the side walls of each tray made of a microwave impermeable material and which is also capable of reflecting said microwaves and provided to stop the flow of the microwaves from outside into the tray through the side walls and to reflect the microwaves from the side walls of the tray towards the centre of the product it contains.

Description

"MICROWAVE DIFFUSER"

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Field of the Invention This invention concerns the heating, cooking or sterilising equipment sector in general, where irradiation is by means of microwaves for foodstuffs packed in tubs or trays and refers in particular to an innovative tray for this kind of treatment. State of the Art The use of microwaves as a source for heating, cooking or sterilising foodstuff placed in trays which are permeable to microwaves, the most common material being plastic, is already well known. In the industrial field, these treatments can be carried out on a continuous basis in a conditioning tunnel as described for example in the application for the Italian Patent TV2002A000120. In the catering, community or domestic level on the other hand they are carried out in microwave ovens. As a precautionary measure the trays can be sealed and taken through or simply deposited in the treatment chamber singularly, or in batches, on baking trays.

However irradiation by microwaves is not only from above but through the side walls of the trays. In this case the risk is to overheat or however to have excess heating of the contents in the areas next to the walls compared to the contents occupying the central parts causing what is known as a "cold spot", so much so that the product contained in the tray becomes heated, cooked, sterilised, that is treated, not uniformly in the various zones it occupies sometimes with causing results which are incorrect if not unacceptable at least as far as sterilisation is concerned. In the attempt to have a more uniform irradiation of the products in trays during treatment using microwaves, the idea of having the trays was put forward, with the disadvantage however that the equipment became more complicated without however achieving better results. Objectives and Summary of the Invention One of the objectives of this invention is to avoid the above mentioned inconveniences and to create the conditions whereby treatment of all the contents of the trays when radiated by a microwave source are more uniform and to eliminate or at least to noticeably reduce the unwanted "cold spot" effect. Another objective of the invention is to eliminate the necessity to turn the tray during irradiation, with consequent simplification of the treatment equipment.

These objectives are achieved with a microwave diffuser according to claim 1 and therefore characterised by shielding components associated with the side walls of each tray, but of a microwave impermeable material and at the same time able to reflect them so as to block the flow of microwaves from the outside to the inside through the side walls of the tray and to reflect the microwaves from the side walls of the tray towards the centre of the mass of product it contains. Brief Description of the Drawings

More details will however become evident from the following description made in reference to the enclosed indicative and not limiting drawings, in which: Fig. 1 shows a cross section of the microwave diffuser in one of its forms;

Fig. 2 shows a similar cross section of a microwave diffuser in another possible form; and

Ia Fig. 3 shows a view in perspective of a microwave diffuser with cavities for the treatment of multiple trays. Detailed Description of the Invention

In the embodiment shown schematically in Fig. 1 , the microwave diffuser comprises a supporting component 11 with at least one opening 12 to receive and hold a tray 13, which can be removed, for foodstuffs to be heated, cooked, sterilised or simply to defreeze if coming from the freezer, the trays usually being made of a plastic material which is microwave permeable. The tray can be of any shape, size and depth with a rim protruding outwards.

The opening 12 is provided with fins 14 around it forming a shield which is shaped and sized so as to fit against the external surface of the side walls 12' of the tray 13.

The support component can be either with one opening for a single tray or also in the shape of a tray with as many opening as number of trays of product, as shown in Fig. 3, for use, in this case and advantageously, in the industrial sector during simultaneous treatment of a number of trays of product made to pass for example through a conditioning tunnel like the one described in the abovementioned application for a patent.

The supporting component 11 and relative fins 14 are made of a microwave impermeable material which is at the same time capable of reflecting them. Therefore, the shield formed by the fins 14 around each opening 12 forms a barrier which prevents the flow of microwaves from outside towards the inside through the side walls of the tray and which at the same time reflect the microwaves irradiated from the top or through the bottom of the tray towards the centre of the product placed inside it. In another form, as shown in Fig. 2, the shield, which is microwave impermeable and at the same time capable of reflecting them, is made up of sheets or foil 15 of an appropriate material either applied to the external surface or even let into the side walls of the tray.

Both the fins 14 forming a shield around the side walls of each tray, whether sheets or foil 15 forming a shield applied directly or let into the side walls of each tray the surfaces of which can be solid or perforated, and when designed to be on the outside of the walls of the tray they can be covered with a film of protective material.

At all events, the microwave diffuser described above and positioned between the tray of product to be treated and the irradiation source, acts as a shield against the microwaves, stopping them from passing through the side walls. In this way the contents of the tray is irradiated only from the top and should it be necessary from the bottom, with a result that treatment is more uniform and there is a noticeable reduction in the "cold spot" effect.

Claims

"MICROWAVE DIFFUSER"CLAIMS

1. A microwave diffuser, in particular for trays made to contain products to be heated, cooked or sterilised in conditioning equipment through the use of microwave irradiation, characterised by shielding components (14, 15) associated with the side walls of each tray, made up of microwave impermeable material which is also able to reflect them and is provided to stop the flow of the microwaves from the outside into the tray through the side walls and to reflect the microwaves from the side walls of the tray towards the centre of the product contained in it. .

2. A microwave diffuser according to claim 1 , characterised by the fact that it contains a supporting component with at least one opening provided to receive and hold a tray, which can be removed, and fins (14) positioned around said opening and forming a shield, shaped and sized so as to fit against the external surface of the side walls of the tray.

3. A microwave diffuser according to claim 2, in which said supporting component has the same number of openings as the number of trays to be housed and shielding fins around each opening.

4. A microwave diffuser according to claims 2 and 3, in which said shielding fins (14) are solid or perforated.

5. A microwave diffuser according to claims 2-4, in which said shielding fins (14) are covered with a protective material.

6. A microwave diffuser according to claim 1 , in which the shielding components are made of sheets or foil (15) applied directly to the external surface of the side walls of the tray.

7. A microwave diffuser according to claim 6, in which said sheets or foil are covered with a protective material.

8. A microwave diffuser according to claim 1 , in which the shielding components are made of sheets or foil set into the side walls of the tray.

9. A microwave diffuser according to claims 6-8, in which the surfaces of said shielding sheets or foil are solid or perforated (15)