GB2252027A

GB2252027A - Oven shelf for a microwave heating oven

Info

Publication number: GB2252027A
Application number: GB9200853A
Authority: GB
Inventors: Jae Chul Choi
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-01-18
Filing date: 1992-01-15
Publication date: 1992-07-22
Also published as: GB9200853D0; CN1063348A; CA2059083A1; FR2673502A1; DE4200708A1; JPH0521155A

Abstract

A microwave oven shelf (1) is provided with a microwave absorber (3). The microwave absorbing material may be conventional ferrite, carbon, dielectric, carbon ferrite or far infrared radiating material. The microwave absorbing material may be dispersed in a silicon resin of good heat resistance and then attached to a conventional oven shelf. It may be dispersed in a suspension or glaze and then attached to a conventional oven shelf by spraying or deposition. It may form projections or occupy bores or grooves in the shelf. The shelf may be a turntable. <IMAGE>

Description

221522j27 1 OVEN TRAY FOR A MICROWAVE HEATING OVEN This invention relates

to a tray and particularly to an oven tray for use in a microwave oven.

A conventional microwave oven is provided with an oven tray to support a cooking tray which may be put thereon.

When the food on the cooking tray is heated, the heat from the food is conducted to the cooking tray and then to the oven tray. Thereafter, the heat radiates to the outside of the oven causing energy loss. Furthermore, in case that the oven tray is made of gl ass or ceramic material, it may be broken by the conducted heat.

In addition, there may be microwave energy leakage from a gap between a cavity def ined by a cabinet and the cabinet door. Such leakage of microwave energy is harmful to the human body and generates noise in electronic equipment around the oven.

Thus, it is conventional to provide a microwave absorber between the front face of the microwave oven and a microwave oven door, or to design a gap between a door and the front f ace of the microwave oven to be less than 0.6 mm. This type of microwave oven is disclosed in U.S. Patent Nos. 3,866,009, 4,602,141, 4,525,614 and 4,046,983 issued respectively on 11th February, 1975, 22nd July, 1986, 25th June, 1985 and 6th September, 1977 and U.K. patent No. 2,083,329. This type of microwave oven has disadvantages in that an excessive amount of the microwave energy may leak during operation of the oven in empty state and that it is difficult to manufacture a microwave oven having a 2 gap of less than 0.6 nm, thus lowering productivity.

An object of the present invention is to provide an oven tray which produces substantially no heat energy loss, thus resulting in fast cooking of the food.

Another object of the present invention is to provide an oven tray which facilitates the manufacturing of a microwave oven.

Still another object of the present invention is to provide an oven tray which is less likely to be broken over extended use.

Yet another object of the present invention is to provide an oven tray which prevents microwave energy leakage f rom a gap between the oven door and the cavity.

The present invention is defined in the accompanying claims to which reference should now be made.

To achieve the above objects, a microwave absorber is incorporated in the conventional oven tray. During operation of a microwave heating oven, the oven tray of the present invention absorbs extra microwave energy and generates slightly more heat than the heat of the food, whereby the heat from the food may be prevented from being conducted to the oven tray causing no energy loss, the food in a cooking tray over the oven tray is cooked more quickly, and the oven tray may not be broken by the conducted of heat. Since, in addition.. far infrared rays are radiated from the microwave absorbing material, the taste of the food is improved. Furthermore, since the underside of the cooking tray contacts the microwave absorber, a rotary oven tray is less likely to slip.

g; 3 The present invention can be put into practice in various ways some of which will now be described with reference to the accompanying drawings, in which:

Figure 1 is a sectional view of a first embodiment of an oven tray of this invention; Figure 2 is a sectional view of a second embodiment of an oven tray of this invention; Figures 3A and 3B are plan views of the second embodiment of an oven tray of this invention; Figure 4 is a sectional view of the third embodiment of an oven tray of this invention; Figures SA and 5B are plan views of the third embodiment of an oven tray of this invention; Figure 6 is a sectional view of a fourth embodiment of an oven tray of this invention; Figure 7 is a plan view of the fourth embodiment of an oven tray of this invention; and Figure 8 is a sectional view of a fifth embodiment of an oven tray of this invention.

Referring to Figure 1, a conventional rotary tray 1 which is made of metal, glass or ceramic material, is provided with a driving shaft receiving recess 2. A microwave absorber 3 is provided on the-surface of the oven tray.

Thq microwave absorber 3 is made of ferrite, carbon, dielectric, carbon 'ferrite material. or a farinfrared radiating material. The microwave absorber 3 is of flat or non-flat configuration and attached to the tray by, for example, one of the following two ways. First, the abovedescribed microwave absorbing materials are dispersed in a silicon resin of good heat-resistance and then attached to the tray.

Secondly, the microwave absorbing materials are 4 dispersed in a suspension vehicle or glaze, and then attached to the tray by means of spraying or deposition.

In Figure 1, the microwave absorbing material is attached to both sides of the tray, but it may be attached to the one side of the tray. The thickness of the above-described absorbing material may be different depending on the kind of the material, but it is desirable that the thickness be minimized. However, the thickness should be dimensioned such that the microwave absorbing material can generate a slightly higher degree of heat than that from the food, since the microwave absorbing materials have the characteristic that, once they absorb microwave energy, it is converted into heat energy.

It is preferable that the microwave absorbing material is made of carbon f errite and it is most preferable that the microwave absorbing material is made of a material having the function of radiating far infrared rays. As the far infrared radiating material, the inventor of this invention invented and f iled in Korean Patent Office as Filing Number 91-903, an application disclosing a calcined mixture of magnetic and inorganic materials.

For example, carbonferrite (a compound of carbon powder and ferrite powder in the ratio of 25:75-0. by weight) was mixed with silicon resin or clay in the ratio of 30:70% by weight. The mixture of 2 mm thickness was provided on the upper surface of the oven tray. A microwave oven having the oven tray put therein operated for 3 minutes. A temperature of 1200C was generated. In the other instance, ferrite and cordierrite were mixed and calcined in the ratio of 30:70% by weight. The mixture of 1.5 mm thickness was provided on the upper surface of the conventional oven tray. During the operation of the oven, a temperature of 1100C was generated.

Figures 2, 3A and 3B show a second embodiment of this invention. The difference from the first embodiment is that the microwave absorbing material 3 is provided on the part of the oven tray 1. That is., the absorbing material designed as protrusions of any configuration is attached on either the upper or underside of the tray 1. The amount of the microwave absorbing material is the same as in the first embodiment.

Figures 4, SA and B show a third embodiment of this invention. The difference from the first embodiment is that the microwave absorbing materials are provided on a non-rotatable or removable oven tray. That is, one or more circular or elongate grooves are formed in the tray and the microwave absorbing material 3 is inserted in the groove, with the upper face of the absorbing material 3 being level with or above the upper f ace of the tray 1. The absorbing material may be provided on both sides or the one side of the tray 3 and the amount of the absorbing material is the same as in the first example.

Figure 6 is a sectional view of a fourth embodiment of this invention. When making a rotary or removable oven tray of glass or ceramic material, the microwave absorbing material as in the first embodiment is mixed with the glass or ceramic material and calcined. In this embodiment, the mixture of ferrite and cordierrite in the ratio of 25:75% by weight was utilized and a temperature of 1300C was generated.

6 Figures 7 and 8 show a f ifth embodiment of this invention. The difference from the first embodiment is that holes, which can be of any configuration, are bored in the oven tray, particularly in the rotary oven tray and microwave absorbing materials are inserted through the holes.

It is realized that other modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications as fall within the true spirit and scope of the invention.

f 7

Claims

A microwave oven tray for use in a microwave heating oven having a microwave absorber incorporated therein.
2. A microwave oven tray according to Claim 1, wherein the -microwave absorber is provided in or on at least one surface of the oven tray.
3. A microwave oven tray according to Claim 1, wherein the microwave absorber is provided in or on at least part of the oven tray.
4. A microwave oven tray according to any preceding claim, wherein the microwave absorber defines protrusions.
5. A microwave oven tray according to any of Claims 1 to 3, wherein the microwave absorber is level with the remaining surface of the oven tray.
6. A microwave oven tray according to any preceding claim, wherein the microwave absorber has a function of generating heat.
7. A microwave oven tray according to Claim 6, wherein the microwave absorber radiates far infrared rays when exposed to microwave energy.
8. A microwave oven tray according to any preceding claim, wherein the oven tray has bores formed 8 therein.
9. A microwave oven tray for use in a microwave heating oven, the oven tray being made by mixing glass or ceramic material with a microwave absorbing material and being moulded as a tray shape and then being calcined.
10. A microwave oven tray substantially as specifically described herein with reference to Figures 1, 2, 3(A), 3(B), 4, 5(A), 5(B), 6or7 and8 of the accompanying drawings.