WO2002037898A1

WO2002037898A1 - Electric heater assembly

Info

Publication number: WO2002037898A1
Application number: PCT/GB2001/004796
Authority: WO
Inventors: Gavin John Coleman
Original assignee: Ceramaspeed Ltd
Current assignee: Ceramaspeed Ltd
Priority date: 2000-11-04
Filing date: 2001-10-30
Publication date: 2002-05-10
Anticipated expiration: 2003-05-04
Also published as: GB2384153B; GB0026991D0; AU2002210737A1; GB0309362D0; JP3903256B2; JP2004513491A; GB2384153A

Abstract

An electric heater assembly (2) includes a support plate (4) comprising at least one dish-like recess (10) surrounded by a substantially planar region (5) having front and rear faces (6, 8), the dish-like recess being open at the front face (6) of the planar region. The at least one dish-like recess (10) has a base (12) and a peripheral wall (14) extending between the base and the planar region (5). A layer (16) of thermal and electrical insulation material is provided in the at least one dish-like recess (10), with at least one electrical heating element (20) supported relative thereto. A terminal arrangement (22), electrically connected to the at least one heating element (20) is located in an aperture (26) provided in the peripheral wall (14) of the at least one dish-like recess (10), whereby at least one electrically conductive terminal is (24) incorporated in the terminal arrangement (22) and is accessible at the rear face (8) of the substantially planar region (5) of the plate (4).

Description

ELECTRIC HEATER ASSEMBLY

The present invention relates to an electric heater assembly and more particularly, but not exclusively, relates to a radiant electric heater assembly such as for use in a cooking appliance, which may be an oven or hob.

It is known to provide an electric heater assembly in which a relatively large support plate, such as of sheet metal, has one or more dish-like recesses formed therein. Each of the one or more dish-like recesses is known to be provided therein with a layer of thermal and electrical insulation material supporting at least one radiant electric heating element.

It is known to provide such an assembly, with multiple dish-like recesses and heating elements, for use under a glass-ceramic surface of a cooking hob. An arrangement of this nature obviates the need for multiple separate individual heaters each with its own individual support dish.

It is necessary to provide electrical wiring to the heating element or elements in each dish-like recess and this has hitherto been effected such as by providing channels in an upper or front surface of the support plate, which is inconvenient.

Furthermore, there is also a requirement for an electric heater assembly of this nature for use in an oven, which may be a microwave oven and where a support plate incorporating one or more dish-like recesses with one or more heating elements may be required to form part of a wall, or a complete wall, of a cavity of the oven. In such an application, the provision of electrical wiring on the front surface of the support plate cannot be considered because such wiring would be subject to the hot and hostile environment of the oven cavity.

It is an object of the present invention to overcome or minimise this problem.

According to the present invention there is provided an electric heater assembly comprising:

a support plate comprising at least one dish-like recess surrounded by a substantially planar region having front and rear faces, the dish-like recess being open at the front face of the planar region and having a base and a peripheral wall extending between the base and the planar region; a layer of thermal and electrical insulation material provided in the at least one dish-like recess, with at least one electric heating element supported relative thereto; and

a terminal arrangement electrically connected to the at least one heating element and located in an aperture provided in the peripheral wall of the at least one dishlike recess, whereby at least one electrically conductive terminal is incorporated in the terminal arrangement and is accessible at the rear face of the substantially planar region of the plate.

The terminal arrangement may comprise a terminal block, such as comprising electrically insulating material, incorporating the at least one electrically conductive terminal.

The terminal block may be secured in the aperture provided in the peripheral wall of the at least one dishlike recess. The terminal block may be slotted into the aperture in the peripheral wall.

The aperture in the peripheral wall of the at least one dish-like recess may extend to the front face of the plate and may extend laterally from the at least one dish-like recess into an adjacent region of the substantially planar region of the plate.

The at least one dish-like recess may be provided integrally with the support plate and may be moulded or press-formed therein.

The support plate may comprise metal, such as steel.

The layer of thermal and electrical insulation material may cover the.base of the at least one dish-like recess.

The layer of thermal and electrical insulation material may additionally be contoured to provide an integral elevated wall portion against at least part of the peripheral wall of the at least one dish-like recess.

Alternatively, a separate wall portion of thermal and electrical insulation material may be provided against at least part of the peripheral wall of the at least one dish-like recess.

The peripheral wall of the at least one dish-like recess may be of stepped form. The layer of thermal and electrical insulation material may comprise microporous thermal and electrical insulation material.

The at least one electric heating element may be a radiant heating element and may be selected from wire, metal ribbon, metal foil, and lamp elements. In particular, the at least one electric heating element may comprise a corrugated metal ribbon supported edgewise on the layer of thermal and electrical insulation material.

A plurality of dish-like recesses may be provided in the support plate.

The support plate may be adapted to form at least part of a wall of a cavity of an oven, or may be adapted to form at least part of a base component for underlying a hotplate, such as a glass-ceramic cooking surface.

The terminal arrangement of the heater assembly of the present invention obviates the need to provide electrical wiring on the front face of the support plate. All necessary wiring is conveniently provided to the terminal arrangement at the rear of the plate. Because the terminal arrangement is provided at the peripheral wall of the at least one dish-like recess, it can be maintained substantially within the depth of the at least one dish-like recess, as can the wiring connected thereto. This minimises the clearance required to be provided at the rear of the support plate when the heater assembly is installed in its intended application.

For a better understanding of the invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

Figure 1 is a front view of an embodiment of electric heater assembly according to the present invention;

Figure 2 is a rear view of the assembly of Figure 1; and

Figure 3 is a schematic front view of a further embodiment of electric heater assembly according to the present invention.

Referring to Figures 1 and 2, an electric heater assembly 2 comprises a sheet metal support plate 4, such as of steel, having a substantially planar region 5 with a front face 6 and a rear face 8. The plate 4 has an integral dish-like recess 10 provided by a conventional moulding or press-forming technique. The dish-like recess 10 is open at the front face 6 of the substantially planar region 5 of the plate 4 and has a base 12 and a peripheral wall 14, which can be of stepped form and which extends between the base 12 and the substantially planar region 5 of the plate 4.

A layer 16 of thermal and electrical insulation material, such as well-known microporous thermal and electrical insulation material, is provided inside the dish-like recess 10 and covering the base 12. The layer 16 of insulation material is contoured to provide an integral elevated wall portion 18 against the inside of the peripheral wall 14 of the dish-like recess 10.

Instead of the elevated wall portion 18 of insulation material being provided as an integral part of the layer 16, it could be provided as a separate wall portion located against the inside of the peripheral wall 14 of the dish-like recess 10. Such a separate wall portion could be provided of the same material as the layer 16 covering the base, or of a different material.

At least one radiant electric heating element 20 is supported relative to (i.e. is supported in, on or above) the layer 16 of insulation material in the dish-like recess 10. Such heating element or elements 20 can comprise any of the well-known forms of element, such as wire, metal ribbon, metal foil, or lamp elements. In particular, the heating element or elements 20 can comprise a corrugated metal ribbon supported edgewise on the layer 16 of insulation material.

A terminal block 22, formed of electrically insulating material and incorporating electrically conductive terminals 24, is secured in an aperture 26 provided in the peripheral wall 14 and such that the terminals 24 extend laterally therefrom and are accessible at the rear face 8 of the substantially planar region 5 of the support plate 4. The terminals 24 in the terminal block 22 are electrically connected to the heating element or elements 20. An aperture is also provided in the wall portion 18 of insulation material to accommodate the terminal block 22.

The aperture 26 in the peripheral wall 14 is arranged to extend to the front face 6 of the substantially planar region 5 of the plate 4 and also extends laterally from the dish-like recess 10 into an adjacent region 28 of the plate 4. This enables the terminal block 22 to be slotted into, and secured in, the aperture 26 in the peripheral wall 14. Electrical wiring (not shown) is connected to the terminals 24 at the rear of the plate 4 for providing energising voltage from a supply (not shown) to the heating element or elements 20.

The terminal block 22 is maintained substantially within the depth of the dish-like recess 10, since it is located in the peripheral wall 14. The external wiring, connected to the terminal block, is all provided at the rear of the plate 4 and can likewise be maintained within the depth of the recess 10. This minimises the clearance which is required to be provided at the rear of the support plate 4 when the heater assembly is installed in its intended application.

As shown in Figure 3, a heater assembly 2 can also be provided in which a plurality of dish-like recesses 10 are provided containing the same arrangement of heating element or elements 20, insulation layer 16 and terminal arrangement 22, 24 as shown in Figures 1 and 2.

The support plate 4 may be adapted to form at least part of a wall of a cavity of an oven, which may be a microwave oven, which cavity is to be heated by the heating element or elements 20. Wiring to the heating element or elements 20 can therefore be hidden behind the wall of the oven cavity.

Alternatively, the support plate 4 may be adapted to form at least part of a base component for underlying a hotplate, such as a glass-ceramic cooking surface, with electrical wiring to the heating element or elements 20 being located at a rear surface thereof.

Claims

1. An electric heater assembly characterised by:

a support plate (4) comprising at least one dish-like recess (10) surrounded by a substantially planar region (5) having front and rear faces (6 and 8, respectively), the dish-like recess being open at the front face of the planar region and having a base (12) and a peripheral wall (14) extending between the base and the planar region;

a layer (16) of thermal and electrical insulation material provided in the at least one dish-like recess (10) , with at least one electric heating element (20) supported relative thereto; and

a terminal arrangement (22) electrically connected to the at least one heating element (20) and located in an aperture (26) provided in the peripheral wall (14) of the at least one dish-like recess (10) , whereby at least one electrically conductive terminal (24) is incorporated in the terminal arrangement and is accessible at the rear face (8) of the substantially planar region (5) of the plate (4) .

2. An assembly as claimed in claim 1, characterised in that the terminal arrangement (22) comprises a terminal block, for example of electrically insulating material, incorporating at least one electrically conductive terminal (24) .

3. An assembly as claimed in claim 2, characterised in that the terminal block (22) is secured in the aperture (26) provided in the peripheral wall (14) of the at least one dish-like recess (10) , securing being effected for example by slotting into the aperture.

4. An assembly as claimed in any preceding claim, characterised in that the aperture (26) in the peripheral wall (14) of the at least one dish-like recess (10) extends to the front face (6) of the substantially planar region (5) of the plate (4), the aperture (26) optionally extending laterally from the at least one dish-like recess (1) into an adjacent region of the substantially planar region (5) of the plate (4) .

5. An assembly as claimed in any preceding claim, characterised in that the at least one dish-like recess (10) is provided integrally with the support plate (4), for example by being moulded or press-formed in the plate.

6. An assembly as claimed in any preceding claim, characterised in that the support plate (4) comprises metal, such as steel.

7. An assembly as claimed in any preceding claim, characterised in that the layer (16) of thermal and electrical insulation material covers the base (12) of the at least one dish-like recess (10) .

8. An assembly as claimed in claim 7, characterised in that the layer (16) of thermal and electrical insulation material is additionally contoured to provide an integral elevated wall portion (18) against at least part of the peripheral wall (14) of the at least one dish-like recess (10) .

9. An assembly as claimed in claim 7, characterised in that a separate wall portion of thermal and electrical insulation material is provided against at least part of the peripheral wall (14) of the at least one dish-like recess (10) .

10. An assembly as claimed in any preceding claim, characterised in that the peripheral wall (14) of the at least one dish-like recess (10) is of stepped form.

11. An assembly as claimed in any preceding claim, characterised in that the layer (16) of thermal and electrical insulation material comprises microporous thermal and electrical insulation material.

12. An assembly as claimed in any preceding claim, characterised in that the at least one electric heating element (20) is a radiant heating element, for example selected from wire, metal ribbon, metal foil, and lamp elements.

13. An assembly as claimed in claim 12, characterised in that the at least one electric heating element (20) comprises a corrugated metal ribbon supported edgewise on the layer (16) of thermal and electrical insulation material .

14. An assembly as claimed in any preceding claim, characterised in that a plurality of dish-like recesses (10) are provided in the support plate (4) .