GB2333679A

GB2333679A - Protection grid support in a radiant electric heater

Info

Publication number: GB2333679A
Application number: GB9801241A
Authority: GB
Inventors: Peter Ravenscroft Wilkins
Original assignee: Ceramaspeed Ltd
Current assignee: Ceramaspeed Ltd
Priority date: 1998-01-22
Filing date: 1998-01-22
Publication date: 1999-07-28
Anticipated expiration: 2018-01-22
Also published as: GB9801241D0; EP0932326A3; GB2333679B; EP0932326A2

Abstract

A radiant electric heater comprises a dish-like support (1) containing a base layer (2) of thermal and electrical insulation material and has supported therein one or more radiant electric heating elements (3). A metal grid or mesh means (6) is provided overlying the heater and spaced from the one or more heating elements. At least one spacer means (7) is provided inside the dish-like support (1) and cooperates between the metal grid or mesh means (6) and the dish-like support (1) and/or the base layer (2) of insulation material.

Description

1 Radiant Electric Heater 2333679 This invention relates to radiant

electric heaters, particularly-, but not exclusively,, for use in cooking appliances.

Radiant electric heaters are well known comprising a dish-like support containing thermal and electrical insulation material and having supported therein one or more radiant electric heating elements. In a well known construction, a metal dish-like support has therein a base lay, er of insulation material. such as microporous thermal and electrical insulation material and one or more radiant heating elements, such as of wire or ribbon form are supported on the base layer.

A wall of insulation material is also known to be provided around the periphery of the dish-like support, such wall being separate from, or integral with. the base layer.

It is well known to use such radiant heaters behind a sheet of glassceramic material, particularly in cooking appliances. However there are applications, such as in deep fat fr3,ers, where the use of a sheet of glass-ceramic material is not required but.%, here some form of protection against mechanical damage is required for the heater. In this regard it has been proposed to provide a metal grid or mesh overlying the heater and spaced from the heating element or elements. Such grid or mesh suitably contacts the upper surface of the peripheral wall of the heater.

A problem has arisen with such an arrangement in that during use of the heater sagging of the grid or mesh can occur, to the extent that there is a risk of it contacting the heating element or elements. which is unacceptably dangerous.

2 It is an object of the present invention to overcome this disadvantage.

The present invention provides a radiant electric heater comprising a dish-like support containing a base layer of thermal and electrical insulation material and having supported therein one or more radiant electric heating elements, a metal grid or mesh means being arranged to be provided overlying the heater and spaced from the one or more heating elements, at least one spacer means being provided inside the dish-like support and cooperating between the metal grid or mesh means and the dish-like support and/or the base layer of insulation material.

The at least one spacer means may contact, or be secured in, the base layer of insulation material and/or may contact or be secured to the dishlike support.

The at least one spacer means may contact, and be optionally secured to, the metal grid or mesh means.

The at least one spacer means may be moulded into the base layer of insulation material, which may comprise nucroporous thermal and electrical insulation material. Such microporous insulation material may be moulded into the dish-like support and the at least one spacer means 20 ma-,r- be simultaneously moulded into the base layer.

The at least one spacer means may comprise at least one boss, peg or pillar, such as of ceramic or metal.

A single spacer means may be provided, located substantially in a central region of the heater, 3 The dish-like support may, have a peripheral wall, the metal grid or mesh means being arranged to be provided in a plane defined substantially, byl an upper surface of the wall.

The peripheral wall may. be provided of thermal insulation material and may be separate from, or integral with, the base laver of insulation material.

1 The one or more heating elements may be of wire, ribbon or lamp form, or combinations thereof.

The dish-like support may comprise a metal.

The invention is now described by way of example with reference to the acconipany.ing drawings in which:

Figure 1 is a plan view of a radiant electric heater according to the invention; and Figure 2 is a cross section through the heater of Figure 1.

A radiant electric heater is constructed for use, for example, in a cooking appliance such as the base of a deep fat fry.er. The heater comprises a metal dish-like support 1 containing a base laver 2 of microporous thermal and electrical insulation material. One or more radiant electrical heating elements 3 is or are provided in the dish-like support 1. As shown. a heating element comprises a metal ribbon secured edgewise on the surface of tile base laver 2. 25 Hoss-ever other forms of heating element could be considered. such as coiled wire or lamp 4 elements. Combinations of elements could be provided. A terminal block 4 is provided at the edge of the heater for connecting the heating element or elements 3 to a voltage supply.

A peripheral wall 5 of thermal insulation material of well known form is provided at the edge of the heater. The peripheral wall 5 is shown as separate from the base layer 2, but could be provided integral therewith.

The heater is arranged for operation behind or beneath a protective metal grid or mesh means 6 which is arranged to overlie the top surface of the peripheral wall 5, or at least in a plane 10 defined substantially by the top surface of the peripheral wall.

There is a risk that, during operation of the heater, the metal grid or mesh means 6 may sag and contact, or approach undesirably close to, the heating element or elements 3. This is dangerous and must be avoided.

To prevent such sagging of the metal grid or mesh means 6, at least one spacer means 7 is provided cooperating between the metal grid or mesh means 6 and the base layer 2. As shown in the accompanying drawings, a single spacer means 7 is provided located substantially in a central region of the heater. However a plurality of spacer means could be provided if desired.

The spacer means 7 comprises an upstanding boss, peg or pillar, preferably of ceramic although it could be of metal.

The spacer means 7 is secured in the base layer 2 and contacts, and is optionally secured to.

3 the metal grid or mesh means 6, thereby preventing the latter from sagging during operation of the heater.

The base layer 2 of microporous insulation material may be formed by moulding particulate microporous insulation material into the metal dish I and the spacer means 7 may be advantageously simultaneously moulded into the base laver 2, that is, it is co-moulded with the base layer 2.

The spacer means 7 may be arranged to contact, and optionally be secured to, the base of the metal dish-like support 1, as shown by the dotted outline 7A in Figure 2. In such a case, tight securement in the base layer 2 is not required.

The spacer means 7 may optionally be secured to the metal grid or mesh means 6 and arranged to contact the surface of the base layer 2.

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Claims

Clairns

1. A radiant electric heater comprising a dish-like support containing a base layer of thermal and electrical insulation material and having supported therein one or more radiant electric heating elements, a metal grid or mesh means being arranged to be provided overlying the I heater and spaced from the one or more heating elements, at least one spacer means being provided inside the dish-like support and cooperating between the metal grid or mesh means and the dish-like support and/or the base layer of insulation material.

2. A heater according to claim 1, in which the at least one spacer rneans contacts, or is secured in, the base layer of insulation material and/or contacts or is secured to the dishlike support.

3. A heater according to claim I or 2, in which the at least one spacer means contacts, and is optionally secured to, the metal grid or mesh means.

4.

A heater according to claim 1, 2 or 3, in which the at least one spacer means is moulded into the base layer of insulation material.

5. A heater according to claim 4, in which the base layer comprises microporous thermal and electrical insulation material.

6. A heater according to claim 5, in which the microporous thermal and electrical insulation material is moulded into the dish-like support and the at least one spacer means is 25 simultaneoushl moulded into the base laver.

7 7. A heater according to any preceding claim, in which the at least one spacer illearis comprises at least one boss, peg or pillar.

8. A heater according to claim 7, in which the at least one boss. peg or pillar comprises ceramic or metal.

9, A heater according to any preceding claim, in which a single spacer means is provided, located substantially in a central region of the heater.

10. A heater according to any preceding claim, in which the dish-like support has a peripheral wall, the metal grid or mesh means being arranged to be provided in a plane defined substantially by an upper surface of the wall.

11. A heater according to claim 10, in.ihich the peripheral wall is provided of thermal insulation material and is separate from, or integral with, the base layer of insulation material.

12. A heater according to any preceding claim, in which the one or more heating elements is or are of wire, ribbon or lamp form, or combinations thereof

13. A heater according to any, preceding claim, in which the dish-like support comprises a metal.

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14. A radiant electric heater constructed and arranged substantially, as hereinbefore described with reference to the accompanying drawings.