GB2189118A - Heater assembly - Google Patents
Heater assembly Download PDFInfo
- Publication number
- GB2189118A GB2189118A GB08607036A GB8607036A GB2189118A GB 2189118 A GB2189118 A GB 2189118A GB 08607036 A GB08607036 A GB 08607036A GB 8607036 A GB8607036 A GB 8607036A GB 2189118 A GB2189118 A GB 2189118A
- Authority
- GB
- United Kingdom
- Prior art keywords
- assembly
- heater
- elements
- grill
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000000712 assembly Effects 0.000 claims description 13
- 238000000429 assembly Methods 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 5
- 206010052428 Wound Diseases 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 4
- 239000005350 fused silica glass Substances 0.000 claims description 3
- 239000002241 glass-ceramic Substances 0.000 claims description 3
- 229910010293 ceramic material Inorganic materials 0.000 claims description 2
- 239000011810 insulating material Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 claims 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 8
- 239000000377 silicon dioxide Substances 0.000 abstract description 3
- 230000001419 dependent effect Effects 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 210000003298 dental enamel Anatomy 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910001293 incoloy Inorganic materials 0.000 description 1
- 229910001026 inconel Inorganic materials 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000037 vitreous enamel Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/40—Heating elements having the shape of rods or tubes
Landscapes
- Electric Stoves And Ranges (AREA)
Abstract
A heater assembly comprises a silica tube 2 having an inner element 3 and an outer element 4, the inner and outer elements having different heat-up times, the elements being energised together and the fast heat-up element de-energised after a predetermined interval. The assembly can be used in a grill or hotplate arrangement. <IMAGE>
Description
SPECIFICATION
Heater assemblies
This invention relates to heater assemblies and is especially applicable to, although not exclusively so, to heater assemblies for use as grill heater assemblies and hotplate heater assemblies in electric cookers.
In electric cookers it is usual to use metallic sheathed heater elements for the grill and/or hotplate elements. A conventional metallic sheathed element consists of an outer metallic sheath usually made from
Incoloy or Inconel with a spiral heater element down the centre of the tube, the heater element being insulated from the side ofthe tube by an insulating powder, usually Manganese Oxide. The main disadvantage with this type of element is that due to its large thermal inertia e.g. ofthe metal sheath and ofthe insulating powder, it requires a long pre-heatingtime to reach operating temperature.
It is an object ofthe present invention to provide a heater assembly which reduces this pre-heating time, and which thereby achieves an energy saving over conventional heater elements.
According to one aspect ofthe present invention there is provided a heaterassemblycomprising a tubular insulating support having a first heater ele ment through the centre thereof and a second heater element on the outside thereof.
In carrying out the invention according to the aforesaid first aspect, it may be arranged thatthe insulating support is made of a glass based insullating material such as a vitrous silica glass or a glass ceramic or a ceramic material, and the first and second heater elements maytake the form of open wound spiral elements.
In a preferred arrangement for carrying out the aforesaid first aspect of the invention, it will be arranged that one of said heater elements has a substantiallyfaster heat-u p time than the other of said heater elements, it preferably being arranged that the first heater element has a faster heat-up time than the second heater element. It preferably also being arranged that both heater elements are energised together and the fast heat-up element is de-energised after a predetermined interval which may be dependent upon time ortemperature.
The heater assembly according to the aforesaid first aspect may be shaped to any paricular requirement, for example, it may be straight, 'U' shaped, 'C' shaped, looped, zig-zagged etc., and a plurality of such assemblies may be coupled together, either in series, in parallel orin series/parallel.
In the case of a heater assembly being used as a grill element in an electric cooker, it may be disposed between the reflecting surface of a reflector and a safety guard.
According to another aspect of the present inven tion there is provided a heater assembly comprising first and second heater elements, one of said heater elements having a substantially faster heat-up time than the other of said elements, it preferably being arranged that both heater elements are energised together and the fast heat-up element is de-energised after a pre-determined interval which may be dependent upon time ortemperature.
By way of example an exemplary embodiment of the invention will now be described, reference being made toe accompanying drawings, in which:
Fig. lisa section through a grill incorporating a heater assembly according to the present invention;
Fig. 2 is a plan view ofthe grill of Figure 1; and
Fig. 3 is a schematic diagram of a control arrangementforthe grill depicted in Figs. 1 and 2.
ltshould beappreciatedthattheheaterassemblyto be described has very wide application but for the purpose of explaining the principles involved will be described as applied to the grill function of an electric cooker. As well as being applicable to the grill function, a suitable shaped heater assembly in accord ancewiththe present invention may be used in conjunction with one or more ofthe hot-plates of an electric cooker.
The grill shown in Fig. 1 ofthe drawings consists of a heater assembly 1 comprising a vitreous silica glass tube 2 having an inner heater element3 and an an outer heater element 4. The ends ofthe tube 2 are provided with connectors 5 which serveto terminatethe inner and outer heater elements 3 and 4 and also serve to support and secure the tube 2 in position.The grill is also provided with a reflector6 above the heater assembly 1 for reflecting radiant energy downwards onto, say, a grill pan, and a safety guard 7 beneath the heater assembly 1 for preventing access to the heater assembly 1.
The inner and outer heater elements 3 and 4 are conveniently formed as preformed open-wound spiral elements, the inner element 3 being inserted in the tube 2 and the outer element 4 having the tube 2 inserted into it. The silica glass tube 2 may be transparent, translucent or opaque in appearance, and may take any convenient shape dependent upon the particular application. It is envisaged thatthe tube 2 may be straight, 'U' shaped, 'C' shaped, looped, zig-zagged, etc., in order to provide a required heating pattern and it is envisaged that the heater assembly described may be used singly or a plurality of such assemblies may be coupled together either in series, in parallel, or in some series/parallel configuration.In
Fig. 2 an arrangement of N straight heater assemblies is depicted. The connectors 5 terminating the ends of the tube 2 may be individual connectors for a single tube or maytake the form of a multi-way connectorfor terminating a plurality of such tubes.
In operation of the heater assembly described with reference to Fig. 1, it is arranged that the inner heater element3 is used as a booster element that has a faster heating characteristicthan the outer heater element 4, itsfunction being to provide a visible glow within a very short time from it being switched ON and also to pre-heatthe silica tube 2 and the outer element 4. To achieve this the inner element is constructed of a resisitance wire having a suitable coefficient of resistance and watts density to produce the desired
rapid response. It is arranged that the outer element 4, provides the actual grilling function, this being supported bythetub62 which helps prevent the element 4from falling, should itfracture during use or should it collapse.
When the grill of Fig. 1 is switched ON it is arranged that both the inner and outer elements 3 and 4 are energised.The innerelement3 heats rapidlyto give the desired visible glow and to heat the tube 2 and outerelement4. After a period of 30 to 60 seconds, it is arranged that the inner element 3 is de-energised
and remains so during the remainder of the grilling
operation. The ratings ofthe inner and outer elements 3 and 4 and the time period the inner (booster) element3 is energised are chosen so thatthere is minimal change in brightness when the inner element 3 is de-energised.
Control oftheoutereiement4 maybe effected in the normal way by duty cycle control as used with conventional tubular steel grill elements. Such a control arrangement is depicted in Fig. 3 ofthe drawings. In this arrangement a conventional energy regulator8 is provided with usual regulator contacts 9 for controlling the operation ofthe outer/grill element 4 of a heater assembly as described and is also provided with an auxiliary switch 10 for controlling the operation ofthe inner/boost eiement 3 of a heater assembly as described. The auxiliary switch 10 is connected in series with the heaterwinding 11 of a thermal relay 12, the thermal relay 12 having a pair of normally closed contacts 13which are connected in series with the inner/boost element4.The operation ofthecontrolarrangementis as follows:
When the grill control is switched ON,the regulator contacts9 and the auxiliary switch 10 both close to energisethe inner and outer elements 3 and 4. The thermal relay 12 begins to heat up and after 30-60 seconds the thermal relay NC contacts 13 open, thereby switching the inner/boost element 3 OFF. This element remains OFFthroughoutthe remainderofthe grilling function due to the thermal relay being held ON. The outer/grill element4 is switched ON and OFF bytheregulatorcontacts9in conjunction with the
regulator heater 14 and dependent upon the setting
(not shown) ofthe energy regulator8.
In the control arrangement thus far described, when the energy regulator is turned to a relatively low setting, it happens that the visible glow ofthe outer/grill element 4, which is being turned ON and
OFF in accordance with the set duty cycle ofthe energy regulator8, is reduced.This can be off-set by arranging thatthe inner/boost element is turned ON forthe periodthattheouter-grill element4 is turned off. Thus the inner and outer elements will cycle alternately, thereby maintaining the visible g low of the grill.
The detailed construction ofthe grill described with reference to Fig. 1 may take many forms. For example, the reflector may typically be constructed of metal finished in vitreous enamel. Furthermore, the enamel could be catalyticforself-cleaning purposes. It is possible that an insulating material could be provided on top ofthe reflector to prevent excessive temperatures above the grill. Alternatively, the reflector 6 could be made of a ceramic body e.g. porcelain, which could be designed to support the silica tubes and could contain suitableterminationsforthe heater assembly or assemblies. Instead of using ceramic, the reflector6 may be constructed ofceramicfibre or moulded powder which again could support the heater assemblies and could be provided with the necessary reflective properties.In such constructions it may be arranged that any supportsforthe heater assemblies could be designed to provide focussing of the radiant energy onto, say a grill pan positioned below the grill.
The safety guard 7 below the heater assembly may take the form of an open wire mesh or perforated metal orit maytaketheform of a ceramic, glass ceramicorglass plate.
Although in the embodiment described the inner heater element 3 is specified as the booster element, it should be appreciated thatthe outer element4 could be used as the booster element instead.
Additionally, although in the embodiment described the two heater elements are disposed one inside the tube 2 and the other on the outside ofthe tube2, in some arrangements it maybe preferablefor both elements to be either inside a tube or both carried on the outside of a suitable support, the elements being perhaps in side-by-side reiationship or perhaps being inter-spaced.
Claims (13)
1. A heater assembly comprising a tubular insulating support having a first heater element through the centrethereofand a second heaterelementonthe outside thereof.
2. An assembly as claimed in Claim 1, in which the insulating support is made of a glass based ceramic material.
3. An assembly as claimed in Claim 2, in which said material is vitreous silica glass.
4. An assembly as claimed in Claim 2, in which said material is a glass ceramic.
5. An assembly as claimed in any preceding claim, in which the first and second heater elements are formed as open wound spiral elements.
6. An assembly as claimed in any preceding claim, in which one of said heater elements has a substantiallyfaster heat-up time than the other of said elements.
7. An assembly as claimed in Claim 6, in which the first heater element has a faster heat-up time than the second heater element.
8. An assemblyasclaimed in Claim6orClaim 7, in which in operation both heater elements are energised together and the fast heat-up element is de-energisedafterapredetermined interval.
9. An assembly as claimed in any preceding claim, in which the insulating support is shaped to afford a particular heating pattern.
10. Aheater assembly comprising a pluralityof heater assemblies as claimed in any preceding claim, interconnected to provide a required heating pattern.
11. An assembly as claimed in any preceding claim in the form of a grill element.
12. An assembly as claimed in Claim 11 in which the grill element comprises a heater assemblydis- posed between the reflecting surface of a reflector and a safety guard.
13. A heater assembly in the form of a grill substantially as hereinbefore described with reference to the accompanying drawings.
13. A heater assembly comprising first and second heater elements, one of said heater elements having a substantially faster heat-up time than the other of said elements.
14. An assembly as claimed in Claim 13, in which both heater elements are energised together and the fast heat-up element is de-energised after a predetermined interval.
15. A heaterassembly substantially as hereinbe- fore described with reference to the accompanying drawings.
16. Aheaterassembly in the form of a grill substantially as hereinbefore described with refer ence to the accompanying drawings.
Amendments to the claims have been filed, and have thefoilowing effect:
Claims 1-16 above have been deleted or textually amended.
New ortextually amended claims have been filed as follows:
CLAIMS:
1. A heater assembly comprising a tubular insulating support having a first heater element through the centre thereof and a second heater element on the outside thereof, and in which one of said heater elements has a substantially faster heat-up time than the other of said elements.
2. An assembly as claimed in Claim 1, in which the first heater element has a faster heat-up time than the second heater element.
3. An assembly as claimed in Claim 1 or Claim 2, in which in operation both heater elements are energised together and thefast heat-up element is de-energised after a predetermined interval.
4. An assembly as claimed in any preceding claim, in which the first and second heater elements are formed as open wound spiral elements.
5. An assembly as claimed in any preceding claim, in which the insulating support is made of a glass based insulating material.
6. An assembly as claimed in Claim 5, in which said material is vitreous silica glass.
7. An assembly as claimed in Claim 5, in which said material is a glass ceramic.
8. An assembly as claimed in any preceding claim, in which the insulating support is shaped to afford a particular heating pattern.
9. A heater assembly comprising a plurality of heater assemblies as claimed in any preceding claim, interconnected to provide a required heating pattern.
10. An assembly as claimed in any preceding claim in the form of a grill element.
11. An assembly as claimed in Claim 10, in which the grill element comprises a heater assembly disposed between the reflecting surface of a reflector and a safety guard.
12. A heater assembly substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8607036A GB2189118B (en) | 1986-03-21 | 1986-03-21 | Heater assemblies |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8607036A GB2189118B (en) | 1986-03-21 | 1986-03-21 | Heater assemblies |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8607036D0 GB8607036D0 (en) | 1986-04-30 |
| GB2189118A true GB2189118A (en) | 1987-10-14 |
| GB2189118B GB2189118B (en) | 1989-11-22 |
Family
ID=10595010
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8607036A Expired GB2189118B (en) | 1986-03-21 | 1986-03-21 | Heater assemblies |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2189118B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2327328A (en) * | 1997-07-12 | 1999-01-20 | Creda Ltd | Heating element for a grill |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB799547A (en) * | 1955-10-25 | 1958-08-13 | Andrew George Heron | Improvements in electrically heated flexible hoses |
| GB841334A (en) * | 1957-05-03 | 1960-07-13 | Montedison Spa | Metallized fluorocarbon resin |
| GB1275977A (en) * | 1969-08-06 | 1972-06-01 | G J C Dev Ltd | Improvements in electric heating elements and heater assemblies incorporating such elements |
-
1986
- 1986-03-21 GB GB8607036A patent/GB2189118B/en not_active Expired
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB799547A (en) * | 1955-10-25 | 1958-08-13 | Andrew George Heron | Improvements in electrically heated flexible hoses |
| GB841334A (en) * | 1957-05-03 | 1960-07-13 | Montedison Spa | Metallized fluorocarbon resin |
| GB1275977A (en) * | 1969-08-06 | 1972-06-01 | G J C Dev Ltd | Improvements in electric heating elements and heater assemblies incorporating such elements |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2327328A (en) * | 1997-07-12 | 1999-01-20 | Creda Ltd | Heating element for a grill |
| GB2327328B (en) * | 1997-07-12 | 2001-07-25 | Creda Ltd | Heating element for a grill |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2189118B (en) | 1989-11-22 |
| GB8607036D0 (en) | 1986-04-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20010321 |