WO2002007575A1

WO2002007575A1 - Improvements relating to electrically heated vessels

Info

Publication number: WO2002007575A1
Application number: PCT/GB2001/002933
Authority: WO
Inventors: Robert Andrew O'neill; Antonio Martin Gaeta; Peter Hallam Wright
Original assignee: Otter Controls Limited
Priority date: 2000-07-25
Filing date: 2001-07-02
Publication date: 2002-01-31
Also published as: AU2001266224A1; GB0018245D0; GB2364890A

Abstract

A liquid heating jug having a glass jug body is fitted with a planar electric heating element by providing a bulge just above the open bottom of the jug body, providing a hub base part which fits over the top of the jug body and engages with the bulge, juxtaposing the heating element with the open bottom of the glass body with a seal provided therebetween, and securing the heating element in place by use of base closure member which is secured to the base part and has support features which hold the heating element in place.

Description

IMPROVEMENTS RELATING TO ELECTRICALLY

HEATED VESSELS

Field of the Invention:

This invention concerns improvements relating to electrically heated

vessels, particularly electrically powered liquid heating vessels such as kettles,

hot water jugs, pots, pans, urns, laboratory equipment and the like. More

particularly, the invention concerns improvements relating to the assembly of

planar electric heating elements into the bodies of such vessels.

Background of the Invention;

Planar heating elements as used in liquid heating vessels as

abovementioned are commonly of two different types, namely the underfloor

type which comprises a metal plate having a sheathed heating element

clamped or clenched to the underside thereof and the thick film type which

comprises a resistance heating track or layer formed on the underside of an

electrically insulating substrate, commonly a stainless steel plate provided

with a glass insulating layer. Such planar heating elements give rise to

particular problems as regards their assembly into the bodies of liquid heating

vessels and there have been many proposals for effecting such assembly. hi GB-A-2 315 204 for example a planar heating element is secured

into an aperture in the bottom of a vessel by provision of a flange surrounding

such aperture and having a plurality of through holes enabling studs or bolts

on the heating element periphery to be passed through the flange for securing

the heating element to the flange, a gasket seal being provided between the

heating element and the flange.

In GB-A-2 330 064 an alternative proposal has abutments provided

within the vessel body and the planar heating element is urged against and

retained relative to such abutments by means of a circlip arrangement which

interacts with formations provided in the wall of the vessel body, a resilient

seal of elastomeric material being provided around the periphery of the

heating element and providing sealing between the heating element and the

surrounding internal surface of the vessel wall.

A variation of the proposal of GB-A-2 330 064 is the subject of

GB-A-2 344 506 and is concerned particularly with the problems of fixing

planar heating elements into glass bodied vessels which are subject to

dimensional variations greater than those encountered in plastics bodied

vessels. In accordance with the teachings of GB-A-2 344 506, the

arrangement of GB-A-2 330 064 is modified so that the seal acts between the

periphery of the heating element and the external surface of the glass vessel,

rather than the internal surface as in the arrangement taught in

GB-A-2 330 064. Since glass vessels are generally blown and formed in a

mould, their outer dimensions can be fairly accurately controlled, which is not generally the case for their internal dimensions, so that by providing sealing

between the heating element and the vessel exterior a more satisfactory

solution can be achieved.

Notwithstanding the above proposals, problems can still arise in the

assembly of planar heating elements to glass bodied vessels. The proposal of

GB-A-2 315 204 necessitates the provision of holes in a flange in the bottom

of the vessel and this is not a straightforward matter for glass vessels. The

proposal of GB-A-2 344 506 requires the provision of some additional

support means for the heatmg element and this can compromise the styling of

the product. It has been proposed in GB-A-2 344 506 to use adhesive as a

means of securing the assembly, but this is not preferred on account of cost

and curing time considerations.

Proposals for overcoming the abovementioned problems are described

in our British Patent Application No. 0016050.7 filed 29 June 2000.

Objects and Summary of the Invention:

The object of the present invention is to provide yet a further proposal

for overcoming or at least substantially reducing the abovementioned

problems.

According to the present invention, the body of an electrically heated

liquid heating vessel comprises a body part proper with an open bottom to

which a planar heating element is fitted, a base part which encircles the bottom of the body part proper with an outwardly-extending abutment that is

provided around the bottom of the body part proper in abutment with and

beneath an inwardly-extending part of the base part, and a bottom closure

secured to the base part and serving to hold the planar heating element in

place.

Described hereinafter is an exemplary embodiment of the invention in

which the body part proper is formed of glass and has a region of increased

diameter just above a cylindrical sealing region adjacent its open bottom, such

increased diameter region constituting the abovementioned

outwardly-extending abutment. An annular plastics moulding constitutes the

base part and is arranged to be slipped over the top of the glass body part

proper, and this moulding has a mating neck region which fits against the

upper surface of the increased diameter region of the glass body part proper so

that the latter cannot pass through the moulding, this neck region constituting

the abovementioned inwardly-extending part of the base part, ie. the

moulding. The moulding has support features to which the bottom closure is

affixed and the bottom closure in turn has support features which bear against

the underside of the planar heating element and urge the heating element

periphery against the bottom of the glass body part proper. A seal is provided

between the heating element periphery and the glass body part proper, for

example in accordance with the teachings of GB-A-2 344 506

abovementioned, and preferably has a part which extends between the heating element and the glass so as to act as a thermal barrier which has the effect of

reducing thermal stressing of the glass.

The above and further features of the present invention are set forth in

the appended claims and will be more fully explained in the following

description which is given with reference to the accompanying drawings.

Description of the Drawings:

Figure 1 is a cross-sectional showing of an exemplary embodiment of

the present invention;

Figure 2 is an enlarged showing of the part of Figure 1 that is within

the circle C;

Figure 3 is an exploded perspective view showing the component parts

of the embodiment of Figures 1 and 2;

Figure 4 is a cross-sectional showing of another exemplary

embodiment;

Figure 5 is a cross-sectional showing of the glass body part proper of

the embodiment of Figure 4; and

Figure 6 is an enlarged showing of the part of Figure 5 that is within

the circle A.

Detailed Description of the Embodiments: Referring first to Figures 1, 2 and 3, which show a first embodiment, Figure 1 shows a cross section through a simplified assembly, Figure 2 shows an enlargement of the seal and support area of Figure 1, and Figure 3 shows an exploded view of the components. A glass body 1 has a bulge 7 around its lower end, with a parallel section 8 of reduced diameter below the bulge. A cover/support moulding 4 fits over the glass body 1 and has a tapered region 9 which mates with the upper surface 10 of the bulge 7. The glass body 1 is entered into the support moulding 4 from below, and the support moulding sits on the bulge, preventing the glass body from passing right through. A bottom cover component 5 (which may be a plastics moulding or a metal pressing) is fastened to the support moulding 4 by means of suitable fasteners (not shown) which engage with the bores 11. The bottom cover 5 supports the heating element plate 3, either directly via pillars or indirectly through a control 6 which is mounted on the bottom of the element 3. The control 6 might be an X4 control or an X2 with associated mounting brackets, or an X2 and CP7 combination, either the X4 or the X2 and CP7 combination giving a 360° cordless connection. The bottom cover 5 is arranged to press the heating

element 3 against the bottom edge of the glass body 1. A seal 2 is positioned between a vertical flange of the heating element 3 and the lower parallel

section 8 of the glass body, and may also extend between the bottom edge of

the glass body and the horizontal surface of the element so as to act as a heat

shield preventing contact between the heating element and the glass. The seal 2 is shown as having a simple "L" section, but could be of any shape, advantageously the finned "Easifix" shape (everted or otherwise), to

accommodate tolerances of the glass vessel.

The X2 control is available from us and is substantially as described in

GB-A-2 283 156, GB-A-2 306 801, GB-A-2 312 142, GB-A-2 315 366,

GB-A-2 317 544 and GB-A-2 307 602. The X4 control is also available from

us and is substantially as described in WO-A-9954903. The CP7 is a 360°

cordless connector component and, together with its mating CS4 connector, is

available from us and is substantially as described in GB-A-2 285 716.

Easifix seals are the subject of GB-A-2 330 064 and GB-A-2 344 506.

Figures 4 to 6 show views of a more complete embodiment of the

invention. Figure 4 shows a cross section through a jug provided with an

element mounting according to the invention. The jug vessel body 1 ' has a

tapered, curved form. In order for the system to work, the top of the vessel

body must be of smaller diameter than the bulge section, so that it can pass

through the support moulding 4'. In Figure 4 the support moulding is formed

as an integral part of a handle and spout moulding, and means are shown for

clipping the spout part to the upper rim of the glass vessel. Not shown is a

sealing means to prevent drips leaking from between the moulding and the

rim of the vessel. Figure 4 also shows the use of pillars 12 to support the

heating element, rather than by use of a control as in Figure 1. The

construction according to Figure 4 gives a straightforward assembly operation

without need for any special equipment or adhesives, although adhesives

could be used if desired, the moulded seal being replaced with RTV silicone rubber (bath tub sealant) for example. As shown, a steam control 13 may be

mounted in the handle, with the wires being led down a duct formed between

the vessel and the moulding. Alternatively the steam control could be

mounted in the space between the heating element and the bottom cover (a Z5

directly mounted to an X4, for example), which would simplify the support

moulding and the handle form. The handle could, for example, be a single

moulding of a rigid foam filled type to give the desired profile without

multiple mouldings with their additional assembly and fastening requirements.

Figure 5 shows a detail of the glass vessel, with a magnified detail of the

bulge region shown in Figure 6.

Steam controls, as is well known, serve to switch off or reduce the

power supplied to a heating element when water is boiled and steam

generated. The Z5 steam control is available from us and is substantially as

described in GB-A-2 331 848.

The invention having been described in the foregoing by reference to

specific embodiments, it is to be appreciated that the described embodiments

are exemplary only and that modifications and variations could be made

thereto without departure from the spirit and scope of the appended claims.

For example, whereas the described embodiments have concerned glass

bodied vessels, the same teachings could usefully be applied to vessels formed

of other materials such as ceramics (porcelain) or earthenware for example.

Furthermore, whilst the described embodiments have an abutment formed as

an outward bulge extending completely and continuously around the bottom of the vessel body, it would be possible to have a plurality of spaced-apart abutment elements extending discontinuously around the vessel body. Since the abutment (bulge) serves only to prevent the vessel body part from passing

completely through the base part, any form of abutment means that will accomplish this can be employed.

Claims

CLAIMS:

1. An electrically heated vessel having a body which comprises a body

part proper with an open bottom to which a planar heating element is fitted, a

base part which encircles the bottom of the body part proper with an

outwardly-extending abutment that is provided around the bottom of the body

part proper in abutment with and beneath an inwardly-extending part of the

base part, and a bottom closure secured to the base part and serving to hold

the planar heating element in place.

2. A vessel as claimed in claim 1 wherein the vessel body is formed of

glass and has a region of increased diameter adjacent to its open bottom, said

regional constituting said outwardly-extending abutment.

3. A vessel as claimed in claim 2 wherein said base part comprises a

metal or plastics material member which is configured to be able to be placed

over the top of the vessel body and moved down until a

complementarily-shaped region thereof engages said increased diameter

region of the vessel body, said complimentarily-shaped region constituting

said inwardly-extending part of the base part.

4. A vessel as claimed in claim 3 wherein said metal or plastics material

member has support features providing for attachment of the bottom closure

thereto.

5. A vessel as claimed in any of the preceding claims wherein the bottom

closure has support features which bear against the underside of the planar

heating element to hold it in place.

6. A vessel as claimed in any of the preceding claims wherein a seal is

provided between the planar heating element and the open bottom of the

vessel body.

7. A vessel as claimed in claim 6 wherein the vessel body is formed of

glass and the seal is formed so as to constitute a thermal barrier between the

planar heating element and the glass vessel body.

8. An electrically heated liquid heating vessel comprising a vessel body

part having a top and an open bottom, a base part extending around the bottom

of the body part, the base part being configured to be assembled with the body

part by insertion of the top of the body part into the base part and passing the

body part through the base part until abutment means provided on the body

part engages the base part to prevent further insertion, a base closure secured

to the base part, and a planar heating element held in sealing engagement with

the open bottom of the body part by means of the base closure.

9. An electrically heated liquid heating vessel substantially as herein

described with reference to Figures 1 to 3 of the accompanying drawings or

Figures 4 to 6 of the accompanying drawings.

10. A method of assembling a liquid heating vessel, said method

comprising:

(i) forming a vessel body part having a top and an open bottom

and wherein outwardly extending abutment means are provided

around the vessel body at a location above its bottom;

(ii) forming a vessel base part so that the vessel body part can be

inserted therein, top first, until the abutment means on the body

part engage the base part to limit further insertion;

(iii) assembling a planar heating element sealingly with the open

bottom of the vessel body part; and

(iv) securing a base closure member to the base part to hold the

heating element in place.