GB2337194A

GB2337194A - Electric kettle with water level indicator

Info

Publication number: GB2337194A
Application number: GB9810284A
Authority: GB
Inventors: Robert Andrew O'neill; Antonio Martin Gaeta
Original assignee: Otter Controls Ltd
Current assignee: Otter Controls Ltd
Priority date: 1998-05-13
Filing date: 1998-05-13
Publication date: 1999-11-17
Anticipated expiration: 2018-05-13
Also published as: GB9810284D0; GB2337194B

Abstract

An electrically heated water boiling vessel has a body (eg of metal) with a recess 5 accommodating a liquid level indicator in the form of a plastics material moulding 8 which, in addition to having a passageway 11 communicating with the vessel interior for providing an indication of the water level in the vessel, has separate condensation drainage and electrical cable routing passageways 12, 10 extending from end to end of the moulding. A steam sensor control 15 is located in a steam compartment defined in a handle 13 of the vessel and is responsive to steam vented from the vessel interior when water boils therein, the drainage passageway 12 in the liquid level indicator moulding 8 communicates with the steam compartment in the handle, and the cable routing passageway 10 contains electrical conductors connecting the steam sensor 15 to other electrical parts of the vessel that are located at the bottom of the vessel.

Description

2337194 IMPROVEMENTS RELATING TO ELECTRICALLY HEATED WATER BOILING VESSELS

Field of the Invention:

This invention concerns improvements relating to electrically heated water boiling vessels such as, tor example, domestic electric kettles and hot water jugs.

Background of the Invention:

Electrically heated water boiling vessels are known which comprise a vessel for containing water, an electrically powered heating element for heating water contained in the vessel, a heating element overtemperature protection control for switching off the supply of electricity to the heating element in response to a sensed heating element overtemperature condition, caused for example by switching on the appliance without first filling the vessel with water, and a steam sensor control for switching off or reducing the supply of electricity to the heating element in response to the generation of steam when water boils in the vessel.

The problem that arises with such water boiling vessels is to accommodate the various control components within an aesthetically pleasing vessel structure.

2 Early automatic kettles incorporated metal sheathed resistance heating elements located within the vessel for heating the water by immersion heating, a heating element head plate serving to secure the heating element in the vessel and the head plate being secured and sealed into an aperture provided at a low level in the vessel wall. The heating element overtemperature control was located on the rear of the heating element head plate and sensed the heating element temperature through the head plate. The steam sensor control was located at a high level of the vessel, adjacent to a steam vent provided in the vessel wall. The overtemperature and steam sensor controls comprised bimetallic actuators arranged at opposite ends of an elongate lever of an overcentre switch-actuating mechanism and spaced apart from each other by a distance of the order of 10 to 15 cms, and a relatively massive moulded plastics handle moulding was employed to cover the controls. An example of such an arrangement is disclosed in GB-A- 1470 64.

In order to avoid the need for relatively massive handle mouldings to conceal the interconnected steam sensor control and heating element overtemperature control, the steam pipe was invented. This is described in GB-A-1 316 436. Rather than providing a steam vent at an upper part of the vessel, a steam pipe was provided in the vessel, the steam pipe having an upper end, which was open for access of steam at an upper level within the vessel, and extending down through the vessel to where it extended through the heating element head plate, thereby establishing a path for steam from above 3 the level of water boiling in the vessel to a location behind the heating element head plate. This enabled the bimetallic actuators of the heating element overtemperature control and the steam control to be located closely adjacent to each other whereby the overall size of the arrangement could be reduced and its visual impact made more aesthetically pleasing.

Particularly with the advent of plastics bodied water heating jugs, which customarily have a taller and more slender profile than the traditional somewhat squat domestic kettle, it became the practice to provide separate steam sensor and heating element overtemperature protection controls which were electrically connected to each other. The steam sensor control was again located adjacent to a steam vent provided in the vessel wall at a high level and the heating element overtemperature control was again located near to the bottom of the vessel. Hollow compartments in the body moulding of the vessel, particularly in or adjacent to a handle part of the body moulding enabled the connecting wires extending between the steam sensor and heating element overtemperature controls to be neatly concealed, though at the expense of the handle part of the body moulding being relatively massive. One such arrangement is disclosed in GB-A-2 212 664 for example.

More recently, the steam pipe invention has been resurrected as disclosed for example in GB-A-2 318 452 where arrangements are described in which the steam sensor control and the heating element overtemperature control are both located in a bottom part of the vessel underneath a planar 4 heating element of the vessel. Whilst this proposal imposes no design constraints on the shape of the vessel, it can give rise to size constraints in that the base compartment of the vessel must be sufficiently large to accommodate the two controls.

The present invention addresses these considerations and provides an aesthetically advantageous way of incorporating steam sensor and heating element overtemperature controls into an electrically heated water boiling vessel.

Summary of the Invention:

According to the present invention, in one of its aspects, an electrically heated water boiling vessel is provided with a steam sensor concealed within a handle of the vessel adjacent to a steam vent high in the vessel wall, and the vessel wall under the handle is recessed with a water level indicator accommodated in the recess, the water level indicator comprising a plurality of chambers one of which communicates with the interior of the vessel at a low level so as to be filled as the vessel is filled and another of which accommodates electrical conductors extending from the steam sensor.

In an embodiment of the present invention which is described in detail hereinafter, the water level indicator comprises a plastics moulding having three chambers, namely a central chamber for indicating the water level in the vessel, a first side channel for accommodating the electrical conductors and a second side channel serving as a drainage channel for condensate.

The present invention is particularly, though not exclusively, well adapted to vessels formed of metal by deep drawing or by rolling from sheet and seam welding. However, the invention could equally well be applied to a moulded plastics bodied vessel.

The above and further features of the present invention are set forth in the appended claims and, together with the advantages thereof, will be made clear in the following description given with reference to the accompanying drawings.

Description of the Drawin%s:

Figure 1 is a perspective view of an exemplary embodiment of the present invention; Figure 2 is an exploded perspective view of the embodiment of Figure 1; Figures 3A and 3B are perspective views showing the juncture of the handle with the vessel body and illustrating how the steam sensor control is accommodated; Figures 4A and 4B are side elevation and sectional views respectively of a water level indicator moulding, the sectional view being taken on the line B... B shown in Figure 4A; 6 Figure 5 is a perspective view of a power base for use with the embodiment of Figure I. and Figure 6 is a part sectional side elevation view of the embodiment.

Detailed Description of the Embodiment:

Referring first to Figure 1 of the accompanying drawings, the embodiment comprises a cordless electrical water heating appliance having a vessel part 1 and a base part 2, the vessel part 1 being shown in exploded view in Figure 2 and the base part 2 being shown in Figure 5. As is well known, such a cordless appliance has complementary electrical connectors in its two parts which, when the vessel part is seated on the base part, enable electricity to be supplied via the base part to the vessel part. In the illustrated embodiment, the complementary electrical connectors are Otter Controls CS4 and CP7 connectors which are substantially as described in GB-A-2 285 716, these connectors enabling the vessel part to be set down upon the base part in any relative rotational orientation of the two parts.

Figure 2 shows the vessel part 1 in exploded view as comprising a vessel body 3 formed of stainless steel for example by deep drawing or by rolling from sheet and seam welding, followed by finishing operations to form a spout 4 and a recess 5 as shown, the recess 5 having near its lower end an aperture 6 providing for communication with the interior of the vessel. A bottom compartment 7 is welded into the bottom of the vessel and serves to 7 accommodate an electric heating element and the respective part of the abovementioned cordless connector set.

The recess 5 is designed to accommodate a plastics moulding 8 formed with a spigot 9 adapted to be sealingly engaged in the aperture 6 that is provided in the vessel wall. The moulding 8 can be made of a rigid plastics material in a shape such as to conform to the profile of the vessel or can alternatively be made of a flexible plastics material, an elastomeric material for example, which is formed straight and can be bent to conform to the vessel profile when it is assembled to the vessel. As will be described more fully hereinafter, the plastics moulding 8 has three internal chambers or passageways 10, 11 and 12. The central passageway 11 communicates with the spigot 9 as shown in Figures 4B and 6, and the flanking passageways 10 and 12 extend through the moulding from one end to the other.

A handle formed as a hollow main plastics material moulding 13 and a is plastics material cover 14 is adapted to be secured to the vessel body 3 by any convenient means, the handle serving to accommodate a steam sensor control which snap fits into the handle moulding 13. The steam sensor control 15 may for example be as described in GB-A-2 315 161 or GB-A-2 299 859 or in our GB Patent Application No. 9725401.5 and comprises a bimetallic or other thermal actuator in a bistable overcentre mechanism which serves to move a trip lever between positions where it either opens or closes a set of switch contacts. To enable the steam sensor control 15 to be reset after it has 8 operated in response to the boiling of water in the vessel, the trip lever has provision for the attachment thereto of a manually operable rocker knob 16 which projects through an aperture in the handle cover moulding 14. A lid 17 is also provided and can be a fixed lid or a hinged lid connected to the vessel body by any convenient means. In the event that the lid 17 is hinged, an interconnect with the steam sensor control 15 may be provided so that the steam sensor control will inevitably be in its OFF condition so long as the lid is open.

Figures 3A and 3B show details of the accommodation of the steam sensor control 15 in the main handle moulding 13. As shown, the moulding 13 is provided with a notched opening 18 in its uppermost front edge and with a pair of integral internal fins 19, one on each side of the opening 18. As can be seen from Figures 3A and 3B and also from Figure 6, the co-operation of the handle cover 14 with the main handle moulding 13 and with the lid 17 causes the opening 18 to define a steam vent 20 for enabling steam generated within the upper part of the vessel to access the steam sensor control 15. Other formations 21 within the main handle part 13 and on the handle cover 14 co-operate with the body of the steam sensor control 15 to confine the steam to a compartment wffich is at least substantially isolated from electrical parts of the control, such compartment having a drainage hole 22 (see Figure 3A) which, when the appliance is assembled, communicates with the upper end of passageway 12 that is provided in the plastics moulding 8 for the purpose of 9 enabling condensate or spillage to drain out of the compartment and run down through the moulding 13 to a dispersal vent (not shown) that is provided in the bottom compartment 7 of the vessel.

Electrical connection to the terminals of the steam sensor control 15 are made by means of electrically insulated conductors 23 (see Figure 6) which extend from the back end of the control, loop under the control and through an aperture 24 provided in the main handle moulding 13 and then extend down through passageway 10 in the moulding 8 and into the base part 7 of the vessel where they are appropriately connected in circuit with the heating element of the vessel, the associated overtemperature control and the appliance inlet connector.

The moulding 8 is advantageously contoured to blend with the contours of the vessel body 3, either in a flush manner or with a degree of projection from the curved surface of the vessel body. A judicious amount of projection will enable the water level indicator on the moulding to be seen from both sides of the vessel. The moulding 8 can be made of a transparent or translucent material to enable the water level in the central passageway 11 to be seen. This would also allow the wires in passageway 10 and condensation in passageway 12 to be seen and this could be avoided, if desired, by overprinting or painting relevant parts of the mouldings and/or texturing the surface of the moulding to make it opaque. Alternatively, the moulding 8 could be a two part construction with a clear window, to enable the water level 1 in passageway 11 to be clearly seen, moulded within an opaque body moulding. A float could be provided within passageway 11 and, as described in our British Patent Application No. 9725139.1 the level indicator could be illuminated.

As previously mentioned herein the moulding 8 could advantageously be formed of a flexible material such as amorphous polypropylene or a polyester elastomer or silicone rubber. By doing this any lack of precision of the fit of the moulding into the recess 5 in the vessel body 3 could be accommodated and the moulding could be secured at its ends by the handle and base mouldings of the appliance. Moulding from elastomeric material also enables any seals that might be required to be formed integrally with the moulding which would enhance the safety of the assembly and also make it less costly than if separate seals had to be provided.

Having thus described the present invention by reference to a specific embodiment, it is to be understood that the embodiment is exemplary only and that modifications and variations thereto are possible without departure from the spirit and scope of the appended claims. For example, whereas the moulding 8 has three closed passageways 10, 11 and 12, only the central, water level indication passageway actually needs to be closed. The other two passageways, or either of them, could alternatively be formed as a recess within the rear surface of the moulding 8 such as to define with the adjacent surface of the vessel body the appropriate channels for accommodating the 11 electrical connections to the steam sensor control and for draining condensation from the steam sensor control. Additionally, whereas the described embodiment comprises a metal vessel body, it could equally well be formed of a moulded plastics material. Furthermore, any kind of electrical heating element could be employed, a planar heating element for example comprising a sheathed resistance heating element clamped or clenched to the underside of a plate or a thick film heating element comprising a substrate having a resistance heating track or layer formed thereon.

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Claims

CLAIMS:

1. An electrically heated water boiling vessel including a steam sensor within a handle of the vessel adjacent to a steam vent provided high in the vessel wall and wherein the vessel wall is recessed under the handle and a water level indicator comprising a plurality of chambers one of which communicates with the interior of the vessel at a low level so as to be filled as the vessel is filled and another of which accommodates electrical conductors extending from the steam sensor.

2. An electrically heated water boiling vessel as claimed in claim 1 wherein the water level indicator has three chambers, one communicating with the vessel interior, another accommodating said electrical conductors and a third providing for drainage of condensation from the location of the steam sensor.

3. An electrically heated water boiling vessel as claimed in claim 1 or claim 2 wherein all of the chambers are bounded by fully enclosing walls of the water level indicator.

4. An electrically heated water boiling vessel as claimed in any preceding claim wherein a float is provided within the chamber of the water level indicator that communicates with the vessel interior.

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5. An electrically heated water boiling vessel as claimed in any preceding claim wherein means are provided for illuminating the water level indicator.

6. An electrically heated water boiling vessel as claimed in any preceding claim wherein the water level indicator comprises a moulded plastics body within which said chambers are formed, a low level spigot adjacent one end of the moulding sealingly engaging an aperture in the vessel wall and providing communication with the vessel interior and said one chamber, and the chambers being open-ended at the other, upper end of the moulded plastics body.

7. An electrically heated water boiling vessel as claimed in claim 6 wherein said moulded plastics body is formed of a rigid plastics material and is shaped to fit the profile of the vessel and of the recess in which it is accommodated.

8. An electrically heated water boiling vessel as claimed in claim 6 wherein said moulded plastics body is formed of a flexible plastics material and is bent during assembly to the vessel so as to conform to the profile of the vessel.

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9. An electrically heated water boiling vessel as claimed in claim 8 wherein said flexible plastics material is an elastomeric material.

10. An electrically heated water boiling vessel as claimed in any preceding claim wherein the steam sensor is housed within the handle of the vessel in such a manner that a steam compartment is provided which is substantially isolated from electrical switch and terminal parts of the steam sensor.

An electrically heated water boiling vessel as claimed in any preceding claim wherein said steam sensor comprises a bimetallic actuator.

12. An electrically heated water boiling vessel as claimed in claim 11 wherein said bimetallic actuator is in a bistable overcentre arrangement.

13. An electrically heated water boiling vessel as claimed in claim 12 wherein said overcentre arrangement includes a contact-operating trip lever, and the vessel includes a manual control enabling said trip lever to be operated.

14. An electricafly heated water boiling vessel as claimed in any preceding claim wherein the vessel is the vessel part of a cordless electrical water boiling appliance comprising a vessel part and a base part, the vessel part and base 0 part having co-operating electrical connectors enabling the vessel part to be (5 powered via the base part when it is operatively located with respect to the base part.

15. An electrically heated water boiling vessel as claimed in claim 14 wherein said co-operating electrical connectors are such as to enable the vessel part to be operatively located with respect to the base part in any relative rotational orientation of the two parts.

16. An electrically heated water boiling vessel as claimed in any preceding claim wherein the heating element of the vessel comprises an underfloor heating element in the form of a plate having a sheathed resistance heating element clamped or clenched to the undersurface thereof

17. An electrically heated water boiling vessel as claimed in any of claims 1 to 15 wherein the heating element of the vessel comprises a thick film heating element.

18. An electrically heated water boiling vessel as claimed in any of the preceding claims including a heating element overtemperature: control operatively associated with the heating element.

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19. An electrically heated water boiling vessel as claimed in any of the preceding claims wherein the vessel is formed of metal.

20. An electrically heated water boiling vessel as claimed in any of claims 1 to 18 wherein the vessel is formed of moulded plastics material.

21. An electrically heated water boiling vessel substantially as herein described with reference to the accompanying drawings.