WO2001084992A1

WO2001084992A1 - Electric kettle

Info

Publication number: WO2001084992A1
Application number: PCT/AU2001/000507
Authority: WO
Inventors: Donald Charles Wride
Original assignee: Donald Charles Wride
Priority date: 2000-05-05
Filing date: 2001-05-03
Publication date: 2001-11-15
Also published as: AUPQ730800A0

Abstract

An electric kettle (10) including: an inner shell (11) defining a water storage chamber having an upwardly directed opening (14); an outer shell (16) spaced from and substantially surronding said inner shell (11); an insulating chamber (19) between said inner shell (11) an said outer shell (16), said insulating chamber containing insulating material (41) or being an adiabatic vacuum chamber (119) to thermally insulate said inner shell (11); a lid (15) connected to one or both of said inner and outer shell (11, 16) and adapted to close said upwardly directed opening (14), said lid (15) having a flow passage (29) therein for filling and/or emptying said water storage chamber; an electric heating element (31) in said water storage chamber for heating water contained therein, and externally accessible power supply means (34) electrically connected to said electric heating element (31).

Description

ELECTRIC KETTLE

TECHNICAL FIELD OF THE INVENTION

This invention relates to electric kettles, or jugs as they are sometimes called, of the type normally used in domestic situations . BACKGROUND ART

Modern electric kettles typically have a water storage container with an upwardly directed opening and an electric heating element positioned in the compartment for immersion in water contained therein. Historically, the water storage containers have been constructed of ceramic or metal materials but they are now generally made of plastics materials. While those made of plastics materials have many desirable properties, for example, they are less breakable than ceramic kettles and are thermally better insulated and are perceived to be electrically safer than metal kettles, they still do not keep the water as hot as desired for as long as some persons would like. In some instances, a person may desire a second cup of tea a few minutes after boiling the kettle and because the kettle does not keep the water hot enough, it is necessary to re-boil the kettle. Thus, the kettle can not be taken from the kitchen to the dining table and used simply to refill the cup. In other instances, one person may boil the kettle and make a cup of tea and then a few minutes later another person has to re-boil the kettle to also make a cup of tea, as can be appreciated in family situations. DISCLOSURE OF THE INVENTION

With the foregoing in view the present invention resides broadly in an electric kettle including: an inner shell defining a water storage chamber having an upwardly directed opening; an outer shell spaced from and substantially surrounding said inner shell; an adiabatic vacuum chamber between said inner shell and said outer shell and substantially surrounding said inner shell, said adiabatic vacuum chamber being adapted to thermally insulate said inner shell; a lid connected to one or both of said inner and outer shells and adapted to close said upwardly directed opening, said lid having a flow passage therein for filling and/or emptying said water storage chamber; and an electric heating element in said water storage chamber for heating water contained therein, and externally accessible electric power supply means electrically connected to said electric heating element.

Preferably, said adiabatic vacuum chamber is formed in a separate unit comprising spaced apart walls defining an evacuated chamber, and then fitted in the space between the inner and outer shells . This is particularly advantageous where the inner and outer shells are separate components. However, where the inner and outer shells form an integral unit and the space therebetween can be effectively evacuated then such space may form the adiabatic vacuum chamber, for example where the inner and outer shells are formed of stainless steel.

In another aspect the invention resides broadly in an electric kettle including: an inner shell having an inner side wall and an inner base wall defining a water storage chamber having an upwardly directed opening; an outer shell having an outer side wall spaced from said inner side wall and an outer base wall spaced from said inner base wall; insulating means between said inner side wall and said outer side wall and between said inner base wall and said outer base wall, said insulating means comprising spaced apart walls defining an evacuated chamber; a lid connected to one or both of said inner and outer shells and adapted to close said opening, said lid having a flow passage therein for filling and/or emptying said water storage chamber; an electric heating element in said water storage chamber for heating water contained therein; externally accessible electric power supply means electrically connected to said electric heating element.

Preferably, said electric heating element is suspended from said lid and is connected to said externally accessible electric power supply means via said lid. Advantageously, such arrangement avoids any penetrations through the inner and outer shells and the insulating means thus decreasing the possibility of damage to the vacuum chamber during manufacture . BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more clearly understood and put into practical effect, the invention will now be described with reference to the accompanying drawings wherein:

Fig. 1 is a cross sectional elevation of an electric kettle according to the invention along a vertical diametral plane, and

Fig. 2 is a cross sectional elevation of another electric kettle according to the invention along a vertical diametral plane. DETAILED DESCRIPTION OF THE DRAWINGS

The electric kettle 10 illustrated in Fig. 1 includes an inner shell 11 which is substantially cylindrical in shape and forming a water storage chamber having a side wall 12, a base wall 13 and an upwardly directed opening 14. A lid 15 is fitted to the opening as will be described later. The inner shell is surrounded by an outer shell 16 also of substantially cylindrical shape having a side wall 17 and a base wall 18 and which together with the inner shell defines an annular space between the respective side walls and a cylindrical space between the respective base walls which together form an insulating chamber 19. In this embodiment, the inner shell has an outwardly extending flange 20 at its upper end which forms a closure for the chamber 19 and a lip 22 extends upwardly from the flange having an internal thread 23 and an external thread 24 for a purpose which will be described later. A complementary thread 25 is provided on the inner face of the outer shell at its upper end so that the inner shell and the outer shell can be screwed together to close the chamber 19.

The lid 15 has a downwardly depending cylindrical skirt portion 26 which has an external thread 27 corresponding to the internal thread on lip 22 for securing the lid to the inner shell. In order to prevent leakage, an O-ring 28 is seated between the skirt portion 26 and the flange portion 21 of the inner shell. Suitably a spout 29 is provided in the lid for filling the inner shell with water and also for emptying water from the inner shell. An electric heating element 31 is suspended in the inner shell near its lower end by two relatively stiff conductor wires 32 which terminate in a junction box 33 of known type. The conductors are connectors in the junction box to an electrical power supply cable 34 which is housed in the handle 36 which is secured to the lid 15.

An insulator 41, shown diagrammatically in cross hatching, of generally cylindrical shape is fitted in the chamber 19 and rests at its lower end on a foam rubber cushion 42 and is supported against movement at its upper end by a foam rubber ring 43 which rests against the lower face of flange portion 20. Suitably, the insulator surrounds the side wall 12 and the base wall 13 of the inner shell. The insulator, comprises spaced apart inner and outer walls which are joined at their upper ends to form an adiabatic vacuum chamber therebetween. The walls may be formed of metal, preferably stainless steel, or alternatively of glass, or any other suitable material.

The electric kettle 110 shown in Fig. 2 is very similar to that of Fig. 1 and corresponding numbers are used to reference corresponding items , but prefaced by a "1". The main difference is that the inner and outer shells 111 and 116 are formed of stainless steel and are welded together at their upper ends at 124 instead of being screwed together by threads 24 and 25 as in Fig. 1. Moreover, the chamber 119 is evacuated to form an adiabatic vacuum chamber, thus obviating the need for the separate insulator 41. Other suitable materials which allow the chamber to maintain a vacuum could be used instead of stainless steel.

In another embodiment, the inner and outer shells are formed in one piece, with the outer shell being open at its lower end to allow the insulator 41 to be fitted as shown in Fig. 1. In such embodiment, the outer shell is longer than shown in Fig. 1 and has an internal thread at its lower end adapted to receive therein a retainer plug adapted to bear against the cushion 42 and to retain the insulator in the desired position.

The foregoing description has been given by way of illustrative example of the invention, and many modifications and variations which will be apparent to persons skilled in the art may be made without departing from the spirit and scope of the invention as defined in the appended claims .

It will be appreciated that the present invention that the present invention provides an electric kettle which is fast to boiling and more energy efficient than the presently available electric kettle and that also maintains the temperature of the water in the kettle close to boiling point for some time after the kettle has been switched off, thus providing for later cups of tea or the like without re-boiling.

Claims

1. An electric kettle including: an inner shell defining a water storage chamber having an upwardly directed opening; an outer shell spaced from and substantially surrounding said inner shell; an adiabatic vacuum chamber between said inner shell and said outer shell and substantially surrounding said inner shell, said adiabatic vacuum chamber being adapted to thermally insulate said inner shell; a lid connected to one or both of said inner and outer shells and adapted to close said upwardly directed opening, said lid having a flow passage therein for filling and/or emptying said water storage chamber; and an electric heating element in said water storage chamber for heating water contained therein, and externally accessible electric power supply means electrically connected to said electric heating element .

2. An electric kettle including: an inner shell having an inner side wall and an inner base wall defining a water storage chamber having an upwardly directed opening; an outer shell having an outer side wall spaced from said inner side wall and an outer base wall spaced from said inner base wall; insulating means between said inner side wall and said outer side wall and between said inner base wall and said outer base wall, said insulating means comprising spaced apart walls defining an evacuated chamber; a lid connected to one or both of said inner and outer shells and adapted to close said opening, said lid having a flow passage therein for filling and/or emptying said water storage chamber; an electric heating element in said water storage chamber for heating water contained therein; externally accessible electric power supply means electrically connected to said electric heating element.

3. An electric kettle according to Claim 1 or Claim 2, wherein, said adiabatic vacuum chamber is formed in a separate unit comprising spaced apart walls defining an evacuated chamber.

4. An electric kettle according to Claim 3, wherein said separate unit is fitted between said inner and outer shells.

5. An electric kettle according to Claim 3, wherein the space between said inner and outer shells is evacuated to form said adiabatic vacuum chamber.

6. An electric kettle according to Claim 1 or Claim 2, wherein said electric heating element is suspended from said lid and is connected to said externally accessible electric power supply means via said lid.