WO2002011590A1

WO2002011590A1 - Steam sensor arrangement in a liquid heating vessel

Info

Publication number: WO2002011590A1
Application number: PCT/GB2001/003537
Authority: WO
Inventors: Peter Hallam Wright; Antonio Martin Gaeta
Original assignee: Otter Controls Ltd
Current assignee: Otter Controls Ltd
Priority date: 2000-08-07
Filing date: 2001-08-07
Publication date: 2002-02-14
Anticipated expiration: 2003-02-07
Also published as: GB2365319A; AU2001276524A1; GB2365319B; GB0019402D0

Abstract

Cordless electric kettles and hot water jugs fitted with planar heating elements (3) and with a steam sensor (5) and one or more element overtemperature protector controls (4) housed in a compartment (2) beneath the heating element can suffer from the problem that exhaust steam from the steam sensor condenses on the surface of the base unit of the appliance, forming a pool or puddle and leading a user of the appliance to the conclusion that the vessel is leaking. To avoid this, the invention proposes to vent exhaust steam sideways from the bottom of the kettle/jug rather than downwardly as has been conventional.

Description

STEAM SENSOR ARRANGEMENT IN A LIQUID HEATING VESSEL

Field of the Invention:

This invention concerns improvements relating to liquid heating vessels and more particularly concerns water boiling vessels, such as kettles

and jugs for example, which incorporate a steam or boil control arranged to be responsive to the generation of steam when water boils in the vessel to switch

off or reduce the power supplied to an electric heating element of the vessel.

Background of the Invention:

The provision of steam controls in electric kettles and hot water jugs is

well known. Fairly recently, however, the use of planar heating elements in such appliances has become commonplace, with the planar heating element

being either of the underfloor type comprising a metal plate having a sheathed

heating element affixed to the underside thereof or of the thick film type

comprising a metal substrate having a thick film heater track on the underside

thereof. Additionally, cordless appliances, comprising a vessel proper and a

base upon which the vessel has to be seated in order for power to be supplied

through the base to the vessel heating element, have become popular. Cordless water heating appliances provided with planar heating elements and with steam controls have developed such that the preferred construction has

the steam control located in a compartment of the vessel proper underneath

the planar heating element, such compartment also serving to accommodate

an element protector control designed to switch off the power supply to the

vessel heating element in the event of the heating element temperature rising

above a predetermined safe level.

Disclosed in GB-A-2 339 088 is an element protector control which

we manufacture and sell as our X4 series control, and disclosed in GB-A-2 331 848 is a steam control which we manufacture and sell as our Z5 steam control. The X4 element protector control is designed to be usable with the Z5 steam control which simply connects onto terminals provided on the side of the X4 control. The X4/Z5 combination is designed for use with cordless kettles and hot water jugs and the X4 has integrated into its

construction a 360° inlet connector which, as is nowadays well known, enables the vessel proper to be set down onto its base in any rotational

orientation with respect to the base. A similar control is available from Strix Ltd. and is substantially as described in GB-A-2 339 496.

In use of our X4/Z5 controls combination and of the similar Strix

control it is usual to provide a steam tube to duct steam from inside the vessel

proper down to the steam control in the compartment beneath the heating

element, the steam tube being formed in the body of the vessel proper or

alternatively being formed as a separate tube passing through the heating

element. It is furthermore usual to vent the steam through the bottom of the vessel proper after it has caused the steam control to operate. We have

identified a problem with this constructional arrangement, particularly if the

Strix control is used, in that, as the steam leaves the vessel bottom, it impinges

upon the upper surface of the base part of the cordless appliance which is

relatively cold so that the steam condenses and forms a puddle on the surface

of the base. This puddle is clearly visible when the vessel is lifted from its

base and may cause the user to think that the vessel is leaking.

Objects and Summary of the Invention;

It is the object of the present invention to overcome or at least substantially reduce the abovementioned problem and thereby prevent a user

from concluding that his appliance is leaking and returning it to whence it was purchased. According to the present invention the abovementioned object can be

achieved by arranging for venting of exhausted steam laterally from the lower periphery of the body of the vessel proper, rather than downwardly, so that it

does not impinge on the cold surface of the appliance base part and does not

condense there.

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

appended claims and will be well understood from consideration of the

following description of an exemplary embodiment which is illustrated in the

accompanying drawings. Description of the Drawings

Figure 1 is a cross-sectional side-elevation view of a cordless hot

water jug embodying the present invention;

Figure 2 is a cross-sectional side-elevation view of the hot water jug of

Figure 1 taken on an axis 90° rotated from that on which Figure 1 is taken;

Figure 3 is a perspective view of a vessel body moulding comprising

part of the hot water jug of Figures 1 and 2; Figure 4 is an enlarged cross-sectional view of a bottom part of the vessel body moulding shown in Figure 3; and

Figures 5A to 5F show various views of a bottom moulding to be affixed to the bottom of the vessel body moulding shown in Figures 3 and 4,

Figure 5A being a top plan view, Figures 5B and 5C being cross-sectional side-elevation views on the lines G...G and H...H of Figure 5A, Figure 5D

being a perspective view of the bottom moulding from the side thereof which is outermost when the bottom moulding is assembled with the vessel body

moulding, and Figures 5E and 5F being perspective views from different

viewpoints of the other side of the bottom moulding.

Detailed Description of the Embodiment: Referring first to Figures 1 and 2, the illustrated appliance is a cordless

hot water jug comprising a vessel proper 1 and a base 2 upon which the vessel

proper has to be seated in order that power can be supplied through the base to

a planar heating element that is provided in the vessel proper. In the

illustrated embodiment, the heating element is designated 3 and is of the

aforementioned thick film type. Associated with the heating element 3 is an

X4 element overtemperature protection control 4 and a Z5 steam sensor 5 as

aforementioned. The X4 control incorporates a 360° inlet connector which, when the vessel proper 1 is seated on its base 2, mates with a 360° outlet connector (our CS4 product, for example, which is substantially as described in GB-C-2 285 716) to enable power supplied to the base to be connected through to the vessel proper.

h operation of the appliance abovedescribed, when water is heated to boiling in the vessel proper, steam is generated and accesses the Z5 steam sensor by way of a duct 6 which is moulded into the plastics material body of

the vessel proper 1. The steam impinges upon the bimetallic actuator of the

Z5 steam sensor and causes the sensor to operate, thereby switching off the

power supply to the vessel heating element 3. An on/off lever 7 is pivotally

mounted in the vessel proper 1 and engages with the trip lever of the Z5 steam

sensor to enable the steam sensor switch to be operated manually, especially for resetting the switch after it has operated.

Figure 3 shows a moulded plastics body part 8 of the vessel proper 1 in perspective view and from underneath. A seating 9 for the thick film heating element 3, which is not shown in Figure 3, is provided, together with

attachment points 10 enabling the heating element to be secured in place. The

bottom end 11 of the steam duct 6 is shown and its inward face 12 is shaped

to fit closely to the external profile of the respective part of the steam sensor 5,

formations (not shown) being provided on the steam sensor for making

substantially sealing engagement with the steam duct. As will be described

hereinafter, the bottom moulding illustrated in Figures 5A to 5F engages substantially sealingly with the steam sensor in similar fashion so that the steam sensor is substantially sealingly enclosed in an enclosure defined at the bottom end of the steam duct. Vents 13 are provided in the bottom edge of

the plastics body part 8 for enabling steam to exit laterally (with respect to the normal vertical orientation of the appliance) from this enclosure.

Figure 4 is an enlarged cross-sectional showing of a bottom part of the vessel body moulding 8. The thick film heating element 3 is shown seated in

the seating 9 with a seal 14 around the element periphery and a clamping ring

15 holding the element in place. The steam duct 6 is shown terminating in its

bottom wall 12 and one of the vents 13 is shown.

Figures 5 A to 5F show a moulded plastics bottom closure 16 for the

body moulding 8 of the vessel proper. As shown, the bottom closure 16 is

concavely dished complementarily to the convex upper surface of the base

part 2 of the appliance and has a central opening through which the outlet

connector of the base part can access the inlet connector of the appliance

proper. Of particular relevance to the present invention are the formations generally referenced 17 which interface with the steam sensor 5 when the

bottom closure 16 is affixed to the body moulding 8 to complete the assembly

of the vessel proper 1. As mentioned hereinbefore, these formations 17

co-operate with the shaped bottom end of the steam duct 6 to enclose the

steam sensor 5 substantially sealingly so that the only exit available for

exhausted steam is provided by the vents 13 which direct the steam laterally outwards away from the X4 element protector control 4 and away from the

underlying upper surface of the base part 2 of the appliance. The bottom closure 16 may be affixed by means of screw-threaded fastenings to the X4 control and/or may be arranged to snap fit into the bottom of the vessel body

moulding 8.

It will be appreciated that the arrangement described avoids the problem of condensate forming on the surface of the base 2 of the appliance by directing exhaust steam outwards away from the base. The concave shape of the bottom closure 16 will also assist draining in the event that slight

condensation might occur in the stem sensor enclosure, but this is not an essential feature of the invention.

Having thus described the invention by reference to a specific

embodiment, it is to be well appreciated that the described embodiment is

exemplary only and that modifications and variations thereto are possible

without departure from the spirit and scope of the invention. For example,

while the invention has been described in the foregoing by reference to cordless appliances, the teachings of the invention are nonetheless applicable

to corded appliances.

Claims

Claims:

1. An electrically heated water boiling vessel having a steam sensor

mounted in a bottom compartment of the vessel with a steam duct conveying

steam generated in operation of the vessel to the steam sensor, and wherein

means are provided for venting exhaust steam laterally outwardly of the

vessel.

2. A vessel as claimed in claim 1 having a planar heating element and

wherein said compartment is below the heating element.

3. A vessel as claimed in claim 1 or 2 wherein the steam duct terminates

in an enclosure sealingly embracing part at least of said steam sensor, said

enclosure having one or more apertures arranged to vent steam laterally.

4. A vessel as claimed in any of the preceding claims comprising a

cordless vessel proper and a base, the arrangement being such that power can

be conducted from the base to the vessel proper when the vessel proper is

seated on the base.

5. A vessel as claimed in claim 4 wherein the vessel proper and the base

are provided with respective parts of an electrical connector set which enables

the vessel part to be operatively coupled to the base throughout 360° of

relative rotational orientation.

6. An electrically heated water boiling vessel substantially as herein

described with reference to the accompanying drawings.