GB2152802A

GB2152802A - Automatic water heater

Info

Publication number: GB2152802A
Application number: GB08401436A
Authority: GB
Inventors: Peter William Warren; John William Smith
Original assignee: SWAN HOUSEWARES Ltd
Current assignee: SWAN HOUSEWARES Ltd
Priority date: 1984-01-19
Filing date: 1984-01-19
Publication date: 1985-08-14
Also published as: GB8401436D0; FR2558575B3; FR2558575A3; DE8501451U1

Abstract

In an automatic water heater, for instance, a jug kettle, the electricity supply to the element (3) is controlled by a switch unit (4) which incorporates a heat-sensitive switch (9, 10) responsive to the temperature of steam conveyed from the inside of the container (1). The steam is conveyed to the switch unit (4) by a steam passage defined by a recess (21) in the handle (5) and the adjacent exterior surface of the container wall (6). This simple arrangement facilitates cleaning of the inside of the kettle. In an alternative embodiment (not shown) the steam passage may be contained wholly within the handle. <IMAGE>

Description

SPECIFICATION Automatic water heaters This invention relates to automatic water heaters, such as automatic kettles and jug-kettles, of the kind in which in use water in a container is heated by an electric element immersed in the water, the electricity supply to the element being controlled by a heat sensitive switch disposed externally of the container and below the water level and which is responsive to the temperature of steam conveyed by a duct from the space in the container above the water level to the switch. Such water heaters will hereinafter be referred to as being of the kind described.

In water heaters of the kind described, the heat sensitive switch is often incorporated within a unit which is secured to the wall of the container adjacent to the mounting for the electric element, and the unit also incorporates the terminals for the electric element. In one known water heater of this type the duct is in the form of a pipe which has an opening above the water level and which extends downwardly within the container to the mounting for the electric element where it passes through the container wall so as to direct steam onto the heat sensitive switch. This arrangement is quite complicated and the pipe within the container of the water heater is a hindrance to effective cleaning of the container.

According to the present invention there is provided an automatic water heater of the kind described wherein the duct is in the form of a downwardly extending passage within or at least partially defined by a handle of the heater.

The passage may be contained wholly within the handle. Alternatively, the passage may be defined by a recess provided in the handle and an adjacent external surface of a wall of the container.

The invention is particularly applicable to automatic water heaters, for instance automatic kettles of the type known as jug-kettles, which have a handle secured to a substantially vertical side wall of the container above a heat sensitive switch unit.

The invention may also be applied to water heaters of the type which have a handle extending over the top of the container and down the side of the container to a switch unit.

Preferably the unit which incorporates the heat sensitive switch also incorporates the terminals for the electric element.

Conveniently, the passage for steam within or defined by the handle has an inlet for steam from the inside of the container and an outlet to the unit which incorporates the heat sensitive switch.

The inlet is preferably adjacent to an opening provided in the side wall of the container which allows steam to pass from the inside of the container into the passage for steam. Alternatively, this opening may be provided in a top surface of, or a lid for, the container.

The outlet is conveniently constructed and arranged in such a manner as to direct steam onto a steam-actuated element of the heat sensitive switch Preferably, at least one longitudinal rib may be provided in the steam passage to divide the flow of steam in the passage into more than one flow path.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure lisa sectionai view of a kettle in accordance with the present invention; Figure 2 is a sectional view of the handle ofthe kettle shown in figure 1; Figure 3 is a view in the direction A shown in figure 2; Figure 4 is a section on the line lV-IV of figure 2; and Figure 5 is a section on the line V-V of Figure 2.

The kettle illustrated in figure 1 is of the type often referred to as a jug-kettle and comprises a substantially cylindrical container 1, a lid 2, an electric element 3 within the container 1, a switch unit 4, and a handle 5.

As shown in figure 1, the electric element 3 is secured to the substantially cylindrical wall 6 of the container 1 by a mounting plate 7 and the switch unit 4 is secured to the outer surface of the wa 11 6 adjacent to the mounting plate 7.

The switch unit 4 has a casing 8 which includes the terminals for the electric element 3, and a heat sensitive switch which is of the usual type having a steam-actuated element 9, for example a bimetallic strip, a movable operating member 10 biassed by an overcentre spring arrangement (not shown), and a manually engageable member 11 attached to the operating member 10. The operating member 10 is movable between an "on" position and an "off" position by manual operation of the manually engageable member 11 and it is arranged to be moved into its "off" position when steam directed onto the steam-actuated element 9 heats the element 9 sufficiently to actuate it.Additionally, the operating member 10 may be moved into its "off" position when the heating element is energised and is not covered by water in the kettle, for example by a push rod engageable with a thermally expandable member in contact with a part of the mounting plate adjacent to the heating element.

The switch unit need not be described in any further detail apart from that an aperture 12 is provided in the upper portion 13 of the casing 8 directly above the steam-actuated element 9.

The handle 5 of the kettle is secured to the outer surface of the container wall 6 above the switch unit 4 by upper and lower screws 14 and 15 respectively.

Each screw 14, 15 extends through a respective aperture in the wall 6 and is received by a threaded hole 16, 17 respectively, provided in the surface 20 of the handle 5 which faces the wall 6 of the container 1.

In the surface 20 of the handle 5 there is provided an oblong recess 21 which extends downwards from just below the hole 16 for the uDper screw 14 to just above the hole 17 for the lower screw 15. The oblong recess 21 has two vertical sides 22 and an inner surface 23 which, together with the adjacent outer surface of the wall 6 of the container 1, define a downwardly extending steam passage when the handle 5 is secured to the container 1.

The upper part of the steam passage is adjacent to an opening 24 which is provided in the wall 6 of the container 1 below the aperture 16 for the upper screw 14 and serves as an inlet for steam from the inside of the container 1. A portion 25 of the wall 6 above the opening 24 is bent inwardly so as to direct steam out through the opening 24.

As shown in Figures 3 and 5, on each side of the hole 17 for the lower screw 15 there is a rearwardly inclined outlet channel 26 leading from the bottom of the steam passage to a central outlet aperture 27 in the underside 28 of the handle 5. When the handle 5 is secured to the container 1, the outlet aperture 27 is disposed directly above the aperture 12 in the upper portion 13 of the switch casing 8. To the rear of the outlet aperture 27 at the underside 28 of the handle a projection 29 is provided to direct steam from the outlet channels 26 through the aperture 12 in the switch casing 8 and onto the steam-actuated elememt 9 of the heat sensitive switch.

As shown in figures 2,3 and 4 there are two longitudinally extending ribs 30 provided on the inner surface 23 of the recess 21 which split up the downward flow of the steam in the passage into three paths.

In use the container 1 of the kettle shown in figure 1 is filled with a quantity of water at least sufficient to cover the electric element 3. The element 3 is switched on by depression of the manually engageable member 11 which causes the operating member 10 to move into its "on" position. The water in the container 1 is heated by the element 3 and when the water starts to boil steam is produced in the space above the water level in the container 1.

Some of the steam produced is directed by the bent portion 25 of the container wall 6 out through the opening 24 and into the steam passage defined by the recess 21 in the handle 5 and the adjacent outer surface of the wall 6. The steam flows downwardly in the passage in three flow paths defined by the ribs 30 and the sides 22 of the recess 21. From the bottom of the steam passage, the steam flows through the outlet channels 26 and the outlet aperture 27 in the handle and the aperture 12 in the switch casing 8 and onto the steam-actuated element 9 of the heat sensitive switch. The element 9 is actuated by the temperature of the steam and moves the operating member 10 into its "off" position automatically switching off the supply to the electric element 3.

The operating member 10 may thereafter be reset into its "on" position by depression of the manually engageable member 11.

The unit of the heat sensitive switch is preferably so constructed and arranged as to enable water to escape from the unit when the steam condenses.

The ribs 30 in the recess 21 provide an obstruction to the downward flow of steam which causes a build up of pressure within the steam passage and this helps to ensure that a substantial body of steam is directed onto the steam-actuated element 9. This helps to prevent premature actuation of the element 9 which may otherwise be caused by water vapour entering the steam passage and flowing straight down the passage to the heat sensitive switch before the water in the container 1 boils.

In the embodiment shown in the drawings there is no sealing means provided between the surface 20 of the handle 5 surrounding the recess 21 and the outer surface of the container wall 6. Such sealing means may be provided, but the provision of sealing means is not considered to be essential because the construction and arrangement of the two ribs 30 is such as to ensure that a sufficient amount of steam flows down the centre flow path between the ribs 30 into the heat sensitive switch to actuate the steam-actuated element.

It will be appreciated that many modifications may be made to the embodiment of the invention shown in the drawings. For example, the arrangement of the inlet to and of the outlet from the steam passage may be substantially modified, and the number and shape of the ribs 30 in the steam passage may be varied to produce a different steam flow in the passage.

In an alternative embodiment (not shown) the steam passage may be wholly contained within the handle instead of being defined by a recess in the handle and the wall of the container.

Claims

1. An automatic water heater of the kind described wherein the duct is in the form of a downwardly extending passage within or at least partially defined by a handle of the heater.

2. An automatic water heater according to claim 1 wherein the passage is contained whoily within the handle.

3. An automatic water heater according to claim 1 wherein the passage is defined by a recess provided in the handle and an adjacent external surface of a wall of the container.

4. An automatic water heater according to any of the preceding claims wherein the handle is secured to a substantially vertical side wall of the container above a heat sensitive switch unit.

5. An automatic water heater according to any of claims 1 to 3 wherein the handle extends overthe top of the container and down the side of the container to a heat sensitive switch unit.

6. An automatic water heater according to claim 4 to claim 5 wherein the heat sensitive switch unit also incorporates terminals for the electric element.

7. An automatic electric jug kettle substantially as described herein with reference to and as illustrated by the accompanying drawings.

7. An automatic water heater according to any one of claims 4 to 6 wherein the passage has an outlet to the heat sensitive switch unit which is constructed and arranged in such a manner as to direct steam onto a steam-actuated element of the heat sensitive switch.

8. An automatic water heater according to any of the preceding claims wherein the passage has an inlet for steam from the inside of the container which is adjacent to an opening provided in a side wall of the container.

9. An automatic water heater according to claim 8 wherein a portion of the side wall of the container above the opening is bent inwardly so as to direct steam from inside the container out through the opening.

10. An automatic water heater according to any of claims 1 to 7 wherein the passage has an inlet for steam from the inside of the container which is adjacent to an opening provided in a top surface of, or a lid for, the container.

11. An automatic water heater according to any of the preceding claims wherein at least one longitudinal rib is provided in the passange to divide the flow of steam in the passage into more than one flow path.

12. An automatic water heater substantially as described herein with reference to and as illustrated by the accompanying drawings.

Amendments to the claims have been filed, and have the following effect: *(a) Claims 1 to 12 above have been deleted or textually amended.

*(b) New or textually amended claims have been filed as follows:

1. An automatic electric jug kettle of the kind in which in use water in an upright container is heated by an electric element immersed in the water, the electricity supply to the element being controlled by a heat sensitive switch disposed externally of the container and below the water level and which is responsive to the temperature of steam conveyed by a duct from a steam space in the container above the water level to the switch, wherein the jug kettle has a handle having a portion in contact with the upright wall of the container, the portion being formed with a recess which, together with the wall of the container, defines a downwardly directed passage from an opening through the wall of the container from the steam space into the passage and forming at least a part of the duct.

2. An automatic electric jug kettle according to claim 1 wherein at least one longitudinal rib is provided in the passage to divide the flow of steam in the passage into more than one flow path.

3. An automatic electric jug kettle according to claim 1 or claim 2 wherein a portion of the side wall of the container above the opening is bent inwardly so as to direct steam from inside the container out through the opening.

4. An automatic electric jug kettle according to any of the preceding claims wherein the handle is secured to the upright wall of the container above a heat sensitive switch unit.

5. An automatic electric jug kettle according to claim 4 wherein the heat sensitive switch unit also incorporates terminals for the electric element.

6. An automatic electric jug kettle according to claim 4 or claim 5 wherein the passage has an outlet to the heat sensitive switch unit which is constructed and arranged in such a manner as to direct steam onto a steam-actuated element of the heat sensitive switch.