GB2090064A - Electric kettles - Google Patents

Abstract

An electric kettle comprises an immersion heater 12; a switch assembly secured to the head 22 of the heater 12; and incorporating a dry overload actuator 41, 43 for opening switch contacts 16 upon overheating of the head 22 and a steam responsive assembly incorporating a steam responsive actuator 82 mounted on a body 80 which is adjustably clamped to the head 22 independently of the switch assembly by clamping means 31, 35, 36 to allow the steam responsive assembly to be aligned with a steam vent 33 irrespective of the accuracy of the positioning of the heater element 12 and steam vent 33. <IMAGE>

Description

SPECIFICATION Improvements relating to vessels for heating liquids This invention concerns improvements relating to vessels for heating liquids, which vessels are provided with an electrical immersion heater assembly and a switch assembly responsive to overheating of the electrical immersion heater assembly and to boiling of liquid in the vessel to switch off the electrical supply to the immersion heater assembly and to boiling of liquid in the vessel to switch off the electrical supply to the immersion heater assembly.

It is known, for example, from the published Specification of British Patent Application No.

7928416 (G.B. 2036541A) to provide a hole or vent in an upper part of the wall of the vessel and to provide the switch assembly with a steam responsive actuating mechanism which is actuable by a bimetal device disposed adjacent to the hole or vent so as to be subjected to steam issuing from the vessel via the hole or vent. In this switch assembly, the electrical components, such as the switch contacts and the conductors connecting the switch contacts to the immersion heater device and to electrical input terminal pins, are located in a chamber adjacent to a head of the immersion heater device, which head extends through a lower aperture in the wall of the vessel, some distance below the hole or vent. The electrical components are thus protected from exposure to dirt and water.

The steam responsive actuating mechanism extends a considerable vertical distance from adjacent to the hole or vent to the head, and is carried on a body of the switch assembly, which body also carries the electrical components and is mounted on the head so as to clamp a dry overload actuating mechanism to the head, so that the dry overload actuating mechanism is responsive to overheating of the immersion heater device to actuate the switch contacts.The body is an assembly comprising a vertically elongate main moulding, on which the steam responsive actuating mechanism is mounted, and a carrier moulding on which the electrical components are mounted, which carrier moulding can be fitted to the head to enable the immersion heater, dry overload responsive actuating mechanism and electrical components to be tested (prior to being fitted to the vessel and prior to the main moulding being connected to the carrier moulding).

However, some considerable skill is needed to assemble the vessel so as to ensure that the head is secured to the vessel in a predetermined position so as to locate the bimetal device in position adjacent the vent or hole and to locate the main moulding in a position to receive an outer cover.

The skill required to assemble the vessel can be reduced by utilising jigs to pre-align the vessel and immersion heater assembly, or by providing cooperating means on the head and vessel wall to ensure that the head is located properly prior to being secured in position, but such expedients are costly.

An object of the invention is to facilitate assembly of a vessel which can be constructed so as to afford the advantages of reliability, ease of manufacture, protection of the electrical components, and ease of testing which are afforded by the switch assembly described in the aforesaid specification No. 2036541 A.

According to the present invention there is provided a switch means for use with an electrical immersion heater having a head adapted to be secured to the wall of a vessel for heating liquids, wherein the switch means comprises a steam responsive mechanism mounted on a body to form a first assembly, and a second assembly comprising a dry overload responsive actuating mechanism and a carrier member on which are mounted live and neutral electrical supply connectors, switch contacts, and conductors to connect electrically the connectors and the switch contacts with cold tails of the immersion heater; wherein the second assembly is securable to the head of the immersion heater so that a switch actuating member protrudes from the second assembly; and wherein the first assembly is securable to the head independently of the second assembly by clamping means; wherein the clamping means is arranged to allow the first assembly to be rotated or moved arcuately relative to the head and the second assembly prior to being secured non-rotatably to the head; and wherein a part of the steam responsive mechanism extends to cooperate with the switch actuating member so as to be effective to open said contacts, when the steam responsive mechanism is subjected to steam, when the said part and actuating member are in predetermined mutually relative positions and in relative positions adjacent to said predetermined relative positions.

The clamping means preferably comprises a clamping member arranged to engage the head, for clamping the head to the wall of the vessel around an aperture provided in the wall to receive the head.

The invention also provides heater apparatus comprising the switch means of the invention and an electrical immersion heater, wherein the immersion heater comprises a heating element secured to a head so that cold tails of the element extend through a main panel of the head; wherein the head is provided with an externally threaded cylindrical portion and a peripheral flange around a junction between the main panel and the cylindrical portion; and wherein said main panel has fastener means clamping the second assembly to the main panel.

The clamping member preferably comprises an internally threaded member engageable around the cylindrical portion, which internally threaded member is provided with an external flange or flanges engageable by an abutment member or abutment members secured to the body by a plurality of fasteners.

Alternatively, head clamp means, comprising a clamping member, may be provided to secure the head to the vessel wall independently of the clamping means, the clamping means comprising a slotted abutment or abutments provided on the body and a plurality of fasteners adjustably located in the slots for securing the abutment or abutments to mountings provided on the head.

The invention also provides a method assembling a vessel so as to incorporate the heater apparatus, which method includes the steps of fastening the second assembly to the main panel, inserting the immersion heater and second assembly into the vessel and inserting the cylindrical portion through a lower aperture in the wall of the vessel, locating the clamping member on the cylindrical portion and actuating the clamping member to clamp the wall between the flange and the clamping member so that a main part of the element lies in a plane parallel or nearly parallel with a bottom of the vessel; locating the body in a desired position relative to a steam vent or hold in an upper part of said wall, and tightening said plurality of fasteners to clamp the body non-rotatably in the desired position.

It will be readily appreciated that the invention avoids the necessity to align the element with extreme accuracy so as to enable the element to be fitted rapidly to the vessel without requiring the use of jigs or expensive means for aligning the elements, and enables the body to be located accurately and rapidly so as to be correctly aligned with the steam vent or hole. The correct alignment of the body also facilitates the fitting of an outer cover, which latter may form part of or may engage a handle of the vessel.

Also, as compared with known switch assemblies in which the steam responsive mechanism is mounted on a moulding which carries the electrical components and the dry overload responsive actuating mechanism or which is clamped to or mounted on a member carrying the electrical components and the dry overload responsive actuating mechanism, the whole of the second assembly in the present invention is protected from working loads, shocks and forces applied to the body either directly or via the cover or handle, so as to improve the reliability of the switch means, and in particular the long term effectiveness of the dry overload responsive actuating mechanism.Furthermore, an effective seal can be provided between the clamping means and the second assembly, and the design and production of the carrier member is simplified by the invention relieving the carrier member of the need to register accurately with and provide mechanical support for the body.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein: Figure 1 shows a vertical section through a portion of a vessel in the form of an electric kettle provided with heater apparatus including switch means, in accordance with the invention; Figure 2 shows the switch means in rear elevation; Figure 3 shows a horizontal section through the heater apparatus, corresponding to the line Ill-Ill in Figure 1; Figure 4 shows an internal part of the switch means in front elevation; Figure 5 shows a cross-section through part of the heater apparatus on a line corresponding to the line V-V in Figure 4; and Figures 6, 7 and 8 are views similar to Figures 1, 2 and 3 showing a modified form of the heater apparatus.

The electric kettle body has a wail 10 and is provided with a handle 11, an immersion heater 12, an earth pin connector 1 3 and switch means.

The switch means comprises a second assembly including a dry overload responsive mechanism 14, and an electrical connector and switch arrangement 16, and a first assembly comprising a steam responsive actuating mechanism 1 8. The switch means is provided with a cover 1 5 or housing.

The immersion heater 12 comprises an element 20 having a metal sheath 21; a metal head having a main panel 22, a peripheral rim flange 23 and an externally threaded cylindrical portion 24 perpendicular to the main panel; and an elongate post arrangement. The elongate post arrangement comprises a first post 25 which is secured perpendicularly to the main panel above a central axis 26 of the head, and a longer second post 27 secured to the main panel so as to be parallel with and slightly above the post 25. The free end parts of the posts are internally threaded to receive two fasteners 30 one of which clamps the earth pin connector 1 3 directly to the post 27.The ends of the sheath 21 are secured to the main panel so as to leave cold tails 28 of the element projecting into a socket defined by the cylindrical portion 24 and the main panel 22, and an intermediate portion of the sheath is secured across one face of the main panel to provide a hot spot 29.

The immersion heater 1 2 is secured in a predetermined position in the body by an internally threaded clamping member 31 which is screwed onto the portion 24 so as to clamp the rim 23 and a seal 32 to the wall 10. The second assembly is secured in the socket prior to the immersion heater being fitted to the kettle.

In the second assembly the dry overload responsive mechanism 1 4 comprises a moulded member 40 of a heat resistant thermal insulating material, a bimetal 41 of stressed snap-acting dished form located on one side of the member 40 by a cylindrical flanged metal retainer 42, and a push rod 43 which extends perpendicularly from the bimetal through a cylindrical guideway through the member 40 to project from the other side of the member 40. The member 40 is apertured to provide passages through which the posts 25 and 27 and cold tails 28 extend, and to receive projections or pegs 60 of the switch arrangement 16.Said one side of the member 40 provides a flat abutment face 44 which confronts and abuts the main panel 22, and is shaped to allow the bimetal to snap from a convex dished form to a concave dished form, upon being heated to a predetermined temperature by the hot spot 29, to thrust the push rod 43 away from the hot spot.

The electrical connector and switch arrangement 16 comprises a carrier member 61 together with a set of switch contacts, and electrical connectors which are arranged on the mounting as shown in Figures 3, 4 and 5. The connectors comprise a live electrical supply connector terminal pin 62, and a similar neutral pin 63. The pin 62 extends through the carrier member and is rivetted over to secure one end of a first spring connector 64 to an inside face 65 of the carrier member. Said one end is further held by a projection 66 of the carrier member. The neutral pin 63 similarly extends through the carrier member and is rivetted over to secure a neutral connector 67 to the carrier member which neutral connector has an extension which is clamped to one of the cold tails 28 by a cylindrical collar 68.A second spring connector 69 is secured to the inside face by two projections 70, and similarly has an extension which is secured to the other cold tail by a further collar 68. The set of switch contacts comprises a first contact 71 mounted on a free end of the connector 64 and a second contact 72 mounted on a free portion of the second spring connector 69.

The first connector 64 is arranged as shown in Figure 5 so that it can be displaced by the push rod 43 to move the first contact away from the main panel so as to open the contacts, and the second spring connector 69 has an extension 73 which can be moved by an actuating member in the form of a second push rod 74 in a direction towards the main panel so as to open the contacts.

The spring connectors 64 and 69 are arranged so that when the first contact 71 is moved outwards away from the head, the second contact is prevented from following the first contact for more than a slight distance by the extension 73 abutting either the push rod 74 or the mounting adjacent the push rod; and similarly when the second contact is moved inwards towards the head, any movement of the first contact is restricted by the connector 64 abutting the push rod 43, or optionally an extension 45 of the moulded member 40 (shown in broken lines in Figure 5). Furthermore the contacts are caused to wipe across each other slightly during the initial part of each opening movement and the finai part of each closing movement, so as to be self cleaning.

The inside face of the carrier member and the other side of the moulded member 40 are shaped to interengage and define therebetween a switch contact chamber 75, and the projections 60 are provided with terminal heads, after assembly, to secure together the carrier member and the moulded member 40. The peripheral surfaces of the member 40 and an adjacent portion of the carrier member 61 are shaped so as to be a close sliding fit in the socket, and the outside face of the carrier member is provided with a recess 77 and an abutment 76 which enables the carrier member and member 40 to be clamped to the head by the second of the two fasteners 30, independently of the earth pin connector 1 3 which is partially accommodated in said recess.

The second push rod 74 of stepped cylindrical form extends through a stepped cylindrical way in the carrier member. A plug socket 52 is provided to receive an electrical supply connector (not shown), for connecting to the pins 13, 62 and 63, which pins extend from the carrier member through a wall of a plastics member 55 having an extension 53 which defines the socket 52. The plastics member 55 is secured to the rear or outside face of the carrier member, e.g. by a screw or screws, and is provided with an aperture for the thrust rod 74.

The plastics member 55 has an inwardly or forwardly directed annular peripheral flange 56 which engages in a peripheral rebate in the rear of the carrier member. The clamping member 31 is internally grooved to receive a sealing ring 51 which engages a plain peripheral portion of the external surface of the flange 56.

In the first assembly the steam responsive mechanism 1 8 is mounted on a body 80, and comprises a lever 81 and a steam actuable bimetal 82. The body 80 has an upper portion 83 which extends upwards from adjacent the clamping member 31 so as to confront the wall 10 of the kettle body to define a steam space 84 therebetween. The bimetal 82 is mounted, at its upper end, on a top part of the upper portion 83 so as to depend within the steam space alongside that side of the upper portion which confronts the wall 10. The lever 81 is pivotally mounted, on a pivot 91 on the body, so as to have an upper portion 85 which lies alongside the other side of the upper portion 83, and a top part of the portion 85 is engaged by a spring 86.The spring is located by the top part of the body, and is arranged so that the lever 81 is movable between a first stable position, in which an abutment 87 of the lever abuts the upper portion 83, and a second stable position, in which the abutment 87 is spaced apart from the upper portion 83. The lever has a lower part 88 which in the first position is spaced apart from the second push rod 74, and in the second position abuts the push rod so as to hold the contacts 72 away from the contact 71 and further abuts a lower portion 89 of the body.

The upper portion 85 is shaped to provide a knob 90 which projects through the cover 1 5 to allow the lever to be moved manually to the first position.

The spring 86 is of round wire formed to S or Z shape so as to have top and bottom parallel limbs which are self centring in V or U shaped confronting grooves in the top parts of the body and lever, which limbs are connected by an intermediate transverse limb, and the arrangement is such that the compression on the spring is increased to a maximum when the lever is in an intermediate position between the first and second positions so as to urge the lever out of said intermediate position.

The wall 10 has an upper steam vent or hole 33 which allows steam to pass from the kettle into the steam space 84 so as to heat the bimetal 82, whereby to cause the bimetal to bend outwards away from the wall 10 to contact an abutment 92 on the upper portion 85, which abutment extends through an aperture in the upper portion 83 into the steam space, so that the movement of the bimetal is transmitted to the lever to cause the lever to move to the second position via an unstable intermediate position.

A lower portion 93 of the body is of ring form and is provided with a forwardly directed annular abutment surface which is adapted to be clamped to an annular abutment face on a rear end portion 34 of the clamping member 31.

The clamping member 31 forms part of clamping means, which means further comprises an abutment member in the form of an internally flanged clamp ring 35 and clamping fasteners 36 (which are shown misplaced in Figure 3 to appear in the section). The portion 34 extends to within the ring and is externally flanged to cooperate with the internal flange of the clamp ring 35, and the fasteners 36 extend through the portion 93 into the ring 35 so as to be capable of being tightened to draw the ring 35 towards the portion 93 whereby to thrust the abutment surface towards and against the abutment face.

The cover 15 is mounted on the body 80 by means of fasteners 57 received in sockets 58 adjacent the upper and lower ends of the body, and the cover 15 has an upper end portion 58A which fits into a recess 59 in the handle 11 to conceal a fastener 36 used to secure an end of the handle and a baffle 37 to the kettle wall 10.

The vessel is assembled by assembling, and separately testing, the immersion heater, the first assembly and the second assembly. The second assembly is then inserted into the head of the immersion heater and the earth pin is inserted and secured in place. The plastics member 55 is then secured in position. The immersion heater together with the second assembly is then inserted into the kettle via the opening for the lid of the kettle, and the rear parts of the second assembly and the cylindrical portion 24 of the head are inserted through the lower aperture in the wall 10 until the seal 32 abuts the wall around the aperture.

The element is then held so that the major part of the heating portion of the element lies in a plane which is substantially parallel to the bottom of the kettle, and the head is secured to the wall by means of the threaded clamping member 31, after the sealing ring 51 has been inserted into the clamping member, and after the clamp ring has been located around the clamping member 31.

The immersion heater and second assembly may be tested together as a unit prior to the unit being inserted into the kettle.

At this stage in the assembly the element is secured in a predetermined position, or in a position which is angularly close to the predetermined position, and the interior of the kettle can be inspected visually to ascertain whether or not the positioning of the element is acceptable.

Thereafter the first assembly is located so that the abutment surface on the lower portion 93 confronts the abutment face on the rear end portion 34 of the clamping member, and is then held whilst the clamping fasteners 36 are inserted into the clamp ring 35. The fasteners are then tightened until the clamping means supports the first assembly in such a manner that the first assembly and clamp ring 35 can be moved arcuately relative to the clamping member to allow the upper portion 83 of the body to be moved precisely into a predetermined position relative to the steam vent or hole. The clamping fasteners 36 are then fully tightened so that the clamping means secures the first assembly rigidly to the head of the immersion heater and to the wall 10 around the aperture. The cover 15 is then located in position and secured by means of the fasteners 57 to the body 80.

To assist in the aligning of the first assembly, the top part of the portion 83 preferably extends so as to be locatable in the recess 59 in the handle, or to adjacent the fasteners 36, so that the handle or the fastener can be used as a reference point during the arcuate movement of the first assembly about an axis passing centrally through the head some considerable distance below said top part.

In use any knocks or bumps applied to the cover 15, and the shock loads generated by the operation of the steam responsive mechanism are transmitted directly to the wall of the vessel without being imparted to the second assembly except for the loads applied by the part 88 to the second push rod 74. Furthermore any steam, water or condensate draining down from the steam space 84 will be allowed to drain away around the clamping member 31 and will be prevented from entering the second assembly by the sealing ring 51 and the plastics member 55.

Furthermore, the part 88 has a considerable area which is available for abutting the push rod 74, which area extends in an arc about the axis, so that the part 88 can cooperate with the push rod not only when said first and second assemblies are in their predetermined positions, but also when the second assembly is in a position which is displaced by several degrees of arc around said axis away from said predetermined position so that the positioning of the element is no longer critical.

Referring to Figures 6 to 8, the second embodiment of heater apparatus shown therein is similar to the first embodiment, and in these figures the same reference numbers are given to parts which are identical to the same parts shown in Figures 1 to 5 and are not hereinafter described, whereas modified parts which are similar or equivalent to parts shown in Figures 1 to 5 are indicated by the same reference numbers with the suffix B. Some of the parts common to both embodiments are omitted from Figures 6 to 8.

The second embodiment differs from the first embodiment firstly in the form of the clamping means, and secondly in the form of the plug socket and sealing means.

The clamping means comprises two clamping fasteners 36B which extend through slots 100 in the lower portion 93B of the body 80B, so as to engage in a pair of pillars 101 mounted on the main panel 22. The slots 100 and pillars 101 are equidistant from the axis 26 and the slots extend arcuately relative to the axis. The free ends 102 of the pillars project from the second assembly to provide rearwardly presented abutment faces to which an abutment surface 103 is held by the fasteners 36B. Optionally, washers may be interposed between the abutment faces and surface 103.

The clamping member 31 B serves as head clamp means to clamp the flange 23 and ring 32 to the wall 10 independently of the clamping means. The clamping member 31 B is stepped externally to receive a sealing ring 51B which ring engages an inside surface of a forwardly directed annular extension 106 of the lower portion 93B to provide a seal between the clamping member 31 B and the body 80B around the second assembly.

In the second assembly the members 40 and 61 are apertured to accept the pillars 101.

An arcuately extending way 104 is provided in the lower portion 93B to accept the second push rod 74, which push rod is not stepped so that it is slidably insertable into the second assembly.

The arcuately extending way 104 and slots 100 enable the body 80B to be moved arcuately about the axis when the fasteners 36B are released partially or are not tightened.

The second assembly, in this embodiment, is not provided with the plastics member 55, because the body 80B is adapted to serve as a cover for the second assembly. The plug socket 52 is moulded into the lower portion 93B, which is provided with enlarged apertures 105 to accept the pins 13, 62 and 63, to allow the body to be rotated relative to the pins.

Alternatively, the plug socket may be provided in a separate moulding which is clamped to the body 80B by fasteners e.g. the fasteners 36B to clamp the moulded member in a predetermined position relative to the pins whilst allowing the body to be moved arcuately as hereinbefore described.

The invention is not confined to the precise details of the foregoing examples, and many variations are possible. In the first embodiment, the internal diameter of the lower portion 93 of the body may be increased, and the lever 81 and pivot 91 arranged so as to enable the lower 81 to be removed, whereby to enable the second assembly to be removed from the head without releasing the fasteners 36, or altering the position of the body. The clamp ring 35 could be split and chamfered at its front end so as to be capable of being assembled together with the first assembly, during assembly of the first assembly, and subsequently pushed over the clamping member after the clamping member has been tightened to secure the element head in place.Alternatively the external flange on the clamping member could be interrupted, and the internal flange on the clamp ring could likewise be interrupted so that in a particular mutual orientation the clamping member can be inserted with its abutment face foremost in the direction of movement into the clamp ring 35.

It is also possible to substitute a plurality of flanged clamping members, each of limited length, in place of the clamp ring 35.

Furthermore, the bottom fastener 57 may be arranged so as to extend through the lower portion 93 into the clamp ring 35, so that the fastener 57 serves also as a clamping fastener.

If desired, the plastics member 55 can be mounted on the first assembly and provided with enlarged apertures for the pins and the push rod 74. In this variation a sealing member is applied to the second assembly so as to protect the rear face of the carrier member, and this sealing member may carry the sealing ring 51 or be provided with a peripheral portion which serves as the sealing ring 51, there being a space provided between the sealing member and the wall of the socket 52 to provide a drainage path for any water which passes rearwardly across the clamping means, and a drainage way may be provided in the bottom part of the lower portion 93.

In both embodiments, the earth pin may be formed as part of the head instead of being secured to a post on the head, but the arrangement of the earth pin described is preferred because the earth pin is used to centralise the plug socket connector as the latter is inserted into the plug socket.

In the second embodiment the pillars 101 may be replaced by other forms of mountings to which the lower portion 93 may be secured.

Claims (13)

1. Heater apparatus comprising switch means and an electrical immersion heater, wherein the electrical immersion heater comprises a sheathed heating element secured to a main panel of a head so that cold tails of the element extend through the main panel; wherein the switch means comprises a steam responsive mechanism mounted on a body to form a first assembly, and a second assembly comprising a dry overload responsive actuating mechanism and a carrier member on which are mounted live and neutral electrical supply connectors, switch contacts, and conductors connecting electrically the connectors and the switch contacts with the cold tails of the immersion heater; wherein the second assembly is secured to the head of the immersion heater and supports an actuator member; and wherein the first assembly is connected to the head independently of the second assembly by clamping means; wherein the clamping means is arranged to allow the first assembly to be rotated or moved arcuately relative to the head and is actuated to secure the first assembly nonrotatably to the head; and wherein a part of the steam responsive mechanism extends to cooperate with the switch actuating member so as to be effective to open said contacts, when the steam responsive mechanism is subjected to steam, when the said part and actuating member are in predetermined mutually relative positions and in relative positions adjacent to said predetermined relative positions.

2. Apparatus as claimed in Claim 1, wherein said head comprises an externally threaded cylindrical portion extending from the main panel; and wherein an internally threaded clamping member is engaged on said cylindrical portion.

3. Apparatus as claimed in Claim 2, wherein said clamping member forms part of said clamping means and is releasably connected to said first assembly.

4. Apparatus as claimed in Claim 3, wherein said clamping means comprises at least one abutment member secured to the body by fasteners and arranged to engage an external flange on said clamping member

5. Apparatus as claimed in Claim 4, wherein said abutment member is in the form of an internally flanged clamp ring.

6. Apparatus as claimed in Claim 1 or 2, wherein said clamping means comprises at least one mounting provided on the head and a fastener to secure said body to said mounting.

7. Apparatus as claimed in Claim 6, wherein a plurality of said mountings are provided; and wherein said fasteners are adjustably located in slots in said body to secure said mountings to an abutment or abutments provided on said body.

8. Apparatus as claimed in any preceding claim, wherein the switch actuating member is a push rod; wherein the steam responsive mechanism comprises a lever pivotally mounted on the body; and wherein said lever has a lower part which is arranged to actuate said push rod in any of said relative positions.

9. Apparatus as claimed in any preceding claim, wherein a seal is provided to prevent water entering between said first and second assemblies.

10. Apparatus substantially as hereinbefore described with reference to Figures 1 to 3, or Figures 1 to 5, or Figures 6, 7 and 8 of the accompanying drawings.

11. A vessel for heating liquids comprising a hollow body to which is fitted apparatus as claimed in any one of Claims 1 to 9 so that the sheathed element lies inside the hollow body and the first assembly lies outside the hollow body whereby to define a steam space between said body and said hollow body above said head and second assembly.

12. A vessel for heating liquids substantially as hereinbefore described with reference to Figures 1 to 3, or Figures 1 to 5, or Figures 6, 7 and 8 of the accompanying drawings.

13. A method of assembling a vessel for heating liquids so as to incorporate heater apparatus as claimed in any one of Claims 1 to 10, wherein the second assembly is fastened to the head and the head is clamped to a wall of the vessel so as to close an aperture in said wall through which the second assembly extends and so as to locate the sheathed heating element in position within the vessel; wherein the first assembly is thereafter connected by said clamping means to said head, is moved arcuately relative to said head to bring the body into position relative to a steam vent provided in said wall or a handle provided on said vessel; and wherein said clamping means is further actuated to secure said body in said position.