GB2290601A

GB2290601A - Auxiliary heater unit

Info

Publication number: GB2290601A
Application number: GB9507225A
Authority: GB
Inventors: Anthony William Ward
Original assignee: WARDTEC Ltd
Current assignee: WARDTEC Ltd
Priority date: 1994-04-07
Filing date: 1995-04-07
Publication date: 1996-01-03
Anticipated expiration: 2015-04-07
Also published as: IE81013B1; GB9406925D0; GB9507225D0; IE950255A1; GB2290601B

Abstract

An auxiliary heater unit comprises a body defining a chamber 12 for water to be heated and an electrical immersion heater unit 13 permanently mounted on the body at one end thereof with an electrical heating element 15 extending into the body from said one end for heating the water in the body. The permanent mounting 26 may be by welding, soldering or brazing. Hinged cable clamps for the unit are disclosed (Figs. 5 to 7, not shown). <IMAGE>

Description

Title: "Auxiliary Heater Unit" Description of the invention This invention relates to an auxiliary heater unit in or for a central heating system.

Hitherto such an auxiliary heater unit has comprised a body defining a chamber for water to be heated and having an electrical immersion heater unit removably mounted therein. This construction has necessitated that the body be provided with a relatively substantial boss with an internally screw-threaded opening in which the immersion heater is screw-threadedly mounted. This has made the body relatively expensive to manufacture. In addition it has been necessary to provide a standard immersion heater.

An object of the invention is to provide a new and improved auxiliary heater unit preferably one which is more economical to manufacture.

According to one aspect of the present invention, we provide an auxiliary heater unit comprising a body defining a chamber for water to be heated and an electrical immersion heater unit permanently mounted on the body at one end thereof with an electrical heating element extending into the body from said one end for heating the water in the body.

The body may comprise a side wall part which defines an opening at said one end, the opening being closed by an end wall member which is permanently connected to the side wall part and said end wall member carrying said immersion heater element.

The immersion heater element may project into the chamber from one side of the end wall member and have electrical connection means disposed on the other side of the end wall member whereby an electrical power supply can be connected to the element.

The end wall member may also carry a temperature sensing element which projects into the chamber from said one side of the end wall member and a thermostat means on the other side of the end wall member to control the supply of electrical power to the heating element in accordance with the temperature of the water in the chamber.

The end wall member may carry means whereby a cover may be attached to the end wall member to enclose the thermostat means and the electrical connections to the heater element.

The side wall part may be provided, at its other end, with an end closure part which is preferably formed integrally with the side wall part.

However, if desired, the end closure part may be provide by a separate element, such as a cap comprising a generally transversely extending wall part with a peripheral flange adapted to be engaged with the side wall at said other end and permanently connected thereto, for example by a permanent joint such as a welded, braised or soldered joint.

The end closure part may be provided with an outlet port which may be centrally disposed. The side wall part may be provided with an inlet port adjacent said one end of the body.

The end wall member may be permanently connected to the side wall part for example by a permanent joint such as a welded braised or soldered joint.

The side wall part is preferably generally cylindrical.

The end wall member may comprise a transversely extending portion surrounded by a peripheral generally cylindrical portion which extends away from said other end of the side wall part and be adapted to engaged within the side wall part of the body and a generally outwardly extending annular flange, at the free end of the cylindrical portion, adapted to overlie the end of the side wall part of the body. The annular flange may be permanently connected for example by a permanent joint such as a welded, braised or soldered joint to the external surface of the side wall part.

Alternatively, the end member may comprise a transversely extending part with a peripheral generally cylindrical portion which extends towards said other end of the side wall part and within which an end portion of the side wall part is received. The cylindrical portion may be permanently connected to the side wall part by a permanent joint such a welded, braised or soldered joint with the external surface of the side wall part.

Further alternatively, the end wall member may comprise a transversely extending part received on a shoulder provided at said one end of the side wall part, the shoulder may be surrounded by an upwardly extending peripheral generally cylindrical portion within which the transversely extending part is received. The transversely extending part may be permanently connected to the side wall part for example by a permanent joint such as a welded braised or soldered joint between the transversely extending part and the internal surface of the cylindrical portion.

The end wall member may be provided with a cable grip which may be fixed to the end wall member with a suitable fastening means such as a fixing screw or screws.

Where the end wall member has a flange which projects outwardly of the side wall part, the end wall member may be provided with a cable grip and a fixing means for the cable grip may be disposed in said flange outwardly of the side wall part.

Alternatively, a cable grip may be provided, the cable grip having a pair of opposed grooves in which the side walls of a slot provided in a cover are received with an end wall of the slot engaging the upper wall of the cable grip to hold the cable grip in position.

Further alternatively the side wall part has a peripheral inner cylindrical portion within which the end wall part is received, and a fixing means for a cable grip may be disposed between the cylindrical portion and the cable grip.

The side wall part may be made of copper and the end wall member may be made of brass. However, if desired, both of these components may be made in copper or brass and the end closure part may in either case be made of brass or copper. Further alternatively, any one or more of the components previously mentioned may be made of stainless steel.

Because there is no need to provide a boss at said one end of the body, and because the end wall member carriers the immersion heater element, the expense of a separate boss and a separate conventional immersion heater unit are avoided so that the auxiliary heater unit of the present invention is more economical to produce.

Should the immersion heater unit fail, it is simply necessary to replace the old unit, with suitable valve means being provided in the pipe work to the inlet and outlet to facilitate this. In addition, since the heater unit can be tested as a single unit, better quality control can be more easily achieved during manufacture.

According to another aspect of the invention, we provide a hot water system incorporating an auxiliary heater unit according to the first aspect of the invention wherein the hot water system comprises a hot water cylinder having a heating coil or other heating means, a cold water supply pipe and a hot water outlet pipe which may be connected to a vent expansion pipe.

The inlet to the auxiliary heater may be connected to the cold supply pipe cylinder and the outlet may be connected to the hot water outlet pipe.

Alternatively, the inlet to the auxiliary heater may be connected directly to the cylinder and the outlet may be connected to the hot water pipe.

The invention will now be described by way of example with reference to the accompanying drawings wherein: FIGURE 1 is a diagrammatic cross-section through an auxiliary heater unit embodying the invention; FIGURE 2 is a fragmentary cross-section through a modification of the heater unit of Figure 1; FIGURE 3 is a fragmentary diagrammatic cross-section through a further modification of the heater unit of Figure 1; FIGURE 4 is a diagrammatic cross-section through another modification of the auxiliary heater unit of Figures 1 to 3; FIGURE 5 is a diagrammatic perspective view of one form of cable grip for use with the auxiliary heater unit shown in Figure 1; FIGURE 6 is a diagrammatic perspective view of a cable grip for use with the auxiliary heater unit shown in Figure 2;; FIGURE 7 is a diagrammatic perspective view of a cable grip for use with the auxiliary heater unit shown in Figure 3; FIGURE 8 is a diagrammatic illustration of a central heating system incorporating auxiliary heater unit as shown in Figure 1; and FIGURE 9 is a diagrammatic illustration of another central heating system incorporating an auxiliary heater unit shown in Figure 1.

Referring now to Figure 1, an auxiliary heater unit is shown generally at 10 and comprises a body 11 defining a chamber 12 for water to be heated. An electrical immersion heater unit 13 is permanently mounted on the body 11 at one end 14 thereof with an electrical heater element 15 extending into the body 11 from said one end 14 for heating water in the chamber 12.

The body 11 comprises a side wall part 16 which defines an opening 17 at said one end 14, the opening being closed by an end wall member 18 which is permanently connected to the side wall part 16 by a permanent joint 19.

The immersion heater element 15 is carried by the end wall member 18 and projects into the chamber 12 from one side 20 of the end wall member 18 and has electrical connection means 21 disposed on the other side 22 of the end wall member 18 whereby an electrical power supply can be connected to the element.

In the present example, the electrical power supply is connected to the element via the electrical connection 21 through a thermostat 23 disposed on said other side 22 of the end wall member 18 and connected to a temperature sensing element 24 which is carried by the end wall member 18 and projects into the chamber 12 from said one side 20 thereof.

The end wall member 18 comprises a transversely extending portion 25 of generally cylindrical disc shape provided with apertures in which the immersion heater element 15 and temperature sensing element 24 are mounted by a permanent joint 26.

The disc-shaped transversely extending portion 25 is surrounded by a peripheral generally cylindrical portion 27 which is engaged within the side wall part 16 and has a generally outwardly extending annular flange 28 adapted to overlie the end 14 of the side wall part 16 of the body 11. The parts 25,27 and 28 are all formed integral with one another as a pressing in, in the present example, brass although if desired it may be made of any other desirable material such as copper or stainless steel.

A screw-threaded rod 29 is suitably fixed at one end to the transversely extending part 20 to project upwardly therefrom and receives a nut 30 to retain a cover member 31 to the end wall member 18 to enclose the thermostat means 23 and the electrical connections 21.

A cable clamp 32 of the configuration shown in Figure 5 and made of a suitable synthetic plastics material such as nylon is fastened to the end wall member 18 by a screw 33 which extends through an aperture 34 in the flange 28 and is received in a bore 35 in the under surface 36 of the cable clamp 32.

The side wall part 16 at its other end 37, i.e. the end opposite to said one end 14, is provided with an end closure part 38 which in the present example is formed integrally with the side wall part 16 as a pressing in copper or if desired in brass or stainless steel. A tubular boss 39 is fixed communication with in an opening 40 centrally of the end closure part 38 by a permanent joint. The boss 39 provides an outlet for hot water from the chamber 12. The side wall part 16 is provided with a further tubular boss 41 which communicates with an opening 42 in the side wall part 16 and is fastened to the side wall part 16 by a permanent joint 43.

Throughout the specification the term "permanent joint" may, for example, be a welded, braised or soldered joint as appropriate.

Referring now to Figure 2, the same reference numerals have been used as used in Figure 1 to refer to corresponding parts. This embodiment differs from that of Figure 1 in the configuration of the end wall member 18 which in this example comprises a transversely extending part 25 of generally disc shape but having a peripheral generally cylindrical portion 14 which extends towards said other end 37 of the body 11 and is of a diameter that is sufficiently large to receive the outer surface of the side wall part 16 therein. The end wall member 18 is permanently connected to the side wall part 16 by a permanent joint 41 between the flange 14 and the external surface of the side wall part 16.

Because there is no outwardly extending flange corresponding to the flange 28 of the embodiment of Figure 1, an alternatively cable clamp configuration is provided as shown at 42 in Figure 6. This embodiment of cable clamp 42 is provided with a pair of opposed grooves 43 in which side wall parts 44 of a slot in the cover 31 are received with an end wall 45 of the slot engaging the upper wall 46 of the cable grip 42 to hold the cable grip in position.

Referring now to Figure 3, a further alternative configuration of one end 14 of the unit of Figure 1 is illustrated and again the same reference numerals have been used to refer to corresponding parts.

In this embodiment the end wall member 18 comprises only the transversely extending portion 25 of generally disc shape. This portion 25 is received on a shoulder 50 provided by an outwardly extending flange 51 formed integrally with a side wall part 16 and bounded by a cylindrical portion 52 which extends in the direction away from the other end 37. The end wall member 18 is permanently connected to the side wall part 16 by means of a permanent joint 53 provided between the disc part 25 and the internal surface of the cylindrical flange 52.

In this embodiment a cable clamp of the configuration shown at 54 in Figure 7 is provided and the cable clamp is secured in position by means of a screw 55 passing through an opening 56 in the cylindrical portion 52 and received in a bore 57 of the cable clamp 54.

Referring now to Figure 4 an alternative head closure part at the other end 37 of the side wall part 16 is shown. This comprises a cap 60 comprising a generally transversely extending disc-shaped wall part 61 with a peripheral generally cylindrical portion 62 extending towards said one end 14 and surrounding an end part 63 of the side wall part 16 and connected thereto by a permanent joint 64. The disc-shaped part 61 is provided with a boss 39 permanently connected to the disc-shaped part 61 by a permanent joint 65.

Referring now to Figure 6 there is shown part of a hot water system 70 comprising a hot water cylinder 71 of conventional form provided with a heater coil 72 in known manner and provided with a cold water supply pipe 73 from a cold water header tank 74. The cylinder 71 is provided with a hot water supply pipe 75 which extends to a hot water tap 76 and is connected to a vent and expansion pipe 77 in conventional manner. An auxiliary heater unit according to the embodiments previously described is shown at 80 and has its outlet connected to the hot water supply pipe 75 by a pipe 81 and has its inlet connected to the cold water supply pipe 73 by a pipe 82.

Figure 9 illustrates an alternative hot water system, and the same reference numerals have been used to refer to corresponding parts as were used in Figure 8. This embodiment differs from that of Figure 8 in that the inlet to the unit 80 is connected by a pipe 83 to the hot water cylinder 71 itself so that the unit 80 can be supplied with pre-heated water if desired.

The volume of the chamber of the auxiliary heater unit of the present invention is considerably smaller than that of the hot water cylinder 71 and that the relatively small volume of water is heated at any one time so that effectively an instantaneous type heater facility is provided. Typically, the volume of the unit 80 is 1 to 2 litres.

If desired suitable isolating valves, not shown, may be provided in the delivery and supply pipes are connected to the unit 80 so that the unit can be easily removed and replaced if desired.

By carrying the immersion heater and thermostat, when provided, on the end closure member 18, which can be relatively simply connected to the remainder of the unit and made as a simple pressing of relatively lightweight material, the expense and complexity of the structure is reduced compared with the hitherto necessary relatively heavy boss and the need to provide a conventional, bought-in, immersion heater unit.

The features disclosed in the foregoing description, or the accompanying drawing, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS:

1. An auxiliary heater unit comprising a body defining a chamber for water to be heated and an electrical immersion heater unit permanently mounted on the body at one end thereof with an electrical heating element extending into the body from said one end for heating the water in the body.

2. A heater unit according to claim 1 wherein the body comprises a side wall part which defines an opening at said one end, the opening being closed by an end wall member which is permanently connected to the side wall part and said end wall member carrying said immersion heater element.

3. A heater unit according to claim 2 wherein the immersion heater element projects into the chamber from one side of the end wall member and have electrical connection means disposed on the other side of the end wall member whereby an electrical power supply can be connected to the element.

4. A heater unit according to claim 2 or claim 3 wherein the end wall member also carries a temperature sensing element which projects into the chamber from said one side of the end wall member and a thermostat means on the other side of the end wall member to control the supply of electrical power to the heating element in accordance with the temperature of the water in the chamber.

5. A heater unit according to claim 4 wherein the end wall member carries means whereby a cover may be attached to the end wall member to enclose the thermostat means and the electrical connections to the heater element.

6. A heater unit according to any one of claims 2 to 5 wherein the side wall part is provided, at its other end, with an end closure part.

7. A heater unit according to claim 6 wherein the end closure part is formed integrally with the side wall part.

8. A heater unit according to claim 6 wherein the end closure part is provided by a separate element.

9. A heater unit according to claim 8 wherein the end closure part comprises a cap comprising a generally transversely extending wall part with a peripheral flange adapted to be engaged with the side wall at said other end and permanently connected thereto.

10. A heater unit according to claim 9 wherein the permanent connection is by virtue of a permanent joint comprising a welded, braised or soldered joint.

11. A heater unit according to any one of claims 6 to 10 wherein the end closure part is provided with an outlet port.

12. A heater unit according to any one of claims 2 to 11 wherein the side wall part is provided with an inlet port adjacent said one end of the body.

13. A heater unit according to any one of claims 2 to 12 wherein the end wall member is permanently connected to the side wall part.

14. A heater unit according to claim 13 wherein the permanent connection is by virtue of a permanent joint comprising a welded braised or soldered joint.

15. A heater unit according to any one of claims 2 to 14 wherein the side wall part is generally cylindrical.

16. A heater unit according to any one of claims 2 to 15 wherein the end wall member comprises a transversely extending portion surrounded by a peripheral generally cylindrical portion which extends away from said other end of the side wall part and is adapted to be engaged within the side wall part of the body and a generally outwardly extending annular flange, at the free end of the cylindrical portion, adapted to overlie the end of the side wall part of the body.

17. A heater unit according to claim 16 wherein the annular flange is permanently connected to the external surface of the side wall part.

18. A heater unit according to claim 17 wherein the permanent connection is by virtue of a permanent joint comprising a welded, braised or soldered joint.

19. A heater unit according to any one of claims 2 to 15 wherein the end member comprises a transversely extending part with a peripheral generally cylindrical portion which extends towards said other end of the side wall part and within which an end portion of the side wall part is received.

20. A heater unit according to claim 19 wherein the cylindrical portion is permanently connected to the side wall part.

21. A heater unit according to claim 20 wherein the permanent connection is by virtue of a permanent joint comprising a welded, braised or soldered joint with the external surface of the side wall part.

22. A heater unit according to any one of claims 2 to 15 wherein the end wall member comprises a transversely extending part received on a shoulder provided at said one end of the side wall part, the shoulder being surrounded by an upwardly extending peripheral generally cylindrical portion within which the transversely extending part is received.

23. A heater unit according to claim 22 wherein the transversely extending part is permanently connected to the side wall part.

24. A heater unit according to claim 23 wherein the permanent connection is by virtue of a permanent joint comprising a welded braised or soldered joint between the transversely extending part and the internal surface of the cylindrical portion.

25. A heater unit according to any one of claims 2 to 24 wherein the end wall member is provided with a cable grip which is fixed to the end wall member with a suitable fastening means.

26. A heater unit according to any one of claims 16 to 18 wherein the end wall member is provided with a cable grip and a fixing means for the cable grip is disposed in said flange outwardly of the side wall part.

27. A heater unit according to any one of claims 2 to 24 wherein a cable grip may be provided, the cable grip having a pair of opposed grooves in which the side walls of a slot provided in a cover are received with an end wall of the slot engaging the upper wall of the cable grip to hold the cable grip in position.

28. A heater unit according to any one of claims 2 to 24 wherein the side wall part has a peripheral inner cylindrical portion within which the end wall part is receive and a fixing means for a cable grip is disposed between the cylindrical portion and the cable grip.

29. A heater unit according to any one of claims 2 to 28 wherein the side wall part is made of copper and the end wall member is made of brass.

30. A heater unit according to any one of claims 2 to 28 wherein the side wall part of the end wall member are both made in copper or brass

31. A heater unit according to claim 29 or 30 wherein the end closure part is made of brass or copper.

32. A heater unit according to any one of claims 2 to 28 wherein any one or more of the side wall part, end wall member and end closure part is made of stainless steel.

33. A heater unit substantially as hereinbefore described with reference to the accompanying drawings.

34. A hot water system incorporating an auxiliary heater unit according to any one of claims 1 to 33 wherein the hot water system comprises a hot water cylinder having a heating coil or other heating means, a cold water supply pipe and a hot water outlet pipe which may be connected to a vent expansion pipe.

35. A hot water system according to claim 34 wherein the inlet to the auxiliary heater is connected to the cold supply pipe cylinder and the outlet is connected to the hot water outlet pipe.

36. A hot water system according to claim 34 wherein the inlet to the auxiliary heater is connected directly to the cylinder and the outlet is connected to the hot water pipe.

37. A hot water system substantially as hereinbefore described with reference to the accompanying drawings.

38. Any novel feature or novel combination of features described herein an/or in the accompanying drawings.