GB2341666A

GB2341666A - A heat exchanger for an instantaneous water heater using a clamp to seal a lid to a can

Info

Publication number: GB2341666A
Application number: GB9820367A
Authority: GB
Inventors: Robert Meadows
Original assignee: Kohler Mira Ltd
Current assignee: Kohler Mira Ltd
Priority date: 1998-09-19
Filing date: 1998-09-19
Publication date: 2000-03-22
Anticipated expiration: 2018-09-19
Also published as: GB2341666B; GB9820367D0

Abstract

A heat exchanger for an instantaneous water heater has a can 1 and a lid 2 carrying one or more heating elements 5, a seal 9 between the lid and the can and a clamp for securing the lid and the case together. The lid may be formed from metal and the can (eg. a tank) may be formed from plastics. The lid may feature a rim 9 forming a downwardly open annular channel 10 in which the upper end of the can may be received, a collar 13 fits over the top of the rim 9 and a shoulder 14 in the wall of the can 1 to secure the lid 2 to the can 1. The end of the can within the channel 10 may have a rebate 11 on the outside in which an O-ring 12 is seated to form a seal between the can and the lid. The collar may be formed in two halves with respective one ends being secured together when the collar is closed around the assembled can and lid. One half of the collar may be incorporated into the plastics can of a chassis of an instantaneous water heater.

Description

2341666) IMPROVEMENTS IN OR RELATING TO INSTANTANEOUS WATER HEATERS This

invention concerns improvements in or relating to instantaneous water 5 heaters.

Instantaneous electric water heaters provide a source of hot water on demand for a variety of applications including ablutionary installations such as showers. The water is heated as it flows through a heat exchanger containing one or more electric heating elements and, for a given power 1 input, the water temperature is controlled by adjusting the flow rate.

Heat exchangers are known having heating elements soldered onto a lid that is secured to one end of a can through which the water flows. Problems can arise in securing the lid to withstand the water pressures that can arise in use, especially when the lid and can are made ofl different materials.

The present invention has for its object to provide a heat exchanger for an instantaneous water heater in which the lid is secured to the can in watertight fashion.

1 It is further preferred object of the present invention to provide a heat exchanger for an instantaneous water heater in which lid and can are made of different materials.

According to the present invention there is provided a heat exchanger for an instantaneous water heater comprising a can, a lid at one end of the can, the lid supporting one or more heating elements received in the can and adapted to be connected to an electrical supply externally of the can, a seal between 10 the can and lid, and a clamp for securing the can and lid together.

2 Preferably, the can is made of plastics and the lid is made of metal to which the or each heating element is attached by soldering or other suitable means.

1 Advantageously, the lid has a raised rim providing a channel open to the underside in which the end of the can is received and retained by the clamp with the seal being provided between the can and the lid within the channel- c In this way, the rim provides reinforcement for the end of the can.

Preferably, the seal is positioned on the outside of the can. As a result, the seal is squeezed between the can and the rim if the can is deflected by water pressure to improve the seal therebetween. Also, the can is prevented from being pushed in and reducing the squeeze on the sealAdvantageously, the clamp fits over the rim of the lid and under a shoulder on the outside of the can to secure the can and lid together. In this way, the interface between the can and lid is concealed and axial separation of the can and lid is prevented.

Preferably, the clamp is in the form of an external collar of channelsection split into two halves. As a result, the collar can be closed around the assembled can and lid to fit over the top of the rim and under the shoulder. For example, respective ends of the two halves may be hinged together with the other free ends being secured together when the collar is closed.

Alternatively, the halves may be separate and secured together at both ends when the collar is closed. One half of the collar may be formed in the plastic case of the chassis of an instantaneous electric water heater for assembly and mounting of the heat exchanger in the case.

The invention will now be described in more detail by way of example only with reference to the accompanying drawings wherein:- Figure 1 is a side view of a heat exchanger embodying the invention.

C 1 Figure is a half-section through the end of the heat exchanger showing the seal and clampI and Figure 3 is a section showing a detail of the clamp.

Referrine, to the drawinas, there is shown a heat exchanger comprising a W CW 0 plastics can 1 closed at the top by a metal lid 2. - The can 1 has a water inlet 3 in the side near the bottom and a water outlet 4 extending within the can 1 from the top and exiting at the bottom.

C The lid 2 has two electric heating elements 5,6 soldered onto it for reception in the can 1 with terminals 7,8 for connection to an electrical supply (not shown) externally of the can 1.

The lid 2 has a raised rim 9 forming an annular channel 10 opening to the underside of the lid 2 in which the end of the can 1 is received. The end of the can 1 is a close fit in the channel 10 and has an rebate 11 on the outside in which an 0-ring 12 is located to form a seal between the can 1 and the lid 2 within the channel 10.

The lid 2 is secured around the rim 9 to the end of the can 1 by an external collar 13 of channel-section which fits over the top of the rim 9 and under a shoulder 14 formed by an annular flange 15 on the outside of the can 1 below the rebate 11 to clamp the lid 2 on the can 1. The collar 13) is split 4 into two halves 16a, 16b for fitting around the outside of the assembled can 1 and lid 2. Each half 16a, 16b has a tab 17 at one end and an opening 18 at the other end allowing adjacent ends to be coupled to- ether by engaging a 1:1 0 Z:1 C) tab 17 at the end of one half in an opening 18 in the end of the other half. 5 As will be appreciated, assembly of the heat exchanger is simple with the arrangement of the 0-ring 12 and clamp 13 ensuring that an effective watertight seal is obtained between the can 1 and lid 2 without the use of mastic sealants or the like. Furthermore, the position of the 0-ring 12 is such that, if the wall of the can 1 is deflected outwards by the water pressure, the 0ring 12 is squeezed improving the seal between the can 1 and lid 2. Also, the potential risk of leakage occurring if -the wall, of the can 1 is pushed in to reduce the squeeze on the 0-ring 12 is prevented by the location of the end of the can 1 in the channel 10.

Claims

1 A heat exchanger for an instantaneous water heater comprising a can, a lid at one end of the can, the lid supporting one or more heating elements received in the can and adapted to be connected to an electrical supply externally of the can, a seal between the can and lid, and a clamp for securing the can and lid together.

2. A heat exchanger according to claim 1 wherein the can is made of plastics and the lid is made of metal to which the or each heating element is attached by soldering or other suitable means.

3. A heat exchanger according to claim 1 or claim 2 wherein the lid has a raised rim providing a channel open to the underside in which the end of the can is received and retained by the clamp with the seal being provided between the can and the lid within the channel.

4. A heat exchanger according to claim 3 wherein the seal is positioned on the outside of the can.

5. A heat exchanger according to claim 4 wherein the can has an rebate on the outside for locating the seal.

6. A heat exchanger according to any one of claims 3 to 5 wherein the clamp fits over the rim of the lid and under a shoulder on the outside of the can to secure the can and lid together.

7. A heat exchanorer according to claim 6 wherein the clamp is in the t> form of an external collar of channel-section adapted to be closed around 6 the assembled can and lid to fit over the top of the rim and under the shoulder.

8. A heat exchanger according to claim 7 wherein the collar is formed in two halves with respective one ends of the two halves hinged together and the other free ends being secured together when the collar is closed around the assembled can and lid.

9. A heat exchanger according to claim 7 wherein collar is formed in two halves that are separate and secured together at both ends when the collar is closed around the assembled can and lid.

10. A heat exchanger according to claim 9 wherein one half of the collar is incorporated in a plastic case of a chassis of an instantaneous electric water heater for assembly and mounting of the heat exchanger in the case.

11. A heat exchanger according to any one of the preceding claims wherein the seal comprises an 0-ring.

12. A heat exchanger for an instantaneous water heater substantially as hereinbefore described with reference to the accompanying drawings.

13. An instantaneous water heater provided with a heat exchanger according to any one of the preceding claims.