GB2423347A

GB2423347A - Water supply fitting

Info

Publication number: GB2423347A
Application number: GB0428359A
Authority: GB
Inventors: Nigel Paul Sansum; Richard William Dauncey
Original assignee: Kohler Mira Ltd
Current assignee: Kohler Mira Ltd
Priority date: 2004-12-24
Filing date: 2004-12-24
Publication date: 2006-08-23
Anticipated expiration: 2024-12-24
Also published as: GB2423347B; GB2423347A8; GB0428359D0

Abstract

A water supply fitting such as a mixer valve for mixing hot and cold water has a liner 20 of low thermal conductivity material in the hot water inlet waterway to reduce heat transfer between the water and the external surface of the valve body 6.

Description

IMPROVEMENTS IN OR RELATING TO

WATER SUPPLY SYSTEMS

This invention concerns improvements in or relating to water supply systems. The invention has particular, but not exclusive, application to hot water supply systems and more especially to outlet fittings such as faucets used in such systems.

Many faucets for domestic, commercial and healthcare applications have a metal body. As a result, when used in the hot water supply, the external surface of the faucet can become hot to the touch due to conduction of heat through the body. For example, the temperature of the hot water supply is typically around 60 C and this can result in temperatures of around 55 C at the external surface of the faucet.

This gives rise to a risk of scalding if a user touches the body when the external surface is hot. In fact, it has been shown that surface temperatures above 48 C will result in burns when contacted by human skin. This is a particular problem where faucets are used by young children or elderly adults who may not be aware of the potential risks and may touch the external hot surface of the faucets. It is also a problem for faucets used in healthcare establishments where patients and other users may be scalded by touching the external hot surface of the faucet.

Some types of faucets such as bath/shower mixers incorporating thermostatic mixing valves to blend supplies of hot and cold water to provide a supply of a temperature controlled water have a large external surface area and this can increase the risk of scalding from a user touching the external surface, for example when adjusting the temperature setting of the mixing valve.

It has already been proposed to address these problems by providing faucets with external shrouds that cover the exposed surfaces of the body.

The shrouds are made of plastic or other low thermal conductivity material that does not transmit heat from the body of the faucet and remains cool to the touch. Such shrouds add to costs and can detract from the aesthetic appearance of the faucet.

Other proposals include the use of air gaps within the body of the faucet to reduce heat transfer to the external surface of the body. The provision of air gaps requires special designs that add to costs and do not eliminate entirely heat transfer with the result that external surface of the body can still become hot to the touch if the hot water is run for any length of time or if the faucet is in regular use.

The present invention has been made from a consideration of the forgoing problems and disadvantages and seeks to provide an improved design which overcomes or at least mitigates some or all of the problems of existing faucets outlined above.

According to a first aspect of the invention, there is provided a water supply fitting such as a faucet having a body with an inlet, an outlet and an internal waterway arranged to reduce heat transfer between the body and water in the waterway.

By this invention, the external surface of the body is not heated to any appreciable extent by heat transfer from hot water flowing through the internal waterway. As a result, where the inlet is connected to a supply of hot water, the risk of a user being scalded by touching the external surface of the body is reduced or eliminated.

Typically, the body is made of metal or other material having a high thermal conductivity and the internal waterway comprises a liner of lower thermal conductivity, for example a thermally insulating material such as silicon elastomer or any other plastics material that complies with water supply regulations. In this way, the liner provides a thermal break between the body and the hot water flowing through the waterway.

The liner may be of any size and shape compatible with the body in which it is received. The liner may be in the form of a channel member that is received in an internal waterway formed in the body.

The channel member may be separate from the body, for example a moulding, that can be inserted in and removed from the waterway.

Preferably, the liner provides all or part of the internal waterway in the body.

The faucet may comprise a tap with the liner arranged upstream and/or downstream of a flow control valve to insulate the tap body from hot water flowing through the channel member.

Alternatively, the faucet may comprise a mixer for mixing hot and cold water with the liner arranged upstream of a mixing valve to insulate the faucet body from hot water flowing to the mixing valve.

The liner may be detachable for servicing and/or repair. Alternatively, the liner may be an integral part of the body.

According to a second aspect of the invention, there is provided a method of protecting a user from scalding by touching an external surface of a faucet, the method including providing a faucet having a body with a thermal break between an external surface of the body and an internal waterway to inhibit heat transfer between water in the waterway and the body.

The thermal break may be provided by inserting a liner of thermally insulating material in the waterway to prevent heat transfer between the water and the body. Other arrangements for providing a thermal break may be employed.

The invention will now be described in more detail by way of example only with reference to the accompany drawings wherein:- Figure 1 is a perspective view of a bath/shower mixer embodying the invention; Figure 2 is a perspective view of the body of bath/shower mixer shown in Figure 1; Figure 3 is a section through the body shown in Figure 2 depicting the hot and cold inlet waterways; Figure 4 is a section through the body, similar to Figure 3, with the liner shown in place in the hot inlet waterway; Figure 5 is a section through the body, similar to Figure 4, showing the liner in place in the hot inlet waterway and the body mounted on the inlet manifold with the hot and cold check valves in place between the body and the manifold; Figure 6 is a section through the body and inlet manifold of Figure 5; Figure 7 is a perspective view, to an enlarged scale, of the channel member part of the liner; Figure 8 is a perspective view, to an enlarged scale, of the seal member of the liner; and Figure 9 is a perspective view of the assembled channel member and seal member shown in Figures 7 and 8.

Referring first to Figures 1 and 2 of the drawings, there is shown a bath/shower mixer 1 having inlets 2,3 for connection to supplies of hot and cold water, a bath outlet 4, and a shower outlet 5.

The mixer 1 has a cast metal body 6, for example brass, with a central cylindrical cavity 7 to receive a mixing valve cartridge (not shown) for mixing hot and cold water in accordance with user selection of the desired outlet water temperature via a rotatable control knob 8. The mixing valve cartridge may be a thermostatic or non-thermostatic cartridge.

The body 6 also has a cylindrical recess 9 to receive an on/off flow control and diverter mechanism (not shown) for controlling flow of temperature controlled water from the mixing valve cartridge to a selected one of the outlets 4,5 in accordance with user selection via a control lever 10.

With reference now also to Figures 3 to 9, the mixer 1 has an inlet manifold 11 provided with the inlets 2,3 for connection to incoming supplies of hot and cold water (not shown). The body 6 is mounted on the inlet manifold ii and is provided with internal waterways 12,13 for connection to the inlets 2,3 for delivering hot and cold water to the mixing valve cartridge.

Each waterway 12,13 is provided with a non-return check valve 14,15 to prevent back flow of hot and cold water into the supplies. Each valve 14,15 has a housing 16 with a flange 17 located between the body 6 and manifold 11 and sealed by 0-rings 18,19 received in the body 6 and manifold 11. The housing 16 may be made of plastics or other material having a low thermal conductivity.

The waterway 12 connected to the hot water inlet 2 is also provided with an internal liner 20 for insulating the body 6 from the hot water flowing to the mixing valve cartridge. As best shown in Figures 7 to 9, the liner includes a channel member 21, and seal member 22.

The channel member 21 has an annular inlet 23 and a rectangular outlet 24. The inlet 23 engages an external rebate 25 in the housing 16 of the associated check valve 14 and the outlet 24 is connected to the seal member 22.

The seal member 22 is seated in a recess 26 (Figure 3) in the central cavity 7 and connects the channel member 21 to a hot water inlet (not shown) in the mixing valve cartridge and limits flow back through and around the channel member 21.

The component parts of the liner 20 are made of materials having low thermal conductivity that insulate the cast body 6 from the hot water supply to the mixing valve. In this way, heat transfer from the hot water to the cast body 6 is reduced or eliminated. It will be understood that any suitable low thermal conductivity materials may be used.

In this embodiment, the channel member 21 is a moulding of a low compression set material with a cross-section and aspect ratio to allow sufficient compression and pressure retention to maintain a lifetime seal while allowing the channel member 21 to be removed and replaced so that routine servicing can be carried out. A lubricated grade of silicon elastomer may be used to aid fitting/removal of the channel member 21 although it will be understood that any suitable material may be employed.

The seal member 22 may be made of the same or different grades of the same or different materials as the channel member 21. For some applications, the seal member 22 may be omitted and the channel member 21 designed to provide the required fluid-tight connection to the mixing valve cartridge.

The incoming hot water supply may have a temperature of the order of 60 C and the liner 20 substantially reduces heat transfer from the incoming hot water to the body 6 and prevents the body 6 being heated to a temperature at which the user may be scalded by touching the external surface.

In use, the hot water is mixed with cold water in the cartridge and delivered to the outlet selected by the user at a safe temperature typically of the order of 40 C for showering and 44 C for bath-fill. After mixing with cold water in the cartridge, the temperature of the outlet water is below that at which the user may be scalded and is insufficient to heat the body 6 to a temperature at which scalding may occur. In this way, the user can be protected from scalding throughout the range of outlet water temperatures available for user selection.

As will be appreciated, the insulating effect of the liner 20 helps to reduce heat losses from the hot water within the liner 20 to the surroundings such that the water temperatures may be maintained above 50 C to assist in preventing growth of harmful bacteria such as legionella. In a modification (not shown) some leakage around the channel member 21 may be permitted to enable limited flow of water around the outside of the channel member 22 to aid in stopping bacteria growth.

In this embodiment, the cold-water inlet 3 communicates with the mixing valve cartridge via the waterway 13 in the cast body 6. Heat transfer from the body 6 to the cold water may therefore have a cooling effect on the body 6 and reduce further the effect of heat transfer to the external surface of the body 6 from the outlet water.

In some cases however, it may be desirable to reduce heat transfer from the body 6 to the cold water, for example to prevent condensation forming on the external surface of the body 6. Accordingly, we may also provide the waterway 13 in the body 6 with a liner similar to the liner 20 abovedescribed to insulate the body 6 from the cold water and prevent heat transfer from the body 6 to the cold water.

Although the invention has been described in a faucet having a mixing valve for mixing hot and cold water it will be understood that the invention is not limited to such use and that the invention could be applied to other types of faucet. For example, a tap for hot or cold water could be provided with an insulating flow passage to prevent heat transfer between the tap body and the water delivered to the tap outlet.

Claims

1. A water supply fitting having a body with an inlet, an outlet and an internal waterway arranged to reduce heat transfer between the body and water in the waterway.

2. A water supply fitting according to claim 1 wherein, the internal waterway comprises a liner of lower thermal conductivity than the body.

3. A water supply fitting according to claim 2 wherein, the liner is made of a thermally insulating material.

4. A water supply fitting according to claim 1 or claim 2 wherein, the liner provides a thermal break between the body and water flowing through the waterway.

5. A water supply fitting according to any of claims 2 to 4 wherein the liner has a size and shape compatible with the body.

6. A water supply fitting according to any of claims 2 to 5 wherein the liner is removable.

7. A water supply fitting according to any of claims 2 to 5 wherein the liner is an integral part of the body.

8. A water supply fitting according to any of claims 2 to 7 wherein the liner comprises one or more parts.

9. A water supply fitting according to any of claims 2 to 8 wherein the liner comprises a channel member that is received in the internal waterway.

10. A water supply fitting according to claim 9 wherein the liner further comprises a seal member.

11. A water supply fitting according to any preceding claim comprising a tap with the liner arranged upstream and/or downstream of a flow control valve to insulate the tap body from hot water flowing through the channel member.

12. A water supply fitting according to any of claims 1 to 10 comprising a mixer for mixing hot and cold water with the liner arranged upstream of a mixing valve to insulate the faucet body from hot water flowing to the mixing valve.

13. A method of protecting a user from scalding by touching an external surface of a faucet, the method including providing a faucet having a body with a thermal break between an external surface of the body and an internal waterway to inhibit heat transfer between water in the waterway and the body.

14. A method according to claim 13 wherein the thermal break is provided by inserting a liner of thermally insulating material in the waterway to prevent heat transfer between the water and the body.

15. A water supply fitting substantially as hereinbefore described with reference to the accompanying drawings.