GB2277981A

GB2277981A - Waterheating installations

Info

Publication number: GB2277981A
Application number: GB9309792A
Authority: GB
Inventors: Richard Martyn Griffiths
Original assignee: IMI RANGE Ltd
Current assignee: IMI RANGE Ltd
Priority date: 1993-05-12
Filing date: 1993-05-12
Publication date: 1994-11-16
Anticipated expiration: 2013-05-12
Also published as: GB9309792D0; GB2277981B

Abstract

In an unvented storage waterheater installation including an expansion relief valve 8, the outlet of the relief valve 8 is connected by a pipe 10 to a point of use, such as a W C cistern 17 in which water discharged by the relief valve 8 is subsequently used, thereby avoiding "waste of water". In a first alternative (see Figure 2, not shown) the point of use is a small storage cistern connected to a bath or basin. In a second alternative (see Figure 3) the point of use is a small tank connected via a non-return valve to the main supply pipe for the tank and the waterheater. <IMAGE>

Description

Waterheating Installations This invention relates to waterheating installations, more particularly to so-called unvented waterheating installations in which stored secondary (ie useable) hot water is conveyed to points of use, such as baths, basins, sinks and showers, at mains, or regulated mains, pressure.

Traditionally in the United Kingdom, waterheating installations, especially domestic waterheating installations, have been of the vented, low pressure cistern-fed type. Those systems have a number of disadvantages, principally that it is necessary to provide a cold water feed cistern, which usually is situated in a loft. Accordingly, there has in recent years been a move towards the use of unvented installations, of which our TRIBUNE unit (TRIBUNE is a registered trade mark) is an example, wherein the heated water is conveyed to its points of use by mains, or regulated mains, pressure cold water rather than by relatively low pressure cistern-fed water.

As is well-known, unvented installations in the UK are currently required to include a number of safety devices including an expansion vessel or the like and an expansion relief valve. The former, so long as it continues to function properly, serves to accommodate thermal expansion of the secondary hot water under static conditions. The latter device serves primarily to relieve excess water pressure that might build up in the system due to such thermal expansion in the event of failure of the expansion vessel or the like. The expansion relief valve will, therefore, normally operate very infrequently if at all and, when it does, the discharged water conventionally goes to waste.

Technically, there is no need to use an expansion vessel or the like since one could rely simply on an expansion relief valve to cope with thermal expansion of the secondary water. However, a considerable quantity of water (typically several litres per day) would then be continually discharged to waste and this is impermissible under current UK regulations as constituting "waste of water".

In accordance with the present invention, in its broadest aspect, an unvented waterheating installation including a secondary hot water expansion relief valve is characterised in that the outlet of the relief valve is connected by a conduit to a point of use for water discharged from the valve.

Accordingly; in an installation of the invention, water discharged from the expansion relief valve will generally find some useful application as distinct from, as hitherto, simply going to waste.

Thus, such an installation may dispense with the need for an expansion vessel or the like, for example a bubble-top expansion space, yet comply with existing UK regulations. However, the invention is equally applicable to unvented installations that do include such an expansion vessel or the like.

By the expression "point of use" we mean a location at which the water is used for some purpose as and when it is discharged from the valve or, alternatively and more usually, a location at which it is stored for subsequent use. Any number of possible uses for the discharged water will occur to the reader, and we mention, by way of example, use thereof for topping up a WC cistern. In that particular example, the WC cistern may include an auxilliary storage vessel for receiving and storing water discharged from the expansion relief valve, any stored water therein being transferred to the main cistern, for example upon flushing of the WC.Thus, for example, the auxilliary storage vessel may comprise a pivotally-mounted tray positioned adjacent to the top of the cistern and which is maintained in a generally horizontal orientation by means of the buoyancy afforded by water in the cistern when at its normal, full level but which will tilt when the WC is flushed and that level falls, thereby discharging water collected in the tray into the cistern.

Alternatively, for example, means may be provided to suck water out of the auxilliary storage vessel into the cistern upon flushing of the WC, for example by virtue of a venturi or siphon arrangement.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings which depict, schematically, various installations constructed in accordance with the invention.

Referring to Figure 1 of the drawings, an unvented storage waterheater comprises, as is well known in the art, a lagged cylinder 1, for example of copper or steel, for storing secondary hot water 2 typically at about 60-65 "C. In a domestic context the capacity of the cylinder 1 is usually between 80 and 210 litres, depending on the likely demand for hot water. The secondary hot water 2 is driven to points of use, via an outlet pipe 3 connected to the top of the cylinder 1, by means of mains cold water fed to the base of the cylinder by a pipe 4. The pipe 4 includes a strainer 5, a pressure reducing valve 6, usually set at around 2 bar gauge (ie 3 bar absolute), a non-return valve 7 and an expansion relief valve 8 in the form of a spring-loaded pressure relief valve.

The system further comprises a temperature relief valve 9 whose outlet, together with the outlet of the expansion relief valve, is connected to a pipe 10.

The secondary water 2 may be heated directly, for example by an electric immersion heater 11, but more usually will be indirectly heated by a remote boiler via a coiled heat exchanger 12 located in the cylinder 1, in which case the waterheater additionally includes an energy cut out device 13 that, in the event of the secondary hot water 2 attaining too high a temperature, prevents further heating of the secondary water 2 by closing a motorised valve 14 located in the primary circuit 15. The valve 14 is also actuable by a cylinder thermostat 16, typically set at 60 to 65 OC.

Conventionally, for example in some continental European systems not including an expansion vessel, the outlets of the valves 8 and 9 are connected to waste or where, as in the UK, the installation includes an expansion vessel (not shown) are arranged simply to discharge water to atmosphere in what would be an emergency situation.

In accordance with the invention, however, the pipe 10 serves to convey water discharged, in particular from the expansion relief valve 8, to another point of use, in the Figure 1 arrangement to a WC cistern 17. The cistern 17 is largely conventional, but houses an auxilliary storage vessel in the form of a tray 18 that is pivotally mounted at 19 in such a manner that when the cistern is full, the tray 'floats' in a substantially horizontal orientation and thus serves to store in it water discharged from the valve 8 (and, rarely, the valve 9).The amount of water discharged from the valve 8 over a given time period will, of course, vary in dependance upon the total capacity of the cylinder 1 and the cyclical temperature rises of the water 2, which in turn will depend upon the pattern of use of secondary hot water, but typically will amount to several litres per day in an average household. When, however, the WC is flushed, the tray 18 tilts into a more or less vertical orientation thus discharging its contents into the cistern 17 and it gradually reverts to its normal horizontal position as the cistern 17 is filled up via the valved water inlet 20. Preferably, a delay is built into the tilting action of the tray 18 so that it will not discharge its contents into the cistern 17 until flushing has terminated.

Accordingly, water continually discharged from the valve 8 is put to good use although, of course, excessive discharges may result in some waste via the usual overflow 21 associated with the cistern 17 if the WC is not flushed frequently.

Figure 2 illustrates an alternative use for water continually discharged from the valve 8. Here, a small storage cistern 17', provided with an overflow 21', is connected to a point of use, such as a basin or bath, whereby discharged water may from time to time be drawn off via a tap 22 and therefore put to good use as an auxilliary water supply to that point of use.

In the installation shown in Figure 3, water continually discharged from the valve 8 is stored in a small tank 23 which is connected by a pipe 24, via a non-return valve 25, to the mains supply pipe 4. At the connection between the pipes 4 and 24, the former is, as shown, provided with a restricted bore so as to form a venturi type of arrangement whereby discharged water stored in the tank 23 will be drawn into the pipe 4 each time there is a significant draw off of hot water from the cylinder 1. In this embodiment, therefore, discharged water is effectively recycled within the waterheater.

Claims

CLAIMS:

1. An unvented waterheating installation including a secondary hot water expansion relief valve, characterised in that the outlet of the relief valve is arranged to convey water discharged therefrom to a point of use.

2. An installation according to claim 1 wherein the point of use comprises a vessel for storing said discharged water ready for subsequent use.

3. An installation according to claim 2 wherein said vessel is associated with a W C cistern.

4. An installation according to claim 3 wherein said vessel is located in an upper region of the W C cistern and said discharged water is stored in the vessel and is from time-to-time automatically transferred into the IJ C cistern.

An An installation according to claim 4 wherein said vessel comprises a pivotally-mounted tray normally maintained in a generally horizontal orientation by means of the buoyancy afforded by water in the cistern when in its normal, full condition whereby said discharged water will collect in the tray, the tray being arranged to tilt when the W C is flushed thereby discharging water collected in the tray into the cistern.

6. An installation according to claim 4 including means to suck water from the vessel into the z; C istern when it is flushed.

An n installation according to claim 2 wherein the vessel is connected, via a conduit incorporating a non-return valve, to the cold water feed pipe of the installation in such a manner that said discharged water will be drawn from the vessel into the cold water feed pipe when there is a demand for hot water.

8. An installation according to claim 8 wherein the cold water feed pipe bore is restricted at the point of connection thereto of the conduit whereby said discharged water is drawn into the feed pipe by virtue of a venturi effect.

9. An unvented waterheating installation substantially hereinbefore described with reference to, and as illustrated in, Fig. 1, Figs 1 and 2 or Fig. 3 of the accompanying drawings.

Amendments to the claims have been filed as follows I. An unvented waterheating installation including a secondary hot water expansion relief valve, characterised in that the outlet of the relief valve is arranged to convey water discharged therefrom to a point of use.

4. An installation according to claim 3 wherein said vessel is located in an upper region of the W C cistern and said discharged water is stored in the vessel and is from time-to-time automatically transferred into the W C cistern.

6. An installation according to claim 4 including means to suck water from the vessel into the W C cistern when it is flushed.

7. An installation according to claim 2 wherein the vessel is connected, via a conduit incorporating a non-return valve, to the cold water feed pipe of the installation in such a manner that said discharged water will be drawn from the vessel into the cold water feed pipe when there is a demand for hot water.

8. An installation according to claim 7 wherein the cold water feed pipe bore is restricted at the point of connection thereto of the conduit whereby said discharged water is drawn into the feed pipe by virtue of a venturi effect.