GB2276706A

GB2276706A - Water heating cylinder

Info

Publication number: GB2276706A
Application number: GB9401128A
Authority: GB
Inventors: Liam Flynn
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-25
Filing date: 1994-01-21
Publication date: 1994-10-05
Also published as: GB9401128D0

Abstract

A domestic hot water cylinder is internally divided by a partition (7) of insulating e.g. polystyrene material into communicating upper (10) and lower (11) chambers. Heat exchanger coils (13, 14) and an associated three-way valve (17) allow heating selectively of water in the upper chamber (10) only or in both chambers (10, 11). Each chamber (10, 11) is also provided with an electric immersion heater and a thermostat (20, 21). The valve (17) is motorised. <IMAGE>

Description

A WATER HEATING CYLINDER This invention relates to a water heating cylinder, more particularly a controlled heat transfer coupled cylinder. References in this specification to "cylinder" include domestic hot water tanks of any shape, not necessarily cylindrical.

Water heating cylinders consume considerable amounts of energy.

Therefore, for environmental and economic reasons it is desirable that water heating cylinders heat water as efficiently as possible without wasting energy.

An object of the invention is to provide a water heating cylinder having efficient energy consumption.

According to a first aspect of the invention there is provided a water heating cylinder comprising a fluid tight cylinder, a cold water inlet into the cylinder, a heated water outlet from the cylinder, heating means for heating water within the cylinder and a control means for controlling water heating characterised in that the cylinder has a first water heating chamber and a second water heating chamber and the heating means is disposed within the first and second water heating chambers, the control means being adjustable such that water from the cold water inlet in the first and second chambers can be heated independently, the heated water being dischargeable through the heated water outlet.

Preferably, the first and second water heating chambers are separated by an insulating wall, a communicating pipe being mounted in the wall to facilitate communication between the first and second water heating chambers.

More preferably, the heating means comprises a heating coil.

Suitably, the control means comprises a three-way valve mounted on the heating coil between a first heating coil portion disposed within the first water heating chamber and a second heating coil portion disposed within the second water heating chamber, the three-way valve being adjustable to independently control the first and second heating coil portions.

According to a second aspect of the invention there is provided a fluid tight cylinder, a cold water inlet into the cylinder, a heated water outlet from the cylinder, and heating means for heating water within the cylinder, characterised in that the heating means comprises a heat exchange coil providing two alternative flowpaths through the cylinder, a first flowpath for heating water in the upper part of the cylinder only and a second flowpath for heating water throughout the cylinder, and a valve for directing the heat exchange medium alternatively along one flowpath or the other flowpath.

An embodiment of the invention will now be described having regard to the accompanying drawing in which: Figure 1 is a partial longitudinal cross-section through a water heating cylinder of the invention.

Figure 1 shows a partial cross-section through a water heating cylinder 1 of the invention. As shown in the drawing, a water heating cylinder 1 is cylindrical in shape having a circular bottom wall 3 with a side wall 2 upstanding therefrom and a convex top wall 4. The cylinder 1 is provided with a radially inwardly directed insulating wall 7 which extends radially inwards from the side wall 2. The insulating wall 7 divides the cylinder 1 into an upper chamber 10 between the insulating wall 7 and the top wall 4 and a lower chamber 11 between the insulating wall 7 and the bottom wall 3. Therefore, the cylinder resembles two cylinders, one mounted on top of the other each chamber 10, 11 having side wall portions 2a, 2b respectively.

The insulating wall 7 is suitably made up of a polystyrene material. The insulating wall 7 is defined by a flat upper wall 25 and a concave lower wall 26. The flat upper wall 25 and the lower wall 26 are made from copper. The insulating wall 7 is further provided with insulation vents 24 located between the insulating wall 7 and the side wall 2. The insulation vents 24 serve to provide air release outlets for air trapped in the polystyrene insulating material of the insulating wall 7.

A communicating pipe 9 extends through the insulating wall 7 between the upper chamber 10 and lower chamber 11 to facilitate movement of water between the two chambers 10, 11.

The lower chamber 11 is provided with a first immersion heater base 18 and immersion heater (not shown) mounted thereon while the upper chamber 10 is provided with a second immersion heater base 19 and immersion heater (not shown) mounted thereon. The immersion heater bases 18, 19 are mounted on the side wall 2 and the immersion heaters serve as a back up system for heating water in the water heating cylinder of the invention. The immersion heaters are electrically powered so that water in the upper chamber 10 or the lower chamber 11 can be electrically heated should heating water from a back boiler or other water heating device not be available.

The lower chamber 11 and the upper chamber 10 are also each provided with a lower chamber thermostat 21 and an upper chamber thermostat 20 respectively. The thermostats 20, 21 are mounted on the top wall 4 and side wall 2 respectively and extend inwards through the top wall 4 and side wall 2 into the chambers 10, 11 respectively to monitor the temperature of the heating water within the upper and lower chambers 10, 11.

The side wall 2 is provided with a cold water inlet pipe 5 which opens into the lower chamber 11 adjacent the bottom wall 3 while the top wall 4 is provided with a hot water outlet pipe 6 adjacent the thermostat 20. Water to be heated enters the cylinder 1 through the inlet pipe 5 and exits from the cylinder 1 through the outlet pipe 6.

Heating of the water is effected during passage of water from the inlet 5 to the outlet 6.

Internally, the cylinder 1 is provided with a heating coil 12 employing water as a heat exchange medium. The water heating coil 12 is provided with a hot water inlet pipe 27 at one end and a water outlet pipe 23 at its other end. The hot water inlet pipe 27 extends through the top wall 4 into the upper chamber 10 while the water outlet pipe 23 extends outwards from the cylinder 1 through the side wall 2 adjacent the bottom wall 3. Accordingly, the water heating coil 12 is divided into an upper coil portion 13 located in the upper chamber 10 and a larger lower coil portion 14 in the lower chamber 11. The upper coil portion 13 is connected to the lower coil portion 14 by an outer connecting pipe 16 located on the outside of the cylinder 1 parallel with and adjacent to the side wall 2.The connecting pipe 16 extends through the side wall 2 into the upper chamber 10 and through the side wall 2 into the lower chamber 11 to connect the upper coil portion 13 to the lower coil portion.

The outer pipe 16 is connected to an intermediate side inlet 28 of the lower coil 14 through which hot heating water can enter the lower coil 14 at its top end from the upper coil portion 13. Water exits from the lower coil portion 14 at its bottom end through an outlet 29 and into the return to boiler outlet 23. The return to boiler outlet 23 is provided with a three-way valve 17 also mounted on the outside of the cylinder 1 adjacent the side wall 2. The connecting pipe 16, the side inlet 28 and the outlet 29 are connected to the three way valve 17. The three-way valve 17 controls movement of hot water between the upper coil portion 13 and the lower coil portion 14. This shall be explained more fully below.

The upper coil portion 13 and the lower coil portion 14 are both provided with fins 15 which extend radially outwards from the coil 12 into the upper chamber 10 and lower chamber 11. The fins 15 serve to increase the surface area of contact with water to be heated to enhance heat transfer and ensure a more rapid heating of water within the chambers 10, 11.

The outer surface of the cylinder 1 is encased in an insulating material 22 to further enhance the efficient energy consumption characteristics of the invention.

In use, hot water from a boiler such as a backboiler or other water heating device enters the cylinder through the upper hot water inlet 27 and is passed through the upper coil portion 13 and into the connecting pipe 16. The water is then passed through the side inlet 28 into the lower coil portion 14. The three-way valve 17 is adjusted to an open position so that the water can flow through the return to boiler outlet 23 and is returned to the boiler for reheating.

Water to be heated by the hot water heating cylinder 1 enters the lower chamber 11 through the water inlet 5. The water rises within the lower chamber 11 and passes through the communicating pipe 9 into the upper chamber 10. Water passing through the upper coil portion 13 and the lower coil portion 14 therefore heats the cold water passing through the chambers 10, 11 through heat transfer. The temperature of the water is therefore increased as the water rises through the cylinder 1. Hot water then exits from the upper chamber 10 through the hot water delivery outlet 6. The temperature of the water is monitored by the thermostats 20 and 21.

When water passing through the cylinder 1 reaches a desired temperature as controlled by the thermostats 20 21 passage of hot water from the boiler into the hot water inlet 27 is stopped and the water within the cylinder 1 is simply stored until it is discharged through the outlet 6 as required.

The insulating material 22 ensures that the heat loss from heated water within the cylinder 1 is kept to a minimum.

In use, a small volume of water only may be required to be heated by the cylinder 1. Therefore, a volume of hot water corresponding to the volume of the upper cylinder 10 can be heated simply by allowing hot water to flow through the upper coil portion 13 in the upper chamber 10. The hot water in the upper coil portion 13 can then be returned through the communicating pipe 16 and three-way valve 17 through the outlet 23. The three-way valve 17 is adjusted to facilitate this flow path of the hot water within the coil 2.

The three way valve 17 is suitably a motorised three way valve such as a three way flow diverter valve. In use, when a large volume of water is to be heated as previously described, the three way flow diverter valve 17 is biased such that water cannot flow from the connecting pipe 16 into the valve 17 and out through the boiler outlet 23. Therefore, the heating water follows a path through the hot water inlet pipe 27, the upper coil 13 into the connecting pipe 16 and the side inlet 28, through the lower coil 14, the outlet 29, into the valve 17 and out through the boiler outlet 23. Alternatively, when a small volume of water only is required, the valve 17 is switched to a position in which heating water may not flow through the lower coil outlet 29.Therefore, the heating water follows a route through the hot water inlet 27, the upper coil 13, the connecting pipe 16 into the valve 17 and exits through the boiler outlet 23. Water may enter the lower coil 14 through the side inlet 28 but it cannot exit through the outlet 29 which is closed by the valve 17.

Alternatively, in use, water to be heated follows the same path but is heated in the upper and/or lower chambers 10, 11 by the immersion bases 19, 18 respectively.

The cold water inlet 5 and the hot water outlet pipe 6 are suitably made from a 25 mm bore piping. Likewise, the communicating pipe 9 is suitably made from 25 mm bore piping. The hot water inlet 27 and the heating coil 2 are suitably made from 18 mm bore piping.

The pipes utilized in the water cylinder of the invention can be manufactured from expansion pipes.

The insulating material 22 is preferably a foam insulating material such as a polystryrene material as previously described. The polystyrene material can be sprayed in liquid form onto the side wall 2 and top wall 4 and solidify in-situ. The insulating wall 7 is preferably formed from injected foam polystryrene material to minimise heat transfer between the upper chamber 10 and the lower chamber 11 thereby minimising energy losses from the cylinder 1.

The flow of water in the water cylinder of the invention can be powered by an electric pump which can be located remote from the cylinder e.g. adjacent a fire place backboiler.

Accordingly, the heating water follows the path of least resistance through the connecting pipe 16 and out through the outlet 23.

In an alternative embodiment, the flat top wall 25 and the convex lower wall 26 either side of the insulating wall made up of the insulating material can be omitted so that the upper chamber 10 and the lower chamber 11 are simply separated by insulating material. The insulating material 7 therefore prevents heat conduction between the upper chamber 10 and the lower chamber 11 as previously described but the water cylinder of this embodiment is more integral in nature. The upper chamber 10 and the lower chamber 11 cannot be separated from each other.

Claims

1. A water heating cylinder comprising a fluid tight cylinder, a cold water inlet into the cylinder, a heated water outlet from the cylinder, and heating means for heating water within the cylinder, characterised in that the heating means comprises a heat exchange coil providing two alternative flowpaths through the cylinder, a first flowpath for heating water in the upper part of the cylinder only and a second flowpath for heating water throughout the cylinder, and a valve for directing the heat exchange medium alternatively along one flowpath or the other flowpath.

2. A water heating cylinder comprising a fluid tight cylinder, a cold water inlet into the cylinder, a heated water outlet from the cylinder, heating means for heating water within the cylinder and a control means for controlling water heating characterised in that the cylinder has a first water heating chamber and a second water heating chamber and the heating means is disposed within the first and second water heating chambers, the control means being adjustable such that water from the cold water inlet in the first and second chambers can be heated independently, the heated water being dischargeable through the heated water outlet.

3. A water heating cylinder as claimed in claim 2 characterised in that the first and second water heating chambers are separated by an insulating wall, a communicating pipe being mounted in the wall to facilitate communication between the first and second water heating chambers.

4. A water heating cylinder as claimed in claim 2 or claim 3 characterised in that the heating means comprises a heating coil.

5. A water heating cylinder substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.