GB2245959A - Multi-purpose water heater - Google Patents

Abstract

A multi-purpose water heating installation includes a water heating cylinder 1, divided into a lower compartment 2 for supplying a main mass of heated water and an upper compartment 3 for supplying smaller volumes of water for instant use. Cold water supplied to the base of the cylinder from a cistern 5, is heated by immersions 6 and may be drawn off from outlet pipe 7. The compartments are connected by a riser 8 and the water in the upper compartment is heated by immersions 9. A further cold water branch 11 from the cistern 5 feeds a preheat coil 12 connected in series with a coil 13 wherein the water is heated to the required temperature for instant use. The water in the coil 13 may be drawn off from outlet 14. In an alternative embodiment, figure 2 not shown, for providing additional water for a central heating system, an additional coil 32, connected to the central heating system, is provided in the lower compartment. To provide supplementary heat for the central heating system, the upper and lower compartments are isolated from one another and a pipe 41 leads from the return from the heating system to the upper compartment and a pipe 42 leads from the upper compartment to a pump 44 and a diverter valve 39. <IMAGE>

Description

Multi-Purpose Water Heating Installation This invention relates to a multi-purpose water heating installation, intended to provide heated water for several different domestic requirements, from a single installation.

At present, water heating installations are adapted to and optimised for the provision of heated water supplies for only one or two functions- such as the rapid heating of small volumes of water for instant use, as for showers or washingup on the one hand, or the bulk heating of large volumes of water over a longer period of time, usually to a somewhat lower temparature, for uses requiring larger volumes such as bathing or laundry on the other, or the provision of a constant heat bank for use in water radiator space heating.

Because of this element of specialisation, it has been usual either to provide a separate heater for each different purpose, or to provide a heater which makes an acceptable compromise in the provision of either instant availability of hot water in small quantities, and the longer term provision of a body of heated water for larger uses, with one or both requirements met with some sacrifice of efficiency.

A further requirement for space heating is more difficult from the same installation, as water for heating radiators usually has corrosion inhibitors and other additives which require that it is kept separate from water used for washing and drinking, and must consequently be kept in a separate circuit.

An object of this invention is to provide a multipurpose water heating installation which is capable of meeting two or more different requirements simultaneously, for example for both rapid provision of a limited quantity of hot water, and of a larger volume of heated water. Preferrably the installation may also be capable of providing water for central heating, and performing all these functions with equal efficiency.

According to the invention, a multi-purpose water heating installation comprises a water heater cylinder divided into a larger lower main compartment for providing a large volume of heated water, a smaller upper compartment, and a heat transfer coil in each compartment, the coils being connected in series for circulation of a volume of water through both compartments of the cylinder for heat exchange with the water in the compartments.

The lower compartment may have a cold water inlet at the bottom and a heated water draw off connection near the top, and an overflow arrangement to allow water tb enter the upper compartment from the lower under hydrostatic pressure, and the upper compartment may also have an expansion outlet at the top.

Heating of the water in each compartment may be effected by electrical immersion heaters, a plurality of which may be provided for the upper compartment for rapid heating of the water therein, and thence that passing through the coil, on demand.

The water from the lower compartment may be used for bulk requirements such as laundry or bathing, and the water circulated through the coil used for immediate demands for smaller quantities of hot water for uses such as showers or washing-up.

A further heat exchange coil may be provided in the lower compartment for circulating a separate water supply, for example for central heating, through the bank represented by the body of water in the lower compartment, and the central heating circuit may also include a parallel connection to the body of water in the upper compartment, which in this case is isolated from the other water circuits, to keep central heating water, which may be doped with additives, separate from water for other uses.

Two embodiments of water heating installation according to the invention will now be described by way of example, with reference to the accompanying drawings, wherein: Fig. I is a diagram of a first embodiment of water heating installation according to the invention; Fig. 2 is a similar diagram of a second embodiment of water heating installation according to the invention; and Fig. 3 is a sectional view of an upper compartment of a water heating cylinder forming part of either embodiment, showing the dispositions of electrical immersion heaters therein.

As shown in Fig. 1, a first embodiment of water heating installation according to the invention includes a water heating cylinder 1, divided into a lower compartment 2 and an upper compartment 3. Cold water is supplied to the base of the compartment 2 by a pipe 4 from a reservoir cistern 5, and heated therein by thermostatically controlled electrical immersion heaters 6, one near the bottom and one near the top of the compartment 2. The water fills the compartment 2 due to hydrostatic pressure or 'head' from the reservoir 5, and may be drawn off when required by use of an outlet pipe 7 at the top of the compartment. The water will rise further under the pressure head via a riser pipe 8 into the smaller upper compartment 3, filling this in turn. A plurality, e.g. two (see Fig. 3) electrical immersion heaters extend parallely into the compartment 3.An expansion pipe 10 is taken off from the apex of the compartment 3, perhaps via an expansion tank, or a trap loop (shown), and this serves as an overflow return to the cistern 5.

A further cold water feed branch 11 from the cistern 5 feeds a heat exchange coil 12 in the lower compartment 2, which is connected in series with a further coil 13 in the upper compartment 3, and leads via an outlet pipe 14 to user appliances such as hot-water taps, showers, etc.

The lower compartment 2 heats a main mass of water using the immersion heaters 6, to a selected temparature suit suitable for bulk use in bathing, laundry etc. and the temparature maintained by the heaters always being ' on subject to thermostatic control. This also provides a heat storage bank with a considerable thermal inertia, which can heat up water from pipe 11, preheating it, and the water in the upper compartment, so that the heaters 9 in the upper compartment, switched on on demand with a thermostatic cut off point, have relatively little work to do in further heating the water for demand use.

In Fig. 2, a second embodiment has an additional coil for use in providing a central heating supply. A water heating cylinder 21 is divided into a lower larger compartment 22 and a smaller upper compartment 23. Cold water is admitted through pipe 24 to the bottom of compartment 22 froma cistern 25, and heated by electrical immersion heaters 26, one near the bottom, and the other near the top of the compartment 22. The heated water can be drawn off for use from the top of the compartment 22 through an outlet pipe 27. The upper compartment 23 is isolated from the lower compartment 22 so that there is no communication between the water volumes.

A futher cold water feed 31 is connected to a heat exchange coil 32 in the lower compartment 22, and this coil 32 is connected in series with a second heat exchange coil 33 in the upper compartment 23, leading to an outlet pipe 34 for supply of heated water circulated through the coils 32, 33 to hot water taps etc.

A further heat exchange coil 35 is located in the lower compartment 22, with an inlet 36 and an outlet 37.

Inlet 36 admits cooled water from a heating load 38, such as a series of radiators or the like, forming a central heating system. The outlet 37 is connected by a diverter valve 39 to the heating load 38. The oulet from the pipe to valve 39 is also connected by a circulating pump 44 to the space 23.

Water is circulated to space 23 by inlet 41 by a branch from the connection of the heating load to the further coil inlet 36, so that coil 33 transfers heat from space 22 to space 23 to reheat a proprtion of the water from the heating load 38.

An expansion pipe 30 leaves from the apex of the compartment 23 and may communicate with an expansion tank or air vents, and forms a return to the cistern 25.

Fig. 3 is a sectional view from above of the upper compartment 2 or 23, showing two immersion heaters 9 or 29 arranged to extend parallely inwards through an insulating jacket 45.

The first embodiment of installation is equally efficient at providing bulk heated water, and smaller volumes of hotter water on demand. The second embodiment combines this with the efficient provision of a heat bank which maintains the temparature of a body of central heating water.

It will be noted that the central heating water is isolated from water for other uses, as anti-corrosion and other additives must be kept out of potable and washing water, but are usually used -in central heating water.

Claims (2)

CIAIMS:-

1. . - A multi-purpose water heating installation comprises a water heater cylinder divided into a larger lower main compartment for providing a large volume of heated water, a smaller upper compartment, and a heat transfer coil in each compartment, the coils being connected in series for circuiation of a volume of water through both compartments of the cylinder for heat -exchange with the water in the compartments.

2.A water heating installation as described herein and exemplified with reference to the drawings.