GB2280493A

GB2280493A - Hot water supply unit and water container therefor

Info

Publication number: GB2280493A
Application number: GB9413961A
Authority: GB
Inventors: David Nichols; Derrick Purser
Original assignee: NOVOMEC Ltd
Current assignee: NOVOMEC Ltd
Priority date: 1993-07-14
Filing date: 1994-07-11
Publication date: 1995-02-01
Anticipated expiration: 2014-07-11
Also published as: GB9413961D0; GB2280493B; GB9314558D0

Abstract

A hot water supply unit which has a moulded plastics water container (14) which, when the unit is mounted for use, has a length of approximately twice its depth, and is integrally formed with necks (16, 18, 32) for the connection of inlet and outlet pipes (20, 22) leading to a mixer means and for the connection of an S-shaped heating element (40) extending horizontally below a horizontal temperature sensor (36). Opening the valve 26 allows cold water to enter the container (14) from inlet (24). Hot water is then displaced from the container through mixing valve (28) to outlet (30). The container may be a blow moulding or may comprise a rotationally moulded body to which moulded end caps are sealed. <IMAGE>

Description

Hot Water Supply Unit and Water Container Therefor This invention relates to a hot water supply unit and water container therefor.

It is an object of the invention to provide a point-of-use water heater which is economical and simple to operate, and easily installed more particularly above or below a sink or basin. It is a further object of the invention to provide an inexpensively produced water storage container for use in the water heater.

According to the invention, there is provided a hot water supply unit comprising a water storage container which when mounted for use has a greater horizontal dimension than vertical depth, an entry for cold water leading to the bottom zone of the container, an exit for hot water from the top zone of the container, a connection at which an electric heating element is mounted to extend at least partially across the container in the bottom zone thereof, and a connection for mounting of a temperature sensitive element which in use senses the temperature of the water in a median zone of the container above the heating element.

A preferred form of the unit is of the open outlet type operating on the displacement principle, i.e. opening of an inlet control valve, e.g. a tap through which cold water enters the container through the cold water inlet, causes displacement of hot water from the container through the hot water outlet.

The hot water outlet preferably leads to a mixer valve, e.g. a mixer tap, at which cold water from the seme inlet supply is mixed to a chosen extent with the hot water emergent from the storage container. Thus, delivery of water is controlled at the cold water inlet; the mixer valve only controls the amount of cold water mixed with the exiting hot water.

The design of the water storage container, and in particular its substantial horizontal dimension compared with its vertical depth, is important in efficient realisation of the above-described hot water delivery system. Turbulence of the water within the container is minimised, so that the temperature gradient of the water in the container is kept substantially stable from top to bottom.

According to a further feature of the invention, there is provided a water storage container for water for a hot water supply unit, comprising a plastics container having a generally cylindrical shape with two spaced integral necks in its cylindrical wall for connection of inlet/ outlet pipes, one closed end and an integral neck at the other end for connection of an electric heating means.

The plastics container may be produced by blow moulding, or the cylindrical part may be produced by rotational moulding and the container closed by application of moulded end caps, one having a neck, sealed to the cylindrical part.

In the hot water supply unit of the invention, this moulded plastics water storage cylinder is mounted with its axis generally horizontal. The two integral necks for water inlet and outlet can be positioned either at the bottom for oversink installation of the unit or at the top for undersink installation. In the case of oversink installation, a cold water inlet pipe will extend upwardly through one of the necks into the bottom zone of the water storage container whilst a relatively longer hot water outlet pipe will extend upwardly through the other neck and through the container into the top zone thereof. In the case of undersink installation, the cold water inlet and hot water outlet pipes will extend downwardly, the cold water inlet pipe being the relatively longer pipe.

The integral neck at one end of the water storage container is preferably an on-axis neck and receives a generally Sshaped heating element which inside the container has an intermediate portion extending downwardly and a terminal portion extending parallel to the container axis in the bottom zone of the container. The same water storage container and heating element can thus be used for both oversink and undersink installation.

The integral neck at the one end of the water storage container is conveniently also employed for connection of a sensing phial which in use serves for water temperature control by adjustment of an external control knob as well as a safety cut-out if, for example, the heat is switched on while the storage container is empty of water. The sensing phial is preferably substantially straight, extending parallel to the container axis in a median zone of the container so as to cross the downwardly extending portion of the heating element, where an interconnection is effected to ensure a reliable and prompt safety cut-out.

The moulded plastics water storage container is preferably encased in thermal insulating material, e.g. glass fibre filled quilted lagging, within an external casing, e.g.

of anti-corrosion ABS, which casing in addition to the thermostat control knob is equipped with an electrical supply on/off neon indicator and a heat on/off neon indicator.

Further features of the hot water supply unit and water storage container in accordance with the invention will be apparent from the following description of a practical embodiment, making reference to the accompanying drawing, the single figure of which is a diagrammatic side elevational view of an oversink installation.

Referring to the drawing, the illustrated hot water supply unit, mounted above a basin or sink, comprises an external casing 10 of anti-corrosion ABS accommodating a water storage container 12 which is of blow moulded construction.

The container 12 is encased in glass fibre filled quilted lagging 14 with a barrier membrane.

The container 12 can alternatively be made. as a cylindrical part formed by rotational moulding to which moulded end caps are sealed.

The water storage container 12 is a moulded cylinder of greater length than diameter (in a ratio of about 2:1), and it is important to note that in use it is orientated with its axis horizontal. Two spaced integral necks 16, 18 in the cylindrical side wall of the container provide for sealed entry of a cold water inlet pipe 20 and a hot water outlet pipe 22, respectively. In the case of the oversink installation illustrated, the cold water inlet pipe 20 extends upwardly to open into the bottom zone of the container and the hot water outlet pipe 22 extends upwardly to receive hot water into its open end in the top zone of the container.

Below the casing of the hot water supply unit the pipes 20, 22 connect to a manifold arrangement which comprises a mains cold water inlet 24 (direct from the mains supply or a tank providing an adequate pressure head), a cold water inlet control valve 26 (on/off tap), a mixer control valve 28 (water temperature control tap) and a water delivery spout 30.

The unit operates on the water displacement principle.

When the tap 26 is opened, the cold water entering the bottom zone of the container displaces hot water out of the top zone of the container. This hot water is mixed to a chosen extent with cold water at the mixer tap 28.

This means of water delivery control is enabled by the unusual arrangement and orientation of the water storage container 12, wherein water turbulence is minimised and a stable temperature gradient of the water from top to bottom is maintained within the container.

The above-described means of water delivery is but one example of a number of available options.

The container 12 (or one end cap thereof) is also moulded with an on-axis integral neck 32 at one end, used for sealed insertion of an S-shaped heating element 34 and a sensing phial 36. The heating element 34 extends downwardly within the container at 38, and has a main terminal portion 40 extending parallel to the container axis in the bottom zone of the container. The sensing phial is substantially straight and extends across a median zone of the container above the portion 40 of the heating element. It thus intersects the downwardly extending portion 38 of the heating element and, at this point, an interconnection is made to provide a safety cut-out in the event of the heater being switched on when the container is empty of water. The heating element is preferably of the embedded rod type, alloy sheathed for aggressive water conditions.

The sensing phial 36 also incorporates a thermostat for water temperature control, adjustable by a control knob 42 on the external casing 10.

This external casing is also provided with a mains supply on/off neon indicator 44 and a heating current on/off neon indicator 46. The electric supply cable to the unit is referenced 48.

A preferred unit may have a water storage capacity of 5 or 10 litres, and heat water to a temperature 85 degrees C, with a range of settings down to 35 degrees C for anti-frost protection.

An undersink installation is generally similar, but the orientation of the container in the vertical direction is reversed. The cold water inlet extends through the one integral neck at the top of the container and down to the bottom zone, whilst the shorter hot water inlet extends upwardly through the other integral neck from the top zone of the container. Moreover, these pipes may connect to a tap manifold conventionally mounted on the sink.

Claims

1. A hot water supply unit comprising a water storage container which when mounted for use has a greater horizontal dimension than vertical depth, an entry for cold water leading to the bottom zone of the container, an exit for hot water from the top zone of the container, a connection at which an electric heating element is mounted to extend at least partially across the container in the bottom zone thereof, and a connection for mounting of a temperature sensitive element which in use senses the temperature of the water in a median zone of the container above the heating element.

2. A unit according to claim 1, of the open outlet type operating on the displacement principle, wherein opening of an inlet control valve, through which cold water enters the container through the cold water inlet, causes displacement of hot water from the container through the hot water outlet.

3. A unit according to claim 2, wherein the hot water outlet leads to a mixer valve, at which cold water from the same inlet supply is mixed to a chosen extent with the hot water emergent from the storage container.

4. A unit according to any of claims 1 to 3, comprising a plastics container produced by moulding and having a generally cylindrical shape with two spaced integral necks in its cylindrical wall for connection of inlet/outlet pipes, one closed end and an integral neck at the other end for connection of an electric heating means.

5. A unit according to any of claims 1 to a, wherein, in the case of oversink installation, with the inlet and outlet necks positioned at the bottom, a cold water inlet pipe extends upwardly through one of the necks into the bottom zone of the water storage container whilst a relatively longer hot water outlet pipe extends upwardly through the other neck and through the container into the top zone thereof.

6. A unit according to any of claims 1 to 4, wherein, with the inlet and outlet necks positioned at the top, in the case of undersink installation, cold water inlet and hot water outlet pipes extend downwardly, the cold water inlet pipe being the relatively longer pipe.

7. A unit according to any of claims 1 to 6, wherein the integral neck at one end of the water storage container is an on-axis neck and receives a generally Sshaped heating element which inside the container has an intermediate portion extending downwardly and a terminal portion extending parallel to the container axis in the bottom zone of the container.

8. A unit according to claim 7, wherein the integral neck at the one end of the water storage container is also employed for connection of a sensing phial which in use serves for water temperature control by adjustment of an external control knob as well as a safety cut-out.

9. A unit according to claim 8, wherein the sensing phial is substantially straight, extending parallel to the container axis in a median zone of the container so as to cross the downwardly extending portion of the heating element, where an interconnection is effected to ensure a reliable and prompt safety cut-out.

10. A unit according to any of claims 1 to 9, wherein the moulded plastics water storage container is encased in thermal insulating material within an external casing.

11. A unit according to claim 10, wherein the external casing carries a thermostat control knob, a supply on/off neon indicator and a heat on/off neon indicator.

12. A hot water supply unit substantially as hereinbefore described with reference to the accompanying drawings.