Over the years, tap or faucet systems for hand-washing have assumed various different configurations. A basic system includes a pair of taps with associated independent valve mechanisms, with one tap connected to a cold water supply, and the other tap connected to a hot water supply, with each tap having its own outlet. The more commonly used system has a single outlet, with respective hot and cold supplies mixed via separate taps and piped through that single outlet.

Most tap systems utilise hot water storage tanks, which store and heat water, ready for use by prospective users. These storage tanks are generally either located at the point of use or centrally within a building for supplying one or more locations. The most common storage tank is what is generally referred to as a"hot water service". Due to the potential for growth of harmful organisms such as Legionella bacteria, these storage tanks are generally maintained at temperatures greater than 55°C. However, although successful in inhibiting bacteria growth, for the purposes of hand-washing, this temperature is too high. Typically, this heated water is delivered to the point of use where it is then tempered with colder water from the mains supply.

Some hand-washing, or bathroom sink type, tap systems use (unpressurised) storage tanks which are generally termed"open outlet storage tanks". These tanks commonly have their outlets directly connected to a single tap or delivery point and water flow is achieved by feeding more water into the tank which subsequently pushes heated water out through the tap. A problem with open outlet tanks is that they allow water at a hotter storage temperature to flow up the outlet pipe-work by convention while not in use, thus allowing an initial hot and potentially scalding discharge when first operated after a period of non- use. Another problem with tap systems utilising directly connected open water tanks is that expansion and contraction of the system hardware can cause the tap to leak or drip. If water is allowed to remain in the tap/outlet, or in closely connect pipe-work, then corrosion and/or bacteria growth can occur.

It is therefore an object of the present invention to provide an improved liquid dispensing system.

A further object of the present invention is to provide a liquid dispensing system which substantially eliminates dripping associated with its outlet.

With these objects in view the present invention provides a liquid dispensing system including at least one liquid supply means, piping to connect said at least one liquid supply means to an outlet for dispensing liquid from said at least one liquid supply means and an overflow tank connected to said piping between said at least one liquid supply means and said outlet to collect non-dispensed liquid in said piping.

Preferably said overflow tank is located at a point lower than said outlet to allow non- dispensed liquid in said piping upstream of said overflow tank to flow back into said overflow tank. In a preferred embodiment said at least one liquid supply means includes a cold water supply and a hot water supply and said hot water and said cold water are mixed in said piping prior to delivery to said outlet. Preferably said piping includes a T-junction with said outlet, said cold water supply and said hot water supply being coupled to respective ends of said T-junction. Preferably the main arm of said T-junction connects to said overflow tank which is upstream of said cold water supply.

In a practical embodiment said cold water passes through a venturi upstream of said cold water supply but downstream of said overflow tank. The hot water supply may be provided by a storage chamber which includes a heating element that heats water entering said storage chamber from said cold water supply. Preferably the temperature of the hot water in said storage chamber and the temperature of said cold water supply are monitored to provide a relatively constant temperature of water leaving said outlet.

In a further practical embodiment said outlet includes an object sensing means which detects the presence of a hand to allow automatic operation of said liquid dispensing system. Preferably said object sensing means is incorporated in an aerator located in said outlet.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, in which:- Fig. 1 is a cross-sectional view of an operational schematic drawing of a liquid dispensing system made in accordance with a preferred embodiment of the invention; Fig. 2 is a perspective view of the liquid dispensing system shown in Fig. 1 in its protective casing; Fig. 3 is a perspective view of the dispensing system shown in Fig. 2 shown connected to a basin; and Fig. 4 is an enlarged view of the tap shown circled by with reference numeral 4 in Fig. 3.

In the drawings there is shown a liquid dispensing system 10 for the controlled dispensing of hot water, and particularly for hand-washing purposes as shown. It is to be understood that the invention is not intended to be limited to hand-washing applications, and as such could be used in any application which requires a dispensed liquid.

Liquid dispensing system 10 includes a supply valve 12 connected to a cold water supply inlet 14. Supply valve 12 is preferably a solenoid, but may be any other suitable device which can control water flow. On the upstream side of supply valve 12 is a first piping section 16 connecting supply valve 12 to a regulating valve 18. Regulating valve 18 is any suitable device which can control and regulate the flow of water in two upstream directions, as indicated by arrows 20,22. In the direction of arrow 20, regulating valve 18 is shown connected to a second piping section 24 which connects regulating valve 18 to a T-j unction 26. T-junction 26 is connected to a storage tank or reservoir 28 and to a third piping section 30. Piping section 30 subsequently connected to a second T-junction 32 and a water outlet 34, via a fourth piping section 36. Thus a first flow path 38 is defined between the first upstream direction 20 of regulating valve 18 and water outlet 34. In the direction of arrow 22, regulating valve 18 is connected to a fifth piping section 40 and a storage tank 42. Storage tank 42, is a hot-water storage tank, and includes a heating element 44 and temperature sensor 46. Finally, storage tank 42 is connected to water outlet 34 via a sixth piping section 48 to the fourth piping section 36 through second T-junction 32. Thus a second flow path 50 is defined between second upstream direction 22 of regulating valve 18 and water outlet 34.

Storage tank 28 includes two openings 52,54 and a float 56. Opening 52 opens into T-

junction 26, and opening 54 opens into ambient air. Opening 52 of storage tank 28 is positioned such entry to storage tank 28 is at a lower point than water outlet 34 causing undispensed water contained between water outlet 34 and T-junction 26 to flow back into storage tank 28 by convection and/or gravity. Float 56 includes two sealing faces 58,60 which co-operate with two valve seats (not shown) formed on openings 52,54. Sealing face 58 allows opening 54 of storage tank 28 to close when storage tank 28 is filled with water, whereas sealing face 60 allows opening 52 to close when storage tank 28 is emptied. First flow path 38 also includes a venturi 62, positioned on the downstream side of T-junction 32, in close proximity to storage tank 28. The inclusion of venturi 62 is such that water flowing from regulating valve 18, in first upstream direction 20, is forced to pass through venturi 62, lowering the pressure of this water in doing so. It is to be understood to those skilled in the art that venturi 62 is included as a means of emptying any water which may have accumulated in storage tank 28 due to the drop in pressure.

Fig. l also illustrates an object sensing means 64, a cold water temperature sensor 66 and a control circuit 68. Object sensing means 64, which is preferably a pair of infra-red sensors (Fig. 4), shown positioned on water outlet 34. Typically object sensing means 64 detects the presence of a user's hand when their hands are to be washed. Object sensing means 64 includes an aerator 65 and replaces the usual aerator supplied with the tap and can be screwed into place on water outlet 34. In this way no adaptations are needed to an existing tap. Control circuit 68, shown connected to a mains electricity supply 70 and controls operation of system 10. Control circuit 68 receives signals from object sensing means 64 and controls the supply of cold water from supply valve 12. Control circuit 68 may also control heating element 44 of storage tank 42 by monitoring of temperature sensor 46.

Cold water temperature sensor 66 detects any variation in the temperature of cold water supplied to system and control circuit 68 can compensate to maintain a controlled hot water temperature from water outlet 34 all year round which is not effected by variations in supply water using sensors 46,66.

In use, dispensing system 10 is contained within a protective casing 72 below a basin or sink 74. Protective casing 72 will typically be mounted in a cupboard or vanity unit.

When object sensing means 64 detects the presence of a user's hand cold water is supplied to system 10, via cold water supply inlet 14 and supply valve 12. Control circuit 68 allows supply valve 12 to open causing cold water to flow to regulating valve 18 via first piping

section 16. At regulating valve 18, depending on its pre-set adjustment, cold water will flow in directions 20,22. In first path 38, cold water sequentially flows through venturi 62, via second piping section 24, past T-junction 26 along third and fourth piping sections 30, 36, through second T-junction 32, and exits through water outlet 34. Any water contained in storage tank 28 will be emptied along the way. At second flow path 50, the cold water travels along fifth piping section 40, into storage tank 42, which is heated to a predefined temperature controlled by temperature sensors 46,66 and control circuit 68. Hot water will then flow out along sixth piping section 48 to second T-junction 32. At second T-junction 32, cold water travelling down first flow path 38 will mix with hot water from storage tank 42 to provide hot water at water outlet at a temperature which will not scold the user.

After the user has finished washing their hands, they will remove their hands from the proximity of object sensing means 64 and control circuit 68 will stop water flow at supply valve 12. At this point, any water remaining in water outlet 34 will either flow out of water outlet 34, or be returned to fill storage tank 28 along fourth and third piping sections 36,30 respectively by convection and/or gravity action. Accordingly, this action will substantially eliminate any chance of water outlet 34 dripping or leaking. Any water which reaches second T-junction 32 from the sixth piping section 48 and storage tank 42, for example due to fluctuations in temperature of contained fluid which may cause expansion and contraction of associated piping section 48, will also flow back toward storage tank 28.

It should be understood by those skilled in the art that the inclusion of storage tank 42 and related hardware is not essential. For example, storage tank 42 may be replaced by an existing hot-water service or other heated water supply. In fact, in the above described embodiment, second flow path 50 and regulating valve 18 can be removed completely, so long as hot water is supplied to water outlet 34 via sixth piping section 48 and T-junction 32. In an alternate embodiment (not shown) hot water could be supplied at the sixth piping section 48, which may include a solenoid of its own, when control circuit 68 responds to object sensing means 64. It is also to be understood that float 54 of storage tank 28 is not essential. In fact, storage tank 28, in its simplest form may be a reservoir, so long as it can contain the non-dispensed water left in piping sections 30,36 and 48.

The present invention therefore provides a useful solution to the problems previously discussed in relation to water level fluctuations due to expansion and contraction of associated

hardware with a tap or faucet system, and the potential of scalding due to hot water remaining in an outlet. A simple answer to the problems results which provides a apparatus for dispensing fluid which includes a storage tank for containing non-dispensed water remaining in associated pipe-work and expansion water due to heat fluctuations. This storage tank simply allows non-dispensed water to flow back into it by convention/gravity, thus substantially eliminating water from internal pipe-work in close proximity to an associated outlet. The present invention therefore provides an improved liquid dispensing apparatus which does not drip and has improved temperature regulation properties.

Throughout this specification, unless the context requires otherwise, the word"comprise", or variations such as"comprises"or"comprising", will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

The invention will be understood to embrace many further modifications as will be readily apparent to persons skilled in the art and which will be deemed to reside within the broad scope and ambit of the invention, there having been set forth herein only the broad nature of the invention and a certain specific embodiment by way of example.