WATER INTERFACE UNIT FOR INTERFACING A SUPPLEMENTARY WATER SUPPLY, EG RAINWATER, WITH A MAINS WATER SUPPLY

Field of the invention

The invention relates to a water interface unit and to components therefor.

Background of the invention Water interface units are used for communicating two water sources, such as a mains water supply and a rainwater tank, with a common outlet. Known interface units operate to supply rainwater from the rainwater tank when available and then switch to mains water when the rainwater tank is empty. This advantageously allows a rainwater tank to be used, thus decreasing demands on the mains water system and conserving water, without inconvenience to the user.

Some water interface units found on the market co-operate with an associated pump to pressurise water from a rain water tank. These water interface units employ a sensor associated with the common outlet to provide a signal indicative of consumer demand, and are configured to activate the associated pump in response to said indicative signal. Some interface units employ a pressure sensor associated with the common outlet for this purpose and are configured to activate the associated pump in response to the detected pressure falling below a predetermined threshold. Other water interface units employ a flow sensor, or flow switch, and are configured to activate the pump when flow above a predetermined threshold is detected.

These water interface units have a number of drawbacks. Small "consumer demands" for water, such as a small leak in the plumbing, can result in the intermittent activation of the pump which can quickly burn out the pump motor. The delivery of low to moderate flow rates involves significant downstream throttling. The pump has to work against this throttling. This is, of course, inefficient.

Some water interface units co-operate with the an associated float sensor in the rain water tank. The float sensor provides an indication of the volume of water in the rain

water tank and the interface unit is configured to only take rain water from the rain water tank when there is a sufficient volume of water in the tank.

Float sensors can fail so as to provide a false indication of water in the rain water tank. Such a failure can result in the pump running dry. This can damage the motor of the pump.

Water interface units found in the market include a number of off-the-shelf components assembled which are generally assembled on site or within a common housing. The components are typically connected using threaded joints. The components required to complete such joints are relatively expensive, as is the associated labour. The joints between components are relatively weak points where leakage is prone to occur. These known constructions are also often bulky, unsightly and prone to damage.

Objects of the present invention include to provide an improved interface unit and components therefor, or at least provide alternatives in the marketplace.

Summary of the invention In one aspect of the invention there is provided a plumbing fitting for interfacing a supplementary water supply and a mains water supply with a point of consumer demand, the plumbing fitting being integrally formed and comprising:

a mains water inlet for receiving water from a mains supply,

a supplementary water inlet for receiving water from a supplementary water supply,

an outlet for supplying water to the point of consumer demand,

valve mounting means for mounting a valve means to selectively communicate the mains water inlet with the outlet, and

at least one sensor mounting aperture, optionally proximal to the outlet, for mounting a sensor to provide an indication of at least one flow parameter of water at the outlet.

Preferably a conduit uninterrupted by controllable valve means communicates the supplementary water inlet with the outlet.

Advantageously the valve mounting means may include a trough surrounding a central aperture and be adapted to cooperate with a valve for selectively communicating the trough and the central aperture. Preferably the trough is arranged to fluidly communicate with the mains water inlet and the central aperture is arranged to communicate with the outlet. The central aperture may be aligned with the supplementary water inlet. Preferably a mains conduit extending from the mains water inlet is parallel to, and most preferably coaxial with, an outlet conduit extending from the outlet. Advantageously a supplementary conduit extending from the supplementary inlet is arranged perpendicular to the outlet conduit.

The flow parameter may be one or more properties such as pressure or flow rate. Preferably an aperture for mounting a pressure sensor and an aperture for mounting a flow sensor are provided.

Preferably the sensor mounting apertures and the valve mounting means are substantially parallel for coring from a common direction.

The plumbing fitting is preferably predominantly formed of a synthetic thermoplastic or thermosetting material. Advantageously, threaded inserts may be encapsulated within one or more of the mains water inlet, supplementary water inlet, the outlet and the sensor mounting aperture(s).

In another aspect of the invention there is provided a housing for a water interface unit, the housing containing a plumbing fitting integrally formed with at least a portion of the housing, the plumbing fitting including:

a mains water inlet for receiving water from a mains water supply,

a supplementary water inlet for receiving water from a supplementary water supply, and

an outlet for supplying water to a household.

Preferably the housing includes a plumbing fitting as previously described. Most preferably the housing is sized to accommodate a valve fitted to the value mounting means, sensors fitted to the sensor mounting apertures and includes means for mounting electrical control means.

Preferably the first housing portion includes an at least approximately planar base portion and the conduits are at least approximately parallel to the base portion. The first housing portion may include wall portions depending from the base portion. Preferably the mains water inlet, the supplementary water inlet and the outlet are each arranged for respectively communicating with a mains water supply, a supplementary water supply and a point of consumer demand via a respective aperture within a respective wall.

In another aspect of the invention there is provided an interface unit including an aforedescribed plumbing fitting or an aforedescribed housing, and valve means, sensors and control means. Preferably the sensors include a pressure sensor and a flow sensor.

In another aspect of the invention there is provided a method of producing a housing for an interface unit, the method includes the step of integrally moulding an aforedescribed housing.

The method preferably includes relatively moving a lower tool and a first upper tool in a first direction to a closed position, and relatively moving a second upper tool in a direction transverse, and preferably perpendicular, to the first direction to the closed position,

the lower tool in the closed position defining a lower surface of the base portion of the housing,

the first upper tool in the closed position defining a portion of the outer surface of the mains water conduit, the supplementary water conduit and the outlet conduit,

the second upper tool in the closed position defining a portion of the outer surface of two of the mains water conduit, the supplementary water conduit and the outlet conduit;

filling a cavity defined by the lower tool, the first upper tool and the second upper tool in the closed position with a flowable material;

allowing the flowable material to set;

relatively moving the lower tool, the first upper tool and the second upper tool to an open position; and

removing the housing.

Preferably the second upper tool at least partly defines the valve mounting means, and the most preferably also the sensor mounting aperture(s). Each tool could be based on a solid billet of material. Each tool may have fixed inserts, for example the second upper tool may have removable inserts to define the valve mounting means and sensor mounting apertures which would allow for a common tool to be used to define a housing adapted for use with different valves and/or different sensors. Of course each tool may include ejector pins and water galleries etc.

In another aspect of the invention there is provided a water interface unit for interfacing a supplementary water supply and a mains water supply with a point of consumer demand, the interface unit including:

a mains water inlet for receiving water from a mains supply;

a supplementary water inlet for receiving water from a supplementary water supply;

an outlet for supplying water to the point of consumer demand;

a first conduit communicating the mains water inlet and the outlet;

a second conduit communicating the supplementary water inlet and the outlet;

control means for controlling a pump, which when activated drives water from the supplementary water supply to the supplementary water inlet;

a flow sensor for providing a signal indicative of a rate of water flow through the outlet;

wherein the control means is configured to vary, in response the signal indicative of the rate of water flow through the outlet, a speed of the pump when the pump is so activated.

The control means may be configured to deactivate the pump in response to the rate of flow through the outlet falling below a predetermined threshold.

Preferably the water interface unit further includes a controllable valve for selectively closing the first conduit; and the control means is configured to open said controllable valve to expose the outlet to mains water pressure when the pump is inactive. The valve is preferably a solenoid valve, and most preferably has a speed of operation selected to avoid water hammer. Said second conduit preferably includes a non-return valve to prevent water flow towards the supplementary water supply.

Optionally, the water interface unit may also include a pressure sensor for providing a signal indicative of water pressure at the outlet. The control means may be configured to activate the pump in response to the signal indicative of the water pressure at the outlet falling below a predetermined threshold. Said pump activation may be conditional on a signal indicative of a predetermined volume of water available from the supplementary water supply; e.g. a float sensor in a rainwater tank.

The control means may be configured to identify a pump active, high pressure, low flow condition and deactivate the pump.

The control means may vary the speed of the activated pump in response to the signal indicative of water pressure at the outlet.

The control means may be configured to drive the pump at a number of discrete speed settings. For example, there might be two speed settings. The control means may include a TRIAC.

In another aspect of the invention there is provided a water interface unit for interfacing a supplementary water supply and a mains water supply with a point of consumer demand, the interface unit including:

a mains water inlet for receiving water from a mains supply;

a supplementary water inlet for receiving water from a supplementary water supply;

an outlet for supplying water to the point of consumer demand;

a first conduit communicating the mains water inlet and the outlet;

a first valve operable to close the first conduit;

a second conduit communicating the supplementary water inlet and the outlet;

a second valve operable to close the second conduit;

control means for controlling a pump, which when activated drives water from the supplementary water supply to the supplementary water inlet;

a flow sensor for providing a signal indicative of a rate of water flow through the outlet;

a pressure sensor for providing a signal indicative of water pressure at the outlet;

wherein said valves and said control means are configured to expose the outlet to mains water pressure when the pump is inactive; and the control means is configured to receive said signals and identify a pump active, high pressure, low flow condition and deactivate the pump.

The first valve is preferably a controllable valve; e.g. a solenoid valve. The second valve is preferably a non-return valve.

Brief description of the drawings

Figure 1 is a perspective view of a housing portion according to an embodiment of the invention;

Figure 2 is a rear perspective view of the housing portion of Figure 1 ;

Figure 3 is a perspective view of a lid cooperable with the housing portion of Figure 1 ;

Figure 4 is a front view of the housing portion of Figure 1 ;

Figure 5 is a side view of the housing portion of Figure 1 ;

Figure 6 is a top view of the housing portion of Figure 1 ;

Figure 7 is a side view of the housing portion of Figure 1 ;

Figure 8 is a bottom view of the housing portion of Figure 1 ;

Figure 9 is a rear view of the housing portion of Figure 1 ;

Figure 10 is a top view of the lid of Figure 3;

Figure 11a is a schematic illustration of a pressure sensor;

Figure 11 b is a schematic illustration of a flow sensor;

Figure 11 c is a schematic illustration of a solenoid valve;

Figure 11d is a schematic illustration of a printed circuit board;

Figure 12 is a schematic exploded bottom view of the housing portion of Figure 1 and additional components;

Figure 13 is a schematic bottom view of an interface unit including the housing portion of Figure 1 and the lid of Figure 3;

Figure 14 is a side view of the interface unit of Figure 13; and

Figure 15 is a rear view of the interface unit of Figure 13.

Detailed description of the embodiments

The interface unit 10 includes a housing portion 80 which is integrally moulded with the plumbing fitting 90. The plumbing fitting 90 includes a mains water inlet 20, a supplementary water inlet 30 and an outlet 40. The interface unit 10 functions to selectively communicate one of a mains water supply or supplementary water supply with a consumer. Conveniently the interface unit 10 can be connected at the water supply line to a household, to the mains water supply and to a supplementary water supply such as a rainwater tank. The interface unit 10 allows the consumer to use supplementary water, e.g. rainwater, when it is available and to otherwise use mains water. The interface unit 10 allows the switch between supplementary water and mains water to happen automatically without inconvenience to the consumer.

As is best illustrated in Figure 13, a permanently open supplementary water path 130 communicates the supplementary water inlet 30 with the outlet 40. A non-return valve 110 is mounted within the inlet 30. The mains water path communicates the mains water inlet 20 with an annular trough 5OC. A solenoid valve 50 is arranged to selectively communicate the trough 5OC with a central aperture 5OB. The central aperture 5OB is in

turn in fluid communication with the outlet 40 via the supplementary water path 30. Thus by opening solenoid valve 50 the supplementary water path 130 is exposed to mains water pressure.

Flow sensor 60 and pressure sensor 70 are mounted within flow sensor aperture 6OA and pressure sensor aperture 7OA and communicate with the supplementary water path 130 proximal the outlet 40 to provide an indication of the water pressure and flow rate at the outlet 40.

A control means in the form of printed circuit board (PCB) 120 is mounted within the interface unit 10. The PCB 120 is operative to control the solenoid valve 50 in response to the flow sensor 60 and the pressure sensor 70. The PCB 120 also controls a pump (not shown) operative to supply pressurised water to the supplementary water inlet, for example a submersible pump mounted within a rain water tank.

The solenoid valve 50 is configured so that the mains water pressure urges the valve closed. The valve incorporates a spring (not shown) to overcome the force of the water pressure and hold the valve open when the pump is inactive. When the pump is active the solenoid is energised to drive the valve closed.

In use when there is no demand from the consumer the pump (not shown) is inactive and the solenoid valve 50 is open. The supplementary water path 130 is thus exposed to mains pressure which in turn closes the non-return valve 110. Demand from a consumer, for example turning on a tap, results in a drop in pressure in the supplementary water path 130 and is thus detected by pressure sensor 70. In response to the pressure sensor 70 the PCB 120 is operative to activate the pump (not shown) and close solenoid valve 50 thus effectively switching from mains water supply to supplementary water supply. Cessation of consumer demand is detected by the combination of a pressure signal above a predetermined threshold from pressure sensor 70 and/or a flow signal below a predetermined threshold from the flow sensor 60. In response to these signals the PCB 120 is responsive to deactivate the pump (not shown) and open the solenoid valve 50 to return the interface unit 10 to the inactive condition.

The PCB 120 is configured to control the pump speed in response to the flow sensor 60. PCB 120 includes a TRIAC for varying the pump speed. In this embodiment, the TRIAC has two speeds - high and low (and of course the TRIAC also has an 'off position). In response to a moderate flow signal the PCB 120 is operative to reduce the pump to the low speed setting so that the pump is not unnecessarily overworked. This embodiment is cooperable with a pump including a four pole induction motor.

A shortage of supplementary water, eg. the emptying of a rainwater tank, during the supply of water to a consumer is detected by a low flow signal from the flow sensor 60. In response to these signals the PCB 120 is operative to deactivate the pump and open the solenoid valve 50 thus returning the consumer to regular mains water supply without inconvenience.

Alternatively, the PCB may be configured to receive a signal for a water detector associated with the rain water tank and only activate the pump when there is sufficient water. Some embodiments advantageously incorporate both means for detecting a shortage of water, thereby providing a degree of redundancy and reducing the risk of the pump running dry.

According to the embodiment of figure 1 the interface unit 10 includes the housing 80 which includes an integrally formed plumbing fitting 90 which is best illustrated in Figure 1. The plumbing fitting 90 includes the mains conduit 2OA, the supplementary conduit 3OA and the outlet conduit 2OA. The mains conduit 2OA and the outlet conduit 40A are coaxially aligned and the supplementary conduit 3OA is perpendicularly connected thereto at a mid point to define a planar T piece.

The housing portion 80 includes a substantially planer base portion 150. The three branches of the plumbing fitting 90 lie in a common central plane. The central plane is parallel to the base portion 150. A valve mount 5OA including the central aperture 5OB, the annular trough 5OC and the screw holes 5OD is provided for mounting the solenoid 50. The valve mount 5OA, the flow sensor aperture 6OA and the pressure sensor aperture 7OA are arranged along the forward extent of plumbing fitting 90 and are

substantially parallel for coring from a common direction as is described in more detail below.

Wall portions 170, 180, 190 project upwardly from the base portion 150 to define an internal region housing the plumbing fitting 90. Bosses 160 extend internally from the base portion 150 for mounting the PCB 120. The mains water inlet 20, the supplementary water inlet 30 and the outlet 40 open through apertures within the walls 170, 180 and 190 respectively.

The housing portion 80 includes recesses 230 and 240 defined along the wall 180. The recess 230 houses an aperture 230A. The aperture 230A in use sealingly accommodates a power supply lead (for supplying power to the PCB 120) with the aid of a sealing gland (not shown). The recess 240 houses aperture 240A which houses a power supply socket for supplying power to the pump (not shown).

The outer surface 200 of the base portion 150 is provided with rib work which underlies the plumbing fitting 90. The rib work serves to hide shrink marks resulting from the physical bulk of the plumbing fitting 90 relative to the otherwise thin walled base portion 150. The rib work also serves to strengthen the base portion 150.

A lid 100 illustrated in Figure 3 is shaped to cooperate to close the housing portion 80 and thereby contain the plumbing fitting 90. As illustrated in Figures 13, 14 and 15 the housing defined by housing portion 80 and the lid 100 is a neat and robust package wherein the internal components are safely shielded from accidental damage and the ingress of detritus.

According to the illustrated embodiment the housing portion 80 including the plumbing fitting 90 is integrally moulded from a synthetic resin material commonly used in producing plumbing fittings. Housing 80 is formed in an injection moulding tool having multiple sliding cores. A lower tool forms the outer surface 200 of the base portion 150. A first upper tool defines the region 210 and includes channels to define the outer surface of the supplementary conduit 3OA (that is 'outer' as in external to the conduit but internal to the housing 80, 100) and a portion of the outer surfaces of main conduit 2OA

and outlet conduit 40A. The first upper tool also defines the portions of recesses 230 and 240 internal to the housing 80, 100.

A second upper tool moves in a fore-aft direction relative to the other tool portions to define the region 220 including internal surfaces of a portion of the base portion 150 and a portion of the wall portions 170 and 190. The second upper tool portion also defines the forward surface of the plumbing fitting 90 including the valve mount 5OA, the flow sensor aperture 6OA and the pressure sensor aperture 7OA.

Pins (not shown) movable relative to the lower tool and upper tools project inwardly to define the mains water inlet 20 supplementary water inlet 30 and the outlet 40.

A third upper tool relatively movable in opposition to the second upper tool defines the outer portions of the wall 180 and includes protrusions to define the recesses 230 and 240 and a pin to define the supplementary water inlet 30. The main inlet side has a brass fitted non-return valve. Brass threaded inserts 250 are fitted to the outlet 40 and a plastic insert fitted to the supplementary water inlet 30. The plastic insert carries a non- return valve 110. The inserts include ³ A" British Standard Pipe Taper threads. The inserts are incorporated into the housing by over moulding.

Housing 80 is formed by first fitting the threaded inserts 250 to the pins which define the supplementary water inlet 30 and the outlet 40. The tool is then closed and the cavity defined by the tools is filled with liquid thermoplastic at about 25O ⁰ C. The tool bodies incorporate water galleries for cooling. After a short hold time the tool is opened and the finished housing 80 is ejected.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

It will also be understood that the term "comprises" (or its grammatical variants) as used in this specification is equivalent to the term "includes" and should not be taken as excluding the presence of other elements or features.