AU2011244897A1

AU2011244897A1 - Rain Water Harvesting

Info

Publication number: AU2011244897A1
Application number: AU2011244897A
Authority: AU
Inventors: Robert Sterland
Original assignee: Pentair Water Australia Pty Ltd
Current assignee: Pentair Water Australia Pty Ltd
Priority date: 2010-10-29
Filing date: 2011-10-31
Publication date: 2012-05-17
Anticipated expiration: 2031-10-31
Also published as: AU2011244897B2

Abstract

In one preferred form there is provided a rain water supply system (10) for supplementing mains water. The rain water supply system (10) includes a delivery facility (6) for 5 controlling the delivery of mains water (18) and the delivery of rain water (L2) to a water outlet (20). The rain water system (10) further includes a flow metering facility (22) having a flow origin facility (24) and a flow meter facility (26) that are adapted for allowing the determination of at least one volumetric characteristic (2]) that is associated with respective flows of mains water and flows of rain water through the 10 water outlet (20). Fig.1I 14 22 (I f ----- K30

Description

P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Invention Title: Rain Water Harvesting The following statement is a full description of this invention, including the best method of performing it known to me: 2316353vl RAIN WATER HARVESTING FIELD OF THE INVENTION The present invention relates to rain water harvesting systems and methods. BACKGROUND To THE INVENTION 5 In the field of rain water harvesting, systems and methods are used to supplement mains water. Generally in these systems mains water is disconnected and rain water is delivered to a water outlet when the level of rain water in a rain water tank is sufficiently high. The present inventors have realised that conventional rainwater systems for supplementing mains water suffer from a number of disadvantages. It is against this 10 background and the problems and difficulties associated therewith that the present invention has been developed. SUMMARY OF THE INVENTION According to a first aspect of preferred embodiments herein described there is provided a rain water supply system for supplementing mains water, the system comprising: a 15 delivery facility for controlling the delivery of mains water and the delivery of rain water to a water outlet; and a flow metering facility having a flow origin facility and a flow meter facility adapted for allowing the determination of at least one volumetric characteristic that is associated with respective flows of mains water and flows of rain water through the water outlet. 20 Preferably the rain water supply system includes a control facility for recording information associated with the respective flows of mains water and flows of rain water through the water outlet and for determining the at least one volumetric characteristic. According to a second aspect of preferred embodiments herein described there is provided a rain water supply system for supplementing mains water where the system 25 comprises: a flow arrangement having a mains water inlet, a rain water inlet, and a water outlet; the flow arrangement further including a flow meter facility adapted to provide an indication of the rate of change of the water flow rate and a delivery control facility for allowing the control of the delivery of water in response thereto.

2 Preferably the rain water supply system further comprises a pump for delivering rain water to the rain water inlet wherein the pump is adapted to be coupled to the delivery control facility of the flow arrangement such that the flow arrangement is able to control the delivery of rain water by the pump in response to the rate of change of the water flow 5 rate. According to a third aspect of preferred embodiments herein described there is provided a rain water management system for controlling a pump for delivering mains water, the rain water management system including an input facility for use in monitoring the rate of change of the flow rate and an output facility for controlling the pump as a result of 10 information received by the input facility. Preferably metering the flow comprises metering the flow from the water outlet and According to a fourth aspect of preferred embodiments herein described there is provided a method of supplementing mains water comprising: controlling the delivery of mains water to a water outlet; controlling the delivery of rain water to a water outlet; metering 15 the flow of water to the water outlet, and determining at least one volumetric characteristic associated with respective flows of mains water and flows of rain water. Preferably metering the flow comprises metering the flow from the water outlet and determining the origin of the flow. According to a fifth aspect of preferred embodiments herein described there is provided a 20 method of supplementing mains water comprising: controlling the delivery of mains water to a water outlet; controlling the delivery of rain water to a water outlet using a pump; and determining an indication of the rate of change of the water flow rate using a flow rate metering facility; wherein controlling the delivery of rain water to a water outlet using the pump comprises controlling the delivery of rain water in response to the flow 25 rate metering facility. Preferably determining the rate of change of water flow using a flow rate metering facility comprises determining the rate of change of mains water flow and determining the rate of change of rain water flow using a single flow meter. According to a sixth aspect of preferred embodiments herein described there is provided a 30 method of supplementing mains water comprising: controlling the delivery of mains 3 water to a water outlet; controlling the delivery of rain water to a water outlet using a pump; and determining an indication of remaining rain water flow based on at least one characteristic of the water flow rate; wherein controlling the delivery of rain water to a water outlet using the pump comprises controlling the delivery of rain water in response 5 to estimated remaining rain water flow. It is to be recognised that other aspects, preferred forms and advantages of the present invention will be apparent from the present specification including the detailed description, drawings and claims. BRIEF DESCRIPTION OF DRAWINGS 10 In order to facilitate a better understanding of the present invention, several preferred embodiments will now be described with reference to the accompanying drawings, in which: Figure 1 provides a schematic view of a rain water supply system according to a first preferred embodiment of the present invention; 15 Figure 2 provides a schematic view of a flow meter facility used in the rain water supply system shown in Figure 1; Figure 3 provides an exploded view of the flow meter facility shown in Figure 2; Figure 4 provides a graphical representation of mains flow to a toilet cistern using a conventional mains system; 20 Figures 5a and 5b provide graphical representations of the operation of a conventional rain water system that supplements mains water flow; Figure 6 to 9 provides illustrations of the operation of the rains water supply system shown in Figure 1; Figures 10 and I I provide views illustrating the flow where facility shown in 25 Figure 2; Figure 12 illustrates a method according to a further preferred embodiment of the present invention; and Figure 13 illustrates yet another method according to a preferred embodiment of the present invention; 30 4 DETAILED DESCRIPTION OF THE EMBODIMENTS It is to be appreciated that each of the embodiments is specifically described and that the present invention is not to be construed as being limited to any specific feature or element of any one of the embodiments. Neither is the present invention to be construed as being 5 limited to any feature of a number of the embodiments or variations described in relation to the embodiments. Referring to Figure 1 there is shown a rain water supply system 10 according to a first preferred embodiment of the present invention. The rain water supply system 10 is considered to be able to be advantageously used in supplementing mains water with rain 10 water from a rain water tank 12. The rain water supply system 10 advantageously provides a domestic rain water supply system in which there is provided a display facility 14. The rain water supply system 10 includes a delivery facility 16 for controlling the delivery of mains water from a mains water source 18 to a water outlet 20 as well as for controlling the delivery of rain water 15 from the rain water tank 12 to the same water outlet 20. The rain water supply system 10 includes a flow metering facility L having a flow origin facility 24 and flow meter facility 2. The flow origin facility 24 and flow meter facility 26 are together adapted to allow the determination of at least one volumetric characteristic 28 that is associated with respective flows of mains water from the mains water source 18 20 and flows of rain water from the rain water tank 12, through the water outlet 20. The at least one volumetric characteristic is advantageously able to be displayed on the remote display facility 14. In this embodiment the remote display facility 14 comprises a hand-held display that is able to be mounted on a wall or be readily carried in a person's pocket. 25 The flow metering facility 22 is coupled to a control and communications facility 30 that is adapted to send information to the display facility 14. The control and communications facility 30is adapted to record information where the information is associated with the respective flows of mains water and the flows of rain water through the water outlet 20. In addition to recording information, the control and communications facility 30 is able to 5 use the information to advantageously determine and display the at least one volumetric characteristic 28. In distinction from conventional systems such as disclosed in AU2003262296, to Davey Products Pty Ltd, the provision of the flow origin facility 24, the flow meter facility L 5 and the display facility 14 is considered to be advantageous as it allows for the measurement and display of advantageous water usage information related to, in particular, both flows of mains water from the mains water source 18 and flows of rain water from the rain water tank 12 through the water outlet 20. Presently there is considered to be no such arrangement available for use by households and other 10 establishments that provides such advantageous results. In this embodiment the at least one volumetric characteristic 28 includes a projected annual rain water flow consumption that advantageously allows the end user to estimate water savings for a year. In addition, the water use of the household or other establishment can be readily 15 displayed using the display facility 14 thereby making the user aware of the water usage and allowing the user to change the associated water consumption and assign resources accordingly. As a consequence of the advantages provided, it is considered that the rain water supply system 10 will ultimately result in water savings for households and other establishments. 20 As shown in Figure 1, the delivery facility 16 includes a flow arrangement 32 providing a flow arrangement mains water inlet 34 for receiving mains water from the mains water source 18, a flow arrangement rain water inlet 36 for receiving rain water from the rain water tank 12 and a flow arrangement outlet 38 for the delivery of water directly to the water outlet 20. 25 As shown in Figure 2 the delivery facility 16 includes a rain water inlet valve arrangement 35, in the form of a single non-return valve, for preventing the return of mains and pumped tank water to the rain water tank 12. A mains water inlet valve arrangement 37, in the form of a dual non-return valve system is provided to, in particular, prevent the return of house/tank water to the mains supply system.

6 Moreover, the flow origin facility 24 comprises a flow origin communication facility 40 forming part of the flow arrangement 32 for providing information indicative of whether the flow arrangement outlet 38 is in fluid communication with the mains water inlet 34 or is in fluid communication with the rain water inlet 36. 5 The flow origin communication facility 40 forms part of the control and communications facility 30 as does a flow meter communications facility 42 provided by the flow meter facility 26. The flow meter communications facility 42 is advantageously adapted to provide information indicative of water flow from the flow arrangement outlet 38. In this embodiment the flow meter communications facility 42 is adapted to send details of the 10 flow rate through the flow arrangement outlet 38 which by virtue of the arrangement of the system directly corresponds with the water flow rate through the water outlet 20. As illustrated in Figure 2, the control and communications facility 30 includes a single wireless transmitter 44 for transmitting information in the form of one or more signals 46 based on information from the flow origin communication facility 40 and the flow meter 15 communications facility 4. The control and communications facility 30 also includes a a micro controller and storage facility 45 for storing recorded information. The signals are advantageous received by the display facility 14 which displays information based on the data sent from the control and communications facility 30. In this embodiment the control and communications facility 30 records data over an 20 extended period of time and utilises a determination component to advantageously determine the at least one volumetric characteristic 28. It is to be appreciated that the flow arrangement 32 provides an embodiment of the present invention its own right. The flow arrangement 32 is configured to provide the flow arrangement mains water inlet 34 in-line with the flow arrangement outlet 38 to 25 allow ready fitting of the flow arrangement 32 to existing mains water connections and ready installation of the domestic rain water supply system _0 in general. As more clearly shown in Figure 3, the flow meter facility 26 of the flow arrangement 32 comprises a single turbine meter 48 that is able to be advantageously used together with the flow origin facility 24 to measure both the delivery of mains water from the mains 7 water source 18 to the water outlet 20 and the delivery of rain water from the rain water tank 12 to the water outlet 20. Advantageously the flow arrangement 32 includes a delivery control facility 50 for allowing control of the delivery of water in response to the rate of change of the flow rate 5 as determined using the single turbine meter 48. As shown in Figure 1, the delivery control facility 50, in this embodiment is coupled to a controller 52 via a wired link 54. The controller 52 is advantageously adapted to stop a pump L from supplying rain water from the rain water tank 12 to the rain water inlet 36 of the flow arrangement 32. Switching to the rain water tank 12 is achieved using a single solenoid valve 58. In this 10 embodiment the controller 52 forms part of an electric motor 60 that drives the pump 5. A wired link 57 is provided between the control and communications facility 30 and a level reader 62 in the rain water tank 12. The level reader 62 forms part a rain water level facility _6 for determining the level of rain water in the rain water tank 12. In this embodiment the control and communications facility 30 monitors the level of water in the 15 rain water tank 12 using the level reader 62 and the level reader 62 derives its power directly from a mains power connection (not shown). As would be apparent various forms of level reader could of course be employed in the rain water supply system 10. The use of wireless links is also feasible. The control and communications facility 30 is advantageously adapted to query the 20 solenoid 58. More particularly, a fault monitoring facility within the flow arrangement 32 queries the controller 52, the solenoid valve 58 and the turbine meter 48 to determine fault conditions. In one mode of fault querying the control and communications facility 30 activates and deactivates the solenoid valve 58 and the pump 5 and determines a fault condition from the response of the turbine meter 48. Other forms of more complicated 25 fault monitoring are of course possible. In this embodiment, the provision of the flow arrangement 32 is itself considered to be advantageous for a number of reasons. Firstly the flow arrangement 2 provides a system that can be readily installed with the delivery control facility 50 allowing for the controlled delivery of rain water in response to an indication of the rate of change of the 30 water flow rate provided by the turbine meter 48.

8 In the domestic rain water supply field there are a number of advantages provided by the flow arrangement 3. Unlike a flow switch as used in conventional arrangements such as in AU2003262296 to Davey Products Pty Ltd, the turbine meter 48 does not only register two stages of water flow. Rather with the use of the turbine meter 48, the flow meter 5 arrangement 26 is advantageously able to predict decaying flow demand in particular circumstances such as when refilling a toilet cistern. In order to illustrate the advantage it is first necessary to appreciate that with a conventional flow switch a plunger is typically placed in the path of the water and allowed to move back and forth. When the water flow reaches a certain flow, the plunger 10 moves and a magnetic reed switch closes. The information provided by the reed switch corresponds with a threshold and is used to determine a first state of operation (on) and a second operation state (off). With a typical rain water system the flow switch turns off the pump 56 when the flow switch moves to the off state, where the off state corresponds with a low flow. 15 In the case of mains supplying a toilet cistern the flow would stop at point 66 shown in Figure 4. The operation of a conventional rain water system that supplements mains water flow is illustrated in Figures 5a and 5b. In such a conventional system there would typically be an initial flow from the mains supply until the flow switch detects a flow threshold having a flow rate 68 illustrated in Figure 5a. The flow switch would then 20 activate the pump 56 after time 70. The rain water supply would then take over from the mains water supply. The cistern would subsequently fill until the flow switch again detected the flow threshold having the associated flow rate 68 at time point_7 . At this time the flow switch would deactivate the pump 56 with the mains water 'effectively' serving to fill the remaining volume of the cistern. As would be apparent the 25 pipes are considered to have zero volume. Providing a discussion accounting for pipe volumes would merely complicate matters with no real effect as all piping volumes are effectively lost to the system. This noted, the conventional flow switch arrangement would provide, a first mains volume 72, a first rainwater volume 74 and a second mains volume 76 that effectively fill 30 the cistern. Given that mains water has an associated cost, the provision of mains water to fill the cistern is generally undesirable.

9 In order to reduce the second mains volume 76 some conventional systems continue to run the pump 56 for a set time after the flow switch has moved to an off state. The use of such system still often however results in mains water having to be provided in some circumstances where there are various flow curves and, even if this is not the case, in 5 wasted electricity with the pump being unable to pump water into the cistern when there is no demand. With the rain water supply system 10, however, these disadvantages are advantageously addressed. More particularly the delivery control facility 5 includes a flow determination facility 78 that is advantageously able to determine a desirable time cut off approximating the actual 10 time point 66. As illustrated in Figure 6, and as described in further detail with respect to Figure 9 below, a desirable time cut off 80, is determined by calculating derivatives of the flow rate with respect to time as represented by a number of lines 82. With the present system the desirable time cut off 80 closely approximates the cistern cut off time point 66. Thus, the flow determination facility 78 uses the flow rate and one or more derivatives 15 thereof to estimate an advantageous pump cut off time. The system is considered to be particularly advantageous as it can be applied to different cistern flow rate demand curves such as the flow rate curve 84 shown in Figure 7. As would be apparent the problems of mains water wastage would be particular pronounced in the case of the flow rate curve 86 of Figure 6 as the flow rate is dropping 20 more slowly than is the case with flow rate curve 84. Even in this case, the desirable cut off time 80 is so close to the cistern cut off 66 that the pump 56 is not switched off that prematurely so as to result in much wasted mains water. Neither, is the pump is not switched off that belatedly so as to result in much wasted electricity. The flow determination facility 78 is advantageously configured to account for exponential decay 25 associated with cisterns and other systems. The flow determination facility 78 is also adapted to address an abruptly decreasing water demand such as may be experienced with a washing machine, garden watering system and other devices. As shown in Figure 8, by detecting a rapid decrease in the flow rate, even at a relatively high flow rate 88, the flow determination facility 78 can 30 advantageously determine a relatively accurate time cut off 90 to control the pump 56 to substantially minimize both mains water and pump electricity use.

10 In this embodiment, the determination facility 8 is advantageously configured to use several estimation methods based on predetermined curve shape characteristics for a variety of domestic configurations. More particularly, the determination facility 78 is entirely preconfigured and automated. Of course in other embodiments, an interface may 5 be provided for configuring the determination facility for particular rains water applications for supplementing the mains water supply. In the case of the cistern example shown of Figure 9, the determination facility 78 is advantageously adapted to determine when then flow rate is approaching a level Fo 92 based on a predetermined threshold. At this point the determination facility 78 10 determines a zero flow time according to the formula. To= - Fo / (dF(t)/dt) ; where To = estimated time of zero flow 94 ; Fo= flowrate 92; and dF(t)/dt = rate of change of flow rate 96 at Fo. The value calculated by the determination facility 78 is then used as the cut off time. In 15 other embodiments several approximation techniques based on exponential decay are employed to further refine the expected time To. Other conventional rain water supply systems use a pressure switch, as opposed to a flow switch. In the case of a pressure switch off the shelf units are typically used to detect water demand. The pressure control switch is typically connected to the to the pump 20 being either being wired in parallel with a solenoid valve for connection to the mains or being connected to the mains via a 3-way pressure overriding valve. As with flow switches pressure switches suffer from mains water wastage represented by the first mains volume 72 shown in Figure 5b. With conventional pressure switch arrangements they notably tend to continue to feed 25 mains water when the water demand at the water outlet commences due to a substantial pressure drop being required to start the pump. Advantageously, with the present embodiment this problem is addressed as the turbine meter 48 provides an almost instantaneous measurement of commencing flow allowing for rapid activation of the pump 5. This consequently serves to limit the size of the first mains volume 72.

1 Pressure overriding valves also have the disadvantage that they can result in mixing of rain and mains water depending, of course, on the mains pressure. The present inventors consider that the use of the turbine meter 48 is particularly advantageous as a result of the impeller blades of the turbine meter 48 beginning to spin 5 almost instantaneously when there is a water flow. In this embodiment, the turbine meter 48 has magnets embedded into the outer ring of its impeller. The magnets pass by a magnetic sensor located in the proximity of the propeller. The magnetic sensor recognises the flow as a series of voltage pulses. The frequency of the voltage pulses varies with the speed of the flow such that the faster the flow, the higher the frequency of 10 the pulses. The voltage pulses are passed from the magnetic sensor onto the microcontroller. Software in the microcontroller uses the pulses from the magnetic sensor as input to control decisions as to the operation of the pump 56. It is to be appreciated that the flow arrangement 32 itself provides an advantageous system according to the present invention. In the flow arrangement 32, there is provided 15 a flow arrangement mains water inlet 34, the flow arrangement rain water inlet 36 and the flow arrangement outlet 38. The flow meter facility 2 in the form of the turbine meter 48 is advantageously adapted to measure the rate of change of water flow. The flow meter arrangement 32 advantageously includes the delivery control facility 50 for allowing the control of the delivery of water in response thereto. The pump 5 is coupled 20 to the delivery control facility 50 such that the flow arrangement 32 is able to control the delivery of rain water by the pump 56 in response to the rate of change of water flow. Various agitation conditions at the pump stat up has meant that the applicant is able to determine a flow rate of about 1.51/minute using the turbine meter 48. During slow down flow the applicant believes that a flow rate of 0.8 /minute should be able to be 25 determined. Various increased flow rate measurement sensitivities could of course be provided. The precise configuration of the flow meter arrangement 32 is illustrated in Figures 10 and 11. The following table of parts illustrates the respective components for ease of reference. 30 Table of Components 12 (201) Integrated Body 707501 1 (202) Hydraulic Assembly EndCaps 707506 3 (203) Filter 1 inch 707509 2 (204) Check valve Assembly 3 5 (204a) Outer o-ring 3 (204b) Check valve Shutoff Guide 707508 3 (204c) Seal Washer 3 (204d) Check Valve Shutoff 707507 3 (204e)/36 Turbine Flowmeter Assembly 707510 1 10 (205a) Turbine Wheel 3 (205b) End Bearing 3 (205c) Turbine Shaft Support 707513 1 (205d) Turbine Shaft 707512 1 (205e) Turbine Housing 707511 1 15 (206) 12V DC Coil Assembly I (206a) 12V DC Coil I (206b) 25mm Normally Open Plunger 707505 1 (206c) Intermediate Retainer 707519 1 (206d) Floating Plunger Tip Normally Open 1 20 (207) 25mm Solenoid Lid Assembly 1 (207a) 25mm Normally Open Lid 707504 1 (207b) 1 inch Disk Diaphragm 1 (208) O-Ring 2.62mm Dia. 1 (209) Screws 8 x 18mm 27 25 (210) Flowmeter Sensor Assembly 707515 1 13 (210a) Sensor Shell 707517 1 (21 Ob) Sensor Nymet 707516 1 (210c) Waterswitch Sensor 707518 1 (211) Waterswitch Cover without Rails 707502 1 5 (211) Waterswitch Cover with Rails 707503 1 (212) Hydraulic Assembly 707500 1 As shown in Figures 10 and 11, the flow arrangement 32 comprises a housing 98 that houses the flow meter facility 26 as well as providing the mains water inlet 34, the rain 10 water inlet 36, and the water outlet 38. The housing 98 comprises the lower integrated body 201 that houses the flow meter facility 2 as well as the upper cover 211 that covers the solenoid assembly. The lower integrated body 201 is designed such that the mains water inlet 34 is in-line with the water outlet 38 to allow ready fitting of the flow arrangement 32 to an existing 15 mains water connection. The assembled flow meter arrangement 32 less the upper cover 211 is shown in Figure 8. A method 100 of supplementing mains water according to a further preferred embodiment of the present invention is illustrated in Figure 12. At block 102 the method comprises controlling the delivery of mains water 104 from a mains water source 106 to a water 20 outlet 108 . At block _10 the method 100 includes controlling the delivery of rain water 112 from a rain water tank 114 to the water outlet 108. In the method 100, controlling the delivery of water is selective such that when there is a flow of mains water 104 from the mains water source 106, there is no flow of rain water 112 from the rain water tank 114. Similarly when there is a flow of rain water 112 from the rain water tank 114 there is no 25 flow of mains water 104 from the mains water source 106. At block 116 the method 100 includes metering the flow of mains water 104 from the mains water source 106 as well as metering the flow of rain water 112 from the rain water tank 114 as the case may be, to the water outlet 108.

14 At block 118 the method includes determining at least one volumetric characteristic 120 associated with respective flows of mains water 104 and flows of rain water 112 over an extended period of time 122. Metering the flow at block 116 advantageously includes determining the origin of the flow at block 124 . 5 The method 100 also advantageously stores integrated flow rate measurements to provide a cumulative total during the alternating times water is sourced from the mains water source 106 and the rain water tank 114. Measuring the water use allows the user to understand the way in which water is being used in the household or commercial premises and to adjust their behaviour accordingly in order to save water or to allocate 10 additional resources where necessary. In measuring the cumulative flow the following formula is used: CFms=ZF(t)*(a=mainson)At; and CFrw=F(t)(a=rw on)At where CFms is the cumulative flow of mains water; F(t) is the flow rate recorded at time t; and a= a recorded parameter indicating mains or rain water flow; and At is the F(t) 15 recordal period. As such this method measures the flow rate at regular intervals and takes an integral of the flow rate. Another method that may be applied comprises measuring repeating pulses from the magnetic sensor of the turbine flow meter and with each one or more pulses adding a certain volume to the corresponding cumulative total where each pulse 20 represents the passing of a certain volume of water. Referring to Figure 13, there is shown a method 126 of supplementing mains water according to a further preferred embodiment of the present invention. At block 128 the method 126 comprises controlling the delivery of mains water 130 from a mains water source 132 to a water outlet 134. At block 136 the method 126 includes controlling the 25 delivery of rain water 138 from a rain water tank 140 to the water outlet 134 using a pump 142. The method 126, at block 144, further includes determining the rate of change of the water flow rate using a flow rate metering facility 146. In the method, at block 136, controlling the delivery of the rain water 138 to the water outlet 134 using the pump 142 comprises, at block 148, controlling the delivery of rain water in response to the rate 15 of change of the water flow rate determined by the flow rate metering facility 146 at block 144. In the method 126 determining the rate of change of the water flow rate using the flow rate metering facility 146 comprises determining the rate of change of mains water flow 5 rate from the mains water source 132 as well as determining the rate of change of rain water flow rate from the rain water tank 140 using a single flow meter. The method at block 150 further includes monitoring the level of rain water in the rain water tank 140 and delivering mains water from the mains water source 132 as required. The method 126 uses a single flow meter to determine the actual flow passing through the 10 water outlet 134. By taking measurements of the flow rate at regular intervals the change in flow over time is advantageously determined and the pump is advantageously controlled in anticipation of water demand. The system operates to prevent mains water wastage when the flow is increasing and decreasing. In the method 126, when the flow rate of rain water from the rain water tank is seen to be dropping towards a zero demand 15 condition, the method 126 uses the characteristics of the rate of change of the flow rate to determine how long the rain water pump 142 needs to run. The method 126 is advantageously adapted to accommodate the filling of cisterns having exponential decay characteristics, washing machines having abrupt decay characteristics and other devices. 20 In the method 126, information on water use is relayed to a remote handheld display device 152 via a wireless link 154. Water usage data associated with the household or business is constantly and readily available from the remote display device 152 making the user aware of the corresponding water usage and allowing the user to change his or her behaviour and possibly allocate resources accordingly. Ultimately it is considered 25 that any resulting change in behaviour will provide water saving advantages. Furthermore, any unusual change detected in the water usage may alert the user to a problem with the rain water system. In the method a controller continuously relays information to a transmitter module where the information comprises the status of the system, the level of water in the tank, and the 30 water flow rate at that point in time with details of any fault conditions. The transmitted 16 signal is displayed in the remote hand held display device 152 which shows the user the information transmitted and other information determined thereform. The user is relatively immediately informed of any fault conditions using an SMS facility built into the remote hand held display device 152. On viewing the remote hand held 5 display device the nature of the fault is indicated allowing the user to reset the device, make a service call or change the configuration of the system. Users of conventional rain water systems for supplementing mains water are considered to seldom check the operation of their systems meaning that fault conditions can go unnoticed for days, weeks or even months before the fault is detected. This is undesirable as it often results in much 10 wasted water. Although there are many possibilities real-time flow rates are preferably able to be displayed on the display device 152 in units of litres per second or litres per minute. Projected and actual cumulative totals are preferably able to be shown as litres per day litres per month and litres per annum. As would be apparent, various alterations and equivalent forms may be provided without 15 departing from the spirit and scope of the present invention. This includes modifications within the scope of the appended claims along with all modifications, alternative constructions and equivalents. There is no intention to limit the present invention to the specific embodiments shown in the drawings. The present invention is to be construed beneficially to the applicant and 20 the invention given its full scope. In the present specification, the presence of particular features does not preclude the existence of further features. The words 'comprising', 'including' and 'having' are to be construed in an inclusive rather than an exclusive sense. It is to be recognised that any discussion in the present specification is intended to explain 25 the context of the present invention. It is not to be taken as an admission that the material discussed formed part of the prior art base or relevant general knowledge in any particular country or region.

Claims

1. A rain water supply system for supplementing mains water, the system comprising: a delivery facility for controlling the delivery of mains water and 5 the delivery of rain water to a water outlet; and a flow metering facility having a flow origin facility and a flow meter facility adapted for allowing the determination of at least one volumetric characteristic that is associated with respective flows of mains water and flows of rain water through the water outlet. 10

2. A rain water supply system as claimed in claim I wherein the rain water supply system includes a control facility for recording information associated with the respective flows of mains water and flows of rain water through the water outlet and for determining the at least one volumetric characteristic.

3. A rain water supply system as claimed in claim 2 wherein the delivery facility 15 comprises a flow arrangement providing a mains water inlet for receiving the mains water, a rain water inlet for receiving the rain water, the flow arrangement further providing a flow arrangement outlet for delivering water to the water outlet, with the flow origin facility comprising a flow origin communication facility coupled to the flow arrangement for providing 20 information indicative of whether the flow arrangement outlet is in fluid communication with the mains water inlet or is in fluid communication with the rain water inlet.

4. A rain water supply system as claimed in claim 3 wherein the flow meter facility comprises a flow meter communications facility for providing 25 information indicative water flow from the flow arrangement outlet.

5. A rain water supply system as claimed in claim 4 wherein the supply system includes a transmitter for transmitting information in the form of one or more 18 signals based on information from the flow origin communication facility and the flow meter communication facility.

6. A rain water supply system as claimed in any one of claims 2 to 5 wherein the mains water inlet is in-line with the flow arrangement water outlet to allow 5 ready fitting of the flow arrangement to an existing mains water connection.

7. A rain water supply system as claimed in any one of claims 2 to 6 wherein the flow meter facility comprises a single turbine meter that is able to be used together with the flow origin facility to measure both the delivery of mains water to the water outlet and the delivery of rain water to water outlet. 10

8. A rain water supply system as claimed in claim 7 including a delivery control facility for allowing the control of the delivery of water in response to an indication of the rate of change of the flow rate determined using the turbine meter.

9. A rain water supply system as claimed in any one of claims 2 to 8 wherein the 15 flow arrangement includes a single solenoid valve.

10. A rain water supply system as claimed in any one of claims 2 to 9 wherein the central facility comprises a remote unit including a display facility for displaying said at least one volumetric characteristic in response to a user request. 20

11. A rain water supply system as claimed in any one of claims 2 to 10 wherein the at least one volumetric characteristic comprises a characteristic associated with an extended period of time such as a litres per day, litres per month or litres per year characteristic for both the flow of mains water and the flow of rain water. 19

12. A rain water supply system as claimed in any one of claims I to 11 including a fault monitory facility for detecting errors in the delivery facility and the flow metering facility.

13. A rain water supply system as claimed in any one of claims I to 10 including a 5 rain water level facility for determining the level of rain water in a water tank from which the rain water is delivered.

14. A rain water supply system for supplementing mains water where the system comprises: a flow arrangement having a mains water inlet, a rain water inlet, and a water outlet; the flow arrangement further including a flow meter 10 facility adapted to provide an indication of the rate of change of the water flow rate and a delivery control facility for allowing the control of the delivery of water in response thereto.

15. A rain water supply system as claimed in claim 14 wherein the system further comprises a pump for delivering rain water to the rain water inlet wherein the 15 pump is adapted to be coupled to the delivery control facility of the flow arrangement such that the flow arrangement is able to control the delivery of rain water by the pump in response to the rate of change of the water flow rate.

16. A rain water supply system as claimed in claim 14 or 15 wherein the flow 20 arrangement comprises a housing adapted to house the flow meter facility as well as provide the water inlet, the rain water inlet and the water outlet.

17. A rain water supply system as claimed in claim 16 wherein the housing comprises an upper part and a lower part, with the lower part providing the mains water inlet, the rain water inlet and the water outlet, the lower part also 25 housing the flow meter facility. 20

18. A rain water supply system as claimed in any one of claims 14 to 17 wherein the mains water inlet is in-line with the water outlet to allow ready fitting of the flow arrangement to an existing mains water connection.

19. A rain water management system for controlling a pump for delivering mains 5 water, the rain water management system including an input facility for use in monitoring the rate of change of the flow rate and an output facility for controlling the pump as a result of information received by the input facility.

20. A method of supplementing mains water comprising: controlling the delivery of mains water to a water outlet; controlling the delivery of rain water to a 10 water outlet; metering the flow of water to the water outlet, and determining at least one volumetric characteristic associated with respective flows of mains water and flows of rain water.

21. A method as claimed in claim 20 wherein metering the flow comprises metering the flow from the water outlet and determining the origin of the flow. 15

22. A method of supplementing mains water comprising: controlling the delivery of mains water to a water outlet; controlling the delivery of rain water to a water outlet using a pump; and determining an indication of the rate of change of the water flow rate using a flow rate metering facility; wherein controlling the delivery of rain water to a water outlet using the pump comprises 20 controlling the delivery of rain water in response to the flow rate metering facility.

23. A method as claimed in claim 22 wherein determining the rate of change of water flow using a flow rate metering facility comprises determining the rate of change of mains water flow and determining the rate of change of rain 25 water flow using a single flow meter.

24. A method as claimed in claim 22 or 23 including measuring the level of rain water in a water tank 21

25. A method as claimed in any one of claims 22 to 24 including determining fault codes.

26. A method of supplementing mains water comprising: controlling the delivery of mains water to a water outlet; controlling the delivery of rain water to a 5 water outlet using a pump; and determining an indication of remaining rain water flow based on at least one characteristic of the water flow rate; wherein controlling the delivery of rain water to a water outlet using the pump comprises controlling the delivery of rain water in response to estimated remaining rain water flow. 10

27. A system substantially as herein described with reference to the accompanying drawings.

28. A method substantially as herein described with reference to the accompanying drawings.