AU2005100775C4

AU2005100775C4 - Rainwater Harvesting

Info

Publication number: AU2005100775C4
Application number: AU2005100775A
Authority: AU
Inventors: Mark Andrew Lance; Hugh Barr Mcdonald
Original assignee: Davey Products Pty Ltd
Current assignee: Davey Water Products Pty Ltd
Priority date: 2002-11-20
Filing date: 2005-09-20
Publication date: 2006-05-25
Anticipated expiration: 2011-11-14
Also published as: AU2005101017A4; AU2005100775B4; AU2005100775A5; AU2005101017B4

Description

P/00/009A Section 29

AUSTRALIA

Patents Act 1990 INNOVATION PATENT SPECIFICATION Invention Title: RAINWATER HARVESTING Applicant: DAVEY PRODUCTS PTY. LTD.

The invention is described in the following statement: 2 Rainwater Harvesting This application is a divisional application of Australian Patent Application No.

2005204286, the entire contents of which are incorporated herein by reference.

The present invention relates to rainwater harvesting and in particular to a system suitable for automatically interfacing rainwater to a mains water supply network.

Rainwater harvesting systems are known. One such system is disclosed in EP 1201834 by Bogemar S.L. The known system includes an auxiliary storage tank that is filled with water from a mains network. A float valve maintains water in the auxiliary tank between preset levels. A three way electric valve is used to alternately establish a hydraulic connection between the inside of the auxiliary tank or a rainwater storage tank respectively and an inlet of a hydraulic pump. The hydraulic pump circulates water from the auxiliary tank or from the rainwater storage tank to a point of consumption.

One disadvantage of the prior art system is that a pump is required to deliver water not only from the rainwater tank but also from the mains network. The pump therefore has to run whenever water is being consumed, including when the rainwater tank is empty. This makes the pump more liable to breakdown. A breakdown in the pump or an associated control system or a power outage means that water cannot be drawn either from the storage tank or from the mains network.

The discussion of the background to the invention herein is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to was published, known or part of the common general knowledge in Australia as at the priority date of any of the claims.

An object of the present invention is to alleviate the disadvantages of the prior art or at the very least to provide consumers with a choice.

According to one aspect of the present invention, there is provided a system for supplementing a mains water supply with rainwater from a rainwater supply, said mains water supply not being an air-break supply, the system including: means for detecting demand from a consumer; means for detecting the presence of rainwater in the rainwater supply; a pump and a non-return valve provided in the rainwater supply, the pump delivering rainwater to said consumer via the non-return valve; a normally-open solenoid valve for blocking the mains water supply when closed; and W:\provs\DP754887Amds.doc V means for actuating the pump based on the detection of consumer demand

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Oand the detection of rainwater in the rainwater supply, so as to actuate the pump to (Ni deliver rainwater when rainwater above a minimum amount and consumer demand are detected, and also for actuating the solenoid valve based on the detection of consumer demand and the detection of rainwater in the rainwater supply so as to actuate the solenoid valve to block the mains supply when rainwater above a minimum amount and consumer demand are detected, said solenoid valve being held in an open state when no demand is detected.

According to a further aspect, the present invention provides a method of supplementing a mains water supply that is not an air-break supply with rainwater from a rainwater supply, the method including the steps of: Nproviding a pump and a non-return valve in the rainwater supply; providing a normally-open solenoid valve in the mains water supply; detecting demand from a consumer; detecting rainwater in the rainwater supply; and actuating the pump to deliver rainwater via the non-return valve when both consumer demand and at least a minimum amount of rainwater are detected; and actuating the normally-open solenoid valve to close in order to block the supply of mains water when both consumer demand and at least a minimum amount of rainwater are detected, said solenoid valve being held in an open state when no demand is detected.

The means for detecting demand may include a flow sensor. The means for detecting rainwater may include a water sensor. The water sensor may be provided by any means suitable for detecting presence of rainwater and/or a low level of water in an associated water storage tank. The rainwater may be delivered from the water storage tank. The water sensor may include a pressure sensor, float level switch, string resistor network (for comparative resistance measurement) or the like. The pressure sensor may be provided by any suitable means and may be located within a flange associated with the storage tank. The float level sensor may be provided by any suitable means and may be associated with a switch for actuating a hydraulic pump.

The pump may be located inside the water storage tank such that it is at least partly submerged when water is present in the tank or it may be located outside the tank such as in a cavity below the tank.

The means for actuating the pump may include a relay. The pump may be actuated when presence of rainwater is detected (preventing loss of prime for the W:\provsDP754887Amds.doc In pump) and the means for detecting demand detects flow of water above a

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Opredetermined threshold.

The control system is arranged such that an air break is not introduced in the mains water supply when rainwater is not being consumed.

The present invention may provide a system for interfacing stored water to a mains water supply in a manner which is relatively seamless from the point of view of a consumer. The system may be arranged such that it does not detract from the usual benefits associated with a conventional mains water supply network, at least when rainwater is not available or is not being used.

The system of the present invention may be arranged such that it may be easily overridden or switched off by the consumer to obtain water directly from the mains network.

The system of the present invention may provide an uninterrupted supply of water in the event of a failure of a pump or associated controller or in the event of a power outage.

The system of the present invention may be arranged to minimize running of the pump, eg. at least when demand is relatively low or in the event of a slow leak. In those circumstances water demand may be supplied directly from the mains water supply network. This arrangement not only extends pump life but also saves power.

Viewed from another aspect, the present invention provides apparatus for providing a consumer water network with a mains water supply and a rainwater supply, said mains water supply not being an air-break supply, the apparatus including means for detecting a consumer demand, means for detecting the presence of rainwater in the rainwater supply, and means for switching the input of the consumer system from the mains supply to the rainwater supply when customer demand and at least a minimum amount of rainwater are detected, the means for switching including a normally-open solenoid valve in the mains water supply, and a pump and non-return valve in the rainwater supply, the solenoid valve being energized to a closed state to block the mains water supply when the pump is activated to supply rainwater and being de-energized to an open state to enable supply of said mains water when demand is no longer detected and the pump is no longer activated.

Viewed from a further aspect, the present invention provides an interface unit for connection between a mains water supply, a rainwater supply and a consumer water network, the mains water supply being connected directly to the consumer water network without the use of an air break, the unit including: W: povsNDP754887Amds.doc 0 a mains water conduit for coupling to the mains water supply, the conduit 0 Ohaving a normally-open solenoid valve therein; a rainwater conduit for coupling to the rainwater supply, the rainwater conduit having a non-return valve therein; a conduit communicating with the mains water conduit and the rainwater conduit for connection to the consumer water network; and a controller for actuating the solenoid valve and a pump, the interface unit, in use, receiving rainwater from the pump via the non-return valve; wherein, in use, the controller actuates the pump and the solenoid valve so that when consumer demand and the presence of at least a minimum amount of rainwater are detected, the pump is actuated to supply rainwater and the solenoid valve is Nclosed to block the mains water supply, and so that when there is less than a minimum amount of rainwater or there is no demand, said pump is not actuated and said solenoid valve is open to enable supply of mains water.

Viewed from another aspect, the present invention provides apparatus for providing a consumer with a mains water supply and a rainwater supply, the mains water supply not being an air-break supply, the apparatus including means for detecting consumer demand and the presence of rainwater in the rainwater supply, and means for switching from the mains water supply to the rainwater supply when consumer demand and the presence of at least a minimum amount of rainwater are detected, the means for switching including a normally open solenoid valve in the mains supply, a pump and non-return valve in the rainwater supply and relay means for actuating the solenoid valve and pump, wherein when consumer demand and the presence of at least a minimum amount of rainwater are detected, the pump is actuated to supply rainwater to the consumer via the non-return valve and the solenoid valve is energized to a closed state to block the mains water supply, and wherein when there is no demand, the pump is not actuated and the solenoid valve is not energized and is in an open state to enable the supply of mains water.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings wherein: FIG. 1 shows a diagram of a rainwater harvesting system according to one embodiment of the present invention; FIG. 2 shows the system in FIG. 1 with a full tank and wherein water demand is above a predetermined threshold; FIG. 3 shows the system in FIG. 1 with a full tank and wherein water demand is below the predetermined threshold; W:\provs\DP754887Amds.doc FIG. 4 shows the system in FIG. 1 with an empty tank and wherein demand is being satisfied by the mains supply network; FIG. 5 shows a wiring diagram associated with the system shown in FIGs. 1 to 4; FIG. 6 shows a diagram of another rainwater system not being an embodiment, but showing possible system modifications; FIG. 7 shows a modification of the rainwater system shown in FIG. 6; FIG. 8 shows a wiring diagram associated with the system shown in FIGs. 6 and 7; and FIG. 9 shows a cut away view of another rainwater harvesting system.

The rainwater harvesting system shown in FIG. 1 includes a storage tank for rainwater. Tank 10 is adapted to store storm water collected from a catchment means such as a roof of a building (not shown) via downpipe 11.

Water is drawn from tank 10 via flange 12. Hydraulic pump 13 is in fluid communication with flange 12 via an inlet conduit 14. Hydraulic pump 13 also is in fluid communication with one terminal of T-section coupling 16 via outlet conduit 15. Outlet conduit 15 is connected to the one terminal of T-section coupling 16 via non-return valve 17. The mains supply network is connected to another terminal of T-section coupling 16 via non-return valve 18 and normally open solenoid valve 19.

Consumer demand is sensed via flow sensor 20. Flow sensor includes a preset threshold so that small leaks and the like do not cause unnecessary running of pump 13. Pump 13 is actuated via controller 21.

Controller 21 receives signals from flow sensor 20 and pressure sensor 22 located in flange 12. Flange 12 is positioned above base 23 of tank 10 to avoid drawing sediment and other debris which may find its way into tank Pressure sensor 22 detects an acceptable head of water in tank 10 to avoid loss of prime in pump 13. Alternatively pressure sensor 22 may be positioned in a conduit upstream of pump 13 such as inlet conduit 14. Alternatively pressure sensor 22 may be replaced with a float level sensor/switch (not shown) located inside tank 10. The switch associated with the float level sensor may be adapted to actuate pump 13 when the quantity of water in tank 10 is above a predetermined minimum level. In some embodiments pump 13 may be W:\pmvs\DPnnovOivRairratertarv estingdoc submersible and may also be located inside tank 10. The float level sensor/switch may be attached to or integrated with the submersible pump.

When pressure sensor 22 detects that there is sufficient water above a preset level) in tank 10 and flow sensor 20 detects demand for water from a consumer above a preset threshold, controller 21 is arranged to close normally open solenoid valve 19 and to actuate pump 13. Closure of solenoid valve 19 causes water from the mains network to be cut off whilst actuation of pump 13 causes water to be drawn from tank 10 and pumped to the consumer via conduit 15, non-return valve 17 and T-section coupling 16.

FIG. 2 shows the system with sufficient water in tank 10 and wherein demand flow has been detected that is above a predetermined threshold, causing water to be drawn from tank 10 and supplied to the consumer in preference over the mains supply network.

FIG. 3 shows the system with sufficient water in tank 10 and wherein demand flow has been detected that is below the predetermined threshold.

Controller 21 has not actuated pump 13 and demand is supplied by the mains supply network avoiding unnecessary running of pump 13. One example of this includes a final stage of a toilet cistern filling cycle.

FIG. 4 shows the system with insufficient water in tank 10. Irrespective of the level of demand flow, controller 21 will not actuate pump 13 because pressure sensor 22 has detected low pressure in flange 12. Demand is therefore supplied by the mains supply network.

Advantageously, in the event of a power outage or failure of pump 13, controller 21 or sensor 20 or 22, water is seamlessly available from the mains supply network. Even when sufficient water is available from tank 10, the consumer may elect to override the rainwater harvesting system by disabling controller 21 via a suitable switch or the like (not shown).

FIG. 5 shows a wiring diagram associated with the rainwater harvesting system of FIGs. 1 to 4. The system includes a controller (relay) 21 actuated via normally open flow switch 20 and normally open pressure switch 22 connected in series. When pressure switch 22 is closed denoting that water level in tank is above a predetermined threshold and flow switch 22 is closed denoting that water demand or flow is above a predetermined threshold, power from the AC mains is applied to controller (relay) 21 tripping it. When controller (relay) W:\pmvs\OPInnovDvRaHnwaterHarvesting.doc 8 21 is tripped it supplies power to normally open solenoid 19, causing it to close and block supply of water from the mains network. Controller (relay) 21 also supplies power to pump 13 causing it to run and to pump water from tank 10 to the consumer.

FIG. 6 shows a modification of the rainwater harvesting system in FIG. 1 wherein solenoid valve 19 is replaced with pressure reducing valve 24 upstream from T-section coupling 16. Operation of the modified system is similar to that described with reference to FIGs. 1 to 4 except that there is no solenoid valve 19 to block the flow of mains water when hydraulic pump 13 is actuated.

Instead blocking of mains water is performed by the series connection of pressure reducing valve 24 and non-return valve 18. Hydraulic pump 13 is arranged to supply an output pressure that is at least marginally greater than the output pressure associated with pressure reducing valve 24. This gives rise to pressure in T-section coupling 16 that is greater than the mains water pressure downstream of pressure reducing valve 24, preventing flow of mains water whilst hydraulic pump 13 is actuated and is supplying adequate pressure to T-section coupling 16. Dispensing with solenoid valve 19 may provide an advantage in some installations because it may avoid undesirable water hammer which can occur when solenoid valve 19 is switched off rapidly.

FIG. 7 shows an alternative arrangement that is similar to FIG. 6 except that the positions of pressure reducing valve 24 and non-return valve 18 are interchanged.

FIG. 8 shows a wiring diagram associated with the rainwater harvesting system of FIGs. 6 and 7. The latter is identical to FIG. 5 except that solenoid 19 is dispensed with. Operation of the system is also similar to that described with reference to FIG. 5 except that when relay 21 is tripped, it supplies power to pump 13 only causing it to supply water under pressure to T-section coupling 16 that is sufficient to block supply of water from the mains network.

FIG. 9 shows a rainwater harvesting system enclosed in a housing The pump 13 is separate from housing 25 and is connected thereto via water conduit 15. The system is similar to what is shown in the diagram of FIG. 6 and includes an inlet of pressure reducing valve 24 connected to the mains supply via non-return valve 18. The outlet of pressure reducing valve 24 is connected to one terminal of T-section coupling 16. Another terminal of T-section coupling W:provs\DPInnovDivRainwaterHarvesting.doc 16 is connected to the consumer via flow sensor 20. The third terminal of Tsection coupling 16 is connected to pump 13 (not shown) via conduit 15. The system includes a low voltage power supply (transformer) 26 for energizing the controller (not shown). An input from a float level switch mounted in an associated rainwater storage tank (not shown) is connected via conduit 27.

Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention.

W:\pmvrsDPnnovDivRainwatertarvestig.doc

Claims

2. A method of supplementing a mains water supply that is not an air-break supply with rainwater from a rainwater supply, the method including the steps of: providing a pump and a non-return valve in the rainwater supply; providing a normally-open solenoid valve in the mains water supply; detecting demand from a consumer; detecting rainwater in the rainwater supply; and actuating the pump to deliver rainwater via the non-return valve when both consumer demand and at least a minimum amount of rainwater are detected; and actuating the normally-open solenoid valve to close in order to block the supply of mains water when both consumer demand and at least a minimum amount of rainwater are detected, said solenoid valve being held in an open state when no demand is detected.
3. Apparatus for providing a consumer water network with a mains water supply and a rainwater supply, said mains water supply not being an air-break supply, the apparatus including means for detecting a consumer demand, means 11 for detecting the presence of rainwater in the rainwater supply, and means for switching the input of the consumer system from the mains supply to the rainwater Usupply when customer demand and at least a minimum amount of rainwater are detected, the means for switching including a normally-open solenoid valve in the mains water supply, and a pump and non-return valve in the rainwater supply, the solenoid valve being energized to a closed state to block the mains water supply when the pump is activated to supply rainwater and being de-energized to an open state to enable supply of said mains water when demand is no longer detected and Othe pump is no longer activated.
4. An interface unit for connection between a mains water supply, a rainwater supply and a consumer water network, the mains water supply being connected directly to the consumer water network without the use of an air break, the unit including: a mains water conduit for coupling to the mains water supply, the conduit having a normally-open solenoid valve therein; a rainwater conduit for coupling to the rainwater supply, the rainwater conduit having a non-return valve therein; a conduit communicating with the mains water conduit and the rainwater conduit for connection to the consumer water network; and a controller for actuating the solenoid valve and a pump, the interface unit, in use, receiving rainwater from the pump via the non-return valve; wherein, in use, the controller actuates the pump and the solenoid valve so that when consumer demand and the presence of at least a minimum amount of rainwater are detected, the pump is actuated to supply rainwater and the solenoid valve is closed to block the mains water supply, and so that when there is less than a minimum amount of rainwater or there is no demand, said pump is not actuated and said solenoid valve is open to enable supply of mains water.
5. Apparatus for providing a consumer with a mains water supply and a rainwater supply, the mains water supply not being an air-break supply, the apparatus including means for detecting consumer demand and the presence of rainwater in the rainwater supply, and means for switching from the mains water supply to the rainwater supply when consumer demand and the presence of at least a minimum amount of rainwater are detected, the means for switching including a normally open solenoid valve in the mains supply, a pump and non- 12 qn return valve in the rainwater supply and relay means for actuating the solenoid Svalve and pump, wherein when consumer demand and, the presence of at least a minimum amount of rainwater are detected, the pump is actuated to supply rainwater to the consumer via the non-return valve and the solenoid valve is energized to a closed state to block the mains water supply, and wherein when there is no demand, the pump is not actuated and the solenoid valve is not In energized and is in an open state to enable the supply of mains water. DATED: 7 December 2005 PHILLIPS ORMONDE FITZPATRICK Attorneys for: DAVEY PRODUCTS PTY. LTD.