FIELD OF INVENTION

This invention relates to a rainwater harvesting apparatus and more particularly, to an apparatus for harvesting second stage clean rainwater.

DESCRIPTION OF THE PRIOR ART

Rainwater is a natural resource that can be used for any purpose that requires water, for example, landscape use, wildlife and livestock watering, domestic and industrial use, fire protection, and etc.

Rainwater is often harvested by farming communities for irrigation as it is an excellent source of water with no chemicals such as fluoride and chlorine, and no dissolved salts and minerals from the soil. Nowadays, apart from irrigation, rainwater is also harvested for drinking and domestic purposes in many countries of the world. In particular, in arid or semi-arid countries with drought issues, rural areas where water supply system is out of reach, urban areas that have a scarcity of safe drinking water, areas with serious arsenic problem in ground water, states where water supply is unable to meet the needs of a growing population, and etc, rainwater harvesting is a good solution as it provides an alternative and independent water supply.

Rainwater harvesting is a technique where rainwater is collected from various surfaces such as roof tops or other types of manmade above ground hard surfaces, and redirected to a storage tank where it is stored for later use.

A rainwater harvesting system includes basically a catchment area, i.e. a surface from which rainwater can be collected, a storage tank such as a barrel, cistern or water butt for storing the rainwater, and a conveyance setup for channeling the rainwater from the catchment area to the storage tank. The system comes in all shapes and sizes, from a simple system like the water butt to large above and/or underground cisterns with complex filtration systems that can store thousands of litres of rainwater.

In addition to solving the problem of water supply discussed above, rainwater harvesting also positively impacts the environment. For example, in mitigating flooding of low-lying areas, reducing demand on wells which may enable ground water levels to be sustained and hence avoiding ground water depletion, and preventing storm water runoff in sewer systems.

Despite the above advantages, the quality of harvested rainwater has always been an issue especially when rainwater is to be used as drinking water. The quality of rainwater can be affected by air pollution, dead insects, and dirt or organic matter. Moreover, when rainwater is harvested from a catchment surface, the type of construction materials used for the surface may seep chemicals, pesticides and/or other pollutants into the rainwater that can also adversely affect the quality of rainwater.

Also, regular maintenance and cleaning is required to remove sediment, organic particles, bird droppings, leaves, dead insects and other debris that are deposited at the bottom of the storage tank so as to ensure proper operation of a rainwater harvesting system.

Consequently, a first flush diverter is needed to overcome the above disadvantages. The diverter is often installed at the rainwater supply conduit e.g. downpipe to prevent the entry of first flush rainwater, which contains contaminants, into the storage tank, and subsequently to direct second stage clean rainwater into the storage tank.

The first flush diverter extensively in use is a T-shaped diverter comprising an inlet duct connected to a rainwater downpipe for receiving rainwater from the catchment area, an outlet duct connected to a storage tank for conveying clean rainwater to the tank, and a diversion duct connected to a diversion chamber for diverting first flush rainwater into the chamber whereupon first flush rainwater is subsequently drained. A float ball together with its corresponding seat is provided to the joint adjacent the diversion duct for regulating the diversion of incoming rainwater.

The principle of operation is that when the first flush rainwater collected in the diversion chamber via the inlet duct reaches a predetermined level, it causes the ball to float and move towards the seat, which seals off the diversion duct such that further incoming rainwater bypasses the diversion duct and is directed to the inlet duct and is conveyed to the storage tank. Such a first flush diverter system was disclosed in US publication no. 2005/0081926 Al and CN publication no. 1880233 A.

US patent no. 5,407,091 disclosed a first flush diverter employing the same principle of operation described above. The first flush diverter is a tubular pipe housed within a storage tank. The first flush diverter comprises a top opening, a dripper at the bottom, a plurality of holes disposed adjacent the top opening, and a float with its corresponding seating disposed below the holes.

In use, rainwater flows into the diverter via the top opening. As the rainwater fills up the diverter, it causes the float to move upwardly towards the seating and eventually seals off the seating. This prevents further incoming rainwater from entering the diverter and the rainwater passes through the holes into the storage tank.

There are disadvantages to this type of first flush diverter.

When a large amount of rainwater enters the diverter during a heavy downpour, the rapid variation of pressure of incoming rainwater (turbulent flow) affects efficient sealing off of the diversion duct by the float. Thus, first stage contaminated rainwater collected in the diversion chamber slips into the storage tank.

Furthermore, the rainwater collected in the diversion chamber must be retained at a predetermined level all the time during the operation of the first flush diverter. Once the level of rainwater in the diversion chamber drops below the predetermined level, the float leaves its seating and no longer seals off the diversion duct. Thereafter, second stage clean rainwater is not diverted to the storage tank until the rainwater in the diversion chamber increases to the predetermined height again. This results in inefficient collection of second stage clean rainwater as the operation will be disrupted several times in one operational cycle and only a small amount of second stage clean rainwater will be collected in the storage tank especially when rainfall occurs for only a short duration.

Moreover, it is difficult to remove sediment and debris collected in the diversion chamber of existing flush diverters. A user of the first flush diverter system of US publication no. 2005/0081926 Al would need to remove the T-shaped diverter from the diversion chamber before the cleaning process can be carried out, whereas a user of the first flush diverter system of CN publication no. 1880233 A would need to open the lid that is provided at the bottom of the diversion chamber in order to carry out the cleaning process. For a storage tank with a built-in diversion chamber such as US patent no. 5,407,091 where removal of collected sediment and debris in the diversion chamber is unlikely to be possible due to the structure, this will result in accumulation of sediment and debris in the diversion chamber and blockage of the dripper whereupon rainwater collected in the diversion chamber cannot be discharged. This will eventually affect the operation of the first flush diverter.

This invention thus aims to alleviate some or all of the problems of the prior art.

SUMMARY OF INVENTION

In accordance with an aspect of the invention, there is provided a rainwater harvesting apparatus comprising a diversion chamber having an inlet and an outlet. A flow regulator is provided below the inlet and is housed within the diversion chamber. The flow regulator has a unidirectional passageway and a flap is disposed within the passageway. The flap is operatively connected to a float. The outlet is located between the inlet and the flow regulator. In use, first stage contaminant- filled rainwater enters the apparatus via the inlet and fills up the diversion chamber. The rise in the level of first stage rainwater in the diversion chamber causes the float to move upwardly resulting in a corresponding upward movement of the flap which results in closing of the passageway to enable trapping of further incoming second stage clean rainwater within the passageway. The trapped second stage rainwater exerts further pressure on the flap so as to seal off the passageway resulting in diversion of the trapped second stage rainwater toward the outlet for collection. The flow regulator enables the apparatus to automatically collect only second stage clean rainwater.

In an embodiment, the diversion chamber may be an open top chamber. This allows convenient periodical inspection and removal of sediment and debris collected in the diversion chamber without the need to remove any part of the diversion chamber.

The rainwater harvesting apparatus may further comprise a conduit disposed within the diversion chamber to connect the inlet to the outlet. The conduit may have a descending branch and an ascending branch. The descending branch may have the inlet provided at its proximal end and the flow regulator provided at its distal end, and the outlet may be located at the top end of the ascending branch.

In an embodiment, the conduit may further comprise an overflow channel for discharging excess second stage clean rainwater. The overflow channel is fluidically connected to the ascending branch above the outlet.

In another embodiment, the flap may be hemispherical in shape.

In a further embodiment, the flap may be made of polyvinyl chloride (PVC).

In another embodiment, the flap may be made of polyvinyl chloride (PVC) with its top surface lined with hard rubber.

In yet another embodiment, the float may be a ball float.

The passageway may be provided with a top opening and a bottom opening. The top opening allows entry of first stage rainwater into the diversion chamber. The flap and float is operatively connected through the bottom opening of the passageway with the flap located within the passageway and the float located outside of the passageway.

According to an embodiment, the diameter of the flap may be greater than the diameter of the top opening.

According to an embodiment, the diameter of the float may be greater than the diameter of the bottom opening.

In an embodiment, the diameter of the top opening may be equivalent to the diameter of the descending branch of the conduit.

In an embodiment, the diameter of the top opening may be greater than the diameter of the descending branch of the conduit.

In yet another embodiment, the descending branch of the conduit may further comprise an orifice for allowing slow release of trapped water at the distal end of the descending branch.

The diversion chamber may further comprise a discharge means for draining rainwater collected therein.

The diversion chamber may be further provided with an overflow weir. The height of the overflow weir may be substantially higher than the position of the float when the flap has closed off the top opening of the passageway.

According to an embodiment, the apparatus may further comprise a collection tank within which the diversion chamber is housed, and the outlet is disposed to flow second stage rainwater into the collection tank.

The present invention seeks to overcome the problems of the prior art by providing a rainwater harvesting apparatus that automatically prevents the entry of first stage contaminant-filled rainwater collected in the diversion chamber into the collection/storage tank. This is achieved by the position of the flow regulator which is well above the maximum level of rainwater collected in the diversion chamber.

Furthermore, the present invention also enables the creation of a highly efficient seal. The passageway is closed-off when the flap is lifted upwardly resulting from the corresponding upward movement of the float. As the rainwater continues to flow into the apparatus, due to the configuration of the flow regulator and the relative vertical positioning of the inlet and outlet in relation to the flow regulator, the pressure exerted by the incoming rainwater on the flap results in the sealing off of the passageway. This allows pressure built up within the passageway which forces the rainwater trapped within to flow toward the collection/storage tank via the outlet. This is achieved automatically without the aid of mechanical parts or manual intervention.

In addition to the above advantages, the apparatus retains all the advantages of the prior art, while remaining simple and inexpensive in construction.

All advantages achieved by the present invention are as hereinafter described.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated, although not limited, by the following description of embodiments made with reference to the accompanying drawings in which:

Figure 1 shows a perspective view of a rainwater harvesting apparatus of the present invention.

Figure 2 is an enlarged view of the conduit of the apparatus of Figure 1.

Figure 3(a) shows a side view of the flow regulator of the apparatus of Figure 1 when the flap has not sealed off the top opening of the passageway. Figure 3(b) shows a side view of the flow regulator of the apparatus of Figure 1 when the flap has sealed off the top opening of the passageway.

Figure 4 shows a perspective view of the discharge means of the apparatus of Figure 1.

Figure 5 shows a cross-sectional view of the discharge means of Figure 4. DETAILED DESCIRPTION OF THE EMBODIMENTS

The present invention relates to a rainwater apparatus for automatically collecting only second stage clean rainwater and prevents entry of first stage contaminant- filled rainwater into a collection tank. The apparatus 10 mainly comprises a diversion chamber 20 having an inlet 21 and an outlet 22, and a flow regulator 23 provided below the inlet 21 and housed within the diversion chamber 20. The outlet 22 is located between the inlet 21 and the flow regulator 23.

As seen in the embodiment of Figure 1, the apparatus 10 may further comprise a collection tank 30 within which the diversion chamber 20 is housed. The collection tank 30 is connected to the diversion chamber via the outlet 22. In an alternative embodiment, the collection tank may be provided with an outlet 301 which connects to a separately provided storage tank. Alternatively, the apparatus 10 may be connected to a separately provided storage tank via the outlet 22.

The diversion chamber 20 is a chamber of any suitable shape and size. For example, the chamber may have a cylindrical or cuboidal shape. The diversion chamber 20 seen in Figure 1 is cylindrical in shape, and is preferably provided in an open top configuration. This allow for convenient periodical inspection and removal of sediment and debris collected in the diversion chamber 20 without the need to remove any part of the diversion chamber 20. Any suitable material such as polyvinyl chloride (PVC) or fiberglass may be used in the manufacture of the diversion chamber 20. The inlet 21 and outlet 22 are provided for entry of rainwater into the diversion chamber 20 and for exit of second stage rainwater, respectively. Both or either of the inlet 21 and outlet 22 may be simple openings disposed at the top or side wall of the diversion chamber 20. The inlet 21 may be connected to a rainwater downpipe.

A conduit 24 is disposed within the diversion chamber 20 to connect the inlet 21 to the outlet 22, enabling the flow of second stage rainwater from the inlet 21 to the outlet 22 for collection.

The conduit 24 comprises a descending branch 241 with its proximal end being disposed to connect to the inlet for conveying incoming rainwater downwardly, and its distal end associated with the flow regulator 23 as hereinafter described. The descending branch 241 may be disposed vertically or at an incline. The conduit 24 further comprises an ascending branch 242 connected at its top end to the outlet 22 and at its bottom end to the descending branch 241. The ascending branch 242 may be disposed vertically or at an incline. The conduit is substantially U-shaped with the joint between the ascending and descending branches of the conduit located above the flow regulator 23.

Optionally, the distal end may be provided with an orifice 27 that allows for emptying of the conduit descending branch 241 and the passageway 236 when rainfall stops.

The conduit may also optionally comprise an overflow channel 243 for discharging excess second stage rainwater when the collection and/or storage tank is full. The overflow channel 243 may be disposed in any suitable manner such that it is connected to the top of the ascending branch 242, at a position above the outlet 22. In the embodiment shown in Figure 1, the overflow channel 243 is vertically disposed parallel to the ascending branch 242 such that the channel forms an inverted U-shape with the ascending branch 242. The joint between the ascending branch 242 and overflow channel 243 is located above the outlet 22. With reference to Figure 2, when the apparatus 10 is filled and the rainwater collected in the collection tank 30 reaches a predetermined level LI, further incoming second stage rainwater through the descending branch 241 is forced to move upward to L2 in the ascending branch thereby overflowing the top of the ascending branch and subsequently flowing downwardly through the overflow channel 243 into the diversion chamber 20.

In another embodiment, the overflow channel 243 may also be disposed to extend from the collection tank 30 into the diversion chamber 20 such that excess second stage rainwater can be discharged directly from the collection tank 30 into the diversion chamber 20. In this embodiment, the overflow channel 243 is disposed at the same level as the outlet 22.

The conduit 24 may be of varying lengths and diameters to suit the size of the diversion chamber 20 or the size of a downpipe/catchment area from which rainwater flows. It may be mounted to the diversion chamber by any suitable means, for example, by way of brackets. Any suitable material such as plastic, PVC, fiberglass or the like may be used in the manufacture of the conduit 24.

As mentioned above, the flow regulator 23 may be disposed at the distal end of the conduit descending branch 241 for regulating incoming rainwater that enters the apparatus 10. The flow regulator 23 comprises a unidirectional passageway 236 of any suitable shape and size. In the embodiment seen in Figure 1, the passageway 236 is cylindrical with a top opening 231 and a bottom opening 232 (not shown). With reference to Figures 3(a) and 3(b), the distal end of the conduit descending branch 241 fluidically connects to the side of the passageway 236 to enable flow of rainwater from the descending branch 241 into the passageway 236. The diameter of the top opening is preferably equivalent to or greater than the diameter of the descending branch of the conduit.

The flow regulator 23 is further provided with a flap 233 and a float 234. The flap 233 is disposed within the passageway 236 and may be of any suitable shape that enables sealing of the top opening 231, whereas the float 234 is disposed outside the passageway 236 and may be of any suitable shape. For example, as shown in Figures 3(a) and 3(b), the flap 233 may be hemispherical in shape and resemble a mushroom cap and the float 234 may be a ball float.

The flap 233 is operatively connected to the float 234 through the bottom opening 232 of the passageway 236 by any suitable connecting member 235 such as a rod, or a rigid cable. The length of the connecting member 235 is preferably substantially greater than the length of the passageway 236.

The diameter of the flap 233 is preferably greater than the diameter of the top opening 231 of the passageway 236, and the diameter of the float 234 is preferably greater than the diameter of the bottom opening 232. The diameter of the bottom opening 232 should be just sufficient to allow free vertical movement of the connecting member so as to minimize leakage of rainwater trapped within the passageway 236.

Any material that allows for a highly efficient sealing off of the top opening 231 of the passageway 236 may be used in the manufacture of the flap 233, for example, plastic, silicon or the like. Preferably, the flap 233 is made of PVC, or more preferably, is made of PVC with its top surface lined with hard rubber. Any suitable light buoyant material may be used in the manufacture of the float 234.

As mentioned above, an orifice 27 may be disposed at the distal end of the conduit descending branch 241 adjacent the flow regulator 23. When rain has stopped, the orifice 27 allows for emptying of the conduit descending branch 241 and passageway 236 so as to automatically reset the apparatus 10 for next use. The diameter of the orifice 27 must be small such that the emptying rate will not affect the water pressure within the conduit 24 needed for the working of the apparatus 10. Thus, the diameter of the orifice 27 is dependent on the size (diameter) of the conduit 24, for example ranging from about 3 mm to about 12 mm for a conduit ranging from about 75 mm to about 300 mm, respectively.

A discharge means 25 may be further provided to the diversion chamber 20 for discharging first stage rainwater collected. The discharge means 25 may be of any suitable configuration such as a simple opening disposed at the bottom of the diversion chamber 20 or adjacent the bottom of the chamber side wall. The size of the opening depends on the desired discharge rate which will in turn affect the collecting rate of rainwater within the diversion chamber 20. The discharge means 25 may be adjustable in size as shown in Figure 4. In this embodiment, the discharge means 25 comprises a discharge hole 251 and a vertically adjustable panel 252 for regulating the size of the opening of the discharge hole 251. The adjustable panel 252 may be slidably mounted at the inner or outer surface of the side wall of the diversion chamber 20. Apart from the adjustable panel, any other manner of adjusting the size of the discharge hole 251 may be employed. A tapered trench may be further provided to the discharge means 25, to facilitate flow of the discharging rainwater.

An overflow member may be further provided to the apparatus 10 to prevent overflow of the diversion chamber 20. The overflow member may be of any suitable configuration such as a simple aperture disposed on the wall of the diversion chamber at a predetermined height. In the embodiment of Figures 4 and 5, the overflow member comprises an overflow weir 26 provided on the side wall adjacent the bottom of the diversion chamber 20, and the discharge means 25 is operatively associated with the weir 26. The weir 26 comprises an upright barrier that forms an open top spillway with the discharge hole 251 disposed at the lower end of the barrier and the adjustable panel 252 slidably mounted to the barrier. Rainwater that rises higher than the height of the barrier, L3, is discharged via the spillway. Position L3 is substantially higher than the position of the float 234 when the flap 233 has closed-off the top opening 231 of the passageway 236, when the apparatus 10 is in use.

In use, rainwater collected from the catchment surface enters the apparatus 10 via the inlet 21, and subsequently flows downwardly through the descending branch 241 of the conduit 24. As this first stage contaminant-filled rainwater reaches the distal end of the descending branch 241, it flows through the passageway 236 of the flow regulator 23 and enters the diversion chamber 20 via the top opening 231 of the flow regulator 23. The rainwater collected in the diversion chamber 20 is discharged out of the apparatus 10 via the discharge hole 251 adjacent the bottom of the chamber side wall. The discharge rate of the first stage rainwater is regulated by the opening size of the discharge hole 251 which is pre-adjusted such that the discharge rate is slower than the collecting rate of rainwater in the diversion chamber 20, thereby enabling rising of the level of water in the diversion chamber 20. The pre-adjusted opening size of the discharge hole 251 also functions to determine the volume of first stage contaminant-filled rainwater to be discharged before second stage clean rainwater is collected.

As the volume of first stage rainwater in the diversion chamber 20 continues to increase, it causes the float 234 to rise resulting in a corresponding upward movement of the flap 233. Once the rainwater in the diversion chamber 20 reaches a predetermined level, namely, no higher than L3, the flap 233 is lifted to its maximum height where it shuts off the top opening 231 of the passageway 236. At this time, rainwater from the conduit descending branch 241 is not able to enter the diversion chamber 20.

In addition to the buoyant force from the float 234, further incoming rainwater trapped within the passageway 236 exerts further pressure on the flap 233. This enables the formation of a tight seal by the flap 233 against the top opening 231, and results in water pressure being built up within the conduit descending branch 241.

As the water pressure within the conduit descending branch 241 increases, the pressure forces the second stage rainwater in the descending branch 241 upwardly through the ascending branch 242 where it is conveyed to the collection and/or storage tank via the outlet 22.

The volume of rainwater collected in the diversion chamber 20 reaches its maximum level when the water level reaches the predetermined height L3, whereas the volume of second stage rainwater collected in the collection tank 30 in the embodiment as shown in Figure 1 reaches its maximum level when the water level reaches the predetermined height of LI, i.e. the height of the outlet 22. This is the point where the collection tank 30 is considered full. Excess incoming second stage rainwater moves further upward to the predetermined height of L2 of the conduit ascending branch 242 whereby it overflows downwardly into the diversion chamber 20 via the overflow channel 243.

Due to the configuration and position of the flow regulator 23 relative to the inlet and outlet as described in the earlier paragraphs, collection of second stage rainwater in the collection/storage tank continues even when the volume of first stage rainwater in the diversion chamber 20 starts to decrease by the fact it is being slowly discharged via the discharge means 25. This is because the water contained within the conduit descending branch 241 continues to exert pressure on the flap 233. Therefore, a decrease of volume in the diversion chamber 20 will not affect the collection of second stage rainwater.

In such a way, second stage rainwater is collected automatically and continuously without interruption and without the aid of mechanical parts or any manual intervention.

Collection of second stage rainwater in the collection/storage tank continues until the rainfall stops. However, if rainfall does not stop after the collection/storage tank is full, the second stage rainwater in the conduit ascending branch 242 is forced further upward and discharged through the overflow channel 243 into the diversion chamber 20. When the excess second stage rainwater contained in the diversion chamber 20 increases beyond the predetermined height L3 of the overflow member, the rainwater is discharged through the overflow member 26. Advantageously, excess second stage clean rainwater that overflows into the diversion chamber provides an in-built automatic cleaning system to the apparatus of the present invention where sediment and debris collected therein are flushed away along with the second stage rainwater.

When rainfall stops, the rainwater trapped within the conduit descending branch 241 and the passageway 236 drains slowly through the orifice 27 into the diversion chamber 20. Once the passageway 236 is emptied, the flap moves downwardly to its descended position (Figure 3(a)) and the apparatus 10 is now considered reset automatically and is ready for the next rainwater collection.

All directional statements such as proximal, distal, top, bottom, upward, downward, above, below, made herein are relative to the orientation of the apparatus, in use.

As will be readily apparent to those skilled in the art, the present invention may easily be produced in other specific forms without departing from its scope or essential characteristics. The present embodiments are, therefore, to be considered as merely illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within therefore intended to be embraced therein.