GB2503690A

GB2503690A - A rainwater agitation apparatus

Info

Publication number: GB2503690A
Application number: GB1211860.0A
Authority: GB
Inventors: Stephen Bannocks
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-07-04
Filing date: 2012-07-04
Publication date: 2014-01-08
Anticipated expiration: 2032-07-04
Also published as: GB201211860D0; GB2503690B

Abstract

A water agitation 400 apparatus for use with rainwater storage tanks comprising a paddle 435 for agitating the water contained within a rainwater storage tank 405 and drive means 455, 465, 460 configured to impart motion to the paddle in response to an environmental condition. The environmental conditions may be rain, wind or sunlight. Ideally, the paddles 435 are connected to a sleeve 425 with an internal thread which engages with the threads of a vertical axle 440 that is rotated by the drive means. The apparatus may further comprises a float 410 and collar 415 which impart motion, via the sleeve 425, to the paddle in response to a change in water level within the storage tank. The drive means may comprise a wind turbine or a photovoltaic cell coupled to an electric motor. The apparatus is used to reduce and/or prevent bacteria, algae or sediment build-up.

Description

WATER AGITATION APPARATUS

The present invention relates generally to the field of rainwater storage tanks, and in particular, although not exclusively, to water storage tanks for storing rainwater collected from buildings for re-use and! or recycling.

Rainwater storage tanks are known in the art. Such tanks allow rainwater to be stored for subsequent use around the home, such as for the flushing of lavatories and watering garden plants, amongst other uses.

At high temperatures (for instance, in cxcess of 55 degrees centigrade) algae, biofllm, bacterial and anaerobic organism growth can occur within the storage tank.

Even at temperatures lower than this, substantial build-up of such organism growth may occur over time. In addition, sediment may he washed into the rainwater storage tank during use. This sediment settles out of suspension in the water and collects at the bottom of the rainwater storage tank. Furthermore, water inside such a storage tank 1 5 may become stagnant.

Accordingly, it becomes necessary for rainwater storage tanks to he cleaned periodically. This can be particularly difficult in situations in which such rainwater storage tanks are inaccessible, such as where the tanks are located oil art external wall of a building, substantially above ground level. It is apparent that there is a need to reduce the amount of cleaning that is required of rainwatcr storage tanks.

According to a first aspect of the present invention, thcre is provided a water agitation apparatus for use with rainwater storage tanks, comprising: a paddle, for agitating water contained within a rainwater storage tank; and drive means configured to impart motion to the paddle in response to an environmental condition.

In this way, bacteria and/or algae tnay be prevented from joining/clinging together to form hiofilms and/or mating. Agitation of water disrupts conglomerations anti/or clusters of bacteria anti/or algae, thereby preventing them from tnating anti/or reproducing. Furthermore, varying pressure is undesirable for bacterial growth. In addition, by agitating water contained within a rainwater storage tatik, oxygen may be introduced into the water such that the growth of anaerohic bacteria may be inhibited.

Therefore in some embodiments, die invention may he a water aeration apparatus.

Furthermore, sediment may he prevented from falling out of suspension in die water, and may instead he removed with the water when extracted for use. The sediment

I

therefore does not need removal from a rainwater storage tank in a separate cleaning process. In addition, the sediment cannot act as a nutrient or as nudeacion points f*r algae of bacterial growth.

Tn this way, water contained within a rainwater storage tank may he prevented from going stagnant. Collection of sediment within a rainwater storage tank may he reduced, as may growth of algae and/or anaerobic bacteria. Furthermore, the operation of the apparatus may be entirely automatic. The amount of cleaning of a rainwater storage tank may therefore be reduced.

The water agitation apparatus may be, for instance, a water stirrer or a water agitator. The minwater storage tank may be a domestic rainwater storage tank.

Agitating water may comprise mixing, stirring and/or creating turbuknt movement.

The motion to the paddle may he reciprocating motion and/or rotational motion. The paddle may he a propeller, a propeller blade, a hat and/or a turbrne. The environmental condition may he rain and/or wind and/or sunlight.

The drive means may comprise a float configured to he disposed on the surface of water within a rainwater storage tank. The drive means may comprise a transmission coupling configured to impart motion to the paddk in response to a change in water level of water within a rainwater storage tank.

Tn this way, water contained within a rainwater storage tank may be agitated in response to both rain when the water level rises) and extraction of water from the rainwater storage tank (xvhen the water level lowers).

The transmission coupling may comprise a threaded axk configured to he disposed with its axial length substantially vertical xvithin a rainxvater storage tank. The transmission coupling may comprise a sleeve having an internally threaded bore for receiving the threaded axle therein, and for cooperating therewith. Movement of the float in a vertical direction may induce longitudinal and rotational movement of the sleeve relative to the threaded axle, such that motion may he imparted to the paddle for agitating water contained within a rainwater storage tank. The threaded axie may be a helical screw. The transmission coupling may comprise an Archimedes screw.

In particular, movement of the iloat in a vertical direction, which may be considered as longitudinal movement, may induce longitudinal movement of the sieeve rdative to the threaded axle along the axial length of the threaded axie, and thus rotational movement of the sleeve relative to the threaded axle about the axial length of the threaded axle, such that motion may be imparted to the paddle for agitating water contained witinn a rai water storage tank.

The paddle may he substantially fixedly connected to the sleeve. The sleeve may he substantially rotatably connected to the float.

The threaded axle may he substantially fixedly connectable to a rainwater storage tank. In particuhw, in one embodiment, the paddle may be substantially fixedly connected to the sleeve and the sleeve may be substantially rotatably connected to the float; the threaded axle may he substantially fixedly connectable to a rainwater storage tank. In another embodiment, the paddle may be substantially fixedly connected to the lO skreve and the threaded axle may be substantially fixedly connected to the float; the skreve may be substantially rotatably connectable to a rainwater storage tank. In a further embodiment, the paddle may he substantially fixedly connected to the threaded axk and the threaded axle may be substantially rotatably connected to the float; the sleeve may he substantially fixedly connectable to a rainwater storage tank. In a still further embodiment, the paddle may be substantially fixedly connected to the threaded axle and the sleeve may be substantially fixedly connected to the float; the threaded axle may be substantially rotatably connectable to a rainwater storage tank. Reference to X being substantially rotatahly connected to Y riay iii sortie errihodirnerits include X being substantially rotatably connected to Y, hut being substantially restrained from longitudinal and/or lateral movement relative to Y. Reference to X being substantially fixedly and/or rigidly connected to Y may in some embodiments include X being held in a fixed orientation with respect to Y and being substantially resuained from longitudinal and/or ateral movement rebtive to Y, hut may still allow for small amounts of relative movenmnt between X and Y such that desired operation is not affected.

The float may be held in a fixed orientation with respect to the rainwater storage tank; that is, the float may he preventetl from rotating with respect to the rainwater storage tank. Nevertheless, the float may be permitted to move in a longitudinal and/or lateral sense relative to the rainwater storage tank.

The float may he arranged to prevent sunlight from reaching the water. In this way, algae growth can he prevented. The float may also prevent formation of a hioflirn on the surface of the water.

The float may comprise a weighted insert disposed therein, such that pressure exerted by the float on the water is increased. In tins way, water exftactiou from the tank may he improved. Akeruativdy ot additlinally, the weighted insert may enahie more smooth movement of the float with the transmission coupling, for instance by enabling positive engagement of the respective The weighteJ insert may he a leaJ insert, or any other suitably dense material.

The drive means may comprise a turbine and a transmission mechanism coupled between the turbine anJ the paJJle. The turbine may comprise a winj turbine. The wind turbine may be a vertical axis wind turbine such as a Savonius or Darrieus wind turbine, although other verfical axis wind turbines known to those skilled in the art arc contemplated. Alternatively, the wind turbine may be a hori2ontal axis wind turbine.

The turhine may comprise a water turbine configured to he powered by rainwater conveyed through a rathwater downpipe. For instance, the water turbine may he a reaction water turbine, an impulse water turbine or an Architnejes screw.

Alternatively, the water turbine may be an utulershot, hreastshot or overshot water wheel. Ijowever, other forms of water turbines are contemplateJ.

The transmission mechanism may have a gear ratio of between 1:1 and 100:1, for instance between 10:1 aniJ 80:1, aniJ iii 50:1. In this way, the fi uRis inciJent on the turbine which have a relatively high velocity and relatively low mass may be used to agitate a large volume of water in the raffiwater storage tank.

The drive means may comprise a photovoltaic cell coupled to an electric motor.

Any combination of the various forms of drive means may be incorporated into a single water agitation apparatus in order to make hest use of the variety of prevailing environmental conditions.

AccorJing to a second aspect of the pru invention, there is proviJed a rainwater storage tank md uJing any one or tnore emboJiments of the first aspect.

AccorJing to a third aspect of the pru invention, there is provi(Ied a methoJ of agitattng water contained within a rainwater storage tank, comprising: providing any one or more embodiments of the first aspect; and agitating water within the rainwater storago tank in response to an environmental condidon.

The ahove and other charactcristics, foatures and advantages of the present invention will become apparent from the following detailed description, taken in Conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings: figure 1 is a cross section of the apparatus according to a first embodiment of the present invention, installed in a rainwater storage tank; figure 2 is a pe pective view of a rainwater storage tank that includes the apparatus shown in figure 1 therein; and Figure 3 is a perspective view of the rainwater storage tank of figure 2 with its outer easing removed.

lO The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the si2e of some of the elements may he exaggerated and not drawn to scale for ill ustrative puoses. The dimensions and the relative dimensions (10 not correspond to actual reductions to practice of the invention.

Furthennore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for (leserihirig a sequence, either temporally, spatially, in ranking or ii any other manner. It is to he understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to he understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to he noticed that the term "comprising", used in the claims, should not he interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, hut does not preclude the presence or addith)n of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and 13" should not he limited to devices consisting only of components \ and B. It means that with respect to the present invention, the onlY relevant components of the device are A and 13.

Similarly, it is to he noticed that the term "connected", used in the description, should not he interpreted as being restricted to direct connections only. Thus, the scope of the expression "a device A connected to a device B" should not he limited to devices or systems wherein an output of device A is direcfly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may he a path including other devices or means. "Connected" may mean that two or more elements are either in direct physical or electrical contact, or that two or lO more elements are not in chrect contact with each other but yet still co-operate or interact with each other.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the presett invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may refer to different embodiments.

Furthermore, the particular features, structures or characteristics of any etuhodinierit or aspect of the invention may he combined in any suitable manner, as would he apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as witH he understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any cornhinatton.

Tn the descnpnon provided herein, numerous specific details are set forth.

Tjowever, it is understood that embodiments of the invention may he practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of

this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lo\ver limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to he construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term "at least one" may, in some embodiments, mean only one.

The invention will now be described by a detailed description of several ernhodinierits of the invention. It is clear that other ernhodiiiients of the invention can he configured according to the knowledge of persons skilled in the art without departing from the true spirit or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

Figure 1 is a cross section of the apparatus 400 according to a first embodiment of the present invention, installed in a rainwater storage tank 405 having a height of approximately 80cm, and a width and depth of approximately 22cm each. The apparatus 400 comprises a float 410, that is configured to fit inside the rainwater storage tank 405 and substantially cover the surface of the water 415 inside the tank 405. The float 410 comprises polystyrene, hut may he made from any other buoyant material, for example a closed-cell foam. The float 410 further comprises a weighted insert 420, shown in the figure as located on an upper surface of the float; however, other locations, such as embedded within the float, or distributed throughout the float are also envisaged. The weighted insert 420 serves to increase the downward pressure of the float 410 on the surface of the water 415. The float comprises a central hole passing therethrough from an upper side to a lower side of approximately 2cm in diameter.

A sleeve 4-25 is mounted on the float 410 by means of a collar 430. The sleeve 425 comprises a tubular portion having an threaded axial hurt and an annular sleeve llange having a cenflal hole aligned with the axial hurt at one end thereoL The axial hove is aligned with the central hole of the float 410. The annular sleeve flange sits inside the collar 430, which comprises two annular plates, each having a respective central hole aligned with the axial bore of the sleeve 425, the annular plates connected together by a wall around their outer peripheries. The sleeve 425 is prevented from longitudinal motion in relation to the float 410 by the collar 430, hut is substantially free to rotate in the collar 430. Rigidly connected to the sleeve 425 arc two paddIes 435 of lO trapc2oidal shape. The paddles 435 may be of any other suitable shape, such as rectangular, triangular, circular, etc. In alternative embodiments, there may be three, four, live, six, or any other number of paddles 435 rigidly connected to the sleeve 425.

The paddles 435 extend from the sleeve to substantially the entire width of the rainwater storage tank 405.

Passing through the central hole of the float 410, and the axial bore of the sleeve 425 is a vertically disposed externally threaded axle 440 that is coupled at a lower axial end to the lower interior surface of the water storage tank 405. The threaded axle 440 is approxittiately 80cm iii length, anti has a diameter of approxirtiately 2cmn. The external thread of the axle 440 cooperatively engages with the internal thread of the tubular portion of the sleeve 425 such that longitudinal motion of the sleeve 425 along the axle 440 causes rotation of the sleeve 4-25 about the axle 440, thereby causing rotation of the paddles 435 in the water 415. In particular, a change in the level of the surface of the water 415, due to, for instance, an increase in water 415 in the water storage tank 405 due to rainfall, or a decrease in the water 415 in the water storage tank 405 due to extraction by a user, will cause the float 410 to rise or fall within the water storage tank 405, leading to a corresponding longitudinal motion of the sleeve 425 along the axle 440 and thus rotation of the paddles 435.

A separate and distinct arrangement for agitating the water 415 is also present in the apparatus 400. The axle 440 is additionally hollow having an elongate rod 44-5 passing therethrough, the rod 445 being free to rotate therein, and being coupled to the lower interior surface of the water storage tank 405, such that lateral movement is inhibited, hut rotational movement is permitted, \vith respect to the \vater storage tank 405. Adjacent a lower end of the rod 445 are rigidly connected two auxiliary paddles 450 of substantially triangular form, extending from the rod 445 to the periphery of the water storage tank 405. In other embodiments, a different number of auxiliary paddles 450 may be present, as with the paddles 435 discussed above. Rotation of the rod 445 causes rotation of the auxiliary paddles 450 about the rod 445.

Rigidly coupled to an upper end of the rod 445 is a wind turbine 455. The wind turbine shown in the figures is a four-cup vertical-axis wind turbine of the drag type.

The cups used in the wind turbine 455 are hollow hemispherical cups held at a predetermined distance from a rotational axis of the wind turbine by respective arms.

(I)ther wind turbines are envisaged, such as the Savonius wind turbine. In addition, lO instead of rigid coupling to the rod 445, the wind turbine 455 may be coupled via a gearing system in order to most effectively use the torque generated by the \vind turbine 455. In some variations, the rod 445 rotates inside the axle 440 on hearings. However, in this embodiment, the rod 445 rotates inside the axle 440, lubricated by the water 413 inside the water storage tank 405.

Disposed on an upper end of the axle 440 is an annular axle flange 460, having a central hole aligned with the axle 440. The thickness of the annular axle flange 460 varies across a diameter thereof, such that a lower surface of the annular axle flange 460 lies in a horizontal platte, arid an upper surface of the at trwl ar axle flange 460 lies in a platre inclined at an angle of approximately 5 to the horizontal. Other angles are considered. Disposed around the rod 445, and rigidly fixed thereto, is a rod flange 465.

The rod flange 465 rests on the annular axle flange 460. The thickness of the rod flange 465 varies across a diameter thereof, such that an upper surface of the rod flange 463 lies in a horizontal plane, and a lower surface of the rod flange 465 lies in a plane inclined at an angle of approximately 50 to the horizontal. Other angles are considered.

In particular, in some embodiments, the thickness of only one of the annular axle flange 460 and the rod flange 465 varies across a diameter thereof. In this way, rotation of the rod 445 inside the axle 440 causes relative longitudinal movement of the axle 440 and rod 443, which serves to apply varying downward pressure to agitate components of the apparatus that are in the water, such as the paddles 435 and the auxiliary paddles 450 thus further dismpting aerobic bacteria.

The relative amounts of friction and/or resistance to movement hetxveen die rod 445 and the axle 440, and between the axle 440 and die sleeve 425, is chosen in this arrangement to permit independent rotation of the paddles 435 and auxiliary paddles 450. For instance, thc amount of rcsistance to movement between the rod 445 and the axle 440 may he equal to the anaount of resistance to mwement between the axle 440 and the sleeve 425. Alternatively, the amount of resistance to movement between the rod 445 and the axle 440 may he substantially less than the amount of resistance to movement between the axle 440 and the sleeve 425, for instance, a ratio of 1:2, 1:3 or 1:10, or at any point between. As a further alternative, the amount of resistance to movement between the rod 445 and the axle 440 may be substantially more than the amount of resistance to movement between the axle 440 and the sleeve 425, for instance, a ratio of2:1, 3:1 or 10:1, or at any point between.

lO Substantially the entire apparatus 400 may be made from a plastics material.

Figure 2 is a perspective view of a water storage tank 50, suitable for having the apparatus of figure 1 installed therein. The storage tank 50 comprises an outer casing 120. Outer casing is substantially cuhoidal in form, having a vertical height of approximately 100cm, a horh<ontal width of approximately 70cm and a horizontal depth of approximately 22cm. A recess t 30 having a substantially uniform depth of approximately 1cm is formed in a front face of the outer casing 120, approximately 5cm from each edge of the front face. A further recess 135 is located ha one corner of the recess 130.

A water inlet!40 is located at a point centrally located in a top surface of the outer casing 120, for providing fluid communication between an incoming rainwater downpipe and the interior of the outer casing 120. The water inlet 140 comprises a square opening of side length approximately 22cm. The water inlet 140 is sized to he suitable for receiving water from an incoming rainwater downpipe. The water inlet 140 includes a sieve 500 that slopes at an angle of approximately 45° from a rear edge of the water inlet 140, and is arranged to allow the passage of water therethrough, hut prevent entry of unwanted material such as twigs, dead leaves or detritus into the water storage tank.

The outer casing 120 is also provided with two small recesses 150 on each side, suitable for aligning screw fixings in order for the outer casing 120 to be secured to the tank body (not shown).

The outer casing 120 is moulded from plastics material having a thickness of hetween approximately 3mm and approximately 8mm, and in particular approximately 6mm. In alternative embodiments, the outer casing 120 includes insulated walls and/or a reflective outer covering. In particular embodiments, the colour and/or texture of the outer casing 120 may he chosen to match the surrounding environment, such as brick/stone work, wood and/or other building materials.

Around an upper portion of the outer casing 120 are provided vents 510 that allow flow of air into the interior of the outer 120 casing such that wind may he incident on the wind turbine 455 (not shown). In alternative embodiments, the wind turbine 4-55 is disposed outside the outer casing 120 such that incident air-dow may be uninhibited.

Figure 3 corresponds to the same view as figure 2, with the outer casing -! 20 removed. A tank body 160 has substantially six faces, and resides within the outer casing 120. A front face of the tank bcxiy is substantially rectangular, having a height of approximately 80cm and a width of approximately 65cm. A back face of the tank body is also substantially rectangular, having a height of approximately 80cm and a width of approximately 65cm. The hack face also comprises a flange 170 around a portion of its periphery that extends across the top of the back face, and clown each side perip1ery to 25cm short of the bottom of the hack face. In an alternative emboditnent, the flange extends around the entire periphery of the hack face. The flange 170 has a width of Scm at the sides and 25cm at the top. The side faces are rectangular having dimensions of approxitriately 80cm by approxirriately 22cmri. A bottom face is substantially rectangular and has a length of approximately 65cm and a width of approximately 22cm.

A top face is substantially rectangular, and seals the tank body 160. The tank body 160 may be made from a plastic material. The tank body 160 may be substantially opaque.

In particular, the tank body 160 may he black. In this way, light ftansfer to the interior of the tank body 160 may he ntinimised, in order to lintit photosynthesis and algae owth.

The flange 170 has 19 pilot holes 180 of diameter approximately 0.5mm spaced at intervals of approximately 10cm, although other numbers of pilot holes and spacing would he apparent to one skilled in the art. The pilot holes may he used to secure the tank body to a wall with fixing means, such as screws.

A recesses portion 190 of the tank body 160 is provided around a lower portion of the tank body 160, such that the tank body 160 may rest in a close fit within a wall-mounted bracket (not shown).

Within the tank body 160 are two stiffening ribs 210 that extcnd betwcen, and provide mutual support to, the front and hack faces, which is particularly important when the tank body contains xvater.

A bypass downpipe 220 is provided within the tank body 120 and has a semi-circular cross-section. ljowever, a bypass downpipe having a rectangular cross-section is also considered as appropriate as an alternative embodiment. The bypass do\vnpipe 220 comprises a vertical section orientated with its axial bore vertical. The vertical section is defined by the front face of the tank body 160 on one side, and a vertical wall 230, of convex shape, on an opposing side. Thc vertical wall 230 extends from the front face into the interior of the tank body 160.

The tank body 160, stiffening ribs 210 and bypass downpipe wall 230 are moulded from plastics material having a thickness of between approximately 3mm and approximately 3mm, and in particular 6mm. The tank body may be insulated, either by removable insulation members, or by the outer casing 120.

A tank body recess (not shown) having a substantially uniform depth of between approximately 0.5cm and 1cm may optionally he formed in the hack face of the tank body 160, approximately 5cm from each cdge of the back face. In use, foam may be placed into the tank body recess, which may act to insulate the tank body 160 from a wall of a building to which it is connected. For instance, the foam may he injected into the tank body recess via one or more injection holes that each form a passage from the sides of the tank body into the tank body recess, for instance from a nozzle of an aerosol foam gun. Optionally, expanding foam may he used, which may provide an adhesive effect in securing the tank body to a wall of a building. In this case, the expanding foam may provide sufficient adhesion to secure an empty tank body to the wall in order for additional fixing means to he used to secure the tank body petmanetitly to the wall. Optionally or additionally, the expanding foam may provide sufficient adhesion to distribute the weight of a filled tank body across a larger surface area, so as to improve the securing effect. In any case, the foam may provide adhesion to an uneven wall surface, a wall of varying structural rigidity, flaky render, mortar or another wall surface. Optionally or additionally, the expanding foam may provide a reinforcing or stiffening effect which helps distribute the weight of a full tank body between alternative fixing means.

Within the tank body 160, the two stiffening ribs 210 substantially split the interior of the tank body into three independent water storage tanks 405. In some embodiments, the stiffening ribs 210 may only partially separate the independent water storage tanks 405, and water may be allowed to move between the water storage tanks 4Q5 \çTjfr1 each of the three water storage tanks is disposed an apparatus 400. The float 410, weighted insert 420 and axle 440 can be seen in each water storage tank 405.

The apparatus 400 located in the centre water storage tank 405 is not equipped with a wind turbine 455 due to lack of space. In altenntive embodiments, a water wheel may be floated on the surface of the water, in order to provide power to the paddles, such as lO by attaching it to the float. Respective wind turbines 455 are present in the apparatus in each of the end water storage tanks 405.

Claims

Claims 1. A water agitation apparatus for use with rainwater storage tanks, comprising: a paddle, for agitating water contained within a rainwater storage tank; and drive means contigured to impart motion to the paddle in response to an environmental condition.
2. The apparatus of claim t, wherein the drive means comprises: a float configured to be disposed on the surface of water within a rainwater storage tank; and a transmission coupling configured to impart motion to the paddle in response to a change in water level of water within a rainwater storage tank.
3. The apparatus of claim 2, wherein the transmission coupling comprises: a threaded axle configured to he disposed with its axial length substantially vertical within a rainwater storage tank; a sleeve having an internally threaded bore for receiving the threaded axle therein, and for cooperantig therewith; wherein movement of the float in a vertical direction induces longitudinal and rotational movement of the sleeve relative to the threaded axle, such that motion is imparted to the paddle for agitating water contained within a rainwater storage tank.
4. The apparatus of claim 3, wherein the paddle is substantially fixedly connected to the sleeve, and the sleeve is substantially rotatably connected to the float 5. The appantus of claim 3 or claim 4, wherein the threaded axle is substantially fixedly connectable to a rainwater storage tank.6. The apparatus of any preceding claim, wherein the drive means comprises a turbine and a transmission mechanism coupled between the turbine and the paddle.7. The apparatus of claim 6, wherein the turbine comprises a wind turbine.3. The apparatus of any one of claims 6 and 7, wherein the turbine comprises a water turbine conflgured to he powered by rainwater conveyed through a rainwater downpipe.9. The apparatus of any one of claims 6 to 8, wherein the transmission mechanism has a gear ratio of between 1:1 and 100:1 10. The apparatus of any preceding claim, wherein the drive means comprises a photovoltaic cell coupled to an electric motor.II. A method of agitating water contained within a rainwater storage tank, comprising: 1 5 providing an apparatus according to any preceding claim; and agitating water within the rainwater storage tank in response to an environmental condition.12. An apparatus substantially as hereinhefore described with reference to the accompanying drawings.Amendments to the claims have been filed as follows: Claims 1. A water agitation apparatus for use with rainwater storage tanks, comprising: a paddle, for agitating water contained within a rainwater storage tank; a float configured to he disposed on the surface of water within a rainwater storage tank; and a transmission coupling coupled to the float and configured to impart motion to the paddle in response to a change in water level of water within a rainwater storage tank. lo2. The apparatus of claim I, wherein the transmission coupling comprises: a threaded axle configured to he disposed with its axial length substantially vertical within a rainwater storage tank; a sleeve having an internally threaded bore for receiving the threaded axle 1 5 therein, and for cooperating therewith; wherein movement of the float in a vertical direction induces longitudinal and rotational movement of the sleeve relative to the threaded axle, such that CO motion is imparted to the paddle for agitating water contained within a rainwater storage tank. CO 20r 3. The appantus of claim 2, wherein the paddle is substantially fixe&y connected to the sleeve, and the sleeve is substantially rotatahy connected to the float 4. The apparatus of claim 2 or claim 3, wherein the threaded axle is substantially fixedly connectable to a rainwater storage tank.
5. The apparatus of any preceding claim, further comprising a turbine and a transnllssion mechanism coupled between the turbine and the paddin to impart motion to die paddle in response to wind.
6. The apparatus of claim 5, wherein the turbine comprises a wind turbine.
7. The apparatus of any one of claims 5 and 6, wherein the turbine cornpnses a water turbine configured to be powered by rainwater conveyed through a rainwater downpip e.
8. The apparatus of any one of claims 5 to 7, wherein the transmission mechanism has a gear ratio of between 1:1 and 100:1.
9. The apparatus of any preceding claim, further comprising a photovoltaic cell coupled to an dectrie motor to impart motion to the paddle in response to sunlight.
10. A method of agitating water contained within a rainwater storage tank, comprising: providing an apparatus according to any preceding claim; and agitating water within the rainwater storage tank in response to a change in water level of water within a rainwater storage tank.
11. An apparatus substantially as hereinhefore described with reference to the accompanying drawings. r