AU2007201335A2 - Tank assembly - Google Patents

Description

1 TANK ASSEMBLY This invention relates to a tank assembly suitable for installation under the ground. As increasing pressures are made on existing water resources, there is a need for a cost effective measure to help reduce potable water consumption. This invention targets the re-use of 'grey water' which via existing plumbing is normally discharged to traditional town sewerage treatment systems or on site septic systems. The 'grey waters' that are being targeting for re-use include shower, washing machine, bath and basin. This grey water has minimal levels of fats and faecal matter and is diverted to the underground tank assembly of the invention for collection and potential reuse. The target applications for this recycled water are toilet cisterns and gardens.

Current legislation states that grey water is not allowed to be stored for re-use but certain local governments now approve of grey water to be used on garden beds and lawns, which can be up to 24% of household's daily water usage. This water can be fed into a garden drip irrigation system for example. It would be desirable for this grey water to be collected so that the water can be re used for the garden, and with further filtration and/or deodorisation the water can also be used for toilet flushing rather than going down the sewer pipes as waste. (The potable water used for toilet flushing alone typically amounts to 18% of a household's daily usage of anywhere from 300 to 500 litres per day). These actions together will reduce potable water consumption potentially by up to 42% and also minimizes demand on the town sewerage treatment systems.

143146_1.DOC 2 Reference may be made to conventional grey water holding tank e( d assemblies and thus reference may be made to International Publication WO 85/05649 which describes conveying grey water or wastewater from kitchens, baths, showers and washstands to a receptacle where the grey t' 5 water undergoes pre-clarification before being fed to desired locations which include gardens and toilet flushes. In this arrangement unclarified or dirty water can be discharged directly onto the garden or the clarified or purified N waste water can be discharged onto the garden.

Reference also may be made to WO 94/05866 which describes a method of recycling wastewater which includes collecting and storing grey water in a holding tank assembly wherein a make-up water supply is provided to the holding tank assembly for maintaining the water level therein at desired levels. Water is delivered to a water flush toilet from the holding tank assembly. Grey water may be gravitationally fed to the holding tank assembly. There is also provided an overflow system.

Reference also may be made to FR 2662454 which describes collection, recycling and storage of domestic waste and rainwater with dive'rsion of wastewater and three stage filtration for domestic use but not consumption.

Reference also may be made to AU 200154264 and AU 2006201062 which each describe a system for controlling the re-use of grey water from a reservoir having a first valve member operable to open and close an inlet port and an outlet port in fluid communication with a discharge outlet. This invention is characterised by the use of a pressure control valve which 143146_1.DOC functions in combination with the first valve member to control flow of grey water through the inlet port and also through an outlet port.

However none of the prior art referred to above refers to an underground tank assembly which is designed to ensure that there is no build up of odour or bacteria in the underground tank assembly because grey water is continually being flushed from the tank assembly which is preferably located in the ground.

It is therefore an object of the invention to provide an underground tank assembly which substantially complies with this objective.

The invention in one aspect therefore refers to a tank assembly which has an internal compartment, an inlet for entry of grey water, an outlet for removal of grey water, wherein said outlet is in fluid communication with a sewer or waste disposal system and there is also provided a pump for pumping the grey water in the hollow internal compartment to a desired location inclusive of the garden or water closet characterised in that there is provided valve means for opening or closing of said outlet to maintain the volume of grey water in the hollow internal compartment to a desired level.

The underground tank assembly may include a tank having said internal compartment which has a cover attachable thereto. The tank is preferably inserted into a concrete pit in the ground. The inlet is suitably located in a side wall of the tank although it may be located in a top wall or cover if required. The inlet may be in fluid communication with conduits associated with a washing machine, dishwasher, shower, basin, sink or vanity unit.

143146_1.DOC The outlet is suitably located adjacent a base wall of the tank or may e( d be located in the base wall if required although this is a less preferred option.

Preferably the outlet is substantially at a similar level in the ground to the sewer as this will facilitate discharge of the wastewater directly into the c 5 sewer.

t'q The pump used for pumping grey water to the garden or WC may be any suitable type including a rotodynamic pump or a positive displacement pump. Examples of rotodynamic pumps include a centrifugal pump which may use a rotating impeller to increase the velocity of fluid as it passes through the pump. Examples of positive displacement pumps include a piston and cylinder arrangement with suction and discharge valves integrated into the pump.

The valve means for opening or closing of the outlet may be solenoid controlled as described hereinafter or more preferably use is made of a float controlled valve as also described hereinafter. The solenoid or float control mechanism may be used to cause opening or closing of a gate valve but use may be made of valve means having a movable valve member which may be a valve member moving longitudinally against the bias of a spring or a rotary valve member.

The invention in another aspect refers to a method of disposal of grey water which includes the steps of: passing the grey water into a tank; (ii) pumping the grey water from the tank to a desired location inclusive of a garden or water closet; and 143146 _.DOC (iii) also at the same time discharging the grey water to a sewer or drain location through an outlet of the tank wherein said outlet is controlled by a valve assembly whereby the volume of grey water located in the tank is maintained at a desired level and below a maximum capacity of the tank.

Reference may be made to a preferred embodiment of the invention shown in the accompanying drawings wherein: FIG 1 is a side view of the underground tank assembly of the invention showing a solenoid valve in a closed position; FIG 2 is a similar view to FIG 1 showing the solenoid valve in an open position; FIG 3 is a perspective view of the solenoid valve shown in FIG 2; FIG 4 is a side view of the underground tank assembly showing use of a float valve in the closed position; FIG 5 is a similar view to FIG 4 showing the float valve in an open position; and FIG 6 is a perspective view of the float valve shown in FIGS 4 to In FIG 1 there is shown underground tank assembly 10 having a body 11 and a cover 12. Both cover 12 and body 11 can be attached to each other by mating flanges 13 and 14 which can be connected to each other by suitable fasteners (not shown) or by adhesive. Body 11 can be inserted into a concrete pit (not shown) underneath flange 14. Normally both flanges 13 and 14 are flush with ground level 15 shown in phantom. Cover 12 is also provided with venting aperture 16. There is also provided aperture 9 which is 143146_1.DOC in fluid communication with pump 18 through a conduit (not shown) which pumps grey water onto the garden for example, aperture 8 for provision of an electrical supply to pump 18 and aperture 7 for passage of chlorine tablets or "bombs" for sterilisation purposes. FIG 1 also shows inlet 17 which is connected by a conduit (not shown) which is connected to one or more sources of grey water which may include showers, sinks, washing machines and dishwashers. It also will be appreciated that the term "grey water" may also include water from wells, rivers, dams and the like as well as storm water and run off from roofs.

There is also shown pump 18 and outlet 19 to a sewer (not shown).

There is also provided a solenoid valve 20 wherein solenoid 21 is connected to a source of electric current by lead 22 and when activated the resultant electrical energy is converted into mechanical energy which in turn opens or closes valve 20 automatically. This results in movement of valve member 22 which is held in desired location by fixed brackets 23 and 24. In FIG 1 the valve member 22 has closure flap or gate 26 attached thereto by pin 25 and opposed brackets 28 best shown in FIG 3. FIG 3 also shows body 11 having an internal compartment 35. FIG 1 shows the closed position while FIG 2 shows the open position. In the case of flap 26 being held continuously in the open position the grey water may be continuously charged to the sewer through outlet 19 as shown by arrow 27 while pump 28 is shut off. In this case tank assembly 10 may function as an inspection chamber. Normally when pump 28 is activated this will pump the grey water through a suitable conduit (not shown) associated with aperture 9 to the lawns, gardens, WC or 143146_1.DOC other suitable location and may be used per se or to supplement the supply of water from other sources.

However more preferably pump 18 is kept activated and thus valve is used to prevent the water in body 11 from ever reaching the limit of its capacity. When the supply of water in body 20 reaches a certain level as indicated by a microswitch 29 located on bracket 24 as shown in FIG 1 then this will activate solenoid 21 to open flap 26 as shown in FIG 2. This will maintain the underground tank assembly 10 at a desired 50% capacity.

In FIGS 4 to 6 reference is made to another embodiment of the invention showing underground tank assembly 1 OA wherein there is provided a float valve assembly 30 having a pair of floats 31 which are interconnected by a link 32 attached to each float 31 by fasteners 33 and weights 34.

Weights 34 can be used to control closing of float valve assembly Therefore weights 34 can be variable in size. Link 32 is attached to a pivot rod 36 by fastener 37. Pivot rod 36 has protrusion 38 pivotally attached to opposed lugs 39 in support platform 47 by pivot pin 40. There is also provided pneumatic damping mechanism 41 which controls the rate of closure of flap 26. Pneumatic damping mechanism 41 has adjustment screw 42, 1 barrel 43 and cylinder 44 which is attached to support platform 47.

Support platform 47 also has attached thereto barrel 43. There is provided a spindle 46 which has attached thereto a rubber flap (not shown) moveable in cylinder 44. Spindle 46 is also attached at its lower end to support bracket assembly 45 by fastener 9. Adjustment of adjustment screw 42 controls the amount of air in cylinder 44. In fact pneumatic damping mechanism 41 may 143146_ .DOC correspond to a conventional pneumatic door closer.

Float valve assembly 30 also has a control rod 48 attached to link 32 by fasteners 49. Control rod 48 has a downwardly extending strap 50 and a toggle lever 51 connected to strap 50 by springs 52 and 53. Toggle lever 51 is pivotally attached to control rod 48 at 54 and has an offset end 55 pivotally attached to support rod 56 at 57. Support rod 56 is attached to floor 58 of internal compartment 35 by bracket 59. Support rod 56 is attached by mounting plate 61 to closure flap 26. There are also provided link 62 pivotally attached to control rod 48 at 63 and also pivotally attached to crank 64 at Crank 64 is pivotally attached to support bracket 66 at 67 and 68. Control rod 48 is also pivotally attached to support bracket 66 at 69.

In use the operation of float valve assembly is shown in FIGS 4 to wherein in the closed position closure flap 26 firmly abuts a peripheral edge portion 70 of outlet 19 as shown in FIG 4. However closure flap 26 is moved to an open position spaced from peripheral edge 70 as shown in FIG 5 and this is caused by movement of floats 31 in relation to the water level in compartment 35. Movement of floats 31 causes pivotal movement of control rod 48 which also causes corresponding pivotal movement of toggle lever 51, link 62 and crank 64. This in turn causes movement of support rod 56 as shown which causes outward movement of flap 26 relative to outlet 19 as shown. The use of springs 52 and 53 in combination with toggle lever 51 causes a sudden outward movement of flap 26 when control rod 48 is nearing the end of its pivotal movement. In FIG 4 water is at lower level and in FIG 5 water is at higher level 71.

143146 1.DOC In the embodiment of FIGS 4 to 6 the function of underground tank assembly 10A is the same as described above in relation to underground tank assembly 10 wherein pump 18 may be activated and pump water continuously from inlet 17 and to the sewer 19 as shown by arrow 27 in FIG 2. In this mode of operation flap 26 is maintained in the open position.

Alternatively float valve assembly 10 operates as shown to maintain the maximum level of water in internal compartment 35 at about 50% and thus there is insufficient time for grey water in tank assembly 10 or 10 A to become rancid or form an offensive odour.

The main advantage of the tank assembly of the invention is to enable grey water to be collected without exceeding the relevant capacity of the tank. One can also have the option of using the tank assembly of the invention as an inspection chamber if required. If the collected water is not periodically pumped from the tank, the volume of water will increase and thus activate automatically the valve controlled outlet closure. The effect of this is to ensure that there is no odour or bacteria build up. This also eliminates sludge build up and the tank can be readily accessed for periodic inspection and maintenance. To further ensure that there is no possibility of extended retainment of grey water there may be provided a bleed valve (not shown) which facilitates drainage from the tank of any water that has not passed through the valve controlled outlet.

If the householder does not wish to re-use their grey water, tank assembly 10 or 10A can be set to a flow through setting where the wastewater flows through in a normal manner to the sewer, and naturally no 143146_1.DOC maintenance would be required in this setting. This is achieved by maintaining the outlet closure in a permanently open position.

The tank assembly of the invention can be installed to existing dwellings and ideally to new dwellings. At this stage it can be seen that the tank assembly of the invention being installed to households as a mandatory requirement for the re-use of water to gardens and irrigation systems. As environmental and political pressures increase for the supply of potable water the tank assembly of the invention may be retrofitted with existing filtration and pump technologies to enable the water to be used for interior household applications such as toilet cisterns.

In the instance of a new dwelling being built, the tank assembly can be installed and the plumbing designed to incorporate at a future point in time the collection of water from the bath, the basin, the shower and the laundry, all for re-use. Equally this applies to multi-storey developments.

While the tank assembly may be unlimited in size, approximate and preferred dimensions for household application are 1000mm long by 450mm deep and 450mm wide. The tank assembly may suitably have a capacity of 200 litres. The outlet 19 of the tank assembly should not be below the level of the sewerage line to which it is to be connected. While the depth of the tank can be altered, it is necessary to bear in mind cleaning and maintenance requirements. The cover 12 of the tank assembly 10 or 10 OA is removable and is sealed when fixed in position. The top surface of the tank assembly may have a rebate (not shown) around its perimeter that is sealed with an O-ring (not shown) to prevent gases or odour from the sewer from 143146_1.DOC 11 escaping the tank assembly.

The tank assembly can be formed from any non-ferrous and nonporous material such as fibreglass, concrete, HDPE or similar that is suitable for sanitary use. Stainless steel components may also be used.

If desired, above outlet 19 there may be an overflow spigot (not shown) which is in flow communication with the sewer which can be connected to an overflow conduit if the valve assembly becomes inoperative or outlet 19 becomes blocked.

Closure member 26 may have a rubber seal that closes to create a watertight seal when in the closed position.

143146_1.DOC

Claims (19)

1. A tank assembly for processing of grey water having an internal compartment, an inlet for entry of grey water, an outlet for removal of grey water which is in fluid communication with a sewer, drain or waste disposal system and a pump for pumping the grey water contained in the internal compartment to a desired location inclusive of a garden or water closet characterised in that there is provided valve means for opening or closing of said outlet to maintain the volume of grey water in the hollow internal compartment to a desired level.

2. A tank assembly as claimed in claim 1 which is inserted into the ground to function as an underground tank assembly.

3. i A tank assembly as claimed in claim 2 wherein the tank assembly is inserted into a concrete pit in the ground.

4. A tank assembly as claimed in any preceding claim wherein the inlet is located in a side wall of the internal compartment.

A tank assembly as claimed in claim 4 wherein the inlet is in fluid co mmunication with conduits associated with a washing machine, dishwasher, shower, basin or sink.

6. A tank assembly as claimed in any preceding claim wherein the outlet is substantially the same level as the sewer.

7. A tank assembly as claimed in any preceding claim wherein the valve means is solenoid controlled.

8. A tank assembly as claimed in claim 7 wherein there is provided a movable valve member wherein movement of the valve member is controlled 143146_1 .DOC by the solenoid and said valve member is attached to a closure flap or gate which will close or open the outlet upon movement of the valve member.

9. A tank assembly as claimed in claim 8 wherein the valve member is vertically reciprocatable.

10. A tank assembly as claimed in claim 8 wherein movement of the valve member is activated by a microswitch located in the internal compartment when the level of grey water in the internal compartment is at substantially the same level as the microswitch.

11.' A tank assembly as claimed in claim 10 wherein the microswitch is located on a support bracket for said movable valve member.

12. A tank assembly as claimed in any one of claims 1 to 6 wherein the valve means is float controlled.

13. A tank assembly as claimed in claim 12 wherein the valve means includes one or more floats pivotally connected to a pivot rod connected to a pneumatic or hydraulic damping assembly for control of rate of closure of the outlet.

14. A tank assembly as claimed in claim 13 wherein the damping assembly has an adjustment screw for adjusting the rate of closure of the outlet.

15'. A tank assembly as claimed in claim 13 or 14 wherein the or each float has one or more weights associated therewith for control of closure of the outlet.

16. A tank assembly as claimed in claims 13 to 15 wherein the or each float is pivotally connected to a control rod which is pivotally connected to a 143146_1 DOC toggle lever which toggle lever is pivotally connected to a movable support rod attached to a closure flap or gate of the outlet.

17. A tank assembly as claimed in claim 16 wherein the toggle lever is connected by one or more springs to the control rod or an outward extension thereof.

18. A tank assembly as claimed in claim 16 or 17 wherein the control rod at an end remote from the or each float is pivotally connected to a link which is pivotally connected to a crank which crank is pivotally connected at each end thereof to a support bracket attached to a side wall of the internal compartment.

19. A method of disposal of grey water which includes the steps of: passing the grey water into a tank; (ii) pumping the grey water to a desired location inclusive of a garden or water closet; and (iii) also at the same time discharging the grey water to a sewer, drain or waste disposal system through an outlet of the tank wherein said outlet is controlled by a valve assembly whereby the volume of grey water located in the tank is maintained at a desired level and below a maximum capacity of the tank. 143146_1.DOC