AU659900B2 - Sedimentary filter with by-pass overflow - Google Patents

Description

659900 41196 GEH:PFB P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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Name of Applicant: DALE J, PRIOR Actual Inventor: DALE J. PRIOR .Address for Service: COLLISON CO.,117 King William Street, Adelaide, S.A. 5000 Invention Title: SEDIMENTARY FILTER WITH BY-PASS OVERFLOW Details of Associated Provisional Applications: AUSTRALIAN Patent Application No. PL0168 Dated 24th December 1991 The following statement is a full description of this Invention, Including the best method of performing it known to me: 2 This invention relates to water filters, more particularly to filters through which rainwater passes as it flows to a storage tank for human consumption.

BACKGROUND OF THE INVENTION.

In many countries, and particularly in Australia it is virtually a necessity for rain water to be collected for domestic use, particularly for drinking. However there are often long periods of time where there is no rainfall and thus there collects on the roof and in the gutters dust, leaves and also other pollutants.

However in some areas where there are large industrial factories, such as iron ore and lead smelters, there is often passed into the atmosphere Industrial to 0 10 pollutants, and one of the most dangerous of these pollutants is lead. This lead is found in the drinking water collected from the roofs of buildings in these areas, and it is strongly recommended by health officials that this water be not consumed, However there is the temptation to drink this water for the public water supply in these areas Is not as Ideal as It may be, 15 There is evidence to show that there is a close link between high blood lead and 0 the drinking of rain water collected from roofs in these areas. It has been hypothesised that lead dust and flakes of lead based paint collect on the roofs during long periods of no rainfall together with leaf litter and other organic material. At times of rain this material together with material that has previously collected in the gutters is washed into the rainwater tanks. The theory is that once in the water in the tanks this leaf litter begins to "ferment" which results in the S" production of complex organic acids as well as some organic acids, These react with the lead salts in the dust and paint fragments to produce soluble lead, All of the "Insoluble" salts of lead have a "solubility product" and if kept in contact with water will attain a dynamic equilibrium to produce saturated solutions.

It is known that filters are used for removing or separating impurities from liquids.

Examples of filters which could be used for the filtering of rain water are JP3026320, AU9063881, DE3844658, DE3819962, DE3828008, DE2203512 and CH674860. However it appears that none of these would be satisfactory for removing lead from the water However it has been found that by using suitably designed sedimentation filters that all or substantially all of this solid material does not enter the tank and so the lead levels of the rain water would be reduced.

Thus it is an object of this invention to provide a filter which will reduce the amount of solid material entering a rain water tank, It is a further object of this invention to provide a filter which reduces the lead level in rain water collected in rain water tanks.

It is a still further object of this invention to provide a by-pass so that when the tank is full, any further a ter collected from the roof by-passes the tank so that the likelihood of a build up of pollutants in the tank is avoided.

BRIEF STATEMENT OF THE INVENTION Thus there is provided according to the invention a sedimentary filter a 15 sedimentary filter for filtering rain water collected on a roof or other catchment area for storage in a tank, said filter having a prilnary sedimentation chamber, a secondary sedimentation chamber, means for feeding the collected rain water to i60*0: the lower portion of the first sedimentation chamber, a transfer pipe to transfer the water from the upper portion of the first sedimentation chamber to the lower 20 portion of the secondary sedimentation chamber, the water passing from the upper portion of the secondary sedimentation chamber to the tank, and means .,.•.being provided to bleed to waste from the bottom of both sedimentation chambers the sediment deposited in the each chamber, said means comprising an outlet at the bottom of each chamber, said flow through each outlet being restricted to :i 25 allow the major proportion of the water to pass through the respective chambers, 3A DESCRIPTION OF THE DRAWINGS In the accompanying drawingst- FIG. 1 shows one form of the Invention connected to a gutter and a rainwater storage tank, FIG. 2 illustrates In cross section one form of the invention, FIG. 3 shows a further form of the invention, *.w *9 0 0

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000* 9* *0 S 5 0 4 ot- FIG. 4 shows a still further form of the invention, FIG. 5 shows a form of bypass for the tank, FIG. 6 shows a further form of bypass for the tank, FIG. 7 shows a further form of the invention, FIG. 8 show a still further form, and FIG. 9 shows another example of the bypass.

DESCRIPTION OF 'HE PREFERRED EMBODIMENT.

As shown In FIG. 1 the filter 1 Is connected between the gutter 2 and the tank 3.

The filter 1 includes a primary sedimentary chamber 4 and a secondary sedimentary chamber 5. The down pipe 6 from the gutter 2 is connected to the lower end of the primary chamber 4. The upper end of the primary chamber 4 is connected by a transfer pipe 7 to the lower end of the secondary chamber 5, the upper end of the secondary chamber 5 having an outlet 8 connected to the inlet to the tank 3. The upper end of the primary chamber 4 Is connected to the 15 overflow of the tank 3, The bottom of the primary chamber 4 Is provided with a sediment drain 9 and also 0: .the secondary chamber 5 Is provided with a sediment drain 10. Both these are connected to a drain tube 11 while the sediment drain 9 from the primary chamber has an adjustable flow valve 12 which has two positions, for maximum and slow discharge. After a long period of no rain, the valve Is opened to the maximum on the first rain so that all dust, debris and other pollutants collected on the roof are washed off the roof and discharged without any of the filtered water S' being collected. The tap is then moved to the slow discharge position so that further pollutants are removed from the filter while the filtered water is collected.

Reference will now be made to FIG. 2 where like Items have the same numbers. It Is noted that in the secondary chamber 5 there Is provided a filter element 13 having a reduced outlet 14. It is to be particularly noted the relative proportions of the various components. The primary chamber 4 is of greater cross-sectional area than the down pipe 6, and also the outlet 14 from the filter element 13 is still 30 further smaller In cross-section. In this embodiment the tank does not have an overflow, but the chamber 4 is connected to an overflow pipe 16, the upper portion of this overflow pipe 16 being at the same height as the upper surface of the tank 3.

The operation of the filter will now be described with reference to FIG. 2. The water from the down pipe enters the primary, chamber with a downward motion forcing the pollutants to the bottom of the chamber to settle there and be discharged by the sediment discharge 9 which is open at all times. Thus these particles are taken directly out of the system, The water then begins to rise up the primary sedimentation chamber, and es this chamber has a much greater cross sectional area than the down pipe, the water will rise slowly up the primary chamber as the inflow of water also exceeds the discharge from the sediment discharge 9, The water as it rises past the Inlet from the down pipe then has to reverse direction to pass up the primary chamber. This reversal of direction causes the heavier particles to continue down to the bottom of the primary chamber to be discharged. Also as the water rises slowly up the primary chamber, the particles tend to settle out and thus be discharged also.

Furthermore any debris which was dry in the gutters, as it enters the primary chamber will now be forced under the water, where It absorbs water and would thus tend to sink to the bottom of the primary chamber, 20 The water would then flow via the transfer pipe 7 into the secondary sedimentation chamber 5 where again the particles would tend to settle to the bottom of the chamber 5. The water would then slowly rise up this chamber and pass though the filter element 13 to pass through the smaller outlet 14 Into the tank, It Is noted that the flow rate through the filter system is controlled, the outlet 14 acting as a flow restrictor. It will be appreciated that the slower the flow rate the greater the filtering effect, this allowing greater time for the pollutants and other debris to settle out Into the bottom of the chambers 4 and For the purest water, the pollution discharge valve can be left open at all times.

This allows most of the dust and finer pollutants that have accumulated on the roof and In the gutters to be isolated and automatically discharged directly out of the system on the first shower of rain, preventing them from reaching the tank.

After the Initial rain fall, for examples 10 minutes of steady rain, the sediment discharge valve can be turned to the slow position, so that less water passes out of this discharge valve and more will enter the tank. Also caps at the bottom of the two chambers can be removed for cleaning and removing pollutants not discharged through the sediment discharge lines, In this way the filter element can be removed for cleaning or replacement as necessary, In FIG 2, when the tank Is full, the excess water will pass out of the overflow 16, Also if for example the filter element 13 became blocked, the water would then pass out of the overflow 16.

Turning now to FIG, 3, there Is shown a further example of the Invention, which is similar to the embodiment of FIG, 2 except that the tank is provided with its separate overflow outlet 17. The filter wIll operate in the same manner, the overflow 16 be necessary in the event that the filter element 13 becomes blocked, ,6 FIG. 4 shows a further embodiment of the invention in single chamber form, The 15 filter has a sedimentation chamber 20, the Inlet 21 to the chamber 20 from the down pipe 22 being at the lower portion of the chamber 20, The chamber ncludes a filter element 23, through which the water must pass through to outlet The chamber 20 has at its bottom a sediment discharge outlet 25 with its regulating valve 26, The down pipe 22 has a bypass 27 in the event that the filter element 23 becomes blocked.

o:In this embodiment also It will be seen that the water enters the chamber near the bottom with a downward motion. As the water turns upwardly the particles will be caused by inertia and gravity to pass to the bottom of the chamber, On the Initial flow of water after the first rainfall after a dry period, virtually all of the initial **66 pollutants and debris will be flushed off the roof and gutters, and this will be discharged through the sediment discharge outlet Turnng now to FIG, 5 of the drawings, there is shown a bypass system for a tank when full of water, The tank 30 is shown as full of water to the level 31, The discharge pipe 32 from the filter system enters the tank 30 and continues across the tank. After passing through the ten4 AS ,n overflow pipe, the pipe 32 has a raised portion 33 leading to an overflow outlet 34, The pipe 32 inside the tank has a raised Inlet 35 to the tank, this inlet 35 being at a lower level than the overflow outlet 34, In this way, when the water level is below the level 31 which Is at the overflow outlet level, then any further water entering via pipe 32 will pass across the tank in pipe 32 direct to the outlet. In this way. if there are contaminants in the water in pipe 32, then these do not enter the tank FIG, 6 shows a system which has the effect of removing the heavier dissolved pollutants that are suspended at lower levels in a tank 40, as the fresh water enters, When the tank Is full, due to the position of the inlet of the overflow pipe 41, the water will sweep across the bottom of the tank to the overflow pipe carrying with It the heavier dissolved pollutants, and also some of the sludge from the bottom of the tank.

FIG, 7 shows a further form of the Invention, In which the filter Is constructed as a rectangular box with Internal panels to form the respective chambers, Thus, the Internal panel or wall 42 separates the chambers 4 and 7, the water flowing from the bottom of chamber 7 to the bottom of chamber 5, the bleed being from the i. 20 bottom of chamber FIG. 8 shows a similar rectangular construction, with the wall 43 dividing the chamber 4 from chamber 5 containing the filter. Wall 43 has a central opening, giving time for the water to rise In chamber 4, and then the particles to sink In chamber 5 before passing out through the filter.

FIG, 9 illustrates how the filter can be fabricated as part of a storage tank. While only a single sedimentary chamber is shown, it is to be realised that this can have multiple chambers as shown in FIGS. 7 and 8. In some instances the filter may not be required where heavy debris only Is removed, 8 While the invention is described with particular reference to the collection and filtration of rain water, It Is to be realised that the invention can be utillsed for the filtration of other fluids.

Thus with this filter it is to be noted that It Is the cross sectional area of the tube the like through which the fluid flows is or reduces the flow rate of the fluid. The distance travelled through the filter from the point of entry to the exit from the filter is what Increases the time taken allowing time for the pollutants to settle out of the water. Thus as the water travels slowly upwardly, this upward movement assists in the particles settling out of the water. The angle that the water enters the respective filter chambers encourages the particles to travel down to the bottom of the chambers due to their Inertia, The adjustable pollution discharge system allows the settling pollutants of a finer nature to be carried directly out of the 1 1system at a high volume when fully opened therefore preventing these pollutants from reaching the tank at all, When the adjustable discharge system Is adjusted to the slow position It continually discharges small amounts of pollutants as they fall to the bottom due to this downward movement, and thus do not collect on the bottom.

Thus it will be seen that due to the operation of the filters, virtually no solid pollutants enter the water tank. As the organic material is removed, together with 20 the particles of lead, the reaction cannot take place In the tank to form soluble lead to thus contaminate the water, In an alternate embodiment the sediment discharge can be made to operate automatically. An electronic device, such as sensor can be Installed to detect the clarity of the water, After the initial flush of contaminated water on the Initial rain after a period of dry weather, the sensor would detect that the water Is now clear and would then move the control valve to the slow discharge position, Alternately, a mehanical device or timer can also be used to measure the weight, volume or time of discharging ,,ater to then change the valve to the slow flow position.

In connection with the invention it will be seen that the lead particles and the organic matter is removed from the water, and also Is continually discharged from the filter so that the reaction cannot take place in the filter itself. If the filter retained 9 the separated debris in the filter in contact with the water, then the undesirable reaction would take place in the filter and so no benefit would be gained.

However by separating the debris and other material In the water, and immediately removing same from the filter, the lead content of the water is greatly reduced.

Thus there is provided in the tank fresh filtered water, which could be made commercially available for human consumption.

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Claims (7)

1. A sedimentary filter for filtering rain water collected on a roof or other catchment a,ea for storage in a tank, said filter having a primary sedimentation chamber, a secondary sedimentation chamber, means for feeding the collected rain water to the lower portion of the first sedimentation chamber, a transfer pipe to transfer the water from the upper portion of the first sedimentation chamber to the lower portion of the secondary sedimentation chamber, the water passing from the upper portion of the secondary sedimentation chamber to the tank, and means being provided to bleed to waste from the bottom of both sedimentation chambers the sediment deposited In the esch chamber, said means comprising an outlet at the bottom of each chamber, said flow through each outlet being restricted to allow the major proportion of the water to pass through the respective chambers. 2, A sedimentation filter as defined In claim 1 wherein the cross-sectional area of the primary sedimentation chamber is greater than the cross sectional area of the inlet to the said primary sedimentation chamber so that the water will rise slowly up the primary sedimentation chamber to allow time for the sediments and i other inclusions In the water to settle to the bottom of the chamber for discharge by the bleed means,

3. A sedimentation filter as defined in any one of the preceding claims wherein the cross sectional area of the secondary sedimentation chamber is also of ~greater cross-sectional area than the Inlet to the primary sedimentation chamber. 400•

4. A sedimentation filter as defined In any one of the preceding claims wherein there Is provided In the secondary sedimentation chamber a filter element to filter any further sediments and inclusions remaining In the water, o A sedimentary filter as defined in any one of the preceding claims, wherein the upper end of the primary sedimentation filter is connected to an overflow, so that on the tank being filled to capacity the water is by-passed so that It does not flow into or through the tank.

6. A sedimentary filter as defined in any one of the preceding claims characterised in that the inlet to the tank is provided with a pipe extending across the tank to an overflow outlet, the pipe having an aperture to permit water to enter the tank, said aperture being at a lower level than said overflow outlet.

7. A sedimentary filter as defined in any one of claims 1 to 5 wherein the overflow outlet from the tank is provided at the bottom of the tank, so that overflow water flows across the bottom of the tank to remove the heavier pollutants therefrom.

8. Water whenever collected from a sedimentary filter as defined In any one of the preceding claims.

9. A sedimentary filter substantially as hereinbefore described with reference to the accompanylng drawings. Dated this 24th day of March 1995 S 0 S. S S S DALE J. PRIOR By his Patent Attorneys, COLLISON CO 4~ ABSTRACT A sedimentary filter especially for the collection of rain water from the roofs of buildings. The filter includes at least one sedimentary chamber having dimensions such that the cross sectional area is long compared with the inlet, so that the rate of movement of water through the chamber is slow. The water enters towards the bottom of the chamber and exits at the top. The bottom of the chamber has a continuous bleed so that sediment is bled off and thus cannot pollute the water. 0 00 0* a 0