AU736222B2 - Filtration - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventor(s): Address for Service: LAWRENCE ERNEST EATON ame. Jorw a+14<+ 1^ Ppav'e a Sr fA-4u, Lawrence Ernest Eaton

INTELLPRO

Patent Trade Mark Attorneys Level D, 308 Edward Street BRISBANE, QLD, 4000 (GPO Box 1339, BRISBANE, 4001) Invention Title: FILTRATION Details of Associated Provisional Application(s) No(s): Australian Patent Application No. P01016 filed 16 July 1996.

The following statement is a full description of this invention, including the best method of performing it known to me:

FILTRATION

THIS INVENTION relates to filtration and in particular but not limited to a filter assembly and filter system suitable for filtering water. In one preferred embodiment the present invention is employed to filter water held in a swimming pool. The following example relates to a swimming pool but any source of water can be filtered using the present invention.

Present swimming pool filters employ sand, fabric cartridge or diatomaceous earth covered filter elements as the filter media. These filters have a number of disadvantages. One disadvantage is that they do not actively alter the composition of the water in any beneficial way. It would be advantageous to actually treat the water in a beneficial way during the filtering process. The applicant's efforts to use activated carbon as a filter media to bring about a chemical change during filtration of swimming pool water has given rise to a number of inventions having general application to filtration. Although in a preferred form the 15 present invention is used in combination and illustrated below in relation to a swimming pool filter it will be appreciated that the invention has more general o "application.

In one form there is provided a deformable filter element comprising a :..flexible closed container having a deformable wall, the container holding finely 20 divided granular filter material in yieldable contact with the deformable wall, the container having at least part thereof made from a porous flow through means so that when the filter element is inserted into a filter chamber, the dimensions and shape of the chamber cause the chamber to impinge upon the deformable wall such that the deformable wall and adjacent filter media yield to the chamber and adopt an intimate conformal relationship with the chamber. The chamber may or may not have inner projections or recesses to enhance the intimate contact between the chamber and the wall.

In a further form there is provided a filter assembly comprising a chamber and a deformable filter element confined within the chamber, the chamber having inwardly directed projections and/or recesses and the filter element being conformed to the projections or recesses. Preferably, the projections and/or recesses are comprised of one or more shoulders or ribs.

In another form there is provided a swimming pool filter system in combination with a swimming pool, the system comprising first and second filter chambers arranged in parallel flow arrangement, an inlet upstream of the filter .chambers and an outlet downstream of the fi Iter chambers, the inlet communicating d I with the swimming pool and the outlet returning filtered water to the swimming 3 15 pool, each filter chamber holding filter elements employing a granular filter medium a major portion of which is preferably finely divided carbon, pump means pumping the water through the filter and backwash means enabling flow of water through the filter chambers to be temporarily reversed in order to clean the filter S.media, the filter elements being deformable filter elements described above.

S 20 The flexible closed container is preferably a tube of inert elasticised porous fabric closed at each end after being filled with the finely divided granular filter media. The fabric is typically woven to a pore size of 10 to 100 denier with denier being optimum for use as a pool filter. The tube is typically closed by simply tying a knot in each end. The use of a tube is convenient as the fabric can be supplied as a continuous tube and cut to required length. Alternatively, the container can be supplied as a sock open at one end only and subsequently closed.

A single flexible closed container can be employed or multiple containers of differing filter capacity can be used in series within the chamber.

While other fabrics can be used a preferred fabric is made from nylon or lycra with 3% to 5% elastin.

The filter chamber is preferably formed as a lower portion of a filter housing there being provided respective inlet and outlets to the chamber, preferably the inlet and the outlets include a flow through closure means adapted to apply pressure to the filter elements to force the filter elements into conformal relationship with the chamber.

0) 4,.

The filter housing preferably includes an auxiliary chamber which can be .''42 .downstream of the filter elements, the auxiliary chamber holding water treatment 9, 2** 15 means selected from the following:a cone filter typically of .02 micron pore size to remove organic material such as bacteria, algae and protozoa; (ii) a high pressure filter to remove organic material such as bacteria, algae and protozoa; 20 (iii) an electrical chlorinator for processing salt water; (iv) an anode and cathode to deposit ions into the filtered water; ozone injecting means to inject ozone into the auxiliary chamber as a biocide.

Preferably the filter system includes a source of steri I ising/reactivating agent that can be used from time to time to sterilise and reactivate the carbon filters. The sterilising/reactivating agent is particularly useful where the filter assembly is used to filter drinking water.

The sterilisation/reactivation agent can be any suitable agent known for its sterilisation/reactivation properties. A typical agent is a hydrogen peroxide solution.

The filter media can be activated carbon although other media can be used.

The source of sterilisation/reactivation agent is typically a refillable hermetic container employed so that pressure generated within the container by the sterilisation/reactivation process results in the agent being supplied to the filter chambers under pressure at least while a waste outlet downstream of the filter is open.

In order that the present invention can be more readily understood and be put into practical effect, reference will now be made to the accompanying drawings 15 and wherein:- Figure 1 is a schematic diagram illustrating a filter system for a swimming pool; o'ol Figure 2 is a longitudinal section through the centre of a filter housing illustrated in Figure 1; 20 Figure 3 is a longitudinal sectional view similar to that of Figure 2 but with multiple filter elements employed within the filter chamber; Figures 4A and 4B are diagrams illustrating forward flow through the filter assembly of Figure 1; 6 Figures 5A and 5B are diagrams illustrating a reverse flow through the filter assembly of Figure 1 during a backwash operation; and Figure 6 is a section through a sterilisation/reactivation chamber for use in a preferred form of the invention.

Referring to the drawings and initially to Figure 1 there is illustrated a swimming pool filter system 10 in combination with a swimming pool 11, the swimming pool 11 holding water which flows into a skimmer box 12 and on a line through a pump 13, a pre-filter 14 and then into first and second parallel flow arranged filters 15 and 16. Each of the filters 15 and 16 hold granular filter medium the major portion of which is finely divided activated carbon. At a position downstream of the filters 15 and 16 respective ozone injection means 17, ,chlorinator 18 and anode-cathode ionisation means 19 are employed leading to a ,So return line 20. A sterilisation/reactivation chamber 21 is employed and this will be described below.

15 Referring now to Figure 2 there is illustrated a typical section through a filter or 16 of Figure 1. As can be seen the filter employs a cap 22 and a filter chamber 23 holding a filter element 24 between respective inlet and outlet screens and 26. A threaded collar 27 is employed to retain the cap 22 in sealing S"engagement with the chamber 23. Upon removal of the cap the filter element 24 S 20 can be changed. The cap 22 defines therein an auxiliary chamber 28 which can be used to house additional filters, ozone injection means, cone filters, high pressure filters, anode/cathode or other means utilised for treatment of the filtered water downstream of the filter element 24. Where electrodes are employed a typical voltage at around 6VDC is used.

The filter element 24 is made from a tube of elasticised fabric filled with activated carbon and tied at each end and then forced into the chamber to conform to the chamber, the element being rightly held by screens 25 and 26.

Referring now to Figure 3 a further embodiment of the present invention is illustrated wherein the filters 15 and 16 illustrated in section in Figure 2 is also illustrated in section in Figure 3 but in this case four filter elements 29, 30, 31 and 32 are employed in series within the filter chamber. They are made in the same way as the element 24 and retained in placed by screens 25 and 26 as before. In this case each of the filter elements 29, 30, 31 and 32 either contain different filter media or the filter media is of differing capacity so that there is progressively greater filtration taking place from the inlet end to the outlet end of the filter. Any suitable 6..

number of filter elements may be employed.

.Referring now to Figures 4A through 5B the operation of the filter assembly ,o~o '4 15 will now be described. As can be seen Figures 4A and 5A are plan schematics and Figures 4B and 5B are side view schematics, these figures illustrating forward flow through the filters 15 and 16 and reverse flow respectively. As can be seen valves are employed at A, B and C with the valves A and B being open, the valve A being "a three way valve causing flow as shown by the arrows in Figures 4A and 4B.

S" 20 The valve C is a waste valve used to dispose of backwashed water pumped through the filters during the backwash operation illustrated in Figures 5A and In this case the valve B returning the filtered water to the pool or to an outlet for drinking water is closed and valve A redirects the incoming water so that it flows 8 in the reverse direction through the filters 15 and 16 and out through the discharge valve C to waste.

When it is desired to use the sterilisation/reactivation chamber the carbon filter elements in the chambers 15 and 16 are isolated by closing off valves A and B. The chamber 21 is in this case charged with a 5% 10% hydrogen peroxide solution or other suitable steriliser/reactivator and the valve D is open until such time as a flow of liquid at the waste outlet C ceases. As the chamber 14 is hermetically sealed and gas is produced in the sterilisation/reactivation process, the gas and reactants bubble and flow to the top of the reservoir 21 and pressurised hydrogen peroxide solution within the reservoir is forced down into the filters despite any reaction that would otherwise inhibit this flow. At this time valves C •and D are closed so that the sterilisation process occurs under pressure.

o Once the sterilisation/reactivation process is completed the valves according to the backwash process illustrated in Figures 5A and 5B are opened and the filters o 15 are backwashed until all the hydrogen peroxide solution and reactants are removed.

The valves are then reconfigured in accordance with Figures 4A and 4B and the normal filtration process continues.

,Referring now to Figure 6 the interior of the chamber 21 is illustrated.

The chamber 21 includes a lid 33 enabling the chamber to be hermetically 20 sealed so that pressure can be generated above the sterilisation agent at 34. As process gases percolate up through neck opening 35 this forms an annular ring of pressure on the agent within the chamber 21 so that the agent is forced through inlet hole 36 to track down the inside walls of the neck 37 so the remaining agent 9 held within the chamber 21 flows into the filters under pressure notwithstanding gas percolating up through the neck opening 35. This occurs when the valve D is open to enable flow of agent down into the filters 15 and 16.

The applicant has found that the present invention takes approximately 5/8 the time to filter a swimming pool compared to sand and diatomaceous earth filters and as the activated carbon removes spent chlorine approximately half the usual amount of chlorine is required. The applicant has also found that activated carbon as used in the present invention in relation to swimming pools in particular alters the chemistry of the swimming pool water and this is of itself a significant advance over prior swimming pool arrangements.

Whilst the above has been given by way of illustrative example of the present invention many variations and modifications thereto will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as set forth in the appended claims.

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Claims (8)

1. A water filter system comprising first and second filter chambers arranged in parallel flow arrangement, an inlet upstream of the filter chambers and an outlet downstream of the filter chambers, the inlet communicating with a water reservoir, each filter chamber holding filter elements, pump means pumping the water through the filter and backwash means enabling flow of water through the filter chambers to be temporarily reversed in order to clean the filter media wherein the filter elements comprise a tube of inert elasticised porous fabric closed at each end after being filled with finely divided granular filter media.

2. A water filter system according to claim 1 wherein the fabric is made from yarn of 10 to 100 denier. 6 .Io,

3. A water filter system according to anyone of the preceding claims wherein 0*@e at least one of said filter chambers is formed as a lower portion of a filter housing oo~ there being provided an inlet and an outlet to the chamber, the inlet and the outlet including a flow through closure means adapted to apply pressure to the filter 00-° 0° element to force the filter element into conformal relationship with the chamber. 0'

4. A water filter system according to any one of the preceding claims wherein 0 the granular filter medium comprises a major portion of finely divided carbon. S• 5. A deformable filter element comprising a flexible closed container have a deformable wall, the container holding finely divided granular filter material in yieldable contact with the deformable wall, the container having at least part thereof made from a porous flow through means so that insertion of the filter element into the filter chamber causes the chamber to impinge upon the 11 deformable wall, the deformable wall and adjacent filter media yield to the chamber and adopt an intimate conformal relationship with the chamber.

6. A water filter assembly comprising a chamber and a deformable filter element confined within the chamber, the chamber having inwardly directed projections and/or recesses and the filter element being conformed to the projections or recesses.

7. A swimming pool filter system in combination with a swimming pool, the system comprising first and second filter chambers arranged in parallel or series flow arrangement, an inlet upstream of the filter chambers and an outlet 10 downstream of the filter chambers, the inlet communicating with the swimming pool and the outlet returning filtered water to the swimming pool, each filter chamber holding filter elements each being an inert porous fabric filter at least partially filled with finely divided carbon, pump means pumping the water through the filter and backwash means enabling flow of water through the filter chambers 1 5 to be temporarily reversed in order to clean the filter media. t; 8. A filter system according to any one of claim 7 wherein the outlet downstream of the filter returns filtered water to the pool. A filter system according to claim 1 where a single flexible closed container is employed holding filter media or multiple containers of differing filter capacity are used in series within at least one of said chambers. A filter element according to claim 6 wherein the flexible closed container is a tube of inert elasticised porous fabric closed at each end after being filled with finely divided granular filter media, the tube being closed by a knot in each end. ~-0 12

11. A filter element according to claim 6 or 9 wherein the container is made from nylon or lycra with 3% to 5% elastin.

12. A deformable filter element for liquid filtration substantially as herein described with reference to and as illustrated in the accompanying drawings. DATED this 2 2 nd day of May 2001 LAWRENCE ERNEST EATON, JAMES NORMAN ATKINSON and PETER JOHN STUART By their Patent Attorneys INTELLPRO 3 3 3 S**o 1 o e