WO2012060689A1

WO2012060689A1 - Water filtration apparatus with automatic backwash

Info

Publication number: WO2012060689A1
Application number: PCT/MY2011/000224
Authority: WO
Inventors: Moon Tuck Mak
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-11-03
Filing date: 2011-10-14
Publication date: 2012-05-10
Anticipated expiration: 2013-05-03
Also published as: KR20120047198A; KR20120082852A

Abstract

An apparatus for water filtration with an automatic backwash cycle includes a membrane water filter comprising an upper chamber (4), a lower chamber (2), and a single or plurality of filter membranes (31) separating said upper (4) and lower (2) chambers. After a period of the apparatus being in filtration mode, the filter membranes (31) become progressively less permeable, causing a siphon pipe (5) to initiate a backwash mode, whereupon unfiltered water from a feed cylinder (10) cleans the upstream side of the filter membranes (31) before being sucked out via the siphon pipe (5). After that, the water flows downwards from the upper chamber (4) into the lower chamber (2), as the direction of flow through the filter membranes (31) is reversed. This backwash goes on until the level of water in the upper chamber (4) falls to a point that causes a break in the siphon, resulting in a switch back to filtration mode.

Description

1

Water Filtration Apparatus With Automatic Backwash

FIELD OF INVENTION The present invention relates generally to installations for treating water, and more specifically to a water filtration apparatus using a filter membrane that is incorporated with an automatic backwash.

BACKGROUND OF INVENTION

In emergency zones such as areas affected by floods for example, people can be trapped or isolated without drinking water and without electricity. In survival situations and in some military situations drinking water may not be available. It can often be the case that water is abundant but dirty and turbid and thus not safely drinkable. In many situations the infrastructure of water purification, such as a mains water supply system, is destroyed, and the ability to transport in bottled or bagged clean drinking water is limited. It has been proposed to provide single or low use water purification devices that are disposed of after a single throughput of fluid. Such devices use a dead-end filter wherein all the fluid passes through the filter membrane, and all particles larger than the pore size of the membrane are retained at its surface. This means that the retained particles start to build up on the surface of the membrane such that the membrane pores become blocked. This blinding reduces the efficiency of the filtration process and eventually means that no more fluid can be filtered. It is thus desirable to provide an apparatus that can produce extended amounts of clean water in periods when or locations where there is no available electricity, or where electricity is scarce. SUMMARY OF INVENTION

The present invention seeks to ameliorate the aforementioned disadvantages by providing an apparatus that can produce extended amounts of clean water with or without the need for electricity using a membrane filtration apparatus that is able to self regulate the backwashing process.

This invention relates to an apparatus for water filtration with an automatic backwash cycle. The apparatus includes a membrane water filter comprising an upper chamber, a lower chamber, and a single or plurality of filter membranes separating said upper and lower chambers. The filter membranes are attached on a mounting plate via locking mechanisms, the mounting plate then positioned in between the upper and lower chambers. The filter membranes have an upstream side facing the lower chamber and a downstream side facing the upper chamber. During a filtration mode, unfiltered water is fed into said lower chamber via an inlet and passes via the said filter membranes into the upper chamber to become product water, thereafter exiting via an exit pipe located close to a top of upper chamber. A feed system feeds water to the water filter comprising a vertical feed cylinder and having a feed inlet at an intermediate point along the length of the feed cylinder for receiving unfiltered water and a feed outlet close to the bottom of said feed cylinder for expelling said unfiltered water into the lower chamber. A backwash system comprising a siphon pipe with one end in fluid connection to a bottom end of lower chamber, said siphon pipe then rising to a siphon point and then doubling back downwards and opening into a rectangular weir. An ejector system comprising a series of interconnected pipes with a first end in fluid connection with siphon pipe at a point lower than siphon point, a second end in fluid connection with siphon pipe at siphon point, and a third end opening into the rectangular weir. The said interconnected pipes are designed such that any fluid entering first end will fall downwards and through the ejector to exit into the third end and in so doing create a suction at the second end. A cup located at a lower end of upper chamber comprising a receptacle with a top opening. A siphon break line comprising an elongated pipe with an upper end in fluid connection with siphon pipe at siphon point and a lower end opening into and within said cup. After a period of the apparatus being in filtration mode, the filter membranes become progressively less permeable at the upstream side, thus causing the water level to rise in both the feed cylinder and the siphon pipe until the water starts flowing into the said first end of the ejector system, causing the ejector system to expel all the air from within the siphon pipe, thus initiating the backwash mode, whereupon unfiltered water from the feed cylinder cleans the upstream side of the filter membranes before being sucked out via the siphon pipe, in what is called an out-to-out backwash. When the unfiltered water level in the feed cylinder falls to a level that is lower than the level of said product water in the upper chamber, the product water in the upper chamber will flow downwards into the said lower chamber and be sucked out by the said siphon pipe, reversing the direction of flow through the filter membranes in what is called an in-to-out backwash. This backwash cycle goes on until the level of product water in the upper chamber falls to the lower end of the siphon break line whereupon air will be sucked into the said siphon break line (53), thus breaking the siphon and causing the apparatus to switch back to filtration mode. This apparatus is able to automatically switch from backwash mode to filtration mode in a repeatable fashion. A manual isolating valve is provided to allow control of a manual backwash. This isolating valve allows ejector pipes to be filled manually to accelerate the start of said siphon. Options exist for this isolation valve to be motorized to start the backwash cycle automatically via time/level/pressure differential controls. The rectangular weir allows fine tuning of the start of the backwash mode.

This invention also relates to an apparatus for water filtration with an automatic backwash cycle comprising: a membrane water filter comprising an upper chamber, a lower chamber, and at least one filter membrane separating said upper and lower chambers, said at least one filter membrane having an upstream side facing the said lower chamber and a downstream side facing the said upper chamber, wherein during a filtration mode, unfiltered water is fed into said lower chamber via an inlet and passes via the said at least one filter membrane into the said upper chamber to become product water, thereafter exiting said upper chamber via an exit pipe, said exit pipe located close to a top of said upper chamber; a feed system for feeding water to said membrane water filter comprising an incoming feed line in fluid connection with a hydro-pneumatic vessel and subsequently to a feed outlet, a pressure switch able to sense the pressure within said vessel; a drainage means comprising a drainage pipe connected at one end to a lower portion of said lower chamber and the other end draining out externally, and a motorized valve for controlling the flow within said drainage pipe, said motorized valve activated by said pressure switch whereby after a period of the apparatus being in filtration mode, the said at least one filter membrane becomes progressively less permeable at the said upstream side, causing the pressure in lower chamber to increase progressively until it allows part of the incoming feed water to enter the said hydro-pneumatic vessel until a predetermined pressure point is reached, causing the pressure switch to activate the motorized valve, which then opens the drainage pipe and initiates a backwash.

An air blower can be provided to introduce air bubbles into the lower chamber for scouring said filter membranes. The air blower can either be manually or automatically activated. This invention also relates to an apparatus for water filtration with an automatic backwash cycle comprising: a lower chamber; an upper chamber located above said lower chamber, and in fluid communication with said lower chamber; at least one connecting pipe, said at least one connecting pipe establishing the said fluid communication between said upper chamber and said lower chamber; at least one filter membrane located inside said lower chamber and dividing said lower chamber into a top section and a bottom section, each said section only fluid communicable to the other via said filter membrane, said at least one filter membrane having an upstream side facing said bottom section and a downstream side facing said top section, wherein during a filtration mode, unfiltered water is fed into said bottom section via an inlet and passes via the said at least one filter membrane into the said top section to become product water, thereafter flowing upwards into said upper chamber via said at least one connecting pipe, and exiting said upper chamber via an exit pipe, said exit pipe located close to a top of said upper chamber; a feed system for feeding water to said membrane water filter comprising a substantially vertical feed cylinder and having a feed inlet at an intermediate point along the length of said feed cylinder for receiving said unfiltered water and a feed outlet close to the bottom of said feed cylinder for expelling said unfiltered water, said feed outlet in fluid communication with said inlet; a backwash system comprising: a siphon pipe with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber, said siphon pipe then rising to a siphon point and then doubling back downwards and opening into a rectangular weir; an ejector system comprising a series of interconnected pipes with a first end in fluid connection with said siphon pipe at a point lower than said siphon point, a second end in fluid connection with said siphon pipe at said siphon point, and a third end opening into said rectangular weir. Said series of interconnected pipes designed such that any fluid entering said first end will fall downwards and through the ejector to exit into said third end and in so doing create a suction at the said second end; a cup located at a lower end of said upper chamber, said cup comprising a receptacle with a top opening; a siphon break line comprising an elongated pipe with an upper end (531 ) in fluid connection with said siphon pipe at said siphon point and a lower end opening into and within said cup whereby after a period of the apparatus being in filtration mode, the said at least one filter membrane becomes progressively less permeable at the said upstream side, thus causing the water level to rise in both the said feed cylinder and the said siphon pipe until the water starts flowing into the said first end, in turn causing the said ejector system to expel all the air from within the said siphon pipe, thus initiating the backwash mode, whereupon unfiltered water from the feed cylinder cleans the said upstream side of the at least one filter membrane and lower chamber before being sucked out via the siphon pipe until the unfiltered water level in the said feed cylinder falls to a level that is lower than the level of said product water in the upper chamber, whereupon the said product water in the upper chamber will flow downwards into the said lower chamber and be sucked out by the said siphon pipe, until the level of product water in the said upper chamber falls to the said lower end of the said siphon break line whereupon air will be sucked into the said siphon break line thus breaking the siphon and causing the apparatus to switch back to filtration mode, said apparatus able to automatically start and terminate the said backwash mode in a repeatable fashion. When required, the enhanced backwash can be carried out through repeated backwashing and air-scouring with or without chemicals.

This invention further relates to a method of water filtration with an automatic backwash cycle comprising the steps of:

a. feeding unfiltered water from a feed inlet into a substantially vertical feed cylinder at an intermediate point along said feed cylinder;

b. allowing said unfiltered water within said feed cylinder to drain into a lower chamber via a feed outlet;

c. filtering said unfiltered water from said lower chamber through at least one filter membrane into an upper chamber, in a filtration mode;

d. allowing the level of unfiltered water in a siphon pipe to rise as the said at least one filter membrane becomes increasingly less permeable, with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber, said siphon pipe then rising to a siphon point and then doubling back downwards and opening into a rectangular weir; e. emptying any air within the said siphon pipe via an ejector system, said ejector system comprising a series of interconnected pipes with a first end in fluid connection with said siphon pipe at a point lower than said siphon point, a second end in fluid connection with said siphon pipe at said siphon point, and a third end opening into said rectangular weir, said series of interconnected pipes designed such that any water entering said first end will fall downwards and through the ejector to exit into said third end and in so doing create a suction at the said second end, said emptying triggered when said level of unfiltered water in said siphon pipe reaches said first end; and f. triggering a backwash cycle once the said level of unfiltered water in the siphon pipe reaches said siphon point, whereby unfiltered water from the feed cylinder cleans the said upstream side of the at least one filter membrane before being sucked out via the siphon pipe until the unfiltered water level in the said feed cylinder falls to a level that is lower than the level of said product water in the upper chamber, whereupon the said product water in the upper chamber will flow downwards into the said lower chamber and be sucked out by the said siphon pipe; and

g. breaking the siphon when water level in said upper chamber falls below a lower end of a siphon break line, said siphon break line comprising an elongated pipe with an upper end in fluid connection with said siphon pipe at said siphon point and with said lower end opening into and within a cup, said cup located at a lower end of said upper chamber, hence switching water filter back to said filtration mode.

This method may further comprise the step of introducing externally stored product water back into the upper chamber during a planned or manual backwash cycle and adding a cleaning solution to the product water prior to this backwash cycle, then opening a manual isolating valve to drain off the upstream water in the said lower chamber and replacing it with said cleaning solution mixed water from the upper chamber, with the level of cleaning solution mixed water in the lower chamber kept just below the top of the said lower chamber, and allowing the cleaning solution mixed water to soak through the membranes for around 30 minutes, then rinsing the membranes through feed-filtration- manual drain cycles until the water is substantially free of cleaning solution. The cleaning solution can be any of chlorine, alkali, or acid solutions. This invention further relates to a filter component for use in a water filtration apparatus comprising: a mounting plate, said mounting plate sandwiched between an upstream and a downstream side of said water filtration apparatus, said mounting plate designed to be removable from said water filtration apparatus in a repeatable fashion; filter membranes located on said mounting plate, said filter membranes providing the filtering means between the said upstream and downstream sides. In one embodiment, each filter membrane is secured to the mounting plate by a locking mechanism. In another embodiment, there is a flexible rubber mounting piece located between each filter membrane and the mounting plate.

This invention is not limited to filtration of drinking water but in fact of any other suitable fluids such as industrial fluids, waste water, and seawater.

Other objects and advantages will be more fully apparent from the following disclosure and appended claims.

BRIEF DESCRIPTION OF DRAWINGS Figure 1 shows a cross-sectional view of a hopper-bottomed water filter with automatic backwash system in a first embodiment of this invention.

Figure 2 shows a cross-sectional view of a flat-bottomed water filter with a feed tank, automatic backwash system together with air-blower for air scouring and a manual isolating valve in a second embodiment of this invention.

Figure 3 shows a cross-sectional view of a hopper-bottomed water filter with a hydro- pneumatic tank, interlocking pressure switch and motorized valve, backwash system and air blower for air scouring in a third embodiment of this invention.

Figure 4 shows the filter membrane mounting plate system in a first embodiment of this invention. Figure 5 shows example configurations of filter membranes in an embodiment of this invention.

Figure 6 shows a cross-sectional view of a water filter with automatic backwash system in a fourth embodiment of this invention.

Figure 7 shows the filter membrane mounting plate system in a second embodiment of this invention. DETAILED DESCRIPTION OF INVENTION

It should be noted that the following detailed description is directed to a water filter with automatic backwash and is not limited to any particular size or configuration but in fact a multitude of sizes and configurations within the general scope of the following description.

Referring to Figure 1 , there is shown an apparatus for water filtration with an automatic backwash cycle in a first embodiment of this invention comprising an upper chamber (4), a lower chamber (2), and a single or plurality of filter membranes (31 ) separating said upper (4) and lower (2) chambers. The filter membranes (31 ) are attached on a mounting plate (3) via locking mechanisms (as shown in Figures 4 and Figure 7), the mounting plate (3) then positioned in between the upper and lower chambers. The filter membranes (31 ) have an upstream side facing the lower chamber (2) and a downstream side facing the upper chamber (4). The filter membranes (31 ) extend into the said lower chamber (2). During a filtration mode, unfiltered water is fed into said lower chamber (2) via an inlet (21 ) and passes via the said at least one filter membrane (31 ) into the said upper chamber (4) to become product water, thereafter exiting said upper chamber (4) via an exit pipe (42), said exit pipe located close to a top of said upper chamber (4). A feed system (1 ) feeds unfiltered water to said lower chamber (2) and comprises a substantially vertical feed cylinder (10) and a feed inlet (1 1 ) at an intermediate point along the length of said feed cylinder (10) for receiving said unfiltered water and a feed outlet (12) close to the bottom of said feed cylinder for expelling said unfiltered water into said lower chamber (2), said feed outlet (12) in fluid communication with said inlet (21 ). A backwash system comprises: a siphon pipe (5) with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber (2), said siphon pipe then rising to a siphon point (531 ) and then doubling back downwards and opening into a rectangular weir (61 ). An ejector system (51 ) comprising a series of interconnected pipes with a first end (511 ) in fluid connection with siphon pipe (5) at a point lower than siphon point (531 ), a second end (512) in fluid connection with siphon pipe at siphon point, and a third end (513) opening into the rectangular weir. The said interconnected pipes are designed such that any fluid entering first end (511) will fall downwards through its dropper (514) to feed the ejector (515) and through the ejector to exit into the third end (513) and in so doing create a suction at the second end (512). A cup (44) is located at a lower end of said upper chamber (4), said cup comprising a receptacle with a top opening. A siphon break line (53) comprises an elongated pipe with an upper end (531 ) in fluid connection with said siphon pipe (5) at said siphon point (531 ) and a lower end (532) opening into and within said cup (44).

After a period of the apparatus being in filtration mode, the said at least one filter membrane (31 ) becomes progressively less permeable at the said upstream side, thus causing the water level to rise in both the said feed cylinder (10) and the said siphon pipe (5) until the water starts flowing into the said first end (511 ), in turn causing the said ejector system (51 ) to expel all the air from within the said siphon pipe (5). This then initiates the "out-to-out" backwash mode, whereupon unfiltered water from the feed cylinder (10) cleans the said upstream side of the at least one filter membrane (31) and the lower chamber (2) before being sucked out via the siphon pipe (5). During this "out-to- out" backwash mode, the said unfiltered water level in the said feed cylinder (10) falls to the said feed outlet (12) level which results in the unfiltered water falling from the said feed inlet ( 1 ), thus inducing a stream of air bubbles to said inlet (21 ), said air bubbles enhancing cleaning of the said membranes. This continues until the unfiltered water level in the said feed cylinder (10) falls to a level that is lower than the level of said product water (42) in the upper chamber (4). When this happens, the said product water in the upper chamber (4) will flow downwards into the said lower chamber (2), so the direction of flow through the filter membranes (31 ) is reversed, and entrapped particles at the upstream end of the filter membranes (31 ) and lower chamber (2) are substantially removed, in what is known as an "in-to-out" backwash mode. This "in-to-out" backwash mode continues until the level of product water in the said upper chamber (4) falls to the said lower end (532) of the said siphon break line (53) whereupon air will be sucked into the said siphon break line (53), thus breaking the siphon and causing the apparatus to switch back to filtration mode. The apparatus is able to automatically switch between backwash mode and filtration mode in a repeatable fashion. The flow rate through the said filter membrane (31 ) during the backwash mode is at least twice the flow rate during the filtration mode.

In a preferred embodiment, the diameter of the said siphon pipe (5) is larger than the diameter of the said interconnected pipes of the ejector system (51 ) and the diameter of the said elongated pipe of the siphon break line (53).

Referring to Figure 2, there is shown an apparatus for water filtration with an automatic backwash cycle in a second embodiment of the present invention. The concept is similar to the first embodiment in that a siphon is automatically triggered once an amount of particles have collected in the filter membranes (31 ). In this second embodiment, the water filtration with automatic backwash cycle device comprises an upper chamber (4), a flat bottomed lower chamber (2), and a single or plurality of filter membranes (31 ) separating said upper (4) and lower (2) chambers. The filter membranes (31 ) are attached on a mounting plate (3) via locking mechanisms (as shown in Figure 4 and Figure 7). The mounting plate (3) is positioned between the upper (4) and lower (2) chambers. The filter membranes (31 ) have an upstream side facing the lower chamber (2) and a downstream side facing the upper chamber (4). The filter membranes (31 ) extend into the said lower chamber (2). During a filtration mode, unfiltered water is fed into said lower chamber (2) via an inlet (21 ) and passes via the said at least one filter membrane (31 ) into the said upper chamber (4) to become product water, thereafter exiting said upper chamber (4) via an exit pipe (42), said exit pipe located close to a top of said upper chamber (4). A feed system (1 ) feeds unfiltered water to said lower chamber (2) and comprises a substantially vertical feed cylinder (10) and a feed inlet (11) at an intermediate point along the length of said feed cylinder (10) for receiving said unfiltered water and a feed outlet (12) close to the bottom of said feed cylinder for expelling said unfiltered water into said lower chamber (2), said feed outlet (12) in fluid communication with said inlet (21 ). A feed tank (14) is connected to the top of the said vertical feed cylinder (10).

A backwash system comprises: a siphon pipe (5) with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber (2), said siphon pipe then rising to a siphon point (531) and then doubling back downwards and opening into a rectangular weir (61 ). An ejector system (51) comprising a series of interconnected pipes with a first end (511 ) in fluid connection with siphon pipe (5) at a point lower than siphon point (531 ), a second end (512) in fluid connection with siphon pipe at siphon point, and a third end (513) opening into the rectangular weir. The said interconnected pipes are designed such that any fluid entering first end (511 ) will fall downwards through its dropper (514) to feed the ejector (515) and through the ejector to exit into the third end (513) and in so doing create a suction at the second end (512). A cup (44) is located at a lower end of said upper chamber (4), said cup comprising a receptacle with a top opening. A siphon break line (53) comprises an elongated pipe with an upper end (531) in fluid connection with said siphon pipe (5) at said siphon point (531) and a lower end (532) opening into and within said cup (44). After a period of the apparatus being in filtration mode, the said at least one filter membrane (31 ) becomes progressively less permeable at the said upstream side, thus causing the water level to rise in both the said feed cylinder (10) and into the said feed tank (14) and siphon pipe (5) until the water starts flowing into the said first end (51 1 ), in turn causing the said ejector system (51 ) to expel all the air from within the said siphon pipe (5). This then initiates the "out-to-out" backwash mode, whereupon unfiltered water from the feed tank (14) and feed cylinder (10) cleans the said upstream side of the at least one filter membrane (31 ) and the lower chamber (2) before being sucked out via the siphon pipe (5). During this "out-to-out" backwash mode, the said unfiltered water level in the said feed cylinder (10) falls to the said feed outlet (12) level which results in the unfiltered water falling from the said feed inlet (1 1 ) thus inducing a stream of air bubbles to said inlet (21 ), said air bubbles enhancing cleaning of the said membranes (31). This continues until the unfiltered water level in the said feed cylinder (10) falls to a level that is lower than the level of said product water (42) in the upper chamber (4). When this happens, the said product water in the upper chamber (4) will flow downwards into the said lower chamber (2), so the direction of flow through the filter membranes (31 ) is reversed, and entrapped particles at the upstream end of the filter membranes (31 ) and lower chamber (2) are substantially removed, in what is known as an "in-to-out" backwash mode. This "in-to-out" backwash mode continues until the level of product water in the said upper chamber (4) falls to the said lower end (532) of the said siphon break line (53) whereupon air will be sucked into the said siphon break line (53), thus breaking the siphon and causing the apparatus to switch back to filtration mode. The apparatus is able to automatically switch between backwash mode and filtration mode in a repeatable fashion. The flow rate through the said filter membrane (31 ) during the backwash mode is at least twice the flow rate during the filtration mode.

In a preferred embodiment, and shown in Figures 1 and 2, the diameter of the said siphon pipe (5) is larger than the diameter of the said interconnected pipes of the ejector system (51 ) and the diameter of the said elongated pipe of the siphon break line (53). In another preferred embodiment, and shown in Figures 1 and 2, there is provided a manual or automated motorized isolating valve (22), said isolating valve allowing control of backwash, especially useful for repeat enhanced backwashing, with or without the aid of air scouring and anti-fouling chemicals such as mild chlorine, acid and alkali.

Another manual or automated motorized isolating valve (23) could also be used as a desludging or cross flow device when handling highly turbid water, e.g. > 500 NTU. When cross flow is required, the said valve (23) is kept partially opened to allow a controlled and continuous bleeding of the more turbid water at the lowest end of lower chamber (2) to be drained unfiltered.

Referring to Figure 3, there is shown an apparatus for water filtration with an automatic backwash cycle in a third embodiment of this invention comprising an upper chamber (4), a lower chamber (2), and at least one filter membrane (31 ) separating said upper (4) and lower (2) chambers. The at least one filter membrane (31 ) are attached on a mounting plate (3) via locking mechanisms (as shown in Figure 4 and Figure 7), the mounting plate (3) then positioned in between the upper (4) and lower (2) chambers. The at least one filter membrane (31 ) have an upstream side facing the lower chamber (2) and a downstream side facing the upper chamber (4). The at least one filter membrane (31 ) extends into the said lower chamber (2). During a filtration mode, unfiltered water is fed into said lower chamber (2) via an inlet (21 ) and passes via the said at least one filter membrane (31 ) into the said upper chamber (4) to become product water, thereafter exiting said upper chamber (4) via an exit pipe (42), said exit pipe located close to a top of said upper chamber (4). A feed system (1 ) feeds unfiltered water to said lower chamber (2) and comprises an incoming feed line (10) in fluid connection to a hydro-pneumatic vessel (71 ), another fluid connection to a pressure switch / pressure indicator (72) and a feed outlet (12) for expelling said unfiltered water into said lower chamber (2), said feed outlet (12) in fluid communication with said inlet (21 ). The pressure switch (72) is a hydraulically actuated electrical switch that is actuated when the back pressure in the lower chamber (2) reaches the pre-determined set point. The actuation of the pressure switch (72) sends an electrical signal to open a motorized valve (73). This motorized valve (73) controls a drainage pipe (74) that is connected at a first end (741 ) to the bottom end of said lower chamber (2) and at a second end (742) to the drain. The motorized valve has a manual override which allows for manual control of backwashing when opened manually.

In this way, when the said filter membranes (31 ) become progressively less permeable after a period of the apparatus being in filtration mode, the pressure in lower chamber (2) will increase progressively to allow part of the incoming feed water to enter and stored inside the hydro-pneumatic vessel (71 ) eventually causing the said vessel to reach its predetermined stored volume of feed water and pressure set-point; also in turn, causing the pressure switch (72) to be activated and the motorized valve (73) to discharge the water through the drainage pipe (74). The stored water in pneumatic vessel (71 ) and that of the continuous in-coming feed water flows into the lower chamber (2) and out through the drainage pipe (74) to start an "out-to-out" backwash cycle. Soon after, the product water in the upper chamber (4) will flow downwards into the said lower chamber (2), so the direction of flow through the at least one filter membrane (31 ) is reversed, and entrapped particles at the upstream end of the filter membranes (31 ) and lower chamber (2) are substantially removed, through this final "in-to-out" backwash cycle with the said product water.

In both the second and third embodiments, illustrated respectively by Figures 2 and 3, there is shown an optional air blower (80). This air blower (80), which can be activated during the backwash mode, pumps air into the said lower chamber (2) and creates air bubbles as a scouring medium to better clean the said membranes (31 ). Referring to Figure 4, there is shown a filter component for use in a water filtration apparatus comprising a mounting plate (3), said mounting plate sandwiched between an upstream and a downstream side of said water filtration apparatus, said mounting plate designed to be removable from said water filtration apparatus in a repeatable fashion. At least one filter membrane (31 ) is located on said mounting plate, said at least one filter membrane providing the filtering means between the said upstream and downstream sides. Each of the said at least one filter membrane (31 ) is secured to the said mounting plate (3) by a locking mechanism (32). A handle (33) is fixed to each filter membrane (31 ) to facilitate removal from the mounting plates (3).

Figure 5 shows examples of how the filter membranes (31 ) are arranged within each mounting plate (3). In a circular configuration, practically any number of filter membranes (31 ) can be installed. As the number of filter membranes (31 ) is based on the turbidity and required output of the device, being able to customize the number of filter membranes (31 ) is very useful.

Referring to Figure 6, there is shown an apparatus for water filtration with an automatic backwash cycle in a fourth embodiment of this invention comprising a separate upper chamber (4) and lower chamber (2), and either a plurality of filter membranes (31) or a single filter membrane housed within the said lower chamber (2). Each filter membrane (31 ) is attached on a common mounting plate (3) via locking mechanisms as shown in Figure 4 or a rubber mounting piece shown in Figure 7. The mounting plate (3) is positioned to separate the lower chamber into two sections; the bottom section (2a) for unfiltered feed water and the top section (2b) for filtered product water. The filter membranes (31 ) have an upstream side facing the bottom section (2a) of the lower chamber (2) and a downstream side feed into the top section (2b) of the lower chamber (2). The filter membranes (31 ) extend into the said bottom section (2a) of lower chamber (2). During a filtration mode, unfiltered water is fed into said bottom section (2a) of lower chamber (2) via an inlet (21 ) and passes via the said at least one filter membrane (31 ) out from the bottom section (2a) of lower chamber (2) and into the fop section (2b) of lower chamber (2) as product water, thereafter exiting said top section (2a) of chamber (2) via an outlet pipe (2c), said outlet pipe located around the highest point of top section (2b) of lower chamber (2). In a preferred embodiment, the diameter of the outlet pipe (2c) is at least equal if not larger than the diameter of the siphon pipe (5). The product water flows though outlet pipe (2c) into the said upper chamber (4) and in fluid connection with product inlet connector (41 ) located near bottom of said upper chamber. After product water has filled to its designed volume in upper chamber (4), it will exit the said upper chamber via an exit pipe (42), said exit pipe (42) located close to the top of said upper chamber (4). Product water can also flow from the highest point of top section (2b) of lower chamber (2) straight to the exit pipe (42). A feed system (1 ) feeds unfiltered water to said lower chamber (2) and comprises a substantially vertical feed cylinder (10) and a feed inlet (1 1 ) connected closed to the top of said feed cylinder (10) for receiving said unfiltered water and a feed outlet (12) close to the bottom of said feed cylinder for expelling said unfiltered water into said lower chamber (2), said feed outlet (12) in fluid communication with said inlet (21 ). A backwash system comprises: a siphon pipe (5) with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber (2), said siphon pipe then rising to a siphon point (531 ) and then doubling back downwards and opening into a rectangular weir (61 ). An ejector system (51 ) comprising a series of interconnected pipes with a first end (51 1 ) in fluid connection with siphon pipe (5) at a point lower than siphon point (531 ), a second end (512) in fluid connection with siphon pipe at siphon point, and a third end (513) opening into the rectangular weir. The said interconnected pipes are designed such that any fluid entering first end (51 1 ) will fall downwards through its dropper (514) to feed the ejector (515) and through the ejector to exit into the third end (513) and in so doing create a suction at the second end (512). A cup (44) is located at a lower end of said upper chamber (4), said cup comprising a receptacle with a top opening. A siphon break line (53) comprises an elongated pipe with an upper end (531 ) in fluid connection with said siphon pipe (5) at said siphon point (531 ) and a lower end (532) opening into and within said cup (44). After a period of the apparatus being in filtration mode, the said at least one filter membrane (31 ) becomes progressively less permeable at the said upstream side, thus causing the water level to rise in both the said feed cylinder (10) and the said siphon pipe (5) until the water starts flowing into the said first end (51 1 ), in turn causing the said ejector system (51 ) to expel all the air from within the said siphon pipe (5). This then initiates the "out-to-out" backwash mode, whereupon unfiltered water from the feed cylinder (10) cleans the said upstream side of the at least one filter membrane (31 ) and the lower chamber (2) before being sucked out via the siphon pipe (5). During this "out-to- out" backwash mode, the said unfiltered water level in the said feed cylinder (10) falls to the said feed outlet (12) level which results in the unfiltered water falling from the said feed inlet (1 1 ), thus inducing a stream of air bubbles to said inlet (21 ), said air bubbles enhancing cleaning of the said membranes. This continues until the unfiltered water level in the said feed cylinder (10) falls to a level that is lower than the level of said product water (42) in the upper chamber (4). When this happens, the said product water in the upper chamber (4) will flow downwards into the said lower chamber (2), so the direction of flow through the filter membranes (31 ) is reversed, and entrapped particles at the upstream end of the filter membranes (31 ) and lower chamber (2) are substantially removed, in what is known as an "in-to-out" backwash mode. This "in-to-out" backwash mode continues until the level of product water in the said upper chamber (4) falls to the said lower end (532) of the said siphon break line (53) whereupon air will be sucked into the said siphon break line (53), thus breaking the siphon and causing the apparatus to switch back to filtration mode. The apparatus is able to automatically switch between backwash mode and filtration mode in a repeatable fashion. The flow rate through the said filter membrane (31 ) during the backwash mode is at least twice the flow rate during the filtration mode. In a preferred embodiment, the diameter of the said siphon pipe (5) is larger than the diameter of the said interconnected pipes of the ejector system (51 ) and the diameter of the said elongated pipe of the siphon break line (53).

As is available in all the previous embodiments, and shown in Figures 1 and 2, there is provided a manual isolating valve (22), said manual isolating valve allowing control of manual backwash, especially useful for repeat enhanced backwashing, with or without the aid of air scouring and anti-fouling chemicals such as mild chlorine, acid and alkali.

The said manual isolating valve (22) could also be replaced with either a motorized or solenoid valve, to be used in conjunction with a timer or pressure differential switch to automatically induce backwashing according to adjustable and preset time or pressure differential.

Referring to Figure 7, there is shown a filter component for use in a water filtration apparatus comprising a mounting plate (3), said mounting plate sandwiched between an upstream and a downstream side of said water filtration apparatus, said mounting plate designed to be either irremovable (permanently welded) or removable from said water filtration apparatus in a repeatable fashion. A single or plurality of filter membranes (31 ) is located on said mounting plate, said filter membranes providing the filtering means between the said upstream and downstream sides. A ring shaped flexible rubber mounting piece (35) is located between each filter membrane (31 ) and the mounting plate (3), and is secured by a band clamp (36).

In all 4 embodiments, it should be noted that the filter membranes are not limited to a particular type but can be any of: microfiltration membranes, ultrafiltration membranes and nanofiltration membranes. The materials used in the construction of the water filter apparatus for all embodiments are extensive and can be a combination of, but are not limited to, polyvinyl chloride, high-density polyethylene, glass reinforced plastic, acrylonitrile butadiene styrene, stainless steel, carbon steel, other non-ferrous metals and concrete. Finally, in alLembodiments, the water filter can be either a gravity system or a pressurized system. This invention is not limited to filtration of drinking water but in fact of any other suitable fluids such as industrial fluids, waste water, and seawater.

In all four embodiments, the shape of the upper and lower chambers can be configured to suit the site. They can be made into any shape, including round, square, rectangular, and L-shaped. These versatile shapes also apply to the configuration of the common mounting plate and arrangements of the membranes.

The water filters described above may be operated with or without electricity. Obviously when air blower, motorized valve, timer, level/pressure switch or pump are incorporated, electricity is required. While several particularly preferred embodiments of the present invention have been described and illustrated, it should now be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are intended to embrace such changes, modifications, and areas of application that are within the spirit and scope of this invention.

Claims

1. An apparatus for water filtration with an automatic backwash cycle comprising:

a membrane water filter comprising an upper chamber (4), a lower chamber (2), and at least one filter membrane (31 ) separating said upper (4) and lower (2) chambers, said at least one filter membrane having an upstream side facing the said lower chamber (2) and a downstream side facing the said upper chamber (4), wherein during a filtration mode, unfiltered water is fed into said lower chamber (2) via an inlet (21 ) and passes via the said at least one filter membrane (31 ) into the said upper chamber (4) to become product water, thereafter exiting said upper chamber (4) via an exit pipe (42), said exit pipe located close to a top of said upper chamber (4);

a feed system (1) for feeding water to said membrane water filter comprising a substantially vertical feed cylinder (10) and having a feed inlet (11 ) at an intermediate point along the length of said feed cylinder for receiving said unfiltered water and a feed outlet (12) close to the bottom of said feed cylinder for expelling said unfiltered water, said feed outlet (12) in fluid communication with said inlet (21 );

a backwash system comprising:

a siphon pipe (5) with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber (2), said siphon pipe then rising to a siphon point (531 ) and then doubling back downwards and opening into a rectangular weir (61);

an ejector system (51) comprising a series of interconnected pipes with a first end (511 ) in fluid connection with said siphon pipe (5) at a point lower than said siphon point (531 ), a second end (512) in fluid connection with said siphon pipe (5) at said siphon point (531 ), and a third end (513) opening into said rectangular weir (61 ), said series of interconnected pipes designed such that any fluid entering said first end (511 ) will fall downwards and through the ejector to exit into said third end (513) and in so doing create a suction at the said second end (512);

a cup (44) located at a lower end of said upper chamber (4), said cup comprising a receptacle with a top opening;

a siphon break line (53) comprising an elongated pipe with an upper end (531 ) in fluid connection with said siphon pipe (5) at said siphon point

(531) and a lower end (532) opening into and within said cup (44)

whereby after a period of the apparatus being in filtration mode, the said at least one filter membrane (31) becomes progressively less permeable at the said upstream side, thus causing the water level to rise in both the said feed cylinder (10) and the said siphon pipe (5) until the water starts flowing into the said first end (511 ), in turn causing the said ejector system (51) to expel all the air from within the said siphon pipe (5), thus initiating the backwash mode, whereupon unfiltered water from the feed cylinder (10) cleans the said upstream side of the at least one filter membrane (31 ) and lower chamber (2) before being sucked out via the siphon pipe (5) until the unfiltered water level in the said feed cylinder (10) falls to a level that is lower than the level of said product water in the upper chamber (4), whereupon the said product water in the upper chamber (4) will flow downwards into the said lower chamber (2) and be sucked out by the said siphon pipe (5), until the level of product water in the said upper chamber (4) falls to the said lower end (532) of the said siphon break line (53) whereupon air will be sucked into the said siphon break line (53) thus breaking the siphon and causing the apparatus to switch back to filtration mode, said apparatus able to automatically start and terminate the said backwash mode in a repeatable fashion. When required, the enhanced backwash can be carried out through repeated backwashing and air- scouring with or without chemicals.

An apparatus for water filtration with an automatic backwash cycle according to claim 1 further comprising a feed tank (1 ) connected to the top of the said vertical feed cylinder (10) to store an additional volume of feed water.

An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims wherein the said siphon pipe (5) has a larger diameter than the said interconnected pipes of the ejector system (51).

An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims wherein the said siphon pipe (5) has a larger diameter than the said elongated pipe of the siphon break line (53).

An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims wherein, during the said backwash, the said unfiltered water level in the said feed cylinder (10) falls to the said feed outlet (12) level which results in the unfiltered water falling from the said feed inlet (11 ), thus inducing a stream of air bubbles to said inlet (21 ), said air bubbles enhancing cleaning of the said membranes.

An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims further comprising a manual or automated motorized isolating valve (23), said isolating valve allowing control of a desludging, controlled cross-flow and/or backwash.

An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims further comprising a manual isolating or automated motorized valve (22), said isolating valve allowing said ejector pipes to fill to start said siphon.

8. An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims wherein the said rectangular weir (61 ) allows fine tuning of the starting time of the backwash cycle.

9. An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims further comprising an air blower (80), said air blower can be either manually or automatically activated, said air blower able to introduce air bubbles into the lower chamber for scouring said filter membranes (31 ).

10. An apparatus for water filtration with an automatic backwash cycle comprising:

a feed system (1 ) for feeding water to said membrane water filter comprising an incoming feed line (10) in fluid connection with a hydro-pneumatic vessel (71 ) and subsequently to a feed outlet (12), a pressure switch (72) able to sense the pressure within said vessel (71 );

a drainage means comprising a drainage pipe (74) connected at one end (741 ) to a lower portion of said lower chamber (2) and the other end (742) draining out externally, and a motorized valve (73) for controlling the flow within said drainage pipe (74), said motorized valve (73) activated by said pressure switch (72) whereby after a period of the apparatus being in filtration mode, the said at least one filter membrane (31 ) becomes progressively less permeable at the said upstream side, causing the pressure in lower chamber (2) to increase progressively until it allows part of the incoming feed water to enter the said hydro- pneumatic vessel (71 ) until a predetermined pressure point is reached, causing the pressure switch (72) to activate the motorized valve (73), which then opens the drainage pipe (74) and initiates a backwash.

1 1 . An apparatus for water filtration with an automatic backwash cycle according to claim 10 wherein the said motorized valve (73) has a manual override which allows for manual control of backwashing.

12. An apparatus for water filtration with an automatic backwash cycle according to any of the preceding claims wherein the flow rate through the said at least one membrane (31 ) during the backwash mode is at least twice the flow rate during the filtration mode.

13. An apparatus for water filtration with an automatic backwash cycle comprising:

a lower chamber (2);

an upper chamber (4) located above said lower chamber (2), and in fluid communication with said lower chamber;

at least one connecting pipe (2c), said at least one connecting pipe establishing the said fluid communication between said upper chamber (4) and said lower chamber (2);

at least one filter membrane (31 ) located inside said lower chamber (2) and dividing said lower chamber into a top section (2b) and a bottom section (2a), each said section only fluid communicable to the other via said filter membrane (31 ), said at least one filter membrane having an upstream side facing said bottom section (2a) and a downstream side facing said top section (2b), wherein during a filtration mode, unfiltered water is fed into said bottom section (2a) via an inlet (21 ) and passes via the said at least one filter membrane (31 ) into the said top section (2b) to become product water, thereafter flowing upwards into said upper chamber via said at least one connecting pipe, and exiting said upper chamber (4) via an exit pipe (42), said exit pipe located close to a top of said upper chamber (4);

a feed system (1 ) for feeding water to said membrane water filter comprising a substantially vertical feed cylinder (10) and having a feed inlet (1 1 ) at an intermediate point along the length of said feed cylinder for receiving said unfiltered water and a feed outlet (12) close to the bottom of said feed cylinder for expelling said unfiltered water, said feed outlet (12) in fluid communication with said inlet (21);

a backwash system comprising:

a siphon pipe (5) with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber (2), said siphon pipe then rising to a siphon point (531) and then doubling back downwards and opening into a rectangular weir (61 );

an ejector system (51 ) comprising a series of interconnected pipes with a first end (511 ) in fluid connection with said siphon pipe (5) at a point lower than said siphon point (531 ), a second end (512) in fluid connection with said siphon pipe (5) at said siphon point (531 ), and a third end (513) opening into said rectangular weir (61 ), said series of interconnected pipes designed such that any fluid entering said first end (511 ) will fall downwards and exit through said third end (513) and in so doing create a suction at the said second end (512);

a siphon break line (53) comprising an elongated pipe with an upper end (531 ) in fluid connection with said siphon pipe (5) at said siphon point (531 ) and a lower end (532) opening into and within said cup (44) whereby after a period of the apparatus being in filtration mode, the said at least one filter membrane (31 ) becomes progressively less permeable at the said upstream side, thus causing the water level to rise in both the said feed cylinder (10) and the said siphon pipe (5) until the water starts flowing into the said first end (51 ), in turn causing the said ejector system (51) to expel all the air from within the said siphon pipe (5), thus initiating the backwash mode, whereupon unfiltered water from the feed cylinder (10) cleans the said upstream side of the at least one filter membrane (31 ) and lower chamber (2) before being sucked out via the siphon pipe (5) until the unfiltered water level in the said feed cylinder (10) falls to a level that is lower than the level of said product water in the upper chamber (4), whereupon the said product water in the upper chamber (4) will flow downwards into the said lower chamber (2) and be sucked out by the said siphon pipe (5), until the level of product water in the said upper chamber (4) falls to the said lower end (532) of the said siphon break line (53) whereupon air will be sucked into the said siphon break line (53) thus breaking the siphon and causing the apparatus to switch back to filtration mode, said apparatus able to automatically start and terminate the said backwash mode in a repeatable fashion. When required, the enhanced backwash can be carried out through repeated backwashing and air- scouring with or without chemicals.

An apparatus for water filtration with an automatic backwash cycle according to claim 13 further comprising a feed tank (14) connected to the top of the said vertical feed cylinder (10) to store an additional volume of feed water.

An apparatus for water filtration with an automatic backwash cycle according to any of claims 13 to 14 wherein the said siphon pipe (5) has a larger diameter than the said interconnected pipes of the ejector system (51).

16. An apparatus for water filtration with an automatic backwash cycle according to any of claims 13 to 15 wherein the said siphon pipe (5) has a larger diameter than the said elongated pipe of the siphon break line (53).

17. An apparatus for water filtration with an automatic backwash cycle according to any of claims 13 to 16 wherein, during the said backwash, the said unfiltered water level in the said feed cylinder (10) falls to the said feed outlet (12) level which results in the unfiltered water falling from the said feed inlet (11 ), thus inducing a stream of air bubbles to said inlet (21 ), said air bubbles enhancing cleaning of the said membranes.

18. An apparatus for water filtration with an automatic backwash cycle according to any of claims 13 to 7 further comprising a manual or automated motorized isolating valve (22), said isolating valve allowing said ejector pipes to fill to start said siphon.

19. An apparatus for water filtration with an automatic backwash cycle according to any of claims 13 to 18 wherein the said rectangular weir (61 ) allows fine tuning of the starting time of the backwash cycle.

20. An apparatus for water filtration with an automatic backwash cycle according to any of claims 13 to 19 further comprising an air blower (80), said air blower can be either manually or automatically activated, said air blower able to introduce air bubbles into the lower chamber for scouring said filter membranes (31 ).

21. A method of water filtration with an automatic backwash cycle comprising the steps of:

a. feeding unfiltered water from a feed inlet (1 ) into a substantially vertical feed cylinder (10) at an intermediate point along said feed cylinder; b. allowing said unfiltered water within said feed cylinder (10) to drain into a lower chamber (2) via a feed outlet (12);

c. filtering said unfiltered water from said lower chamber (2) through at least one filter membrane (31 ) into an upper chamber (4), in a filtration mode; d. allowing the level of unfiltered water in a siphon pipe (5) to rise as the said at least one filter membrane (31 ) becomes increasingly less permeable, with one end of said siphon pipe in fluid connection to a bottom end of said lower chamber (2), said siphon pipe then rising to a siphon point (531 ) and then doubling back downwards and opening into a rectangular weir (61 );

e. emptying any air within the said siphon pipe (5) via an ejector system (51 ), said ejector system comprising a series of interconnected pipes with a first end (511 ) in fluid connection with said siphon pipe (5) at a point lower than said siphon point (531 ), a second end (512) in fluid connection with said siphon pipe (5) at said siphon point (531), and a third end (513) opening into said rectangular weir (61 ), said series of interconnected pipes designed such that any water entering said first end (511 ) will fall downwards and exit through said third end (513) and in so doing create a suction at the said second end (512), said emptying triggered when said level of unfiltered water in said siphon pipe (5) reaches said first end (511 ); and

f. triggering a backwash cycle once the said level of unfiltered water in the siphon pipe (5) reaches said siphon point (531 ), whereby unfiltered water from the feed cylinder (10) cleans the said upstream side of the at least one filter membrane (31 ) and the lower chamber (2) before being sucked out via the siphon pipe (5) until the unfiltered water level in the said feed cylinder (10) falls to a level that is lower than the level of said product water in the upper chamber (4), whereupon the said product water in the upper chamber (4) will flow downwards into the said lower chamber (2) and be sucked out by the said siphon pipe (5); and g. breaking the siphon when water level, in said upper chamber falls below a lower end (532) of a siphon break line (53), said siphon break line comprising an elongated pipe with an upper end (531) in fluid connection with said siphon pipe (5) at said siphon point (531 ) and with said lower end (532) opening into and within a cup (44), said cup located at a lower end of said upper chamber (4), hence switching water filter back to said filtration mode.

22. A method of water filtration with an automatic backwash cycle according to claim 21 wherein the said siphon pipe (5) has a larger diameter than the said interconnected pipes of the ejector system (51).

23. A method of water filtration with an automatic backwash cycle according to any of claims 21 to 22 wherein the said siphon pipe (5) has a larger diameter than the said elongated pipe of the siphon break line (53).

24. A method of water filtration with an automatic backwash cycle according to any of claims 21 to 23 wherein, during the said backwash cycle, the said unfiltered water falls from the said feed inlet (11) to the bottom of the said feed cylinder (10), thus inducing a stream of air bubbles, said air bubbles enhancing cleaning of the said membranes.

25. A method of water filtration with an automatic backwash cycle according to any of claims 21 to 24 wherein said at least one filter membrane (31 ) is housed in a single common mounting plate (3), said mounting plate sandwiched between the lower chamber (2) and upper chamber (4).

26. A method of water filtration with an automatic backwash cycle according to any of claims 21 to 25 further comprising the step of introducing externally stored product water back into the upper chamber (4) during a planned or manual backwash cycle and adding a cleaning solution to the product water prior to this backwash cycle.

27. A method of water filtration with an automatic backwash cycle according to claim 26 further comprising the step of opening a manual or automated motorised isolating valve (23) to drain off the upstream water in the said lower chamber (2) and replacing it with said cleaning solution mixed water from the upper chamber (4), with the level of cleaning solution mixed water in the lower chamber (2) kept just below the top of the said lower chamber (2), and allowing the cleaning solution mixed water to soak through the membranes (31 ) for around 30 minutes, then rinsing the membranes (31 ) through feed-filtration-manual drain cycles until the water is substantially free of cleaning solution.

28. A method of water filtration with an automatic backwash cycle according to claim 27 wherein the said cleaning solution can be any of chlorine, alkali, or acid solutions.

29. A filter component for use in a water filtration apparatus comprising:

a mounting plate (3), said mounting plate sandwiched between an upstream and a downstream side of said water filtration apparatus, said mounting plate designed to be removable from said water filtration apparatus in a repeatable fashion;

at least one filter membrane (31 ) located on said mounting plate, said filter membrane providing the filtering means between the said upstream and downstream sides.

30. A filter component for use in a water filtration apparatus according to claim 29 wherein each of the said at least one filter membrane (31 ) is secured to the said mounting plate (3) by a locking mechanism (32).

31 . A filter component for use in a water filtration apparatus according to claim 29 further comprising a mounting piece (35) located between each said filter membrane (31 ) and said mounting plate (3), said mounting piece made of a substantially flexible material.

32. A filter component for use in a water filtration apparatus according to claim 31 wherein said flexible material includes rubber.

33. A filter component for use in a water filtration apparatus according to any of claims 29 or 32 wherein there is a single or plurality of said filter membranes (31 ) located on each said mounting plate (3).