WO2017007298A1

WO2017007298A1 - Means of creating a back pressure in an automatic backwash water filter

Info

Publication number: WO2017007298A1
Application number: PCT/MY2015/000051
Authority: WO
Inventors: Moon Tuck Mak
Original assignee: Moon Tuck Mak
Priority date: 2015-07-03
Filing date: 2015-07-03
Publication date: 2017-01-12

Abstract

A water filter with an automatic backwash that utilizes an artificially created back pressure to reduce the overall height of the water filter, and a water filter with a typical overall height of less than 3.5 meters for membrane filters and less than 5 meters for media filters, that incorporates a means of automatically creating, in a repeatable fashion, a backwash that removes trapped suspended solids from an upstream side of the filter.

Description

Means Of Creating A Back Pressure In An Automatic Backwash Water

Filter

FIELD OF INVENTION

The present invention relates generally to a means of creating a back pressure in an automatic backwash water filter.

BACKGROUND OF INVENTION

Today, hundreds of millions of people live in places where there is no access to adequately clean water. Industrial processes produce a huge amount of wastewater that requires treatment before it is suitable to be discharged into surface water systems. So there is a large demand for water filtration systems that cater to varied applications and requirements of size and purity of product water. What is also desired are water filtration systems that do not require much in terms of maintenance or service, so that they can be left in areas that have clean water deficiencies for a longer time without the need for skilled personnel or special tools. Another desirable feature in a water filtration system is its ability to function 24-hours daily without electricity. Many of these areas that are in need of clean water have either limited or no access to electrical power. Other desirable features are a small footprint, access to remote sites with minimum environmental impact and simplicity of installation with minimum engineering structures. Another important feature for water filtration systems is its ability to inhibit human or mechanical tampering or misuse.

One type of water filtration system that possesses many attributes mentioned in the previous paragraph is a gravity system that uses the potential energy of feed water from a higher elevation or pressure to drive the water through a filter of either a media composition such as sand, or a membrane type filter, and one of the techniques used to prolong the service life of these systems is to include an automatic backwashing function into the system, so that the filters are automatically cleaned by a backwash when there is enough suspended solids and other particles trapped at the upstream side of the filter.

Mak, in PCT Patent Application No. PCT/MY2012/000264, disclosed a water filter with such an automatic backwash function using a bell siphon and a system of inter-connecting pipes to initiate a siphon that creates the backwash function when a desired differential head is reached across the water filter due to suspended solids being trapped at the upstream side of the water filtration apparatus.

One downside in Mak's PCT Patent Application No. PCT/MY2012/000264 is the need for a large physical height difference between the product water outlet and the siphon level to create the desired differential head and initiate the siphon backwash. This results in an apparatus that cannot be used when the required minimum head room is unavailable or too costly to provide and therefore cannot be used in numerous applications such as within buildings including in temperate countries where the water filtration apparatus are required to be properly sheltered from damage during winters. Another downside of the physical height of Mak's PCT Patent Application No. PCT/MY2012/000264, (typically 4 meters for membrane filters to 6 meters for media filters), is the unnecessary difficulties for transportation, installations and applications in remote areas without proper skilled labor, safety equipment and often women are responsible for the installation, operations and maintenance of the water filtration apparatus.

What is needed in the art is a water filtration system that overcomes the above- mentioned physical height disadvantages. SUMMARY OF INVENTION

The present invention seeks to overcome the above-mentioned disadvantages by providing a water filtration apparatus with a typical overall height of less than 3.5 meters for membrane filters and less than 5 meters for media filters, that incorporates a means of automatically creating, in a repeatable fashion, a backwash that removes trapped suspended solids from an upstream side of the filter.

This invention thus relates to a low head room water filtration apparatus having an automatic backwash function, and more specifically to a water filtration apparatus that uses a column of trapped water to replicate within the water filtration apparatus, the desired differential head loss before initiating an automatic backwash. This invention relates to an apparatus for water filtration with an automatic and repeatable backwash function, capable of being in a filtration mode or a backwash mode. A feed pipe supplies raw, unfiltered water to the apparatus. A filter is provided in a lower chamber, dividing the lower chamber into an upstream and a downstream side, the filter adapted to allow mainly water to pass through and to restrict suspended solids from passing through by trapping said suspended solids at an upstream side.

This invention also relates to an apparatus for water filtration with an automatic and repeatable backwash function, comprising a feed pipe through which unfiltered water is supplied from an external source; a lower chamber having a feed inlet in fluid connection with said feed pipe; a filter located within said lower chamber and dividing said lower chamber into an upstream side and a downstream side, said filter adapted to allow mainly water to pass through and to restrict suspended solids from passing through; an upper chamber in fluid connection with said downstream side of said lower chamber, and a product outlet for expelling filtered water to an external use; a means of creating a backwash when a predetermined head differential has been reached across the said filter due to an amount of suspended solids trapped by the filter at its upstream side, including a siphon pipe having a lower end in fluid connection with a siphon outlet of said lower chamber, said siphon pipe rising up to a siphon level, where it is in fluid connection with an upper end of a siphon dropper, said siphon dropper dropping down to a lower end; a means of halting said backwash after a volume of water located in said upper chamber has been flushed through said filter; and a water trap located down-stream of the said siphon dropper, said water trap comprising a u-bend pipe containing a column of water, said column of water providing an increase in pressure along the said siphon pipe.

In a preferred embodiment of the present invention, the means of creating a backwash is a siphon bell, and further includes: a sealed casing having a first top opening in fluid connection with said lower end of said siphon dropper, a second top opening, and a bottom opening; a bell located within and at a bottom end of said sealed casing having an open bottom that encloses said bottom opening, a top opening, and at least one bell entry opening at a bottom section which allows fluid communication between said bell and said sealed casing; a snorkel comprising an inverted U-shaped pipe with a higher end being in fluid connection with said top opening of said bell, and a lower end being in fluid communication with said sealed casing; a water trap comprising a u- shaped pipe with a higher end and a lower end; a standpipe comprising a vertical pipe with a lower end in fluid connection with said higher end of the water trap, said standpipe protruding through said bottom opening of said sealed casing, into said bell, such that a higher end of the standpipe reaches a height that is higher than said lower end of said snorkel; and a drain pipe in fluid connection with said lower end of water trap.

In another preferred embodiment of the present invention, the means of creating a backwash is an air scourer, and further includes a means of generating air at said upstream side of said filter.

This invention also relates to an apparatus for water filtration with an automatic and repeatable backwash function wherein the means of halting the backwash comprises: a siphon break line having a higher end in fluid connection with an opening of said siphon pipe at said siphon level and a lower end protruding into said upper chamber; and a cup located within said upper chamber, and a volume of said cup immersing said lower end of said siphon break line, and said lower end located higher than a bottom of said cup. In another preferred embodiment of the present invention, the filter is a membrane filter, with the total height of the apparatus being less than 3.5 meters.

In another preferred embodiment of the present invention, the filter is a media filter, with the total height of the apparatus being less than 5 meters.

This invention further relates to a means of creating a back pressure in an automatic backwash water filter comprising a water trap located down-stream of a siphon dropper of said water filter, said water trap comprising a u-bend pipe containing a trapped column of water, said column of water providing an increase in pressure along a siphon pipe of said water filter. In all the above embodiments, there may be provided a manual means of starting the backwash. This comprises a manual bypass pipe forming a fluid connection between a downstream side of the filter and the siphon dropper and a manual bypass valve to allow manual opening and closing of said fluid connection. This manual means of starting the backwash is useful when it is desired for the operator to manually start the backwash at will.

The gravity feed used in this invention produces a low pressure at the filters, which results in suspended solids embedding to a lesser degree on the filters. This allows more thorough removal of trapped suspended solids from the filters during the backwash mode. This ultimately results in less fouling of the filters.

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 water filtration apparatus using a media filter with lower and upper chambers in a split configuration and a siphon bell backwash means in a first embodiment of this invention. Figure 2 shows a cross-sectional view of a water filtration apparatus using a membrane filter with lower and upper chambers in a split configuration and a siphon bell backwash means in a second embodiment of this invention.

Figure 3 shows a cross-sectional view of a water filtration apparatus using a media filter with lower and upper chambers in a tiered configuration and a siphon bell backwash means in a third embodiment of this invention.

Figure 4 shows a cross-sectional view of a water filtration apparatus using a membrane filter with lower and upper chambers in a tiered configuration and a siphon bell backwash means in a fourth embodiment of this invention.

Figure 5 shows a cross-sectional view of a water filtration apparatus using a media filter with lower and upper chambers in a split configuration and an air scourer backwash means in a fifth embodiment of this invention.

Figure 6 shows a cross-sectional view of a water filtration apparatus using a membrane filter with lower and upper chambers in a split configuration and an air scourer backwash means in a sixth embodiment of this invention. Figure 7 shows a cross-sectional view of a water filtration apparatus using a media filter with lower and upper chambers in a tiered configuration and an air scourer backwash means in a seventh embodiment of this invention.

Figure 8 shows a cross-sectional view of a water filtration apparatus using a membrane filter with lower and upper chambers in a tiered configuration and an air scourer backwash means in an eighth embodiment of this invention.

DETAILED DESCRIPTION OF INVENTION List of elements

feed pipe (12)

lower chamber (20)

feed inlet (212)

product opening (214)

siphon outlet (216)

upstream side (21 )

downstream side (22)

filter (30)

interconnecting pipe (40)

upper chamber (50)

bottom opening (52)

product outlet (54)

outlet pipe (56)

break line opening (58)

backwash creating means (60) siphon bell (62)

air scourer (64)

nozzles (641 )

siphon pipe (610)

siphon level (61 1 )

lower end of siphon pipe (612) siphon dropper (615)

lower end of siphon dropper (617) backwash halting means (70) siphon break line (710)

higher end of siphon break line (71 1 ) lower end of siphon break line (712) cup (720)

U-bend pipe (80) It should be noted that the following detailed description is directed to a water filter with automatic backwash that utilizes an artificially created back pressure to reduce the physical height of the water filter 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 Figures 1 through 8, there is shown various embodiments of an apparatus for water filtration with an automatic and repeatable backwash function, capable of being in a filtration mode or a backwash mode, with a lower chamber (20) and an upper chamber (50). Unfiltered feed water is supplied through a feed pipe (12). The lower chamber (20) is provided with a feed inlet (212) to which the feed pipe (12) is connected, such that the unfiltered water enters the lower chamber (20) via this feed inlet (212). The lower chamber is also provided with a product opening (214). A filter (30) is placed in the lower chamber (20) between the feed inlet (212) and the product opening (214), so that the filter (30) divides the lower chamber (20) into an upstream (before filter) side (21 ) and a downstream (after filter) side (22). The said filter (30) is adapted to allow mainly water to pass through and to restrict suspended solids from passing through. The product opening (214) of the lower chamber is in fluid communication with a bottom opening (52) of an upper chamber (50). The upper chamber (50) has a product outlet (54) for expelling filtered water via an outlet pipe (56) to an external use. During a filtration mode, unfiltered water passes through the feed pipe (12) into the upstream side (21 ) of the lower chamber, where suspended solids contained in the unfiltered water is filtered by the filter (30) and filtered water passes into the downstream side (22) of the lower chamber, and subsequently into the upper chamber (50). There, it is expelled via the product outlet (54) as product water for an external use.

Still referring to Figures 1 through 8, there is also shown a backwash creating means (60). This is a means of creating, automatically, a backwash when a predetermined differential head has been reached due to the amount of suspended solids trapped by the filter (30) at its upstream side, so that filtered water accumulated in the upper chamber (50) flows back through the filter from the downstream (22) to the upstream (21 ) side, and in this reversal of flow, removes the suspended solids from the filter upstream side. This backwash creating means (60) comprises: a siphon pipe (610) having a lower end (612) in fluid connection with an upstream side of the filter via a siphon outlet (216) located on the lower chamber (20), the siphon pipe (610) rising up to a siphon level (61 1 ) where the pipe becomes horizontal, after which the pipe bends back down where it becomes a siphon dropper (615), said siphon dropper dropping down to a lower end (617). Mak, in PCT Patent Application No. PCT/MY2012/000264, discloses a water filtration apparatus that is identical up to this point. In the present invention, there is further provided a U-bend pipe (80) connected to the lower end (617) of the siphon dropper (615). This U-bend pipe (80) initially contains a trapped column of water. As suspended solids get progressively trapped at the upstream side (21 ) of the filter (30), the pressure across the filter (30) builds up, thus driving water up the siphon pipe (610). As this water rises up the siphon pipe (610), a column of air in the siphon dropper (615) is compressed, because of the said column of water provided in the U-bend (80). It is this compression of air in the siphon dropper (615) that creates the backpressure, thus lowering the physical head needed for the siphon level (61 1 ) in order to instigate the siphon action for backwash. As the air is compressed even further, the said trapped column of water is progressively displaced from the U-bend (80).

There are two established ways that a backwash can be created: siphon bell (62) and air scourer (64). The siphon bell (62) has been described in Mak's PCT Patent Application No. PCT/MY2012/000264. The air scourer (64) is a method that uses a volume of air or other gas, injected via nozzles (641 ) located at the upstream side (21 ) of the filter (30), which causes a siphon to be instigated along the siphon pipe (610), thus creating a backwash. The said volume of air or other gas entering the upstream side (21 ) of the lower chamber displaces water contained within, and pushes the water into the siphon pipe (610) and over the siphon level (61 1 ). This said flow of water over the siphon level (6 1 ) instigates a siphon action for backwash. The said injection of this volume of air or other gas may be controlled by anv of: a pressure sensor that initiates the air scourer (64) once a predetermined pressure has been detected: a level sensor that initiates the air scourer (64) once the said trapped volume of water in the U-bend (80) reaches a predetermined level: or a timer that initiates the air scourer (64) at predetermined time intervals.

Still referring to Figures 1 through 8, there is shown a backwash halting means (70), which is a means of halting, automatically, said backwash, comprising: a siphon break line (710) having a higher end (71 1 ) in fluid connection with an opening of the siphon pipe (610) at the siphon level (61 1 ) and a lower end (712) protruding into the upper chamber (50) via a break line opening (58) of the upper chamber; a cup (720) located within said upper chamber (50), with the lower end (712) of the siphon break line being immersed into the cup (720), but said lower end (7 2) located higher than a bottom of said cup (720).

Figures 1 through 4 show embodiments where the backwash creating means is the siphon bell (62). In these embodiments, the said U-bend pipe (80) is located between the lower end (617) of the siphon dropper (615) and the siphon bell (62) inlet, and forms a contiguous fluid channel in between.

In Figure 1 and 2, there is shown a split tank embodiment, whereby the lower chamber (20) and upper chamber (50) are split some distance from each other and connected by an interconnecting pipe (40). In Figure 3 and 4, there is shown embodiments where the upper chamber (50) is stacked on top of the lower chamber (20), which is known as a tiered tank embodiment. In Figure 3, because the media filter requires the upstream side (21 ) of the filter to be above the downstream side (22), there is provided several interconnecting pipes (40) located within the lower chamber (20), and connecting the downstream side (22) of the lower chamber to the upper chamber (50). Figures 5 through 8 show embodiments where the backwash creating means is the air scourer (64). The air scourer (64) is a method that uses a volume of air or other gas, injected via nozzles (641 ) located at the upstream side (21 ) of the filter (30), which causes a siphon to be instigated along the siphon pipe (610), thus creating a backwash. In these embodiments, the said U-bend pipe (80) is joined to the lower end (617) of the siphon dropper (615) at one end, and is open at the other end, and thus forms a contiguous fluid channel between the siphon dropper (615) and an outside atmosphere. In Figure 5, there is shown a manual means of starting the backwash comprising a manual bypass pipe (90) forming a fluid connection between the upstream side (21 ) of the lower chamber (20) and the siphon dropper (615) and a manual bypass valve (92) to allow manual opening and closing of said fluid connection.

In all the above embodiments, the water flow rate through the filter (30) during the backwash mode is at least twice that during the filtration mode.

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 scope of the invention. Accordingly, the following claims are intended to embrace such changes, modifications, and areas of application that are within the scope of this invention.

Claims

1 . An apparatus for water filtration with an automatic and repeatable backwash function, comprising

a feed pipe (12) through which unfiltered water is supplied from an external source;

a lower chamber (20) having a feed inlet (212) in fluid connection with said feed pipe (12);

a filter (30) located within said lower chamber and dividing said lower chamber into an upstream side (21 ) and a downstream side (22), said filter adapted to allow mainly water to pass through and to restrict suspended solids from passing through;

an upper chamber (50) in fluid connection with said downstream side (22) of said lower chamber (20), and a product outlet (54) for expelling filtered water to an external use;

a means of creating a backwash (60) when a predetermined head differential has been reached across the said filter (30) due to an amount of suspended solids trapped by the filter (30) at its upstream side, including a siphon pipe (610) having a lower end (612) in fluid connection with a siphon outlet (216) of said lower chamber (20), said siphon pipe rising up to a siphon level (61 1 ), where it is in fluid connection with an upper end of a siphon dropper (615), said siphon dropper dropping down to a lower end (617) ;

a means of halting said backwash (70) after a volume of water located in said upper chamber (50) has been flushed through said filter

(30); and

a water trap (80) located down-stream of the said siphon dropper (615), said water trap comprising a u-bend pipe containing a trapped column of water, said column of water replicating a portion of the differential head between said product outlet (54) and said siphon level

(61 1 ). An apparatus for water filtration with an automatic and repeatable backwash function in accordance with claim 1 , wherein the said means of creating a backwash (60) further includes:

a sealed casing (620) having a first top opening (621) in fluid connection with said lower end (617) of said siphon dropper (615), a second top opening (623), and a bottom opening (622);

a bell (635) located within and at a bottom end of said sealed casing (620) having an open bottom that encloses said bottom opening (622), a top opening (636), and at least one bell entry opening (645) at a bottom section which allows fluid communication between said bell (635) and said sealed casing (620);

a snorkel (625) comprising an inverted U-shaped pipe with a higher end (626) being in fluid connection with said top opening (636) of said bell, and a lower end (627) being in fluid communication with said sealed casing (620);

a water trap (660) comprising a u-shaped pipe with a higher end (661) and a lower end (662);

a standpipe (640) comprising a vertical pipe with a lower end (641) in fluid connection with said higher end (661) of the water trap, said standpipe protruding through said bottom opening (622) of said sealed casing, into said bell (635), such that a higher end (642) of the standpipe (640) reaches a height that is higher than said lower end (627) of said snorkel (625); and

a drain pipe (670) in fluid connection with said lower end (662) of water trap.

An apparatus for water filtration with an automatic and repeatable backwash function in accordance with claim 1 , wherein the said means of halting a backwash (70) comprises:

a siphon break line (710) having a higher end (711) in fluid connection with an opening of said siphon pipe (610) at said siphon level (611) and a lower end (712) protruding into said upper chamber (50); and a cup (720) located within said upper chamber, and a volume of said cup immersing said lower end (712) of said siphon break line (710), and said lower end (712) located higher than a bottom of said cup (720).

An apparatus for water filtration with an automatic and repeatable backwash function in accordance with claim 1 , wherein the said means of creating a backwash (60) further includes a means of introducing a volume of air at said upstream side of said filter (30).

An apparatus for water filtration with an automatic and repeatable backwash function in accordance with claim , wherein the said filter (30) is a membrane filter.

An apparatus for water filtration with an automatic and repeatable backwash function in accordance with claim 5, wherein the said total height of the apparatus is less than 3.5 meters.

An apparatus for water filtration with an automatic and repeatable backwash function in accordance with claim 1 , wherein the said filter (30) is a media filter.

An apparatus for water filtration with an automatic and repeatable backwash function in accordance with claim 7, wherein the said total height of the apparatus is less than 5 meters.

A means of creating a back pressure in an automatic backwash water filter comprising a water trap (80) located down-stream of a siphon dropper (615) of said water filter, said water trap comprising a u-bend pipe containing a trapped column of water, said column of water providing an increase in pressure along a siphon pipe (610) of said water filter.