GB2335150A - Filter apparatus with reverse flushing - Google Patents

Abstract

A filter apparatus for domestic waste water recycling is periodically cleaned out by reverse flushing with the filtered water. The flushing operation may be actuated by a float 10. Water from washing dishes enters at inlet 3, passes through cylindrical filter element 4 into tank 5, and out through first outlet port 12 to be used for flushing toilets. As filtered water builds up in tank 5, float 10 is lifted above the position shown, bringing sets of apertures 8,11 in the base unit into engagement with each other. Filtered water in the tank 5 then flows out into drain 2 flushing out the residue which has built up on the filter element. In a second embodiment (Figs 7-14) float actuated valves and siphons initiate flushing periodically and also if the filter element gets blocked. The filter apparatus may be housed in a rodding or inspection chamber of a domestic water system.

Description

A FILTER 2335150 The present invention relates to a filter for filtering

fluid and particularly (but not exclusively) to a water filter for use in recycling domestic water.

It is often necessary or desirable to recycle water. There are ecological reasons to encourage domestic users of water to be frugal with their use of water or to find ways to use water more than once. In dry periods, for example during long hot summers, it may become necessary for restrictions to be imposed on water use as reservoir levels drop. For example, the use of hose pipes may be banned and in extreme water shortage conditions, an individual's water supply may be cut off resulting in households having to use standpipes.

The present invention seeks to reduce water consumption by providing improved water filters and methods for recycling soiled water. In one aspect, it is based on a recognition that water chambers which to date have only been used as rodding and inspection points are a convenient location for exploiting multi-purpose water filters.

Thus viewed from one aspect the present invention provides a fluid recycling apparatus comprising:

a filter having an inlet port through which unfiltered fluid may enter the system; an outlet port from which filtered fluid may exit the system; first filtering means for filtering fluid entering via the inlet port leaving filter residue in the first filtering means; fluid retaining means for retaining filtered fluid; a second outlet port through which filter residue may be removed from the system; and flushing means for periodically causing the fluid in the fluid retaining means to flow out of the second outlet port thereby flushing filter residue from the system.

-2 The present invention is particularly useful for filtering kitchen waste water (for example water which has been used to wash dishes). The filtered water may be used to flush toilets, such water not having to have a high level of purity but merely needing to be relatively clean. The flushing of toilets may use a large amount of water (typically two gallons per flush) and in a household of, for example, four people a significantly large amount of water may be used during the course of the day. By allowing water which has already been used in a domestic situation to be re-used for flushing toilets, the present invention represents a significant saving on water consumption. Whilst domestic usage is envisaged as the primary application of the present invention, industrial applications are equally suitable.

In a first embodiment of the invention, the flushing means advantageously comprises a first base unit having a plurality of first apertures, each aperture having an open position and a closed position. The second outlet port may be conveniently connected to the first base unit. When the apertures are in the open position, the fluid retaining means is connected via the second outlet port to a waste outlet. Thus when the apertures are in a open position, fluid retained in the fluid retaining means may flow out of the filter via the first apertures and into the waste outlet. During this process, the fluid will flush out the filter residue remaining in the first filtering means. The waste outlet may be for example be a sewage main.

Conveniently, the apparatus of the invention further comprises a second base unit engageable with the first base unit and having a plurality of second apertures corresponding to the first apertures in the first base unit. The first and second base units may form a composite base unit which has a first position in which there is no overlap between first and second apertures and a second position in which at least some of the first and second apertures are aligned at least partially with one another.

When the composite base unit is in the first position, no water may exit the filter system into the waste outlet. However when the composite base unit is in the second position water may exit the system. Advantageously the composite base unit is spring loaded.

Advantageously the second base unit forms part of an inner filter unit having a top portion (eg a float) adapted to float above the level of fluid within the fluid retaining means. As the level of fluid within the fluid retaining means rises, the top portion will also rise causing the second base unit to move relative to the first base unit bringing the first apertures into alignment with the second apertures. Thus once the fluid level within the fluid containing means has reached a certain level, the composite base unit will move to its open position causing fluid in the fluid retaining means to flow out of the filter system and in doing so flush out filter residue. As the water level falls, the composite base unit will move to its closed position stopping the flow of fluid from the system and allowing the level of fluid to build up once again. The apparatus therefore periodically flushes itself in order to prevent build up of filter residue.

In a second embodiment of the invention, the base unit comprises a valve seat which is capable of receiving a float activated valve. Preferably the valve is attached to a syphonic assembly capable of drawing fluid from a fluid retaining means. Preferably the valve may be activated by floating means within the first fluid retaining means. Particularly preferably the valve-activating means may be activated by floating means within a second fluid retaining means which fills when the filters and/or inlet pipes are blocked.

Preferably the apparatus of the invention further comprises an internal chamber defining a non-flushable fluid retaining volume between the fluid retaining means and the filtering means.

The components of the fluid recycling apparatus may be made of any suitable material but conveniently it is made from an unplasticised PVC or polypropylene or similar material. 0rings and seals may be used to seal adjacent components and may be made from any suitable material such as styrene butadine rubber (SPR) Certain parts may be fitted together with quick release couplings such as bayonets or twist-lock type fastenings. This allows easy access to the base units and waste pipes for rodding.

: The filter element may be formed from, for example, polypropylene and stainless steel. Alternatively gauze or fine mesh could be used.

The fluid recycling apparatus may have a plurality of inlet ports and outlet ports. This allows the filter apparatus to be easily connected into any domestic water system, or alternatively to be connected into more than one water system whereby to serve as a filter for more than one water system.

Preferably, the apparatus comprises one or more further fluid retaining means (eg tanks) which increase the storage capacity of the apparatus of the invention. This may be necessary where the desired location of the apparatus prevents the use of a large primary fluid retaining means.

According to a second aspect of the present invention there is provided a method for recycling domestic water using the fluid recycling apparatus of the first aspect of the present invention.

Domestic water chambers are presently used as rodding and inspection points. The present invention is based on the recognition that filtering, rodding and inspection may be simultaneously performed in existing domestic water chambers by a single multi-purpose apparatus. Thus in a further aspect, the invention provides the use of water filters in domestic water chambers for rodding and inspection. By allowing filtering, rodding and inspection to be straightforwardly performed by a single apparatus, the use according to the present invention represents an advantage over existing methods which make use of separate "grey water" filtration units.

The invention will now be further described by way of example only with reference to the accompanying drawings in which:- Figure 1 is a schematic representation of a first embodiment of the invention showing a composite base unit in a closed position; Figure 2 is a schematic representation of the apparatus of Figure 1 showing a composite base unit in an open position; Figure 3 is a schematic representation of the abovementioned embodiment of the invention having a second tank positionable below the base unit; Figure 4 is a schematic representation of the first filtering means showing the float; Figures 4a and 4b are cross sectional representations of the filtering means and the float of Figure 4; Figure 4c is a detailed schematic representation showing engagement of the float with the filtering means; Figures 5a, 5b, 5c and 5d are schematic representations of the base unit of Figure 3; Figures 6a - 6f are schematic representations of the second base unit of the apparatus of Figure 3; Figure 7 is a skeletal outline of a second embodiment of the invention; Figure 8 illustrates the static internal parts of the second embodiment; Figure 9 illustrates the moving parts of the second embodiment of the invention; Figure 10 illustrates the valve lifter/syphonic assembly of the second embodiment; Figure 11 illustrates the position of the floats along AA and BB in Figure 9; Figures 12-14 represent the second embodiment is use; and Figure 15 represents an apparatus capable of retaining a volume of water after flushing.

Figure 1 illustrates a first embodiment of the invention 1. The apparatus is adapted to be installed below ground level and to interact with an existing sewage main 2. The filter apparatus comprises an inlet port 3 through which fluid to be filtered enters the first filtering means 4 which in this embodiment has a filtering surface formed from a mesh adapted to filter out impurities of the type typically found in kitchen waste water. The first filtering means comprises a plurality of ports 3 which may serve as both inlet ports for unfiltered fluid and outlet ports for filtered fluid. The filtered fluid enters a f luid retaining means 5 in the form of a tank by passing through the filtering surface of the first filtering means 4.

The apparatus of Figure 1 further comprises a composite base filter unit 6 comprising a first base unit 7 having a plurality of first apertures 8 formed therein. The f irst filtering means 4 is sealingly connected to the base of the unit 6. The composite base unit further comprises a second base unit 34 which is connected to a float 10 and which comprises a plurality of second apertures 11 corresponding to the first apertures 8 in the first base unit. The float 10 is formed from a material which is buoyant.

The position of the first and second base portions in Figure 1 is such that the apertures 8 and 11 do not overlap with one another (ie the closed position of the composite base unit). In this position, water entering the system is filtered by first filtering means 4 and the fluid retaining means 5. The water exits the system by first outlet port 12. Gradually the level of water within the system will rise until the level of water hits the float 10 as shown in Figure 2. As the water rises above this level, the water will push the float higher.

This in turn will cause the second base unit to move relative to the first base unit bringing the second apertures 11 into alignment with the first apertures 8. This will bring the second base unit into its second position as shown in Figure 2 which is the open position. In this position, the fluid contained within the fluid retaining means 5 will flow out of the filter system 1 via the apertures 8 and 11. In doing so, the water will flush out impurities 21 and deposit these impurities in the sewage mains 2. The flushing of the system continues until the float has moved a sufficient distance to bring the second base unit back into its closed position. The flushing of the system will therefore occur periodically in order to reduce the chances of the system becoming blocked through impurities.

In Figure 3, the apparatus 30 further comprises a second tank 32 positioned below the sewage main 2. This arrangement may be advantageous in that more water may be stored in the apparatus 30 without having a tank protruding above ground level. The second tank 32 is sealingly connected to the composite base unit 6 thus preventing filtered fluid contained within the second tank 32 from becoming contaminated by waste passing through the sewage mains 2.

In the apparatus described hereinbefore, the base unit 34 is attachable to and is formed as a raised shoulder around the circumference of the base unit 7. Base unit 34 is shown in more detail in Figures 6a to 6d and comprises a plurality of apertures 11 which are substantially equidistant from one another. Base unit 34 further comprises lugs 36 (shown in more detail in Figures 6e and 6f). The lugs may be used to attach filtering means 4 to second base unit 34. Springs may be inserted to allow movement between the filter element 4 and the second base unit 34.

Referring to Figures 6a - 6f, aperture 62 formed within second base unit 34 is the inner access point through which rodding of the first base unit 7 and the sewage main may be carried out. Cover 100 is removably sealable to the base unit in order to allow rodding to occur. The second base unit further comprises ports 64 which allow entry and exit of filtered fluid to and from the fluid retaining means and the secondary tank 32.

With regard to Figure 4, as fluid enters fluid retaining means 5 it hits the float 10 which causes the unit to rise. This brings the apertures 8 and 11 into alignment. Trapped debris is then carried through the ports and into the composite base unit 6 to be carried away in the sewage mains.

Figures 4a to 4c show in more detail the filtering means 4 shown in Figures 1 and 3. The filtering surface 40 of filtering means 4 comprises a mesh. The filtering means 4 is substantially cylindrical, although in other embodiments it could have a different cross sectional shape. Float 10 is moveable and may be initially positioned at any predetermined point along the length of filtering means 4 thus controlling the height and therefore capacity of fluid retaining means 5. This in turn will control the frequency of flushes since the system is arranged to flush once the fluid retaining means 5 is full. Furthermore, unfiltered fluid may pass above float 10.

Referring to Figure 4c, there is shown in detail one way in which the float 10 is connected to the filter element 4. A ratchet mechanism 400 comprises one or more teeth engageable with teeth 410 formed in the filter element 4. A seal 420 ensures sealing contact between the filter element 4 and float 10.

In figures 5a to 5d, the composite base unit 6 is shown in more detail. The base unit 6 comprises two transfer ports 62, 64 which allow flow of filtered fluid from fluid retaining means 5 into a second tank 32. They further allow the exit of filter fluid from the second tank 32. A submersible pump is used to pump the fluid from the lower chamber through the transfer ports 62 or 64. The pump may be housed in the second tank 32. It may have a delivery pipe which passes through either port 62 or port 64 leaving the other port 62 or 64 unobstructed to allow the ingress of filtered fluid from the fluid containing means 5.

The walls of the fluid retaining means 5 and the second tank 32 may be ribbed circumferentially. This provides added strength. In addition the ribbing may serve as a guide to allow the fluid retaining means 5 to be cut to a desired size appropriate for a particular location.

If the system is used as shown in Figures 1 and 2 without a second tank 32, a pump may be housed in the fluid retaining means 5. The pump is preferably powered by a 12 volt DC supply supplied by a suitable transformer. The pump may be switched on and off by either movement of the float 10 or by switches. Equally tank 32 may be provided with a submersible pump for transfer of fluid.

Figure 7 illustrates a second embodiment of the invention in skeletal outline. Thus, the apparatus comprises a base unit (A) adapted to couple with waste pipes to allow waste to pass into the sewage mains. Primary fluid retaining means (B) couples with the base unit (A) and is capable of retaining filtered fluid or "grey water". Unfiltered "grey water" may enter the retaining means via the pipes (N) (see Figure 8) from for example household waste pipes. The filter system (not shown in Figure 7) is housed within the primary retaining means which also allows access to the base unit (A) and sewage mains for rodding and inspection. Secondary fluid retaining means (C) and (E) may be attached when required. The apparatus is conveniently provided with an access cover (D).

A detailed illustration of the internal structure of the primary retaining means (B) is given in Figures 8 and 9. Figure 8 shows non- moving parts only. Thus, upper (G) and lower (I) filters are provided in the form of substantially circular meshes at the ends of a housing (H). Any number of other filters may be provided between (G) and (I) and the grade of each filter may be varied. The filter G is provided with a non-return diaphragm which allows filtered fluid to pass from the housing (H) but prevents it returning. The housing is coupled by a coupling member (J) to the inlet/transfer pipe (N). Although not shown, the inlet/transfer pipe has a gauze strainer fitted above the inlet to prevent debris entering the filter blocked reservoir. Base cover (K) covers the base unit (A) whilst mounting parts (J), (H) and (N). It also acts as a retaining means for heavy debris before flushing into base unit (A). Coupling member (L) is required when a secondary retaining means (C) is used.

A primary assembly plate (M) fixes parts (K), (J) and (H) and allows the primary retaining means and its internal parts (with the exception of L) to be removed as one to permit access to the base unit (A) and waste pipes for rodding. The primary retaining means also contains a filter blocked reservoir (F) which fills with fluid if the pipes (N) become blocked. This actuates the valve lifter/syphon means (S) whose operation is described hereinafter.

Figure 9 shows the moveable parts of the internal structure of the primary containment means. Thus, valve lifter/syphonic means (S) is a composite structure (see Figure 10) of a fixed syphonic piston 1, a pick- up bend 2, diaphragm 3, ported piston seal 4, cylinder 5, piston seal retaining cap 6, valve connecting rod 7 and valve head 8. The valve lifter/syphonic means may also be provided with an adjuster bush which serves as a stop for periodic lifter plate (R) and determines the frequency of flushing of the filter unit (see below). The base cover (K) serves as the valve seat for the valve lifter/syphon means (S).

Lifter spheres/floats (Q) serve to lift filter blocked lifter plate (P) and periodic lifter plate (R) when the fluid level rises in the respective chambers to the appropriate level. The general position of the floats along lines A, A and B, B respectively is shown in Figure 12. The use of this 1 1 embodiment of the invention will now be described with reference to Figures 12 to 14.

In Figure 12, unfiltered "grey water" enters the apparatus and passes through the filter assembly. It fills the lower and primary fluid retaining means (B and E) before exiting through the upper ports (50). With reference to Figure 13, whilst the apparatus fills and the fluid is filtered, the floats activate the periodic lifter plate (R) to remove the valve from its seat in order to flush debris into the base unit (A) which is coupled to a waste pipe. The frequency of flushing is determined by the position of a bush. The arrangement of the U-shaped pickup bend allows the periodic lifter plate to move without disturbing the filter- blocked lifter plate (P) but still dislocating the valve from its seat.

When the filter assembly blocks and fluid backsup the transfer pipes (Figure 14), the filter blocked reservoir (F) is filled with fluid. This causes the floats to lift the filter blocked lifter plate (P) allowing the syphonic piston 1 of the valve means (S) to rise and displace the valve head 8 from its seat. This ensures that the debris blocking the filters and transfer pipes is flushed into the base unit. Once this is completed and the filter block reservoir has emptied, the valve will return to its seat and filtration will resume.

As the syphonic piston 1 rises, a vacuum is created in the lower part of the valve/lifter means 5 below diaphragm 3 which draws fluid from the filter blocked reservoir (F) via part 1 of the valve means (S). Fluid then enters the valve cylinder 5, passing between the diaphragm 3 and finally exiting via the cylinder port 4 located below the cap 6.

In the embodiments of the invention previously described, it is desirable that the fluid retaining means is capable of retaining at least a portion of the fluid it contains. Figure 15 illustrates an apparatus capable of achieving the desired effect. Thus an internal chamber 60 may be provided within the walls of the filtering means which serves to define an enclosed -12 volume 61 capable of retaining water even after periodic flushing.

Claims (11)

1. Claims

   A fluid recycling apparatus comprising: a filter having an inlet port through which unfiltered fluid may enter the system; an outlet port from which filtered fluid may exit the system; first filtering means for filtering fluid entering via the inlet port leaving filter residue in the first filtering means; first fluid retaining means for retaining filtered fluid; a second outlet port through which filter residue may be removed from the system; and flushing means for periodically causing the fluid in the fluid retaining means to flow out of the second outlet port thereby flushing filter residue from the system.
2. 2. An apparatus as claimed in claim 1 comprising a second fluid retaining means.
3. 3. An apparatus as claimed in claim 1 or 2 comprising an internal chamber defining a non-flushable fluid retaining volume between the first fluid retaining means and the filtering means.
4. 4. An apparatus as claimed in any preceding claim wherein said flushing means is activated by first floating means capable of floating on the surface of the fluid within the fluid retaining means.
5. 5. An apparatus as claimed in claim 4 wherein said flushing means comprises a first base unit having a plurality of first apertures and said first floating means is connected to a second base unit comprising a plurality of second apertures whereby movement of said first floating means to a 14- predetermined position brings said second base unit into alignment with said first base unit so that the first and second apertures thereof define an open path between said first fluid retaining means and said second outlet port.
6. 6. An apparatus as claimed in claim 4 wherein said flushing means comprises a periodic lifter plate capable of being lifted by said first floating means as said first fluid retaining means fills with fluid.
7. 7. An apparatus as claimed in claim 4 or 6 wherein said flushing means comprises a lifter plate capable of being lifted by a second floating means, wherein said second floating means is located within a second fluid retaining means which is capable of filling with water when said filtering means or said inlet pipe is blocked with impurities.
8. 8. An apparatus as claimed in claim 6 or 7 wherein said lifter plate and/or said periodic lifter plate are connected to a valve means displaceably located in a valve seat, wherein an open path is defined between said first or said second fluid retaining means and said second outlet port when said valve means is displaced from said valve seat.
9. 9. An apparatus as claimed in claim 8 wherein said valve means comprises a syphonic member capable of drawing fluid from said first or said second fluid retaining means.
10. 10. Use of a multi-purpose water filter in a water chamber for rodding and inspection.
11. 11. Use as claimed in claim 10 of a water filter as defined in any of claims 1 to 9 in a water chamber for rodding and inspection.