WO2005115582A1

WO2005115582A1 - Filtration device

Info

Publication number: WO2005115582A1
Application number: PCT/GB2005/002033
Authority: WO
Inventors: Simon Douglas Reynolds; Andrew Woodham
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-05-25
Filing date: 2005-05-24
Publication date: 2005-12-08
Anticipated expiration: 2006-11-25
Also published as: GB0411608D0

Abstract

A portable device for filtering water comprising an inlet, a filtration zone and an outlet, whereby water to be filtered enters the filtration zone through the inlet, passes through the filtration zone and passes out through the outlet, the filtration zone comprising a plurality of filters of decreasing mesh size. Preferably, the filter and/or baffle plates are removable from the device. More preferably, the filters are made from cross-weave/woven stainless steel mesh and the device is suitable for filtration of muddy water.

Description

FTT.TRATION DEVICE

The present invention relates to a portable filtration device and, in particular, a. filtration device for removing solid matter from water. There are many circumstances when a leakage of water or flooding occurs which results in ^'a large volume of water containing solid, semi-solid or particulate material. This can often occur when work is being carried out involving underground cables or pipes or to repair broken water pipes. When such flooding occurs, a large volume of water which contains such solid material may need to be removed from the location before further or remedial work can be carried out. Often, the dirty water may simply be pumped to another location, such as a holding tank,, or pumped into the mains drainage system. The latter option has the disadvantage of introducing a large amount of solid and semi-solid material into the mains drainage system which can block pipes and cause further damage and flooding, and is therefore forbidden in some countries. Although devices for cleaning water contaminated by solid and semi-solid particulate material are known, these are generally fixed systems which are constructed at ^' a particular site to deal with a specific long term problem; as disclosed in US4689145A, JP2000070617A and FR2833855A. The devices disclosed in these documents cannot be transported or installed quickly in order to deal with unexpected or temporary leakage of water or flooding. The present invention seeks to provide a filtration device to alleviate these problems. According to the present invention there is provided a portable device for filtering water comprising an inlet, a filtration zone and an outlet, whereby water to be filtered enters the filtration zone through the inlet, passes through the filtration zone and passes out through the outlet, the filtration zone comprising a plurality of filters of decreasing mesh size. By portable, it is meant that devices of the present invention may be transported from site to site, and preferably without the need to use specialist lifting equipment. In addition, devices of the present invention may be further adapted to make them easier to move into position, for example, by being fitted with handles to assist in their lifting and/or being fitted with wheels, which may be attached either to the base of the device or to a cradle adapted to receive the device of the invention. Preferably, devices of the present invention are generally rectangular, having a length in the direction of the flow of water preferably of from 1 to 5m, more preferably 1 to 2m, for example 1.2m. Devices of the present invention also have a preferred width of from 400mm to lm, more preferably 500mm to 700mm, for example 640mm, and a preferred depth of from 400mm to lm, more preferably 500mm to 750mm, for example 640mm. Devices of the present invention will preferably have an overall volume of from 100 to 5000 litres, more preferably from 200 to 2000 litres, and most preferably from 300 to 750 litres . Devices of the present invention may be made of any material having sufficient rigidity to withstand the weight of water that will be contained when the device is operating at full capacity, for example, stainless steel, aluminium or suitably reinforced fibrous materials. Preferably, one or more of the filter plates is removable. Conveniently, the device further comprises one or more baffle plates. Advantageously, one or more of the baffle plates is^' removable . Preferably, the device comprises at least two filters, more preferably at least 3 filters. Conveniently, at least one of the filters is removable, and more preferably all of the filters are removable. This permits blocked filters to be cleaned and damaged filters to be easily replaced. * As will be appreciated, the pore size of the filters used in devices of the present invention may be selected to take into account the type and variety of materials contaminating the water to be filtered. For example, when the contaminating material is relatively large at least one filter having a large pore size will be preferred, whereas when the contaminating material is generally small and semi-solid, or particulate, at least one filter having a small pore size will be preferred. Various combinations of filter sizes may also be used when there is a mixture of contaminants of various sizes present. When the device of the present invention comprises three or more filters, it is preferred that the first filter will have apertures of from 3 to 7.5mm in diameter, preferably 5.5mm, the second filter will have a mesh size of from 100 to 500 microns, and the third filter will have a mesh size of from 10 to 150 microns. Advantageously, the filters comprise cross-weave/woven stainless steel mesh. Conveniently, the device is for filtration of muddy water. The inlet of the devices of the present invention may comprise a single entry port, to which may be connected a pipe leading from a pump draining the water that is to be filtered or, alternatively, may comprise two or more such entry ports. In addition, the outlet of devices of the present invention may comprise a single conduit through which water may be passed out of the device, or may comprise two or more such conduits, preferably three. Devices of the present invention preferably comprise acces.s points in the top of the device, and more preferably are fitted with a lid to provide access to the interior of the entire device, so that, for example, the filters and any baffle plates that may be present may be inspected, cleaned and/or replaced. Such a lid may be fully removable, or may be hinged. It is preferred that, if the device of the present invention comprises one or more access hatches or a lid, means are also provided to ensure that the access hatches or lid, can be secured in the closed position, for example, catches or locking mechanisms. It is preferred that devices of the present invention are fitted with an overflow port, preferably at the end of the device into which water first flows, to ensure that water that has not passed through the device is returned in the direction from which the contaminated water reaches the device, rather than in the direction in which treated water is passed. The present invention also provides a method of removing solid, semi-solid or particulate materials from water containing such materials, comprising pumping the water to be treated to the inlet of a device of the present invention, passing the water through the filtration zone and out of the outlet thereof. Water filtered through devices of the present invention by the method of the present invention may be further treated after passing out of the outlet of the device of the present invention, for example, by passing through further filters (eg, sponge or depth filters) , and/or by being pumped into a dry-well which might be dug at a particular site if a particularly heavy leakage or flooding had occurred. In the method of the invention, water may be pumped through the device of the invention at a flow rate of up to 2000 litres per minute, preferably from 500 to 1200 litres per minute, for example 800 litres per minute. The present invention will now be described, by way of example, with reference to the accompanying drawings in which Figure 1 is a top view of a device according to the present invention with the lid removed;

Figure 2 is a cross-sectional view of the device along A-A of Figure 1;

Figure 3 is an end view of the device; Figure 4 is a further end view of the device; Figure 5 is an end view of the lid; Figure 6 is a plan view of a baffle-plate; Figure 7 is a plan view of a perforated baffle-plate; Figure 8 is a plan view of a first filter-plate; Figure 9 is a plan view of a second filter plate, and;

Figure 10 is a schematic cross-section of the device showing flow of water. Turning to figure 1, a device 2 of the present invention is shown without a lid for clarity. The device 2 is a filtration unit of substantially cuboid shape through which dirty water to be cleaned is passed. The device 2 defines a chamber 4 through which the water is passed. The chamber 4 is defined by a first end wall 6, a second end wall 8, a first side wall 10 and a second side wall 12, in addition to the floor of the device 2. The walls of the device 2 are made of stainless steel. The length of the side walls 10 and 12 is 1.2m. The length of the end wall 6 and 8 is 640mm, and the height of each of the side walls 10 and 12, and the end walls 6 and 8 is 640mm. In the first end wall .6, there is located an inlet 14 of 63mm diameter and an overflow outlet 16 of 63mm diameter. In the second end wall 8, there is located a first outlet 18 and a second outlet 20. The diameter of each of the outlets 18 and 20 is 63mm. There are a number of baffles and filters which are located in the chamber 4 and which are slidably removable as will be discussed in further detail below. Working from the first end wall 6 towards the second end wall 8, there is a first baffle plate 22, a second baffle plate 24 and a third baffle plate 26. Beyond the baffle plates, there is a first filter plate 28, a second filter plate 30 and a third filter plate 32. There are four handles 34 provided on the exterior of the device 2, one towards each end of the side walls 10^" and 12. The handles 34 allow the device 2 to be moved around to a desired location and also enable the device to be secured to vehicles etc for transportation. There is a cross-bar 36 placed between the first side wall 10, the second side wall 12 in order to give the unit rigidity. Figure 2 is a cross-sectional view along A-A of figure 1. Beneath the floor 38 of the chamber 4 there is located a number of support legs 40. All of the baffle plates 22, 24 and 26 and filter plates 28, 30 and 32 are slidably mounted within the chamber 4 and may be removed for cleaning and repair by pulling them upwards out of the chamber 4. All of the baffle and filter plates span the width of the chamber 4 from the first side wall 10 to the second side wall 12. The first and third baffle plates 22 and 26 reach from the top of the chamber 4 towards the bottom of the chamber but leave a gap between their lower end and the floor 38 of the chamber 4. The second baffle plate 24 reaches from the floor 38 upwards towards the top of the chamber 4 but leaves a gap between the upper end of the plate 24 and the top of the chamber 4. Also, the second baffle plate 24 has a number of small perforations to allow some flow of water 'through the plate. The baffle plates thus direct the flow of incoming water down below the first baffle plate 22, up and over the top of the second baffle plate 24 and then down and below the third baffle plate 26. This allows the incoming water to be slowed down and allows some settling of solid material. After passing around the baffle plates, the water may then pass through the first filter plate 28, which is perforated with a large number of apertures of 5.5 millimetre diameter. The water then passes through the second filter plate 30 which consists of two grids which sandwich a 300 micron filter mesh. The water may then pass through the third filter plate 32 which is similar in construction to the second filter plate 30 except that it comprises a 100 micron mesh. The water may then pass out of the device through the outlets 18 and 20. The increasingly small pore size of the filter plates allow 5 for increasingly small particles of- matter to be removed from the water. The filtered water is then clean enough to be pumped directly into the main water drains for disposal. In 'practice, a flooded trench may be emptied by introducing a hose attached to a trench pump. The dirty water

10 is then passed through the pump and into the chamber 4 via the inlet 14. The incoming water is then slowed down by passage around and through the baffle plates 22, 24 and 26 before being filtered through the filter plates 28, 30 and 32. The filtered water is then passed through outlets 18 and 20 for

15 disposal. The pumping may be periodically stopped in order to remove accumulated solid and semi-solid material from the chamber 4 and for removal and cleaning of the baffle and filter plates. Figure 3 shows an end view of the device 2 with the inlet

20 14 and the overflow outlet 16 on the first end wall 6. The support legs 40 can be seen to have an I-beam construction. These legs may alternatively be replaced by wheels fitted at each corner of the device. Figure 4 shows the opposite end view of the device 2 with the outlets 18 and 20 being

25 positioned towards the bottom of the device in the second end wall 8. Figure 5 shows the corresponding end view of the lid 42 which is removably attachable to the top of the device 2. The lid is provided with 4 catches to ensure that it is fixed in place during use and transport of the device.

30 Figure 6 shows the first baffle plate 22 which comprises a sheet of stainless steel. The third baffle plate 26 is substantially identical to the first baffle plate 22. Figure 7 shows the second baffle plate 24. It is of similar construction to the first and third baffle plates 22

35 and 26 except that it has an array of apertures of 11 millimetre diameter in its lower half. Alternatively, the second baffle place 24 may comprise a single row of 7 apertures of 8mm diameter placed 45mm above the bottom of the baffle plate 2.4. As mentioned above, these allow for the passage of water through the baffle plate. Figure 8 shows the first filter plate 28 which comprises a sheet of stainless steel with a very large number of apertures' therethrough. The apertures are of 5.5. millimetre diameter. Figure 9 shows the second filter plate 30 which comprises two wire grids 48 which sandwich a fine mesh material 50. The mesh material 50 comprises cross-weave/woven stainless steel mesh which has a 300 micron mesh. The third filter plate 32 has a substantially identical structure to the second filter plate 30 except it has a 100 micron mesh. Figure 10 shows a cross-section of^" the device 2 in use. The chamber 4 of the device 2 is filled with water up to the level 52. As can be seen, water enters via inlet 14 and is directed downwards under the first baffle 22. Thereafter, the water is directed upwards and over the second baffle 24. There is a small gap between the level of the water 52 and the top of the second baffle plate 24. The water then passes down and under the third baffle plate 26 before passing sequentially through the first, second and third filter plates 28, 30 and 32. The filtered water then leaves the device via the outlets 18 and 20. It is to be appreciated that the number of type of baffles and/or filter plates could be varied without departing from the scope or spirit of the present invention. , ^' .G:\300-304\W6D\303470\WO\SPEC01.WPD\SEE\jam

Claims

CLAIMS :

1. A portable device for filtering water comprising an inlet, a filtration zone and an outlet, whereby water to be filtered enters the filtration zone through the inlet, passes through the filtration zone and passes out through the outlet, the filtration zone comprising a plurality of filters of decreasing mesh size.

2. A device according to claim 1 wherein one or more of the filter plates is removable.

3. A device according to claim 1 or claim 2 further comprising one or more baffle plates.

4. A device according to claim 3 wherein one or more of the baffle plates is removable.

5. A device according to any of the preceding claims comprising three filters.

6. A device according to claim 5 wherein the apertures in the first filter are from 3 to 7.5mm in diameter, the mesh size of the second filter is from 100 to 500 microns and the mesh size of the third filter is from 10 to 150 microns.

7. A device according to any preceding claim wherein the filters comprise cross-weave/woven stainless steel mesh.

8. A device according to any previous claim for filtration of muddy water.

9. A device according to any preceding claim including lifting handles.

10. A device according to any preceding claim having a volume of from 150 to 5000 litres.

11. A method of removing solid, semi-solid or particulate materials from water containing such materials, comprising pumping the water to be treated to the inlet of a device as claimed in any preceding claim, passing the water through the filtration zone and out of the inlet thereof.

12. A method according to claim 11 wherein the water to be treated is passed through the device at a rate of from 500 to 1200 litres per minute.

13. A device ' substantively as hereinbefore described with reference to and as shown in the accompanying drawings.

14. A method substantially as hereinbefore described.