GB2451056A

GB2451056A - Filter

Info

Publication number: GB2451056A
Application number: GB0625683A
Authority: GB
Inventors: Dylan Bagust
Original assignee: Bishop & Bagust Ltd
Current assignee: Bishop & Bagust Ltd
Priority date: 2006-12-22
Filing date: 2006-12-22
Publication date: 2009-01-21
Anticipated expiration: 2026-12-22
Also published as: GB2451056B; GB0625683D0

Abstract

A filter assembly for use at an outlet from a vessel in which liquid material containing suspended matter is held. The assembly comprises a conduit (12, 28). The conduit (12, 28) has at a first end means (14) for releasably sealing said conduit to said outlet (60) in a liquid-tight manner. The conduit has at a second, free, end means (38) for releasably attaching a filter (48) in a liquid-tight manner. The free end of the conduit (12, 28) is movable between a first position in which said filter (48) is at least partially submerged for filtration in said liquid material and a second position in which said free end is withdrawn from said liquid material, above the surface thereof allowing said filter (48) to be released from said conduit without unfiltered fluid material passing through said conduit (12, 28) to said outlet (60).

Description

Filter The invention herein described relates to methods and apparatus for providing filtration means in flow channels for liquid having suspended solids therein.

The invention is particularly though not exclusively applicable to filtration of waste water. In the purification of water at a water treatment plant, settlement is carried out in settlement tanks, in which solids suspended in waste water are allowed to settle under gravity to the bottom of the tanks, and relatively clean water, substantiallyfree of solids is drained off the at the surface of the tanks, usually via a shallow perimetric channel known as a launder channel, and is then discharged into a local watercourse.

Over a period of time the launder channel becomes dirty and as a result periodic cleaning and maintenance must be carried out on it. Due to the fact that the maintenance work causes contaminants to be disturbed within the tank and to be carried over into the launder channel, then either the lank must be taken off line, or all water leaving the tank is diverted to be reprocessed in order to ensure said contazninani do not reach the watercourse. The practice of reprocessing the contarnitej outflow requires the shutdown of the tank to incoming water and for the water plus solids to be re-circulated by a pump. It is a complicated, time-consuming, wasteful and expensive procedure.

The problem of preventing contamination of watercourses during the cleaning process is also becoming more acute due to recent European legislation regarding clean water discharge standards.

The present invention seeks to ameliorate these disadvantages by the use of a replaceable inline filter assembly in the final tank outlet, allowing the settlement tank to be cleaned without the need for site shutdown and without the need to re-circulate the contaminated water whilst cleaning the tank.

According to one aspect of the invention there is provided a filter assembly for use at an outlet from a vessel in which liquid material containing suspended matter is held, comprising a conduit having at a first end means for releasably sealing said conduit to said outlet in a liquid-tight manner such that only liquid passing through said conduit may pass through said outlet, and at a second, free, end means for releasably attaching a filter element in a liquid-tight manner such that only liquid passing through said filter element may pass through said outlet, said conduit being disposed such that said free end is movable between a first position in which said filter element is at least partially submerged for filtration in said liquid material and a second position in which said free end is withdrawn from said liquid material, above the surface thereof allowing said filter element to be released from said conduit without unfiltered fluid material passing through said conduit to said outlet.

It is clear that the length of said conduit from said first end to said second, free, end must be sufficiently long to allow said free end to be drawn up above the surface of the liquid material, and that this length will depend upon and be tailored to suit the distance from the point of securement of the first end at the outlet, to the surface.

Therefore, although the outlet is generally near the surfce, if it is not the conduit will need to be correspondingly longer.

Preferably, the means for releasably sealing said conduit to said outlet in a liquid-tight maimer also holds the assembly in a static position within the outlet. This is so that the flow through the outlet does not cause the filter assembly to dislocate.

Desirably, a portion of the conduit adjacent to the first end is formed out of a rigid material. l'his to provide a surface of the conduit to utilise in sealing the conduit within the outlet.

Advantageously, a portion of the conduit adjacent to the second end is formed out of a non-rigid material. This is to facilitate the movement of the filter element from the first to the second positions.

Preferably, the means of releasably sealing said conduit to said outlet in a fluid-tight maimer is an inflatable sleeve for, when inflated, imparting a force to both a wail of the outlet and to said first (rigid) end of said conduit. This method enables the assembly to be installed by inserting the conduit in the outlet and inflating the sleeve until a sufficient seal is obtained, and removed by deflating the inflatable sleeve, enabling it to be relocated easily and quickly; and also to fit a variety of outlets of differently-sized cross-section.

Conveniently, the conduit is composed of impermeable material, in order to prevent contaminated fluid from passing through the outlet without flowing through the filter.

Alternatively, the conduit may be composed of filter material, in order to increase the volume of liquid that can be filtered per unit time, and also possibly to reduce the complexity of the arrangement.

Desirably, the conduit is composed of part filter material and part impermeable material.

Advantageously, the filter element is received within the conduit, as this configuration of the device is very space efficient.

Alternatively, the filter element is exterior to the conduit. This configuration may provide greater accessibility to the filter element and thereby aid filter element exchange.

Alternatively, in use, there is no interssuception of the conduit and the filter element is received within the conduit.

Otherwise, in use, there is no interssuception of the conduit and the filter element is exterior to the conduit.

According to another aspect of the invention there is provided a conduit assembly for use at a vessel outlet in which fluid material is held, comprising a rigid conduit, of a size such that it can be received within said outlet, having, on at least part of the outer surface between the conduit ends, a partially or fully surrounding inflatable sleeve for relcasably sealing said conduit within said outlet in a fluid-tight manner such that only liquid passing through said conduit may pass through said outlet.

Preferably, the inflatable sleeve also holds the assembly in a static position within the outlet. This is so that the flow through the outlet does not cause the filter assembly to dislocate.

Desirably, there are means of releasably attaching a filter element in a fluid-tight manner such that only liquid passing through said filter element or flow control device may pass through said outlet.

It will be appreciated that although both aspects of the invention herein described relate to the positioning or replacement of a filter within an outlet, another device, for example a flow control device, may be used in place of the filter without altering the essence of the invention.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of an embodiment of the apparatus; Figure 2 shows an enlargement of a portion of the apparatus at Figure 1; Figure 3 is a diagrammatic view of an embodiment of the invention showing the filter assembly in use; Figure 4 is end-on schematic view of the same embodiment as that in Figure 1; Figure 5 is a schematic view of the embodiment in Figure 1 in a filter exchange position; Figure 6 is a diagrammatic view of the filter assembly in the filter exchange position; Figures 7a.c are photographic representations of the filter exchange process.

Figure 8 is a cross section view of the filter element connection to a conduit.

The filter assembly shown generally as 10 is used in an outlet of a settlement tank having a launder channel 63 therein. In normal circumstances the settlement tank allows suspended solids to settle whereas largely uncontaminated liquid flows into the launder channel 63 and thence through an outlet 60 to a river or other watercourse.

However periodic cleaning of the tank and especially the launder channel 63 is required and to do this while the tank is on line results in disturbance of the settled solids and their exit from the tank via the launder channel 63 and outlet 60. When it is desired to clean the tank and launder channel the filter apparatus of the present invention is fitted whilst cleaning takes place.

The embodiment of Figure 1 comprises a filter assembly indicated generally as 10.

As seen best in figures 1-3 the conduit comprises a generally cylindrical rigid main body 12 and impermeable flexible interconnecting sleeve 28. An inflatable sleeve 14 surrounds the main body 12. The inflatable sleeve consists of an inflatable bladder (not shown) and a flexible protective outer cover 16. Both the bladder and cover are secured to the main body using circular clips 18,20. The inflatable bladder is airtight and has an opening that receives a length of tubing 22 in an airtight manner, through which air is passed to fill the bladder, and hence inflate the sleeve, through an inlet 24. A hand pwnp 26 is connected to the inlet 24 to inflate the bladder. A first end of the impermeable interconnecting sleeve 28 is fastened to one end of the main body 12, by means of a first double gasket 30 as is seen best in Figure 4. The first double gasket consists of a flange 32 on the end of the main body 12 and an annulus 34 of corresponding size, between which the first end of the interconnecting sleeve 28 is inserted, fastened together with bolts 36. The bolts 36 are tightened so as to form a watertight seal between the main body 12 and the interconnecting sleeve 28. As seen best in Figure 8, the second, free end of the interconnecting sleeve 28 is received within a second double gasket 38, composed of two annuli 42,44 of a sufficiently small diameter so that they can pass through the annular opening in the first double gasket 30. The interconnecting sleeve 28 is secured between the annuli 42,44, which are fastened together with bolts 40 to provide a watertight seal. One annulus 44 is provided with a projection, which protrudes from an inner radial edge of the annulus in a direction perpendicular to its radius; and at its end there is a ledge 46 (fig 8), which forms an annular lip surface perpendicular to the projection extending radially inwardly. A filter 48 of semi-permeable membrane material, generally cylindiical in shape, comprising a first closed end 50, sealed in a manner such that no contaminant can pass from inside the cylinder to the outside or vice-versa; and a second end attached at its circumference to a filter attachment annulus 52. The filter attachment annulus 52 has an Outer radius, which is less than that of the internal radius of the second double gasket 38, but greater than the smallest radius of the annular lip 46.

This enables the filter attachment annulus to be received within the annulus 44. A creumferentially.tjed retaining annulus 54 is received in a corresponding thread 56 in annulus 44 and is used in combination with an intermediate o-ring 58 to seal the filter attachment annulus 52, and hence the filter 48, against the annual ledge 46 of the annulus 44, and hence with the interconnecting sleeve 28, in a fluid-tight manner.

The various principal components are shown in working configuration in Figure 3. A chain 66 is attached at one end to the second double gasket 38 and has a free end held so that it can be grasped by operative near the outlet 60.

In use, the assembly 10 is inserted, with the sleeve 14 deflated, into a desired position within a cylindrical outlet 60 from a vessel 62 containing contaminated liquid to be filtered 62. The assembly 10 is orientated within the outlet 60 such that the end of the main body 12 comprising the first double gasket 30 is located closest to the vessel 62.

The inflatable sleeve 14 is inflated air through the tube 22 from the pump 26, to an extent such that the main body l2is sealed within the outlet 60 in a fluid-tight manner such that only liquid passing through the main body 12 may pass through said outlet 60. The inflated sleeve l4 also impartsa force on the main body 12 and aforce on the outlet 60 such that it is held in a static position within the outlet 60. In the embodiment described, as is best seen in Figure 3, there is an interssuception of the main body by the conduit and accordingly the flow through the outlet causes the interconnecting sleeve 28 and second double gasket 38 to be received within the main body 12. This is the in-flow' configuration of the device. Contaminated liquid contained in the vessel 62 passes through the main body 12, interconnecting sleeve 28 and filter 48. The filtrate then emerges into a contaminate-free portion of the outlet 64. It will be appreciated that although the filter 48 is shown in this embodiment protruding from the main body 12 and the interconnecting sleeve 28 is shown contained entirely within the main body 12; the filter 48 may be contained entirely within the main body 12, or the interconnecting sleeve may extend beyond the main body 12 as and when appropriate, depending upon the lengths of the various components chosen for the particular application and the length of the outlet 60.

Whilst the filter assembly 10 is in situ it may become necessary to exchange the filter element 48 as a result of, but not limited to, the filter element becoming degraded by use, or the required operating characteristics of the filter element changing. Filter exchange achieved by first pulling a chain 66, towards the vessel 62, causing the interconnecling sleeve 28, double gasket 38 and filter element 4810 move through the main body 12 towards the vessel 62 and be elevated to a position where the second double gasket 38 is above the level of contaminatej fluid in the vessel 62, as is best seen in Figure 6. In this elevated, or filter exchange, position, the contaminant is prevented from entering the assembly conduit 12, 28 by the non-permeable nature of the interconnecting sleeve 28. It will be noted that the length of the interconnecting sleeve 28 is chosen to be of a length so as to be able to accommodate the location of the assembly 10 and yet still allow the first double gasket 30 to be drained above the contaminant vessel 62 fluid level 61. The filter changeover process is best seen in Figuress 7a-c. The threaded retaining annulus 54 is rotated in an anti-clockwise manner to release it from engagement with corresponding thread 56 in annulus 44 of the second double gasket 38. The retaining annulus 54 and o-ring 58 are separated from the second double gasket 38. The filter element 48 is then withdrawn from the second double gasket by the filter attachment annulus 52 ensuring that contaminant material inside the filter element does not fall into the interconnecting sleeve and hence through the outlet. The refitting process is a reversal of the removal process.

Once refitting has be carned out the interconnecting sleeve 28 and filter element 48 are returned to the in-flow configuration by releasing the chain 66, the force of the liquid on the interconnecting sleeve 28 generally causing relocation within the main body 12, with manual help if necessary.

In order to remove the filter assembly 10 from the outlet 60 air is released from the inflatable sleeve 14 through the connected tube 22 and outlet 24, hence causing the bladder and hence the sleeve to deflate. The assembly is then withdrawn from the outlet 60 by pulling the assembly out of the outlet 68 using the removal chain 68, in a direction generally opposite to the direction of fluid flow within the outlet 60. The assembly removal chain 68 is attached at one end to a securing eyelet 70, which is mechanically connected to the first double gasket 30. The other end of the chain is located exterior to the outlet 60 and vessel 62 in a direction opposite to that of outlet flow.

A plurality of differently sized main body 12 and sleeve 14 components may be supplied so that a choice can be made as to which combination of the two is appropriate for different dimensions of outlet 60.

It will be appreciated that the sealing of the sealing of the conduit in liquid-tight manner, is not always required. In the embodiment described, the seal may not need to be absolutely liquid-tight, so long as the suspended matter is not able pass through the seal.

It will be appreciated that a number of modifications can be made to the device within the scope of the invention.

Claims

Claims 1. A filter assembly for use at an outlet from a vessel in which liquid material containing suspended matter is held, comprising a conduit having at a first end means for releasably sealing said conduit to said outlet in a liquid-tight manner such that only liquid passing through said conduit may pass through said outlet, and at a second, free, end means for releasably attaching a filter element in a liquid-tight manner such that only liquid passing through said filter element may pass through said outlet, said conduit being disposed such that said free end is movable between a first position in which said filter element is at least partially submerged for filtration in said liquid material and a second position in which said free end is withdrawn from said liquid material, above the surface thereof allowing said filter element to be released from said conduit without unfiltered fluid material passing through said conduit to said outlet.
2. The filter assembly of claim 1 where the means for releasably sealing said conduit to said outlet in a liquid-tight manner also holds the assembly in a static position within the outlet.
3. The filter assembly of claims 1 and 2 where a portion of the conduit adjacent to the first end is formed out of a rigid material.
4. The filter assembly of claims 1-3 where a portion of the conduit adjacent to the second end is formed out of a non-rigid material.
5. The filter assembly of claims 1-4 where the means of releasably sealing said conduit to said outlet in a fluid-tight maimer is an inflatable sleeve which, when inflated, imparts a sealing force on both a wall of the outlet and the first end of said conduit.
6. The filter assembly of claims 1-5 where the conduit is composed of impermeable material.
7. The filter assembly of claims 1-5 where the conduit is composed filter material.
8. The filter assembly of claims 1-5 where the conduit is composed of part filter material and part impermeable material.
9. The filter assembly of claims 1-8 where, in use there is an interssuception of the conduit and the filter element is received within the conduit.
10. The filter assembly of claims 1-8 where, in use there is an interssuception of the conduit and the filter element is exterior to the conduit.
11. The filter assembly of claims 1-8 where, in use there is no interssuception of the conduit and the filter element is received within the conduit.
12. The filter assembly of claims 1-8 where, in use there is no interssuception of the conduit and the filter element is exterior to the conduit.
13. An assembly as in claims 1-12 where the fluid material may or may not contain a contaminant and the filter element is replaced by a flow control device.
14. A conduit assembly for use at a vessel outlet in which fluid material is held, comprising a rigid conduit, of a size such that it can be received within said outlet, having, on at least part of the outer surface between the conduit ends, a partially or fully surrounding inflatable sleeve for releasably sealing said conduit within said outlet in a fluid-tight manner such that only liquid passing through said conduit may pass through said outlet.
15. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims. S. * S.. *54* * . * *5 SS *

S 5. * S. * . * *.S. S. * * .* * *4

15. The conduit assembly of claim 14 where the inflatable sleeve also holds the assembly in a static position within the outlet.

16. The conduit assembly of claims 14 and 15 where there are means of releasably attaching a filter element or flow control device in a fluid-tight manner such that only liquid passing through said filter element or flow control device may pass through said outlet.

17. An arrangement substantially as described above, with reference to the accompanying drawings.

18. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.

* AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS:-Claims 1. A filter assembly for use at an outlet from a vessel in which liquid material containing suspended matter is held, comprising a conduit having at a first end means for releasably sealing said conduit to said outlet in a liquid-tight manner such that only liquid passing through said conduit may pass through said outlet, and at a second, free, end means for releasably attaching a filter element in a liquid-tight manner such that only liquid passing through said filter element may pass through said outlet, said conduit being disposed such that said free end is movable between a first position in which said filter element is received within said outlet and is at least partially submerged for filtration in said liquid material and a second position in which said free end is withdrawn from said liquid material, above the surface thereof, and hence is also withdrawn from said outlet, allowing said filter element to be released from said conduit without unfiltered fluid material passing through said conduit to said outlet.

2. The filter assembly of claim 1 where the means for releasably sealing said ::: conduit to said outlet in a liquid-tight manner also holds the assembly in a static position within the outlet.

I : 20

: * : 3. The filter assembly of claims 1 and 2 where a portion of the conduit adjacent to the first end is formed out of a rigid material. l'o

4. The filter assembly of claims 1-3 where a portion of the conduit adjacent to the second end is formed out of a non-rigid material.

5. The filter assembly of claims 1-4 where the means of releasably sealing said conduit to said outlet in a fluid-tight manner is an inflatable sleeve which, when inflated, imparts a sealing force on both a wall of the outlet and the first end of said conduit.

6. The filter assembly of claims 1-5 where the conduit is composed of impermeable material.

7. The filter assembly of claims 1-5 where the conduit is composed filter material.

8. The filter assembly of claims 1-5 where the conduit is composed of part filter material and part impermeable material. S. *

III

*::* 9. The filter assembly of claims 1-8 where, in use there is an interssuception of : *** the conduit and the filter element is received within the conduit. I.e. * 20

: .. 10. The filter assembly of claims 1-8 where, in use there is an interssuception of II * the conduit and the filter element is exterior to the conduit.

11. The filter assembly of claims 1-8 where, in use there is no interssuception of the conduit and the filter element is received within the conduit.

12. The filter assembly of claims 1-8 where, in use there is no interssuception of S the conduit and the filter element is exterior to the conduit.

13. An assembly as in claims 1-12 where the fluid material may or may not contain a contaminant and the filter element is replaced by a flow control device.

14. An arrangement substantially as described above, with reference to the accompanying drawings.