Filter for drainage gully

Abstract

A filter bag 2 for a drainage gully e.g. a floor or road drain (1, Fig 2). For installation within an upper region of a gully pot (34) via an interference fit provided by a compressible and / or expand

Description

Field of the Invention. The present invention relates generally to a filter for a drainage gully. Background A gully is a drainage fitting with an open top, base and an outlet to one or more sides for connecting wastewater outlets or stormwater / rainwater outlets to suitable drains. Different types of gullies exist but generally include a grate or grid at ground / road level over the opening, a hopper or chute that directs flow into the gully pot or basin and then an outlet pipe connected to a main drain. A bottle trap gully includes a removable central chamber. A gap between the chamber and the wall of the gully forces water that has flowed into the gully to be forced upwardly to a side pipe forming the outlet. The configuration of gullies is such that when the flow of water stops, a small amount of water remains at the base of the pot and prevents unpleasant odours and gases from escaping back into the air. Gullies can often receive debris which may lead to blocking of drainage pipes. Construction sites, transportation networks and other urbanisation projects may also lead to contaminated water flowing into the gullies which, during times of heavy rainfall, may result in overflow, causing contamination of the surrounding area and water course. This can be particularly problematic in areas of building work where drainage systems are the first utility to be installed at a new site. Building work is then carried out which creates significant debris, such as mud, concrete and hydrocarbons from diesel engines, which is washed into the gully. It is clearly undesirable for this to end up in the water system and the debris may collect at the base of the pot, blocking the flow of water. It is also environmentally unfriendly for pollutants, such as oils to be washed into the water course. It is known to provide a removable filter that may be placed within the gully to collect debris, hydrocarbons and other contaminants to prevent their entry into the water system but it has proven very difficult to retain these filters in the correct location within the pot. For example, one type of filter, known as EnviroHorn™ of Green Rhino, United Kingdom, is hung from the top of the gully, being retained by capturing the top part of the filter between the gully grate and the ground. Another example is Gully Guard™ (GB2472690B) of Forest Drainage Products Limited, United Kingdom which provides a filter bag of a netting material filled with polystyrene balls or beads which enable the bag to float and be retained in the pot. While the prior art filters are entirely fit for purpose, there are some drawbacks, such as it being difficult and timeconsuming to place the filter within the gully and have it retained securely in place. It is an object of the present invention to provide an improved filter bag for a gully that aims to overcome, or at least alleviate, the abovementioned problems. Summary of the Invention. According to a first aspect of the present invention there is provided a gully filter comprising a bag formed of a porous material or mesh, the bag having at least one at least partially expandable support flange around a perimeter of the bag, wherein, in use, the flange is configured to press against an inner wall of a gully pot to retain the bag in position. Preferably the filter comprises a cylindrical bag formed of a net material. More preferably, the net comprises knitted high-density polyethylene (HDPE) filament. The at least one at least partially expandable support flange may be any size and shape dependent upon the size of the bag and the gully pot into which it is to be installed. For example, the flange may be annular such as in the form of a circular ring, rectangular or triangular. The flange is configured to expand and press against the inner wall of the gully pot once positioned therein. In one embodiment, the expandable support flange may be in the form of a bracket provided with a ratchet mechanism wherein the ratchet may extend the perimeter of the bracket once in situ within the gully pot to retain the bracket against the inner wall of the gully pot. It is to be appreciated that the bag may be provided with multiple, spaced apart expandable support flanges to retain the bag in position in the gully pot, for example one being towards the top of the bag and one towards the bottom of the bag. Alternatively, a single flange may be provided. More preferably, the flange is comprised of an at least partially compressible material wherein the flange expands against the inner wall of the gully pot once in situ. Preferably, the bag is provided with at least one ring of an at least partially compressible material for providing the expandable support flange. More preferably, the ring is provided towards the mouth of the bag. Alternatively, a pair of rings being spaced apart to provide an upper support ring near to the top of the bag and a lower support ring near to the base of the bag. At least one of the rings is preferably formed of a foam material, having a small degree of compressibility. In a preferred embodiment, each ring is a foam ring, more preferably being formed from a closed cell cross linked polyethylene produced by extrusion. The dimension of the at least one ring will depend upon the size of the gully into which the filter is to be fitted. Preferably, the outer diameter of the ring is 440500mm, preferably 450-490mm, especially about 480mm. The expandable support flanges or rings may be attached to the bag by any suitable means, for example being sewn into the material of the bag, adhered thereto and / or provided with fastenable straps for securing to the bag and around the ring, for example using Velcro™. It is preferable for at least the outer sides of the expandable support flange, such as the ring, to be reinforced with a stronger material than that of the ring and the net / mesh of the bag. For example, the outer sides may be provided with a non-porous material, such as a polyurethane (PU) + fluorocarbon (FC) treated polyester fabric. Preferably, the material comprises rubber. This serves to protect both the more fragile netting around in the ring and the ring itself. Alternatively, the at least one expandable support flange may comprise a sprung ring, for example of sprung steel. The at least one expandable support flange, such as a ring may be formed of a plastics or rubber material, for example being formed as tubing and then joined at the ends to form a ring. The ring may be formed from a hollow plastics material or may be a hollow or solid rubber material. In yet another embodiment, the at least one support expandable support flange may be inflatable, for example being an inflatable ring, wherein the ring is inflated to press against the wall of the gully pot. Preferably, if multiple rings are provided, the rings are of an identical type. However, it is to be appreciated that different types of rings may be provided, such as a rubber ring and a foam ring, or a foam ring and an inflatable ring. Optionally, the filter bag may be provided with an absorbent material for removing oils, hydrocarbons and other contaminants, such as a polypropylene (PP) meltblown fabric and / or polypropylene (PP) / Acrylic electret needle punch. Preferably, the bag is provided with a pocket for receiving the absorbent material. The pocket may be attached to any inner surface of the bag but preferably is provided at the base of the bag. Preferably, the absorbent material is provided within a removable pouch for placement in the pocket. For example, the pouch may be made from the same material as the bag, such as a net material, or another type of mesh. The pouch may be provided with strips of the absorbent material. The pocket is preferably provided with a small opening to allow removal of the pouch. The bag may also be provided with a handle or straps to aid its removal from a gully. The handle may be a permanent or temporary attachment to the bag. A second aspect of the present invention provides a method of installing a filter bag into a gully, the method comprising: providing a filter according to a first aspect of the invention; inserting the filter into a gully; and securing the at least one expandable support flange within the gully by expanding, pressing or inflating the at least one flange against inner sides of the gully to engage the side of the flange with the sides of the gully to retain the bag in position. Preferably, the method includes engaging an upper and a lower flange to upper and lower regions of the sides of the gully. Brief Description of the Drawings. For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made by way of example only to the accompanying drawings in which: Figure 1A is an isometric view of a filter for a gully according to one embodiment of the present invention; Figure IB illustrates the side sectional view of the filter shown in Figure 1 A; Figure 2 is a section view of a gully fitted with the filter of Figures 1A and IB; Figure 3 A is an isometric view of a filter for a gully according to another embodiment of the present invention; and Figure 3B illustrates a side sectional view of the filter shown in Figure 3 A. Detailed Description The present invention provides an improved filter 2 for a drainage gully 1 that may be easily positioned and retained within the pot of a gully. It also allows for quick and easy removal of the bag from the pot for emptying of the filter or its replacement with a fresh filter. Figures 1A and IB illustrate a filter according to a preferred embodiment of the present invention. The filter comprises a cylindrical bag formed of a net material 4 made from knitted HDPE filament, although other mesh or porous materials may be used for the bag. Additionally, the bag is provided with two spaced apart foam rings 6, 8 formed from a closed cell cross linked polyethylene produced by extrusion. These rings provide some limited compressibility to these regions of the bag 2. The rings may have an outer diameter of, for example, 480mm, but their dimensions will depend upon the size of the gully into which the filter is to be fitted (a standard gully is 450mm diameter by 750mm deep). The top ring 6 is sewn into the top of the bag, being sandwiched between the net material 4 and a more durable non-porous material, such as a PU + FC treated polyester fabric 10. The bottom ring 8 is held in place inside the bag by four Velcro™ straps 12. The outer surface of the net that surrounds both rings is provided with the stronger polyester fabric 10 to provide regions that are more hardwearing than the net material of the bag, making the bag more durable in these areas. Additionally, a pocket 14 is provided at the base of the bag 2 containing a removable pouch 20. The pouch may be made from the same material as the bag, such as a net material, or another type of mesh. The pouch is provided with strips of material for absorbing chemical contaminants, such as hydrocarbons and oils. Preferably, the strips 22 are made from a PP meltblown fabric and / or PP / Acrylic electret needle punch. However, the pouch may contain any other type of absorption media for removing oil and hydrocarbons, including beads or foam that remove such contaminants. The bottom of the bag is provided with a small opening 18 to allow removal of the pouch 20 and the insertion of a fresh one. The top of the bag 2 is also provided with handles 18 to allow the bag to be lifted out of the gully more easily for emptying or replacement. However, it is to be appreciated that alternative means may be provided for its removal, such as a pair of eyelets being provided in the top rim which may receive pieces of rope with knots on the ends that can be passed through the eyelet one each side to assist with the removal of the filter bag from the drain. Figure 2 of the accompanying drawings illustrates the filter 2 of Figures 1A and IB fitted within one example of a type of drainage gully 1. The drainage gully 1 is installed beneath an opening at ground level and is connected to a mains drainage system via an outlet pipe 32. A pre cast concrete surround 30 receives a ribbed HDPE liner 34 which may also be made from pre cast concrete or clay to form the central chamber or gully pot. A precast concrete U shaped cover slab 36 is provided around the top of the gully for receiving a gully grating 38 at road level. Alternatively, suitable brickwork may be provided around the opening for receipt of the grating 38. An upwardly extending side pipe 37 is connected to outlet pipe 32 and a stopper 35 is provided for a rodding point. The whole gully is surrounded by appropriate concrete, mortar and / or bedding materials to provide a minimum coverage required to comply with engineering regulations. Once in position, water 40 will settle in the lower region of the pot 34. To install a filter bag according to the present invention, the gully grating is removed and a filter bag 2 is placed within the upper region of the pot 34. The bag is very flexible apart from the upper and lower foam rings that are slightly larger in diameter than the pot but have a small degree of compressibility brought about by the material of the rings. This allows both rings to be push fitted into the gully when installing the bag so that the bag becomes suspended in the gully, being retained in position by the outer sides of the rings pushing again the inner walls of the pot. In this manner, water 40 flows through the gully and any debris is caught by the netting material 4 of the bag to prevent it passing into the outlet pipe. Additionally, the absorbent material within the pouch 20 of the bag removes hydrocarbons, oils and other contaminants from the water 40. The positioning of the pouch 20 in a pocket 14 provided at the base of the bag 2 results in the pouch generally being located in the region of the upper surface of stagnant water within the pot which is where the contaminants would accumulate. The spaced apart foam rings allow easy positioning of the bag within the pot, retaining the bag both in its correct location and also retaining the bag in a fully open configuration within the gully. The outer sides of the rings 6, 8 are provided with a reinforcing material, such as PU + FC treated polyester fabric 10, as otherwise the friction between the bag and the inner walls would damage both the net 4 and the foam rings 6, 8. The bag can remain in situ until cleaning, maintenance or repair of the bag is required. At such time, the handle 18 may be used to pull the bag from the gully pot 34. Again, the compressible nature of the foam rings enables the rings to be released from engagement with the inner walls of the gully upon application of force, allowing the bag to be removed. The bag may then be cleaned and the pouch 20 replaced by removing the pouch through the opening 18 in the pocket 14. In the preferred embodiment of the invention a pair of foam rings are provided but it is to be appreciated that the bag may be provided with a single foam ring or any number of foam rings. Furthermore, while foam rings are preferred, the netting may be provided with regions of another type of material that enable it to expand against the inner walls of the gully. For example, any type of expandable support flange may be provided around at least an upper or a lower perimeter of the bag. Retaining spring rings may be provided. Alternatively, an expandable bracket may be provided, for example being expandable by means of a ratchet mechanism. However, the foam rings are ideal because they can be easily provided in a desired depth and diameter for placement and retention within the gully. They also aid handling of the bag. Other types of support rings include rings of a rubber material, a hollow plastics material and an inflatable material. It is to be appreciated that a circular or annular flange for compression against the inner wall of a gully pot is the most convenient configuration for the flange or ring but the invention is not limited thereto. For example, a square, rectangular or triangular flange may be provided around the perimeter of the bag. Furthermore, the bag may include other variations, such as the type of removal device and the positioning of the pouch. For example, the pocket may be mounted to an inner side of the bag for receipt of the pouch. The bottom ring 8 is shown attached via Velcro™ to allow easy securement of this ring within the lower part of the bag but alterative securement means may be provide, for example by sewing the ring to the net 4. Similarly, the upper ring may also be attached via Velcro™ which would enable replacement of the rings if they were to become damaged through use. Figures 3 A and 3B of the accompanying drawings illustrate an alternative drainage filter according to the present invention. Identical features already discussed in relation to Figures 1A and IB are given the same reference numerals and only the differences will be discussed in detail. The filter 200 again comprises a cylindrical bag formed of a net material 4 made from knitted HDPE filament but the bag is only provided with a single foam ring 60 formed from a closed cell cross linked polyethylene produced by extrusion. The ring is deeper than the rings provided in the embodiment of Figures 1A and IB to enable sufficiently secure holding of the bag against the inner wall of the gully pot with a single ring. The ring 60 is sewn into the top of the bag, being sandwiched between the net material 4 and a more durable non-porous rubber material 120. This rubber material increases friction between the wall and the bag to enable it to hold more weight, as well as making the bag more durable. A pocket 14 is again provided at the base of the bag 200 containing a removable pouch 20. The pouch may be made from the same material as the bag, such as a net material and the pouch is provided with strips of material for absorbing chemical contaminants, such as hydrocarbons and oils. The bottom of the bag is provided with a small opening 18 to allow removal of the pouch 20 and the insertion of a fresh one. The top of the bag 200 is also provided with handles 18. Further modifications to the drainage filter may be made without departing from the principles embodied in the examples described and illustrated herein.

Claims

1. A gully filter comprising a bag formed of a porous material or mesh, the bag having at least one at least partially expandable support flange around a perimeter of the bag, wherein, in use, the flange is configured to press against an inner wall of a gully pot to retain the bag in position.

2. The gully filter as claimed in claim 1 wherein the filter comprises a cylindrical bag formed of a net material, preferably the net comprises knitted high-density polyethylene (HDPE) filament.

3. The gully filter as claimed in claim 1 or claim 2, wherein the at least one at least partially expandable support flange is annular, rectangular or triangular.

4. The gully filter as claimed in claim 1,2, or 3, wherein the expandable support flange is in the form of a bracket provided with a ratchet mechanism wherein the ratchet is configured to extend the perimeter of the bracket once in situ within the gully pot.

5. The gully filter as claimed in any one of claims 1 to 3, wherein the at least one expandable support flange comprises a sprung ring.

6. The gully filter as claimed in any one of claims 1 to 3, wherein the at least one expandable support flange is formed of a plastics or rubber material.

7. The gully filter as claimed in any one of claims 1 to 3, wherein the at least one expandable support flange is inflatable.

8. The gully filter as claimed in any one of the preceding claims, wherein the bag is provided with multiple, spaced apart expandable flanges to retain the bag in position in the gully pot.

9. The gully filter as claimed in any one of the preceding claims wherein the flange is comprised of an at least partially compressible material wherein the flange expands against the inner wall of the gully pot once in situ.

10. The gully filter as claimed in claim 9, wherein the bag is provided with at least one ring of an at least partially compressible material for providing the expandable flange, preferably wherein the ring is provided towards a mouth of the bag.

11. The gully filter as claimed in claim 10, wherein the bag is provided with a pair of rings being spaced apart to provide an upper support ring near to a top of the bag and a lower support ring near to a base of the bag.

12. The gully filter as claimed in any one of claims 9 to 11, wherein the expandable flange is formed of a foam material, having a small degree of compressibility.

13. The gully filter as claimed in claim 12, wherein the foam material is a closed cell cross linked polyethylene produced by extrusion.

14. The gully filter as claimed in any one of the preceding claims, wherein the at least one at least partially expandable support flange is attached to the bag by one of more of (i) being sewn into the material of the bag, (ii) adhered thereto and / or (iii) provided with fastenable straps for securing to the bag.

15. The gully filter as claimed in any one of the preceding claims, wherein at least the outer sides of the expandable support flange are provided with a reinforcement member of a stronger material than that of the flange and / or the material of the bag.

16. The gully filter as claimed in claim 15, wherein the reinforcement member comprises a non-porous material.

17. The gully filter as claimed in claim 16, wherein the material is selected from a polyurethane (PU) + fluorocarbon (FC) treated polyester fabric and a rubber.

18. The gully filter as claimed in any one of the preceding claims, wherein the filter bag is provided with an absorbent material for removing oils, hydrocarbons and other contaminants.

19. The gully filter as claimed in claim 18, wherein the absorbent material is selected from at least one of a polypropylene (PP) meltblown fabric and / or polypropylene (PP) / Acrylic electret needle punch.

20. The gully filter as claimed in claim 18 or claim 19, wherein the bag is provided with a pocket for receiving the absorbent material.

21. The gully filter as claimed in claim 20, wherein the pocket is attached to an inner surface of the bag or is provided at the base of the bag.

22. The gully filter as claimed in claim 20 or claim 21, wherein the absorbent material is provided within a removable pouch for receipt within the pocket, the pocket having an opening to allow removal of the pouch.

23. The gully filter as claimed in any one of the preceding claims, wherein the bag is provided with a handle or straps to aid its removal from a gully.

24. A method of installing a filter bag into a gully, the method comprising:providing a filter according to any one of the preceding claims;inserting the filter into a gully; andsecuring the at least one expandable flange within the gully by expanding, pressing or inflating the at least one flange against inner sides of the gully to engage the side of the flange with the sides of the gully to retain the bag in position.

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