CA2226475A1 - Oil trap for catch basin - Google Patents

Abstract

An oil trap for a catch basin comprises a continuous trough which contains one or more oil-absorbing socks and has a plurality of holes formed through its bottom. The trough is adapted to be mounted in a catch basin so that a substantial portion of the water entering the catch basin will fall into the trap and come into contact with the oil absorbing socks before it drains out of the trap. When the water comes into contact with the socks, oil contaminants contained in the water are absorbed by the socks, such that the water leaving the trap contains less oil contaminants than when it entered the trap.

Description

CA 0222647~ 1998-01-08 OIL TRAP FOR CATCH BAS IN

The present invention relates to devices for trapping and removing oil contaminants from water which flows into catch basins and other drainage openings.

The flow of water contaminated with oil into storm sewers and other drainage systems poses an important environmental concern. In various regions, regulations and by-laws have come into force which prohibit the discharge of water cont~;n;ng oil and grease into storm sewers. One common source of contaminated water in storm sewer systems is untreat:ed water which flows into such systems through catch basins. As referred to herein, catch basins are substantially vertical shafts which are provided to permit water and other fluids to drain into storm sewer systems and other drainage systems or water storage systems. Catch basins are often square or rectangular in plan view, and are usually covered with a steel grate.

Catch basins are generally provided in or near parking lots and other paved surfaces in order to provide drainage for water generated on such surfaces from rain and from other sources. Often, water which drains into catch basins frc,m paved surfaces is contaminated with oil. The contamination can occur in various ways. For example, motor oil, grease, transmission fluids and other oil-based materials are frequently (and often inadvertently) deposited on paved surfaces everyday by the vehicles which pass over and stop on such surfaces, and these pollutants are pickecl up by water which comes into contact with the paved sur~aces. Additionally, water which comes into contact wi-th vehicles, such as water used to wash vehicles, often becomes contaminated with oil. The problem of oil-contaminated surface drainage water is exacerbated when the surface is near an area such as a gas station, a place where vehicles are washed, or other industrial settings.

~ CA 0222647~ 1998-01-08 ~.

In the past, various devices have been proposed for the purposes of containing oil spills and oil-contaminated water. For example, U.S. Patent No. 5,547,312 issued Auc3ust 20, 1996, to J. Schmitz Jr. describes an apparatus for use with a sump for containing run-off produced after washing vehicles. However no means for trapping and removing oil contaminants from water is disclosed.

10I~.S. Patent No. 5,181,802 issued January 26, 1993, to N. Thengs et al. describes an oil collector that can be used to combat oil spills and that uses an oil-absorbent material that is encased within a plurality of parallel cylindrical stockings that form a mat which can 15then be ro:Lled up to form a section of a boom.

rJ.s. Patent No. 4,798,754 issued January 17, 1989 to L.S. Tomek describes an oil absorbent floor mat designed to be placed under a motor vehicle or a machine. U.S.
20Patent No. 5,020,638 issued June 4, 1991 to P.N. Smith describes a device for catching liquids dripping from a vehicle which comprises a tray, an absorbent pad and a bag assembly for containing the pad.

25None of the above patents appear to disclose a device that is capable of removing oil based contaminants from water which flows into catch basins. Thus, a device which can remove at least some oil contaminants from water which flows into a catch basin is desirable.
It is an object of the present invention to provide an inexpensive oil trap for a catch basin or similar structure installed in the ground, this trap containing an oleophilic substance.
It is a further object of the invention to provide an oil trap that comprises a trough structure, CA 0222647~ 1998-01-08 including ~ bottom and inside and outside walls, and an oil absorbing substance received by the trough.

In accordance with one aspect of the invention there is provided an oil trap for a catch basin or similar structure installed in the ground. The oil trap comprises a continuous trough extending around a central opening.
The trough has a bottom, an inside wall extending substantially upwards from the bottom and an outside wall extending substantially upwards from the bottom and spaced from the inside wall. The bottom has a plurality of holes formed therethrough for permitting fluids to drain from the trough. The trough is mountable within a catch basin or similar st;ructure so that during use thereof at least a portion of the fluids entering the catch basin or similar structure will enter the trough. An oleophilic substance is receive~d within the trough and extends substantially the length of the trough such that in use at least a portion of the fluids that enter the trough will come into contact with the oLeophilic substance and be absorbed thereby.

Preferably, the oleophilic substance is contained within at least one sock constructed from a fluid permeable material, the at least one sock being received within the trough. Additionally, a fluid permeable rigid guard can extend between the inside wall and the outside wall of the trough over the at least one sock for substantially the length of the trough to provide protection for the at least one sock.
According to another aspect of the invention, an oil trap for a catch basin or similar structure to be installed in the ground comprises an upwardly opening continuous trough member defined by an upwardly extending inside wall, an upwardly extending outside wall, and a bottom extending between said inside wall and said outside wall. The trough has a number of holes formed CA 0222647~ 1998-01-08 therethrough, and the trough is moun1able in a catch basin so that at least a portion of the fluids entering the catch basin wil] pass through the trough. At least one sock containing an oil absorbing substance is received by the trough such that the oil absorbing substance is distributed substantially along the length of the trough.

Preferably, the oil trap is combined with a catch basin. The oil trap can be mounted within the catch basin adjacent a top thereof, wherein the oil trap has external horizontal dimensions corresponding closely to internal horizontal dimensions of the catch basin so that the outside wall of the trough member runs substantially parallel to and less than 1.5 inches from adjacent walls of the catch basin. Conveniently, a sealant can provide a waterproof seal between the outside wall and the adjacent walls of the catch basin.

According to a further aspect of the invention, an oil trap for installation in a catch basin or a similar below growld structure comprises atrough extendingabout and defining an open area and having a bottom, an inside wall extending substantially upwards from an inner side of the bottom, and an outside wall extending substantially upwards from an outer side of the bottom and spaced from the inside wall. The trough has holes formed therein for permitting water to drain from the trough and the trough is mountable within the catch basin or similar structure in order to catch at least a portion of fluids entering the catch basin or similar structure through a top end thereof.
The trap t~lso comprises an oil and petroleum absorbing substance received within and extending along the trough and supporl_ed thereby. Preferably, the trough has several sides that extend around the open area and the absorbing substance is contained within at least one sock constructed from a fluid permeable fabric. An open top of the trough can be covered by a substantially rigid mesh in order to - -CA 0222647~ 1998-01-08 .

protect the at least one sock and the absorbing substance therein.

Further ~eatures and advantages will become apparent from the following detailed description of the preferred embodiment!; taken in conjunction with the accompanying drawings.

In the drawings, Figure 1 is a top view of an oil trap constructed in accordallce with the invention;

I?igure 2 is a side elevation of the oil trap of Figure 1;
E?igure 3 is a bottom view of the oil trap of Figure 1;

E?igure 4 is a perspective view of a corner section of the oil trap of Figure 1;

E?igure 5 is a perspective view of a straight section of the oil trap of Figure 1;

E?igure 6 is an elevational view in cross-section showing the oil trap mounted in a catch basin, the cross-section of the oil trap being taken along the line VI-VI of Figure 1; ~nd E?igure 7 is a top view of an oil trap constructed in accordallce with a further embodiment of the invention.

Referring to Figure 1 and Figure 2, an oil trap device in accordance with the present invention is indicated qenerally by the arrow 10. The oil trap device 10, which can be installed in a conventional catch basin, includes a trough portion 12, one or more oil absorbing , CA 0222647~ 1998-01-08 socks 48, and optionally, a mesh guard 50. The trough 12 is a continuous trough with four sides 14, 16, 18 and 20.
Each side of the trough includes an outside, vertically extending wall 22, and inside, vertically extending wall 24 and a horizontally extending bottom 26. The inside wall 24 defines a central opening 66.

Referring to Figure 3, which shows a bottom view of the trough 12, a large number of apertures or holes 28 extend through the bottom 26 of the trough 12. As will be explained in greater detail below, the numerous holes 28 are provided to permit water to drain through the bottom 26 of the trough 12. Conveniently, the holes 28 may be circular :in form and approximately 3/16 of an inch in diameter.

~ eferring now to Figures 1, 4 and 5, one embodiment of the trough 12 will hereinafter be described.
In a preferred embodiment, the trough 12 is comprised of four ident;ical corner trough sections, one of which is indicated by the arrow 30 in Figure 4, and four identical straight trough sections, one of which is indicated by the arrow 32 :in Figure 5. The corner sections 30 and the straight sections 32 can be formed from a suitable rigid plastic, ;uch as PVC. In order to allow the corner sections 30 and the straight sections 32 to be connected together, each corner section 30 includes two connecting members 34 which are integrally attached to two ends 35 of a corner trough member 36. The connecting members 34 are dimensioned to slidably receive an end 41 of a straight section 32 and snugly engage the outer surface of the received end 41. Preferably a silicone sealant and/or bonding agent is placed between the inside surface of the connecting member 34 and the outside surface of the received end 41 of a straight section 32 to strengthen the joint between the two and also to make the joint impermeable to water. The connecting members also include CA 0222647~ 1998-01-08 downwardly opening channels 38 for engaging the upper edges 40 of the inside and outside walls of the received end 41 of the straight section. When the end 41 of the straight section 32 is received by the connecting member 34, the inside surface 42 of the straight section 32 is substantially flush with the inside surface 37 of the corner portion 36.

Each straight section 32 includes elongate ribs 46 extending along its inside surfaces below and parallel to the top peripheral edges 40 of the straight section 32.
The ribs ~16 serve to strengthen the straight section 32.
In one pre~erred embodiment the top edges of the inside and outside wc3.11s of the straight section are approximately 4.25 inch,es (11 centimetres) apart and the trough is approximat~31y 2 inches (5 centimetres) deep.

Referring to Figures 1 and 2, in combination with the trough portion 12, the oil trap of the present invention comprises one or more oil absorbing, elongate flexible socks or tubes 48 which are laid along and received within the trough 12. The socks 48 extend the entire perlmeter or for most of the perimeter of the trough 12 and have a transverse cross-sectional area slightly less than the area defined by the inside surfaces of the trough 12 such th,at fluids entering the trough 12 will generally come into contact with the socks 48 before draining out of the trough 12. In the embodiment of the invention illustrated in the figures, two socks 48 are received within the trough member 12.

The socks 48 are comprised of a liquid permeable flexible fabric shell which is stuffed with a substance having o]eophilic and hydrophobic properties. One oleophilic and hydrophobic substance that is suitable for use in the socks 48 is 3M Brand Oil Sorbent (trade-mark).

CA 0222647~ 1998-01-08 The oil trap 10 of the present invention optionally can include a plurality of substantially rigid mesh guards 50 which are placed over the four sides 14, 16, 18 and 20 o~ the trough 12 to protect the socks 48 ~rom sticks, stones and other debris that may fall onto the trap 10. In the embodiment illustrated in the figures, four elongate mesh guards 50 are provided. The guards 50 are each made of a resilient elongated section of galvanized metal mesh or rigid plastic mesh and have a semi-cylindrical shape which permits the guards 50 to beinstalled on the sides 14, 16, 18 and 20 of the trough 12 over the tubes 48. When the mesh guards 50 are installed on the trough 12, their elongate edges rest against and are supported by the inner surfaces of the inside walls 24 and outside wLlls 22 of the trough 12. Preferably, the transverse distance between the two elongate edges o~ each mesh guard 50 is such that the guards 50 must be compressed slightly to install them on the trough 12 so that once the guards 50 are installed, their elongate edges are urged outwards against the walls of the trough 12. The force of the edges of the guards 50 along the walls of the trough 12 aids in keeping the guards 50 in place, yet permits them to be easily removed so that the oil absorbing socks 48 can be removed and replaced or cleaned when necessary.
~ s mentioned above, the oil trap 10 of the present invention is designed to be mounted in a catch basin. Referring to Figure 6, a cross-sectional view of the oil trap 10 mounted in a conventional catch basin 52 is shown. The catch basin 52 includes a cover grate 54 which is level w:ith the surrounding ground 56, and which includes a series c\f elongate parallel openings 58 through which water can drain into the catch basin 52. The catch basin 52 comprises a vertical, square shaft which may lead to a storm sewer system.

CA 0222647~ 1998-01-08 The oil trap 10 is mounted in the catch basin 52 such that the mouth of the continuous trough 12 opens upwards and lies in a generally horizontal plane. The trap 10 i~; preferably mounted so that it is a few inches below the bottom of the catch basin cover S4. In one preferred embodiment, the top of the trap 10 is located about six inches below the adjacent ground level 56. The dimensions of the outer perimeter o~ the oil trap 10 are such that the outside walls 22 of the trough 12 are snugly received by the walls 60 of the catch basin 52.
Preferably, any gap which is present between an upper peripheral edge 64 of the outside wall 22 and the walls 60 of the catch basin 60 is less than 1.5 inches (3.81 centimetre3). A silicone sealant may be placed around the junction formed between the top peripheral edge 6~ of the outside wall 22 and the walls 60 of the catch basin 52 in order to ~;eal any gaps and ensure that fluid that flows along the walls 60 flows into the trap 10.

E3rackets are preferably used to mount the oil trap 10 iirl a catch basin. In the embodiment shown in Figure 6, eight L-shaped brackets 62, which are fastened two per side to the concrete walls 60 of the catch basin 52, support the underside of the trough 12. The L-shaped brackets 62 can be fastened to the concrete walls of the catch basin 52 in a variety of different ways. In one preferred ~embodiment, the L brackets 62 are mounted to the walls 60 by charge-driven concrete nails. The brackets 62 could alternatively be attached to the wall 60 by self-tapping concrete screws set in predrilled holes, or by screws att~ched to anchors which have been inserted into predrilled holes. A suitable adhesive could also be used.
The L bra~kets 62 can, if desired, be attached to the bottom of the trough 12 by bolts secured with nuts, said bolts passing through predrilled holes provided through the bottom 26 of the trough 12. In the alternative, it can simply res-t; on the brackets, thus permitting the trap to be CA 0222647~ 1998-01-08 removed easily from the catch basin.

Referring to the figures, the operation of the oil trap 10 of the present invention will now be described.
As mentioned above, catch basins such as the catch basin 52 illustratecL in Figure 6 are often located in or near parking lots and other paved surfaces in order to provide drainage for water generated on the surfaces, either by rain or from other sources. The water entering the catch basin 52 will often be contaminatecL with oil and grease which has been deposited on a paved surface in a variety of ways, such as from dripping oil pans and leaking transmissions, or from oil which has been washed off cars and other vehicles. The oil trap 10 of the present invention is provided to remove at least some of the oil cont~m; n~n~s from at least some of the water which enters the catch basin 52.

It will be appreciated that water entering the catch basin 52 from the surrounding surface 56 will generally enter the catch basin 52 by falling downwards into the bc~sin at or near the edges of the opening that is defined by the basin. In other words, water entering the catch basin 56 will generally enter the basin at or near the top ecLges of the walls 60 of the basin. As such, a large perc,entage of the water flowing into the catch basin 52 will flc)w downwards along the walls 60, or within a few inches of the walls 60, especially near the top of the basin. As the trough 12 of the trap 10 generally extends outwards from the walls 60 of the basin (approximately 4.25 inches (11 centimetres) in one preferred embodiment), a large percentage of the water entering the catch basin 52 will generally pass through the mesh guards 50 and into the oil trap 10.
~!~ost of the water entering the oil trap 10 will come into contact with the oil absorbing socks 48 before CA 0222647~ 1998-01-08 . ~ .

the water can drain out of the trap 10. The water may come into contact with the socks 48 by landing right on top of the socks 48 after passing through the mesh guards 50.
Additionally, water in the trough 12 can come into contact with the socks 48 while it is waiting to drain out of the trough 12. As mentioned above, the socks 48 contain a material which is both oleophilic (oil loving) and hydrophobic (water repelling), meaning that the socks 48 have a very high absorbed oil/absorbed water ratio. As a result, much of the oil and grease which contaminate water that comes into contact with the socks 48 will be separated from the water and absorbed or trapped by the socks 48. At the same t:ime, very little water will be absorbed by the socks 48. Thus, water leaving the trap 10 will generally contain less oil contaminants than water entering the trap 10 .

Water which enters the trap 10 will generally leave the trap by f lowing out of the trough 12 through the plurality c)f holes 28 which are located in bottom 26 of the trough 12. However, during periods of continued heavy water f low, such as a rain downpour, the f low of water out through the holes 28 may not equal the f low of water into the trough 12, and the level of water in the trough 12 will rise to a point where it flows over the top edge of the inside wal:L 24 of the trough 12, through the large hole 66 and down into the storm sewer. It also is possible that some water entering the catch basin 52 may by-pass the oil trap 10 completely and go straight down the hole 66 without ever coming into contact with the socks 48, especially during periods of heavy rain. However, the hole 66 is normally required to ensure that during periods of heavy water f low the catch basin 52 will not become backed up as a result of the trap 10.

The socks 58 of the trap 10 periodically have to be removed so that they can be cleaned and then replaced, CA 0222647~ 1998-01-08 -or replace~ with new socks 58. In order to maintain the trap 10, the cover 54 of the catch basin 52 is opened, the mesh guards 50 are removed from the trap 10, the socks 58 are then removed ~rom the trough 12 and replaced with either clean or new socks, the mesh guards 50 are replaced, and then the cover 54 is closed. The frequency with which the socks 58 have to be cleaned (which involves draining the absorbed oil from the socks) or replaced will depend on the degree of oil contamination affecting the water which passes through the trap 10 and the amount of contaminated water that enters the catch basin.

If desired, an additional mesh guard 68 (see Figure 7) c~an be placed over the centre hole 66 of the trap 10 to stop sticks and other debris from entering the storm sewer system. The peripheral edges of the guard could rest on the upper edge of the inside wall 24 of the trough 12.
The mesh guard 68 can also be installed directly below the centre hole 66 with its edges on all four sides resting on the brackets 62. Alternatively the mesh guards 50 and the centre mesh guard 68 could be replaced with a single guard that covered the whole oil trap 10.

It will thus be appreciated that the oil trap 10 of the present invention can be installed in a catch basin to assist in removing oil contaminants from water entering the catch basin. Although the oil trap 10 illustrated in the figures and described above is square, it will be appreciated that the trap could be rectangular or round or a variety of other shapes in plan view to accommodate different catch basin sizes and shapes. Additionally, the trap could be used in drainage openings other than catch basins, such as manholes, particularly manholes with covers or tops that are not sealed. The trough 12 could be constructed in a variety of ways other than that disclosed above, for example, the trough could be semi-cylindrical in cross-section. The trough could be formed from one or more " CA 0222647~ 1998-01-08 .
~.

pieces of galvanized steel or the trough could be formed from a unitary piece of resilient vinyl or plastic material. The dimensions of the trough and the holes therethrough could be varied to best fit the specific location and application of the trap. Additionally, the oleophilic and hydrophobic material placed in the trough 12 need not necessarily be contained in socks. For example, the material could be contained in mats which are rolled up and then placed in the trough 12.
While various embodiments of this invention have been illustrated in the accompanied drawings and described above, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the essence of this invention. All such modifications or variations are believed to be within the scope of the invention as defined by the claims appended hereto.

Claims (19)

1. An oil trap for a catch basin or similar structure installed in the ground comprising a continuous trough extending around a central opening and having a bottom, an inside wall extending substantially upwards from said bottom and an outside wall extending substantially upwards from said bottom and spaced from said inside wall, said bottom having a plurality of holes formed therethrough for permitting fluids to drain from said trough, said trough being mountable within a catch basin or similar structure so that during use thereof at least a portion of the fluids entering the catch basin or similar structure will enter said trough; and an oleophilic substance received within said trough and extending substantially the length of said trough such that in use at least a portion of the fluids that enter said trough will come into contact with said oleophilic substance and be absorbed thereby.

2. An oil trap according to claim 1, wherein said oleophilic substance is contained within at least one sock constructed from a fluid permeable material, said at least one sock being received within said trough.

3. An oil trap according to claim 2, including a fluid permeable rigid guard extending between said inside wall and said outside wall of said trough over said at least one sock for substantially the length of said trough to provide protection for said at least one sock.

4. An oil trap according to any one of claims 1 to 3, including a silicon sealant for forming a water impermeable seal between said outside wall and the catch basin when said trough is mounted within the catch basin.

5. An oil trap according to any one of claims 1 to 4, including a fluid permeable rigid mesh guard extending across a central opening defined by said inside wall of said trough.

6. An oil trap according to any one of claims 1 to 5, wherein said holes are circular and have a diameter of less than 0.25 inches.

7. An oil trap according to any one of claims 1 to 6, wherein said trough is square in plan view and said oleophilic substance is also hydrophobic.

8. An oil trap for a catch basin or similar structure to be installed in the ground comprising:

an upwardly opening continuous trough defined by an upwardly extending inside wall, an upwardly extending outside wall, and a bottom extending between said inside wall and said outside wall, said trough having a number of holes formed therethrough, said trough mountable in a catch basin so that at least a portion of the fluids entering the catch basin will pass through said trough; and at least one sock containing an oil absorbing substance received by said trough such that said oil absorbing substance is distributed substantially along the length of said trough.

9. An oil trap according to claim 8, further including a plurality of bracket members adapted for mounting said trough in the catch basin or similar structure.

10. An oil trap according to claim 8, further including a plurality of rigid fluid permeable guards extending over said socks between said inside wall and said outside wall.

11. An oil trap according to any one of claims 8 to 10, wherein the trough is comprised of a rigid vinyl material.

12. The combination of a catch basin and an oil trap according to claim 8 or 10, said oil trap being mounted within said catch basin adjacent a top thereof, wherein said oil trap has external horizontal dimensions corresponding closely to internal horizontal dimensions of said catch basin so that said outside wall of the trough member runs substantially parallel to and less than 1.5 inches from adjacent walls of the catch basin.

13. The combination of claim 12 wherein a sealant provides a waterproof seal between said outside wall and the adjacent walls of the catch basin.

14. The combination of claim 12 or 13 wherein a plurality of brackets are rigidly mounted to the walls of the catch basin and said trap is supported by said brackets.

15. An oil trap for installation in a catch basin or a similar below ground structure, said trap comprising:

a trough extending about and defining an open area and having a bottom, an inside wall extending substantially upwards from an inner side of the bottom, and an outside wall extending substantially upwards from an outer side of the bottom and spaced from said inside wall, said trough having holes formed therein for permitting water to drain from said trough, said trough being mountable within said catch basin or said structure in order to catch at least a portion of fluids entering the catch basin or said structure through a top end thereof;
and an oil and petroleum absorbing substance received within and extending along said trough and supported thereby.

16. An oil trap according to claim 16 wherein said trough has several sides that extend around said open area and said absorbing substance is contained within at least one sock constructed from a fluid permeable fabric.

17. An oil trap according to claim 16 wherein an open top of the trough is covered by a substantially rigid mesh in order to protect said at least one sock and the absorbing substance therein.

18. An oil trap according to any one of claims 15 to 17 wherein said trough and said open area are both square in plan view and said absorbing substance is also hydrophobic.

19. An oil trap according to any one of claims 15 to 18 wherein said trough is made of a rigid plastic material and said trap includes bracket members for mounting said trough inside said catch basin or said structure.