WO2008099182A1

WO2008099182A1 - Surface water drainage

Info

Publication number: WO2008099182A1
Application number: PCT/GB2008/000515
Authority: WO
Inventors: Faisal Abdulaziz Alasfour
Original assignee: Barry, Patrick, James
Priority date: 2007-03-21
Filing date: 2008-02-14
Publication date: 2008-08-21

Abstract

A drainage pit for use at the side of a roadway, etc., as a receptacle for collecting solid matter from rainwater entering the pit, but which allows the rainwater to pass out of the pit. A funnel collects surface water entering the pit and guides it into the receptacle. The receptacle is provided with drainage holes. The receptacle has an inner basket which collects matter, such as leaves for example, and stops any drainage holes in the receptacle from blocking. The receptacle can be removed from the pit to empty the solid matter therein, and a door in the bottom of the receptacle is provided for the purpose. The grating covering the pit has openings with sloping sides so that the lower end of the opening is wider than the upper, with the result that material does not collect in the openings of the gratings blocking them.

Description

SURFACE WATER DRAINAGE

The present invention relates to surface water drainage pits .

Surface water drainage pits are commonly found at the side of roadways, but may be found in other locations, for example, in car parks, airport runways and so on. They are- provided to drain the surface of water, most commonly rainwater.

The pit can also be called a gully (e.g. in the UK), or a storm drain (in the US) . They are usually covered by a metal grating (to support traffic) and have one or more openings connecting the pit to a surface water drain. (A typical configuration is that the drain passes into the pit at one opening and then out and onwards via another.) Surface water enters the pit via the grating and then flows from there into the surface water drain; from there it flows on via the sewerage system to an outflow into a pond or river for example. (If the sewerage is combined with foul water the destination will more likely be a treatment works . )

A problem, illustrated in Figure 1, with such drainage pits is that they can become blocked with silt or sand or other matter that flows into the pit along with the surface water. The pits and neighbouring sections of drain therefore have to be cleaned out at regular intervals.

US2007/0199869A1 discloses an improved drainage pit (or "basin") . Figure 2 shows a cross section thereof.^' The pit has a removable receptacle that receives the surface water, but at least some of the detritus that it brings with it collects in the bottom of the receptacle. The receptacle contains an inner housing having walls forming a central pipe down which the surface water flows from the grating to the bottom of the receptacle. The walls of the central pipe are spaced from those of the receptacle to form a channel. The lower end of the central pipe is above the bottom of the receptacle and a flange between the inner housing and the receptacle at the lower end of the central pipe is provided with holes communicating with the channel . The surface water flows from the bottom of the receptacle up through the channel and then passes out of the receptacle through horizontal slits in the walls of the receptacle. The walls of the receptacle are spaced from those of the pit providing a further channel down which the surface water passes to the bottom of the pit, from where it flows into the drain. The bottom of the receptacle is spaced from bottom of the pit to provide a large passage for the surface water to reach the drain. The construction is said to be of particular usefulness in sandy areas. The ^'sand collects in the bottom of the receptacle filling up past the holes in the flange. The surface water passing through the sand is thereby filtered. With prolonged use the receptacle fills further with sand and can then be emptied by simply lifting the receptacle out of the pit.

According to the invention there are provided drainage pits, solid matter collection receptacles, funnels and gratings as defined in the appended claims.

Examples of the invention will now be described, with reference to the accompanying drawings, of which: FIGURE illustrates a problem with conventional drainage pits; FIGURE is a cross section of the drainage pit disclosed by US2007/0199869A1; FIGURE is a cross section of a first example of the invention; FIGURE is a plan view of the first example of the invention; FIGURE shows the first example filled with solid matter to a certain point; FIGURE illustrates further examples of the invention; FIGURE is an example of the invention particularly suited to small gullies;

FIGURE 8A shows a conventional grating; and FIGURE 8B shows a grating in accordance with the invention.

Figure 3 shows a first example of the invention in cross section. A drainage pit 10 in the ground 11 (typically 90cm across) is provided with a grating 12 at the level of the surface 13 of the ground. A receptacle 14 is provided in the pit to catch surface water entering the pit via the grating. Water overflowing from the receptacle flows over a lip 15 of the receptacle and passes down a channel 16 between the wall 18 of the receptacle and the wall 19 of the pit. From there it enters the surface water drain 17 where that opens into it. Solid matter 8 in the water settles in the receptacle and stops it from entering the drain 17, which therefore remains unobstructed. The pit can be easily cleaned by opening the grating 12 and lifting out the receptacle, which can then be emptied by tipping out the contents (for example into a large receptacle mounted on a vehicle so that the solid matter can be removed from the site) .

As shown in Figure 4, which is a plan view of the pit containing just the receptacle, the receptacle 14 is rectangular in shape and is located generally in the centre of the pit 10 spaced from the walls 19 thereof by spacers 7 attached to the wall 18 of the receptacle near the lip in the centre of each side of the receptacle. The spacers, not being wide, do not particularly restrict the channel 16.

Each wall of the receptacle 18 has a section 6 reducing the width of the receptacle to broaden the width of the channel 16 to about 20cm to allow for free flow of the water; the channel width at the lip 15 is about 10cm, which is still sufficient but the receptacle is wider here to allow as much room as possible for a funnel 24.

The floor 20 of the receptacle is provided- with spacers 21 to raise it above the floor 22 of the pit providing another channel 23 below the receptacle allowing surface water to reach the drain 17. (Alternatively the spacers are provided on the floor of the pit or as a separate item.)

A funnel 24 is mounted below the grating 12 to guide the surface water to the receptacle 14. The mouth 25 of the funnel is positioned to collect water from all the openings 26 of the grating. The grating 12 and mouth of the funnel are preferably wider than the receptacle in order to maximise the total area of the openings 26 between the bars 27 of the grating so that the grating does not restrict the flow of the surface water. This design also allows the receptacle and funnel to be retrofitted to existing gullies.

In this example the funnel is mounted by having an outer horizontal flange 28 at its mouth that rests on the top of the wall 19 of the pit and which is sandwiched between that and the grating. For cleaning the funnel is lifted out first before the receptacle is lifted out of the pit.

An alternative is to mount the funnel (in the same position above the receptacle) to the receptacle using one or more brackets . The funnel and receptacle are then lifted together out of the pit for emptying and cleaning.

The stem 29 of the funnel opens at a position where the surface water will flow into the receptacle. Preferably, as shown in Figure 3 the opening 30 of the stem is at a level distance D below the lip 15 of the receptacle since that discourages, when the receptacle is full, immediate flow of the water across the surface of the water in the receptacle and over the lip before the solid matter has had a chance to settle out. There is however a compromise to be made in the length of the stem; the flow of surface water will become blocked when the solid matter in the bottom of the receptacle reaches the level of the opening 30 of the stem. Figure 5 shows the receptacle filled with solid matter to beyond the point where the channel 31 is blocked and the maximum flow rate through the gully is severely reduced. Therefore the longer the stem the more frequently the receptacle will need to be emptied.

Preferably as shown the stem descends (distance D) only a few centimetres below the level of the lip. Preferably distance D is 10cm or less. Figure 6 is a cross section of a second example of the invention. This is generally similar to that of Figures 3 to 5, except as described below. Also to simplify the illustration the pit and grating are not shown.

In the example of Figures 3 to 5 the walls of the receptacle and the funnel do not allow water to pass through them. In the example of Figure β the walls 18 of the receptacle 14 are provided with holes 40, 41 to allow the water in the receptacle to drain. This provides several further advantages. With most of the water drained from the receptacle its weight is reduced making it easier to lift out of the pit, and also the material tipped out of the receptacle is therefore mostly solid meaning that the water does not have to be transported away from the site. During periods when there is no rain the solid material is more likely to dry out preventing it rotting (if it contains organic matter) , thereby reducing unpleasant smells.

The size of the holes may be chosen in relation to the size of the particles in the surface water likely to be found in a particular location, so that they are retained in the receptacle. (Smaller particles that escape are more likely to be carried along by the water through the drain without blocking it.)

In this example there are two kinds of holes are provided. A dozen or so 3mm holes 40 are provided in the lower half of each wall with six being just a few cm above the floor 20 of the receptacle. These allow the receptacle to drain in several hours, the time depending on the solid contents of the receptacle. A large mesh of 3mm perforations 41 are provided in the portion of the walls of the receptacle above the holes 40. Under low surface water flow conditions the holes 40 are sufficient to drain the receptacle. At higher flow rates the level of the water in the receptacle rises reaching the mesh of holes 41, which allow a much higher flow to pass through them. In this state the separation out the solid matter will be less effective, but it is a priority to ensure that the pit drains the surface of the ground.

At even higher flow rates, or when the receptacle has significantly filled with solid matter, the level of the water may reach the top of the receptacle and then the water flows over the lip 15 of the receptacle as with the example of Figures 3 to 5.

Holes 42 are also provided in the stem 29 section of the funnel; in the example as shown these are in the form of a mesh of 3mm perforations. The stem 29 preferably has these on all sides. (In the cross section that is Figure 6 the far wall of the stem 29 of the funnel has been omitted to simply the view.)

In normal operation the holes 42 do not reduce the effectiveness of the funnel's function of guiding the surface water into the middle of the receptacle. When the solid matter collected in the receptacle reaches the level of the opening 30 of the stem blocking the channel between the stem and the receptacle, the holes 42 in the stem nonetheless allow the flow of surface water to reach the drain 17, the water flowing through the holes 42 in the stem and then over the lip 15 of the receptacle. An example in which holes are provided in the funnel but not in the receptacle is also possible. In this example the water flows as described for the example of Figures 3 to 5 until the solid matter reaches the opening 30 of the funnel and then it flows as described for the first example described above in relation to Figure 6.

The Figure 6 shows some further features which can be provided in examples of the invention.

Α door 25 is provided in the floor 20 of the receptacle.

Once the receptacle has been lifted out of the pit for cleaning this is opened to empty out the solid matter.

This avoids having to tip the receptacle to empty it. (A door can be provided whether or not the receptacle has drainage holes . )

In a further example the receptacle is provided with an inner basket 50. In Figure 6, this is shown lifted out from inside receptacle 14, but in use is normally located inside the receptacle. The basket is sized to give a clearance of a few centimetres between the walls of the basket and the walls 18 of the receptacle. Preferably, the walls of the basket are constructed from 3 cm mesh 51. This is particularly suitable for retaining items such as leaves and plastic bags that would otherwise block the holes 40 and 41 of the receptacle. A lower portion 52 of the walls of the basket is preferably a mesh of 3 mm perforations. These stop smaller particles from blocking the holes 40, but if they themselves become blocked flow is still achieved through the larger mesh 51. Whilst the basket 50 can be lifted out and cleaned by tipping up, it too is preferably provided with a door 53 in its floor, which can be opened in order to release the solid matter that it contains. The basket 50 may be mounted inside the receptacle 14 in various ways. Whilst the basket could be permanently fixed, it is preferably removable, and a fitting to achieve that is shown in Figure 6. The top rim of the basket is provided with a funnel section 54 having a horizontal flange 55. The horizontal flange 55 rests on the flange 28 of the main funnel 24 and is sandwiched between that and the grating 12.

The inner basket 50 is particularly useful where the receptacle 14 has drainage holes, but could still, if ^• desired, be used if the receptacle does not have drainage holes ;

As shown in Figure 6, the receptacle, with or without drainage holes, can be provided with a hanger 60. This comprises two vertical rods 61 fixed to the middle of two opposite sides of the receptacle 14, and spaced a few cm therefrom, by a vertical box section member (not shown) . Each rod 61 has an eye at its top end at a level just above the lip 15, for connection, when it is desired to lift the receptacle, to lifting hooks 63. The rods are also each provided with hooks 64 attached to them at a suitable height just below the opening 30 of the stem of the funnel. These hooks 64 extend horizontally across the funnel stem wall and engage therewith when the rods are lifted, lifting the funnel out of the pit.

In the examples above, the funnel 24 has sloping sections extending beyond the receptacle on all sides . In smaller gullies, this may not leave much room to give the receptacle much volume . An example particularly suited to smaller gullies is shown in Figure 7. Here, the funnel 24 only has a sloping section 70 on one side of the receptacle 14. The funnel still preferably has the flange 28 on all sides, which ensures that the funnel collects water from all the openings 26 of the grating 12. The receptacle 14 is not positioned in the centre of the pit but its wall on the opposite side from the sloping section 70 of the funnel is placed against the wall of the pit. Underneath the sloping section 70 of the funnel the wall of the receptacle is provided with a long sloping section 71 in order to increase the volume of the receptacle.

In this example, the funnel and receptacle are provided as a single integral item with at least one wall of the receptacle (the left-hand wall 72 in Figure 7) merging into the wall of the stem section of the funnel .

This example can also be provided with drainage holes in the receptacle and/or mesh and may optionally also have an inner basket, as in the examples of Figure 6.

Figures 8A and 8B illustrate a further aspect of the invention. A conventional grating 12 is shown in cross- section in Figure 8A. The bars 27 of the grating 12 have vertical walls, and sand or other solid material 80 often blocks the opening 26 between them, requiring them to be cleaned by poking the material down into the pit with a rod.

An improved grating in accordance with the invention is shown in cross-section in Figure 8B. In this, the bars 27 have sloping sides so that the width of the openings 26 is greater at the bottom than at the top. With this shape, solid material 80 cannot become wedged in the openings, which therefore remain clear. Alternatively, one wall of each hole may be vertical and the other sloping, or even both walls of an opening can be sloping in the same direction (e.g., both from left to right), as long as the opening is wider at the bottom than at the top .

Claims

CLAIMS :

1 . A drainage pit comprising : a solid matter collection receptacle, and a funnel positioned to collect surface water entering the drainage pit and direct it into the receptacle .

2. A drainage pit as claimed in claim 1 wherein the receptacle has an upper opening that receives the surface water and the funnel has a mouth section extending horizontally beyond the perimeter of the upper opening of the receptacle .

3. A drainage pit as claimed in claim 2 wherein the mouth section extends beyond the perimeter of the upper opening of the receptacle on all sides.

4. A drainage pit as claimed in any one of claims 1 to 3 wherein the funnel has a sloping section on at least one side of the funnel but no sloping section on at least one other side of the funnel.

5. A drainage pit as claimed in any one of claims 1 to 4 comprising a grating at the upper end of the pit, the grating having openings to allow the influx of surface water .

6. A drainage pit as claimed in claim 5 wherein the openings of the grating cover an area extending horizontally beyond the perimeter of the upper opening of the receptacle.

7. A drainage pit as claimed in any one of claims 1 to 6 wherein the receptacle has a lip having a level to which the receptacle can fill with water and the funnel opens into the receptacle at a point below that level.

8. A drainage pit as claimed in claim 7 wherein the said opening point of the funnel is above half way between the bottom of the receptacle and the said fill level.

9. A drainage pit as claimed in claim 8 wherein the said opening point of the funnel is above 10 cm below the said fill level.

10. A drainage pit as claimed in any one of claims 1 to 9 wherein the funnel has a flange at its mouth that supports the funnel by resting on the wall of the pit.

11. A drainage pit as claimed in any one of claims 1 to 9 wherein the funnel is mounted on the receptacle.

12. A drainage pit as claimed in any one of claims 1 to 9 wherein the funnel is integral to the receptacle.

13. A drainage pit as claimed in any one of claims 1 to 12 wherein the funnel is provided with drainage holes.

14. A drainage pit as claimed in claim 13 wherein the funnel has a stem section and the drainage holes are provided in the stem section.

15. A drainage pit comprising: a solid matter collection receptacle, wherein the receptacle is provided with drainage holes.

16. A drainage pit as claimed in claim 15 wherein a wall of the receptacle has a lower region having a relatively low proportion of the area of the wall being hole and an upper region having a relatively high proportion of the area of the wall being hole.

17. A drainage pit comprising: a solid matter collection receptacle, and an inner basket disposed within the solid matter collection receptacle.

18. A drainage pit as claimed in claim 17 wherein the basket has a lower region having a relatively^' small holes and an upper region a relatively large holes.

19. A drainage pit as claimed in claim 17 or claim 18 wherein the basket is provided with door in its floor that can be opened to empty solid matter from the basket.

20. A drainage pit comprising: a solid matter collection receptacle, wherein the receptacle is provided with door in its floor that can be opened to empty solid matter from the receptacle.

21. A drainage pit comprising: a grating at the upper end of the pit, the grating having openings to allow the influx of surface water, wherein the said openings have opposing sides and at least one of those sides has a slope that makes the lower end of the opening wider than the upper end.

22. A drainage pit as claimed in claim 21 wherein one of the opposing sides slopes in one direction and the other slopes in the opposite direction.

23. A drainage pit as claimed in a combination of two or more of the preceding claims, each member of the combination being selected from a different one of the sets following sets A to E, set A comprising claims 1 to 14, set B comprising claims 15 to 16, set C comprising claims 17 to 19, set D comprising claim 20, set E comprising claims 21 to 22.

24. A solid matter collection receptacle for a. drainage pit having the features prescribed in any one of claims 1 to 16 or claim 20.

25. A solid matter collection receptacle for a drainage pit having the features prescribed in any one of claims.1 to 16 or claim 20 in combination with a funnel for a drainage pit having the features prescribed in any one of claims 1 to 16.

26. A solid matter collection receptacle for a drainage pit having an inner basket disposed within the solid matter collection receptacle. ■

27. A solid matter collection receptacle as claimed in claim 26 wherein the basket has a lower region having a relatively small holes and an upper region a relatively large holes .

28. A solid matter collection receptacle as claimed in claim 26 or claim 27 wherein the basket is provided with door in its floor that can be opened to empty solid matter from the basket

29. A grating for a drainage pit having the features prescribed in claim 21 or claim 22.