GB2475551A

GB2475551A - Drainage cell

Info

Publication number: GB2475551A
Application number: GB0920507A
Authority: GB
Inventors: Stuart Edward Alan Ramella
Original assignee: Polypipe Civils Ltd
Current assignee: Polypipe Civils Ltd
Priority date: 2009-11-23
Filing date: 2009-11-23
Publication date: 2011-05-25
Anticipated expiration: 2029-11-23
Also published as: EP2325403A2; EP2949826A3; GB2475551B; GB2486604A; EP2949826B1; EP3495575A1; GB201204123D0; EP2325403B1; EP2325403A3; GB201019852D0; EP2949826A2; GB0920507D0; GB2476534A; GB2476534B; GB2486604B

Abstract

The invention relates to a drainage cell (1 figure 1) for a ground water handling system, the cell comprising a through channel 25, one or more transverse members 5 extending from or adjacent the edge of the through channel 25 towards a base of the cell (1 figure 1) for deflecting, in use, particulates or debris carried in a fluid flowing in the through channel 25. Later embodiments relate to a drainage assembly comprising a plurality of the cells; and a drainage cell comprising an attenuation volume with a channel adjoining a boundary of the cell and fluidly connected to the attenuation volume.

Description

DRAINAGE CELL

The present invention relates to a drainage cell for a ground water or storm water handling system and particularly, but not exclusively, a drainage cell for removing silt and debris from water flowing through the cell.

Modern building and agricultural methods are such that water which would historically drain away by natural seepage is no longer able to do so, which leads to floods, soil erosion and the like.

As a consequence, water falling as rain or formed from melting ice or flooding cannot return to the ground to form ground water. Instead, it often flows away from a locality where it is generated, depriving the ground of its beneficial effects, and overflowing normal drainage systems. This can therefore lead to flooding or erosion for example.

It is known to provide a drainage cell, which can be installed underground and which comprises perforated boundary walls. A number of such cells may be modularly assembled to provide a system for ground water attenuation. Attenuation of the water is understood to mean that the period during which water is held at a location where it arises, for dispersal into the ground at that area without flowing away therefrom, is increased. Alternatively, the water dispersed into a piped drainage system at a controlled rate. In this way, the water is able to disperse into the ground at a more steady rate.

The present invention seeks to mitigate or at least ameliorate the disadvantages of the known devices.

According to a first aspect of the present invention, there is provided a drainage cell for a ground water handling system, the cell comprising a through channel, the cell comprising one or more transverse members extending from or adjacent the edge of the through channel towards a base of the cell for deflecting, in use, particulates or debris carried in a fluid flowing in said through channel.

According to a second aspect of the present invention, there is provided a drainage assembly, wherein the drainage assembly comprises a plurality of water attenuation cells including one or more drainage cells according to the first aspect of the invention.

According to a third aspect of the present invention, there is provided a drainage cell comprising an attenuation volume, the cell comprising a channel adjoining a boundary of said cell and being fluidly connected to said attenuation volume.

Preferred features of the present invention are defined in the dependent claims.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is side view of a cell of an embodiment of the present invention; Figure 2 is an exploded view of the cell of Figure 1; Figure 3 is a perspective view of a cell of Figure 1; Figure 4 is a perspective view of a cell of a further embodiment of the present invention; Figure 5 is a partially exploded view of the cell of Figure 4; Figure 6 is an exploded view of a cell of Figure 4; Figure 7 shows a half cell of a further embodiment of the present invention; Figure 8 is an exploded view of the embodiment of Figure 7; Figure 9 is an assembled view of the embodiment of Figure 7; Figure 10 is a cross section through the embodiment of Figure 7; Figure ills a detail view of the embodiment of Figure 7; Figure 12 is a cross section through the embodiment of Figure 7; Figure 13 is a cell of a further embodiment of the present invention; Figure 14 is an exploded view of the embodiment of Figure 13; and Figure 15 is a perspective view showing an embodiment of the cell of the present invention installed in a water handling system.

Figure 1 shows a cell generally at 1 of an embodiment of the present invention. The cell has the form of a parallelepiped. The cell I comprises two identical half-cells la, lb. Each half-cell comprises a base 2a, 2b. The longitudinal walls of each half-cell Ia, lb comprise a plurality of vertical support elements 3a, 3b, which extend from the base 2a, 2b of each half-cell la, lb. The vertical support elements 3a, 3b are hollow, which serves to reduce the weight of the cell and facilitates manufacture using injection moulding techniques, for example. The vertical support elements 3a, 3b have a D-shaped cross-section, although any other suitable cross-section may be used, such as square as seen in Figure 4.

A transverse member formed as a rib 4 is provided on each side of the vertical support elements 3a, 3b and extends laterally inwardly from the base of each half-cell la, lb such that a plurality of ribs 4 are spaced along the longitudinal length of each half-cell la, lb. The ribs 4 are formed as planar elements and are orientated in vertical planes orthogonal to the longitudinal length of each half-cell la, lb. The edge of each rib 4 distal the base has a semi-circular edge 26a, 26b and when the two half-cells la, lb are joined together, the semi-circular edges of the ribs 4 of the top and bottom half-cells Ia, lb delimit a circular channel through the cell 1. It is envisaged that the ribs may be formed not as planar ribs, but in any other suitable form to deflect sediment, silt, debris or the like carried in a fluid flowing through the channel. Other shapes of rib are envisaged to form, for example, a square, oval or flat-bottomed channel. The channel may have a different shape in either half-cell.

Webs 5 are provided between adjacent ribs 4 on each half-cell la, lb. A plurality of spaced webs 5 are provided. The webs 5 extend from the base of each half-cell la, lb respectively. The webs 5 are planar and are orientated is vertical planes parallel to the longitudinal direction of the cell 1 and channel 25 formed therein. Each web 5 extends from the base 2a 2b of each half-cell 1 a, I b to a level in line with the semi-circular edge 26a, 26b of the ribs 5 and thereby also delimit the edge of the channel 25. The webs 5 and ribs 4 provide rigidity to the cell 1. In use, the cell 1 is located underground and the vertical support elements 3a, 3b, ribs 4 and webs 5 serve to resist load applied to the cell I and maintain the structural integrity of the cell 1 and channel 25.

In the lower half-cell la, the ribs 4, which are orthogonal to the webs 5 form fluid connection in the form of rectangular ducts 7a, 7b which fluidly connect the channel 25 through the base of the cell 1 in the bottom half cell 1 a. Similarly, the ribs and webs of the upper half-cell lb fluidly connect the channel 25 through the top of the cell 1, i.e. the base of the upper half-cell lb. It is also envisaged that other ducts or fluid connections may be provided for fluidly connecting the channel through the base or bottom and/or top of the cell.

In order to join the two half-cells la, lb together, a connecting member 6 is provided along the top longitudinal edge of the half-cells la, lb. The connecting member comprises a planar strip with male connecting pieces 13 on each side. The male connecting pieces 13 corresponding with and locate in the female D-shape holes in the vertical support elements 3a, 3b. Other connecting means are also envisages, for example adhesive. Instead of 0-shaped holes, the corresponding connecting pieces may have any other suitable form, for example circular or square for example.

As may be seen in the side view of the cell in Figure 1, the outermost webs 14a, 14b extend partially from the base 2a, 2b to the top of each half-cell la, lb. In this way, the webs serve to restrict the opening between the vertical support elements 3a, 3b at the baseofthecelll.

The assembled cell 1 is shown in Figure 3. In use, water flows into the channel 25. The webs 5 serve to prevent all the fluid flowing immediately out of the cell. The ribs 4, which are positioned transverse to the normal flow of fluid through the channel 25, serve as flow retardant means and seek to encourage and deflect particulates, such as silt and debris, dispersed in the fluid to sediment and pass out of the cell through the ducts 7a. The cell I may form a module of a drainage system. In this way, debris and silt is removed from the fluid flowing into the cell 1, before it passes into adjoining water attenuation cells (not shown). This seeks to prevent silt being deposited in the adjoining attenuation cells and therefore prevents the volumetric capacity of the attenuation cells being reduced. The gaps between the vertical support elements 3a, 3b allow fluid to pass into adjoining attenuation cells. If the flow of water into the cell 1 is greater than the capacity of the channel 25, water may also pass out of the ducts 7b in the top half-cell into adjoining attenuation cells of the system.

The channel 25 of the cell 1 also allows an inspection device such as a remote robot camera to be passed down the channel 25 to inspect the drainage system.

Figure 4 shows a further embodiment of the present invention. The cell 101 is formed similarly to the cell 1 of Figure 1. In addition, between adjacent support elements 103, there is provided a boundary web 108. The boundary web 108 is formed as a lattice ill such that fluid may flow between adjacent support elements 103.

The channel 125 is also provided with a channel wall 109, which extends in the longitudinal direction of the channel 125. The channel wall is provided with rectangular slits 110 over its full surface. The slits 110 provide a fluid connection from the channel to the ducts 107 formed by the ribs and webs. Other forms of holes, are envisaged in the channel to provide a fluid connection to the ducts. The channel may also be formed as a mesh.

As shown in Figures 5 and 6, the channel wall is formed separately from the cell 101.

The channel wall is formed as two corresponding half walls 109a, 109b, each with a semi-circular cross section. The semi-circular half walls 109a, 109b are formed with a flange 112a, 112b on each end. The flanges 112a, 112b form a connecting member, which is provided with male connecting members 113a, 113b to engage with corresponding female holes 117 in the support elements of each of the half-cells lOla, bib.

Figure 7 shows a further embodiment of a cell according to the present invention.

Instead of the D and square shaped support elements of the embodiments of Figures 1 and 4, the cell 201 comprises a plurality of hollow cylindrical support elements 203 spaced along the longitudinal boundary walls and also along the outermost webs 214a, 214b. On the boundary walls of the cell 201, spacer elements 217 are provided between adjacent support elements 203. Between the support elements 103 and between adjacent spacer elements 217, a lattice structure 211 is provided, to allow fluid to flow between the support elements 203 of the boundary wall of the cell 201. The volume formed between the outermost webs 214a, 214b and the lattice structure 211, provides a fluid attenuation volume. Instead or the lattice structure, any other water permeable structure is envisaged.

As shown in Figure 8, the cell 201 is formed as two half-cells 201a, 201b. As with the embodiments of Figures 1 and 3, transverse members in the form of ribs 204 are provided orthogonal to the longitudinal direction of the channel 225 and webs 205 are provided parallel to the longitudinal direction of the channel to form ducts 207 fluidly connected with the channel and the base of each half-cell 201a, 201b. In the embodiment of Figure 7, the outermost lateral webs 214a, 214b extend to the top of each respective half-cell 201a, 201b. This increases the restriction to lateral flow of fluid from the channel 225.

The channel 225 is provided with spaced lateral passages 215 at the top of each half-cell 201a, 201b. These lateral passages 215 allow fluid to flow from the channel 225 if the flow of fluid into the cell 201 exceeds its capacity.

As shown in Figure 8, the two half-cells 201a, 201b are joined together with a planar connecting member 206 which is formed to receive the tops of the support elements 203 of each half-cell 201a, 201b. A semi-circular channel wall 209 is formed integrally with each half cell 201a, 201 such that when the two half-cells are joined together, a channel 225 with a circular cross-section is formed.

As shown in Figures 8 and 9, an auxiliary channel 216 is provided under the base of the bottom half-cell 201a. The auxiliary channel 216 is fluidly connected to the through channel 225 via the ducts 207. The auxiliary channel 216 serves to collect silt. The flow of water through the ducts 207 into the auxiliary channel 216 carries silt out of the system to be captured by a chamber (not shown) downstream of the cell 201. The auxiliary channel 216 therefore self cleans. In addition, if needed, the silt collected may be jetted out of the auxiliary chamber 216 using a high pressure water jet, should the auxiliary chamber 216 become blocked. Further, for maintenance, water may be introduced into the auxiliary channel 216. In this way, water will then flow through the ducts and other flow paths in the system therefore serving to flush the system.

The channel wall 209 is formed integrally with and joins the ribs of each half-cell 201a, 201 b, although it will be understood that a separate channel wall may be used as in the embodiment of Figure 3.

The auxiliary channel 216 is preferably formed as a substantially U-shaped channel.

The channel may be formed with other suitable cross sections, such as square bottomed, V-shaped or semi-circular for example. The auxiliary channel 216 is connected to the cell base of the lower half cell 201a. The auxiliary channel 216 comprises a plurality of reinforcing ribs.

In the embodiment shown, the auxiliary channel 216 is open along its full length, the open channel being connected to the bottom or base of the drainage cell 201. The auxiliary channel could be closed partially along its length. The auxiliary channel could be formed integrally with the drainage cell. The auxiliary channel may be formed separately and joined to form part of the cell. In addition, an auxiliary channel may be provided within the boundary of the cell.

A drainage cell, without the through channel, may also be provided with a channel adjoining a boundary thereof. The channel may be formed according to any of the features of the auxiliary channel described.

Figure 10 shows a cross section in a vertical plane along the central axis of the cell 201 and shown the flow paths of the fluid in the cell 201. The normal flow of water into the cell 201 is in the longitudinal direction of the channel as shown by he arrow 218. The ribs, which are transverse to the normal direction of fluid flow in the channel of the cell, serve to encourage particulate material dispersed in the water to sediment. The sediment is carried by fluid though the ducts 207a into the auxiliary channel. 216. The lateral passages 215 are positioned spaced from the bottom of the channel to temporality keep fresh water, i.e. water that has come into the cell, in the channel. This serves to encourage the particles to be removed from the channel. If the flow into the cell should exceed the capacity along the channel and also the flow 219 through the lateral passages 215, the fluid may flow vertically up as shown by the arrow 220 though through the ducts 207b in the upper half-cell 201 b into adjacent flow attenuation cells (not shown).

Figure 11 shows detail of the lateral passage 215 in the outermost webs of the cell 201 The lateral passages 215 permit water to flow out of the channel 225. The lateral passages 215 are located at the joining portion of each half-cell 201a, 201b. Figure 12 shows a cross section along a plane parallel to the webs 214a. It can be seen that the lateral passages extend from the channel 225 to the attenuation volumes provided at either side of the cell 201.

Figures 13 and 14 show a further embodiment of the present invention. The cell 301 comprises two half-cells 301a, 301b. This embodiment is similar to the embodiment of Figure 7, but the channel wall 309 is formed separately from the cell 301 and formed with the connecting member 306. The channel wall 309 is located spaced from the edges 326 of the ribs 304 concentrically within the channel 325 delimited by the ribs 304. As shown in Figure 14, the channel wall has holes in the form of spaced slits 310 to correspond with the ducts 307 and also holes 328 to correspond with the lateral passages 315 formed in the outermost duct-forming webs 314 of the cell 301.

Figure 15 shows a cell 401 of an embodiment of the present invention in a ground water handling system. The drainage cell may be formed as a cell of any of the embodiments described. The system comprises a plurality of modular attention cells which form an attenuation volume 423. The drainage cell 401 forms a foundation module of the system. Water flows from a catch pit 424, for example, and flows via a pipe 422 into the channel 425 of the drainage cell 401. Overflow water flows into the attenuation volume 423. Silt and debris are collected in the auxiliary channel 416 located under the drainage cell 401.

Access to the channel 425 may be gained via the pipe 422, in order that maintenance of the system may be carried out. In addition inspection of the drainage cell 410 and attenuation volume 423 made be carried out using a remote camera, for example, which travels along the channel. Alternatively, the drainage cell 401 may be located higher up in the system, depending on where the pipe 422 is connected to the attenuation volume 423, or where inspection or maintenance is required.

In the embodiment shown, the drainage cell 401 with the channel 425 comprises one cell of the system, with the other attenuation cells being provided without a channel 425. Alternatively, all the cells of the system may of the type with a channel. In this way, the system may be inspected at various locations.

The connecting member for connecting the two half-cells of the drainage cell together may be selected with a predetermined thickness to produce an assembled drainage cell of sufficient dimensions, e.g. height, to match those of adjoining attenuation cells.

This enables the drainage cell to be used in a system comprising attenuation cells of different sizes. The connecting member may also be provided with connecting members which interlocks both with the drainage cell and adjacent attenuation cells.

A porous or non-porous geotechnical material may be used to cover the outer boundary of the drainage cell and/or the total attenuation volume.

The gec-membrane may be bonded, e.g. welded to the auxiliary channel 416 to form a seal between the cell and the auxiliary channel.

The ground water handling system may be flushed by the introduction of water into the structure at certain points in the system, with the outlet to the outlet pipe 422 blocked off.

When an auxiliary channel 416 is not used, water entering the drainage cell via the channel 425, will serve to self clean the channel of built-up silt.

In order to connect individual attenuation cells together, lateral connecting means such as lateral fastening clips may be used which attach between adjacent cells. Further, shear connecting means may be provided which may be inserted in corresponding holes provided in the top and bottom of vertically stacked drainage cells. The open ends of the support elements may provide suitable holes. The holes and connectors may be of any suitable cross section, e.g. circular. The connectors provide resistance to shearing between vertically stacked cells.

When a cell is not connected to a pipe at either the inlet or outlet to the channel, closure means may be provided to close the respective channel opening. Support means may also then be provided, either integrally with the closure means or forming part of the cell, by which geo-membrane material may be supported across the opening.

Claims

CLAIMS1. A drainage cell for a ground water handling system, the cell comprising a through channel, the cell comprising one or more transverse members extending from or adjacent the edge of the through channel towards a base of the cell for deflecting, in use, particulates or debris carried in a fluid flowing in said through channel.
2. A drainage cell according to claim 1, wherein the transverse members extend from substantially the edge of the through channel towards one or more lateral sides of the cell.
3. A drainage cell according to claim 1 or 2, wherein the transverse members extend across the width of the cell, except across the through channel.
4. A drainage cell according to any one of claims 1 to 3, wherein the transverse members are orientated substantially orthogonal to the longitudinal direction of the through channel.
5. A drainage cell according to any one of the preceding claims, wherein the transverse members are planar.
6. A drainage cell according to any one of the preceding claims, wherein the transverse members are orientated in substantially vertical planes substantially orthogonal to the longitudinal direction of the through channel.
7. A drainage cell according to any one of the preceding claims, wherein the edges of the transverse members delimit the through channel.
8. A drainage cell according to any one of claims 1 to 6, wherein the through channel comprises a perforated channel wall.
9. A drainage cell according to claim 8, wherein the channel wall delimits the through channel.
10. A drainage cell according to any one of the preceding claims, wherein one or more fluid connections are provided from a side of said channel.
11. A drainage cell according to claim 10, wherein the cell further includes an auxiliary channel fluidly connected to said through channel via said fluid connections.
12. A drainage cell according to claim 11, wherein the auxiliary channel adjoins the base of said cell.
13. A drainage cell according to claim 11 or 12, wherein the auxiliary channel has a U-shaped cross-section.
14. A drainage cell according to any one of claims 11 to 13, wherein the auxiliary channel comprising reinforcing ribs.
15. A drainage cell according to any one of the preceding claims, wherein the cell comprises webs which adjoin adjacent transverse members.
16. A drainage cell according to claim 15, wherein the webs extend from substantially the edge of the channel towards the base of the cell.
17. A drainage cell according to claim 15 or 16, wherein the webs extend across the cell, except across the through channel.
18. A drainage cell according to any one of claims 15 to 17, wherein the webs are planar.
19. A drainage cell according to claim 15 to 18, wherein the webs are orientated in substantially vertical planes, parallel to the longitudinal direction of the through channel.
20. A drainage cell according to any one of claims 15 to 19, wherein the webs are arranged to restrict, in use, the flow of water orthogonal to the longitudinal direction of the through channel.
21. A drainage cell according to any one of the preceding claims, when dependent on claim 10, wherein the one or more fluid connections extend from the channel through an external boundary of the cell.
22. A drainage cell according to any one of the preceding claims, when dependent on claim 10 and claim 15, wherein the transverse members and said webs form said fluid connections.
23. A drainage cell according to any one of the preceding claims, when dependent on claim 10, wherein the fluid connections extend through the base of the cell.
24. A drainage cell according to any one of the preceding claims, when dependent on claim 10, wherein the fluid connections extend through the top of the cell.
25. A drainage cell according to any one of the preceding claims, wherein one or more lateral fluid passages are formed in the side of said through channel.
26, A drainage cell according to claim 25, wherein the opening of each lateral passage in the side of the channel is spaced above the base of the channel.
27. A drainage cell according to claim 25 or 26, wherein the cell comprises an attenuation volume adjacent said through channel, the attenuation volume being fluidly connected to said through channel via said one or more lateral passages.
28. A drainage cell according to any one of the preceding claims, wherein the through channel is formed with a circular cross-section.
29. A drainage cell according to any one of the preceding claims, wherein the cell comprises vertical support elements.
30. A drainage element according to any one of the preceding claims, wherein the cell is provided with one or more perforated boundary walls.
31. A drainage cel' according to any one of the preceding claims, when dependent on claim 8, wherein the channel wall is formed integrally with the cell.
32. A drainage cell according to any one of claims 1 to 30, when dependent on claim 8, wherein the channel wall is formed as a separate part.
33. A drainage cell according to any one of the preceding claims, when dependent on claim 8, wherein the channel wall is spaced from the transverse members.
34. A drainage cell according to any one of the preceding claims, wherein the cell is formed of two half cells.
35. A drainage cell according to claim 34, wherein a connecting member is provided for connecting the two half-cells together, which connecting member has connecting means which connect with corresponding parts of each half cell.
36. A drainage cell according to claim 35, wherein the drainage cell is configured to receive connecting members of various thicknesses to form a drainage cell of predetermined exterior dimensions.
37. A drainage cell according to any one of the preceding claims, wherein the cell forms a module of a drainage assembly.
38. A drainage assembly, wherein the drainage assembly comprises a plurality of water attenuation cells including one or more drainage cells according to any one of claims 1 to 37.
39. A drainage assembly according to claim 38, wherein the cells are provided with lateral or shear connecting means to connect adjacent and/or vertically stacked cells together.
40. A drainage cell comprising an attenuation volume, the cell comprising a channel adjoining a boundary of said cell and being fluidly connected to said attenuation volume.
41. A drainage cell according to claim 40, wherein the channel is formed separately from and joined to form part of said cell.
42. A drainage cell substantially as described herein with reference to and as illustrated in the accompanying figures.