GB2348441A

GB2348441A - Removable double weir silt trap for a drain

Info

Publication number: GB2348441A
Application number: GB0003298A
Authority: GB
Inventors: Jeremy David Keight
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-02-16
Filing date: 2000-02-15
Publication date: 2000-10-04
Also published as: GB0003298D0

Abstract

A device for trapping silt in a drain is removable and is preferably supported by a peripheral flange (13) which rests on a ledge (20) and is covered by a grille (22). The device may have two silt traps (12, 30) of weir formation. Water entering the device can exit an upper portion of the device via a stand-pipe arrangement (25) which is closed at its lower end (17) and leads into a lower portion of the device. The stand-pipe (25) preferably has a number of apertures (27) arranged around it's upper portion, via which, water can flow out of the lower portion of device and exit the drain. The device can be constructed form a one piece moulding of plastic.

Description

Title: Trap Device Description of Invention This invention relates to a trap device, for intercepting silt or other solid matter such as soil or gravel (which will all herein be referred to for convenience as silt) to prevent, as far as possible, such matter from entering a drain.

A drain for receiving storm water is nearly always provided with a covering grille or grating whose openings allow water to enter the drain while preventing the entry of large quantities of leaves or the like or any large object which might partially or completely block the drain. Such a grille does not, however, prevent silt from entering the drain, and it is possible for a build up of silt to occur at the bottom of the vertically-extending shaft part of the drain beneath the grille. Eventually such silt might block or unduly restrict the passage of water through the U-bend arrangement by which water usually flows to a drainage system from the drain in question. Therefore regular cleaning of the drain and removal of such silt is desirable, but this is an inconvenient and sometimes unpleasant operation.

It is broadly the object of the present invention to provide a trap device for intercepting and retaining silt entering a drain to facilitate removal and disposal thereof.

According to one aspect of the invention, we provide a trap device for disposition in a drain, comprising trap means for intercepting and retaining silt entering the drain and means providing for support of the device in the drain and removal therefrom for disposal of retained silt.

Usually the grille covering a drain is supporte on a peripheral ledge extending around the top of the vertical shaft of the drain. For engagement with such a peripheral ledge, the means for support of the device in the drain preferably comprises a formation or formations for engagement with such a ledge. The formation (s) may comprise a peripheral flange extending at least partially around the device, adapted to rest on the ledge with the grille on top of it.

For effective interception and retention of silt, the device preferably comprises two trap means arranged so that at least the majority of water entering the device passes successively through the two trap means.

Each of the two trap means preferably comprises a sedimentation chamber from which water having entered the chamber overflows by way of a weir formation.

Preferably the two trap means of the device are provided respectively in first and second body parts of the device, the second body part of the device being disposed beneath the first body part thereof.

The device conveniently comprises a first body part extending downwardly from the flange formation of the device and closed at its lower end by an upwardly extending stand-pipe arrangement whose upper end provides the aforesaid weir by which water can leave the first body pan.

The stand-pipe arrangement preferably leads downwardly into the second body part which is closed at its lower end and is provided at an upper part (adjacent the first body part) with aperture means by which water can flow out of the second body part and thus leave the device.

Preferably the aperture means for exit of water from the second body part comprises a plurality of apertures peripherally spaced thereabout.

For entry of water from the stand-pipe arrangement in the first body part into the second body part, preferably there are formations for directing such water between the exit apertures of the second body part so that further sedimentation of silt can occur in the second body part before the water leaves the latter.

A device in accordance with the invention may be made of plastics material and preferably is of a configuration such that it can be made as a onepiece moulding thereof. However, it will be appreciated that other materials may be utilise for the device.

The invention will now be described by way of example with reference to the accompanying drawings, of which : Figure 1 is a perspective view of a device in accordance with the invention; Figure 2 is a vertical section through the device, shown in situ in a drain; Figure 3 is a section as Figure 2, showing a build up of silt in the device in use; Figure 4 is an enlarged, broken away, view of part of the device.

Referring to the drawings, the trap device 10 in accordance with the invention comprises a first body part 11 which in use is an uppermost part of the device and a second, lower, body part 12. The first body part 11 is square in plan view having a peripheral flange 13 and comprises a wall which tapers pyramidally downwardly from the flange 13 as indicated at 14, the pyramidal shape of the wall 14 merging into a conically tapering wall part 15 at its lower end. At the bottom of the conical wall part 15 there is a more rapidly tapering inwardly extending portion 16 which leads to the second body portion 12. The second body portion 12 is cylindrical in configuration and is closed at its lower end as indicated at 17.

The peripheral flange 13 of the device provides for support of the device in a drain by resting on a peripheral ledge 20 which is characteristically to be found at the top of a vertical shaft 21 of a drain. The ledge 20 provides for support of a covering grille 22 which allows water to enter the drain whilst keeping out leaves and the like or large objects which might block the drain.

The thickness of the peripheral flange 13 of the device is such that it can rest on the ledge 20 with the grille 22 on top of it, the grille then only being slightly higher than it would otherwise have been if it had been resting directly on the ledge 20 without the device being present.

Near the bottom of the shaft 21 of the drain there is shown an exit pipe 23 leading to a drainage system: frequently a U-bend arrangement is provided in the pipe 23 so that some water is retained in the pipe 23 and bottom of the shaft 21 as a seal.

Drains commonly have covering grilles as 22 which are square in shape whilst the shaft beneath may be square or circular. The peripheral flange 13 of the device in accordance with the invention may be square in shape to suit such drains. However, it will be appreciated that the device could function equally well, as described hereafter, if it were circular or some other shape, e. g. rectangular at the top of its first body part and the peripheral flange 13.

The device in accordance with the invention preferably is a one-piece moulding of a plastics material, such a material being selected to have the required strength, rigidity and durability to enable the device to function satisfactorily and have a long life. However, it will be appreciated that other materials could possibly be used, to suit the environment in which the device is likely to be installed.

Within the first body part 11 of the device a cylindrical stand-pipe 25 extends upwardly from the region at which the conically tapering wall portion 15 joins the more shallowly inclined wall portion 16. The upper rim of the stand-pipe 25, as indicated at 26, lies slightly below the level of the peripheral flange 13. The wall portion 16 is provided with a plurality of circumferentially spaced apertures 27 each of which is covered by a respective arch formation 28 which extends radially inwardly from the bottom of the stand-pipe 25. The arches 26 end approximately level with the cylindrical wall of the lower body part 12. The effect is that the arches 28 shield the apertures 27 from water passing down the stand-pipe 25. These features are most clearly visible in Figure 4.

In use of the device in accordance with the invention, water entering the drain through the grille 22 will mostly pass into the tapering somewhat annular space forming a sedimentation chamber between the stand-pipe 25 and the wall portions 14,15 of the first body part 11. It will be appreciated that except at times of flood most water entering a drain does so by flowing down the sides of the vertical shaft thereof. Any silt carried by the water into the annular space (30) outside the stand-pipe 25 will tend to settle therein while the top rim 26 of the stand-pipe 25 acts as a weir from which water can overflow to run down the internal wall of the stand-pipe and between the arches 28 to enter the lower body portion 12 of the device. This lower body portion 12 is as above described closed at its lower end, and water will overflow through the apertures 27 at its upper end beneath the arches 28.

The device thus provides two trap arrangements in the form of sedimentation chambers respectively in the space 30 outside the stand-pipe 25 and in the lower body part 12. Any silt which does not settle out in the space 30 is provided with a second opportunity to settle out in the body part 12. The path in which water enters and flows through the device is shown by arrows in Figures 1,2 and 3, whilst build-up of silt in the space 30 and lower body part 12 is shown in Figure 3.

In use, it can be expected that the space 30 will fil ! with silt before the lower body part 12 is full up to the level of the apertures 27. When this condition has been reached, the device can simply be lifted from the drain and emptied at an appropriate disposal point. Assuming the condition of the device is checked regularly, it can be expected that such disposal of accumulated silt will take place before the lower body part of the device has been filled with silt, i. e. while the device still retains a capability to separate and retain silt.

It is to be appreciated that modifications to the invention may be made whilst retaining the principle of construction and operation above described.

In the present specification"comprise"means"includes or consists of' and"comprising"means"including or consisting of'.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for perfoiming the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS 1. A trap device for disposition in a drain, comprising trap means for intercepting and retaining silt entering the drain and means providing for support of the device in the drain and removal therefrom for disposal of retained silt.
2. A device according to Claim 1, wherein the means for support of the device in the drain comprises a formation or formations for engagement with a peripheral ledge.
3. A device according to Claim 2, wherein the formation (s) comprise a peripheral flange extending at least partially around the device, adapted to rest on the ledge with a grille on top of it.
4. A device according to any one of the preceding claims, wherein the device comprises two trap means arrange so that at least the majority of water entering the device passes successively tlwougli the two trap means.
5. A device according to Claim 4, wherein each of the two trap means comprises a sedimentation chamber from which water having entered the chamber overflows by way of a weir formation.
6. A device according to Claim 5, wherein the two trap means of the device are provided respectively in first and second body parts of the device, the second body part of the device being disposed beneath the first body part thereof.
7. A device according to Claim 5 or Claim 6, which comprises a first body part extending downwardly from the flange formation of the device and closed at its lower end by an upwardly extending stand-pipe arrangement whose upper end provides the aforesaid weir by which water can leave the first body part.
8. A device according to Claim 7, wherein the stand-pipe arrangement leads downwardly into the second body part which is closed at its lower end and is provided at an upper part (adjacent the first body part) with aperture means by which water can flow out of the second body part and thus leave the device.
9. A device according to Claim 8, wherein the aperture means for exit of water from the second body part comprises a plurality of apertures peripherally spaced thereabout.
10. A device according to Claim 9, wherein there are formations for directing water entering the second body part between the exit apertures of the second body part so that fuuther sedimentation of silt can occur in the second body part before the water leaves the latter.
11. A device according to any one of the preceding claims which is made of plastics material.
12. A device according to Claim 11 which is a one-piece moulding of said plastics material.
13. A trap device substantially as hereinbefore described with reference to the accompanying drawings.
14. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.