GB2297780A - Manhole and drainage gullies - Google Patents

Abstract

A manhole has a main body defining a lowermost chamber with inlet and outlet pipes, an intermediate passage immediately above and of smaller diameter than the chamber, and an uppermost passage of smaller diameter than the intermediate passage. In addition to a manhole cover, a grating 26 provides a wastage trap in the intermediate passage. The grating 26 is supported on an annular flange 28 and is formed in two halves which are releasably locked together by a locking device 38. The position of the grating 26 is such as to normally obviate or mitigate unauthorised tampering therewith, but is positioned in fresh air and accessible to authorised personnel for maintenance. The grating 26 prevents raw materials and heavy objects reaching the lowermost chamber of the manhole. To allow authorised personnel further into the manhole, the device 38 can be unlocked and the separated halves of the grating 26 removed from the uppermost passage or moved to a non-obstructing location in the latter. A vertical perforated pipe may pass through the grating to allow water to pass down the manhole if the grating becomes blocked.

Description

Improved Hanholes and Drainage Gullies This invention is concerned with arresting movement of solids in passages, and is particularly concerned with traps for arresting passage of waste material into sewerage manholes and storm water drainage gullies.

It is not uncommon for solids in the form of raw materials and heavy objects to enter or be introduced to sewerage manholes and storm water drainage gullies, resulting in clogging of the drainage system.

Intentional abuse in a similar way of public utilities such as manholes is also not uncommon in some countries.

According to the present invention there is provided trap apparatus for arresting movement of solids in a passage, the apparatus comprising apertured means having a configuration substantially complementary to the cross-section of the passage, and being adapted to be supported on positioning means at a predetermined location in the passage, the apertures being arranged to substantially prevent movement of solids through the trap apparatus further into the passage.

Preferably the apertured means has the form of a grating. The latter is preferably formed of a material which is resistant to corrosion and rust, for example a moulded glass reinforced plastics material (GRP).

The grating may be adapted to be fixedly secured on the positioning means.

In one embodiment, the grating is formed of two sections which are releasably stacked or locked together, whereby to enable the sections, when released, to be movable through another passage of smaller cross-section, or to be suspended in the passage.

In another embodiment, a tubular member is mounted on the grating to extend from one side thereof and to open on to the other side thereof, the wall of the tubular member being perforated.

The present invention also provides a drainage gully comprising a main body defining a passage having an open end, cover means for the open end providing an inlet for drainage into the main body, a drainage outlet in the main body, and trap apparatus as described in any of the five preceding paragraphs supported on the main body in a spaced relation to the cover means to arrest movement of solids introduced through the open end of the main body.

Preferably the positioning means comprises an inwardly extending flange mounted on an inner peripheral wall of the main body.

The invention further provides a manhole comprising a main body defining a passage having an open end, cover means for the open end, and a trap apparatus, as described in any of the five paragraphs preceding the last two paragraphs, supported in the main body in a spaced relation to the cover means to arrest movement of solids introduced through the open end of the main body.

The positioning means may comprise an inwardly extending flange mounted on an inner peripheral wall of the main body.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a top plan view of a first embodiment of a trap for a manhole; Fig. 2 is a sectional side elevation of part of a manhole utilising the trap of Fig. 1; Fig. 3 is a diagrammatic side elevation on reduced scale of a manhole utilising a trap according to Figs. 1 and 2; Fig. 4 is a sectional side elevation of a horizontal drainage gully utilising a second embodiment of trap according to the invention; Fig. 5 is a sectional end elevation of the gully of Fig. 4; Fig. 6 is a plan view of the trap used in the gully of Figs. 4 and 5; Fig. 7 is a further embodiment of a trap according to the invention for use in a horizontal drainage gully; and Fig. 8 is a sectional end elevation through a vertical gully incorporating a trap according to the invention.

Referring to Fig. 3 of the drawings, a manhole 10, for use in providing access to a public utility such as a sewer system, has a constructed main body 12 of substantially circular cross-section having a closed lower end defining a lowermost chamber 14 with inlet and outlet pipes 16, 18 respectively, an intermediate passage 20 immediately above the chamber 14 and of smaller diameter than the latter, and an uppermost passage 22 of smaller diameter than the passage 20. The passage 22 has an open upper end closable by a manhole cover 24.

At a location in the intermediate passage 20 there is supported a wastage trap in the form of a grating 26 which has a configuration substantially complementary to the cross-section of the passage 20. As shown in Fig. 2, the trap 26 is supported on an inwardly extending annular flange 28 which forms the leg of a T-shape, with the head of the T being secured to the wall of the passage 20 by means of respective anchoring bolts 30, 32 through mounting sections 33a, 33b respectively above and below the flange 28. A plurality of each of the bolts 30, 32 are used at spaced locations around the mounting sections 33a, 33b.

As shown in Fig. 1, the trap 26 is in the form of a grating defined by a plurality of bearing bars 34 and a plurality of bridging bars 36 at right angles thereto.

The trap 26 is formed in two halves which are releasably locked together at a central location on their adjacent edges by a suitable locking device 38.

The trap 26 is spaced far enough below the manhole cover 24 to normally obviate or mitigate unauthorised tampering with the trap, but is still positioned in fresh air and accessible to authorised personnel for maintenance. More than one of the traps 26 may be used in a manhole depending on the depth of the manhole, and preferably the traps 26 would be positioned at 4 metre intervals. The design of the grating enables passage of air therethrough for ventilation of the manhole. The grating is formed of a material which is resistant to corrosion and rust, preferably GRP, which also reduces the dead weight of the grating. The grating 26 is structurally efficient and stable to withstand a predetermined load, for example, of 200 kg, or a free falling impact load.

The grating 26 prevents solids in the form of raw materials and heavy objects from entering the sewage system and clogging same, and therefore guards the system against any intentional or unintentional abuse.

The location of the grating in the intermediate passage 20 of the manhole prevents removal of the grating more than an arm's length from the upper end of the passage, because of the reduced diameter of the uppermost passage 22. For access further into the manhole, authorised personnel can unlock the device 38 and remove each half of the grating 26 through the uppermost passage 22, or hang each on a hook (not shown) provided in the passage 20.

In a further embodiment as shown in Figs. 4 to 6, a horizontal storm water gully unit 40 has a main body 42 of reinforced concrete defining a chamber 44 of substantially square cross-section which is closed at its lower end and has an open upper end. The latter is covered by a grate 46 which, in use, is at road level immediately adjacent a roadside kerb assembly 48, whereby surface water can drain through the grate 46 into the chamber 44. An outlet 48 for the chamber 44 is formed in a wall of the body 42.

Spaced below the grate 46, a wastage trap 50 is supported in the chamber 44 by means of an inwardly extending peripheral flange 52 which has a mounting leg 54 at right angles thereto secured by anchoring bolts 56 to the wall of the body 42. The trap 50 is fixedly secured to the flange 52 by a plurality of bolts (not shown) extending through respective parts of the trap 50, through the flange 52 into threaded nuts (not shown) welded onto the lower face of the flange 52. The trap 50 is positioned between the grate 46 and the outlet 48 and has a configuration substantially complementary to the cross-section of the chamber 44.

As shown in Fig. 6, the trap 50 is formed with a plurality of bearing bars 52 and a plurality of bridging bars 54, and is formed of a material which is resistant to corrosion and rust, for example GRP. At a central location on the trap 50 is fastened a tubular open-ended pipe 56 which extends forwardly of one side of the trap 50, the upper side in use, and opens on to the other side of the trap 50. The pipe 56 is perforated throughout its length.

In a similar way to the first embodiment, the trap 50 prevents abuse of the gully due to solids being introduced to the chamber 44 and clogging the system.

If the trap 50 becomes itself clogged by solids, whereby to substantially prevent liquid flow therethrough, the perforated pipe 56 then acts as a drain to maintain the drainage facility. The lower part of the chamber 44 may also be cleaned by the use of a vacuum hose passed through the pipe 56. For access to the lower part of the chamber 44, the trap 50 is positioned to be accessible to authorised personnel for release of the securing bolts. The trap can then either be removed through the open upper end of the body 42 or can be lifted off the flange 52 and lowered against the side of the chamber 44, being held by a retaining line 58 which is secured at one end to the body 42 and at its other end has a loop 60 located around part of the trap 50.

In a further embodiment as shown in Fig. 7, a wastage trap 62 of a rectangular configuration is adapted for use in a horizontal gully which has two inlets (not shown). Like references are used to denote like components to those of the wastage trap 50.

Referring to Fig. 8, a vertical gully 64 has a main body 66 of reinforced concrete defining a chamber 68 with a closed lower end and open upper end, with an outlet 70 in a wall of the body 66 communicating with the chamber 68. The body 66 may be of any suitable cross-section, for example of 0-shape, whereby to present a planar side face 72 to locate along the edge of a roadway for the purpose hereinafter described.

A top unit 74, of a similar cross-section to the body 66, is supported on the upper end of the latter and presents a chamber 76 into which road surface water can drain through a horizontal inlet 78 which slopes downwardly from an outer edge of the top unit 74 at the roadside level to the chamber 76. From the latter, the drainage water passes into the chamber 68 to the outlet 70. The top unit 74 has an upper end opening normally closed by an access cover 80.

Within the body 66 there is supported a wastage trap 82 which has a configuration complementary to the cross-section of the chamber 68 and is mounted on an inwardly extending flange 84. The latter has a mounting part 86 at right angles thereto secured to the body 66 by anchor bolts 88 in a manner similar to that described in relation to the embodiment of Figs. 4 to 6. The trap 82 has a construction similar to that of the embodiment of Figs. 4 to 6 and is similarly provided with a perforated pipe 90 for the same purposes as before described.

There is thus provided a wastage trap which is economical and easy to use and which guards the respective system against intentional and/or unintentional abuse by the introduction of solids which can clog the system and cause damage. The trap is adapted to be supported at the optimum position to obviate or mitigate tampering by unauthorised personnel but be accessible to authorised personnel.

Various modifications may be made without departing from the invention. For example the wastage trap may be of a suitable construction other than those described and shown.

Whilst endeavouring in the foregoing Specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims (15)

Claims:

1. Trap apparatus for arresting movement of solids in a passage, the apparatus comprising apertured means having a configuration substantially complementary to the cross-section of the passage, and being adapted to be supported on positioning means at a predetermined location in the passage, the apertures being arranged to substantially prevent movement of solids through the trap apparatus further into the passage.

2. Apparatus according to Claim 1, wherein the apertured means has the form of a grating.

3. Apparatus according to Claim 2, wherein the grating is formed of a material which is resistant to corrosion and rust.

4. Apparatus according to Claim 3, wherein the material is a moulded glass reinforced plastic.

5. Apparatus according to any of Claims 2 to 4, wherein the grating is adapted to be fixedly secured on the positioning means.

6. Apparatus according to any of Claims 2 to 5, wherein the grating is formed of two sections which are releasably stacked or locked together, whereby to enable the sections, when released, to be movable through another passage of smaller cross-section, or to be suspended in the passage.

7. Apparatus according to any of Claims 2 to 5, wherein a tubular member is mounted on the grating to extend from one side thereof and to open on to the other side thereof, the wall of the tubular member being perforated.

8. A drainage gully comprising a main body defining a passage having an open end, cover means for the open end providing an inlet for drainage into the main body, a drainage outlet in the main body, and trap apparatus according to any of the preceding Claims supported on the main body in a spaced relation to the cover means to arrest movement of solids introduced through the open end of the main body.

9. A gully according to Claim 8, wherein the positioning means comprises an inwardly extending flange mounted on an inner peripheral wall of the main body.

10. A manhole comprising a main body defining a passage having an open end, cover means for the open end, and a trap apparatus according to any of Claims 1 to 7 supported in the main body in a spaced relation to the cover means to arrest movement of solids introduced through the open end of the main body.

11. A manhole according to Claim 10, wherein the positioning means comprises an inwardly extending flange mounted on an inner peripheral wall of the main body.

12. Trap apparatus substantially as hereinbefore described with reference to the accompanying drawings.

13. A drainage gully substantially as hereinbefore described with reference to the accompanying drawings.

14. A manhole substantially as hereinbefore described with reference to the accompanying drawings.

15. Any novel subject matter or combination including novel subject matter disclosed, whether or not within the scope of or relating to the same invention as any of the preceding Claims.