GB2460709A

GB2460709A - A shroud for deflecting wet concrete into an annular space around a manhole

Info

Publication number: GB2460709A
Application number: GB0817858A
Authority: GB
Inventors: Wayne Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-06-06
Filing date: 2008-10-01
Publication date: 2009-12-09
Also published as: GB0817858D0; GB0810348D0

Abstract

The invention relates to a manhole shroud for deflecting cementitious material around a manhole duct. The shroud comprises side walls 11 which converge from a base region 12 to an apex 13 disposed substantially above a centre of the base region. The shroud may be hemispherical, pyramidal or conical in shape, with a smooth surface and manufactured from fibre glass. The surface of the shroud may have a plurality of grooves which extend directly down from the apex 13 to the rim 14 as an aid to encourage the flow of concrete. The shroud may also have a lifting eye 15.

Description

Manhole Shroud The present invention relates to a manhole shroud and particularly, but not exclusively, to a manhole shroud for deflecting concrete around the manhole.

New building developments require an underground network of ducts to remove waste water and effluent. These ducts are serviced through so-called "manholes" which comprise a riser duct that extends from an underground duct, to the surface. These riser ducts are typically preformed concrete sections and are suitably connected to the appropriate underground duct that has been exposed by excavating the surrounding ground. The riser ducts comprise an opening or manhole at the top, namely ground level, through which service personnel can pass to access the underground network of ducts.

Once positioned, the riser duct is typically reinforced by surrounding the duct with a collar of concrete and once the concrete has set, the excavated soil/earth is returned around the riser duct to cover the riser duct, so that only the top surface of the manhole is left exposed. In order to reinforce the riser duct with concrete however, a shutter is first positioned around the periphery of the duct along the length of the duct, but spaced from the outer surface of the duct. The spacing between the outer surface of the duct and the inner surface of the shutter defines the thickness of the concrete collar. A board or similar is then placed over the opening to the manhole and concrete is poured upon the board.

The board serves to prevent any concrete from falling into the manhole.

The concrete is subsequently pushed off the board using a shovel, for example, so that it falls between the outer surface of the duct and the inner surface of the shutter. Accordingly, while one person pours the concrete upon the duct, a second person is required to distribute the concrete evenly around the duct.

It is to be appreciated therefore that this is a time consuming process, as the concrete must be poured in stages to enable a person to suitably distribute the concrete around the duct. Moreover, in order to reinforce a riser duct at least two persons are required -one for pouring the concrete and one for distributing the concrete.

I have now devised a shroud which alleviates the above mentioned problems.

In accordance with the present invention, as seen from a first aspect there is provided a manhole shroud, the shroud comprising side walls which converge from a base region to an apex disposed substantially above a centre of the base region.

By positioning the shroud over the manhole, then concrete poured upon the apex can fall down the side walls to surround the riser duct. This obviates the need to manually distribute the concrete around the riser duct. Moreover, by positioning the apex above the centre of the base, then concrete poured upon the apex becomes evenly distributed around the riser duct.

Preferably, the shroud is substantially hemispherical, pyramidal or conical in shape.

Preferably, the manhole is used to deflect cementitious material, such as concrete, that is poured upon the shroud, around the manhole. The wall of the shroud is preferably smooth to allow the concrete to slide off the wall.

Preferably, the wall of the shroud comprises at least one groove that extends down from the apex of the shroud to the base region, to direct the passage cementitious material off the shroud.

Preferably, the shroud further comprises an eyelet disposed at the apex so that the shroud can be lifted using machinery, such as a crane and thus be suitably positioned upon a manhole.

Preferably, the shroud is formed of fibre glass.

According to a second aspect of the present invention there is provided the use of the shroud of the first aspect for deflecting cementitious material around a manhole duct.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a first embodiment of the shroud of the present invention; Figure 2 is a perspective view of a second embodiment of the shroud of the present invention; Figure 3 is a perspective view of a third embodiment of the shroud of the present invention; and, Figure 4 is an exploded view of the shroud of figure 1 and manhole.

Referring to figures 1 to 3 of the drawings, there is shown a manhole shroud 10 according to the present invention. The shroud 10 comprises side walls 11 which extend from a base region 12 to an apex 13 disposed substantially above the centre of the base region and may be formed of fibre glass, for example.

The base region 12 comprises a rim 14 and the side walls 11 extend from the rim 14 to the apex 13 so as to form a hemispherical (figure 1), pyramidal (figure 2), conical (figure 3) or similar shape such that concrete or other material, for example soil or gravel can slide off the side walls and develop around the base region 12. The shroud illustrated in the drawings is an open structure to reduce the weight of the shroud, however the base region 12 may comprise a base plate (not shown) secured to the rim 14, to close the interior of the shroud 10 and thus further act to strengthen the shroud 10. In this case, it is preferred that the side walls 11 and base plate (not shown) are formed as one-piece.

The shroud 10 further comprises an eyelet 15 or similar that extends from the apex 13 to enable the shroud 10 to be readily secured to lifting equipment (not shown) so that the shroud can be lifted into position.

Referring to figure 4, in use the shroud 10 is positioned atop a riser duct 16 sO as to cover the manhole 17 to the riser duct 16. A shutter 18 (shown dashed in figure 4) is placed around the manhole and concrete is poured upon the apex 13 of the shroud 10. As the concrete falls upon the apex 13, it slides down the side walls 11 and falls into the cavity 19 between the outer surface of the riser duct 16 and the inner surface of the shutter 18. Once the cavity 19 has been filled level with the upper surface of the riser duct 16 the pouring of concrete is stopped and the shroud 10 can be removed from the top of the riser duct 10.

This can be achieved simply by lifting the shroud 10 manually or by securing a rope or similar between the eyelet 15 and lifting equipment (not shown).

To encourage the flow of concrete into the cavity 19, the surface of the side walls 11 may comprise a plurality of grooves (not shown) which may extend directly down from the apex 13 to the rim 14, or which may spiral down around the shroud 10 from the apex 13 to the rim 14.

From the foregoing therefore it is evident that the shroud of the present invention provides for a simple yet effective means of distributing concrete around a manhole.

Claims

I-Claims 1. A manhole shroud, the shroud comprising side walls which converge from a base region to an apex disposed substantially above a centre of the base region.
2. A shroud according to claim 1, wherein the shroud is substantially hemispherical, pyramidal or conical in shape.
3. A shroud according to claim 1 or 2, wherein the shroud is used to deflect cementitious material that is poured upon the shroud, around the manhole.
4. A shroud according to any preceding claim, wherein the wall of the shroud is smooth.
5. A shroud according to any of claim 1 to 3, wherein the wall of the shroud comprises at least one groove that extends down from the apex of the shroud to the base region.
6. A shroud according to any preceding claim, wherein the shroud further comprises an eyelet disposed at the apex * ** * * a
7. A shroud according to any preceding claim, wherein the shroud is formed **** of fibre glass. **a* * I I...
8. Use of the shroud of the first aspect for deflecting cementitious material around a manhole duct.* .. I.* * 30
9. A shroud substantially as herein described with reference to the accompanying drawings.