Background of the Invention Underground pipes, particularly those that carry sewerage often require inspection or maintenance. Access to the pipes is provided by a manhole base section that interconnects the underground pipes. The base section supports a riser that is covered by a manhole cover. This allows access to the base section for inspection or maintenance of the base section or the pipes.

Currently, manhole base sections are provided with a generally cylindrical wall surrounding a cavity into which the pipes connect. So as to enhance the flow of fluid or slurry from an inlet pipe to an outlet pipe a channel is fabricated into the base section.

The channel accommodates directional flow of fluid or slurry from the incoming to the outgoing pipe. This fabrication method is labour intensive and thus expensive.

Furthermore, it provides difficult working condition for the person fabricating the channel due to the cramped space.

An object of the present invention is to provide a new manhole base section that allows direct flow to the outlet, and easier access to the outlet for inspection and maintenance.

Summary of the Invention According to the present invention there is provided a manhole base section for connection of underground pipes, the base section including: a body, the body including a base, at least one side wall and a top; the top including an opening leading to a cavity extending into the body from the opening, the cavity having a bowl portion, the bowl portion having an inlet portion interfaced with an outlet portion, the inlet portion having a sloped wall so as to provide a sump, the sump joining the inlet portion to the outlet portion so that fluid collected in

the sump flows into the outlet portion; the outlet portion being funnel shaped and narrowing away from the interface with the inlet portion to an outlet for connection of an outlet pipe thereto, wherein the bowl portion is disposed relative to the side wall of the body so that the an inlet pipe may extend from the side wall into the inlet portion and an outlet pipe may extend from the side wall into the outlet, whereby, in use, a fluid or slurry enters the inlet portion via the inlet pipe, the fluid or slurry flows down the sloped wall of the inlet portion into the outlet portion, and out of the outlet portion via the outlet pipe.

According to another aspect of the present invention there is provided a manhole base section connected to underground pipes, the base section including: a body, the body including a base, at least one side wall and a top; the top including an opening leading to a cavity extending into the body from the opening, the cavity having a bowl portion extending into the body, the bowl portion having an inlet portion interfaced with an outlet portion, the inlet portion having a sloped wall so as to provide a sump, the sump joining the inlet portion to the outlet portion so that fluid collected in the sump flows into the outlet portion; the outlet portion being funnel shaped and narrowing away from the interface with the inlet portion to an outlet connected to an outlet pipe that extends to the side wall, wherein the bowl portion is disposed relative to the side wall of the body so that the an inlet pipe may extend from the side wall into the inlet portion, whereby, in use, a fluid or slurry enters the inlet portion via the inlet pipe, the fluid or slurry flows down the sloped wall of the inlet portion into the outlet portion, and out of the outlet portion via the outlet pipe.

Preferably, one or more further pipes may extend from the side wall into the inlet portion, whereby fluid or slurry from the further pipes may pass through the bowl portion to the outlet pipe.

Preferably, the body inside the cavity is shaped to provide a ledge recessed inwardly from the top, whereby the opening provides access to the ledge and the cavity for inspection or maintenance of the base section. Preferably, the bowl portion extends from the ledge further into the body.

Preferably, the body is formed of concrete. More preferably, the body is formed by casting concrete.

In one embodiment the pipes are cast into the concrete body. In the second embodiment holes are cast into the concrete body for the pipes to extend through. In a third embodiment, holes are cored into the concrete body for the pipes to extend through.

Preferably, the holes are formed in the body at an angle so that the pipes passing through the holes may be disposed at a desired angle relative to one another. Alternatively, the pipes are cast in the body at a desired angle relative to one another.

Preferably, the top includes a riser recess for recessing a riser that extends upwardly from the base section to allow access to the base section for inspection or maintenance.

Preferably, the ledge slopes inwardly toward the bowl section.

Preferably, the inlet pipe opens into the inlet portion at a relatively higher height to where the outlet exits the bowl portion.

Preferably, the body is generally cylindrical in shape. Alternatively, the body is generally frustoconical in shape. Preferably, the curved surface of the cylinder or frustocone forms the side.

Brief Description of the Drawings In order to provide a better understanding of the present invention, a preferred embodiment will be described in detail, by way of example only, with reference to the

accompanying drawings, in which: Figure 1 is an end view of a preferred embodiment of the manhole base section in accordance with the present invention; Figure 2 is a side view representation of the base section of Figure 1 connected to an inlet pipe and an outlet pipe; and Figure 3 is a top view of the base section of Figure 1.

Detailed Description of the Drawings Referring to Figure 1, there is shown a manhole base section 10 that includes a body 12 having a top 14, a base 16 and a sidewall 18. The body 12 is generally frustoconical in shape with the curved surface forming the sidewall 18. The base 16 is larger in area than the top 14. The top 14 is provided with an opening 20 leading into a cavity 22 that extends into the body 12. The cavity 22 is divided into a recess portion 24 and a bowl portion 26. The bowl portion 26 includes a semi-hemispherical inlet portion 50 and a funnel shaped outlet portion 52. A lower part of the bowl portion 26 forms a sump.

A sidewall 28 and ledge 30 boarder the recess portion 24. The sidewall 28 is directed substantially downwardly from the top 14 and slopes slightly inwardly until it meets the ledge 30. The ledge 30 is substantially horizontal, although it slopes slightly downwardly towards the bowl portion 26.

The inlet portion 50 is defined by a hemispherical wall 32. The hemispherical wall 32 is sloped so that the inlet portion 50 is provided with a single drainage or collection point 34.

Fluid within the bowl moves, under the force of gravity, down the sloping hemispherical wall 32 to the drainage point 34. The drainage point 34 is at an interface with the outlet portion 52.

The outlet portion 52 is defined by opposite walls that are disposed at an acute angle to

one another and curved channel shaped bottom wall. Fluid in the drainage point 34 is channelled between the opposed walls of the outlet portion 52, through the channel shaped bottom wall to an outlet 48.

The periphery of the top 14 forms a lip 36 within which there is provided a riser recess 38.

The riser recess 38 extends inwardly from the lip 36 to a riser ledge 40. The riser ledge 40 is provided so that a riser (not shown) may sit on the ledge 40 within the riser recess 38, so as to provide a passage to the manhole to allow access to the base section for inspection or maintenance.

Referring to Figures 2 and 3, an inlet pipe 42 is shown extending through the sidewall 18 into the inlet portion 50. The inlet pipe 42 is slightly downwardly sloping so as to encourage, under gravity, fluid or slurry within the pipe into the bowl section 26. The inlet pipe 42 opens into the inlet portion 50 at opening 44. The opening 44 is higher relative to than the substantially flat bottom surface of the bowl 34, so that fluid or slurry from the inlet pipe 42 flows down the bowl wall 32 to the bottom surface of the bowl 34. An outlet pipe 46 also extends from the sidewall 18 into the inlet portion 50. The outlet pipe 46 has a downward slope leading from the outlet 48 of the bowl 34 so that fluid or slurry is encouraged to flow, under gravity, from the inlet portion 50 out through the funnel shaped outlet portion 52 to the outlet pipe 46. The outlet 48 is positioned at the narrow end of the funnel shaped portion of the bowl so that fluid or slurry flowing down the bowl wall 32 or along the bottom surface of the bowl 34 will then flow on from the bottom surface 34 into the outlet pipe 46. The outlet 48 is thus lower than the opening 44 of the inlet pipe 42.

Referring to Figure 3, it can be seen that the inlet pipe 42 and the outlet pipe 46 are disposed relative to one another at an angle? which is approximately 180. The position of the pipes relative to one another may be provided at any desired angle. Common angles will be 120, 135*, 150 and 180. Additional pipes may be added leading from the sidewall 18 into the inlet portion 50.

If additional pipes are added, providing inlets to the inlet portion 50, they should always be

provided at a height greater than the opening 48 of the outlet pipe 46 so that liquid or slurry always flows from the inlet pipe/s toward the bottom surface of the bowl 34 and then out through the outlet pipe 46.

The body 12 is generally formed of cast concrete. The pipes may be provided by either casting them into the concrete, or by casting holes in the concrete through which the pipes may be inserted and grouted into position. Alternatively, holes may be bored through the body to provide a passage for the pipes. If the pipes are required to be at a particular non- standard angle they may either be precast into the concrete or holes may be precast or the holes may be cored so that the pipes may be inserted. Otherwise set angled base sections may be prefabricated and stored ready for later use.

The method and operation of the present invention will now be described with reference to the accompanying drawings.

The manhole base section is positioned within the ground. The incoming pipes are connected as the inlet and additional inlet pipes, and an outgoing pipe is provided as an outlet pipe 46. The outlet pipe may be larger in diameter than the inlet pipe and additional inlet pipes so as to allow adequate flow. A riser is inserted into the riser recess and rests on the riser ledge 40. The riser is generally then covered with a manhole that allows access through the riser to the base section for inspection or maintenance of the base section or pipes leading to and from the bowl portion. Soil is back filled around the base section.

In use, fluid or slurry enters the bowl portion through the first or further pipes, the slurry then flows down the bowl wall 32 to the bottom surface of the bowl 34, whereupon it then flows through the funnel shaped portion of the bowl 52, to the outlet pipe opening 48 and out through the outlet pipe 46.

The skilled addressee will realise that the present invention provides the following advantages: pipes may be provided at any desired angle relative to one another; the funnel

shaped portion of the bowl results in a more highly directed fluid or slurry flow from the inlet pipe to the outlet pipe. Furthermore, the funnel shape allows for easier access for inspection/maintenance.

Modifications and variations can be made to the present invention without departing from the basic inventive concept. Such modifications may include forming the body of the base section of a material other than concrete; the number of inlet or indeed outlet pipes may be more than that shown in the drawings; the angle of the inlet pipe to the outlet pipe may be other than that shown in the drawings; the shape of the base section may be other than the frustoconical shape; and/or the riser recess may be replaced with a riser projection if the riser has a female receptor, rather than a male projection.

Such modifications and variations are intended to be within the scope of the present invention, the nature of which is to be determined from the foregoing description.