GB2318081A

GB2318081A - Casting a drainage channel block

Info

Publication number: GB2318081A
Application number: GB9621154A
Authority: GB
Inventors: Peter Alexander Jennings; Robert James King
Original assignee: Aco Technologies PLC
Current assignee: Aco Technologies PLC
Priority date: 1996-10-10
Filing date: 1996-10-10
Publication date: 1998-04-15
Anticipated expiration: 2016-10-10
Also published as: GB2318081B; GB9621154D0

Abstract

A drainage channel block is cast in a mould 10, 12, 14, 16 using a sacrificial plastics liner (22) which defines a through bore (4) of the resulting block. Openings and passages to communicate with the bore are formed by sections (24) of the liner. The liner (22) is supported on projections (28) on the inner surface of walls of the mould during the casting process. The liner, or parts thereof, may be removed after the casting material has set.

Description

CASTING PROCESS The present invention relates to a method of casting or moulding hollow objects such as drainage channel sections in one piece.

Drainage channels may be manufactured from polymer concrete and are typically constructed from a U shaped channel member with a separate cover member. In some applications the cover is fitted to the channel so that a one piece channel is supplied for installation on site as, for example, in the case of the Aco Technologies Plc ACO SLIMLINE (registered trade mark) product. A typical drainage channel section comprises a block through which a drainage bore runs from one end to the other. The bore is open at each end face of the block. Additional openings are also provided in the block which communicate with the main bore via internal passages. In the ACO SLIMLINEs product there is just one additional opening which is a simple slot along the upper surface of the block. However, for more complex drainage applications such as kerbs at the side of road carriageways more complex opening configurations are required. Such openings may be in the upper surface of the block and also at the side surface of the block depending upon the application. When such blocks are cast in polymer concrete the structure of the internal cavity is usually such that using conventional methods they must be cast in at least two pieces which are then secured together.

The present invention is intended to solve the technical problem of this multi-part casting process and thereby produce one piece blocks in a single step that are more convenient to transport and need less skill to install.

A method of casting a drainage channel block, which block defines a through bore extending between open ends formed in opposite end faces of the block, and additional openings defined in an outer surface of the block and communicating internally with said bore by means of passages, in accordance with the invention comprises the steps of: providing a mould which defines the outer surface of the block; mounting a hollow plastics liner defining the shape of said bore within said mould and having sections which define the additional openings and passages; and filling the mould with a casting material.

An embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a block made in accordance with the method; and Figure 2 shows a mould for casting the block of Figure 1.

The method of the present invention can be used for forming many different configurations of drainage channel blocks. As shown in Figure 1 a block 2 has a central drainage channel which is a bore 4 extending from one end face of the block to the other. Additional openings 6 are spaced along one long face of the block and communicate with the bore 4 via passages 8.

The block 2 can be cast using a mould as shown in Figure 2. The mould has four walls 10, 12, 14, 16 which each define one face of the block 2. The walls are supported against a base 18 which forms the upper surface of the finished block. In order to mould the bore 4 and the passages 8, a sacrificial plastics liner 20 is provided.

The liner 20 is assembled from a pipe 22 shaped to the size of the bore 4. The passages 8 to be defined in the finished block are formed by hollow sections 24 of the same plastics material. These sections 24 communicate with the pipe 22 and their open faces 26 are pressed against the adjacent wall 14 of the mould to prevent entry of casting material during the moulding process and to define the openings 6 in the finished block. The assembly of pipe 22 and sections 24 is supported above the base 18 of the mould by projections 28 on end walls 12, 16. Each projection engages in a respective open end of the pipe to locate it in position.

The pipe 22 and sections 24 of the liner 20 are made of a plastics material such as styrene, low density polyethylene, ABS or uPVC. The thickness of the walls of the liner 20 is in the range 0.5 to 3 mm, preferably 1.5 mm. The material of the liner 20 must be sufficiently rigid to withstand the crushing pressure of the wet casting material. In order to form complex internal shapes the liner 20 may be formed in two or more separate pieces.

When the mould is closed the ends of the sections 24 will contact the wall 14 and the liner 20 is supported within the mould spaced from the side walls 10, 14 and base 18.

Once the mould is closed it is filled with a casting material in a conventional manner from the open top surface. Suitable casting materials are polymer concrete, OPC, GRC or reconstituted stone. The mould may be vibrated to ensure that it is completely filled. If casting material seeps between the ends of the sections and the walls only a relatively thin skin of material will be formed which can be readily removed after the block is removed from the mould.

The liner 20 preferably remains in position in the completed block. In some embodiments using several sections 24 these parts may be removed. In such embodiments the removable parts of the liner need not be hollow. If the block is cast from a material that leaves rough surfaces the presence of the liner ensures a smooth finsih to the bore 4 and passages 8 to improve hydraulic flow. This allows a greater range of materials to be used for such blocks.

Claims

1. A method of casting a drainage channel block, which

block defines a through bore extending between open ends formed in opposite end faces of the block, and additional openings defined in an outer surface of the block and communicating internally with said bore by means of passages; said method comprising the steps of: providing a mould which defines the outer surface of the block; mounting a hollow plastics liner defining the shape of said bore within said mould and having sections which define the additional openings and passages; and filling the mould with a casting material.

2. A method as claimed in claim 1, wherein the liner is made of a styrene, low density polyethylene, ABS or uPVC.

3. A method as claimed in claim 1 or 2, wherein the liner is made of plastics material having a thickness in the range 0.5mm - 3.Omm.

4. A method as claimed in any one of the preceding claims, wherein the liner of part of the liner is removed after the casting material has set.

5. A method of casting a drainage block substantially as herein described with reference to the accompanying drawings.

6. A drainage channel block manufactured according to the method of any one of the preceding claims.