GB2216916A

GB2216916A - Drainage inspection chamber

Info

Publication number: GB2216916A
Application number: GB8907672A
Authority: GB
Inventors: John Edmund Mcaleer
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-04-05
Filing date: 1989-04-05
Publication date: 1989-10-18
Also published as: GB8907672D0; GB8807902D0

Abstract

An inspection chamber (10) for a drainage system has a cylindrical chamber body (11) with multiple pipe connections (12) for drainage pipes extending outwardly at one end. The pipe connections (12) communicate with each other within the interior (14) of the chamber body (11). Each connection (12) comprises coaxial first (15) and second (16) axially displaced cylindrical parts, the first part (15) preferably having a smaller diameter than the second part (16). The connections can be cut between the parts (15, 16) so that the resulting diameter corresponds to the diameter of the drainage pipes. <IMAGE>

Description

INSPECTION CHAMBER This invention relates to inspection chambers for drainage systems.

It is a conventional practice to provide inspection chambers at regular intervals along the pipework of a drainage system for inspection and rodding purposes.

Such inspection chambers comprise a cylindrical chamber disposed substantially vertically in the ground and having a plurality of pipe connections extending outwardly of the chamber at the lower end thereof. Both the inspection chambers and the drain pipes which are connected to the pipe connections thereof have been made of a clay material for very many years. For some thirty to forty years drain pipes have been made of a plastics material and in more recent years some inspection chambers have been made of a plastics material.

Conventionally the clay drain pipes are of certain specified diameters so as to allow cooperating fitment of new and old drain pipes in a drainage system.

Conventipnally also the drain pipes of plastics material are also of certain specified diameters, but these specified diameters are different from those of the clay drain pipes. In consequence, a builder's merchant must stock several sizes of inspection chamber, and chambers of both clay and plastics materials so as to cater for the particular requirements of each customer requiring such chambers for inclusion in different drainage systems. Alternatively the builder's merchant must stock one type and range of sizes of inspection chamber for either clay or plastics material pipes, and a stock of suitable adaptors to allow cooperating fitting of the chambers in his stock with the drain pipes other than those for which such chambers are intended.

In addition, the use of such adaptors leads to the increased possibility of either drain leakage or drain blockage due to the increased number of joints and pipe ends involved.

It is an object of the present invention to provide an inspection chamber, the use of which avoids, at least to a substantial extent, the abovementioned disadvantages.

The invention provides an inspection chamber for a drainage system comprising an elongate cylindrical chamber body having adjacent one end thereof a plurality of pipe connections extending outwardly thereof and communicating with each other within the interior of said chamber body, wherein each pipe connection comprises a first cylindrical part having a first internal diameter and coaxial therewith but axially displaced therefrom a second cylindrical part having a second internal diameter which is different from said first diameter.

Preferably said inspection chamber is of a plastics material.

Preferably said first cylindrical part extends between said chamber body and said second cylindrical part, and said second diameter is larger than said first diameter. A cutting location may be provided between said first and second parts, and said cutting location may be defined by an annular groove extending around the outer surface of said pipe connection.

Each pipe connection may be formed by moulding and may be formed having a closed end remote from said chamber body, in which case a cutting location may be provided adjacent said closed end and said cutting location may be defined by an annular groove extending around the outer surface of said pipe connection adjacent said closed end thereof.

Said chamber body may comprise a cylindrical wall having a plurality of axially spaced annular corrugations therein. Successive corrugations in a direction away from said one end may be of progressively reduced dimensions. Said corrugations may be of part circular form in cross-section.

Successive corrugations in said direction may be of reduced maximum outer diameter providing an outer taper to said chamber body in said direction. Each of said corrugations may be of equal minimum internal diameter providing a constant minimum internal diameter of said chamber body along its length.

An end region of said chamber body remote from said one end may have a plurality of axially spaced annular grooves extending therearound to provide cutting locations for said chamber body.

One embodiment of inspection chamber in accordance with the invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a side elevation, Fig. 2 is a sectional plan on line Z-Z of Fig. 1, and Fig. 3 is a side elevation, partly in section, of a pipe connection of the inspection chamber of Figs. 1 and 2 to an enlarged scale.

Referring now to the figures there is shown an inspection chamber 10 comprising an elongate cylindrical chamber body 11, which in use is located in a substantially vertical disposition in the ground, with a plurality of pipe connections 12 at the lower end 13 thereof. In this particular embodiment, six pipe connections are provided, but other members and/or relative dispositions of the pipe connections from those shown could be provided if desired.

Two of the pipe connections 12 shown in Fig. 2 have been omitted from Fig. 1 for reasons of clarity. The pipe connections 12 communicate with each other within the interior 14 of the chamber body 11, as shown in Fig. 2.

Each pipe connection 12 is shown in greater detail in Fig. 3, and is of cylindrical form comprising a first part 15 and a second part 16. The first part 15 has a first internal diameter dl suitable for receiving therein a particular standard size of plastic pipe, and extends between the chamber body 11 (not shown in Fig. 3) and the second part 16. The second part 16 is coaxial with the first part 15 but is axially displaced therefrom, and has a second internal diameter d2 which is greater than di and is suitable for receiving therein a particular standard size of clay pipe.

The inspection chamber 10 is rotary moulded of a plastics material for example polyethylene, and is formed such that each pipe connection 12 has a closed end 17 remote from the chamber body 11. Adjacent the closed end 17 around the outside surface of the pipe connection 12 is an annular groove 18 providing a cutting location.

In addition, a second annular groove 19 is provided around the outside surface of the pipe connection 12 between the first and second parts 15,16 to provide a second cutting location. If the particular pipe connection 12 is to be coupled with a clay drain pipe, the closed end 17 of that pipe connection 12 is cut off at the cutting groove 18. The clay pipe is then introduced into the second part 16 of the pipe connection 12. If however the pipe connection 12 is to be coupled to a drain pipe of a plastics material, the pipe connection 12 is cut at the second annular cutting groove 19 so that the second part 16 and the closed end 17 are removed and the plastic pipe is introduced into the first part 15.

By means of the invention it will be necessary for a builder's merchant to stock only a single range of inspection chambers to cater for use with drain pipes of either clay or plastics material. The need for stocking and use of adaptors is also avoided.

As can be seen in Fig. 1, the chamber body 11 comprises a cylindrical wall 20 having a plurality of axially spaced annular corrugations 21 therein. In this embodiment three such corrugations 21 are shown, but other numbers of corrugations may be provided if desired. Also each corrugation 21 is of part circular cross-sectional configuration, but other configurations of corrugation may be provided if desired. Successive corrugations 21 in a direction away from the lower end 13 of the inspection chamber 10 are of reduced dimensions, i.e. radius r,r' in the embodiment shown. In consequence, the largest curved corrugation 21 is provided at the greater depth in the ground where ground pressure on the chamber body is greatest, and the smallest curved corrugation 21 which requires less plastics material is provided at the least depth in the ground where the ground pressure on the chamber body is the least. By this means an adequately strong inspection chamber 10 is provided with the minimum quantity of plastics material to minimise the cost of the inspectibn chamber 10. In addition, the chamber body 11 is formed to have an upwardly directed outer taper, or wedge shape, by arranging that the maximum outer diameter D, D', of successive corrugations 21 in the upward direction are progressively less, whilst each corrugation 21 is of equal minimum diameter d.The taper or wedge shape of the chamber body 11 provides that it is stronger and more stable under compressive loadings than is the case with conventional constant diameter inspection chambers.

To facilitate the cutting of the chamber body 11 to the required length appropriate for the depth of the drainage system below ground level, the upper region 22 of the chamber body 11 is formed having a plurality of axially spaced annular grooves 23 extending therearound.

The axial extent of the region 22 is sufficient to cater for the typical range of lengths of inspection chambers 10 required, and each groove 23 provides a cutting location to facilitate the cutting of the chamber body 11 in a plane substantially perpendicular to the axis of the body 11. The inspection chamber described above may be rotary moulded as previously stated. However, it may be injection moulded or formed by any other suitable process if preferred.

Claims

1. An inspection chamber for a drainage system comprising an elongate cylindrical chamber body having adjacent one end thereof a plurality of pipe connections extending outwardly thereof and communicating with each other within the interior of said chamber body, wherein each pipe connection comprises a first cylindrical part having a first internal diameter and coaxial therewith but axially displaced therefrom a second cylindrical part having a second internal diameter which is different from said first diameter.

2. An inspection chamber according to claim 1 wherein said chamber is of a plastics material.

3. An inspection chamber according to claim 1 or 2 wherein said first cylindrical part extends between said chamber body and said second cylindrical part, and said second diameter is larger than said first diameter.

4. An inspection chamber according to any one of claims 1 to 3 wherein a cutting location is provided between said first and second parts.

5. An inspection chamber according to claim 4 wherein said cutting location is defined by an annular groove extending around the outer surface of said pipe connection.

6. An inspection chamber according to any one of claims 1 to 5 wherein each said pipe connection is formed by moulding.

7. An inspection chamber according to any one of claims 1 to 6 wherein said pipe connection is formed having a closed end remote from said chamber body.

8. An inspection chamber according to claim 7 wherein a cutting location is provided adjacent said closed end.

9. An inspection chamber according to claim 8 wherein said cutting location is defined by an annular groove extending around the outer surface of said pipe connection adjacent said closed end thereof.

10. An inspection chamber according to any one of claims 1 to 9 wherein said chamber body comprises a cylindrical wall having a plurality of axially spaced annular corrugations therein.

11. An inspection chamber according to claim 10 wherein succesive corrugations in a direction away from said one end are of progressively reduced dimensions.

12. An inspection chamber according to claim 40 or 11 wherein said corrugations are of part circular form in cross section.

13. An inspection chamber according to claim 11 or 12 wherein successive corrugations in said direction are of reduced maximum outer diameter providing an outer taper to said chamber body in said direction.

14. An inspection chamber according to any one of claims 10 to 13 wherein each of said corrugations are of equal minimum internal diameter providing a constant minimum internal diameter of said chamber body along its length.

15. An inspection chamber according to any one of claims 1 to 14 wherein an end region of said chamber body remote from said one end has a plurality of axially spaced annular grooves extending therearound to provide cutting locations for said chamber body.

16. An inspection chamber substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.