WO2001073230A1

WO2001073230A1 - A liner

Info

Publication number: WO2001073230A1
Application number: PCT/GB2001/001269
Authority: WO
Inventors: Graeme Pringle
Original assignee: Cns Networks Limited
Priority date: 2000-03-28
Filing date: 2001-03-23
Publication date: 2001-10-04
Also published as: GB0007370D0

Abstract

A liner for a manhole, inspection chamber or the like comprises superposed sections adjacent ends of adjacent sections being formed in a complementary manner. Each section comprises inner and outer skins joined by a series of spaced webs and a web extending laterally of the webs of the series between the opposite ends of the section. All webs are disposed at right angles to the skins. The arrangement provides a rigid structure capable of resisting pressures placed upon it to a greater degree than hitherto.

Description

A LINER

The present invention relates to a liner. The liner is particularly, but not

exclusively intended for use in manhole inspection chambers and the like.

Liners of this general type are already known. One such is described in

EPA 787861. It comprises a plurality of superposed sections. Whilst this

works well in practice under certain circumstances the web system may not

resist the pressures placed upon it to a sufficient degree.

According to the present invention there is provided a liner for a

manhole, inspection chamber or the like comprising one or more sections

moulded from a synthetic plastics material, the or each section comprising

inner and outer skins joined by a system of webs to provide a substantially

rigid deformation resistant structure, the opposite ends of which are formed to

interlock with any adjacent section, in which the system of webs comprises a

series of spaced webs extending between the inner and outer skins and

substantially between the said opposite ends and a web extending laterally of

the series of webs and disposed between the said opposite ends.

In a preferred embodiment of the invention all of the webs extend at

right angles to and between the inner and outer skins. The or each section is

compression moulded preferably from glass reinforced plastic (GRP), sheet

moulding compound (SMC) or bulk moulding compound (BMC). One end of

the section is rebated to form a projection which extends all the way around the periphery of the section and the other end of the section is formed in

complementary manner. In this way superposed sections can be interlocked,

the projection of one section interlocking with the complementary formation of

the section directly adjacent it. In an installation of the liner, the lowermost

section would sit on a prepared base usually of concrete and a lid would be

placed over the uppermost section. The undersurface of the lid would

advantageously be provided with a complementary formation to that of the

upper surface of the uppermost section. The laterally extending web defines

a plurality of apertures which enable the amount of moulding material used and

the weight to be reduced. The or each section may comprise a number of sub¬

sections which may be disassembled for transport and reassembled on site.

Adjacent sub-sections may be joined together through complementary

interengaging projections and apertures. Joints may be disposed at the corners

of a section and at points along one or more walls of the section.

In order that the invention may be more clearly understood embodiments

thereof will now be described, by way of example, with reference to the

accompanying drawing, in which :-

Figure I is a perspective view of a liner section showing internal structure.

Figure 2 is a plan view of the liner section shown in figure 1 ,

Figure 3 is a partial view in cross-section of the liner section of figure 1,

and Figure 4 is a diagrammatic view of a modification.

Referring to the drawing the liner may comprise one or more sections.

In the latter case, sections are superposed and fit together in a manner to be

described later. The depth of the or each section I, which is compression

moulded from a suitable thermosetting synthetic plastics material such as glass

reinforced plastic (GRP) in sheet moulding compound form (SMC) or bulk,

moulding compound form (BMC), is chosen to give a reasonably flexible

arrangement consistent with current economic moulding practice. The number

o sections is chosen having regard to the depth of the hole/chamber which is

to be lined. Each section has a hollow open ended form. Its external shape in

end, side elevational or plan view may be chosen as desired.

Each section I comprises inner and outer skins 2 and 3 joined together

by a system of reinforcing webs. This system comprises two series. The first

series comprises individual webs 4 which extend between and at right angles

to the inner and outer skins 2 and 3 between the upper and lower edges 5 and

6 of the section. The second series of webs comprises webs 7 which also

extend between and at right angles to the inner and outer skins 2 and 3 but

between adjacent webs 4 of each pair at a position approximately halfway

between edges 5 and 6. The effect of the webs 7 together is to provide a

single web extending laterally completely around the section. This laterally

extending web adds to the rigidity of the section and resists forces tending to collapse the skins 2 and 3 against one another. Its position advantageously

substantially midway between the upper and lower edges 5 and 6 also

facilitates the moulding process, the split-line of he mould being adjacent this

web. Apart from the webs at the four corners of the section, the webs 4 are

equidistantly spaced. The thickness of each web 4 may progressively reduce

from top to bottom of the section. Each web 6 defines an aperture 7a. Each

aperture 7a has an oval shape, but the shape may be varied as desired. The

provision of these apertures 7a enables the amount of moulding material used

to be reduced, thereby reducing expense, it also enables the weight and the

section to be reduced. The apertures also serve as drainage holes enabling any

water penetrating the outer skin 3 to drain away leaving the inside dry.

The upper edges 5 of each section are rebated to produce an

interlocking projection 8 which extends wholly around the upper periphery of

the section. The lower periphery 9 of the section is formed in complementary

manner so that when one section is placed in superposed manner on another

the interlocking projection 8 of the lower section is received within the

complementary periphery 9 of the section immediately above. In this manner

two or more sections can be interlocked together to form a rigid liner of the

required height. A detail cross-sectional view to a larger scale of upper

projection 8, and complementary formation 9 is shown in figure 3 for two

superposed sections 1. An external flange 21 extends around the lower periphery 9. In use of the section this flange acts as a grip for concrete or

earth backfill.

In a modified form each section 1 may be made up from sub-sections.

Referring to Figure 2, each section 1 may have a split 10, 11, 12 and 13 at

each corner so that the section 1 is made up from sub-sections comprising two

end walls 10 and 11 and two side walls 2 and 13. A joint is provided at each

split. In one form this joint comprises an integral projection 18 from one wall

14 which is received in a complementary integral aperture 19 in the adjacent

wall 17. in an alternative form each adjacent end of the walls at the split may

be formed with an aperture and a separate piece comprising oppositely

extending projections 20 positioned with these projections extending into the

adjacent complementary apertures. Such a piece is illustrated diagrammatically

in figure 4. Walls may themselves be split into constituent sub-sections, so that

walls of different length may be built up from these sub-sections. In this way,

transport of larger size sections may be facilitated, the sections being built up

on site.

In use after digging a hole in the ground and preparing the (usually

concrete) base, sections as described above are introduced to build up a liner

to the desired height. The manhole/ inspection chamber so lined may then be

closed off by means of a (usually concrete) lid inside a supporting frame which

may be formed on its undersurface with a formation similar to formation 9 to interlock with projection 8 of the uppermost section. Any peripheral infilling

may then be attended to complete the installation. If desired, the liner may be

installed into preexisting manholes/inspection chambers. The above described

arrangement provides an easily installable corrosion resistant, load bearing yet

light, rigid and deformation resisting structure.

It will be appreciated that the above embodiments have been described

by way of example only and that many variations are possible without

departing from the scope of the invention.

Claims

1. A manhole, inspection chamber or the like comprising one or more

sections moulded from a synthetic plastics material, the or each section

comprising inner and outer skins joined by a system of webs to provide

a substantially rigid deformation resistant structure, the opposite ends

of which are formed to interlock with any adjacent section, in which the

system of webs comprises a series of spaced webs extending between

the inner and outer skins and substantially between the said opposite

ends and a web extending laterally of the series of webs and disposed

between the said opposite ends.

2. A liner as claimed in claim 1 , in which all of the spaced webs extend at

right angles to and between the inner and outer skins.

3. A liner as claimed in claim 1 or 2, in which the laterally extending web

is at right angles to and between the inner and outer skins.

4. A liner as claimed in claim 1, 2 or 3, in which the or each section is

compression moulded.

5. A liner as claimed in claim 4, in which the or each section is

compression moulded from glass reinforced plastic (GRP), sheet

moulding compound (SMC) or bulk moulding compound (BMC).

6. A liner as claimed in any preceding claim, in which one end of the or

each section is rebated to form a projection which extends all the way around the periphery of the section and the other end of the section is

formed in complementary manner.

7. A liner as claimed in any preceding claim, in which the or the upper

most section is provided with a lid.

8. A liner as claimed in claim 7, in which the undersurface of the lid is

provided with a complementary formation to that of the upper surface

of the or the uppermost section.

9. A liner as claimed in any preceding claim, in which the laterally

extending web defines a plurality of apertures.

10. A liner as claimed in any preceding claim, in which the or each section

comprises a number of sub-sections.

11. A liner as claimed in claim 10, in which adjacent sub-sections are joined

together through complementary interengaging projections and

apertures.

12. A liner as claimed in claim 10 or 1 , in which joints between sub¬

sections are disposed at corners of the section.

13. A liner as claimed in claim 10, 11 or 12, in which joints between sub¬

sections are disposed at points along one or more walls of the section.