AU2017203950B2 - An access chamber, and components of an access chamber - Google Patents

Abstract

An access chamber, and components of an access chamber An access chamber 1 for a below ground network comprises a base section 2 configured to locate within a ground hole in use and comprising a wall 6 and base 5, the wall 6 extending around and upwards from the base 5, a plurality of apertures 7 formed in and passing through the wall 6; a liner 11 covering at least a portion of the inner surface of the wall 6, the liner comprising an unbroken surface facing into the base section 2, and a plurality of ribs 16 that extend into and embed within the wall 6. (Use figure 1) 4 3 2

Description

3

"An access chamber, and components of an access chamber"

FIELD

The present invention relates to an access chamber for a below ground pipe network. More particularly, the present invention relates to an access chamber for a sewer and/or wastewater system. The present invention also relates to the components for forming an access chamber. The present invention also relates to a method of forming components for an access chamber.

BACKGROUND

Sewage pipes are used to form a network of pipes for carrying liquid and semi-liquid sewage away from the point of entry (e.g. a domestic dwelling) to a main area network, and then to a processing facility. The pipes are almost always buried below ground or street level, with sewer inspection/access points positioned at intervals within the pipe network to allow workers to access the pipes for maintenance or similar. Generally, the sewer inspection/access points are in the form of a chamber with a top end that opens onto the street or at ground level, ingress and egress points for sewer pipes and a lower floor or internal surface that has an open-topped channel or channels that connect the ingress and egress points, and through which sewage flows in use. The floor is usually downwardly sloped to the channel, to assist with drainage and clearing overspills.

Generally, these inspection/access points are required to be robust enough to withstand the pressure of being buried, plus vibration, knocks and jarring from weather, nearby traffic, and similar. Different types of chambers will be specified, depending on the requirements for a particular area. In Australia and in particular in Western Australia, different types of access chambers have different classifications. During building and construction (e.g. when building a new subdivision), chambers of a particular classification will be specified, depending on their location within the network (which will effect how much volume they are required to carry, and how often they will need inspection/maintenance/repair/replacement, etc). The most common type of chamber (defined as type 1 in Western Australia) is a standard, bare concrete pit shaft.

In wastewater environments, bare concrete access chambers (and pipes) are likely to be detrimentally affected and corroded by sulphuric acid gas attack, the gas coming from elements such as ammonia and nitrates in sewer water. The concrete that forms the chamber reacts with the ammonia and nitrates in the sewage, corroding the chamber. It is not unusual in poorly ventilated, enclosed sewerage systems to find significant damage to the inner faces of precast concrete access chambers. This corrosion can result in very severe and costly consequences, to the point where access chambers must be completely replaced or rehabilitated long before their useful design life.

Another potential issue is as follows: it is common for these types of chambers to be formed from multiple elements, such as a base, a riser (the main wall of the chamber), and a top. Where a seal is provided between these items, it usually takes the form of a mastic sealant, the mutual ends of the concrete elements shaped to fit together (for example, a mutually fitting z-shape in profile), with the mastic providing a seal between the two ends. Over time, the seal corrodes and allows plant roots and tree roots to grow through the gap, feeding on the nutrients that are provided by the sewage within the system. As these roots grow, they expand and potentially block and burst the sewer pipes.

One solution to these problems is to line the inspection/access pit with a 2mm to 6mm plastic or PVC coating or liner, with sections of the coating poly-welded together to form a seamless leak-proof surface. PVC liners provide excellent protection of the underlying concrete as PVC is virtually unaffected by sulphuric acid. In Western Australia, fully lined chambers are referred to as Type 6 chambers. This is effective in preventing sewage-based corrosion, but takes a long time to install and is expensive. This solution also does not fully prevent root ingress and the associated damage, and also does not fully seal the inspection/access points against the ingress of external fluids, which flow in and cause corrosion and damage.

Although it is desirable to have fully lined chambers at all locations, in order to avoid the cost of repairs and replacement, there is a substantial cost differential between lined and unlined chambers, and standard access chambers (type 1) are still used where possible in order to save on initial costs.

Summary of the Invention

It is an object of the present invention to provide an access chamber which goes some way to overcoming the above mentioned disadvantages, or which at least provides the public with a useful choice.

It is a further object of the invention to provide the components for forming an access chamber, either singly or in combination, and which go some way to overcoming the above mentioned disadvantages, or which at least provide the public with a useful choice.

It is a yet still further object of the present invention to provide a method of forming components for an access chamber, or which at least provide the public with a useful choice.

The term "comprising" as used in this specification and indicative independent claims means "consisting at least in part of". When interpreting each statement in this specification and indicative independent claims that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

As used herein the term "and/or" means "and" or "or", or both.

As used herein "(s)" following a noun means the plural and/or singular forms of the noun.

Accordingly, in a first aspect the present invention may broadly be said to consist in an access chamber for a below ground network, comprising: a base section configured to locate within a ground hole in use and comprising a wall and base, the wall extending around and upwards from the base, a plurality of apertures formed in and passing through the wall, and; a liner covering at least a portion of the inner surface of the wall, the liner comprising an unbroken surface facing into the base section, and a plurality of ribs that extend into and embed within the wall.

In an embodiment, the access chamber further comprises an upper lip seal configured to cover and run around substantially all of the top rim of the wall, the seal comprising a substantially central channel, extending around substantially the entirety of the lip seal.

In an embodiment, the lip seal extends across the entirety of the top rim, and downwards to overlap the liner on the inwards facing side of the liner.

In an embodiment, the lip seal further comprises a plurality of extensions on the underside thereof that extend downwards into and embed within the wall.

In an embodiment, the wall and base are formed as a unitary item.

In an embodiment, the liner is formed from a plastic material.

In an embodiment, the plastic material comprises PVC polystyrene.

In an embodiment, the liner is substantially 6mm thick.

In an embodiment, the access chamber further comprises a plug configured to locate into the bottom of the base section to cover at least the upper surface of the base.

In an embodiment, the plug comprises at least one channel configured to extend between at least two of the plurality of apertures.

In an embodiment, at least part of the upper surface of the plug is configured to slope downwards towards the channel.

In an embodiment, the plug and liner are formed as a unitary item.

In an embodiment, the plug and liner are formed as separate items.

In an embodiment, the wall and base are formed from concrete.

In an embodiment, the access chamber further comprises a plurality of rebar elements embedded in one or both of the wall and base.

In an embodiment, the rebar elements and lip seal extensions are mutually configured to interlink.

In an embodiment, the access chamber as outlined in any of the dependent statements above further comprises a riser/top section, the riser/top section comprising a tubular body section substantially sized with and configured to locate onto the top rim of the wall, the tubular body section comprising a riser/top section side wall and a riser/top section liner, the liner covering at least a portion of the inner surface of the riser/top section side wall, the liner comprising an unbroken surface facing into the riser/top section, and a plurality of ribs that extend into and embed within the riser/top section side wall.

In an embodiment, the access chamber further comprises a lower edge seal configured to cover and run around substantially all of the bottom rim of the riser/top section side wall, the seal comprising an extension section extending around substantially the entirety of the bottom rim, the extension section substantially the same size and profile as the central channel of the upper lip seal.

In an embodiment, the lower edge seal extends across the entirety of the lower rim of the riser/top section, and upwards to overlap the liner on the inwards facing side of the liner.

In an embodiment, the lower edge seal further comprises a plurality of extensions on the upper side thereof that extend upwards into and embed within the riser/top section side wall.

In an embodiment, the access chamber further comprises an upper edge seal configured to cover and run around substantially all of the top rim of the riser/top section side wall and having a central channel with a profile and size substantially the inverse of the riser/top section lower edge seal.

In an embodiment, the upper edge seal extends across the entirety of the lower rim of the riser/top section, and downwards to overlap the liner on the inwards facing side of the liner.

In an embodiment, the upper edge seal further comprises a plurality of extensions on the underside thereof that extend downwards into and embed within the riser/top section side wall.

In an embodiment, the riser/top section side wall is formed from concrete, and further comprises rebar elements embedded within the riser/top section side wall.

In an embodiment, the rebar elements and extensions are mutually configured to interlink.

In a second aspect the invention may broadly be said to consist in a method of forming an access chamber component, comprising the steps of:

i. positioning rebar elements and a liner in a mould so that once the component is formed, the liner will form at least part of an inner wall of the component, the liner comprising a plurality of ribs on the outwardly-facing side;

ii. pouring concrete into the mould so that the ribs embed within the concrete once cured.

In an embodiment, the method comprises the further step of positioning an edge seal or seals at one or both of the upper rim and/or lower rim of the component.

In an embodiment, the edge seal or seals is/are of the type that has extensions, the method comprising the further step of interlinking the extensions with the rebar elements.

In an embodiment, if the component is a base component, the method comprises the further step of inserting a plastic plug into the base component.

With respect to the above description then, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

BRIEF DESCRIPTION OF THE FIGURES

Further aspects of the invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings which show an embodiment of the device by way of example, and in which:

Figure 1 shows a perspective side view of an access chamber according to an embodiment of the invention, the system formed from three separate sections: a base section; a riser section, and a top section, stacked to form a fully lined tubular access chamber, the main bodies of the sections formed from concrete and having a PVC skin or liner that fully lines the interior of the access chamber when the sections are assembled, the riser section and top section identical.

Figure 2a shows a cross-sectional side view of the access chamber of figure 1 with the base section, riser section and top section assembled and ready for use.

Figure 2b shows an exploded cross-sectional side view of the access chamber of figures 1 and 2, showing detail of the base section, riser section and top section.

Figures 3a and 3b show cutaway side and perspective views of the base section of figures 1 and 2, showing detail of the construction of the base main body and liner.

Figure 3c shows a close up detail cutaway side view of the top edge of the base section, showing detail of the connection between the liner and the main body of the base section.

Figure 3d shows a cutaway perspective view of the base section of figures 3a and 3b, with the lower part filled with a PVC plug, the top edge of the PCV plug meeting the lower edge of the liner, a channel running diametrically across the plug to connect between two diametrically opposed apertures in the side wall of the base portion, the top surface or floor of the plug sloping downwards to the channel.

Figures 4a and 4b show cutaway side and perspective views of the riser section/top section of figures 1 and 2, showing detail of the construction of the main body of the riser section/top section, and the liner.

Figure 4c shows a close up detail cutaway side view of the bottom edge of the riser section/top section, showing detail of the connection between the liner and the main body of the riser section/top section.

Figure 4d shows a close up detail cutaway side view of the bottom edge of the riser section/top section, showing detail of the connection between the liner and the main body of the riser section/top section.

Figure 4e shows a close up detail cutaway perspective view of the top edge of the base, showing detail of the connection between the liner and the main body of the riser section/top section.

Figure 5a shows a perspective cross-sectional view of a mould suitable for forming the base section, the base section moulded upside-down, rebar elements and a plastic liner located within the mould before the concrete is poured so that the concrete sets around the rebar and liner elements.

Figure 5b shows a perspective cross-sectional view of a mould suitable for forming the riser or top section, with a riser/top section located within the mould.

DETAILED DESCRIPTION

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only.

A first embodiment of the access chamber is shown in figure 1. The access chamber 1 is formed from three main components: a base section 2, a riser section 3, and a top section 4. In use, these are connected together to form the sewer inspection/access point or access chamber 1. The way in which these elements are inter-connected will be described in detail below. The three main elements will now be described in detail.

Base Section

The base section 2 of this embodiment is generally circular in plan view, with a wide lower base portion 5, and a slightly inwardly-sloping upstanding wall 6 that extends upwards from the base portion 5. The base portion 5 and the wall 6 are formed from concrete in this embodiment.

The interior of the base section 2 (the bowl section) is in use partially filled with a plug 10 formed from a plastic material coated with polyuria. Two apertures 7 extend through the wall 6, just above the top of the lower base portion 5. The apertures 7 are on generally diametrically opposed sides of the base section 2 in this embodiment. However, these could be at different relative positions (such as for example separated by a 90-degree or 135-degree angle in different embodiments), or there could be three or more apertures for different types of access system.

The apertures 7 are connected by an internal open-topped channel 9 that passes through the plastic plug 10 from one side to the other (again, it should be noted that in variations the channel can be shaped to connect two or more apertures located at different positions). The circumference of the plastic plug 10 extends around halfway up the interior side of the wall 6. That part (approximately the upper half of the interior side wall 6) not covered by the material of the plug 10 is covered by a separate plastic skin or liner 11, approximately 2mm thick. The liner has ribs 16 on the outwards-facing side, that embed within the concrete of the wall 6, the ribs extending for approximately 9mm from the rear face of the wall.

An upper lip seal 12 runs around the top rim of the wall 6. The upper lip seal 12 has a central channel 13 that runs circumferentially around the upper lip seal 12 to form a female connector at the top of the base section 2. The seal 12 extends across the top of the wall 6, and downwards a short distance on the inner and outer surfaces of the wall 6, overlapping the outside of the plastic coating 11 slightly. Rings 17 are positioned at intervals around the underside of the upper lip seal 12, and are interlinked with the upper edge of rebar elements 14 that are embedded in the wall 6, the rings 17 also embedded in the concrete of the side wall 6.

As can be seen in figures 3a, 3b, and 3c, strengthening steel rebar elements 14, 15 are embedded in the wall 6 and base portion 5 of the base section 2, extending substantially vertically within the wall 6 (element 14) and base portion 5, and (as a separate element 15) across the base portion 5 substantially horizontally.

The way in which the base section 2 is formed is as follows:

A mould is formed of the appropriate shape and size, such as for example the mould shown in figure 5a, which has an outer side wall 30 and inner side wall 29, and which allows the base section 2 to be formed upside-down. The rebar elements 14, 15 and plastic coating or liner 11 are located within the mould, the liner 11 located just inside the side wall 29 of the mould, the side wall 29 extending upwards to where the upper surface of the interior of the finished base will be located. The internal plastic plug 10 is not present at this stage, and is inserted afterwards. The upper lip seal 12 is positioned at the bottom of the mould . The rings 17 are interlinked with the rebar elements 14.

Concrete is poured into the mould and allowed to cure, forming the base section 2 when the mould is removed. The plastic coating 11 becomes embedded in the concrete and is held securely in position by the ribs 16.

The mould is removed and the base turned the right way up. The plug 10 can then be inserted readyforuse.

Riser/Top Sections

In terms of construction features, the riser section 3 and top section 4 are substantially identical. Each is tubular, with a substantially circular cross-section. For simplicity, the riser section 3 only will be described in detail below.

The riser section 3 has a concrete side wall 18, with an upper edge seal 19 and a lower edge seal 20, and a liner 24. These are described below.

The lower edge seal 20 of the riser section 3 and the upper lip seal 12 of the base 2 form a male/female pair, with the lower edge seal 20 forming the male part. The lower edge seal 20 has an extension section 21 substantially the same size and profile as the channel 13 of the upper lip seal 12 of the base section 2 that extends downwards from the lower edge of the riser section 3, and which in use fits tightly within the channel 13. The remainder of the lower edge seal 20 extends to each side of the inner end of the extension section 21 to fully cover the lower edge of the side wall 18, the lower edge seal 20 overlapping and extending upwards a short distance on the inner and outer sides of the side wall 18. On the inner side, the lower edge seal 20 overlaps the outside of the plastic liner 24 slightly. On the outer side, the concrete side wall 18 is profiled so that the overlapping part fits within a circumferential notch or groove so that the outer wall of the riser section 3 is smooth - the overlapping part and concrete outer surface are flush.

The upper edge seal 19 has a profile that is the inverse of the lower edge seal 20 (a central female channel 31 rather than an outwards extension part 21). However, in a similar manner to that described above, the upper edge seal 19 overlaps and extends downwards a short distance on the inner and outer sides of the side wall 18. On the inner side, the upper edge seal 19 overlaps the outside of the plastic liner 24 slightly. On the outer side, the concrete side wall 18 is profiled so that the overlapping part of the upper edge seal 19 fits within a circumferential notch or groove so that the outer wall of the riser section 3 is smooth - the overlapping part and concrete outer surface are flush.

Each of the upper and lower seals 19, 20 has rings 23 that extend inwards (i.e. into the side wall 18 - upwards or downwards). Strengthening rebar elements 22 are located in the wall 18, and the rings 23 interlink with these within the concrete wall.

The plastic riser liner 24 is located to fully cover the inner surface of the side wall 18 of the tubular riser 3. The plastic riser liner 24 has a thickness of around 6mm, with ribs 25 covering substantially the entirety of, and extending substantially radially from, the outer surface (radially outwards). As described above, the upper and lower seals 19, 20 each have an inner wall section that extends and overlaps the upper and lower ends/edges of the plastic riser liner 24.

In order to form the riser 3, the liner 24 is located in position in a mould, with the upper and lower seals 19, 20 then positioned in the mould, with the rebar elements 22 between them, and connected via the rings 23. Concrete is poured into the mould and allowed to cure. When the mould is removed, riser 3 is left. The ribs 25 of the liner 24 are embedded in the concrete and held securely in position to hold the liner 24 in position.

In terms of construction features, each of the riser 3 and top section 4 are identical, as noted. However, in normal use, the heights/lengths of each can be varied, and the items mixed and matched as required to accommodate different depths of sewer pipe. For example, the heights/lengths of the riser and top sections 3, 4 could be 300mm, 450mm, 600mm, 900mm, 1200mm and 1500mm to accommodate different hole depths and depending on the depth of the sewer pipe.

Connection

In use, the base 2 is positioned where required in a pre-dug hole. Sewer pipes from the sewer network are connected via their ends to the apertures 7. A riser unit 3 of the appropriate height is located above the base 2, with the extension part 21 extending downwards into the channel 13, and the upper lip seal 12 on the base and the lower edge seal 20 in contact across their outer surfaces of the extension part 21, the channel 9 and the horizontal elements directly to each side of these. Before connection, a layer of glue is added to the channel 13 and/or the extension part 21, and to the horizontal outer surfaces of the upper lip seal 12 and the lower edge seal 20. When the upper lip seal 12 and the lower edge seal 20 are brought together, they are mated and sealed by way of the glue and the tight fit between them. When gluing the male and female seals together, because the mating surfaces are tight and formed from plastic, a seal is formed. Tree roots cannot penetrate this, and moisture does not escape to attract the tree roots. Because the seals are bonded to each other there is a watertight seal and the system is formed as a single piece.

The top portion 4 is positioned on the top of the riser unit 3 in a similar manner to that described above.

In the preferred embodiment, the plastic material used for the liners is PVC. The material used for the seals in the preferred embodiment is polyurethane. The seals 12, 19, 20 can also be formed from rubber, by extrusion as a single length from a die. The seals are then cut to the required length. Post-extrusion and cutting, the seals are slotted, or otherwise cut and manipulated as necessary, in order to fit retaining clips or similar, for the rings 17, 23 to be fitted, to interlink with the rebar elements. The ends of the seal are brought together and glued to one another to form the circular seal, and the seal is then positioned in the mould for concrete pouring as described below.

A system as described above offers advantages in terms of extended useful life, sealing ability, lower maintenance and on-going cost.. It is as advantageous as using a lined chamber, but more efficient to manufacture.

These advantages allow what is effectively a lined system similar to known category 6 or type 6 access chambers to be used in scenarios or locations where unlined chambers (e.g. type 1 chambers) may previously have been used, for a similar cost. This is advantageous as using a lined chamber results in lower maintenance and on-going costs.

Editorial Note 2017203950 Claims pages are unnumbered and should be pages 12-14 Description pages are 1-11

Claims (18)

AU2017203950 - "An access chamber, and components of an access chamber" Claims - Marked-up copy

1. An access chamber for a below ground network, comprising:

a base section configured to locate within a ground hole in use and comprising a wall and base, the wall extending around and upwards from the base, a plurality of apertures formed in and passing through the wall;

a liner covering at least a portion of the inner surface of the wall, the liner comprising an unbroken surface facing into the base section, and a plurality of ribs that extend into and embed within the wall;

an upper lip seal configured to cover and run around substantially all of the top rim of the wall, the seal comprising a substantially central channel, extending around substantially the entirety of the lip seal;

the wall and base formed from concrete, a plurality of rebar elements embedded in one or both of the wall and base, the rebar elements and lip seal extensions mutually configured to interlink.

2. An access chamber as claimed in claim 1 wherein the lip seal extends across the entirety of the top rim, and downwards to overlap the liner on the inwards facing side of the liner.

3. An access chamber as claimed in claim 1 or claim 2 wherein the lip seal further comprises a plurality of extensions on the underside thereof that extend downwards into and embed within the wall.

4. An access chamber as claimed in any one of claims 1 to 3 wherein the wall and base are formed as a unitary item.

5. An access chamber as claimed in any one of claims 1 to 4 wherein the liner is formed from a plastic material.

6. An access chamber as claimed in any one of claims 1 to 5 wherein the liner is substantially 2mm thick.

7. An access chamber as claimed in any one of claims 1 to 6 further comprising a plug configured to locate into the bottom of the base section to cover at least the upper surface of the base.

8. An access chamber as claimed in claim 7 wherein the plug comprises at least one channel configured to extend between at least two of the plurality of apertures.

9. An access chamber as claimed in claim 8 wherein at least part of the upper surface of the plug is configured to slope downwards towards the channel.

10. An access chamber as claimed in any one of claims 7 to 9 wherein the plug and liner are formed as a unitary item.

11. An access chamber as claimed in any one of claims 9 to 11 wherein the plug and liner are formed as separate items.

12. An access chamber as claimed in any one of claims 1 to 11 further comprising a riser/top section, the riser/top section comprising a tubular body section substantially sized with and configured to locate onto the top rim of the wall, the tubular body section comprising a riser/top section side wall and a riser/top section liner, the liner covering at least a portion of the inner surface of the riser/top section side wall, the liner comprising an unbroken surface facing into the riser/top section, and a plurality of ribs that extend into and embed within the riser/top section side wall.

13. An access chamber as claimed in claim 12 further comprising a lower edge seal configured to cover and run around substantially all of the bottom rim of the riser/top section side wall, the seal comprising an extension section extending around substantially the entirety of the bottom rim, the extension section substantially the same size and profile as the central channel of the upper lip seal.

14. An access chamber as claimed in claim 13 wherein the lower edge seal extends across the entirety of the lower rim of the riser/top section, and upwards to overlap the liner on the inwards facing side of the liner.

15. An access chamber as claimed in claim 13 or claim 14 wherein the lower edge seal further comprises a plurality of extensions on the upper side thereof that extend upwards into and embed within the riser/top section side wall.

16. An access chamber as claimed in any one of claims 12 to 15 further comprising an upper edge seal configured to cover and run around substantially all of the top rim of the riser/top section side wall and having a central channel with a profile and size substantially the inverse of the riser/top section lower edge seal.

17. An access chamber as claimed in claim 16 wherein the upper edge seal extends across the entirety of the lower rim of the riser/top section, and downwards to overlap the liner on the inwards facing side of the liner.

18. An access chamber as claimed in claim 16 or claim 17 wherein the upper edge seal further comprises a plurality of extensions on the underside thereof that extend downwards into and embed within the riser/top section side wall.

19. An access chamber as claimed in claim 18 wherein the riser/top section side wall is formed from concrete, and further comprises rebar elements embedded within the riser/top section side wall.

20. An access chamber as claimed in claim 19 wherein the rebar elements and extensions are mutually configured to interlink.

EDITORIAL NOTE

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