NZ763041A - Particulates barrier and related methods and apparatus - Google Patents

Abstract

A modular unit for a silt barrier comprises a main body which, in use, has a height direction, a width direction and a length direction and is adapted to allow passage of water therethrough in the width direction and to resist passage of silt therethrough in the width direction. The main body provides a base region (23A, 23B) for contacting a surface upon which the modular unit is to be located in use, and a recessed region (30) of said base region. des a base region (23A, 23B) for contacting a surface upon which the modular unit is to be located in use, and a recessed region (30) of said base region.

Description

PARTICULATES BARRIER AND RELATED METHODS AND APPARATUS FIELD The present disclosure relates to a particulates barrier and especially, but not exclusively to a modular particulates barrier for use as a silt barrier. The present disclosure extends to a method of manufacturing a particulates barrier, and to a cleaning apparatus for a particulates barrier.

DEFINITION In the specification the term “comprising” shall be understood to have a broad meaning similar to the term “including” and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term “comprising” such as “comprise” and “comprises”.

BACKGROUND Silt barriers are used in various applications, to reduce loss of topsoil, and are often used on construction sites.

Loss of top soil from construction sites, due to the top soil being washed from the site by rainwater or the like is a common problem and is undesirable because it can lead to erosion of the site and large amounts of top soil entering drainage or storm water systems, and natural waterways or bodies of water potentially causing substantial degradation in water quality.

Silt barriers have been used to reduce the loss of top soil and similar particulates from construction sites and other locations. A type of silt barrier used on constructions sites, which is often known as a ‘silt fence’, comprises a fence-like structure including a flexible sheet of a geotextile material supported by a number of substantially rigid stakes which extend into the ground and which support the geotextile sheet in a generally vertical orientation. The bottom edge of the geotextile sheet may be buried or ‘trenched’ to prevent water flow under the bottom edge.

The type of silt fence described above can suffer from a number of problems in use. For example, if any of the stakes are knocked over, for example, by a vehicle entering or leaving the construction site or other location, the geotextile sheet adjacent the fallen stake will typically lie flat and not serve its intended purpose as a silt barrier. Even if a vehicle passing over the silt fence avoids the stakes, it may substantially flatten the filtration material and/or cause it to become disconnected from one or more of the stakes, rendering at least part of the silt barrier inoperative.

Moving and re-deploying the silt barrier to allow passage of a vehicle without damaging the silt barrier is time consuming and inconvenient. Furthermore, the stakes, being substantially rigid and extending upwardly from the ground may constitute a safety hazard as they may be accidentally walked into or fallen upon.

The reference to prior art or other background in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the referenced prior art [or other background] forms part of the common general knowledge in Australia or in any other country SUMMARY According to a first aspect of the present disclosure there is provided a modular unit for a silt barrier, the modular unit comprising: a main body which, in use, has a height direction, a width direction and a length direction and is adapted to allow passage of water therethrough in the width direction and to resist passage of silt therethrough in the width direction.

In an embodiment the main body provides a base region for contacting a surface upon which the modular unit is to be located in use, and a recessed region of said base region.

In an embodiment the base region provides a base surface and the recessed region extends from the base surface into the main body.

In an embodiment the recessed region defines a cavity in the main body.

In an embodiment the cavity extends upwardly from the base surface.

In an embodiment the cavity is provided at a substantially laterally central region of the main body.

In an embodiment the cavity is has a length, in the length direction of the main body, and a width, in a width direction of the main body.

In an embodiment the cavity has a length which is substantially greater than its width.

In an embodiment the cavity extends substantially the entire length of the main body.

In an embodiment the cavity extends the entire length of the main body.

In an embodiment the recessed region effectively divides a base surface of the main body into first and second lateral parts.

In an embodiment the recessed region effectively divides a base surface of the main body into first and second laterally spaced apart base surface parts.

In an embodiment an in use lower region of the main body is provided as first and second lateral parts. The first and second lateral part may comprise respective first and second laterally spaced apart main body volumes.

In an embodiment the base surface is terminus or a boundary of a filter material that forms the main body.

In an embodiment substantially the same material and structure that forms the bulk of the main body also forms the base surface.

In an embodiment the base surface is formed of a non-woven open-loop material.

In an embodiment the base surface is configured so as not to prevent passage of water therethrough.

In an embodiment the base surface is porous.

In an embodiment the cavity effectively divides an in use lower region of the main body into first and second lateral parts.

In an embodiment the recessed region effectively divides an in use lower region of the main body into first and second laterally spaced apart main body volumes.

In an embodiment the first and second laterally spaced apart main body volumes are connected by an in use more upper part of the main body.

In an embodiment the provision of the cavity reduces the lateral stiffness of the main body (compared to a main body lacking the cavity but otherwise corresponding) facilitating relative displacement of the first and second laterally spaced apart base surface parts and/or first and second laterally spaced apart main body volumes.

The facilitated relative displacement of the first and second laterally spaced apart base surface parts and/or first and second laterally spaced apart main body volumes may assist in providing a main body with a base region that can conform to an uneven ground surface.

In an embodiment the cavity has a lateral width at least 20% of the lateral width of the main body.

In an embodiment the cavity has a lateral width at least 30% of the lateral width of the main body.

In an embodiment the cavity has a lateral width at least 40% of the lateral width of the main body.

In an embodiment the cavity has a lateral width at less than 80% of the lateral width of the main body.

In an embodiment the cavity has a lateral width at less than 70% of the lateral width of the main body.

In an embodiment the cavity has a lateral width at less than 60% of the lateral width of the main body.

In an embodiment the cavity has a height at least 20% of the height of the main body.

In an embodiment the cavity has a height at least 30% of the height of the main body.

In an embodiment the cavity has a height at least 40% of the height of the main body.

In an embodiment the cavity has a height less than 80% of the height of the main body.

In an embodiment the cavity has a height less than 70% of the height of the main body.

In an embodiment the cavity has a height less than 60% of the height of the main body.

In an embodiment the modular unit provides an upwardly extending portion.

In an embodiment the cavity is dimensioned to receive the upwardly extending portion of a substantially identical modular unit.

In an embodiment the cavity comprises a stacking connection configuration for connection of the modular unit to a substantially identical modular unit in order to facilitate stacking of a plurality of substantially identical units.

In an embodiment the main body is resiliently deformable in the in use height direction to thereby be adapted to allow passage of a wheeled vehicle thereover, and to substantially recover its height thereafter. This may allow the integrity of a silt barrier of which the modular unit is a part, to be maintained.

In an embodiment the unit has a length of at least 0.5 metres.

In an embodiment the unit has a length of at least 1 metre.

In an embodiment the unit has a length of between 0.5 and 5 metres.

In an embodiment the unit has a length of between 1 metre and 3 metres.

In an embodiment the unit has height, in the height direction, of at least 100mm.

In an embodiment the unit has height, in the height direction, of at least 200mm.

In an embodiment the main body is compressible downwardly in order to allow passage of a wheeled vehicle thereover.

In an embodiment the main body comprises a filter material.

In an embodiment the main body is resiliently deformable downwardly to a height no more than half its undeformed height and to resiliently recover its substantially undeformed height after such deformation.

In an embodiment the main body is resiliently deformable downwardly to a height no more than quarter its undeformed height and to resiliently recover its substantially undeformed height after such deformation.

The main body may be formed as a non-woven assembly of loosely looped or coiled strands.

In an embodiment the main body comprises a multiplicity of bonds, each bond being a bond between a point on a strand and another point on the same, or a different, strand.

In an embodiment the one or more strands of material are formed of a polymer material.

In an embodiment the one or more strands of material are formed of a plastic.

In an embodiment the one or more strands of material are formed of a vinyl.

An example of a material, comprising one or more strands configured in a loose looped configuration, which can be used as the primary material of the main body is that used for vinyl non-woven matting material. An example of such a material is that used in scraper matting sold by 3M under the trade mark NOMAD (although when used for matting the vinyl strand non-woven material is typically provided as a layer approximately 1cm high which is unsuitable for use as a silt barrier in the embodiments described herein).

The non-woven assembly of loosely looped or coiled strands may comprise an open web of interengaged continuous coarse elements of resilient thermoplastic polymeric material, welded together at points of mutual contact to form an integrated structure.

At least one major surface of the integrated structure may be flattened.

A first horizontally extending portion of the integrated structure may have a higher density of strands than a second horizontally extending portion of the integrated structure.

The first horizontally extending portion of the integrated structure may be closer to a bottom of the main body than is the second horizontally extending portion of the integrated structure.

The strands may have a diameter of between about 5 and about 200 thousandths of an inch (about 0.013mm to about 0.5mm).

In an embodiment, the modular unit comprises a lengthwise connection arrangement.

In an embodiment, the lengthwise connection arrangement is adapted to allow substantially end-to-end connection of the modular unit to another modular unit having a complementary lengthwise connection arrangement.

In an embodiment the lengthwise connection arrangement is adapted to allow substantially end-to-end connection of the modular unit to another substantially similar modular unit.

The lengthwise connection arrangement may comprise at least one of two respective interlocking lengthwise connection parts.

At least one said lengthwise interlocking connection part may comprise at least one connection projection for engagement into a complementary connection receiving portion a lengthwise connection arrangement.

In an embodiment the cavity extends though the connection projection.

At least one said lengthwise interlocking connection part may comprise at least one receiving portion for engagement of a complementary connection projection of a lengthwise connection arrangement of another modular unit.

The receiving portion may comprise a configuration comprising a connection recess.

The or each connection projection may comprise a narrower portion and a wider portion.

The or each connection recess may comprise a narrower portion and a wider portion.

In an embodiment, the wider portion of the connection projection is adapted to be retained in the wider portion of the connection recess.

In an embodiment the connection projection is be adapted to be retained in the complementary recess in use, and to be removable therefrom, to disconnect a first modular unit from another modular unit.

In an embodiment the connection projection is substantially continuous with the main body.

In an embodiment the connection projection is formed integrally with the main body.

In an embodiment the connection projection extends from an end of the main body.

In an embodiment the connection projection extends into an end of the main body.

In an embodiment the unit comprises a guide portion provided along an in-use lower region of a lateral side of the unit.

In an embodiment the guide portion is adapted to contact a ground surface upon which the unit is placed and to guide water into the main body.

The guide portion may comprise a skirt portion of the unit.

The guide portion may extend laterally beyond a lateral side of the main body.

The guide portion may extend along a lateral side of the main body.

At least part of the guide portion may comprise a water impermeable lateral region.

At least part of the guide portion may comprise a water impermeable lateral region of the skirt portion.

In an embodiment the water impermeable lateral region extends in the length direction of the main body.

In an embodiment the water impermeable lateral region extends substantially the entire length of the main body.

In an embodiment the water impermeable lateral region is spaced apart from the main body.

In an embodiment the water impermeable lateral region is attached to the main body by a flexible attachment.

In an embodiment the flexible attachment is substantially continuous with the main body.

In an embodiment the attachment is made from the same material as the main body.

In an embodiment the water impermeable lateral region has a lateral width of at least 20 mm.

In an embodiment the water impermeable lateral region has a lateral width of at least 30 mm.

In an embodiment the water impermeable lateral region has a lateral width of at least 40 mm.

In an embodiment the water impermeable lateral region has a lateral width of at least 50 mm.

In an embodiment the water impermeable lateral region is tapered across its width.

In an embodiment the water impermeable lateral region is tapered across its width to provide a lesser thickness at laterally outward region and a greater thickness at a laterally less outward region.

The tapered region may provide a bevelled edge which extends in a length direction of the unit.

The water impermeable lateral region may be formed as a solid layer.

In an embodiment he solid layer comprises vinyl or other plastics or rubber material.

The water impermeable lateral region may be formed by compression and/or heating of material which is, during manufacture, part of a body which is provides the main body.

The water impermeable lateral region may be formed by compression and/or heating of strands which form part of an open web of interengaged strands to form at least some of the strands into a substantially continuous, substantially water impermeable region.

In an embodiment the guide portion is permanently attached to the main body.

In an embodiment the guide portion is integrally formed with the main body.

In an embodiment the bevelled edges are adapted to facilitate flow of fluid towards the main body.

In an embodiment the modular unit is adapted to be stably self-supporting when supported only at a bottom part thereof.

In an embodiment, the width of the main body is sufficiently great compared to the height of the main body to allow the modular unit to be stably self-supporting when lying on a substantially horizontal surface.

In an embodiment the width of the main body is at least one half of the height of the main body.

In an embodiment the width of the main body is at least as great as the height of the main body.

According to a second aspect of the present disclosure there is provided a particulates barrier comprising a plurality of modular units in accordance with the first aspect.

In an embodiment the particulates barrier is a silt barrier.

The silt barrier may further comprise a sheet filter material.

In an embodiment the sheet filter material comprises a fabric.

In an embodiment sheet the filter material comprises a geotextile.

The sheet filter material may be attached to one or more units so as to mutually secure two or more adjacent units.

The sheet filter material may be attached to one or more units so to bridge one or more connection regions between adjacent units.

The sheet filter material may be arranged over a surface of main body to enhance resistance to passage of particulates.

In an embodiment the silt barrier comprises a covering for at least a part of at least one main body, the covering comprising a filter material to enhance the resistance of the silt barrier to passage of particulates. At least part of the covering may overlie one or more surfaces of a main body. In an embodiment the covering comprises a sheet filter material, which in particular embodiments is a fabric and/or a geotextile material.

According to a third aspect of the present disclosure there is provided a method of providing a particulates barrier comprising: providing a number of modular particulates barrier units, each of which comprises a main body which, in use, has a height direction, a width direction and a length direction and is adapted to allow the passage of water therethrough in the width direction and to resist the passage of particulates therethrough in the width direction; and arranging a plurality of said modular particulates barrier units so that each modular particulates barrier unit is adjacent at least one other modular particulates barrier unit and so that the plurality of modular particulates barrier units provide a particulates barrier in a desired location.

In an embodiment the method is a method of providing a silt barrier.

In an embodiment each modular particulates barrier unit is a modular silt barrier unit.

In an embodiment at least one of the modular silt barrier units comprises a modular unit in accordance with the first aspect of the present disclosure.

In an embodiment the method further comprises the step of arranging a filter material to extend between at least two adjacent modular silt barrier units.

In an embodiment the filter material is arranged to reduce or prevent unfiltered flow of a liquid between said adjacent modular units.

In an embodiment the filter material is a sheet filter material.

In an embodiment the filter material is a flexible sheet filter material.

In an embodiment the filter material is a geotextile.

In an embodiment the method further comprises the step of attaching the filter material to at least one of the modular silt barrier units.

In an embodiment the method further comprises the step of wrapping the filter material at least partially around at least one of the modular silt barrier units.

In an embodiment the method comprises securing at least one modular unit by driving a fixing member through part of the modular unit and into the ground.

In an embodiment the modular unit has a lateral extension extending laterally outwardly from the main body.

In an embodiment the method comprises securing at least one modular unit by driving a fixing member through a part of the modular unit at or adjacent the lateral extension part, and into the ground.

In an embodiment the method comprises securing at least one modular unit by driving a fixing member through the lateral extension part of the modular unit and into the ground.

In an embodiment the lateral extension has a laterally outer part which is more resistant to driving of a fixing member therethrough than is the main body.

In an embodiment the method comprises securing at least one modular unit by driving a fixing member through a part of the modular unit which is laterally inward of the lateral extension, and into the ground.

In an embodiment the fixing member comprises a pin or peg.

According to a fourth aspect of the present disclosure there is provided a method of manufacturing a modular unit for a silt barrier comprising: providing a mould; depositing a thermoplastic into the mould to provide at least a main body part for a silt barrier; removing at least the main body part from the mould.

In an embodiment the main body part is a main body part for a modular unit of a silt barrier.

In an embodiment the method comprises providing the mould with a cavity portion such that thermoplastic provided into said cavity portion forms a projection which in use extends upwardly from said main body part.

In an embodiment the method comprises providing the mould with a shape which provides a cavity in the main body part.

In an embodiment the method comprises depositing said thermoplastic into the mould as one or more strands.

In an embodiment the method comprises depositing said thermoplastic into the mould as one or more strands, so that the main body part comprises a non-woven assembly of loosely looped or coiled strands.

In an embodiment the method comprises treating the at least part of a non-woven assembly of loosely looped or coiled strands by at least one of heating and compression.

In an embodiment the method comprises treating the at least part of a non-woven assembly of loosely looped or coiled strands by at least one of heating and compression to provide a substantially continuous plastic material.

In an embodiment the method comprises treating the at least part of a non-woven assembly of loosely looped or coiled strands by at least one of heating and compression to provide a substantially continuous plastic material at at least one laterally outer part of the silt barrier.

In an embodiment the laterally outer part projects outwardly from the main body part.

In an embodiment the method comprises cutting the main body part to provide a number of main bodies.

In an embodiment the cutting of the main body part substantially simultaneously forms a first end of a first modular unit and a second end of a second modular unit.

In an embodiment the cutting substantially simultaneously forms a first end of a first modular unit having a first lengthwise connection configuration and a second end of a second modular unit having a complementary lengthwise connection configuration.

In an embodiment the method is a method of manufacturing a modular unit in accordance with the first aspect.

According to a fifth aspect of the present disclosure there is provided a cleaning apparatus for a silt barrier comprising: at least one support region for supporting a modular unit of a silt barrier; and at least one fluid outlet for projecting pressurised fluid onto or into the modular unit of a silt barrier.

In an embodiment the at least one fluid outlet is provided above the support region.

In an embodiment the cleaning apparatus is for cleaning a modular unit which has a recess in a base region thereof, and the fluid outlet is arranged, relative to the least one support region, to extend into the recess when the modular unit is supported on the least one support region.

In an embodiment the apparatus comprises a collection arrangement for collecting fluid used for cleaning the modular unit after use.

In an embodiment the collection arrangement comprises a tray or tank.

In an embodiment the apparatus comprises a fluid re-use arrangement for conveying fluid from the collection arrangement to the fluid outlet.

In an embodiment the apparatus comprises a cover adapted to overlie the fluid outlet.

In an embodiment the fluid reuse arrangement comprises a filter arrangement.

In an embodiment the fluid reuse arrangement comprises a pump arrangement.

In an embodiment the support region comprises a plurality of supports.

In an embodiment the support region comprises at least one roller.

In an embodiment the support region comprises a plurality of substantially parallel rollers.

In an embodiment the at least one roller is supported by at least one roller support member.

In an embodiment the at least one roller is supported between two roller support members.

In an embodiment a rolling surface of at least one roller extends above said at least one roller support member.

In an embodiment the cleaning apparatus has a length direction and a width direction, and the support region is configured to facilitated movement of a modular unit in the length direction of the cleaning apparatus.

In an embodiment the support region has a first-side region and a second-side region spaced apart from the first side region.

In an embodiment the fluid outlet is provided between the first- and second-side regions of the support region.

In an embodiment the cleaning apparatus is configured to receive an in-use upwardly extending projection of a modular unit in the space between the first- and second- side regions of the support region.

In an embodiment the cleaning apparatus is provided on or in a portable transport unit.

The portable transport unit may be, for example, a truck, a trailer or a transportable container, such as a shipping container or similar.

In an embodiment the cleaning apparatus is adapted for use without removal from the portable transport unit.

In an embodiment the cleaning apparatus is provided so that a length direction of the cleaning apparatus, and/or a direction of movement of a modular unit during cleaning thereof, is substantially transverse to the portable transport unit.

In an embodiment the cleaning apparatus is provided so that a length direction of the cleaning apparatus, and/or a direction of movement of a modular unit during cleaning thereof, extends between a modular unit ingress region of the portable transport unit and a modular unit egress region of the portable transport unit.

The ingress and egress regions of the portable transport unit may be respective side openings of a truck, trailer or container.

It will be appreciated that features described in relation to one or more of the above aspects may be incorporated in one or more of the other aspects.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments will be described below, in detail, with reference to accompanying drawings. The primary purpose of this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect.

However, it is to be clearly understood that the specific nature of this detailed description should not be considered to supersede the generality of the preceding Summary section. In the accompanying diagrammatic drawings: Figure 1 is a schematic illustration of an embodiment of a particulates barrier comprising several modular units connected end-to end, in accordance with the present disclosure; Figure 2 is a schematic top plan view of an embodiment of a single modular unit of the particulates barrier of Figure 1; Figure 3(a) is an end view of the embodiment of Figure 2 from a first end thereof; Figure 3(b) is an end view of the embodiment of Figure 2 from a second end thereof; Figure 3(c) is a side view of a part the embodiment of Figure 2 at and adjacent the second end; Figure 3(d) is a schematic transverse cross sectional view on D-D of Figure 3(c); Figure 4(a) is a schematic perspective view of the embodiment of Figures 2 and 3 from the first end; Figure 4(b) is a schematic perspective view of the embodiment of Figures 2 and 3 from the second end; Figure 5 is an enlarged transverse cross sectional view of the embodiment of Figures 2 to 4; Figure 6 is a schematic cross sectional illustration of two modular units having the cross sectional form illustrated in Figure 5 stacked, to provide increased height; Figure 7 is a schematic transverse cross sectional view of a mould for use in manufacturing an embodiment of a modular particulates barrier in accordance with the present disclosure; Figures 8 and 9 illustrate schematically use of the mould of Figure 7 to manufacture an embodiment of a modular particulates barrier in accordance with the present disclosure; Figures 10, 11(a) and 11(b) illustrate schematically a variation of the mould and manufacturing method of Figures 7 to 9; Figure 12 is a schematic plan view illustrating a cutting arrangement for cutting a body of material to form a first end of a first modular unit and a second end of a second modular unit; Figure 13 is a schematic top plan view of an embodiment of a cleaning apparatus for cleaning a modular particulates barrier in accordance with the present disclosure; Figure 14 is a schematic side view of the cleaning apparatus of Figure 13; Figure 15 is a schematic end view of the cleaning apparatus of Figures 13 and 14 in use; Figure 16 is a schematic top plan view of a more compact variation of embodiment of a cleaning apparatus; Figure 17 is a schematic top plan view of another embodiment of a cleaning apparatus for cleaning a modular particulates barrier in accordance with the present disclosure; Figure 18 is a schematic side view of the cleaning apparatus of Figure 17; Figure 19 is a schematic end view of the cleaning apparatus of Figures 17 and 18 in use; Figure 20 is a schematic side view of an embodiment of a vehicle in which the cleaning apparatus of Figures 17 to 19 is provided to provide a mobile cleaning station; Figure 21 is a schematic illustration of the mobile cleaning station of Figure 20; and Figure 22 is a schematic illustration of the modular unit of Figures 2 to 4(b) positioned for use.

DETAILED DESCRIPTION OF EMBODIMENTS With reference to Figures 1 to 6 an embodiment of a particulates barrier, and modular units which can be used to provide a particulates barrier, will now be described.

With reference to Fig. 1 an embodiment of a particulates barrier, in the form of an elongate silt barrier generally designated 10, comprises a number of modular units each comprising a body formed of material through which water can pass, the modular units being adapted to be connected end to end in order to provide the elongate silt barrier 10.

As illustrated in Fig. 1 the silt barrier 10 comprises a first end unit 11, a number of intermediate units, of which a first intermediate unit 12 is illustrated and a second end unit 13.

It will be appreciated that the number of intermediate units used in any particular silt barrier depends on the desired length of the silt barrier.

In the illustrated embodiment each modular unit 11, 12, 13 is substantially identical and thus only one of the modular units will be described in detail hereafter. However, it should be appreciated that in this embodiment each unit 11, 12, 13 comprises a body of material adapted to provide a barrier to silt, but through which water can pass, so as to be adapted to provide a silt barrier for mitigation of soil erosion from construction sites and the like.

With reference to Figs. 2 to 5, one of the units, in this example the intermediate unit 12, will be illustrated and described in more detail. A main body 20 of the intermediate unit 12, in this embodiment, is in the form of an elongate body of filtration material, which is self-supporting. That is, it does not require posts or stakes to maintain the orientation and height of the main body 20. In this embodiment the main body 20 has a width dimension, designated X of approximately 400 mm, a length dimension, designated Y, of approximately 1600 mm and a height dimension, designated Z, of approximately 200 mm. It will be appreciated that these dimensions may be varied as desired, for example according to the intended circumstances of use and desired characteristics of the silt barrier.

The main body 20 may be regarded as somewhat cuboid in overall form, and as having an upper surface 22, a base surface 23, first and second side surfaces 24, 25 and first and second end surfaces 26, 27.

The main body 20 is provided with a recess 30 on the underside thereof, which in the illustrated embodiment provides a void which extends substantially the entire axial length of the main body 20 and is located substantially at the transverse centre of the main body 20.

The recess 30 may be regarded as dividing the base surface 23 into first and second side parts 23A, 23B. In the illustrated embodiment the recess 30 defines a void which is substantially square or rectangular in transverse cross section. In the illustrated embodiment the void defined by the recess 30 has a width of about 100 mm (about 4 inches) and extends about 100 mm (4 inches) into the main body. It will be appreciated that in this embodiment the height of the recess or void is approximately half the height Z of the main body 20, so that the void may be regarded as dividing the lower part, or half, of the main body into two laterally spaced apart volumes 20A, 20B, as illustrated in Figure 5, which is a transverse cross sectional view taken through an axially central part of the modular unit 12.. In the illustrated embodiment the two laterally spaced apart volumes 20A, 20B are connected by the part of the main body that is above the void, this being the upper part, or half, 20C of the main body 20.

The main body 20 is provided with an upwardly projecting part 40 which extends upwardly from the upper surface 22 thereof. In the illustrated embodiment the upwardly projecting part 40 extends substantially the entire axial length of the main body 20 and is located substantially at the transverse centre of the main body 20. The upwardly projecting part 40 may be regarded as dividing the upper surface 22 into first and second side parts 22A, 22B. In the illustrated embodiment the upwardly projecting part 40 is substantially square or rectangular in transverse cross section. The dimensions of the upwardly projecting part 40 correspond substantially to those of the recess 30 so that the upwardly projecting part 40 of a lower modular unit can be received in the recess 30 of an upper modular unit facilitating secure stacking of one modular unit upon another, as illustrated schematically in Figure 6 and described in more detail hereafter. The recess 30 and upwardly projecting part 40 may be regarded as examples of lower and upper connection configurations. In the illustrated embodiment the upwardly projecting part 40 has a width of about 100 mm (about 4 inches) and extends about 100 mm (4 inches) above the upper surface 22.

The main body 20 is provided with a connection region at each end thereof to allow modular units to be connected end-to-end.

A first-end connection region 50 provides a shaped recess 52 which extends from the first end surface 26 into the main body 20, in a generally lengthwise direction of the main body 20. The shaped recess comprises a narrower portion 53 closer to the first end surface 26 and a wider portion 56 further from the first end surface 26. In the illustrated embodiment the wider part 56 becomes progressively wider as it extends further from the narrower portion 53 into the main body.

In the illustrated embodiment the shaped recess 52 provides a recess opening part 54, proximal to the first end surface 26, which is wider than the narrower portion 53. The narrower portion 53 of the recess is thus provided between the recess opening part 54 and the wider portion 56, both of which are wider than the narrower portion 53. The recess opening part 54 is defined by recess side surfaces 55. The narrower portion 53 is provided by inwardly extending surfaces 57, each extending laterally substantially less than half the width of the recess opening part 54 so that they provide a central space therebetween, corresponding to the minimum width of the narrower portion 53. The wider portion 56 is defined by diverging side surfaces 58, which diverge laterally outwardly as they extend further from the narrower portion 53 into the main body, and by a terminal end surface 59, which extends between the most widely spaced parts of the diverging side surfaces 58. In the illustrated embodiment each of the recess surfaces 55, 57, 58, 59 extends substantially the entire height of the main body 20 and is oriented substantially in the height direction of the main body.

A second-end connection region 60 comprises an axially projecting part 62, which projects away from the main body 20 and the second end surface 27. The axially projecting part 62 comprises a narrower part 63 closer to the main body 20, and a terminal wider part 66 further from the main body 20.

In the illustrated embodiment the axially projecting part 62 provides a connecting part 64, proximal to the second end surface 27, which is wider than the narrower part 63. The narrower part 63 of the axially projecting part 62 is thus provided between the connecting part 64 and the wider part 66, both of which are wider than the narrower part 63. The connecting part 64 is defined by side walls 65. The narrower part 63 is provided by inwardly extending side wall surfaces 67, each extending laterally inwardly substantially less than half the width of the connecting part 64 so that they provide the narrower part 63 therebetween. The wider part 66 is defined by diverging side walls 68, which diverge laterally outwardly as they extend further away from the main body 20, and by a terminal end wall 69, which extends between the most widely spaced parts of the diverging side walls 68. In the illustrated embodiment each of the wall parts 65, 67, 68, 69 extends substantially the entire height of the main body and is oriented substantially in the height direction of the main body.

In the illustrated embodiment the wider part 66 becomes progressively wider as it extends further from the main body 20. In the illustrated embodiment the axially projecting part 62 is made from the same material as the main body 20. The axially projecting part 62 may be formed integrally with the main body 20 and cut to shape, as will be described in more detail in due course.

The upwardly projecting part 40 overlies the axially projecting part 62.

As illustrated in Figure 3(d) the recess 30 extends through the axially projecting part 62. The connecting part 64 is substantially laterally wider than the recess 30, so that filter material is provided on each lateral side of the recess, extending away from the end surface 27. This avoids the recess 30 intersecting lower parts of the second end surface 27. That is, this avoids the recess 30 and lower parts of the second end surface 27 meeting to provide a straight-line path through the connection between two modular units devoid of filter material.

Such a straight-line path, devoid of filter material, could provide a path along which particulate- bearing water could freely flow from one lateral side of the silt barrier to the other without passing through the filter material.

It will be appreciated that the first end connection region is adapted to connect to the second end connection region of another modular unit to allow the modular units to be connected end to end.

In the illustrated embodiment the first end connection region 50 is adapted to connect to the second end connection region 60 of another substantially identical modular unit. That is, the shaped recess 52 is adapted to receive and retain an axially projecting part 62 of another, substantially identical modular unit.

In the illustrated embodiment the first-end and second-end connection regions 50, 60 are adapted to connect, by movement of the axially projecting part 62 of the second end connection region 60 of a modular unit into the shaped recess 52 of the first-end connection region 50 in a direction corresponding substantially to the height directions of the modular units. The connection will then be resistant to disconnection by relative movement of the modular units in the length direction because the wider part 66 of the axially projecting part 62 is too wide to pass through the narrower portion 53 of the shaped recess 52.

Once connected, modular units will, to some extent overlap in the length direction when placed adjacent each other to form a silt barrier of a desired length. The lengthwise or longitudinal overlap assists in reducing flow of silt-carrying water through any gap between adjacent units. Furthermore, if desired or deemed necessary, a geotextile material may be used to bridge any gap between adjacent units, for example by being attached to and or wrapped around the connected end parts of adjacent units.

It should also be appreciated that during manufacture from a continuous length of material, a generally transverse cut, in a height direction, which forms the first end surface 26 and first-end connection region 50 of a modular unit can also simultaneously form the second end surface 27 and second-end connection region 60 of another modular unit.

The main body 20 is provided with laterally outward extensions 72, 73 which extend laterally outwards from the laterally outermost parts of the base surface 23. The with laterally outward extensions 72, 73 taper so that they are greater in height where they meet the side surfaces 24, 25 of the main body 20, and of minimum height distal from the main body 20, where they provide lateral edges 74, 75 of the modular unit 12.

In the illustrated embodiment the laterally outward extensions 72, 73 provide laterally outermost regions 76, 77 formed of flexible, substantially water impermeable, material and laterally more inward regions 78, 79 where they are made from a material substantially the same as, and continuous with, the material of the main body.

In use, the laterally outermost regions 76, 77 engage the ground upon which the modular unit 12 is placed, so that water flowing in the width direction of the modular unit 12 passes over the laterally outermost regions 76, 77, through the laterally more inward regions 78, 79 and into the main body 20. The laterally outermost regions 76, 77 are intended to assist in preventing water flow under the modular unit 12.

The modular unit 12 is, in use, positioned to form part of a silt barrier 10 such that run-off water, for example rain water draining from a construction site, can pass through the main body 20 in its width direction, and so that silt (which in this context should be considered to include dirt, sand, and other particulate matter which forms soil, or removal of which might contribute to erosion of a land area) is restricted from passage through the main body, by the structure thereof.

In this embodiment the main body 20 is formed from a non-woven, somewhat irregular mesh of vinyl strands, in which points of contact between the strands (or points where a curved strand contacts itself) provide adhesion or other attachment so that the structure of the mesh is maintained. In a particular embodiment the strands are of vinyl, and the open, non-woven mesh structure of the main body 25 is similar in structure to that used in scraper matting such as that manufactured by 3M and sold under the trade mark NOMAD. This material is sometimes referred to as “vinyl loop” material. Vinyl loop scraper matting is known to be resilient in nature, that is, a layer of vinyl loop material typically about 10mm thick, as used in scraper matting, is known to return to its original height after being compressed, for example by being stepped on during use. Details of the structure of, and a manufacturing method for, an open looped material can be found in US Patent No. 3, 837,988, the contents of which are included herein by reference. Of course, it will be appreciated that the structure, or method of manufacture of, the looped material for use in embodiments in accordance with the present disclosure is not limited to the structure or method of manufacture described in that document. The material may comprise a non-woven assembly of loosely looped or coiled strands which form an open web of interengaged continuous coarse filaments of resilient thermoplastic polymeric material, fused together at points of mutual contact to form an integrated structure. A face, or major surface, of the integrated structure may be flattened, for example as part of a manufacturing process, examples of which will be described in due course.

It will be appreciated that the dimensions of the main body 25 are very different to the dimensions of vinyl loop material used in scraper matting. That is, the main body 25 has considerably greater height than the height of vinyl loop material in scraper matting. The increased height assists in preventing run-off water merely flowing over the top of the main body 25. The described embodiment takes advantage of the resilient nature of vinyl loop material to provide a main body 25 which is self-supporting, of simple construction, and is highly permeable to water (allowing good drainage in its width direction) but which can trap particulates carried by the water which passes into the main body 25 in order to act as a silt barrier. Furthermore, the resilient qualities of the material are utilized to provide a silt barrier over which pedestrian or vehicular traffic may pass, so that the block (and thus the silt barrier) can return to its original height quickly after being compressed by passage of such traffic thereover. It should, however, be appreciated that in alternative embodiments the block could be formed from suitable alternative resilient water permeable materials, such as suitable water permeable foam materials known for use as filter media.

Thus, in accordance with embodiments disclosed herein, the main body of a modular unit may comprise a body of said non-woven assembly of loosely looped or coiled strands which form a substantially open web of interengaged continuous coarse filaments of resilient thermoplastic polymeric material.

A first horizontally extending portion of the integrated structure may have a higher concentration of filaments than a second horizontally extending portion of the integrated structure. The first horizontally extending portion of the integrated structure may be closer to a bottom of the main body 25 than is the second horizontally extending portion of the integrated structure. That is, a lower region of the main body 20 may provide a higher density of strands, and consequently smaller spaces between the strands, than a higher region. The filaments may have a diameter of between about 5 and about 200 thousandths of an inch (about 0.013mm to about 0.5mm).

It is envisaged that modular units as described above can provide adequate filtration for at least some silt barrier applications, and can return to substantially their original heights after being deformed and compressed by passage of a person or vehicle thereover.

If it is desired to change the filtration characteristics for a particular set of circumstances, the distribution, thickness or strand density (or other filtration characteristics, especially if a different type of filter medium is used) of the filter medium which forms the main bodies may be changed accordingly.

Further, if desired, the filtration characteristics of one or more of the modular units may be altered after manufacture, for example when forming a silt barrier on site from a number of modular units.

In one example of altering the filtration characteristics, a geotextile (or other) material is attached to one or more of the main bodies. In this case is it preferred that the geotextile (or other) material be attached at least to the upstream face of the or each main body. It has been observed that in use of conventional silt fences, as described above, it is not uncommon for the geotextile material to become clogged with particulate material so that run-off water cannot pass therethrough, and that this can result in a pool or pond of silt bearing water being formed on the upstream side of the silt fence. In these circumstances the particulate material settles over a period of several hours or days, and the water from which the particulate material has settled may then be released, leaving the settled particulate material on the upstream side of the silt fence. Use of a geotextile (or other suitable material) to cover at least the upstream sides of the modular units described above can provide a silt barrier which effects creation of a settling pool as described above, but without some of the disadvantages of a conventional silt fence. For example, the geotextile material is supported by a continuous supporting structure provided by a number of serially connected modular units of the type described above (rather than spaced posts) reducing the likelihood of displacement or rupture of the geotextile by water pressure which could allow unimpeded passage of particulates. Further, the supporting structure provided by a number of serially connected modular units avoids use of potentially hazardous upwardly projecting posts, and avoids or reduces the likelihood of the silt barrier being rendered ineffective by passage of a vehicle thereover or other damage to, or displacement of, the posts.

Further, other suitable supplementary filter media could be included – for example an insert made from a resilient foam filter medium or, if desired, a water impermeable material, could be provided within the recess 30 of the or each modular unit. Such an insert may be dimensioned to fit snuggly in the recess 30.

Figure 6 illustrates schematically, and in transverse cross section, that modular units of the type described above may be stacked in order to provide a silt barrier of increased height. As illustrated in Figure 6, when one modular unit is positioned or stacked on top of another, the upwardly projecting part 40 of the lower modular unit can be received in the recess of an upper modular unit, thereby facilitating secure stacking of one modular unit upon another. Stacking one modular unit upon another can conveniently allow a silt barrier of increased height to be provided using standard modules and alleviates the need to provide differently dimensioned modules in order to provide silt barriers of different heights.

Figures 7 to 9 schematically illustrate, in transverse cross section, an apparatus and method of manufacturing modular units for a silt barrier, for example the modular units 11, 12, 13 described above.

As illustrated in Figure 7 a mould 700 is provided, into which material for forming modular units (such as modular units 11, 12, 13, described above) can be deposited. For embodiments of modular units primarily formed of a non-woven assembly of loosely looped or coiled strands, as described above, a suitable material, such as vinyl, may be extruded, as hot strands, into the mould.

The mould 700 is adapted to form the modular units inverted (or upside down) compared to their in-use orientation. The mould 700 provides a cavity 701 for receiving material. The cavity 701 provides a narrower deeper region 702, a wider intermediate-depth region 704 and shallow laterally outermost regions 705, 706. The mould 700 also provides a void former 707, which is provided at the top of, and in the lateral centre of the wider intermediate-depth region 704.

As illustrated schematically in Figure 8, material 800 is deposited into the mould 700. It will be appreciated from comparison of the shape of the material 800 in the mould cavity 701 and the embodiments of Figures 1 to 6 that material provided into the narrower deeper region 702 forms the upwardly projecting part 40, material provided into the wider intermediate-depth region 704 forms the main body 20, and material provided into the shallow laterally outermost regions 705, 706 forms the laterally outward extensions 72, 73 in a modular unit for a silt barrier manufactured using the mould 700. Material is not able to fill the part of the mould occupied by the void former 707, and the resulting void corresponds to the recess in the manufactured modular unit.

At the stage illustrated in Figure 8, all of the material 800 is in the form of a non- woven assembly of loosely looped or coiled strands, as described above. In order to form the flexible, substantially water impermeable, material of the laterally outermost regions 76, 77, corresponding parts of the non-woven assembly of loosely looped or coiled strands may be compressed (and if necessary heated) to fuse the strands into a substantially continuous form.

Figure 9 illustrates schematically the use of rollers 901, 902 to compress the hot strands in the shallow laterally outermost regions 705, 706 of the cavity against the mould 700 in order to form the laterally outermost regions 76, 77. In this embodiment the parts of the mould 700 defining the shallow laterally outermost regions 705, 706 are inclined to assist in providing the tapered inclined shape of the outward extensions 72, 73.

Figures 10, 11(a) and 11(b) schematically illustrate an alternative apparatus and method of manufacturing modular units for a silt barrier. A mould 1000 corresponds substantially to the mould 700, except that shallow laterally outermost regions 1005, 1006 (corresponding generally to the shallow laterally outermost regions 705, 706 of mould 700) are not inclined.

As shown in Figure 11(a), this results in a partially formed modular unit 1100, in which laterally outermost parts 1105, 1106 are not tapered, but are substantially rectangular in transverse cross sectional shape.

As shown schematically in Figure 11(b), after removal of the partially formed modular unit 1100 from the mould 1000, respective first and second pairs of rollers 1110, 1120, (which may be heated if necessary) are arranged with converging roller surfaces to compress the loosely looped or coiled strands of the laterally outermost parts 1105, 1106 into a substantially continuous form, in order to form the laterally outermost regions 76, 77 of a modular unit.

As foreshadowed above, the moulds 700, 1000 may be used to form a continuous length of partially formed product which may then be cut, in a guillotine action or the like, into desired lengths in order to form modular units for a silt barrier. In a particular embodiment the cuts are made by a blade which has a profile corresponding to the shapes of the ends of the modular units, so that moving the blade in the height direction of the modular units results in a cut which simultaneously forms the first end surface 26 and first-end connection region 50 of a modular unit and the second end surface 27 and second-end connection region 60 of another modular unit.

As foreshadowed above, during manufacture from a continuous length of material, a generally transverse cut, in a height direction, which forms the first end surface 26 and first- end connection region 50 of a modular unit can also simultaneously form the second end surface 27 and second-end connection region 60 of another modular unit. Figure 12 illustrates schematically, in plan view, a blade 1200, which can be used to divide a continuous strip of material into modular units. It will be appreciated that movement of the blade 1200 in the height direction, for example using a press or guillotine type arrangement to make a generally transverse cut across a strip of material (for example moulded as described above) can simultaneously form a first end of one modular unit and a second end of another modular unit while also dividing the strip. In an embodiment the blade 1200 is heated to somewhat melt the material being cut, to reduce the presence of loose disconnected strands at the cut ends of the modular units.

Figures 13 to 15 schematically illustrate an apparatus, generally designated 1300, for cleaning modular units for a silt barrier, for example the modular units 11, 12, 13 described above.

The apparatus 1300 comprises a plurality of supports for supporting a modular unit for a silt barrier, and for allowing the modular unit to be moved across the apparatus. In the illustrated embodiment the supports comprise substantially horizontally oriented rollers 1301 to 1308. The rollers 1301 to 1308 are arranged to provide a substantially planar support region 1310. In the illustrated embodiment there are first to eighth rollers 1301 to 1308 which are supported by a support structure 1320 which comprises a framework of support members arranged to support the rollers 1301 to 1308 therebetween. The support structure 1320 comprises first and second main longitudinal members 1321, 1322 connected by first to fourth main transverse members 1323, 1324, 1325, 1326. Some of the rollers, in this embodiment the first, second, seventh and eight rollers 1301, 1302, 1307, 1308, are supported at their ends by the first and second main longitudinal members 1321, 1322, and thus extend substantially the full transverse width of the support structure 1320. The support structure further comprises first and second secondary longitudinal members 1327, 1328 spaced laterally inwardly from the first and second main longitudinal members 1321, 1322 and located substantially at a longitudinally central region of the apparatus. The third and fourth rollers 1303, 1304 are provided between the first main longitudinal member 1321 and the first secondary longitudinal member 1327 to provide a first-side part 1311 of the support region 1310. The fifth and sixth rollers 1305, 1306 are provided between the second main longitudinal member 1322 and the second secondary longitudinal member 1328 to provide a second-side part 1312 of the support region 1310. The support structure 1320 may further comprises a plurality of legs 1329, or other supports, which in the illustrated embodiment are attached to the main longitudinal members 1321, 1322, to space the support region 1310 above a ground surface.

The apparatus 1300 further comprises a spray outlet arrangement 1330, for projecting pressurised fluid. The spray outlet arrangement 1330 is provided between, and supported by, the first and second secondary longitudinal members 1327, 1328. The spray outlet arrangement 1330 is thus provided between the first-side part 1311 of the support region 1310 and the second-side part 1312 of the support region 1310.

As best illustrated in Figure 14, the spray outlet arrangement 1330 extends above the support region 1310. The apparatus 1300 further comprises pump 1332 in fluid connection with, and for supplying pressurised fluid (typically water) to, the spray outlet arrangement 1330.

As illustrated in Figure 13, in use a modular unit, e.g. modular unit 13, of a silt barrier, is supported on the support region 1310, and on the rollers 1301 to 1308, oriented in an upright or ‘in use’ orientation. When the is modular unit is so supported, the spray outlet arrangement 1330 extends into the recess 30 on the underside thereof. The spray outlet arrangement 1330 directs high pressure water spray into the recess 30, thus flushing out trapped particulates from the main body of the modular unit. The water and flushed particulates may then fall from the modular unit.

The modular unit may easily be moved along the apparatus 1300 on the rollers 1301 to 1308.

As illustrated schematically in Figure 15 the apparatus may further comprise a tray or tank 1340 for receiving the water and flushed particulates falling from, or running off, the modular unit. It will be understood that the particulates should not be released uncontrolled into the environment. The water received by the tray or tank 1340 may be re-used by the pump 1332 and spray outlet arrangement 1330, optionally after filtering by a filter unit 1342.

An outlet 1343 of the filter unit 1342 may be connected to an inlet 1333 of the pump 1332 to facilitate such reuse. Alternatively, or additionally, if the tray or tank 1340 is deep enough to allow sufficiently rapid settling of particulates, water may be selectively drawn from a point near the top of received water to minimise drawn particulates. Although the tray or tank 1340 and the legs 1329 are illustrated schematically as different parts, it should be appreciated that in an embodiment the tray or tank may be used as supports (for example by having the main longitudinal members 1321, 1322 attached to walls of the tank) to space the support region 1310 above a ground surface, as an alternative, or in addition, to the use of legs 1329.

As illustrated in Figures 13 and 14, the apparatus 1300 may include one or more guides, for example vertically oriented rollers 1350, to help guide the modular unit, and in particular to keep the modular unit aligned and centred on the apparatus 1300. In the illustrated embodiment the vertically oriented rollers 1350 are arranged to be located in the recess 30 and to engage the interior vertical walls of the recess 30. Of course, guides other than vertically oriented rollers could be used if desired.

Figure 16 illustrates schematically an alternative apparatus 1600 for cleaning modular units for a silt barrier. The apparatus 1600 corresponds substantially to a longitudinally central region of the apparatus 1300, and therefore provides a more compact cleaning apparatus. The apparatus 1600 comprises first to fourth rollers 1601 to 1604 (corresponding substantially to the third to sixth rollers 1303 to 1306 of the apparatus 1300) and a spray outlet arrangement 1630 and associated pump (not shown) corresponding substantially to the spray outlet arrangement 1330 and associated pump 1332 of the apparatus 1300.

Figures 17 to 19 illustrate a further embodiment of a cleaning apparatus, generally designated 1700.

As will be appreciated from Figures 17 to 19, in view of the above description of Figures 13 to 15, the apparatus 1700 is adapted to receive modular units for a silt barrier (e.g. 11, 12, 13) in an inverted, rather than an in-use upright, orientation.

The apparatus 1700 comprises a plurality of supports for supporting a modular unit for a silt barrier, and for allowing the modular unit to be moved across the apparatus 1700, in the direction of the large arrow 1750. In the illustrated embodiment the supports comprise substantially horizontally oriented rollers 1701, 1702. A first plurality of the rollers 1701 are provided between first and second first-side longitudinal members 1721, 1722, and arranged to provide a substantially planar first-side support region 1710A. A second plurality of the rollers 1702 are provided between first and second second-side longitudinal members 1723, 1724, and arranged to provide a substantially planar second-side support region 1710B. The first-side and second-side support regions 1710A, 1710B are substantially co-planar but are laterally spaced apart. A space 1725 between the first-side and second-side support regions 1710A, 1710B is adapted to receive the upwardly projecting part 40 of the modular units for a silt barrier (e.g. 11, 12, 13) allowing the upper surface parts 22A, 22B of the main body 20 to be supported on the rollers 1701, 1702, and thus the modular units to be conveyed (for example by being pushed or pulled by a user) along the apparatus. In the illustrated embodiment the engagement of the upwardly projecting part 40 in the space 1725 acts to help guide the modular unit, and in particular to keep the modular unit aligned and centred on the apparatus 1700.

As illustrated schematically in Figure 19, the cleaning apparatus may further comprise a fluid outlet arrangement 1730 for spraying high pressure water onto, and into the recess 30 of, the modular units. In the illustrated embodiment the fluid outlet arrangement 1730 comprises a pipe outlet, or spray bar, arrangement 1733 with a plurality of spray nozzles 1734 distributed therealong. The pipe outlet, or spray bar, arrangement 1733 may be configured to, or include an extension part 1735 to, provide spray nozzles 1734 located, in use, within the recess 30 of the modular unit being cleaned. The spray nozzles 1734 may be of a known and commercially available type, and (in all embodiments of cleaning apparatus) may be ‘fan’ type spray nozzles to facilitate distribution of water as desired. The pipe outlet, or spray bar, arrangement 1733 may be arranged transversely relative to the longitudinal direction of the apparatus 1700 (and the direction of movement of the modular units. Of course, if desired two or more such.

The apparatus 1700 may further comprise a canopy 1738, overlying the pipe outlet, or spray bar, arrangement 1733 (and, in use, at least the part of the modular unit being cleaned) to help contain sprayed water (and particulates cleaned from modular units) and guide the contained material into tray or tank 1740. In an embodiment the canopy comprises a part cylindrical sheet of stainless steel, although other materials and shapes may be used as desired and appropriate. Indeed, stainless steel is a preferred material for many of the parts of the cleaning apparatus (such as the rollers and the members, which may be stainless steel c-section or box section). The canopy 1738 may include sidewalls 1739 for further containing and guiding materials, and for supporting the canopy 1738. The fluid outlet arrangement 1730 may be supported by the canopy 1738 and/or sidewalls 1739.

The apparatus 1700 may comprise a filter unit 1742 connected a pump 1332 (which provides pressurised water to the fluid outlet arrangement 1730) to facilitate reuse of water drawn from the tray or tank 1740.

It will be appreciated that the described embodiments of cleaning apparatus 1300, 1700 facilitate efficient cleaning of the modular units, allowing reuse of the modular units, while conserving water by reuse (and optionally, by using collected rainwater) and containing particulates removed from the modular units. The modular units may be manually lifted onto the apparatus (e.g. 1700) and pushed along it, while the actual cleaning is effectively performed automatically by operation of the pump and fluid outlet arrangement (e.g. 1730).

Cleaning of the modular units may be performed on-site.

Figure 20 illustrates the cleaning apparatus 1700 installed on a vehicle such as a truck 2000, to facilitate mobility and transport to a desired location. The cleaning apparatus may be permanently installed on a truck 2000, or a trailer (encompassed by the type of truck illustrated) or may be installed as a demountable unit, for example in a demountable container such as a suitably sized shipping container.

The cleaning apparatus 1700 may be arranged so that the direction of movement of the modular units is transverse to the longitudinal direction of the truck 2000, and the truck may provide openings in its sides. As illustrated in Figure 21, this allows a used and particle- heavy modular unit 2001 to be fed into one side of the truck (or demounted container, indicated by wheels 2004, being absent if a if a demounted container is used, being represented in broken lines), being cleaned as it passes through the truck (or container) in the transverse direction, and emerging as a clean and ready to re-use modular unit 2002.

Figure 22 illustrates a modular unit 12 positioned on-site ready for use on ground 2200 where particulate-bearing water flow is expected.

It should be appreciated that the laterally outward extensions 72, 73 can effectively conform to even an uneven ground surface, preventing or minimising flow of particulate- bearing water under the modular unit 12. In the illustrated embodiment, the laterally outermost regions 76, 77 formed of flexible, substantially water impermeable, material can contact the grounds and guide water flowing in the lateral direction of the modular unit into the main body. The laterally more inward regions 78, 79 attach the laterally outermost regions 76, 77 to the main body and may be regarded as attachments,) and being made from the same material as the main body by being small in cross sectional height are flexible, allowing considerable freedom for the laterally outermost regions 76, 77 to move in the height direction to thereby conform to the ground surface.

Further, the resilient and springy characteristics of the non-woven open-loop material assist in allowing the underside of the modular unit to conform to even an uneven ground surface. In the described embodiments the base surface is merely a boundary of the non-woven open-loop material that forms the main body (rather than consisting of a distinct base material or structure), and can deform to accommodate unevenness in the ground surface.

Further, the recess 30 assists in providing lateral flexibility, allowing some deformation of the modular unit (as illustrated) which further assists in allowing the underside of the modular unit to conform to an uneven ground surface, as illustrated.

In testing it has been found unnecessary to bury or ‘trench’ any part of the modular unit in order to prevent flow of particulate-bearing water thereunder, even on uneven ground, in contrast to the requirements in erecting a conventional silt fence.

The modular units of the type described are generally quite resistant to inadvertent movement, and will normally remain where manually positioned unless deliberately moved.

The open loop structure of the base surface may assist in providing grip (as well as deforming to accommodate irregularities). However, if desired, for example if strong water flow is expected or if it is otherwise desired to secure the modular unit against movement, the modular unit maybe secured in position by driving pins or pegs 2201 through one or more of the laterally outward extensions 72, 73 and into the ground 2200. Pins or pegs may be driven through the laterally outward extensions 72, 73 between the laterally outermost regions 76, 77 and the main body 20 merely by pushing or hammering through the non-woven open-loop material, as needed. Thus, while apertures to accommodate pins or pegs could be performed if desired, such apertures are considered unnecessary.

Figures 23 and 24 are, respectively, a plan view of an end part of a modular unit 12, and a transverse cross sectional view of the modular unit showing example dimensions of various parts and/or features in millimetres, by way of example. Of course, it should be appreciated that the indicated dimensions are by way of example only.

The modular units described therefore facilitate providing silt barrier 10, which is resilient, secure and reusable.

Of course, the above features or functionalities described in relation to the embodiments are provided by way of example only. Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims (29)

1. A modular unit for a silt barrier, comprising: a main body which, in use, has a height direction, a width direction and a length direction and is adapted to allow passage of water therethrough in the width direction and to resist passage of silt therethrough in the width direction.

2. A modular unit in accordance with claim 1, wherein the main body provides a base region for contacting a surface upon which the modular unit is to be located in use, and a recessed region of said base region, wherein the base region provides a base surface and the recessed region extends from the base surface into the main body

3. A modular unit in accordance with claim 2, wherein the recessed region defines a cavity in the main body, said cavity provided at a substantially laterally central region of the main body and extending substantially the entire length of the main bod to effectively divides a base surface of the main body into first and second laterally spaced apart base surface parts.

4. A modular unit in accordance with either of claims 2 or 3, wherein the base surface provides a terminus or a boundary of a filter material that forms the main body, and substantially the same material and structure that forms the bulk of the main body also forms the base surface.

5. A modular unit in accordance with any of claims 2 to 4, wherein the base surface is formed of a non-woven open-loop material.

6. A modular unit in accordance with claim 2 or any of claims 3 to 5 when dependent upon claim 2, wherein the cavity has a lateral width at least 20% of the lateral width of the main body and the cavity has a height at least 20% of the height of the main body.

7. A modular unit in accordance with claim 2 or any of claims 3 to 6 when dependent upon claim 2, wherein the modular unit provides an upwardly extending portion, and wherein the cavity is dimensioned to receive the upwardly extending portion of a substantially identical modular unit to provide a stacking connection configuration for connection of the modular unit to a the substantially identical modular unit, in order to facilitate stacking of a plurality of substantially identical modular units.

8. A modular unit in accordance with any preceding claim, wherein the main body is resiliently deformable in the in use height direction to thereby be adapted to allow passage of a wheeled vehicle thereover, and to substantially recover its height thereafter.

9. A modular unit in accordance with any preceding claim, wherein the modular unit comprises a lengthwise connection arrangement adapted to allow substantially end-to-end connection of the modular unit to another modular unit having a complementary lengthwise connection arrangement, the lengthwise connection arrangement comprising at least one of two respective interlocking lengthwise connection parts.

10. A modular unit in accordance with any preceding claim, wherein the modular unit comprises a guide portion provided along an in-use lower region of a lateral side of the unit, the guide portion being adapted to contact a ground surface upon which the unit is placed and to guide water into the main body, and the guide portion comprising a skirt portion which extends laterally beyond a lateral side of the main body.

11. A modular unit in accordance with claim 10, wherein at least part of the guide portion comprises a water impermeable lateral region of the skirt portion which extends in the length direction of the main body.

12. A modular unit in accordance with claim 11, wherein water impermeable lateral region has a lateral width of at least 20 mm and extends substantially the entire length of the main body.

13. A modular unit in accordance with either of claims 11 or 12, wherein the water impermeable lateral region is attached to the main body by a flexible attachment and wherein the flexible attachment is made from the same material as the main body.

14. A modular unit in accordance with any of claims 11 to 13, wherein the water impermeable lateral region is tapered across its width to provide a lesser thickness at laterally outward region and a greater thickness at a laterally less outward region.

15. A modular unit in accordance with any preceding claim, wherein the modular unit is adapted to be stably self-supporting when supported only at a bottom part thereof.

16. A silt barrier comprising a plurality of modular units in accordance with any one or more of claims 1 to 15.

17. A silt barrier according to claim 16, wherein the silt barrier further comprises a sheet filter material.

18. A silt barrier according to claim 17, wherein the sheet filter material is attached to one or more of the modular units to mutually secure two or more adjacent modular units.

19. A silt barrier according to either of claims 17 or 18, wherein the sheet filter material is attached to one or more modular units to bridge one or more connection regions between adjacent modular units.

20. A silt barrier according to any of claims 17 to 19, wherein the sheet filter material comprises a fabric.

21. A silt barrier according to any of claims 16 to 20, wherein the silt barrier comprises a covering for at least a part of at least one main body, the covering comprising a filter material to enhance the resistance of the silt barrier to passage of particulates.

22. A method of providing a silt barrier comprising: providing a number of modular particulates barrier units, each of which comprises a main body which, in use, has a height direction, a width direction and a length direction and is adapted to allow the passage of water therethrough in the width direction and to resist the passage of particulates therethrough in the width direction; and arranging a plurality of said modular particulates barrier units so that each modular particulates barrier unit is adjacent at least one other modular particulates barrier unit and so that the plurality of modular particulates barrier units provide a silt barrier in a desired location.

23. A method according to claim 22, wherein the method further comprises arranging a sheet filter material to extend between at least two adjacent modular units to reduce or prevent unfiltered flow of a liquid between said adjacent modular units.

24. A method according to either of claims 22 or 23, further comprising securing at least one modular unit by driving a fixing member through part of the modular unit and into the ground.

25. A method according to claim 24, wherein said at least one modular unit has a lateral extension extending laterally outwardly from the main body, and the method comprises securing said least one modular unit by driving the fixing member through a part of the modular unit at or adjacent the lateral extension part, and into the ground.

26. A method of manufacturing a modular unit for a silt barrier comprising: providing a mould; depositing a thermoplastic into the mould to provide at least a main body part for a silt barrier; and removing at least the main body part from the mould.

27. A method according to claim 26 wherein the method comprises: providing the mould with a cavity portion such that thermoplastic provided into said cavity portion forms a projection which in use extends upwardly from said main body part; and providing the mould with a shape which provides a cavity in the main body part; and wherein the method comprises depositing said thermoplastic into the mould as one or more strands, so that the main body part comprises a non-woven assembly of loosely looped or coiled strands.

28. A method according to either of claims 26 or 27 wherein the method comprises cutting the main body part to provide a number of main bodies and wherein the cutting of the main body part substantially simultaneously forms a first end of a first modular unit and a second end of a second modular unit, wherein the first end of the first modular unit has a first lengthwise connection configuration and the second end of the second modular unit has a complementary lengthwise connection configuration.

29. A cleaning apparatus for a silt barrier comprising: at least one support region for supporting a modular unit of a silt barrier; and at least one fluid outlet for projecting pressurised fluid onto or into the modular unit of a silt barrier; wherein apparatus comprises a collection arrangement for collecting fluid used for cleaning the modular unit after use and a fluid re-use arrangement for conveying fluid from the collection arrangement to at least one said fluid outlet.