Silt barrier

Abstract

A silt barrier comprises a plurality of filter elements, each filter element, in use, having a height direction, a width direction and a length direction and being adapted to allow the passage of water therethrough in the width direction and to resist the passage of silt therethrough in the width direction. In an embodiment the filter medium comprises a single type of material which combines: (a) filtration characteristics adequate to provide an effective silt barrier and; (b) deformation/resilience characteristics adequate to allow said filter element to return substantially to its original height after being compressed in its height direction by a vehicle passing thereover.

1 . A modular unit for a silt barrier, the unit comprising:
 at least one filter element 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 silt therethrough in the width direction; and   a ground engageable base to which the at least one filter element is attached, in use, whereby the at least one filter element projects upwardly from the base when the base is engaged with the ground, the filter element being resiliently deformable downwardly in order to allow passage of a wheeled vehicle thereover, and such as to substantially recover its height after such deformation so that the integrity of a silt barrier of which the modular unit is a part, is maintained.   
     
     
         2 . (canceled) 
     
     
         3 . A modular unit for a silt barrier as claimed in  claim 1  wherein the at least one filter element is compressible downwardly in order to allow passage of a wheeled vehicle thereover. 
     
     
         4 . A modular unit for a silt barrier as claimed in  claim 3  wherein the at least one filter element is resiliently deformable downwardly towards the ground engageable base. 
     
     
         5 . A modular unit for a silt barrier as claimed in  claim 4  wherein at least one filter element comprises a block of filter material. 
     
     
         6 . A modular unit for a silt barrier as claimed in  claim 5  wherein the ground engageable base provides a substantially planar lower surface adapted to lie substantially flat upon the ground in use. 
     
     
         7 . (canceled) 
     
     
         8 . A modular unit for a silt barrier as claimed in  claim 1  wherein the ground engageable base is discrete from the filter element, and the at least one filter element is permanently attached thereto in use. 
     
     
         9 . (canceled) 
     
     
         10 . A modular unit for a silt barrier as claimed in  claim 1  wherein the ground engageable base is discrete from the filter element, and the at least one filter element is temporarily attached to the ground engageable base. 
     
     
         11 . A modular unit for a silt barrier as claimed in  claim 10  wherein at least one filter element is attached to a connection element, which is adapted to connect to the ground engageable base. 
     
     
         12 . A modular unit for a silt barrier as claimed in  claim 11  wherein the connection element and the base comprise respective interlocking connection parts comprising at least one projection on one of the connection element and the ground engageable base, adapted to be received and retained in one or more respective receiving portions provided on the other of the connection element and the ground engageable base and wherein the one or more respective receiving portions comprise one or more respective recesses adapted to receive one or more respective projections and wherein the or each projection compromises a narrower portion and a wider portion and a corresponding recess com rises a narrower portion and a wider portion, the wider portion of the projection being adapted to be retained in the wider portion of the recess. 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . A modular unit for a silt barrier as claimed in  claim 5  wherein at least one said filter element is formed as a non-woven assembly of loosely looped or coiled strands. 
     
     
         18 . A modular unit for a silt barrier as claimed in  claim 17  wherein the at least one filter element 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. 
     
     
         19 . A modular unit for a silt barrier as claimed in  claim 18  wherein the non-woven assembly of loosely looped or coiled strands comprises an open web of interengaged continuous elongate filaments of resilient thermoplastic polymeric material, welded together at points of mutual contact to form an integrated self supporting structure. 
     
     
         20 . (canceled) 
     
     
         21 . A modular unit for a silt barrier as claimed in  claim 20  wherein a first horizontally extending portion of the integrated structure has a higher concentration of strands than a second horizontally extending portion of the integrated structure. 
     
     
         22 . A modular unit for a silt barrier as claimed in  claim 18  wherein the base comprises a substantially continuous layer of material bonded to at least some of the strands. 
     
     
         23 . A modular unit for a silt barrier as claimed in  claim 18  wherein the one or more strands or filaments are formed of a vinyl. 
     
     
         24 . A modular unit for a silt barrier as claimed in  claim 18  wherein the base is formed by compression and/or heating of part of at least one filter element, or of the same material that forms the filter element, to provide a water impermeable base part. 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . A modular unit for a silt barrier as claimed in  claim 1 , wherein the base is provided with shaped end portions adapted to interlock with shaped end portions of bases of similar adjacent modular units. 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . A modular unit for a silt barrier as claimed in  claim 1  wherein the or each filter element comprises a filter medium comprising a material which combines: (a) filtration characteristics adequate to provide an effective silt barrier and; (b) deformation/resilience characteristics adequate to allow said filter element to be stably self-supporting when supported only at a bottom part thereof and to return substantially to its original height after being compressed in its height direction by a vehicle passing thereover. 
     
     
         31 . A modular unit for a silt barrier as claimed in  claim 1  wherein a plurality of filter elements are provided on a single base. 
     
     
         32 . (canceled) 
     
     
         33 . A modular unit for a silt barrier as claimed in  claim 31  wherein two or more filter elements are arranged in two or more corresponding rows on the base. 
     
     
         34 . A modular unit for a silt barrier as claimed in  claim 33  wherein one or more rows are continuous and extend substantially the entire length of the base. 
     
     
         35 . A modular unit for a silt barrier as claimed in  claim 33  wherein at least one row is formed so that it is not substantially straight. 
     
     
         36 . A modular unit for a silt barrier as claimed in  claim 35  wherein at least one row is periodic or wavelike in form. 
     
     
         37 . A modular unit for a silt barrier as claimed in  claim 36  wherein at least one row has a form selected from: a generally sinusoidal form, a generally square-wave periodic form, a generally triangular-wave periodic form, or a generally saw-tooth periodic form. 
     
     
         38 . A modular unit for a silt barrier as claimed in  claim 33  wherein at least two of the rows are of different heights. 
     
     
         39 . (canceled) 
     
     
         40 . (canceled) 
     
     
         41 . (canceled) 
     
     
         42 . A silt barrier comprising a number of blocks of resilient filter material abutting or connected to form an elongate silt barrier. 
     
     
         43 . (canceled) 
     
     
         44 . A method of constructing a silt barrier comprising:
 providing a number of modular silt barrier units, each of which comprises at least one filter element 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 silt therethrough in the width direction; arranging a plurality of said modular silt barrier units so that each modular silt barrier unit is adjacent at least one other modular silt barrier unit and so that the plurality of modular silt barrier units comprise a silt barrier in a desired location.   
     
     
         45 . (canceled) 
     
     
         46 . A method of constructing a silt barrier as claimed in  claim 44  wherein at least one of the modular silt barrier units comprises a modular unit comprising least one block of material having a width, a height and a length, being adapted to allow passage of water therethrough in the width direction and to resist the passage of silt therethrough in the width direction, the block having a width at least a fifth of its height and adapted, in use, to be supported at a bottom thereof and to be otherwise self-supporting. 
     
     
         47 . A method of constructing a silt barrier as claimed in  claim 46  wherein at least one of the modular silt barrier units comprises a base and at least one filter element which projects upwardly from the base when the base is engaged with the ground, the filter element being resiliently deformable downwardly in order to allow passage of a wheeled vehicle thereover, and such as to substantially recover its height after such deformation so that the integrity of a silt barrier of which the modular silt barrier unit is a part, is maintained. 
     
     
         48 . A method of constructing a silt barrier as claimed in  claim 44  wherein the method further comprises the step of arranging a filter material to extend between at least two adjacent modular silt barrier units. 
     
     
         49 . A method of constructing a silt barrier as claimed in  claim 48  wherein the filter material is arranged to reduce or prevent unfiltered flow of a liquid between said adjacent modular units. 
     
     
         50 . (canceled) 
     
     
         51 . (canceled)