Patent Application
20090095946
The present invention is directed to the field of construction equipment and more particularly to silt fencing for soil retention.
The present invention is directed to a silt fence comprising a plurality of posts mounted on or in the ground, a fence panel, an apron panel, and a plurality of configurable barrier sections. The fence panel comprises a fence toe, wherein the fence toe is adapted to be buried in the ground. The apron panel has a back edge and an apron toe, the back edge being attached to the fence panel along a length of the fence panel and proximate the fence toe. Each of the plurality of configurable barrier sections has a panel edge and an apron edge, the panel edge attachable to the fence panel perpendicular to the length of the fence panel and the apron edge attachable to the apron panel perpendicular to the first edge of the apron panel. Further, the fence panel is adapted to be connected to the plurality of posts such that the fence panel is maintained in a substantially vertical position and the apron panel extends from the fence panel and is adapted to rest on the ground.
In an alternative embodiment, the present invention is directed to a barrier section for use with a silt fence comprising a substantially vertical fence panel. The barrier section comprises a barrier plate, a base plate, and at least one securing prong. The barrier plate is oriented substantially vertical and has a vertical edge. The base plate is secured substantially perpendicular to a bottom edge of the barrier plate. The at least one securing prong extends down from the base plate and is adapted to secure the configurable barrier section to the ground.
In yet another embodiment, the present invention is directed to a method for manufacturing a silt fence comprising a fence panel, an apron panel and a plurality of configurable barrier panels. The method comprises the steps of a) attaching a back edge of the apron panel to the fence panel proximate and parallel to a bottom edge of the fence panel, b) attaching a first edge of one of the configurable barrier panels to the apron panel and the fence panel, and c) repeating step b) for each of the plurality of the configurable barrier panels at a predetermined separation from another one of the plurality of configurable barrier panels. The attaching step a) will have defined a connection line where the apron panel is attached to the fence panel and a fence toe representing a portion of the fence panel between the connection line and the bottom edge of the fence panel. The attaching step b) will attaching the configurable barrier panel to the apron panel and the fence panel perpendicular to the connection line and from a first point proximate a front edge of the apron panel to a second point proximate a top edge of the fence panel. The attaching step b) will also have defined an apron toe representing a portion of the apron panel between the first points and the front edge of the apron panel.
Silt fences are often used on construction sites or the like to prevent sediment runoff from leaving the site and entering natural drainage way or storm drainage systems. The fence operates to slow storm water runoff and causes the deposition of sediment along the fence. Silt fencing encourages sheet flow and reduces the potential for development of rills and gullies. The basic design of silt fencing has changed little since it was introduced nearly a century ago.
Ideally, the standard silt fence, excluding approximately 10 feet on each end, is installed along the contour lines of the job site. The end sections may be turned slightly uphill. The goal is to form a slow draining catch field for the water-silt mixture (runoff that forms during a rainfall event (i.e., time is given for the silt to settle out of the runoff). In practical terms, rarely is the silt fence installed on the contour, either because of cost or because of the desire to install the fence along the boundary of the work site. However it is installed, problems often occur even in minor rainfall events.
A first problem is that the weight and momentum of the runoff over stresses the fence and posts along the fence, which can fail the fence by physically knocking the fence down. The result is that the silt fence fails and allows the runoff to flow over the silt fence resulting in contaminated water flowing downstream in the water shed. A second problem occurs when the runoff flows to the fence, and then begins to flow along the fence. This parallel flow along the fence tends to result in erosion near the toe of the fence washing out the back fill which frees the bottom of the silt fence allowing water to freely flow under the fence. As before, the result is that the silt fence fails and contaminated water continues to flow downstream. Another problem can arise where the soil may build up along the silt fence or at particular points such that the deposited sediment blocks a substantial portion of the fence making the fence ineffective in trapping additional soil. Therefore, periodic cleaning of the fence to remove this accumulated soil is required to maintain effective functioning of the fence. The various inventions contained in this disclosure are intended to address various aspects of these failure mechanisms. These inventions greatly minimize these problems and have a number of additional advantages.
As will be discussed in more detail below, the silt fence of the present invention is composed of a fence panel, an apron panel, and multiple configurable flow barriers spaced periodically along the fence. The flow barriers are attached to the apron along the bottom and the fence along the side producing a fence with a plurality of barriers perpendicular to the fence panel. In this configuration, water with eroded soil (runoff) will accumulate or pond on the uphill side of each flow barrier. This ponding effect provides time for the water to filter through the fence. As the water filters through the fence the majority of the eroded soil will be filtered from the water and remain just uphill of each barrier. These and other features to be discussed provide a substantial improvement over standard fence.
With reference now to the drawings in general and to
The configurable barrier sections 16 allow the present invention to be installed across contour lines and retard flow in two directions. This design gives the effectiveness of having many small silt fences installed across the contour of the ground, but the installation ease of having one continuous silt fence with significantly improved manufacturing and cleaning capability while the apron reduces the risk of toe erosion.
The filter fence panel 12 is preferably made of a water permeable material and held in place using a plurality of posts 22 mounted on or in the ground. The posts 22 shown in
The apron panel 14 is a horizontal section that runs along and over the ground. The apron panel 14 is also made of a water permeable material, though its permeability may be less than that of the fence panel 12 to minimize erosion beneath the apron panel. The apron panel 14 comprises a back edge 30 and a front edge 32, generally parallel to each other, and is characterized by a length. The back edge 30 of the apron panel 14 is attached to the fence panel 12 proximate the bottom edge 26 of the fence panel and adjacent the fence toe 28. The apron panel 14 is attached in this manner, a sufficient distance from the bottom edge 26, to allow the fence toe 28 to be buried in the ground during installation as mentioned above. The apron panel 14 then extends from the fence panel 12 so that it may rest on the ground surface. The apron panel 14 and the fence panel 12 are thus maintained substantially perpendicular to each other. The front edge 32 of the apron panel 14 comprises an apron toe 34 that is buried in the ground. The apron toe 34 will greatly minimize the possibility of runoff underflow problems along the fence 10, because water will flow onto the apron 14 before it begins to flow parallel to the fence.
In many situations, burying the fence toe 28 and the apron toe 34 may be difficult. Preferably, the fence toe 28 will be buried as shown in
Alternatives to burying the fence toe 28 and the apron toe 34 are contemplated. For example, short stakes at predetermined intervals may be used to pin the fence toe 28 or apron toe 34 to the ground. In high wind situations where the stakes are insufficient to hold down the silt fence 10 between stakes 22, a stiffening member could be located along an edge of the toes 28 and 34. Another option for a stiffening member is a permanently attached rope which is stretched between stakes. Other types of stiffening members could be used in place of the rope such as placing a low cost board or other like acting material along the edge of the toe 28 or 34. Use of a board would tie down or prevent the toe 28 or 34 from blowing up in a windy condition.
A further alternative for securing the fence 28 toe is to have a second tail (not shown) that is generally left on the soil surface of the fence toe during installation of the apron toe 34. Then in a second operation, an installation crew would move along the fence 10 and cover the tail with a shallow mound of soil to prevent wind from getting under the apron panel 14 from the fence toe 28. One skilled in the art would also realize that a combination of each of several of these alternatives could be used to improve holding down the silt fence 10.
With continued reference to
Referring now to
The barrier panel 40 shown in the embodiment of
Alternatively, the attachment site 50 may comprise a draw string (not shown) for securing the attachment site to the post 22. In this alternative embodiment, the second base side 48 of the trapezoidal barrier panel 40 comprises a hem to form a pocket for a draw string or other tie. The hem is preferably formed by creating a fold in the barrier panel 40 parallel to the second base side 48 and securing the second base side to the barrier panel. The draw string or other tie is passed through the hemmed pocket and used to secure the attachment site 50 to the post 22.
Alternative shapes for the barrier panel 40 are contemplated. For example, the barrier panel 40 could take the form of an isosceles triangle. In such a case the base of the triangle would again comprise the apron edge 38 and the fence edge 36, to be attached to the apron panel 14 and the fence panel 12 respectively. A vertex of the panel 40 opposite the base would comprise the attachment site 50. The attachment site 50 would preferably comprise a grommet for use with a tie to secure the barrier panel to the post. The isosceles triangle shape would function similar to the trapezoidal shape discussed previously, while reducing the material needed for the barrier panel 40 and limiting the flap 56 of material when the barrier panel is in the barrier position.
Yet another alternative shape for the barrier panel 40 comprises a right triangle with a base of the triangle secured to the apron panel 14 and the attachment site 50 comprising a grommet at the vertex opposite the base attached to the apron panel. In such a case the barrier panel 40 would have no permanent attachment to fence panel 12. Once the silt fence 10 is installed in the ground and attached to the posts 22, the barrier panel 40 is be raised into place and attached to one of the posts. The attachment site 50 preferably comprises the grommet as discussed previously. Alternatively, the attachment site 50 may comprise an attachment tab. The attachment tab may consist of a reinforced section defining a pocket for receiving the post. The pocket may be slid on top of the post for holding the barrier panel in the barrier position.
Referring now to
Preferably, the barrier plate 62 defines a plurality of slots 72 proximate the base plate 64. The slots 72 function to allow water to pass through the barrier plate 62, while the flow of soil runoff past or through the barrier plate is retarded. As an alternative or in addition to the plurality of slots 72, the barrier plate 62 may define a pass through opening 74 to which a removable and water permeable bag or catch basin (not shown) could be attached. As the bag becomes filled with soil runoff, the bag can be removed and emptied before the silt fence 10 fails. The use of such a bag provides an alternative for the cleaning feature of the configurable barrier 16.
The base plate 64 defines the apron edge 38 of the configurable barrier section 16. The base plate 64 is preferably designed to allow the barrier plate 62 to stand vertically with the base plate on the ground. More preferably, the base plate 64 comprises at least one securing prong 76 extending down from the base plate. The at least one prong 76 is adapted to secure or attach the configurable barrier section 16 to the apron panel 14. The prong 76 will preferably be used to pass through the material of the apron panel 14 and into the ground, securing the position of the barrier panel 16.
Continuing with reference to
The post plate 82 comprises a vertical edge 90 that is provided to support the fence panel 12 of the silt fence 10. Preferably, the vertical edge 90 of the post plate 82 will comprise a plurality of securing hooks 92. The securing hooks 92 allow for the material of the fence panel 12 to be secured to the post 80. The hooks 92 also provide for the barrier plate 40 of the configurable barrier section 16 to be secured to the post 80. One skilled in the art will appreciate the present embodiment allows for the barrier plate 40 to be disengaged from the post 80 and removed temporarily to allow for cleaning of the silt fence 10.
Other alternatives for posts 80 mounted on the ground and not needing to be driven in the ground are anticipated. For example, alternative stakeless posts include: the use of “L” stands weighted with sandbags or small spikes; tripod legs for post stands; and stiff members (e.g., wire, composite, wood) bonded to the fence and held vertical using tension members (e.g., guide wires, cables, ropes).
In addition to the varied stakeless post options, the present invention contemplates alternative structure for posts 22 secured in the ground that would support the fence panel 12. As stated previously, one of the major complaints from silt fence installers is that installing the posts is very labor intensive. The process typically involves stapling, nailing and/or screwing the silt fence 10 fabric to the post. With reference now to
Turning now to
Yet another alternative embodiment for posts 122 for the silt fence 10 is shown in
Another aspect of the present invention contemplates the manufacture of the silt fence 10 as described with regard the embodiment of
The fence panel 12 raw material would typically be purchased in bulk rolls. In most respects it would be similar to any common silt fence 10 material in that it would be permeable to water flow but able to filter fine particles of a particular size from the water. However it would preferably be a premium version of fence material as is commonly available on the market today. It would preferably be purchased in large rolls of greater than several thousand feet in each roll and may be already cut to the proper widths.
The apron panel 14 could be made from similar raw material as the fence panel 12, but would preferably be made to be much less permeable material to water flow. The apron panel 14 is preferably cut and handled in a similar way as the fence panel 12. The apron panel 14 would typically be purchased already cut to the desired width and in large rolls of several thousand feet.
The configurable barrier section 16 raw material would typically be similar to the fence panel 12 material, or could be made from a third material with different properties such as permeability, strength, weight, etc. Note that in some instances, one could envision different materials being used depending on the requirements of the job for which it will be applied or for marketing purposes where a premium fence might use more costly raw materials than a more economical fence. These differences would likely be reflected in performance and the needs of the particular application.
Fence panel 12 material, apron panel 14 material and barrier section 16 material may be selected to optimize their properties for a specific intended application or job and may be similar or dissimilar depending on said application. Said selection could be done by Engineering Specification (described below) for a specific customer and application. For the purposes of this discussion, they are assumed to be of a woven material similar in configuration to standard silt fence material but may be made from different thickness fabric or woven in a tighter weave to increase filtering. From testing it has been found that mixing different materials can improve the efficiency of the silt fence 10.
Engineering Specification can be defined as an engineering analysis to specifically specify selection of component materials based on the engineered analysis for final use of the product. For example, in certain soils one type of material may produce a superior filtering result over another material. In certain cases, the material may be treated with chemicals, such as a flocculent, to help create the conditions where very fine particles such as clays tend to clump together and separate. In a separate example, in an area of the country with very high rainfall, one might determine to include reinforcing strips and select a different specific material. A third example might be a difference in requirement by a governing body or the critical nature of the installation site. A fourth specification might be to specify a different spacing between the configurable barrier sections. A computer program, selection chart, or other type of engineering specification could be used to help in selection and specific manufacturing recommendations. However the materials are selected and specified, the remainder of this disclosure is similar.
Preferably, the fence panel 12 and the apron panel 14 would be purchased already cut to the correct width and typically be approximately 36 inches and 48 inches wide, respectfully. As described above, the final dimensions could he selected based upon specific needs of the final installation. The width referred to is the height in
The barrier sections 16 would typically be produced by cutting the basic shapes from the raw material. Said cutting device could be a hot knife or other device as referenced earlier. Alternatively the barrier sections 16 could be cut in bulk from a multi-layer stack of raw material using a laser or water jet to cut out the basic shape. Alternatively a roIling die type cutter could be used to stamp out barrier sections 16 one at a time or from a stack of material or a continuously moving single layer of material. Then the edges of each piece could be treated if necessary to prevent fraying. However, the edge or edges that will subsequently be involved in a seam would not necessarily require sealing. If a cut edge is used instead of a fold, then this edge will require sealing to prevent fraying. This sealing could entail folding over an edge and then sewing or bonding with glue and/or heat along said edge lengthwise, or quickly melting the edge with heat.
The fence panel 12 and barrier sections 16 are typically made from material that is relatively elastic. In some cases the fence panel 12 and barrier section 16 material might require the addition of reinforcing strips (not shown). These strips reduce stretching of the material in strategic locations. The reinforcing strips could include a single strip of non-elastic fabric typically less than 1 inch in width and fastened continuously along the top edge of the fence panel or barrier sections. In some situations, additional reinforcing strips can be added to the fence panel 12 at specific heights along the fence. In extreme situations, the fence panel 12 or barrier sections 16 could include a cross hatch of reinforcing strips or threads. These reinforcing strips may be included as part of the original silt fence 10 raw material during its manufacture. This would typically be done as part of the weaving process. Alternatively, this could be added in a subsequent step at a later stage of manufacturing. If added in a subsequent step, the reinforcement strips may be attached by numerous means depending on the physical characteristics of the strips and the fence. Preferably, the reinforcing strips would be sewn on the fence 10 components, but those skilled in the art understand that they could be attached to the material by heat fusion or by gluing. Regardless of the means of attaching the reinforcing strips, their purpose is to add strength to the fence panel or barrier sections when necessary. Differing types of reinforcing strip material or quantity of material could be added depending on the engineering specification of the fence.
Common in the standard silt fence industry is the use of wire as a backing material. An alternative to the cloth type reinforcing strips discussed above, a wire cloth as it is referred to in the industry might be added to the fence panel 10 during manufacturing or added in a subsequent step. The wire cloth could be permanently attached to the fence panel 12 or attached to the fence by gluing or attaching in specific locations. More preferably, if a wire cloth is required it could simply be added as the final silt fence 10 is rolled into a final roll. This will be described in more detail later. If wire is added to the silt fence 10, then that would obviously require modifications to the installation device and manufacturing of the fence.
Manufacturing Steps: To effectively produce the silt fence 10 of the present invention, an efficient process needs to be developed to manufacture the silt fence fabric assembly. The following list highlights the required operational requirements of the finished fabric assembly.
Step 1—Manufacture the FFA: Connecting the apron panel 14 to the fence panel 12 (thus producing a Filter Fence and Apron assembly termed FFA) is typically accomplished by bringing the two materials together on a specific production line to produce a longitudinal seam 200 between the materials as shown in
Large rolls of apron panel material and fence panel material are first installed on feed supply rollers (not shown) adjacent an assembly line. These feed rollers would typically be in close proximity to each other. The roll may be powered to facilitate unrolling and controlling the large and often heavy rolls of raw material. The speed of unrolling may be controlled to produce a specific velocity in say feet per minute. The unroll speed whether powered or un-powered is generally matched between the apron material and fence material. The unroll speed is also generally matched to the speed of the seaming device. This is designed to match the average speed of the FFA assembly line. In the preferred method, a braking device would typically provide proper tension to the material and prevent backlash on the roll. Additionally a material storage loop resembling a “S” shape may be used to maintain tension in the fabric and account for small variation in supply speed. A feedback mechanism may monitor the tension and position of the storage loop to provide feedback and adjust speed of the supply reels and the FFA assembly line speed. Said feedback mechanism could be mechanical or electrical or a combination thereof.
As the two materials are fed into the manufacturing line, the back edge 30 of the apron panel 14 is closely positioned to the seaming location on the fence panel 12. Then the longitudinal seam 200 is produced as described above to produce the FFA assembly shown in
Step 2—Attach the Barrier Sections to the FFA: Referring now to
Attaching the barrier section 16 to the apron side 14 of the FFA and the fence side 12 of the FFA could be accomplished in one operation or each side could be fastened in separate operations. In separate operations, care and possibly an additional step may be required to prevent leaving a small section un-attached where the two seams meet. Typically the spacing of the barrier 16 along the fence panel 12 would be every ten feet. However, these methods could be used to vary barrier 16 spacing distance along the fence panel 12 per engineering specification from the customer or design engineer.
It is preferable that the manufacturing line operates as a continuous process, but the following concepts are also applicable to a discrete process where the line pauses to complete a step before continuing. A discrete process may also allow for better human intervention and labor.
Preferably, the FFA material could be delivered to the manufacturing line on a reel. Typically, as describe in Step 1 above, the FFA would be produced in a separate previous step to the attachment of the barrier sections 16. The preferred method of attachment of the barrier sections 16 to the FFA is by a hot wedge adhesion machine which utilizes a wedged shaped heating device which slightly melts the two surfaces and subsequently bonds them together by pressure. The barrier section 16 would be put in position (
An alternative method for manufacture includes a moving arm which would be positioned to deposit a line of adhesive at the desired attachment line on the FFA. Typically said adhesive would be hot glue that melts and flows while hot, but as it cools it produces a solid bond between the barrier section and the FFA. Though other adhesives could be used as well and may be preferable depending on the materials used. Quickly after deposition of the glue, a mechanical arm with an attachment frame picks up a single pre-cut barrier section or other type barrier sections and positions it over the line of glue on the FFA. In some instances, glue may also be applied to barrier edge. Pressure would be applied to the seam between the barrier section and the FFA until the glue had sufficiently cooled to bond the materials together. With other glues: time, light or some type of catalyst may be necessary to provide bonding.
Supply of the barrier sections 16 individual pieces could be by pre-cut pieces or a mechanical device. The mechanical device may include a system which can unspool a predetermined quantity of material cut to the desired barrier section shape from a bulk roll then supply the cut piece to the assembly area. This would be done before attaching the materials to the FFA.
For the barrier section 16 design of the present invention, one advantage is the material edge may be attached to the FFA assembly and then cut from the bulk spool rather than supplied as precut pieces. In such a case, a mechanical device would unspool barrier material and position it relative to the FFA at the desire attachment location. The edge section of material can then be secured on the attachment line. Adhesion could be by glue or hot wedge or other means. Once the attachment seam is complete, a cutting device would cut the proper amount of material from the barrier section material spool and the process would repeat.
It should be obvious to one skilled in the art, that other types of gluing, sewing, thermal bonding, riveting, and/or stapling or any combination there of can be used to attached the barrier sections 16 to the FFA. It should also be obvious to one skilled in the art that the design of the mechanical device necessary for positioning and fastening the barrier sections could include:
Step 3—Spool the Assembled Silt Fence on Storage Rolls: After the barrier section 16 is attached, the barrier is urged to lay flat against the FFA. Then the fence panel 12 is typically folded on top of the apron panel 14 with the barrier section 16 in-between the fence panel and the apron panel. The end result is a mostly flat assembly as shown in
The finished silt fence 10 assembly must be oriented to have as few folds as possible before it is spooled on the reel. It is important to note that orientation of the seam 200 between the fence panel 12 and the apron panel 14 will have an impact on the spooled thickness. Therefore, care should be taken when deciding how to attach the fence to the apron. One possible orientation for the seam 200 is shown in
By reviewing
Step 4—Finished Salable Rolls of finished Silt Fence for Sale to Customer: The end customer will utilize rolls of silt fence 10 in convenient size packages. Typically said packages would be approximately 1000 to 1500 feet but of a weight to facilitate manual handling of the rolls and to limit the impact of roll weight on the installation machine. Typically the finished roll will utilize a cardboard tube to support and start the roll and maintain an open central tube to facilitate placement onto a support rod on the installation machine. Thus the large storage rolls mentioned previously must be un-rolled and re-rolled into smaller finished rolls ready for installation by the dual vibratory plow.
A critical aspect of this silt fence 10 installation is the required match between direction of travel and the slope of the ground while installing fence using the dual plow installation machine on the jobsite and the un-wind direction of the roll of fence material. Thus there are left hand fence and right hand fence rolls allowing corresponding directions of travel relating to direction of slope. For proper installation two conditions must be met: first, the rolls of fence material must un-wind such that the fence panel 12 is installed on top of the apron panel 14; and second, the fence toe 28 is installed at the desired orientation relative to the jobsite. The orientation of the fence toe 28 for perimeter control generally requires the fence toe be oriented toward the outside of the jobsite or towards the boundary of the jobsite relative to the apron toe 34. In all other situations the fence 10 is to be installed such that the fence toe 28 is generally downstream or downhill for the majority of prevailing water flow on the jobsite. Thus, if one envisions a particular jobsite, for any given direction of installation travel, there is a matching roll of fence material.
Another critical element that must exist on the finished roll, is that regardless of roll direction, when the finished fence 10 is rolled onto the tube, the apron toe 34 and fence toe 28 of the flat assembly must extend beyond the edges of the overlapping fence panel 12 and apron panel 14 to facilitate installation on the jobsite by the dual plow. From a manufacturing standpoint, the large storage rolls as created in step 3 above would typically be loaded on a device for unrolling to allow the fence to be cut into smaller desired lengths and then re-rolled for customer use. These small rolls may carry a marker to indicate proper direction for loading onto the installation machine.
Care in rolling is critical because the folded assembly in the area of the barrier section increases the stack up depth of the silt fence 10 in the middle of the spooled assembly as compared to the edges. This creates the situation where finished and spooled silt fence 10 roll near the edges (the fence toe 28 and the apron toe 34) has less material and thus is much “softer” than the tightly spooled middle portion of the silt fence roll. This may create difficulties with the installation of the silt fence 10 in the field. A solution to this problem is to increase the thickness of the edges of the finished saleable spool. One way to accomplish this is to insert or add a low cost spacer (e.g., a biodegradable paper product) along the edges of the roll during the spooling process. This creates a waste product but is easily disposed of during installation. Alternatively, the paper could be attached near the areas of the fence toe 28 and the apron toe 34 for added thickness. Another method is to create small folds locally near the toe edges such that the folded edge thickness when rolled up is approximately equal to the rolled thickness of the middle section of the finished spooled silt fence 10. One could envision a design of the installation machine that would un-fold portions of the apron toe 34 and fence toe 28 during installation and would require an additional system on the installation device to unfold the edges directly prior to installation.
Cleaning Process: When the silt fence 10 (
Then the silt fence 10 is then cleaned by removing any accumulated silt. One method for cleaning entails using a broom, shovel and wheel barrow (not shown) to dislodge, pickup and transport the accumulated silt. Though this process is effective, it is very labor intensive. A second method would use a specially designed scoop as part of a small front end loader; the process would include traveling mostly perpendicularly to the silt fence with the scoop on top of the apron. The action would scoop up a portion of the accumulated silt as it moves forward, but care must be exercised to not damage the silt fence in the cleaning process. A third approach is to use a vacuum to directly remove the silt. A person by hand or by controlling a vacuum boom would direct the entrance to the vacuum tube near the spoils pile. By moving the vacuum back and forth the spoils would be broken up and then sucked up by the force of the vacuum and moving air. All of these may be effective in certain situations, but each is labor intensive and thus expensive.
A preferred method of cleaning the fence 10 by removing the accumulated silt would utilize a specialty build cleaning machine 210 such as that shown in
The unit 210 shown in
Another alternative would include one or more vacuum entrances located above or in front of the corner brush and conveyor. These would improve cleaning by not allowing the brush to miss or drop spoils as it moves them to the vacuum. Alternatively, a storage bin may be used to replace the vacuum pickup. The bin would travel along the edge of the apron and receive the material from the conveyor brush. As the bin is filled it would be transported to a dump site and then cleaning would resume.
Certain compositions of silt may dry very hard and may not be easily swept or brushed off the silt fence 10. In this situation a specialty designed device which is capable of breaking up the spoils is needed. Specifically a conditioner may consist of pneumatic and/or water jets or a low impact mechanical action such as a rolling grinder/crusher. In case of pneumatic and/or water jets, the jets impinge on the dried soil to dislodge and break up the soil mass to ready it for conveying by the conveyor brush. In the case of the rolling grinder/crusher, this is basically a series of rollers whose edge configuration and movement tends to dislodge and break up the soil mass. But said breakup is low impact to prevent damage to the underlying silt fence material. In some situations, adding vibration to the rollers may improve their action.
Various modifications can be made in the design and operation of the present invention without departing from the spirit thereof. Thus, while the principal preferred construction and methods of manufacture and use of the invention have been explained in what is now considered to represent its best embodiments, it should be understood that the invention may be practiced otherwise than as specifically illustrated and described.
This application claims the benefit of U.S. Provisional Application No. 60/978,999 filed Oct. 10, 2007, the contents of which are incorporated fully herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60978999 | Oct 2007 | US |
