Reusable Silt Dam

Abstract

A reusable silt dam having an open frame that defines a generally rectangular prism interior open space, and a series of separate, generally flat, generally rectangular filters arranged side-by-side in the interior, to fill at least most of the interior with filter media.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Provisional patent application Ser. No. 61/296,063, filed on Jan. 19, 2010. The disclosure of this provisional application is incorporated by reference herein.

FIELD

This disclosure relates to a silt dam.

BACKGROUND

Silt dams are commonly required in outdoor construction situations to prevent undesirable silt run-off. Typically, hay bales and sheet plastic silt fences are used. These are expensive, time consuming to put in place and to remove, and the silt fences may not be sufficiently long lasting to be used more than once.

SUMMARY

This disclosure features a reusable device that acts as a silt dam. It dams runoff of groundwater and debris, and then filters the runoff as it passes through the reusable silt dam. The device includes an open frame that carries removable, reusable filtration media. The frame is adapted to be anchored to the ground and/or partially buried in the ground. The frame can carry structure that allows a frame to be coupled to one or more adjacent frames, so that a number of frames can be placed in a line; the coupling is robust but reversible, so that the devices can be decoupled once the silt dam has achieved its purpose.

Featured in an embodiment is a reusable silt dam, comprising an open frame that defines a generally rectangular prism interior open space and a series of separate, generally flat, generally rectangular filters arranged side-by-side in the interior, to fill at least most of the interior with filter media. The frame may comprise a plastic member. The frame may comprise one or more stake-receiving anchoring members, to allow the silt dam to be staked to the ground. The stake-receiving anchoring members may project outwardly from the open frame.

The reusable silt dam may further comprise interlocking features on the frame that allow for temporary releasable interconnection of two adjacent silt dams. The interlocking features may comprise one or more “T”-shaped slots on one end of the frame and one or more “T”-shaped projections on the other end of the frame. The reusable silt dam may further comprise a transition frame that defines a generally triangular or trapezoidal footprint and when connected between two silt dams allows the two silt dams to be located at an angle to one another.

Featured in another embodiment is a silt dam system with a number of generally aligned silt dams, each silt dam comprising an open frame that defines a generally rectangular prism interior open space and has two ends, with interconnection structures on each end that are constructed and arranged to allow the ends of two frames to be temporarily connected and a series of separate, generally flat, generally rectangular filters arranged side-by-side in the interior of each frame, to fill at least most of the frame interiors with filter media. Adjacent silt dams are interconnected via the interconnection structures, to present an essentially continuous line of filters. The silt dam system may further comprise a transition frame that defines a generally triangular or trapezoidal footprint and when connected between two silt dams allows the two silt dams to be located at an angle to one another.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a frame for a reusable silt dam.

FIG. 2 is a top view of the first embodiment of a frame for a reusable silt dam.

FIG. 3 is a close-up partial view of the first embodiment of a frame for a reusable silt dam.

FIGS. 4A and 4B show a vertical post for the first embodiment of a frame for a reusable silt dam.

FIG. 5 is a different view of the vertical post for the first embodiment of a frame for a reusable silt dam.

FIG. 6 is a perspective view of a second embodiment of a frame for a reusable silt dam.

FIGS. 7A and 7B are a detailed view and a cross-sectional view, respectively, of a portion of the second embodiment of a frame for a reusable silt dam.

FIG. 8 is an end view of a reusable silt dam.

FIG. 9 is a perspective view of a third embodiment of a frame for a reusable silt dam, showing a first part of a frame interconnection construction.

FIG. 10 is a perspective view of the third embodiment of a frame for a reusable silt dam, showing the second part of a frame interconnection structure.

FIG. 11 is a top view of another embodiment of a frame for a reusable silt dam.

DETAILED DESCRIPTION

The invention is a reusable silt dam device that can be used as a replacement for both hay bales and silt fences. The reusable silt dam device generally comprises two main parts. A series of reusable filter media is one part. The other part is a structure that can be anchored to the ground or otherwise held in place on the ground and is constructed and arranged to hold the filter media in place such that runoff that may contain silt must pass through the filter media before leaving an area that is bordered by the device. As a result, if the downhill side(s) of an area are lined with a series of the reusable silt dam devices all runoff from the area will pass through the filter media. The silt will thus be removed from the runoff. The structure is designed to allow the filter media to be readily removed from the structure as may be necessary to clean or replace the media.

Several embodiments are shown in the drawings and described herein. A first embodiment is shown in FIGS. 1 through 5. Reusable silt dam 10 comprises an open frame 11 that defines a rectangular prism interior open space 8. Frame 11 in this non-limiting example is made from lower horizontal frame portion 16, upper horizontal frame portion 14, and four vertical rectangular posts 12. Frame 11 can be made in many ways and of many materials. One example is a frame made of ¼″ steel bar stock, two inches wide and bent in the middle at 90 degrees to form “L”-shaped members. These “L”-shaped members can be used for each of the four sides of the top and bottom frame portions, and each of the vertical members. In this embodiment, these are members 32, 33, 46, 47 and 12. Upper and lower transverse members 15 and 17 can be made of flat stock. Another attractive alternative is to make the frame of molded plastic material, either in one piece or in multiple pieces. Using a plastic material such as ABS that is sufficiently rugged to withstand repeated long-term use outdoors can be an attractive lower cost option.

Silt dam 10 preferably also includes at least two series of vertically-aligned stake-receiving anchoring members, to allow the silt dam to be staked to the ground. In this first embodiment, there are two series of stake-receiving anchoring members, one series comprising vertically-aligned members 20 and 22, and the other series comprising vertically-aligned members 24 and 26. These anchoring members are preferably generally annular, in this instance defining rectangular openings, e.g., opening 21 of member 20 and opening 25 of member 24. These openings are preferably 1″ square, to allow 1″ stakes to be driven through the top frame, through the bottom frame, and into the ground. In another embodiment shown in FIGS. 6 and 7, these anchoring members are located on the outside of the frame for reasons explained in more detail below. The anchoring members can take a different shape, can be of a different construction, and can be present in a desired quantity and at desired locations on the frame.

The frame of the silt dam essentially acts to hold in place a series of separate, generally flat, rectangular filters that are arranged side-by-side in the interior of the frame to essentially fill the interior with filter media. Filters 66 are shown in the end view of FIG. 8. Although only four filters are shown for the sake of clarity, in actuality the filters would be stacked or arranged with their generally flat faces touching one another to essentially fill the entire interior 8 of frame 11. The preferred filter material is a non-woven synthetic fiber and high-resistance resin. This material is preferably supplied as sheets about one inch thick and essentially the same size as the interior dimensions of the long rectangular side of the rectangular prism interior space 8 defined by the frame. The material is sufficiently open to allow water to pass through, but acts as a silt dam. The series of about nine different layers of material is effective to prevent silt run-off. Frames of different length and depth can be provided to allow for more or fewer filters 66, and/or filters of different heights or lengths. After the silt dam has been used, filters 66 can be cleaned by rinsing with water or blowing with air, for example. If dam 10 is dry, debris can be dislodged from filters 66 by tapping the filters themselves (or perhaps tapping the entire dam 10) on the ground to dislodge the silt.

One of the frame constructions, using detail shown in FIG. 5, allows the frame to be partially or fully collapsed or disassembled for storage. A partially-collapsing design is shown in FIGS. 3-5. This functionality can be accomplished by fixing vertical post 12 to lower frame portion 16 in a pivoting arrangement, for example using rivets or steel pins. Post 12 can be folded down into the elongated members 46 of the bottom part of the frame portion 16 by curving the bottom side 44 of post 12 so that the post can be folded down in the direction of the arrow “A”, FIG. 5 until it lies down to essentially fit within the contour of member 46. In order to provide for full collapsing, the top of the post can be designed to be removably coupled to upper horizontal frame portion 14. This can be accomplished in any one of several mechanical fashions that would be apparent to one skilled in the field. In this embodiment, this removeable coupling is accomplished by including an enlarged head pin 42 near the top of post 12 that engages in slot 34 in top member 32, FIGS. 3 and 4. Vertical slot extension 36 allows the pin to move up so that the top of post 12 contacts the inside of member 32, so that the weight is carried by post 12 rather than by pin 42. This design allows the four posts to pivot inward as the top is partially collapsed toward the bottom, so that the devices take up less room in storage.

One means of making the frame less rigid so that it can better follow the contour of land in an uneven area is to mold the frame of a material with some flexibility, such as a thermoplastic elastomer. This could eliminate the need for collapsible corners for storage as shown in FIGS. 3 through 5, although the collapsible construction could be maintained in a plastic molded device. Another plastic material that can be used is ABS. Also, the frames can be partially buried to help hold them in place and to help prevent migration of water under the frame. If the frames are partially buried they may not need the anchoring members.

The modification of the stake-receiving anchoring members shown in FIGS. 6 and 7 accomplishes a number of objectives. For one, in the construction shown in FIGS. 1 through 5 with the stakes in the interior of the frame, the stakes may interfere with the filter media. This could lead to voids within the filter area that could result in silt or run-off migrating around the stake and beyond the established site construction run-off control line. By moving the anchoring members (e.g., 52 and 54 that define anchoring stake axis 55) to the outside of the open frame, the stakes do not interfere with the filter media. Having the anchoring members at the back of open frame 11 a also allows the stakes to take up any force associated with water moving up against the frames and filter media. Further, these stake-receiving anchoring members can be arranged to allow the stakes to be driven through them at a slight angle (for example, at about a five degree angle) to help create some downward pressure that helps to keep the silt dam front that faces the construction site seated on the ground. This arrangement can be accomplished by making the bottom anchoring member about ⅝″ longer than the top anchoring member, and making the interior walls 58 and 60 (that help define stake-receiving opening 61) at the desired angle (five degrees) so that the stakes are guided at the proper angle.

An additional modification is to incorporate a construction that allows adjacent silt dams to be interlocked where they meet end-to-end. This can be accomplished with a male feature at one end of each frame and a complementary female feature at the other end of each frame. The mating could be accomplished by dropping one end into the end of an adjacent frame, or by sliding engagement between the ends of adjacent frames. One non-limiting embodiment that accomplishes this modification is shown in FIGS. 9 and 10. End 92 of frame 11b carries “T”-shaped slots 84 and 86. The other end 90 is modified to define mating “T”-shaped projections 82 and 83. Both the projections and the slots preferably run from the top to about 1.25″ from the bottom so as not to interfere with the structural integrity of the corners of the frame. It is expected that slots about 0.25″ deep and about 3/16″ wide will be sufficient to accomplish the interconnection, although these dimensions are not a limitation of the design. Other means of releasably interconnecting adjacent devices can be used instead, such as other tab and slot or other male/female interlocking arrangements.

In order to accommodate runs of the inventive silt dams that need to deviate from a straight line, the inventive silt damming system can include transition frames that will help to make corners when laying out the silt dams. An embodiment of these transition frames is generally triangular in shape and has the same height and depth and interlocking features as the silt dam described above. The transition frame preferably spans 22.5 degrees. The male and female interlocking features are reversed on two separate triangular frames to allow the silt dam to turn left or right at 22.5 degrees. To make a 45 degree turn two transition frames are interconnected. Or, if a transition frame spans 45 degrees then only one needs to be used. An example frame 100 is shown in FIG. 11 and generally defines an isosceles trapezoid. Filter media for frame 100 would need to be of variable length as the distance between sides 101 and 102 is variable.

Various dimensions of certain embodiments may help to illustrate features, but are not limiting as to the scope of the disclosure. In one example, frame 11 is about 14 inches high, 9 inches deep and 32 inches wide. Cross members 15 and 17 are spaced about 10 inches from the ends of frame 11. Slot 34 is about 12 inches long. The end of slot 34 where extension 36 is located is about 9/16 inches from the end of member 32. The anchoring members are located about 8 inches from the ends of frame 11. Anchoring member 54 is about 4¼ inches square. Stake-receiving opening 61 is about 2¼ inches square.

Other embodiments will occur to those skilled in the art and are within the scope of the claims.

Claims

1. A reusable silt dam, comprising:

an open frame that defines a generally rectangular prism interior open space; and

a series of separate, generally flat, generally rectangular filters arranged side-by-side in the interior, to fill at least most of the interior with filter media.

2. The reusable silt dam of claim 1 in which the frame comprises a plastic member.

3. The reusable silt dam of claim 1 in which the frame comprises one or more stake-receiving anchoring members, to allow the silt dam to be staked to the ground.

4. The reusable silt dam of claim 3 in which the stake-receiving anchoring members project outwardly from the open frame.

5. The reusable silt dam of claim 1 further comprising interlocking features on the frame that allow for temporary releasable interconnection of two adjacent silt dams.

6. The reusable silt dam of claim 5 in which the interlocking features comprise one or more “T”-shaped slots on one end of the frame and one or more “T”-shaped projections on the other end of the frame.

7. The reusable silt dam of claim 1 further comprising a transition frame that defines a generally triangular or trapezoidal footprint and when connected between two silt dams allows the two silt dams to be located at an angle to one another.

8. A silt dam system, comprising:

a plurality of generally aligned silt dams, each silt dam comprising: an open frame that defines a generally rectangular prism interior open space and has two ends, with interconnection structures on each end that are constructed and arranged to allow the ends of two frames to be temporarily connected; and a series of separate, generally flat, generally rectangular filters arranged side-by-side in the interior of each frame, to fill at least most of the frame interiors with filter media;

wherein adjacent silt dams are interconnected via the interconnection structures, to present an essentially continuous line of filters.

9. The silt dam system of claim 8 further comprising a transition frame that defines a generally triangular or trapezoidal footprint and when connected between two silt dams allows the two silt dams to be located at an angle to one another.