Biodegradable Bag and Method of Use Thereof

Abstract

A method for protection of underwater structures and earthen surfaces. A biodegradable bag is filled with particulate material, such as a cement mixture, and placed underwater so as to protect an underwater structure from damage. The bag has a multi-layer wall, with an outer layer of a biodegradable fabric such as burlap, and an inner layer of a biodegradable material which is permeable to water yet which will not permit very fine solids to pass through the material. A suitable inner layer material is heavy kraft paper. After placement underwater, water penetrates the wall layers and hydrates the cement, eventually forming a firm mass. Another embodiment of the bag comprises a filler tube formed from the bag wall material, which extends into the interior of the bag sufficiently far that escape of the particulate material is minimized during the filling of the bag.

Description

BACKGROUND

There are many pipelines and related underwater structures such as wellheads, valves, etc., which are positioned underwater in rivers, bayous, lakes, bays, and in the open waters of the ocean. Such underwater structures are subject to damage by objects dropped onto them from above, or more commonly from being “hooked” by anchors and the like from vessels overhead. In addition, it is frequently desired to protect underwater earthen surfaces, such as waterbottoms, river and stream banks, shorelines, etc. from erosion and scouring.

In order to protect underwater structures in areas of known potential damage (e.g., in pipeline crossings in areas of high boat traffic), shorelines, etc. prior art apparatus and methods have included placing porous containers, i.e. bags, filled with weighted, particulate fill material, e.g. sand, gravel, or sand/cement mix, atop the pipelines. A number of different configurations of bags have been used, including conventional burlap bags; bags of the size and shape of burlap bags but made of synthetic fibers; and quite elaborate multi-compartment containers, also generally made of porous synthetic material, e.g. polypropylene and the like.

A common drawback of known prior art bags for this application is that the porous nature of the bags permits passage of very fine particulates, such as cement particles or dust through the fabric weave. Health concerns have been raised as a result, because the workers which are handling the cement filled containers are exposed to the dust and various respiratory and other health issues have arisen due to inhalation of the cement dust.

Therefore, there exists an incentive to use a bag for the cement (or other weighted particulate material) which satisfies the dual purpose of being sufficiently porous and permeable that water can penetrate therethrough to the cement inside, which becomes hydrated and hardens into the protective layer; while at the same time is of sufficiently tight weave that it does not permit passage of cement dust or other very fine solid material out of the bag.

Further, there exists an incentive to have a container which fulfills the purposes as set out above, while at the same time is made of bio-degradable materials which permit the cement or other material to be put in place, hydrate and harden, but then biodegrades from the action of the water in which it is immersed. Such materials avoid well known environmental issues arising from the long life of synthetic materials such as polypropylene and the like.

SUMMARY

This invention relates to apparatus and methods used to protect underwater structures and earthen surfaces, including but not limited to waterbottoms and shorelines (above and below the waterline). More particularly, the present invention has particular suitability in protecting pipelines and related structures in underwater settings. One embodiment embodying the principles of the present invention is a strong yet porous bag for containing weighted particulate material, comprising a wall having two layers: an outer layer of strong, open weave and biodegradable fabric, such as burlap, and an inner layer of strong, biodegradable material which permits passage of water but not passage of fine solids, such as heavy kraft paper. The method of the present invention comprises placing such bags in one or more layers over a pipeline or other underwater structure to be protected; or on a waterbottom or along a shoreline or similar water edge to decrease erosion. In addition, the present invention comprises a novel bag structure having a cylindrical valve or filler tube which minimizes escape of very fine particulate matter (dust) during the filling process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a weighting material container (bag) embodying the principles of the present invention, showing the container in an unfolded configuration.

FIG. 2 is a view of the container of FIG. 1, in which the sides of the bag have been folded over and the edges joined, thereby forming the bag.

FIG. 3 is a cross section view along the section line shown in FIG. 2, illustrating a volume of particulate material (such as cement or a cement mixture) inside the bag.

FIG. 3A shows a representative application of the bags.

FIGS. 4-7 show another example of a bag embodying the principles of the present invention, comprising a valve or inlet tube through which the bag is filled.

DETAILED DESCRIPTION

Various embodiments of the present invention will be described in sufficient detail to enable those having ordinary skill in the relevant art field to understand how same is manufactured and used.

A First Embodiment of the Present Invention

FIG. 1 is a view of one embodiment of the weighted particulate container, namely a bag, suitable for use in the present invention, in an unfolded or open configuration. Biodegradable, multi-layer bag 10 has a wall comprising a first layer 20, typically the outer layer, of a strong, porous, biodegradable material such as burlap, although it is understood that other materials can be used as well. The wall of bag 10 further comprises a second layer 30, typically the inner layer, of a biodegradable material that is sufficiently porous and permeable to permit water to pass through it, yet that will not permit small solids particles such as cement dust to pass through. A suitable material for this layer is heavy kraft paper. Therefore, one preferred embodiment of the bag used in the method of the present invention is a bag formed from a two-layer material with a burlap outer layer, with an inner layer of heavy paper bonded thereto. Such bags are presently known and used for holding cement and aggregate mixtures. To applicant's knowledge, such bags are not, however, used in conjunction with applicant's invention, namely placement underwater for protection of underwater structures and earthen surfaces.

It is to be understood, however, that the scope of the invention encompasses use of a multi-layer bag with either material being the inner or outer layer, that is a bag having a burlap inner or outer layer, and a heavy paper inner or outer layer.

Bag 10 further comprises an opening 50 through which the weighted particulate material may be placed into the bag. Opening 50 may be formed by first having a flap 40 of material fastened to one edge of bag 10, as shown in FIG. 1, then when bag 10 is formed by folding over the bag along the centerline, flap 40 is folded down within bag 10 as shown in FIG. 2. The path of fill material is shown in FIG. 2. It is understood that other configurations of opening 50 may be formed in bag 10. FIG. 3 is a cross section of the bag, along the section line shown in FIG. 2 showing a particulate material, such as cement or concrete mixture, therein.

The method of the present invention comprises providing a suitable number of bags 10 filled with a weighted particulate mixture, such as cement/sand mixture; transporting same by vessel to an area in need of protection, such as a pipeline or other underwater structure, or earthen surface such as a waterbottom or shoreline area; and placing the bags in a desired underwater position atop the pipeline or other structure, or on the surface to be protected, by the use of slings, divers, etc. as appropriate. Once in place, it can be appreciated that water will penetrate the layers of bag 10, contact the material inside (namely cement or concrete), and result in a hardened mass, well suited for protection of the underwater structure or earthen surface. Over time, the multiple layers of the bag will biodegrade, leaving the cement behind to continue to serve its protective role. FIG. 3A shows exemplary use of the bags of the present invention for both pipeline protection, and erosion prevention (protection of a bank or shoreline at or around the waterline).

Different types of particulate material, granular and/or powdered solids may be placed inside the bag for protection of underwater structures, waterbottoms, shorelines and the like. As described above, in one presently preferred embodiment cement aggregate is used, which will hydrate and cure into a hardened mass. However, it is possible to insert sand, gravel, soil, pellets of weighting material such as metals, etc. It is therefore to be understood that in its broadest embodiment the invention encompasses any sort of flowable, solid particulate material.

A Second Embodiment of the Present Invention

A second embodiment of the present invention utilizes a novel bag configuration, including its use in underwater placement for protection of underwater structures, such as pipeline protection, and in addition for protection of earthen surfaces such as a shoreline. A key aspect of this embodiment is the cylindrical valve or filler tube 60 which extends into the interior of bag 10. FIGS. 4 and 5 show how filler tube 60 is initially a flat piece fixed to an edge of bag 10, then folded over prior to the body of bag 10 being folded over. As can be seen, filler tube 60 extends outside of bag 10 a sufficient distance to ease the filling process, by way of example approximately one inch. FIG. 6 shows bag 10 after being folded over and the edges fastened together, for example by stitching. As can be seen in FIG. 6, filler tube 60 extends into the interior of bag 10 a sufficient distance to significantly decrease the amount of cement dust and the like which comes back out of bag 10 when being filled. By way of example, filler tube 60 may extend approximately six inches. The flattened diameter of filler tube 60 may be sized as needed for ease in filling, an exemplary dimension being approximately five inches (dimension “D” on FIG. 6). It is to be understood that other methods of forming filler tube 60 and connecting it to bag 10 in a suitable position may be used.

FIG. 7 is a section line as denoted in FIG. 6, showing filler tube 60 in cross section, along with representative fill within bag 10.

As in the description of the bag suitable for use in the previous embodiment (namely, the method of protection of underwater structures), the embodiment of the bag in FIGS. 4-7 advantageously comprises a first layer (either inner or outer layer) of strong, open weave, biodegradable fabric such as burlap, bonded to a second layer (either inner or outer layer) of a biodegradable, water-permeable material, yet one which prevents very small fines and dust (such as cement dust) from passing through, such as a heavy kraft paper.

It is understood that this embodiment can be used in similar fashion to the first embodiment for underwater structure such as pipeline, and shoreline protection, as shown in FIG. 3A.

CONCLUSION

While the foregoing description sets out specificities regarding certain presently preferred embodiments of the invention, it is to be understood that various changes may be made to the described embodiment while remaining within the scope of the invention, and that same are presented only to describe some of the presently preferred embodiments of the invention, and not by way of limitation. Changes can be made to various aspects of the invention, without departing from the scope thereof. For example:

• dimensions of the bag can be altered to suit particular needs
• any sort of underwater structure can be covered and thereby protected, such as pipelines, valves, wellheads, etc.
• earthen surfaces can be covered and thereby protected, for example the bottom of a river or stream to prevent scouring, or a shoreline to prevent erosion due to wave action.

Therefore, the scope of the invention is to be determined not by the illustrative examples set forth above, but by the appended claims and their legal equivalents.

Claims

1. A method of protecting underwater structures, comprising the steps of: providing a biodegradable bag, comprising a wall comprising a first layer of biodegradable fabric bonded to a second layer of biodegradable paper, said paper being permeable to water but not permitting passage of solid particles therethrough;inserting a desired amount of particulate material into said bag; andplacing one or more of said bags in a desired position relative to said underwater structure for protection of same.

2. The method of claim 1, wherein said first layer of biodegradable fabric comprises an open weave burlap on the exterior of said bag, and said second layer of biodegradable paper comprises a kraft paper on the interior of said bag.

3. The method of claim 2, wherein said particulate material comprises cement.

4. The method of claim 3, wherein said particulate material further comprises sand mixed with said cement.

5. A method of protecting an underwater earthen surface, comprising the steps of: providing a biodegradable bag, comprising a wall comprising a first layer of biodegradable fabric bonded to a second layer of biodegradable paper, said paper being permeable to water but not permitting passage of solid particles therethrough;inserting a desired amount of particulate material into said bag; andplacing one or more of said bags in a desired position on said underwater earthen surface, for protection of said underwater earthen surface from erosion.

6. A multi-layer bag for containment of particulate material, comprising: a wall material comprising a first layer of biodegradable fabric and a second layer of biodegradable paper;an elongated filler tube attached to said bag and providing a conduit therein, said filler tube protruding beyond an outer border of said bag and extending into the interior of said bag a sufficient distance to prevent particulate material from escaping said interior of said bag while said bag is being filled, wherein said filler tube is formed from a piece of said wall material.

7. The multi-layer bag of claim 6, wherein said first layer of biodegradable fabric is on the outside of said wall material, and said second layer of biodegradable paper is on the inside of said wall material.

8. The multi-layer bag of claim 7, wherein said filler tube protrudes outside of said bag approximately one inch, and said filler tube protrudes into said interior of said bag approximately six inches.

9. The multi-layer bag of claim 6, wherein said filler tube protrudes outside of said bag approximately one inch, and said filler tube protrudes into said interior of said bag approximately six inches.

10. A method of protecting underwater structures, comprising the steps of: providing a multi-layer bag suitable for containment of particulate material, said multi-layer bag comprising: a wall formed from a wall material comprising a a first layer of biodegradable fabric and a second layer of biodegradable paper;an elongated filler tube attached to said bag and providing a conduit therein, said filler tube protruding beyond an outer border of said bag and extending into the interior of said bag a sufficient distance to prevent particulate material from escaping said interior of said bag while said bag is being filled, wherein said filler tube is formed from a piece of said wall material;inserting a desired amount of particulate material into said bag; andplacing one or more of said bags in a desired position relative to said underwater structure for protection of same.

11. The method of claim 10, wherein said particulate material comprises cement.

12. The method of claim 11, wherein said underwater structure comprises a pipeline.

13. The method of claim 11, wherein said underwater structure comprises a valve assembly.

14. The method of claim 11, wherein said underwater structure comprises a wellhead.

15. A method of protecting an underwater earthen surface subject to erosion by water action, comprising the steps of: providing a multi-layer bag suitable for containment of particulate material, said multi-layer bag comprising: a wall formed from a wall material comprising a a first layer of biodegradable fabric and a second layer of biodegradable paper;an elongated filler tube attached to said bag and providing a conduit therein, said filler tube protruding beyond an outer border of said bag and extending into the interior of said bag a sufficient distance to prevent particulate material from escaping said interior of said bag while said bag is being filled, wherein said filler tube is formed from a piece of said wall material;inserting a desired amount of particulate material into said bag; andplacing one or more of said bags in a desired position on said underwater earthen surface, for protection of said underwater earthen surface from erosion.