Mandrel-wound flocculant-containing fiber filtration tubes

Abstract

Fiber filtration tubes containing flocculant are produced by winding a preformed mat of natural fibers about a mandrel. The tubes may be joined end to end to produce products of significant length, and are highly suitable in removing even very fine sediment during use in erosion control.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention pertains to fiber filtration tubes for use in erosion and sediment control. [0003] 2. Background Art [0004] Fiber mulch mats are in widespread use in preventing soil erosion and to aid in germination of seed beds. The fibers in such mats, also termed turf reinforcement mats (“TRM”) may be derived from numerous organic sources, including wood fibers, straw, jute, sisal, coconut, and paper. Due to its ready availability, wood fibers are preferred for such products. [0005] Fiber mulch mats must possess satisfactory physical characteristics which are often conflicting. For example, the mats should aid in water retention when used to aid seed germination, yet must be open enough to allow seedlings to penetrate the mat. The mats must also be of sufficient strength to be handled effectively during installation over soil and / or seedbeds, and must retain their integrity over extended periods while expos...

AI Technical Summary

Benefits of technology

The present invention is about a process for making fiber filtration tubes. These tubes are made by winding a mat of natural fibers around a mandrel, either a non-removable or removable one. The fiber filtration tube also contains a flocculating agent to help remove fine particles. This process results in a high degree of sediment control for all sediment sizes. The longer fiber filtration tubes are made by adhesive bonding shorter ones. Overall, this invention provides a more efficient and economical way to make fiber filtration tubes with improved sediment control.

Problems solved by technology

Otherwise, their ability to control run-off, and hence erosion, would be rapidly lost.

Such natural or chemically modified natural binders suffer from the defect of rapid degradation due to exposure and to the action of microorganisms.

Such polymer-based binders are generally more expensive than natural binders, and many exhibit at least modest water swellability, which decreases the binding capability and hence strength of the product over time following installation.

No preformed mats are disclosed, however, and the degree of entanglement of either natural or synthetic fibers, without the use of a binder, may not be sufficient to formulate a mat with adequate tear strength or tensile strength.

However, erosion control mats do not always work well alone on steep slopes, and are generally impractical to install over large areas.

Finally, while the erosion control mats previously described can be effective to reduce water velocity and trap larger sediment to a degree, they are largely ineffective at trapping very fine particulates such as colloidal clay particles.

When employed to trap fine sediment, such fiber rolls may also be termed “filtration tubes.” However, tubes specifically designed to trap and flocculate fine sediment have not been commercially available; what “filtration” occurs has been incidental to commercial wattles or fiber rolls whose principle purpose is preventing washout, lowering the velocity of water runoff, and trapping large sediment particles.

A disadvantage of conventional fiber rolls or wattles is their relatively high transportation cost, as their density is rather low, and as they can tolerate little compression to facilitate shipping.

A further disadvantage is their limited lifespan.

The natural fibers tend to degrade rather quickly, in most cases within a year or two.

However, the tradeoff is that such higher packing density both lowers the water filtration rate, which results in overflow under high rainfall conditions and may also causes the tubes to become plugged with sediment particles, losing much of their effectiveness, again resulting in overflow.

Conventional straw fiber rolls also do not absorb water easily due to the high lignin content and shape of the rice straw fibers as well as the limited surface area per unit weight of such products.

Washout of newly installed straw and wood excelsior fiber rolls can occur due to their light weight and inability to absorb large amounts of water.

Colloidal particles, in general are very inefficiently trapped by all such products.

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