Hydraulic and earth engineering – Subterranean waste disposal – containment – or treatment – Waste barrier – containment – or monitoring
Reexamination Certificate
1999-02-11
2001-07-24
Bagnell, David (Department: 3673)
Hydraulic and earth engineering
Subterranean waste disposal, containment, or treatment
Waste barrier, containment, or monitoring
C405S270000
Reexamination Certificate
active
06264400
ABSTRACT:
FIELD OF THE INVENTION
This invention is concerned with dispensers, and relates in particular to tractor-drawn dispensers suitable for use with rolls of sheet material such as that GCL sheeting used in the lining or capping of tips, reservoirs, contaminated land and the like.
BACKGROUND
The disposal of rubbish (trash, garbage), and other waste materials, is a problem that has concerned mankind for centuries, and that worsens with each year as populations and the sheer amount of waste increase. It has long been the practice to transport all rubbish to, and dump it at, some central site, and at the present time there are, adjacent most large towns, such dumps—or “tips”—specially designated for this purpose.
In earlier years a tip was merely an open area of ground onto which waste could be deposited, or at the very most a natural depression that could be filled up with the refuse. Later, though, much use was made of artificial pits such as result from the excavation of sand, gravel, clay, and other natural raw materials, while these days it is often necessary to construct a pit specifically for the purpose. And as dumps evolve, so the rules and regulations governing their use become more strict and more complex, in an effort to prevent their causing more problems than they solve. Specifically, it has become a regulatory requirement that every refuse pit be so constructed that none of its contents—and none of any materials that might arise from its contents—can in any way affect the ambient conditions. In particular, every pit must be so lined that nothing can seep down, into the underlying ground, and so pollute the surroundings—and especially the local water table and supply. Moreover, once the pit is full, and before earth can be laid on top and the whole landscaped, it is necessary to seal off the top as well.
A modern pit, which can vary in size from 25,000 sq.m (2.5 hectares, or about 6.25 acre) for a small pit up to 80,000 sq.m (8 ha, or about 20 acre) and beyond for a larger one—the latter are usually made up of a number of smaller pits, or “cells”—must be constructed to a set of very tight rules, and so far as leakage or seepage are concerned these relate to how the pit is lined.
Without going into too much detail, an earth pit must first have a compacted surface on top of which is a compacted sand layer with a flat and smooth surface (with no projections or indentations more that an inch—25 mm—high or deep). Then, on top of the sand, there must be laid an impervious lining layer—such as that known as a geosynthetic clay liner, or GCL. Such a liner is, in essence, a sandwich of bentonite clay between two layers of heavy-duty synthetic resin fabric (which may be either in film or in woven form). Typical examples of such liners are those made by Colloid Environmental Technologies Co. (CETCO), of Illinois, and available under the registered trademarks BENTOMAT and CLAYMAX, which cost around $5.00 per square meter. They come in rolls, each of which is a ribbon-like sheet of material (known, when deployed, as a “panel”) from 3.5-5 m (12-16.5 ft) wide, from 40-45 m (135-150 ft) long, and about 10-11 mm (0.4-0.45 in) thick, and weighs, depending on the material, anywhere from 1000-1450 kg (about 2,200-3,200 lb, or about a ton to a ton and a half). These are laid directly onto the ground formation surface with an overlap—normally of around 15-22.5 mm (6-9 in), but in any case as required by the local authorities. Ignoring the overlap, it can be seen that the cost in materials alone of lining a large pit will be over $400,000.00, with another $400,000.00 or so for subsequently capping it—sealing it off once it's full. Getting the overlap right so that it is large enough to form a satisfactory seal but not so large as to waste significant amounts of material can save quite a lot of money.
The laying is commonly accomplished by the simple but effective means of threading the roll onto a support rod, attaching the rod by chains at each end to a rigid beam, mounting the beam (again with chains) to the bucket of a JCB—or a tracked
360
excavator, which is preferred if the ground is not to be churned up—and then carrying the roll along, letting the sheet liner pay out.
Unfortunately this method, though uncomplicated, is not especially accurate. Under windy conditions the unrolling liner can billow back and forth. Additionally, the chains that support the roll on the beam, and the beam on the bucket, allow the roll to swing from side to side, and it is all too easy to lay the liner such that the overlap is either too large or too small (so that there may even be a gap). Moreover, unless the roll is somehow braked, it can easily spin off excess material to form a heap.
SUMMARY OF THE INVENTION
The present invention seeks to solve these problems by providing a novel form of dispenser apparatus that can be “rigidly” attached to a tractor's (conventional) three-point mounting—a single, upper, pivot mounting that can be raised or lowered by the tractor's normal hydraulic system so as similarly to raise or lower whatever the mounting is carrying, and a pair of laterally-separated lower “floating” rigid link arms pivotally attached at their inboard ends to the tractor for slight sideways movement—and that can, optionally, be associated with “steering” means by which the roll can be shifted laterally from side to side so as to enable some small adjustment of the liner's laying position, and thus of the overlap between the sheet being laid and one previously laid.
More specifically, the invention proposes a long beam, or framework of beams, having roughly centrally thereof a three-point mounting by which it can be attached behind a tractor clear of the ground, the beam having normally-disposed end plates between which there may be borne a support rod carrying a roll of liner material. In the preferred case the beam is associated with positioning control means that can be used to adjust the lateral angle of the lower three-point mounting linkages, and so move the roll to either side to modify where the liner is laid.
In one aspect, therefore, this invention provides a tractor-mountable dispenser for a roll of material such as a geosynthetic clay liner, the dispenser comprising an elongate beam, or framework of beams, having roughly centrally thereof a three-point mounting by which it can be attached to the tractor so as to extend laterally therebehind, the beam carrying at either end a plate having rod-mounting means such that there may in use be borne between the end plates a support rod carrying the roll of material.
It is particularly preferred if the beam be associated with positioning control means that in operation can be used to effect adjustment of the lateral angle of the lower linkages of the three-point mounting, and thus move the roll to one side or the other to modify where, in use, the liner is laid.
Although for the most part herein the invention is discussed in relation to the lining or capping of a tip for trash, refuse and the like, it may in fact also be of use in the lining of other container-like holes in the ground. For example, modern water reservoirs need to be lined to stop their contents from leaking away, and the dispenser of the invention can be used to lay such a lining. Again, in some countries it may be desirable to store crude oil in giant pits, or perhaps to place surface storage tanks in safety pits to contain any leakage, and obviously it is extremely important to ensure that the pits are sufficiently well lined and/or capped to prevent oil from seeping into the surroundings.
The invention provides a tractor-mountable dispenser. The tractor employed to carry the dispenser may be of any type—a suitably-shod conventional agricultural tractor or loading shovel, for example, or a tracked crawler of some sort—provided, of course, that it has a suitable three-point mounting. As noted above, such a conventional three-point mounting comprises a single, upper, pivot mounting with an adjustable-length link and a pair of laterally-separated lower rigid
Bagnell David
Elman & Associates
Singh Sunil
LandOfFree
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