Air Diversion and Dust Control System for Longwall Shearers

1. Field of the Invention

The invention disclosed herein is a ventilation, air diversion, and dust control system for primary use with longwall shearer mining machinery, but can also be applied in situations where air diversion is necessary for the control of contaminants, and other airborne matter.

2. Description of the Prior Art

In longwall mining operations, such as coal mining, dust control and ventilation are critical to maintenance of machine operator safety. During mining operations, dust and harmful gas concentrations are generated, and if uncontrolled, will generally flow into the vicinity of the operator, thus creating a health hazard. Under current methods, removal of airborne matter such as dust and methane gas generated during mining operations is accomplished by either spraying the working area or under more complex procedures, by including in addition to a fluid spray, the inducement of an air flow that diverts the dust and gas away from the areas where it may accumulate. Examples of prior art which spray the working area with a dust suppressing medium are taught in U.S. Pat. No. 4,084,855 (R. C. Miles et al), and U.S. Pat. No. 2,693,950 (A. W. Calder). Examples of prior art which also include induced air flow as an additional means of dust suppression include U.S. Pat. No. 4,157,204 (F. N. Kissell et al) and U.S. Pat. No. 3,333,896 (J. J. Diamanti).

It has been taught that water sprays will induce air flow in the direction of the spray. U.S. Pat. No. 4,157,204 (F. N. Kissell et al) and U.S. patent application Ser. No. 870,162, Jan. 17, 1978, entitled "Ventilation System for Continuous Mining Machines," by F. N. Kissell and R. E. Wallhagen, describe in detail the use of fluid sprays to induce air flows. However, the prior art has concentrated on inducing air flow toward the front of the machine from the rear, across the working face, and then toward the rear on the side away from the operator to dilute the methane gas at the front of the machine. A different problem arises in longwall mining when there is a need to confine the dust cloud rather than forcing air forward to dilute gas. In longwall mining operations, the circular flow pattern characteristic of prior art will not be effective, and simply spraying the working face will not prevent significant amounts of dust from flowing into the area occupied by the machine operators.

The subject invention addresses this problem by providing a system whereby the fresh airstream approaching the machine is split into two separate portions, so that one portion flows to the area occupied by the operator while the other portion is directed by fluid sprays away from the operator, toward the working face and the longwall and thereafter on past the rear of the mining machine. These sprays also increase ventilation by inducing additional air flow across the longwall face as well as suppressing the amount of dust generated during the mining operation.

An air diversion and dust control system for longwall shearer mining machines which consists of support arms, curtain barriers, and a plurality of specifically oriented fluid sprays. The support arms are attached to the front and rear portions of the mining machine and are situated so as to provide horizontal supports level with the top of the mining machine body which project out from the ends of the body on the gob side of the machine. Attached to these support arms and extending downward near the mine floor are passive barrier curtains constructed of suitably stiff material, such that an air flow approaching from the front, or head end, of the machine will be split by the forward barrier curtain, with the rear curtain maintaining the separation of the split air streams. A plurality of fluid sprays are situated on the machine and the forward support arm and are oriented in such a manner as to assist in inducing part of the air stream to flow toward the coal face, on toward the rear, or tail end, of the machine, and finally exiting at the tail end of the machine on the side closest to the longwall face.

It is the object of this invention to split the air flow into two portions, one of which will supply the operators with fresh clean air and the other which will aid in movement of the dust generated during mine operations toward and along the longwall face away from the operators, and then exiting to the rear of the machine.

It is a further object of this invention to provide a means for the suppression of dust generated during mine operations.

It is still an additional object of this invention to provide a means for inducing and controlling air flow by means of a plurality of fluid sprays.

FIG. 1 depicts an isometric drawing of the preferred embodiment of the present invention.

FIG. 2 is a plan view of the preferred embodiment of the present invention.

FIG. 2 is a plan view of a longwall shearer mining machine 1 engaged in the process of mining the coal bed 2. In this illustration, the machine is cutting from left to right, with the cutting action rendered by circular drums 3 and 4 which break the coal and load it onto a conveyor which passes under the body of the machine. As shown in FIGS. 1 and 2, drum 4 cuts the upper part of the coal bed while drum 3 cuts the remaining bench along the floor. The machine operators are located at positions designated by (OP.sub.1) 5 and (OP.sub.2) 6 as shown in FIGS. 1 and 2.

Also shown in the FIG. 2 is the direction of the air stream 7 moving from right to left along the longwall face. It can be seen that cutting drum 4 is upwind of both operators, and that the cloud of dust and gas streaming out in all directions from this drum will envelop the operators at positions 5 and 6.

The purpose of this invention is to provide a simple system by which the dust streaming out from drum 4 is inhibited from moving away from the drum in the direction transverse of the air stream, and to the greatest extent possible moved towards and confined to the freshly cut working face 8.

This is achieved by providing first, a support arm 9 which is extended from the forward corner of the operator's side of the shearer body horizontally, as shown in FIG. 1. A barrier 16 of a heavy flexible material is attached to this arm 9 and extended downward, and possibly upward, from said arm.

Second, a first bank of water sprays 10 is mounted on the top surface of the machine body 1 and support arm 9. These are oriented to spray in a direction downwind and towards the face 8 as indicated in FIG. 2.

Finally, a second bank of sprays is located at 11 and these are generally oriented in a downwind direction.

In experimental work performed to verify the feasibility of this system in performing its dual functions of inducing an air flow in the desired direction and leaching dust from the circulating air, the type of spray nozzle used was Nozzle Type BD20-2, manufactured by Spraying Systems Co., Wheaton, Ill.; however, any water spray nozzle with similar spray characteristics which will induce a sufficient quantity of air will function in this application.

The structural arrangement of the barrier curtain 16 and the spray heads 10 described above performs the objectives of the claimed invention by causing the air stream 7, which is moving from right to left along the working face 8, to be split into two separate streams 12 and 13 as a result of the intervention of the support arm 9 and barrier curtain 16 extending downward from it. The air stream 12 on the side away from the face 8 does not accumulate any dust and passes directly into the breathing zones of the operator(s). The air stream 13 passes between arm 9 and drum 4 accumulating dust which is thrown out by drum 4. Dusty air stream 13 is then induced by the air moving characteristics of sprays 10 to move in the direction of face 8, as indicated in FIG. 2. Sprays 10 and 11 actually cause air stream 13 to increase in velocity. This increased velocity causes the cross section of air stream 13 to decrease, thereby preventing its spreading into the area where the operators are located. Stream 13 moves from right to left along face 8 where it is then diverted around drum 3 by the action of spray bank 11. The continued downwind separation of the clean and dusty air streams 12 and 13, is further enhanced by incorporating a support arm 14, which is extended from the aft corner of the shearer body, as shown in FIG. 1, and barrier curtain 17. It is also possible to futher improve the effectiveness of the system, particularly in severely dusty conditions, by the addition of further air stream directing barriers 15 which may be extended from support arm 14 in a downwind direction 15 to maintain the separation of the clean and dusty air streams, thereby protecting other individuals working downwind of the shearer.