|Title of Invention||
A DEVICE FOR COLLECTION OF DUST FROM JACK HAMMER DRILLING
|Abstract||The present invention relates to a device for collection of dust from Jack Hammer drilling, which comprises of a hood open at both ends wherein the bottom side is wider and the top side tapered, both ends of the said hood being provided with flanges at the top and at the bottom, the top flange being provided with an elastic collared washer held together between two discs and attached to the top flange by known means ; the bottom flange is attached to a collared disc with a cushion base; the said bottom flange is provided with a foot pedal which is attached to the flange and disc by known means ; the said hood has an extended opening to its side, the said extended end being provided with a clamp by which a filter bag is attached to the extended end and the filter bag is tied to its distal end by rope .|
|Full Text||This invention relates to a Device for collection of dust from Jack Hammer Drilling
This invention relates to a device for collection of
dust formed during Jack hammer drilling in rocks in open
Presently, in opencast mines large size rock boulders
are formed after primary blasting with high explosives.
These boulders are further broken down by secondary
blasting. For secondary blasting shot holes are
drilled on boulders by Jack Hammer drills.
In smaller capacity opencast mines, jack hammer
drilling is regularly carried out in the primary stage
In underground metal mines, horizontal holes are
drilled into ore face with Jack hammer drills
During such Jack Hammer drilling in rocks, rock is
crushed to dust of various size fractions. The drill hole is
cleaned with a certain quantity of compressed air which lifts
the rock cuttings to surface and pollutes the atmosphere. In
otherwords, the energy available in the compressed air which is
otherwise uses to improve rate of drilling is wasted in
polluting the work atmosphere.
Rock dust invariably contains free silica which is injurious to workers' lung and leads to an irreversible diseased condition, i.e., Silicosis, Silicosis leads to lung impairment and leads to premature death. Normally a gang of 2-3 workers are associated with Jack Hammer drilling with each machine. The drill rods are small, below one meter in length, and therefore, the drillers are directly exposed to freshly generated rock dust. The drillers drill about 30-50 holes per shift.
A dust control device, therefore is necessary not only to reduce atmospheric pollution, but to protect workers from Silicosis, as well.
At present no dust control device is used in mines during Jack Hammer drilling in rocks. Director General, of Mines Safety stipulates use of water, compressed air operated extraction for dust, or any other method for reducing pollution at work place. However neither water or any extraction system is currently used because of certain inherent demerits in them. Even though water requirement for dust suppression during drilling is low, water is not easily available especially in distant mine workings. Water in drill holes leads to jamming of drill in drill holes, which, while reducing rate of drilling
increases the energy requirement, and therefore cost
Besides, drill bit gets repeatedly churned over wet dust at the bottom of drill hole, thus adversely
affecting wear and tear of drill bit and rate of drilling.
Above all water has very low efficiency for capture of respirable dust which is a major part of drill dust.
For these reasons, use of water does not find favour in dust control during Jack Hammer drilling.
Compressed air operated dust extractor requires use of a cumbersome hood, ejection nozzles and compressed air pipe lines. These are heavy and unwieldy., - This dust extractor, when in use, allows a certain
quantity of compressed air to pass through an ejector nozzle, and in the process extract fine dust which is thrown in the atmosphere.
The coarse dust is left close to the drill hole, and the dust falls back into drill hole affecting drillincj rate, and adds to pollution load.
Above all, a part of the compressed air energy whoich is therwise available for drilling is utilised for dust collection, which means it adds to cost of drilling.
For these reasons the compressed air operated dust extraction device too does not find favour in pollution control during Jack hammer drilling.
Therefore, a device which works without use of any source of energy, yet gives a very high degree of dust control is necessary for pollution abatement resulting from drilling with Jack Hammer. The new device is designed with this objective.
The device for collection of dust from Jack Hammer drilling is described as hereinunder with reference to the figure 1 and figure 2 of the drawings accompanying to this specification. Figure 1 shows the assembled main body of the device and figure 2 the filter bag.
Accordingly, the present invention provides a device for collection of dust from Jack Hammer drilling, which comprises of a hood (1) open at both ends where in the bottom side is wider and the top side tapered, both ends of the said
hood being provided with flanges (11) at the top and (12) at the bottom, the top flange being provided with an elastic col lared washer (3) held together between two discs (2) and at-tached to the top flange (11) by known means (4); the bottom flange (12) is attached to a collared disc (7) with a cushion (8) base; the said bottom flange (12) is provided with a foot pedal (9) which is attached to the flange (12) and disc (7) by known means (4A); the said hood (1) has an extended opening (13) to its side, the said extended end (13) being provided with a clamp (5) by which a filter bag (6) is attached to the extended end (13) and the filter bag is tied to its distal end by rope (10).
The fully assembled hood and filter bag form the dust collector device for collection of dust during jack hammer drilling.
The main functions of the parts of the device for collection of dust generating from compressed air operated Jack Hammer drilling in rocks, that works without any source of energy are a hood (1) for containing rock cuttings from drill-ing, a filter bag (6) for channelising and filtering the dusty air, a cushioned collared (7) base to prevent fall back of rock cuttings to drill hole and also to prevent leakage of dusty air from base, and an elastic washer (3) which allows drill rod to
move up and down, without allowing the dusty air to pass through the contact area between rod and washer to outside.
A speciality with Jack Hammer drilling is that during drilling the drill rod continuously move up and down, while it rotates. The elastic collared washer (3) is designed such that it can move up and down with the drill rod during drilling, while it holds the drill rod fast, and yet it allows free movement of drill rod - i.e., easy up and down movement through it as and when necessary. This is achieved by the elastic character of the wahser. As a result of this, the compressed air that brings out cuttings from drill hole in the normal process of drilling is not allowed to escape through drill rod side. The cushion base of the device does not allow compressed air with the cuttings to escape from the base side. The only way for the air to pass through is through the filter bag with its large surface area and millions of fine pores. The large surface area of bag permits slow filtration without back pres-sure. While the fine cuttings reach the bag, the coarse ones gets deposited inside the hood around the base collar, and thus it is prevented from falling back to drill hole.
Working operation of the device
The fully assembled device with the hood (1), filter-bag (6) and elastic collared washer (3) is placed on its cush-ion base (8) at the site where drilling is to be carried out.
The filter bag is clamped (5) to the extended opening (13) and stratched. The distal end of the filter bag is tied by rope (10). The Jack Hammer drill rod is Introduced through the elastic collared washer (3) and through the bottom collar (7) till the drill bit touched the rock strata to be drilled. The device is held to the rock by the foot pedal. It is now ready for drilling. Once the drilling started, the rock cutting is brought out from the drill hole, and channelised through the filter bag. The filter bag allows the fine dust to be re-tained, while litting the air go out through its pores. The slow rate of filtration through large surface area of the filter bag allows for smooth drilling with least back pressure.
The main advantages of the new invention are;
The device does not use any source of energy for dust
The device collects almost/more than 99% of dust from
jack hammer drilling.
The device does not allow respirable dust to escape out
to general atmosphere.
The device is light weight, portable and easy to use.
It does not use water, therefore no jamming.
Drill cuttings do not fall back in to drill hole, hence no
wear and tear.
And it does not add to the cost of drilling, nor it
reguires any extra hand for operation.
A device for collection of dust from Jack Hammer drill-ing, which comprises of a hood (1) open at both ends wherein the bottom side Is wider and the top side tapered, both ends of the said hood being provided with flanges (11) at the top and (12) at the bottom, the top flange being provided with an elastic collared washer (3) held together between two discs (2) and attached to the top flange (11) by known means (4); the bottom flange (12) is attached to a collared disc (7) with a. cushion (8) base; the said bottom flange (12) is provided with a foot pedal (9) which is attached to the flange (12) and disc (7) by known means (4A); the said hood (1) has an extended opening (13) to its side, the said extended end (13) being provided with a clamp (5) by which a filter bag (6) is attached to the extended end (13) and the filter bag is tied to its distal end by rope (10).
2. A device for collection of dust from jack hammer drilling substantially as herein described with reference to the drawings accompanying this specification.
|Indian Patent Application Number||1103/DEL/1998|
|PG Journal Number||10/2008|
|Date of Filing||27-Apr-1998|
|Name of Patentee||COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH|
|Applicant Address||RAFI MARG, NEW DELHI 110001, INDIA|
|PCT International Classification Number||B23Q|
|PCT International Application Number||N/A|
|PCT International Filing date|