US3205953A

US3205953A - Apparatus for thermal drilling

Info

Publication number: US3205953A
Application number: US301256A
Authority: US
Inventors: Francis G Ferrabee
Original assignee: Canadian Ingersoll Rand Co Ltd
Current assignee: Canadian Ingersoll Rand Co Ltd
Priority date: 1963-08-12
Filing date: 1963-08-12
Publication date: 1965-09-14
Anticipated expiration: 1982-09-14
Also published as: BE651480A; GB1042817A

Description

Sept. 14, 1965 F. G. FERRABEE 3,205,953

APPARATUS FOR THERMAL DRILLING 4 Sheets-Sheet 1 Filed Aug. 12, 1965 FROM FUEL FROM OXYGEN PUMP SUPPLY I30 INVENTOR. FRANGS 61 FERRABEE BY l I A ATTORNEY p 14, 1955 F. G. FERRABEE 3,205,953

APPARATUS FOR THERMAL DRILLING Filed Aug. 12, 1965 4 Sheets-Sheet 2 I me INVENTOR. F A ERRABEE F/G. 2 Z 6 ATTORNEY Se t. 14, 1965 F. e. FERRABEE APPARATUS FOR THERMAL DRILLING 4 Sheets-Sheet 5 Filed Aug. 12, 1963 FROM OXYGEN SUPPLY FROM FUEL PUMP INVENTOR.

: FRANCIS G. FERRABEE ATTORNEY FIG. 3

Se t. 14, 1965 F. c. FERRABEE 3,205,953

APPARATUS FOR THERMAL DRILLING Filed Aug. 12, 1965 4 Sheets-Sheet 4 FIG. 4

ATTORNEY United States Patent C) 3,205,953 APPARATUS FOR THERMAL DRILLING Francis G. Ferrahee, St. Bruno, Quebec, Qanada, assignor to (Ianadian lngersoll-Rand Company, Ltd, Montreal, Quebec, Canada, a corporation of Canada Filed Aug. 12, 1963, Ser. No. 301,256 11 Ciaims. (Ci. 17514) The present invention relates to rock drills and more particularly to an improved rock drill and to an improved method of breaking rocks.

In the art of mining, one of the problems encountered has always been the breaking of rocks. Currently, and for some seventy years or more, the best method of breaking rock comprised drilling a series of holes in the rocks and loading the drilled holes with explosive, prior to shooting or exploding the series of holes.

Some holes, for blasting, are made with conventional rotary drills, which cuts a core of the material, and some by conventional percussion drills, which reduces the rocks, in the area being drilled, to line cuttings which are blown or washed out of the drilled holes as drilling progresses. These techniques are in general use.

Lately, attempts have been made to employ heat to melt the rocks, in the area where the hole is Wanted, and flow the molten material back to the starting point of the hole. This technique is partially successful.

Attempts have been made to combine rotary and percussion drilling in order to speed up the process of rotary drilling and to increase the bore of the holes drilled by percussion. Some success has been achieved with this combination.

U.S. Patent No. 2,628,817 issued to R. O. Wyland, J r. on February 17, 1953 recites a method for piercing a hole by use of a burner nozzle.

U.S. Patent No. Re. 22,964, issued to C. I. Burch on January 20, 1948 recites a method for piercing holes by melting rock formations under the action of intense localized heat.

The methods of thermal piercing recited in the U.S. patents enumerated above have not been successful commercially for piercing blast holes of sutlicient depth and smoothness to meet the requirements of mines and quarnes.

Other methods of piercing holes in rock formations such as the use of pneumaticdrills, saws, or chisels, are often aided by explosives, such as dynamite. Such mechanical operations are slow and, in the case of penumatic drilling for blasting holes in particular, require an investment in a large number of drill bits requiring frequent resharpening or replacement. Moreover, the greater the hardness and abrasiveness of the material to be worked, the slower is the rate of mechanical working and the greater the cost.

It is the general object of the present invention to avoid and overcome the foregoing and other difiiculties of and objections to the prior art practices by the provision of a rock drill that will provide holes in rock formations easily and quickly.

Another object of the present invention is to provide a rock drill utilizing heat applied over a rock formation surface to allow easy spalling or shattering of the preheated rock formation by the later application of fairly light percussion blows to the rock formation.

Still another object of the present invention is to provide a faster and more economic method of drilling holes in rock formations.

The aforesaid objects of the present invention, and other objects which will become apparent as the description proceeds, are achieved by providing an improved rock drill, for providing holes in rock formations, the

Cir

messes Patented Sept. 14, 1965 rock drill having a driven drilling member and heating means operatively associated with the drilling member for preheating rocks thus facilitating the drilling of such rocks. The driven member can be rotary driven, reciprocatory driven, or both. In addition impact means is disposed in the casing and is slidably associated with the first rotation transmitting means for delivering percussive blows to the tool holding means. The objects of the present invention are further achieved by providing a method for piercing holes in rock formations comprising the steps of heating the rock formations, drilling the rock formations with a drill bit and delivering percussive blows to the drill bit.

For a better understanding of the present invention reference should be had to the accompanying drawings, wherein like numerals of reference indicate similar parts throughout the several views and wherein:

FIGURE 1 is a longitudinal sectional view of the rock drill, illustrating the position of the piston in its forwardmost position;

FIGURE 1A is a continuation of the longitudinal sectional view of the rock drill continued from line 1A lA of FIGURE 1 in the direction of the arrows;

FIGURE 2 is an enlarged sectional view of the drill bit of FIGURE 1A showing in detail the internal combustion chamber in the drill bit;

FIGURE 3 is a detailed sectional view of the upper portion of FIGURE 1;

FIGURE 4 is a sectional view along the line 44 of FIGURE 1 in the direction of the arrows;

FIGURE 5 is a sectional view along the line 55 of FIGURE 1 in the direction of the arrows, and showing a gear assembly;

FIGURE 6 is a sectional view along the line 6-6 of FIGURE 1, in the direction of the arrows, and showing kicker ports;

FIGURE 7 is a fragmentary longitudinal view of a portion of FIGURE 1 illustrating the position of the piston in the rearrnost position;

FIGURE 8 is a fragmentary sectional view partially in longitudinal section of the left side of FIGURE 1 showing a spool type valve in its rearnost position:

FIGURE 9 is a sectional view of a drill bit illustrating another alternative embodiment of the invention;

Although the principles of the present invention are broadly applicable to all drilling apparatus and rock drills of the rotary and percussive type, the present invention is particularly adapted for use in conjunction with rock drills of the centrally driven independent rotation type, and hence it has been so illustrated and will be so described.

Referring to FIGURES 1 and 1A a conventional rock drill 22 of the centrally driven independent rotation type, as disclosed in U.S. patent application Serial No. 197,655, filed on May 25, 1962, by Paul A. Lincoln, has a casing 20. A first rotation transmitting means, such as a hollow torque. shaft 24, is disposed axially in the drill casing 20 and extends from the back end 26 of the rock drill 22 to the tool or front end 28 of rock drill 22. The front portion of the torque shaft 24 is splined at 30 (FIG- URE 1A) to engage a splined counterbored portion 32 in the rear end of a drilling member, such as a tool holding means (i.e. a drill steel 34 disposed on the drill casing 20 in the tool end 28) and a drill bit 152. Such spline connection 30 is utilized for transmitting rotation to the drill steel 34 by rotary drive means, such as an air motor 36 (FIGURE 1).

Drive means The rotary air motor 36, as best shown in FIGURES 1 and 4 is disposed in the back end or head 26 of the rock drill 22 and is provided with a rotor shaft 38 which is drivingly connected to the torque shaft 24 and in turn is supported for rotation in bearings 48 and 42 (FIG. 1). The

bearings

40 and 42 are disposed in supporting

walls

44 and 46 of the back end 26 of the rock drill 22. Since the air motor 36 is located adjacent to the torque shaft 24 and also has a far greater rotation in r.p.m. than the desired rotational speed of the drill steel 34, a second rotation transmitting means, such as a gear assembly (comprising an eccentric 48, internal oscillating gear 50, and driven gear 52 (FIGS. 1 and is provided to accomplish the dual purpose of transmitting rotation from the air motor 36 to the torque shaft 24 (to attain central rotation drive) and of reducing the rotation speed required to properly drive the drill steel 34.

To provide the central rotation drive, at reduced speed, of the torque shaft 24, the air motor 36 rotatably drives the internal oscillating gear 58 through the eccentric 48 on the rotor shaft 38; the internal oscillating gear 58 in turn driving the driven gear 52. The driven gear 52 in turn transmits rotation to the torque shaft 24 through spline 56. Therefore, it can be seen that axial rotation of the drill steel 34 is achieved by the above described drive means.

Inasmuch as the rotational speed of the air motor 36 is far greater than the desired rotational speed of the drill steel 34, the r.p.m. generated by the air motor 36 must be reduced before it is delivered to the drill steel 34. The required speed reduction is accomplished by providing the eccentric 48 at the forward end 58 of rotor shaft 38 (FIG. 1) disposed within an axial bore in the internal gear 50. The external gear 52 surrounds gear 58 and is spline connected at 56 to the torque shaft 24 to accomplish the transmittal of rotation from air motor 36 to the torque shaft 24. A pin 60 (FIGS. 1 and 5), having one end retained in casing wall 46 (FIG. 1), extends into a hole 62 in internal gear 58 (FIG. 1). Pin 60 serves to prevent rotation of internal gear 50 so that, as eccentric 48 rotates, internal gear 50 is oscillated into engagement with the teeth of external gear 52. Sufiicient clearance is allowed pin 68 in wall 46 to permit the internal gear 50 to follow the eccentric 48.

For each revolution of eccentric 48, the external gear 52 is rotated two teeth. It can be seen that if the internal gear 50 and the external gear 52 are provided with 34 and 36 teeth respectively, a speed reduction of 18 to 1 is achieved so that with a motor speed of 3,200 r.p.m., the drill steel 34 will be rotated at 178 r.p.m.

The speed of rotation of the air motor 36 may be varied by means of a throttle valve 64 (FIG. 4) disposed in a fluid supply passage or inlet 65 to the air motor 36. Therefore, as above indicated, the rotation of the external gear 52 causes rotation of torque shaft 24 by reason of the spline connection at 56. Rotation of the torque shaft 24 is transmitted to the drill steel 34 through the spline connection at 38 thus accomplishing the desired central drive of the torque shaft 24.

Impact means In order to deliver impact blows to the drill steel 34 and drill bit 152 simultaneously but independently from the rotation of the torque shaft 24, impact means, such as an axial motor having a hammer piston 66, is provided.

The hammer piston '66 (FIGURE 1) is provided with an axial bore 68 through which torque shaft 24 extends, and is reciprocably mounted in an axial motor cylinder 70 which is closed at one end by a conical wall '72. This wall 72 and a rearwardly spaced wall 74 define a plenum chamber 76 which receives fluid, such as air, under pressure from a supply port 78. Toprevent fluid leakage from plenum chamber 76,.the space between

walls

72 and 74 are made fluid tight by seals 80. As shown in FIGURE 1, a spool type valve 82 is disposed in plenum chamber 76 to control flow of pressure fluid to cylinder 70 through suitable porting to thereby effect reciprocation of hammer piston 66.

The reciprocating movement of the hammer piston 66 is accomplished by air being admitted through passage 84 and port 86 to the front supply cavity 88 of the hammer piston 66 (FIGURE 1) to move or drive the hammer piston 66 rearwardly from the striking position,

as shown in FIGURE 1, to the retracted position until its front edge 90 uncovers the front kicker port 92, as shown in FIGURE 7. The uncovering of the port 92 permits pressurized air to pass therethrough and move or drive valve 82 rearwardly causing a valve edge 94 thereof to move from the position shown in FIGURE 1 to the position shown in FIGURE 8, biased toward the back end 26 of the rock drill 22. As the valve 82 moves toward the back end 26 of the rock drill 22, it closes the passage 84 to shut off the air supply to the front supply cavity 88 of the hammer piston 66. At the same instant as the spool type valve 82 is moving to close passage 84 it exposes a rear supply port 96 (FIG. 8) which emits air through a rear supply cavity 98 to slow down and stop the hammer piston 66 in the retracted position of FIGURE 7.

Pressure then rapidly builds up in the rear supply port 96 and begins to push or drive the hammer piston 66 forward from the retracted position shown in FIGURE 7 to the striking position shown in FIGURE 1, toward the drill steel 34. As the hammer piston 66 is moving back to the striking position shown in FIGURE 1, an exhaust port 180 is uncovered thereby exhausting the front supply cavity 88 to the atmosphere. As the hammer piston 66 moves forwardly, a back edge 102 thereof uncovers a back kicker port 104, as shown in FIGURE 1, and permits pressurized air to enter a cavity 106a and act against a kicking flange 106 of the valve 82 (FIG. 1) thereby causing valve edge 94 to move forwardly toward the drill steel 34 and permit air to enter the front supply cavity 88. The back edge 102 of the hammer piston 66 now moves forward thus opening the rear supply cavity 98 to exhaust the air from the front supply cavity 88.

Thereafter the cycle of the hammer piston 66 is repeated. As the hammer piston 66 reciprocates, it imparts to the shank piece 108 or back end of the drill steel 34 impact energy which is, of course, transmitted to the drill steel 34. Thus it can be seen how impact energy is supplied to the drill steel 34.

In order to supply heat to front or bit end 110 of the drill steel 34 .and thus .to heat the rock formation 112 being drilled, a heating means such as a burner nozzle assembly 114 is provided.

Heating means The burner nozzle assembly 114 or heating means, shown in FIGURES 1 to 3, is provided with a tube 116 which extends substantially the full length of the rock drill 22 from the bit end 118 of the drill steel 34 to the back end 26. At the bit end 118 of the tube 116, a standard fuel ejector 128 (FIGURE 2) is positioned to receive a fuel, such as kerosene or other hydrocarbon fluids, and to eject the fuel into an external combustion chamber 122. The fuel is delivered to the fuel ejector 120 by a fuel pipe 124 which is flow connected to or communicates with .a fitting 126 threaded on the back end 26 of the rock drill 22. The fitting 126 is adapted to receive the discharge line (not shown) of a fuel pump (not shown) which serves as the fuel supply to the burner nozzle assembly 114, and forms no part of the present invention. The fuel pipe 124 is secured at its lower end within a bore 127 (FIGURE 2) in the nozzle end .136 of the burner nozzle assembly 114 through whichthe fuel flows to fuel ejector 120 for discharge into the internal combustion chamber 122.

A combustion supporting medium, such as gaseous oxygen, is supplied to the internal combustion chamber 122 by an oxygen supply means (not shown), connected to an oxygen fitting 128 which is threaded on the back end 26 of the rock drill 22 (FIGURES 1 and 3). The oxygen flows through the oxygen fitting 128 to a longitudinally disposed oxygen pipe .130, secured within the tube 116, which extends downwardly and is connected at its lower end 138 to a header 134 journalled in the nozzle end .136 of the burner nozzle assembly 114, as shown in FIGURE 2. Header 134 has a bore 132 providing communication for oxygen pipe 130 or a discharge foroxygen into the internal combustion chamber 122. The lower end .138 of the oxygen pipe 130, can be connected in the header 134 by any number of well known methods, such as the ball joint connection shown in FIG- URE 2 to allow for the rotation of the drill bit 152.

The fuel and oxygen mix in internal combustion chamber 1'22 and upon combustion therein a hot high viscosity illame leaves the nozzle end 136 through outlet 144. The start of combustion in combustion chamber 122, can be accomplished by a number of igniting methods known to those skilled in the art as for example a spark gap or carbon are fed by electrical conductors (not shown) connected to a source of power (not shown). The combustion chamber is lined with a layer .of insulating material 145 (FIGURE 2) to insulate the drill bit 152 from the heat generated in the combustion chamber 122.

Lubricating means In order to provide lubrication to the front end 28 of the rock drill 22, an inlet 146 is provided in the back end 26 of the rock drill 22 which communicates with the tube 116 and is 'adapoted to receive .a lubricant supply outlet, such as a flexible hose (not shown) which supplies lubricant, such as water. The lubricant flows through the tube 116, around the pipe 124-, and enters an annular space 148 to cool the nozzle end 136, and is then discharged from the nozzle end 136, through a plurality of circumferentially arranged radial ports 150 (FIGURE 2) located in the drill bit 152 for cooling the drill bit 152 and for quenching .and moistening detritus which is separated from the rock formations by the flame.

Thus the rock drill 22 drills holes (FIGURE 1A) in rock formations by use of heat, rotational drilling, and impact blows.

Operation- Although the operation of the apparatus should be apparent from the foregoing description, a brief description of such operation will now be made for purposes of summary and simplification. A fuel and a combustion supporting medium are individually fed by

pipes

124 and 130, to an internal combustion chamber 122 wherein they are ignited by means (not shown) and form a flame which protrudes past the drilling member or drill bit 152 to heat the rock formations to be drilled thereby. The heating of the rock formations serves to produce internal stresses in the rock formations thus reducing their resistance to mechanical drilling.

The air motor 36 provides torque to rotate the torque shaft 24, at a desired speed, through

gears

48, 50 and 52. The torque shaft 24 in turn delivers torque to rotate drill steel 34 and its drill bit 152 to drill the rock formations.

In addition, operating independently but coaxially with the torque shaft 24, the reciprocating percussive member or hammer piston 66 delivers impact blows to the drill steel 34.

The flame, which may range in intensity from 200 F. on up to 1000 F., is moved over the surface of a rock formation at a rate of speed designed to produce enough internal stress in the rocks, to allow fairly light percussion blows from the hammer piston 66 to cause heavy spalling of the rock formations which rock formations when rotationally drilled by the drill bit 152, are reduced to fine material that are easily removed. Thus holes of any desirable diameter are produced in rock formations economically and accurately.

Alternative embodiments Alternatively, as shown in FIGURE 9, heat can be provided in front of the drill bit .152" by electrical means such as a spark gap 162" or carbon are fed by electrical conductors 164" connected to a power supply source (not shown).

Further alternatively it will be understood that the heating means shown in FIGURES 1 and 1A can be employed in combination with a conventional rotary type rock drill to form a rock drill having rotary drilling means and heating means for drilling rocks.

Still further alternatively the heating means shown in FIGURES 1 and 1A can be employed in combination with a conventional percussive rock drill to form a rock drill having percussive means and heating means for drilling rocks.

Still further, alternatively rock formations can be heated by the use of chemicals which are delivered to rock formations by tube means such as the tubes 116 and shown in FIGURE 1. There are many such well known chemicals which when mixed on the rock formations would react to create suflicient heat to cause easy spalling of the rocks. It is of course understood that the

tubes

116 and 130 would be constructed of material that could not be harmed by the chemicals.

It will be recognized by those skilled in the art that the objects of the present invention have been achieved by providing an improved rock drill which utilizes the combination of heat, rotary drilling, and percussion to drill holes in rock formations easily and more efficiently by introducing a flame or heat source ahead of the drill bit to cause sutlicient internal rock pressure for easy spalling of the rock formations.

While in accordance with the patent statutes a preferred embodiment of the present invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

I claim:

1. A rock drill comprising:

( a) casing means;

( b) impacting and rotational driving motor means disposed in the casing means;

(c) a drilling tool supported in the casing means and extending therefrom;

(d) the drilling t-ool being operatively connected to the motor means to be driven thereby and having means outside of the casing means for engaging and mechanically drilling a rock formation; and

(e) means disposed in the mechanical drilling means for heating the rock formation to be drilled for producing internal stresses therein to facilitate mechanical drilling.

2. A rock drill in accordance with claim 1, and further comprising:

(a) inlet supply means disposed in the drilling tool, communicating with the heating means and being connected to the casing means to provide a connection to a supply source.

3. A rock drill in accordance with claim 2, wherein:

(a) the inlet supply means extends through the motor means.

4. A rock drill in accordance wit-h claim 2, and further comprising:

(a) supply means being disposed in the drilling tool for providing lubrication to the mechanical drilling means, extending into the casing means and through the motor means, and being connected to the casing means to provide a connection to a supply source.

5. A rock drill comprising:

(a) casing means;

(b) impacting and rotational driving motor means disposed in the casing means;

(c) a drill steel supported in the casing means and extending therefrom, and being operatively connected to the motor means to be driven thereby;

'(d) a drill bit connected to the drill steel outside the casing means for engaging and mechanically drilling a rock formation when the drill steel is driven; and

(e) a burner nozzle assembly disposed in the bit for providing heat to the rock formation to be drilled for producing internal stresses therein to facilitate mechanical drilling.

6. A rock drill in accordance with claim 5, and further comprising:

'(a) electrical spark gap means disposed in the nozzle assembly to provide a spark when connected to a source of electrical energy for creating heat in the nozzle assembly to be provided to the rock formation to be drilled.

V 7. A rock drill in accordance with claim and '(a) the casing means having inlet means adapted to receive fuel for combustion in the burner nozzle assembly and an oxidizing agent to support such combustion; and

'(b) a pair of conduits disposed in the drill and extending into the casing means each communicating with the inlet means at one end and with the burner nozzle assembly at the other end to provide a flow path for fuel and a flow path for the oxidizing agent.

8. A rock drill in accordance with claim 7, wherein:

(a) the pair of conduits extend through the motor means.

9. A rock drill in accordance with claim 7, wherein:

(a) one of the pair of conduits is disposed within the other.

10. A rock drill in accordance with claim 7, and having lubricating means comprising:

(a) inlet means in the casing means adapted to receive lubricant;

'(b) a conduit disposed in the drill steel which extends into the casing means and communicates with the inlet means to receive lubricant therefrom;

(c) an annular chamber defined between the bit and the burner nozzle assembly; and

(d) the annular chamber communicating at one end with the lubricant conduit and having discharge ports at its other end extending through the bit. 11. A rock drill in accordance with claim 10, and:

' (a) the pair of conduits and the lubricant conduit being disposed one within the other and extending through the motor means.

References Cited by the Examiner UNITED STATES PATENTS 595,969 12/97 Plumb 74-830 1,284,398 11/18 McKinlay --11 XR 2,111,872 3/38 Rea 17511 XR 2,675,994 4/54 Smith et al 17515 XR 2,810,549 10/57 Morrison 175--296 XR 2,882,016 4/59 Aitchison et a1 175-14 2,935,303 5/60 Royer et al. 175-14 3,004,137 10/61 Karlovitz 175-16 XR 3,045,766 7/62 Fleming 17514 3,093,197 6/63 Freeman 17514 3,103,251 9/63 Browning 175-14 CHARLES E. OCONNELL, Primary Examiner.

Claims

1. A ROCK DRILL COMPRISING: (A) CASING MEANS; (B) IMPACTING AND ROTATIONAL DRIVING MOTOR MEANS DISPOSED IN THE CASING MEANS; (C) A DRILLING TOOL SUPPORTED IN THE CASING MEANS AND EXTENDING THEREFROM; (D) THE DRILLING TOOL BEING OPERATIVELY CONNECTED TO THE MOTOR MEANS TO BE DRIVEN THEREBY AND HAVING MEANS OUTSIDE OF THE CASING MEANS FOR ENGAGING AND MECHANICALLY DRILLING A ROCK FORMATION; AND (E) MEANS DISPODED IN THE MECHANICAL DRILLING MEANS FOR HEATING THE ROCK FORMATION TO BE DRILLED FOR PRODUCING INTERNAL STRESSES THEREIN TO FACILITATE MECHANICAL DRILLING.