US2866622A - Electric flame boring apparatus - Google Patents

Description

Dec. 30, 1958 R. w. MURRAY ELECTRIC FLAME BORING APPARATUS 2 Sheets-Sheet 1 Filed Oct. 8, 1954 INVENTOR. Robert W. M urroy By Mafi ATTORNEY Dec. 30, 1958 R. w. MURRAY ELECTRIC FLAME BORING APPARATUS 2 Sheets-Sheet 2 Filed Oct. 8, 1954 INVENTOR. Robert W. Murray ATTORNEY United States Patent ELECTRIC FLAME BORING APPARATUS Robert W. Murray, Denver, Colo.

Application October 8, 1954, Serial No. 461,247 8 Claims. c1. 255 4.8

This invention relates to flame boring, and more particularly to flame boring into the earth with an electric arc, a primary object of the invention being to provide a novel and improved method, and novel and improved apparatus for arc-flame boring into the earth.

Reference is made to my copending application for Flame Boring Apparatus, filed February 23, 1954, Serial No. 411,958, now Patent No. 2,822,148, dated February 4, 1958. Certain features of the apparatus disclosed in that application are incorporated in the present structure along with improvements hereinafter described in detail. The objects of the present invention in common with the objects of the prior copending application are to provide such novel and improved method and apparatus for arc-flame boring a shaft into the earth which: (a) is operative to drill to great depths; (b) continuously scavenges drilled particles avulsed from the bottom of the hole; (0) operates under water; and (d) provides a simple, low-cost method for drilling wells with apparatus which may be constructed as a complete, compact unit adapted to be suspended by a cable and eliminating the need for large derricks and expensive and heavy equipment used in ordinary drilling operations.

Further objects of the present invention are to provide a further improved method and apparatus for arcflame boring a shaft into the earth which: (1) permits the formation and maintenance of a low-voltage are against earth and rock formations of exceedingly high resistivity; (2) reduces the power requirements for such flame boring to a necessary minimum; (3) permits operation of the apparatus with conventional electrical generating equipment; and (4) furnishes the industry a method for producing an are against substances of high electrical resistivity.

With the foregoing and other objects in view, all of which more fully hereinafter appear, my invention comprises certain operations and steps, and combinations, constructions and arrangements of .parts and elements as hereinafter described, and as defined in the appended claims and illustrated in the accompanying drawing, in which: I

, v Figure l is a vertical elevation view, partly in section, vof an arc-flame boring apparatus constructed for operation in accordance with the principles of my invention,

and with a portion of a shaft beingdrilled into the earth being indicated.

Figure 2 is a plan view of the apparatus, with the supporting cables and ductsin section as taken from the indicated line 2-2 at Fig. 1.

Figure 3 -is a transverse sectional view as taken from as taken from Figure 6 is a sectional elevationview of aportion of "ice the apparatus as taken from the indicated line 6- -6 at Fig. 4. t

Figure 7 is a fragmentary sectional detail as taken from the indicated line 7-7 at Fig. 4 but on an enlarged" scale.

Fi ure .8 is a fragmentary sectional detail as taken from the indicated line 88 at Fig. 4 but on an enlarged Figure 10 is a fragmentary sectional detail as taken from the indicated line 10--10 at Fig. 9. .1 I

Figure 11 is a fragmentary sectional portion, diagrammatic in nature, of the elements whichbring about the arcing, avulsing and scavenging operations in accordance with the principles of the invention.

Figure 12 is a fragmentary sectional detail of an element which may be embodied in an alternate form of the apparatus. t The art of flame boring into the earth or into a rock face is old and it is well known that practically all types of rock will yield in one way or another to intense heat, especially where there is a sudden change in tempera ture. However, the conventional operation is expensive, using large quantities of oxygen and fuelgas, and the problems of scavenging the hole whenever the depth of the hole exceeds a few feet become almost insurmount able. With such in view, the present invention was conceived and developed to take advantage of, and to use, the intense heat which can be obtained in an electric are for flame boring operations.

In essence, my invention consists of a method and apparatus which is compatible with that disclosed in my copending application, hereinbefore identified, to include the operations of: forming an are at the bottom of a shaft which quickly heats that portion of the rock under the arc to an intense temperature; thence, sweeping the are about the bottom face of the hole to spall, melt or deteriorate the rock; and thence avulsing the deteriorated rockvand scavenging it from the hole. As a step beyond the operations disclosed in said copending application, the present invention includes operations for the formation of an are at a rock face at relatively low voltages.

The high resistivity of many earth and rock formations will not permit a favorable application of an electric arc since the power and voltage requirements become excessive and the present invention is concerned with a novel and improved method for forming an electricarc against high resistance formations. f I

In its broad aspect, my improved method involves the operation of preparing the surface of the rock face to be disintegrated by the are, such as the bottom of a shaft, in such a manner as torender it a conductor of electricity. An electrical circuit, properly gr0un'ded, in-

cludes a live electrodewhich is adapted tostrike'the proper voltage an arc is formed at the electrode point of contact and the heat of such arc almost immediately melts the rock at the point of contact to commencethe disintegrating operation. I m 5 This melting ofthe rock almost immediately changes the regimen of the electrical current because most rock,

especially rocks containing silica, are good conductors of electricity when heated to the melting point. Therefore, even though the prepared low-resistance surface is destroyed or disintegrated at the point of the arc, the are is maintained and the current, flows through the Patented Dec. 30, 1958 identified copending application, salt deposits on the rock surfacemay formasthearcforms avapor. pocket in a salt-watersolution; AJIIOIO: eflicient action,..howeve1r, is obtained by a direct deposit of an electrical conductor directly upon the rock surface,.such being easily accomplished. with. the conductor; in.: a-. comminuted. or granular form. The conductor may be metal powder, varioussalt formations, .or even .amixture .of. metal and salt... Metal powder. or: filings areto. bev preferredas one ingredient of the conductor since such particles ,will tend. to enter. thesppol. of.melted.rock at the. arc to further increase its conductivity.

Itfollows that a flame boring operation which incorporates the. conductor. deposit upon. the rock surface. may be accomplishedwith apparatus :which provides for the continuous deposittofsuch conductor upon the rock surface, arcingv electrodes. which. sweep across the surface. to. disintegrate the rock and. meansfollowing the electrodes which avulse and'scavenge the disintegrated rock particles, and the accompanying drawing is illustrative of such apparatus.

Referring more particularly to the drawing, the flame boringunit therein depicted is. adapted to drill a well shaftto any-desired depth, operate under water and use water circulation. to scavenge the drilled particles. This unittis formed as anelongated cylindrical body having arotatable drill head'16 at its-base. The body is suspended from a cable 17, and power cables 18 and fluid feed lines 19 and 20'are attached .to the top of the body and are adapted to belowered into a shaft alongside the cable 17for providing the necessarypower and fluid circulationfor operation ofthe unit. It is anticipated thatconventional reeling, arrangements willbe used for holding and'lowering the cable and power-feed lines into the shaft 8' and. that conventional power generating and pumpingequipment will be stationed at the top of the shaft for operation of theequipment.

The body 15'is substantially the same as that disclosed in .the hereinbefore identified copending application, and is formed as an end-closed cylindrical case having a diameter necessarily smaller than the. diameter of the shaft S and of length sufiicient to contain driving rnechanisms hereinafter described. The top of this body case includes an aperture 21 to receive the electrical cables .18 and an aperture 22 to receive the feed lines 19. and 20.

The feed line 20 is centered within the feed line 19 and these lines are attached to corresponding tubes 23 and 24 respectively which are axially centered in .the case 15 with the outer tube 23forming, a shaft tube. to carry rotative elements of the driving mechanisms. The. cable 17 is attached to a bail 25 which upstands from the top of ,the case 15."

There. is provided four wall guides 26, in opposing pairs, at each' end of the case.which are shaped as resilient .loopsto outstand from the. case and bear against thewall of the shaft S to. hold the casein concentric alignment within the shaft. Knife edges. 27 outstand from thebearing surface ofeach'. guide in axial alignmentiwith respect to the unit to grip the walls of the shaft to permit vertical movement of the body within the shaft but to. prevent rotation and hold the body against'torque caused by rotation ofjthedrill head16.

The drill head 16 isrotated' by an electric motor. 28 which is carried within the upperpoi'tion of thebody 15. The armatureof thismotor is 'rot'atably mounted about the shaft tube 23 upon' bearings 29 at each end' thereof, while the field circumscribes the armature and is affixed to" the walls of. the body IS. The motor=is.powered by selectedleads *from the power cables 18 in conventional manner. a a

- Thetarmature of themotor 28 includs a shaft portion 30 which is toothed to intermesh with a planetary gear speed-reducing train 31 which includes rotative elements mounted upon the axial shaft tube 23 and other elements carried upon the frame 15 which need not be described in detail. The terminal rotative member of this train 31 is attached to the shaft 32 of the drill head 16 as at a connective link 33 about the tube 23.

The drill head shaft 32 isa tubular member with a substantial portion being in the lower section of the body 15 and therein mounted upon spaced opposing thrust bearings 34. The shaft tube 23 telescopes a short distance into the tubular passage in the shaft 32 with a sealing ring 35 between the walls of -the shaft tube 23 and shaft 32 to prevent leakage from. the passage to the interior of the body 15. The shaft 32 is formed as a central member circumscribed and encased within an insulating body which carries a plurality of commutator rings 36 between the thrust bearings 34, electrical leads 37 from the rings to the.head16,,and is :cylindrical.in section. within'the-body.15 and at the:opening orifice38. at the bottom of the-body, but square or. similarly fluted in the portion below the. body and inthe drill head lfi. A sealing ring circumscribes the shaft 32in the orifice. 38 to prevent leakage-ofwater-to. the interior of the body 15.

The drill'head 16includes a central hub 40 with .a fluted pocket at thetopwherein the fluted portion of the shaft 32. slidably and matingly extends for vertical reciprocation therein. The base of this pocket forms .a somewhat enlarged chamber 41 and the bottom of..the shaft 32 includes a peripherally outstanding rim 42 within this chamb'erwhich abuts. against the top of the chamber to restrict the withdrawal of.the shaft from the hub. A compression spring 43 encompasses the shaft 32 above the hub 40- to resiliently extend the hub 40toits limit of movement on the shaft as illustrated in the drawing, it being understood that a loading of-the body upon the drill head as in operation will. cause the head to move upon the shaft '32 against the force of the spring. To facilitate assembly of'the unit, the drill head hub 40 may-be formed as a longitudinally split, separable member, which is locked together by bolts, weldingor in any other suitable manner after assembly of the unit'with shaft 32 within the hub 40.

This drill head 16 is encased within a pair of semicircular hoods 44'which lie in opposition with each other with their outer wall portions 45' defining a common cylindrical surface which is substantially the diameter of the shaft 8.. The inner opposingjwall portions of these hoods extend substantially radially'from each side of thehub 40 to form.diametrically opposingtroughs 46, with the elements of each troughopposite the elements ofthe'other' to provide a rotativelyoperable unit..

The central. fluid. feed line 20 connects with tube 24 which extends through the body 15-within tube 23, through the passage in the shaft 32 to'the .chamber41 within hub 40 and there into a nipple 47 upstanding from the bottom of 'the' chamber with a reciprocally sliding fit to telescope into'the nipple'responsive to movement of the head 16upon the shaft '32." From thenipple, a passageway 48 bifurcates nearthe bottom of the hub. 40 and into hollow arms 49 which outstand from each side of the hub approximately degrees from the troughs 46. These arms 49extend to the 'circular walls 45 with their under edge being slightly above the baseofKthe head 16. A row of orifices 50 extend acrossthe under edge of each arm 49 to permit the-flow and spread' of a surfaceconductorsubstancewvhich will be fed to. the apparatus through the feedfline 20. Wh'eremetal particles are-.used it is anticipated; thatzthey'. wilLbe .carried in suspension in a conveyorliquid of. aicharacteriwhich will. not reducetheirrefictivenessa Such a.liquid;would be a brine solution.

Opposing-rowsnf ;arc electrodes:.&1.-aremounted;within casesi52. which outstandifrom therhub. 40 and extend to the circular walls 45 of the hoods 44 and are oriented to trail their adjacent conductor-spreading arms 49 with respect to rotation of the head. The cases 52 are preferably mounted against the diametrically opposing inner wall sections 53 of the hoods 44 which form one side of the troughs 46. A singular electrode 51' is also mounted at the center of the head underneath the hub 40. All electrodes depend from their mounts to the base of the head. Power is supplied to these electrodes from the leads 37 which are embedded in the shaft 32 in the insulated portion thereof, and extend from the shaft through slot-shaped orifices 54 and into the cases 52. The slotshaped orifices 54 permit movement between the shaft 32 and hub 40 without injury to the leads 37 as clearly shown at Fig. 10. The lead 37' to the central electrode 51' likewise extends through a slotted orifice in the hub 40. For operaiton, the leads of cables 18 extend through the body 15 to brushes 55 which connect with the commutator rings 36 to complete the circuits.

The wall section 56 forming the side of each trough 46 opposite the wall section 53 forms an upper flange of an arm 57 which outstands from the hub 40 with its underedge at the base of the head 16. This underedge is thereby adapted to form a grounding surface, contacting against the bottom of the shaft S and in trailing relation with the electrodes and conductor-spreading arms 49 to complete the operative circuit, although it is to be understood that other points of grounding as at the point of electrical generation at the top of the shaft will effectively operate the apparatus.

The troughs 46, defined by walls 53 and 56 of the opposing hoods 44 to radially outstand from the hub 40 are open along their bottom at the space between the respective walls, and with the lower edge of the leading wall 53 being above the arm 57 to provide an exit for excess conductormaterial and avulsed rock particles torn from the bottom of the shaft by the action of the arcs. The leading face 58 of the arm 57 is sloped to provide a scooping action, but with the leading edge 59 thereof being blunted to pile up a certain amount of conductor material as the arm moves about the shaft and thereby provide a better ground for the arc.

The fluid feed line 19connects to tube 23, with the passage thence through shaft 32 and to chamber 41 in the hub 40. The passage extends from the chamber to a pair of leads 60 to 'a cylindrical chamber 61 in each arm 57. A slotted orifice 62 extends from each chamber to discharge from the leading face in an upward direction to provide for a jet-pump action to facilitate the movement of particles from the bottom of the shaft as clearly illustrated by the indicated arrows at Fig. 11. To provide an efiicient passage for such jet action, the bottom edge of the leading wall is turned upwardly as at 63 and the leading face of the wall 56 above arm 57 is flared forwardly as at 64.

In operation, the apparatus is lowered into a shaft S, and the head 16 is rotated. The conductor substance is fed into the apparatus through line 20 to be spread upon the bottom of the shaft. The scavenging fluid, which may be a conventional water-bentonite mixture, is fed into the apparatus through line 19 and discharges through orifices 62. The electric current commences to flow as soon as there is a spread of conductor material upon the bottom of the shaft sufficient to permit the arm 57 'to act as the ground electrode. Once arcing commences, avulsion and scavenging of the rock will follow. The heat generated will fill the hoods with steam and the operation at the bottom of the shaft will be substantially in a vapor pocket. The flow of liquid through orifices 62 will reduce the pressure within the hoods and cause movement of material therefrom. One electrode will be spaced sufficiently close to the wall of the shaft to provide for a reaming action as the drilling proceeds and sum 6, cient conductor material will be moved to the center of the shaft to start the center electrode 51'. r

It is to be recognized that various modifications and alterations to the apparatus are possible without departing from the spirit of the invention. One such modification involves the use of an extended drill stem with the rotating machinery at the ground surface above the shaft.

- Another modification is illustrated at Fig. 12 which shows a hollow electrode 66 which is connected to a feed line supplying conductor fluid. Yet another modification involves the use of pairs of electrodes and use of the scraper blade as an independent unit and not a ground. In still another modification, the two scraper blades may be the electrodes and arcing occurs along the edges of the scraper blades.

Hence, it follows that my desire for protection is limited, not by the details and constructions herein illustrated and described, but only by the proper scope of the appended claims.

I claim:

1. Electric flame boring apparatus for boring a shaf into the earth, including, in combination, an arm carrying electrodes adapted to contact the earth surface at the bottom of the shaft, a head carrying said arm adapted to rotate within the shaft and move said electrodes across the bottom surface of the shaft in circular paths, a second tubular arm outstanding from said head in front of the electrodes with respect to their movement, a passageway in said head interconnecting the tubular arm with a supply of conductor material in a flowable state, orifices across the tubular arm adapted to permit the deposit of a I layer of conductor material upon the bottom surface of the shaft as the head rotates with the arms, and a third arm outstanding from said head behind the electrodes with respect to their movement adapted to bear against the bottom surface of the shaft and thereby form a ground when in contact with said conductor material.

2. The apparatus defined in claim 1, wherein said third arm includes an orifice and passageway therethrough, and a passageway in said head interconnecting with the arm passageway and means adapted to provide a supply of liquid into the passageways and from the orifice.

3. The apparatus defined in claim 1, wherein said electrodes and said second arm are enclosed by a hood.

4. The flame boring apparatus defined in claim 1, wherein the electrode-carrying arm is enclosed within a circular hood having a substantially circular sidewall and a pair of closely-spaced substantially radially disposed wall sections spaced close to said third arm and forming an upwardly directed passageway adjacent to the arm.

5. The flame boring apparatus defined in claim 1, wherein the electrode-carrying arm is enclosed within a circular hood having a substantially circular sidewall and a pair of closely-spaced substantially radially disposed wall sections spaced close to said third arm and forming an upwardly directed passageway adjacent to the arm, and upwardly directed jet-means associated with said arm adapted to flow liquid upwardly through said passageway at high velocity whereby to move particles piling upon said third arm upwardly and through the passageway.

6. Rock avulsion apparatus for forming, maintaining a and moving an electric arc across the surface of a rock mass of high resistivity and for avulsing heat disintegrated rock particles from the surface of the mass, including, in combination, moving and power supply means, an

electrode carried by said means adapted to move along a ReferencesCitedfimthe file :of .this patent:

UNITED 'STATES PATENTS Coffin June 18, 1889 Aarts et a1 Feb. 21, 1933, Aarts et a1 Mar. 5,1935 Armstrong May 13, ,1941

FOREIGN PATENTS Switzerland Sept. 1, 1931

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