US2327499A - Process of and apparatus for working mineral materials and the like - Google Patents

Description

Aug 24, 1943- c. J. BURCH 2,327,499

PROCESS OF AND APPARATUS FOR WORKING MINERAL MATERLS AND THE LIKE Filed April 18, 1941 2 sheets-sheet 1 .if wf 55 57 j@ 1 3g 3-A .a7 i /5 /g ,y l /1/\ 4 Ver;

/4 /g' 209/5 [1f 20 la 56 /4 /5 /5 50 45 0 g Il /7 464g 27 j /6 49 A 5 0 J) Mgg. l Jy \NVENTOR CHARLES J. BURCH ENi ATTORNEY Aug. 24, 1943. c. J. BURCH 2,327,499

PROCESS OF AND APPARATUS FOR WORKING MINERAL MATERIALS AND THE LIKE Filed April 18, 1941 2 Sheets-Shea?I 2 INVENTOR CHARLES J. BURCH ATTORNEY Patented Aug. 24, 1.943

PROCESS OF AND APPARATUS FOR WORK- FEE MINERAL MATERIALS AND THE Charles J Burch, Kenmore, N. Y., assignor to The ilrliide Air Products Company, a corporation of Application. April 18, 1941, Serial No. 389,116

(Cl. Z55-1.8)

19 Claims.

This invention relates to a process of'thermally working, as by piercing, cutting, or grooving, minerals and mineral-like substances. In addition, the invention also relates to apparatus for thermally working minerals and the like, and more particularly for the piercing of deep holes for blasting or other purposes.

In application Serial No. 268,634, filed April 18, 1939 by R. B. Aitchison, C. W. Swartout, and V. C. Williams, there are disclosed and claimed two methods of procedure for the thermal working of mineral materials and the like, namely, by a controlled spalling method wherein the mineral material, such as quartzite, is spontaneously disintegrated by the application of an oxyfuel flame, and the disintegrated material is removed from the zone of 'heating in the unfused condition; and by a melting method wherein the' mineral material, such as iron ore, is fused by the Oxy-fuel flame before removal from the zone of heating. Choice of the proper method to follow depends primarily upon the type of mineral to bc worked. Some minerals, such as quartzite,'react readily to 4the spalling process, but minerals which do not spall, such as iron ore, must be melted. Wherever possible, it is most advantageous to employ the spalling process because of its simplicity and economy. It has now been found that a third class of mineral materials exists characterized by a predominant tendency to spall in response to heat, but having a minor proportion of constituents which are loosened only partially from the mass, thereafter melting anc adhering to the mass being worked. Fused particles thus may accumulate in the hole or the like and eventually form a plug of slag preventing the advance of the mineral working operation. Examples of mineral materials of the third class are granite, dolomite, and some sand stones having a small proportion of iron impurities; and many other well known minerals may be found to exhibit the same properties. By the present invention, minerals of the third class may be thermally worked by a modification of the spalling method of procedure.

Ancillary problems solved by the invention are the production of blasting and like holes having y uniform diameters; and the provision of blowtorches, readily adaptable for use in different types of mineral materials, which will permit any of a plurality of interchangeable flame-producing tips to be used according to the desired mode of operation, as well as permitting damaged tips to be replaced quickly and easily.

The principaly object of the present invention,

therefore, is the provision of a novel process of, and suitable novel apparatus for rapidly and economically thermally working minerals and the like of the third class discussed above. Another object is the provision of a process of, and apparatus for, thermally piercing holes in mineral materials and the like of the type wherein intense heat causes separation of particles of material from the mass by spalling, but wherein some particles, which are only partially loosened, tend to adhere to the mass and fuse. Other objects are the provision of a process and apparatus for thermally producing holes of uniform diameter in mineral materials and the like; and the provision of rock piercing blowtorches so constructed that flame-producing tips may be removed and replaced at will, either with identical tips or interchangeably with diierent types of tips.

'I'he 'above and other objects, and the novel features of the invention, will become apparent from the following description, having reference to the annexed drawings wherein:

Fig. 1 is a longitudinal' sectional view, partly in elevation, showing one novel form of blowtorch, in position within a hole in a mineral mass, for performing the process of the invention;

Figs. 2 and 3 are cross-sectional views taken along the lines 2-2 and 3-3, respectively, in Fig. 1;

Figs. 4 and 5 are sectional views taken along the lines 4 4 and 55, in Fig. 2;

Fig. 6 is a front end elevational view of the blowtorch of Fig. 1;

Fig. '7 is a sectional view taken along the line l-1 of Fig. 6, showing only the removable tip of the blowtorch of Fig. 1;

Fig. 8 is a front end View of another tip which may be used on the blowtorch of Fig. 1, interchangeably with the tip of Figs. 6 and '7;

Fig.v 9 is a sectional view taken along the line 9--9 of Fig. 8; I

Fig. 10 is a. longitudinal sectional view of a front end of a blowtorch similar to that of Fig. 1, but employing still another form of interchangeable tip;

Fig. 11 is a longitudinal sectional view of still another form of tip;

Fig, 12 is a longitudinal sectional view of a modied form of rock piercing blowtorch, shownin position for piercing a hole in a mass of mineral material by the process of the invention;

Fig. 13 is a front end view of the blowtorch of Fig. 12; and

1 mass.

Fig. 14 is a sectional view taken along the lines I4-I4 of Fig. 12 or Fig. 13.

In accordance with the invention there is provided a novel process of thermally piercing, cutting, grooving, or otherwise Working masses of mineral material and the like of the type wherein intense heat causes separation of particles of material from the mass by spalling, but wherein some particles tend to adhere to the mass and fuse, which process comprises continuously applying intense heat to such a mass to separate materials therefrom and form a hole, cut, groove, or the like; removing the separated material from the hole, cut, groove, or the like thus formed; and, concurrently with the heating operation, mechanically separating partially loosened adhering particles of material from the Also in accordance with the invention, there are provided nove1 heating instrumentalities, such as blowtorches, for performing the process described generally above, comprising means for applying heat to a mass of the mineral to be worked, as by an Oxy-fuel ame of sufcient intensity to loosen material from such mass, and means for mechanically scraping free and disintegrating any partially loosened material so that it may be readily removed from the zone of heating.

For the sake of simplicity, the process of the invention will be described hereinafter, by way of example only, as specifically applied to the piercing of holes of generally circular cross-section straight into masses of minerals and the like; and the various forms of heating instrumentalities specifically described, also by way of example, are particularly adapted for the piercing of such holes. It is to be understood, however, that the invention is not to be limited to the specic embodiments of the process and apparatus described, and that the invention is applicable not only to the production of holes extending straight into a mass of material, but also to the production of holes in the nature of cuts and grooves. For convenience, the terms acetylene and oxygen will be used hereinafter to indicate, respectively, any suitable fluid fuel, either alone or carrying in suspension a metallic or other powder, and any suitable combustion-supporting gas.

As shown in Figs. 1 to 7, inclusive, one form of blowtorch embodying the principles of the invention comprises a rear body II having a boss I2 on its forward end over which an elongated tube I3 is secured. The tube I3 may be of any desired length, in accordance with the depth of hole to be pierced, which in some instances may be as much as feet deep. An adaptor body I4 is secured within the forward end of the tube I3 and is additionally connected to the rear body II by three conduits I5, I6, and II arranged side by side within the tube I3. The tube I3 and the conduits I5, I6, and II may be secured to both bodies II and I4 by silver soldering or other suitable means.

The adaptor body I4 is cylindrical in shape and is provided on its forward end with a series of concentric annular sharp-edged seats I8, I9, and 20 of progressively decreasing diameter toward the front of the blowtorch- Acetylene gas is supplied to the blowtorch through an inlet 22 and a metering orifice nipple 23 threaded into the inlet, to which is removably coupled, as by the coupling nut 24, a valve body 25 secured in the end of a supply hose 25. From the inlet 22, the acetylene passes through a passage 2| in the rear body iI to the conduit I1 and is conducted to the adaptor body I4, from which it is discharged axially through a passage 21 having an opening in the front of the adaptor body concentric with the annular seats I8, I9, 20. Oxygen gas may be admitted through the inlet connection 28 to a. passage 30 in the rear body II, which conducts the gas to the conduit I6 leading to a passage 29 in the adaptor body I4, the passage 29 having an opening'in the front of the body I4 on the annular shoulder between the annular seats I9 and 20.

A cooling medium such as water, which in some instances may also be used for ejecting detritus from a hole, is brought into heat-exchange relationship with the blowtorch through an inlet connection 32 in the side of the tube I3 connected, aS by the coupling nut 33, to a removable valve body 34 carried in the end of a supply hose 35. Water thus circulates in the spaces formed between the inner wall of the tube I3 and the outer walls of the conduits I5, I 6, and I1, and also is conducted to the front of the adaptor body I4 through three spaced ducts 36 extending through the adaptor body and having openings in its front face on the annular shoulder formed between the seats I8 and I9.

The third conduit I5 establishes communication between a passage 3'I in the rear body II and a passage 38 in the adaptor body I4, which latter passage has a right angle bend within the adaptor body and opens to the side surface of the adaptor body in back of the seat I8. 'I'he conduit I5 may serve either to return cooling fluid from the front of the adaptor body I4 to the rear end of the blowtorch, from which it is then discharged through the nipple 39 threaded into the rear body II, or it may serve as a iiuid supply conduit, in which case fluid may be supplied to the nipple 39. The reasons for the alternative uses of the conduit I 5 will be described more in detail hereinafter.

The constructions of the adaptor body I4 and the tube I3, described in detail above, are such that any one of a plurality of tips 4I, removable and replaceable at will, may be secured over the adaptor Abody interchangeably in order to adapt the blowtorch for the most satisfactory and eilicient performance of the particular operation contemplated. As shown in Figs. 1 to 7 inclusive, for example, a tip 4I having a cylindrical bore 42 terminating at its front end in a conical bore 43 is threaded over the outside o-f the forward end of the tube I3 with the surface of the conical bore 43 abutting against the annular seats I8, I9, and 2U, thereby providing fluid-tight seals separating the several passages 21, 29, and 39 from one another and from the ducts 36. It is advantageous to construct the adaptor body I4 of a metal, such as Monel metal, so

o-f thetip 4I, which preferably is formed of a relatively soft metal such as copper.

A central passage 44 in the tip 4I is adapted to 'discharge acetylene in a centrally flowing stream from the front end of the blowtorch. Thereafter, the acetylene mixes with four small streams of gaseous oxygen discharged from the tip 4I, around and converging toward the acetylene stream, through four ducts 45 converging forwardly toward the axis of the blowtorch and one another, and communicating at their inner ends with the annular passage 46 between the seats I9 and 20 and the wall of the conical bore 43. When the combustible gas mixture thus produced outside of the blowpipe is ignited, an intense flame oi' the so-called diiusion type is produced which is suitable for piercing holes in minerals and mineral-like materials without the occurrence of iiashbacks within the blowpipe.

Two longitudinally extending tubular prongs or scraper 41 and 48, having closed ends, are

' secured, as by welding or brazing, to opposite sides of the tip 4I and overlie the front face of the tip. 'I'he prongs 41 and 48 project forwardly and laterally of the tip 4I for scraping from the lbottom and side walls Yof a hole being pierced any partially loosened material which may fuse and form plugs unless disintegrated, and also for the purpose of breaking up any plugs which may be fonmed during a piercing operation. For resisting the abrasive action of mineral materials, the leading surfaces or ends of the tubular prongs 41 and 48 are protected by layers 50 of a hard facing material, for example, a cobalt-chromiumtungsten alloy known commercially as Haynes,

Stellite alloy.

Cooling of the tip 4I, and of the prongs 41 and 48, is accomplished by water discharged into the annular space 49, between the annular seats I8 and I 9 and the wall of the conical bore 43, which passes through forwardly and outwardly inclined ducts I and 52 into the prongs 41 and 48, respectively. Water leaves the respective prongs through the two radial ducts 53 and 54 in the tip 4I, and enters an annular space 55, in back of the annular seat I8 between the cylindrical wall of the adaptor body I4 and the wall of the cylindrical bore 42 in' the tip 4I. Thence, the water is discharged from the blowtorch through the passage 38, the conduit I5, the passage 31 in the rear body II, and the nipple 39.

From the foregoing description it is evident that there has been provided a blowtorch com-- prising an elongated straight tubular member having front and rear ends, which is adapted to provide a flame adjacent to its front end. This tubular member which, in the specific embodiment shown, includes the rear body II, the front adaptor body I4, the tube I3, the conduits I5, I6, and I1, and the tip 4I, carries tooth means projecting therefrom adjacent to its front end constructed and arranged for disintegrating material loosened by the flame.

When piercing a hole 56 in a mass of material 51, such as granite, the intense diffusion type heating flame projected from the tip 4I causes material to spall oil continuously as the blowtorch is advanced; and the gaseous products of combustion exert a force upon th spelled particles to eject them from the hele.y As the blow- Itorch is advanced into the mass, it is rotated by the operator with a reciprocating motion to cause each of the prongs 41 and 48 to describe a half circle and scrape ori any partially loosened fragments of lmaterial froml the walls of the hole, particularly from its forward face. In the event that the mass of material being pierced is of a fully spallable nature, /for example quartzite, the prongs 41 and 48 ordinarily may. be dispensed with. However, some quartzite deposits embody thin strata of clay or like material, which may fuse under the action of the blowtorch flame. When such strata are encountered, the fused plugs may be broken up by the prongs 41 and 48 for ready removal from the hole.

Inasmuch as the tip 4I is removably threaded upon the elongated tube I3, a iiud-tight seal being maintained by applying lead to the threads of the tubular member before the tip is threaded thereon, the tip 4I may be readily removed and replaced by another tip. For example. the tip shown in Figs. 6 and '1, as described particularly be moistened before removal from a hole in orderto prevent contamination of the atmosphere with dust. 'I'he tip 58 shown in Figs. 8 and 9 is substantially identical with that shown in Figs. 6 and 7 except for the provision of a plurality of circumferentially arranged'rearwardly and outwardly inclined lateral ports 59 establishing communication between the cylindrical bore 69 and the external surface of the tip. These ports 5S are adapted to discharge streams of a debrisejection and/or wetting iiuid toward the mouth of the hole being pierced. When the tip 58 is used on the blowtorch shown in Fig. l, the debrisejection and blowtorch-cooling fluid, which may be either compressed air or water, for example, is supplied to the blowtorch through both the inlet 32 and the nipple 39 concurrently. Adequate circulation of cooling iiuid within the prongs 5! and 62 is maintained because the fluid pressure in the annular space55 (see Fig. 1) is reduced by the discharge of fluid from the blowtorch through the ports 59.

Still another form of tip which may be used is shown in Fig. 10. There, the tip 83 is useful when no scraping action is necessary, and when no auxiliary debris-ejection fluid is required, the pressure of the gaseous products of combustion being sufficient to eject all debris from a hole. In this modification, the tip 63 is provided with a eylindricalbore 84 of such a depth that the wall of the conical bore 69 at its inner end only engages the two seats I9 and 20 of the adaptor to provide an L-shaped annular chamber 86 within which the water or other coolant may circulate before being discharged through the passage 38.

The tip 61 of Fig. 11 is identical with the tip 83l of Fig. 10, except that the tip 61 is provided with a plurality of circumferentially arranged rearwardly and outwardly inclined ports 68 opening to the side surface of'the tip and adapted to communicate with the chamber 68 (see Fig. 10) for the discharge of rearwardly directed debris-ejection and/or wetting uid streams from the blowtorch. As in the modiiication of Figs. 8 and 9, the fluid, such as Water or compressed air, may be supplied to the blowtorch through both the inlet 32 and the nipple 39.

In a preferred form of blowtorch embodying the principles o f the invention, as shown in Figs. 12, 13, andv14, three concentrically arranged conduits 10, 1I, and 12, one surrounding the other in the order named, are connected at their rear ends to a rear body 13 having inlet connections W, O, and A, respectively, for supplying a cooling and debris-ejection iiuid, gaseous oxygen, and acetylene gas to the respective conduits. An adaptor body 14 is secured within the front end of the conduit 10 and is connected to the rear body 13 by the conduits 1I and 12 which are secured within bores in the adaptor body. The adaptor body 14 is formed with three annular shoulders 15, 16, and 11, of progressively smaller diameter toward the front, which provide two annular sharp-edged seats 18 and 19 for cooperapierced its forward face is usually approximately tion with a tip to provide seals. hemispherical in shape, the semi-circular scraper central passage 8| through the adaptor body 94 insures that the entire area of the face of the 14, and four eccentrically arranged passages 82 hole will be scraped free of clinging fusible parhaving openings on the annular shoulder 16, are 5 ticles of, material. vIn operation, during the adapted to supply acetylene and oxygen, respecpiercing of a hole, the blowtorch is positioned tively, to a tip from-the conduits 12 and 1|. A with the scraper 94 approximately on a diameter second set of eccentrically arranged passages 83 of the hole and in contact with a narrow zone of having openings on the annular shoulder 15 are material extending across substantially the entire adapted to supply cooling and debris-ejection 10 bottom face thereof, the tWO heating flames are fluid from the outer conduit 10 to a tip. applied to the bottom face on opposite sides of A tip s4, having a, cy1indrica1 cavityas and the scraper to separate material from the mass, a conical bore 86 at the bottom of the cylindrical and the blowtorch is rotated or oscillated back cavity, is removably threaded over .the outside and forth by the operator. Thus, the Operator of the outer conduit 10 with the wall of the l5 rotates the flames over the forward face about conical bore 86 ,engaging the seats 18 and 19 the longitudinal axis of the hole and drives the to provide fluid-tight seals between the several scraper over the bottom face and a small portion passages 8|, 82, and 83. The tip 84 is provided of the side wall of the hole while progressively with two diametrieally opposite acetylene disadvancing the blowtorch into the mineral mass. charge ducts 81 and 88 extending from a small 20 In this way adhering particles of material are centrai bore sa to the front face of the tip in scraped from the forward face of the hole over a forwardly divergent relation to the longitudinal COIlStantly Shifting IlarrOW ZOne between the axis of the blowtorch. Two separate streams of flames extending across the whole Width of the gaseous oxygen are discharged from the tip 84, forward face. 'I'he separated material, including in converging relationship to the streams of acetboth spontaneously Spalled particles and mechanylene from the ducts 81 and 88, through two ically separated particles, then is discharged from diametrically opposite oxygen ducts 9| and 92 the hole b'y`the action of the gaseous products of extending to the front face of the tip from theI combustion and the debris-ejection fluid disannular space 93, between the two seats 18 and Charged from the passages 99 and IUI. It is evi- 19 and the conical counter bore 86. The ducts 30 dent, therefore, that clinging particles 0f ma- 9| and 92 diverge forwardly from the axis of the terial are scraped free from the mass as rapidly blowtorch at a smaller angle than do the acetas they are produced because the scraper 94 folylene ducts 81 and 88 and have their openings lows immediately behind the heating iiames as in the front face of the tip spaced at a greater the blowpipe iS rotated through a half-circle in distance from the center of the tip than are each direction.

the openings of the ducts 81 and 88, respectively. It is to be understood that the foregoing de- The two gases mix outside of the blowpipe to scription is by Way of example only, and changes form a combustible gas mixture which may be in the construction and mode of operation shown ignited to produce two intensely hot fiames which and described may be made within the scope of will not flash back into the blowtorch. the invention as dened by the claims appended.

A substantially semi-circular plate-shaped hereto.

scraper tooth 94 is.welded or otherwise secured What is claimed is:

edgewise within a diametrical slot 95 in the for- 1- A blOWtOrCh Comprising a front bOdy; Said ward end of the tip 84 between the openings of body having gas-passage means therethrough; the two sets of gas discharge passages 81, 9|, l5v said body having coolant-passage means thereand 88, 92. The scraper 94 thus projects for-r through; conduits communicating with said gaswardly from the tip 84, and also is of such size passage means and said coolant-passage means; that it projects laterally from the tip to provide a tip removably engaged over said front body; for scraping the sides of a hole as well as the said tip having passage means communicating bottom face. 'Ihe arcuate leading edge or sur- 50 with the gas-passage means in said body and face of the scraper 94 is protected against abraadapted to discharge gas to provide a llame; at sion by a layer 90 of a hard-facing alloy of the least one scraper member carried by said tip, said cobalt-chromium-tungsten type, such as Haynes member having a passage therein; and said tip Stellite alloy. having passage means establishing communica- Two diametrically opposite ducts96 and 91 in 53 tion between the passage in said scraper member the tip 84 establish communication between an and the coolant-passage me ans in said body. annular iluid distributing passage 98, between the 2. A blowtorch comprising a front body; an adaptor body 14 and the tip B4, and two generelongated tube extending rearwardly from said ally V-shaped discharge passages 99 and |0I, refront body; said body having gas-passage means spectively, in the scraper 94. The legs |02 and co therethrough; said body having first coolant- |03, respectively, of the V-shaped passages 99 passage means therethrough communicating with and 0|, are inclined outwardly and rearwardly the interior of said tube; said body having a toward the rear end of the blowtorch with resecond coolant-passage therethrough; conduits spect to its forward end, and have openings in connected into said gas-passage means and'said the external surface of the scraper on two bev- C5 second coolant-passage and extending reareled surfaces |00 and |04, respectively, so that wardly from said body within said tube; a tip iluid may be discharged into a hole adjacent to removably engaged over said front body; said its bottom and directedtoward the mouth theretip having` passage means communicating with of for the ejection and/or the moistening of said gas-passage means in said body and adapted debris v 7c to discharge gas to provide a ilame; at least one The operation of the blowtorch shown in Figs. member carried by said tip and projecting for- 12, 13, and 14 is generally the same as that of the wardly therefrom for mechanically operating on blowtorch shown in Fig. 1. The principal advanmineral materials and the like, said member havtage of the blowtorch of Fig. 12, however, is that, ing a passage therein; said tip having coolantinasmuch as when a hole is being thermally passages establishing communication between the passage in said last-named member and the respective coolant-passages in said body; and means providing fluid-tight seals between said body and said tip to prevent leakage between passages.

3. A blowtorch comprising a front body; an elongated tube extending rearwardly from said body; said body having gas-passage means therethrough; said body having first passage means therethrough for a cooling and debrisejection uid communicating with the interior of said tube; said body" having a second passage therethrough for a cooling and debris-ejection fluid; conduits communicating with said gaspassage means and said second fluid passage and extending rearwardly from said body within Asaid;l tube; a tip removably engaged over said'front body; said tip having passage means communieating with said gas-passage means in said body and adapted to discharge gas to provide a flame; at least one member carried by said tip and projecting forwardly therefrom for mechanically operating upon mineral materials and the like,

said member having a passage; said tip having passages establishing communication between the passage in said last named member and the respective cooling and debris-ejection uid passages in said body; means providing fluid-tight seals between said body and said tip to prevent leakage between passages; and said tip having ports communicating with said first and second cooling and debris-ejection uid passages in said body, said ports being adapted to discharge fluid from said tip. l

4. A blowtorch comprising a front body; said body having passages therethrough; conduits communicating with said passages; said front body having a series of concentric annular sharpedged seats of progressively decreasing diameter toward the front of such blowtorch, each seat being disposed between two passages; and a removable tip cooperating with said front body, said tip having a recess provided with a conical wall engaging said seats to provide seals, and said tip having passages therein communicating with the passages in said body.

5. In a/blowtorch, a front body having a series of concentric annular sharp-edged seats of progressively decreasing diameter toward the front of said front body; said body having gas-passage means and two cooling-fluid passages therethrough; each of said annular seats being between two of said passages; and separate conduits communicating with said passages; said body being adapted to cooperate with a tip having passages' therein adapted to communicate with passages in said body,` said sharp-edged seats being adapted to engage such tip to provide seals.

6. A blowtorch for thermally piercing holes in minerals and the like comprising an elongated tubular member having front and rear ends, said tubular member being adapted to provide a flame adjacent to said front end; and means adjacent to said front end and projecting forwardly and laterally from said tubular member for disintegrating mineral material loosened by the flame.

7. A blowtorch for thermally piercing holes in minerals and the like comprising an elongated tubular member having front and rear ends, said tubular member being adapted to provide a llame adjacent to said front end; a pair of hollow prongs carried on the front of said tubular member; and means for bringing a cooling medium into heattransfer relation with said prongs.

8. A blowtorch for thermally piercing holes in minerals and the like comprising an elongated tubular member having front and rear ends, said tubular member being adapted to provide a flame adjacent to said front end; and a plate-shaped disintegrating device projecting edgewise from the front end of said tubular member.

9. A blowtorch as claimed in claim 8 wherein said disintegrating device is approximately semicircular in shape and is arranged approximately on a diameter of said tubular member with its arcuate edge to the front; and wherein said tubular member is adapted to provide heating flames on opposite sides of said disintegrating device.

10. A blowtorch as claimed in claim 8, wherein said disintegrating device has passages therein arranged to discharge fluid toward the rear of the blowtorch, and wherein said tubular member includes means for supplying uid to said passages.

11. A blowtorch comprising an elongated tubular member having front and rear ends, said tubular member including a tip at such front end; a plate-shaped disintegrating device projecting edgewise from the front end of said tip and approximately'bisecting the same; said tip having passages for discharging streams of a fuel gas on opposite sides of said plate-shaped device; and said tip having separate passages for discharging streams of a combustion-supporting gas on opposite sides of said plate-shaped device adjacent' to and converging toward said fuel-gas streams.

12. A process for piercing a hole of generally circular cross section in a mass of mineral material and the like of the type wherein intense heat causes separation of particles of material from the mass by spalling, but wherein some particles tend to adhere to the mass and fuse, which process 'conprises progressively and concurrently spalling off material from such a mass and leaving a hole having a mouth and a forward face applying a heating flame to such mass of suicient intensity to separate material therefrom by spalling, scraping adhering particles of material from the forward face of said hole, advancing said flame straight into said mass along the longitudinal axis of the desired hole thereby deepening said hole, and removing the separated material from the hole thus formed.

13. A blowtorch for thermally piercing holes in minerals and the like comprising an elongated tubular member having front and rear ends, said tubularmeinber being adapted to provide a flame adjacent to said front end; and a scraper projecting ahead of said front end for scraping the forward face 0f such hole, the leading surface of said scraper comprising a layer of a hard abrasion resistant material.

14. A blowtorch for thermally piercing holes in minerals and the like comprising an elongated tubular member having front and rear ends, said tubular member having passages for separately discharging therefrom fuel gas and combustion supporting gas to mix together outside of said tubular member and provide on ignition a llame of the diffusion type; and scraper means carried by said tubular member and extending ahead of said front end for scraping the forward face of a hole being pierced.

i5. A process for thermally working a mass of mineral material or the like of the type wherein intense heat causes separation of particles of material from the mass by spalling, but wherein some particles tend to adhere to the mass ,and fuse, comprising spallingoff particles from such a mass solely by applying intense heat thereto of suilicient intensity to separate material'therefrom by spalling, and, concurrently with the heating operation, mechanically separating adhering particles of material from the mass,

16. A blowtorch for thermally piercing holes in minerals and the like comprising an elongated tubular member having front and rear ends, said tubular member being adapted to provide a ame adjacent to said front end; and means adjacent to said front end and projectingl forwardly from said tubular member for disintegrating mineral material loosened by the flame.

17. A blowtorch for thermally piercing holes in minerals and the like comprising an elongated tubular member having front and rearvends, said tubular member being adapted to provide'a fiame adjacent to said front end, said tubular member including a tip removable and replaceable at will, said tip having tooth means projecting therefrom constructed and arranged for disintegrating mineral material loosened by such flame.

18. A process of thermally producing holes in masses of mineral materials and the like oi the type wherein intense heat causes separation of particles or material from the mass by spalling,

but wherein some particles tend to adhere to the mass and fuse, comprising spelling off material from such a mass and leaving a hole by applying intense heat thereto of suiiicient intensity to separate material therefrom by spalling; concurrently with the heating operation mechanically separating adhering particles of material from the mass; and removing the separated material from the hole thus formed.

19. A process of piercing a hole in a mass of mineral material and the like, of the type wherein intense heat causes separation of particles of material from the mass by spalling, but wherein some particles tend to adhere to the mass and fuse, comprising applying to the forward face of such hole two flames of suiilcient intensity to separate material from the mass; rotating such llames over such forward face about the longitudinal axis of such hole; concurrently scraping adhering particles of material from such face over a constantly shifting narrow zone between such ames extending across the whole width of such forward face; and removing the separated material from the hole.

' CHARLES J. BURCH.

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