US2288026A - Method of and apparatus for initiating metal-removing operations - Google Patents

Description

June 30, 1942. J. A. REA 2,288,026

METHOD OF AND APPARATUS FOR fNI'I'IATING A- MET AL -REMOVING OPERATION Filed May 31, 1940 JREHEAT AOETYLENE 55 gurruvc OXYGEN START/N6 T I emu/m 5 l9 TRIMMING- BLOWP/PE Y CUTTING 4 I BLOWP/PE 2/ MENTOR JOHN A. REA BY ATTORNEY.

Patented June 30, 1942 .UNlTli D STATES, PATENT OFFICE zaaaozs METHOD OF AND APPARATUS ron mrrm'r- ING METAL-REMOVING OPERATIONS m... A. Bee, Shaker Heights, ohm,- assignor to The Linde Air Products Company, a corporation of Ohio Application May 31, 1940, Serial No. 338,199

Claims.

This invention relates to metal-removing operations, and more particularly to methodsof and apparatus for heating a starting zone on a body of'-' ferrous metal to prepare such a zone for the application thereto of cutting, deseaming, or de surfacing jets of oxidizing gas.

It has been customary when performing metalremoving operations with oxidizing gas to locate the nozzle of the metal-removing blowpipe closely adjacent to the starting zone on the body of metal and to apply preheating jets of combustible gas on or adjacent to the place where the metal removing reaction is to begin inorder to heat at least a portion of such starting zone to or above the V ignition temperature. Such preheating jets may be produced by preheat orifices in the nozzle or [by nozzle means disposed adjacent to the metal removing nozzle. However, under certain circumstances it may be inexpedient to locate either the metal-removing nozzle or the preheating jets in close proximity to the starting zone; for example, where. a plurality of separate metalremoving blowpipes are intended to operate on' the metal body it may not be pfissible to locate them all adjacent to the starting zone; also where a single blowpipe is tilted with respect to the body, the position of the metal-removing blowpipe means may interfere with the progressive feeding motion of the body ofmetal. The present invention has for its purpose the provision of meanswhereby the metal-removing bloW-- be located in any desired position, even though pipe means may v at a point remotefromthe starting zone on the body of metal, and th Preheating operation is accomplished by a separate oxidizing starting jet or stream (hereinafter referred to asiet), applied against-a preheated thick ferrous metal body by a metal-removin oxidizing gas stream applied to said body at an oblique angle to an upper surface thereof and facilitating the starting of such severing operation at a starting zone adjacent the bottom portion of the forward edge of said body by heating said zone to the ignition temperature by the application of preheating means and an oxidizing gas starting jet to the upper portion of said edge surface and directing said starting jet toward the starting zone to project molten metal and slag along such zone; toprovide preheating methods and apparatus wherein a startingv blowpipe preheats thetop portion of the forward edge of a metal plate and projects a flame-cutting jet downwardly along such forward edge in the plane of the desired cut, to preheat, a starting zone at the bottom of the forward edge; and to provide methods of and apparatus for controlling the flow of gases to the respective blowpipes and for coordinating with the operation of the blowpipes the progressive movement of the metal body rela- I tive to the blowpipes.

These and other Y bjects will become more apparent'from the following description and from the accompanying drawing.

In the drawing,

' Fig. Us a perspective semirdiag rammatic view;

of afmetal-removing blowpipe apparatus incorporating principles of the present invention and showing starting, cutting, and trimming blowpipes in operative relation to a body of ferrous portion of the metal body and directed so as to provide an incandescent area or a molten puddle at the starting zone against which the metalremoving stream orjet (hereinafter referred to asstream) is applied. a

The principal objects of the present invention are to provide improved methods of and apparatus for facilitating the starting of a thermochemical metal-removing operation by preheating to the ignition temperature a starting zone on a body of ferrous metal; to provide such method of and apparatus for removing metal employing the heat of combustion of a portionof themetal with .an oxidizing starting'jet-for forming anincandescent areaat the starting zoneofthe metalremoving operation; to provide a'method of and metal; and

Figs. 2, 3, and 4, are diagrammatic views ofthe apparatus disclosed in 1, representing the relation .of the blowpipes to the metal body during successive stages of operation.

Generally speaking, the'invention comprehends facilitating the start of a metal-removing operation by projecting a starting jet of oxidizing cutting gas along a surface of a metal body so as to form in the body a substantially incandescent groove, path, or strip traversing the zone at which the metal-removing operation is to be started. The starting jet is projected from a starting blowpipe, preferably comprising a conventional cutting blowpipe having a nozzle provided with a central cutting oxygen orifice, and one or morevadjoining preheating gas-orifices.

The starting blowpipe is located with its nozzle adjacent to the body of ferrous metal at a portion substantially remote from the zone of initial application of the metal-removing stream, so that apparatus for raising to the ignition temperature I a portion of a metal body against which a metalremoving oxidizing gas stream is to be applied by preheating means positioned at a substantial dis- I tance from the initialzone of application-of the 'metal removing stream; to provide a method'of and apparatus for rapidly severing a relatively the preheating jets from the nozzle may heat the remote portion to the ignition temperature in the usual manner. The starting jet of oxidizing gas when applied to the properly preheated remote portion, forms a starting channel or groove in the surface of the ferrous metal body extending from the remote portion to the starting zone.

The starting channel is rendered substantially incandescent by the molten products of the oxidation reaction occurring between the starting jet and the narrow strip of the ferrous metal body removed thereby.

The improved method of starting is applicable to all forms of thermo-chemical metal-removing operations such as flame-cutting or severing, flame grooving, or desurfacing, the starting zone being quickly and efficiently heated to abov the ignition temperature by the exothermic heat liberated by the oxidizing action of the starting jet on a portion of the body operated upon.' The starting jet of oxidizing gas may be projected in any suitable direction, for example, along a vertical or horizontal surface of the body of ferrous metal, provided of course, that the groove formed by the starting jet traverses the starting zone or portion sufficiently close to the starting zone as to produce the desired preheating effect. The metal-removing stream preferably is applied directly against the molten reaction products at any point along the starting groove, or against an adjoining portion of the metal body that is heated by the molten products within the groove sufficiently to react with the metal-removing stream.

One form of apparatus embodying the invention, as disclosed in Fig. 1, comprises a body of ferrous metal M such as iron or steel mounted in any suitable manner upon conveyor rollers H having a drive shaft l2 which may be rotated in a counter-clockwise direction, as by means of a drive motor (not shown), to propel the body of metal M forwardly in the direction of the arrow during the metal-removing operation. A main metal-removing blowpipe such as a grooving, cutting, or desurfacing blowpipe C is located so as to project a metal-removing oxidizing stream l3 against successive portions of the body of metal M along the desired path of travel. For purposes of illustration, the metal-removing blowpipe is herein disclosed and described as a cutting blowpipe, adapted to form a severing kerf K in the metal body M, extending from a starting zone I 4 along the desired path as the blowpipe and body are moved relatively to one another, it being obvious that the body M could, if desired, be stationarily supported and the blowpipe moved relatively to the body by suitable means such as a cutting machine.

The starting zone I4 is heated to the ignition temperature by means of a separate oxidizing gas jet issuing from a starting blowpipe S and directed toward the, starting zone It so as to form a molten puddle at or adjacent to the starting zone as a result of an oxidation reaction effected between the flame-cutting starting jet and portions of the ferrous metal adjacent to the starting zone. The oxidizing jet projected from the starting blowpipe S may be of relatively low velocity, such as is employed in performing a deseaming or grooving operation, or of high-velocity as employed in conventional flame-cutting operations. As shown in Fig. 1 the starting blowpipe S is located so that the discharge portion of the nozzle I5 is closely adjacent to the surface against which the metal-removing stream I3 is to be applied but substantially remote from the starting zone [4. For example, where the starting zone I4 is located on a forward edge face l6 of the body M, the nozzle l5 may be located so as to project its preheating flames and starting jet against or along the same face Hi. If the starting jet is aligned with the plane of the proposed cut or kerf K it assists in preheating the body of metal M along the path to be followed by the cutting stream I 3; also, when the starting jet is thus aligned, the starting groove merges with and is included within the kerf, and therefore does not deface the work.

In the arrangement shown in Fig. 1, the cutting blowpipe C is preferably adjustably mounted with respect to the starting blowpipe S as by means of a supporting clamp l1 orother suitable supporting means capable of sustaining both blowpipes above the body M, and which permits adjusting the spacing and the angle of inclination between the respective blowpipes. The cutting blowpipe C is located so that its nozzle I8 is inclined forwardly in the direction of its travel relative to the body M. By the use of a forwardly inclined cutting stream l3 the flame-severing operation may be performed at a higher rate of speed than otherwise, as fully explained in Patent 2,184,561 dated December 26, 1939. Both blowpipes C and S are located with the discharge portions of the nozzles l5 and I8 adjacent to but slightly above the level of the top surface 19 of the body of metal M so as not to interfere with the body M as it is moved forwardly in the direction of the arrow during the cutting operation.

With the blowpipes S and C arranged as shown in Fig. 1, the zone of initial application 14 of the cutting stream I3 is located at the bottom of the forward edge surface l6, and the nozzle I8 is separated from the starting zone by such an excessive distance that the preheating jets from the nozzle I8 are of insufficient intensity to independently preheat the starting zone M to the i'gnition temperature.

The starting blowpipe S islocated apart from the blowpipe C and initially is positioned so that it may project preheating flames against the top of the edge 16, to preheat a small area or portion l0 thereof to or above the ignition temperature. The nozzle I5 is positioned to project the starting jet of oxidizing gas against the preheated top portion I0, and thence vertically downward along the edge surface IS in the plane of the desired cut, thereby forming a groove or channel 2| in the edge surface l6, along which channel are projected the molten products of the exothermic reaction between the starting jet and the vertical strip of metal removed by the starting jet. The blowpipes S and C are illustrated as being aligned in the plane of the kerf so that the channel or groove 2| traverses the starting zone l4 ciently to receive the stream l3.

The oxygen and acetylene connections to the respective blowpipes and the means employed to control the flow of gases are diagrammat cally illustrated in Fig. 1. Tubes '22 and 23 conduct fuel gas such as acetylene and a combusticnsupporting gas such as oxygen from respective sources of supply to the preheating gas mixture chambers of the blowpipes S and C. Cutting oxygen for both blowpipes S and C passes through main supply tube 24 to a two-way valve 25, operable by means of a lever 26 to connect the main cutting-oxygen supply tube 24 with either of the cutting oxygen tubes 2'! or 28. Two separate valves may be employed in place of valve 25, in the event that it is desired to have the starting jet continue briefly after the metalremoving stream is turned on. Preheating mixture valves 29 and 3| preheating oxygen and tive blowpipes.

regulate the flowof the acetylene to the respecand preheats that zone sulfitioned adjacent to the preheating flames preheat to the ignition portion v inthe plane of the desired out, and so thatt-" thestarting jet, when projected from-the: nozzle 1 .a groove of channel theforward edge toward andfinto juxtaposed relation with the starting zone i4.

' blowpipe C meanwhile is the forward edge -to'thebodyMsothat plane of the desired cut portion of preheating A 32 or similar control means is employed for actuating the means that provides relative movement betweenthe body of metal M and the cutting blowpipe 0.. The switch 32 may be provided with electrical connections adapted to open or close the circuit to the conveyor motor (not shown); lever 26 in the manner shown in Fig. 1, the operation of the conveyor motor may be suitably coordinated with the blowpipeC, as will be more fully explained.

Although a forwardly inclined cutting blow pipe may provide higher cutting speeds, the edges or sides of the kerf formed by such a blowpipe may be more irregular than those formed by a blowpipe progressing at lower velocities. -Such irregularities in the kerf wall may be corrected by means of a trimming blowpipe which follows at a distance behind the cutting blowpipe, slightly to one side of K so as to project an oxidizing trimming jet or stream against one of the irregular walls thereof. The function and operation of such a trimming jet has been fully described in Patent2,184,56l

' dated December 26, 1939. A trimming blowpipe T may be secured in spaced relation to the cutting blowpipe C in means of the supporting clamp H. The blowpipe T is supplied with preheating acetylene and oxygen by connection with and'with cutting oxygen by connection with the cutting oxygen tube to the trimming blowpipe T is controlled by a tandem-operated valve 33 which allows the blowpipe T to be rendered operable orincperable' at will.

operation of the cutting the central plane of the kerf the tubes 22 and 23,

The natureof the invention may be niore fully" by connecting the switch to the the supply tube 24.

any desired manner as by 21. The flow of all gases 7 i initiation of the flow of the stream i3. Figs. 2, 3,-

under stoo d in connection with a typical exam-j ple'of operation. In accordance with the arrangement shown in Fig. 1, a body of metal M" located upon the conveyor rollers ll forward edge It of the blowpipe C. The starting blowpipe S isposi- |5, will intercept the edge I'G sufficiently' to fo'rm extending "downwardly'along with the body facing the, cutting.

the forward edge lfiso'that from the" nozzle'limay temperature the small Ill at the top of the edge lii,.'preferably- V The cutting spaced forwardly from T [8 may project the on ting streaml3"in the path of travel, that trimming blowpipe valve lever 26'being located in a vertical posiat the-beginning of the e is, the starting zone [4. The T may be positioned as shown 9 behind the cutting blowpipe c, if desired.

gases to the blowpipes, the .6

"applied to successive ming jet of oxidizing gas I w followsalbhg the k'erf. K behind the blowpipe the bore of the-nozzle heating means from the starting zone II and from the cutting blowpipe C, are effective to quickly'preheat the portion 'll. At the moment that the arealll beneath the nozzle I! has been raised to the ignition temperature, the valve lever 26 is moved in a clockwise direction so as to connect the tube 28 with the cutting oxygen supply tube 24 thereby projecting the starting jet from the nozzle II and producing the groove or channel 2| in the edge It. The brief oxidation reaction of the starting jet heats the entire strip of metal along the channel 2| to a high temperature thereby preheating the area H to receive the severing or metal-removing stream it. Without delay, the lever 2| is shifted in a counter-clockwise direction to the position shown in Fig. 1, thereby discontinuing the starting jet and connecting the cutting-oxygen tube 21 of the blowpipe C with The stream l3 impinges on and reacts with the heated metal at the starting zone ll to start the cut. The conveyor rollers can be set in motion at the time that the cutting operation is inaugurated to move the body M forwardly, causing the stream l3 to be portions of the body along the desired line of cut. the conveyor motor switch 32 may be connected with the lever 26 so that when the lever 26 is moved to the position indicated in Fig. 1, the circuit to the conveyor motor is completed;

The arrangement shown in Fig. 1 illustrates the relation of the parts at the moment following the discontinuance of the starting jet and and 4 illustrate diagrammatically successive positlon's of the blowpipes with respect tothe work M. In Fig.2 the starting blowpipe 'S has beenrendered completely inactive by closing the preheating" mixture valves 29.- The cut meanwhile 1 has progressed upwardly and forwardly along the desiredpath, the out being maintained by i the combined heating effect of the starting jet,

the preheating jets of the cutting blowpipe C, andftlgie exothermic heat of the'cutting reaction. In 3 the. cut hasprogressed to the top surface I9 and the preheat" is supplied principally by'the preheating jets of the cutting blowpipe C which in thisposition are located adjacent to the surface l9. Ifdesired, the trimming blow- "-.pipe T may be placed in operation by manip'u I, lating the tandem-operated valve 33 which turns on the preheating and cutting gases. The trim-v from the blowpipe T C to: trim at leastone of'thewalls of the'kerf.

If the blowpipe T is located sufficiently close to the cutting blowpipe C no additional pre-'- will be required as the residual heat from the preceding operations and theheat provided by thepreheating ming blowpipe are'fordinarily sufllcient to maintain the wall a: the kerf at the ignitionte nperature to receive the trimming jet. 4 is a view similar to Fig. 3 but discloses the cutting tion to shut off the supply of cutting oxygen. e

sonable time. The preheating flames of the starting blowpipe S, though remotely positioned" starting zone ll. Obviously,

within a rea-- and trimming blowpipes in a more advanced position along the desired line of .cut asthe body M is moved by the rollers II in the direction of the. arrow. i v

Although the starting blowp pe Shas been described as preferably projecting the starting jet downwardly along the forward edge surface,

it is obvious that it may beprojected along different surfaces, for example, horizontally-along the bottom surface of the body M toward the the blowpipes S, C,

The control element oiv jets of the trimand T may be mounted so as to be moved along the desired path of travel relatively to a stationary body of metal. The invention is not limited to flame-severing or similar flame-cutting operations but is applicable generally in facilitating the start of other similar thermo-chemical reactions.

Various modifications of the herein disclosed method and apparatus may be made by those skilled in the art without departing from the principles of the invention or sacrificing its advantages.

I claim:

I. A method of initiating the oxidation reaction between a ferrous metal body and an oxidiz ing cutting gas stream adapted to be applied to successive portions of said body, said stream being inclined forwardly in the direction of travel, said method comprising projecting a flame-cutting jet along the forward end edge of said body in alignment with the cut to be fonned by said stream to form an incandescent groove along said edge; and discontinuing said jet and substantially simultaneously therewith projecting said cutting gas streamagainst said body adjacent to the zone at which said incandescent groove intersects the bottom of said forward end edge,

2. A method of flame-severing a ferrous metal body with a flame-severing stream projected from the bore of a nozzle against successive portions of said body, comprising positioning said nozzle above said body in the plane of the desired cut with the lower end of said nozzle inclined forwardly in the direction of travel of said nozzle relative to said body; spacing said nozzle from the forward end edge of said body uni-i1 said bore is aligned with a zone at the bottom of said edge; projecting'a flame-cutting jet downwardly along said forward end edge in the plane of the severing cut, whereby said jet forms an incandescent strip of metal along said edge traversing said zone; applying said flamesevering stream from said nozzle against said zone; and moving said nozzle in a generally horizontal path relative to said body along the line of the desired severing cut.

3. Method as claimed in claim 2 wherein said jet is discontinued substantially at the time said flame-severing stream is applied.

4. Flan1e-cutting apparatus comprising a flame-severing blowpipe having a nozzle adapted to project a flame-severing stream against a ferrous metal body;. means for providing relative' motion between said blowpipe and said body whereby said stream may be projected against successive portions of said body; and a flamecutting starting blowpipe having a nozzle adapted to project preheating and oxidizing cutting jets against said body, said respective blowpipes being so arranged that at the start of a starting operation said cutting blowpipe is adapted to preheat the top of said body at the forward edge thereof and to apply a cutting jet downwardly against the preheated portion and along said forward edge in the plane of the desired cut to form an incandescent starting groove in said forward edge, and said flame-severing blowpipe is spaced from said forward edge and inclined in the plane of the desired cut so as to project said severing jet against the bottom of said forward edge in the region traversed by said incandescent groove.

5. Flame-cutting apparatus as claimed in claim that the discharge portions thereof are at an elevation slightly above the top surface of said I body.

4 wherein both of said nozzles are located so 75 6. A method of starting the cuttingof a substantially horizontal ferrous metal body having a substantially vertical end face, with a downwardly directed stream of oxidizing gas inclined with respect to said face and adapted to move horizontally relatively'to said body to form a cut in a substantially vertical 'plane' passing through said end face whereby said stream initially impinges against azone at the bottom edge of said face, which method comprises causing molten material to run down said face substantiallv, in said vertical plane to start the cutting operation of said stream in said zone at the bottom edge of said face, and then advancing said stream with respect to said body so that said face is cut upwardly along the vertical path of said molten material.

7. Blowpipe apparatus comprising a substantially vertical starting blowpipe nozzle, an inclined cutting blowpipe nozzle, means supporting said nozzles with their longitudinal axes converging in a substantially vertical plane so as to intersect adjacent to the surface of a work body, and means including a two-way valve for supplying cutting oxygen to said nozzles so that said oxygen may be supplied to either one but not both of said nozzles at the same time.

8. In a method of performing a main metalremoving operation by applying a main metalremoving stream of oxidizing gas to successive portions of a surface of a ferrous metal body along a path beginning at a zone on said surface, the improvement which comprises quickly heating said zone for thermc-chemical reaction with said stream, by projecting a separate flame-cutting starting jet toward said zone along said surface from an edge of said body bordering on said surface to react exothermally with surface portions of said body, said jet thereby forming an incandescent strip extending from said edge to said zone, said incandescent strip being adapt- -ed to react with said main metal-removing stream of oxidizing gas-at said zone to start said main metal-removing operation.

9. In a method of performing a main metalrernoving operation, the improvement as set forth in claim 8 including the step of d scontinuing said starting jet substantially upon the application of said main metal-removing stream to said zone.

10. In a method of performing a main metalremoving operation by applying a main metalremoving stream of oxidizing gas to successive portions of a surface of a ferrous metal body along a path beginning at a zone on said surface, the improvement which comprises quickly heating said zone-for thermo-chemical reaction with said stream, by projecting a separate flamecutiing starting jet toward said zone along said surface from an edge of said body bordering on said surface to react exothermally with surface portions of said body, said jet thereby flamecutting in said surface an incandescent groove included within said path and extending from said edge to said zone, said incandescent groove being adapted to react with said main metal-removing stream of oxidizing gas at said zone to start said main metal-removing operation; and discontinuing said starting jet substantially upon the application of said main metal-removing stream to said zone.

JOHN A. REA.

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