US2444487A - Blowpipe nozzle - Google Patents

Description

Original Filed Nov. 29, 1939 INVENTOR PETER R. ARQNSON ATTORNY Patented July 6, 1948 BLOWPIPE NOZZLE Peter R. Aronson, lelham, N.

Y;, assignorto Union Carbide" and-Carbon Corporation, a corporation of New York Original application No No. 306,596, now. Pa September 4, 1945'. D tion July 1, 1944, Seria This invention relates to blowpipenozzles, and particularly to new and improved single-piece blowpipe nozzles capable of delivering a closed ringor annular preheating flame, and to a method of makingsuch nozzles. The invention has. especial utility for the production of cutting and. deseaming nozzles adapted to discharge one or' more streams of oxygento a cutting or a flame-machining zone.

In the art of metal cutting, deseaming, or

flame-machining, by the oxy-acetylene process,.

it: is often: desirable to employ an annular preheating fiame surrounding a jet of oxidizing gas being discharged from the blowpipe nozzle. Among the many advantages attributable to such an annular flame may be mentioned the following: the stability of the flame is increased; a constant preheat is supplied to the work irrespective of changes in the angular position of the nozzleabout its longitudinal axis while following an irregular line in cutting irregular shapes bymachines; a: more rapid heat transfer to the work-is secured, due to-the increased effective area of. the latter contacted by aring flame; and protection of the oxygen jet by acontinuous enclosing curtain of flame from objectionable dilution by the surrounding air.

Heretofore, multi-piece nozzles have been designed to produce ring-type flame preheating-1 However, the constructional clifllculties.

jets; encountered inaccurately positioning and com tering separate nozzle elements relative'to each other" at the discharge end of such a nozzleto form the extremely thin; accurate annular orifice required for the usual type of flame-ma:- chining operation render: it extremely difilcult' or impossible to produce by the usual machining operations successive nozzles which are identical to a degree such that they may be freely'substituted for each other in a nozzle assembly or' the like. Moreover, multi-piece nozzles possess other disadvantages. Thus, rapid deterioration of the nozzle occurs in use, due to inadequate heat transfer from the member exposed to the high temperature zone, which causeslocalover heating of the metal of that member. This appears to be due, at least in part, to the heatinsulating effect of thin layers of oxide that form at the joint between the assembled nozzle parts. Warping of the nozzle parts may occurwhen the nozzle is exposed to the heat present adjacent a cutting operation, thereby causing leakage of' gas between the parts, with resultant contamination of the oxygen stream-and rendering the nozzle ineihcient. Uncontrolled distortion of" the gas passages also may occur at.

the'forward end of the nozzle due to local overheating.

Amongthe'more important objects of this in ventiont are: to: provide." a. novel blowpipevnczzle;

vernber ,29, v1939, Serial nt No. 2,383,949, dated ivided' and this applica- 1 No. 543,061

6 Claims; (01. 158-274) curate' ring-type flame throughout the life of the nozzle; the provision ofisuch a nozzle'formed" from-a single piece. of'metal and a novel method of makingsuch nozzles involving a cold-working technique;

The above and other'objects of. the invention will; become apparent from the following specification and" drawing; in which:

Figs. Land 2 are, respectively,.a,longitudinal sectionparts being: broken away, and an end view, of one form of standard drilled or swaged nozzle to which. the principles of this invention may be-applied; I

Figs. 3 and 4, respectively, are a longitudinal sectionalevievv,zparts being broken away, and an end View, ofthe nozzle at an intermediate stage of the process Figs. 5 and- 6, respectively, are a longitudinal section, parts being broken away, and an end view, of the nozzle with the tubular mandrel in:

place, prior to a swaging operation; and

Figs. 7- and-S, respectively, are a longitudinal sectiomharts being'broken away, and an en view, of a completed nozzle. 1

Referring; tof Fig; 1, the nozzle N comprises; a

substantially cylindrical body H) of a ductile metalsuch as copper, provided with a main axial gas passage, I 2 and a series of uniformly spaced passages M respectively equidistant from the passage" hand disposed between the latter and the outer periphery of the nozzle. The rear or inlet end of the nozzle body lllis provided with a shoulder I 6- adapted to cooperate with a nut associated? with a blow-pipe for coupling the nozzle to a blowpipe. The cross-sectional area of the passage I112; obviously depends upon the typeof flame cutting or other work to be performed.

The passages-Hi usually are of relatively small cross-sectional: area, and they may be parallel with or converging. toward the main axial passage l2";

' The. nozzle N may-be formed by accurately drilling the passages l2 and I4, or'by swaginga ductile metal blank having rough oversize passages therein in which mandrels are held during the swaging process. One such swaging method is described and claimed in the RR.

. Aronson Patent No. 2,217,193, issued October 8,

In order-toproduce a? ring-type flame-of satisfactory characteristics, a nozzle having: an extremely thin annular orifice of uniformwldth is required, Such nozzle cannot be formed by any practical procedure using machinecutting tools. If the thickness of the orifice were too great, and

the torch is adjusted for the economical consump l gas consumption, thus rendering. .the gas demands of the nozzle uneconomical; or by decreasing the thickness of the annular orifice to a point where normal gas consumption and ressurewill provide a sufficiently high gas velocitytdproduce f a stable flame. Therefore, in accordance with the invention, as

illustrated in Figs. 3 and 4, the nozzle N has formed therein at its discharge end, an oversize annular. groove, recess or orifice 18 of substantial depth. The groove is concentric with the pas sa'ge l2 and is in communication with each of the passages Hi. The groove is of sufficient thickness that it can be readily machined, preferably using a milling tool commonly known as a fly-cutter." The groove I 8 includes the dischargeorifices of the-passages 14, and extends a substantial distance into'the body it.

Thenozzle thus provided with the milled g oove 18 is annealed to restore its ductility, and then is pickled and bright dipped to remove any oxide that may have formedon the nozzle during the annealing operation. A cup-shaped orv tubular mandrel 20 then is positioned within the groove IS. The internal diameter of the mandrel is such as to provide a close slidingfit on the wall forming the inner surface of groove [8. l The outer wall of the mandrel is provided with a slight draft or taper to insure easy withdrawal of the mandrel fromthe nozzle after the assembly had been subjected to a metal-working'operation. The cups'haped or tubular mandrel 20 is preferably made of spring-tempered steel; and it must :be lubricated prior to its insertion in the groove 18. The thickness of the steel forming the mandrel determines the width of the annular passage in the finished nozzle. I

The assembly of nozzle and mandrel then is fed into a swaging machine, thereby causing cold flow of the metal surrounding thelmandrel into contact with the latter so that it will conform therewith. The cold-Working should not be any greater than that sufiicient to move the outside annular layer of metal into engagement with the outer wall of the mandrel 20, otherwise the mandrel may fail due to its extreme hardness and brittleness.

- The assembly of nozzle N and the mandrel 2D is fonced into the swaging machine a'distance less than the depth of the groove l8. Thus'there is formed an annular gas-distributingchamber 22 (see Fig. 7) between the'ends of the passages 14 and the beginning of an annular passage IQ of reduced cross-section; The construction of the nozzle preferably is such that the cross-sectional area-10f at least that-p'ortion of passage l8 adjacent the discharge end of the nozzle is substantially less than the sums of-the cross-sectional areasof said passages I4, whereas the cross-sectional area of the portion of the groove l8 forming the chamber 22 adjacent the gas passages 14 is greater than the sum of the cross-sectional areas of'sald passages 14. The chamber 22 is of suflloient size to receive the gas 'fnom passages l4 and to distribute it uniformly about the periphery of the'discharge orifice or'passage- 19 without interfering with the streamline fiow of the gas within the passage 19;

The nozzles of the present invention have an-.

nular outlet orifices sufl'iciently thin to provide adequate gas velocities insuring a steady flame With an efficient utilization of the gas. The annular or ring-type flames thus produced afford a very rapid and uniform transfer of the heat to the work, while preventing or inhibiting the dilution orcontamination of the cutting oxygen with air from the surrounding atmosphere.

Upon removal of the mandrel 20, the finished "nozzle then may bekmachined to length, as by facing off the end at the swaged zone, and is then ready for use. 1 It may be annealed, pickled and bright dipped prior to or after the facing operation.

By employing a swaging or equivalent coldworking procedure for shaping and sizing the annular discharge passage in the nozzle, the surfacesdefining the passage walls have imparted thereto -ahigh degree of smoothness and hardness not securable when such passages are made by milling .or other machining operation. The swaged surfaces not only are smoother than surfaces prepared by milling, cutting, castingsand like procedures, but also are harder as aresult of the cold-working of the metal. It is Wellknown that any fabrication process which produces a soft metal-such as casting, brazing, etc.,-is unsatisfactory for the production :of cutting and deseaming nozzles and the like.

The blowpipe nozzle of the invention possesses the further important advantage of longerscrvice life, due to the fact that, because of being formed from a single piece of metal, the heat conductivity is considerably higherthan that of a nozzle foamed froma plurality of metal sections joined by brazing, or soldering. Furthermore, a onepiece blowpipc nozzle is much less subject to distortion by the heat to which it is exposed during normal use than is an assembled multi-piece nozzle.

While the various features of the improved nozzle and the novel method of making it have been illustrated in connection with the production of a nozzle designed for use in a cutting operation, it will be evident that the invention is of wide application; and that numerous details and features may be used without others, with-' The use'of a mandrel having a slight taper may have the advantagethat the resulting annu-:

lar outlet passage will converge slightly'to concentrate the flame closer to the lineof heating or cutting.

This application is a division of applicants copending application, Serial No. 306,596, filed- November 29, 1939, now Patent No. v2,383,949, issued September 4, 1945.

The invention is susceptible of modification within the scope of the appended claims.

I claim: I

1. -An integral blowpipe nozzle having an annular discharge orifice, which nozzle comprises a one-piece body made from a single piece of ductile cold-worked metal, said body having formed therein a-series of gas passages extending from the inlet end of said body to a point spaced inwardly from the discharge end thereof, said passages being disposed in an annular zone about the central longitudinal axis of said body; the discharge end of said nozzle body having formed therein an annular passage, the walls forming said annular passage having cold-Worked, hardened smooth surfaces, said annular passage communicating with each of said gas passages and forming an annular discharge outlet for said gas passages.

2. An integral blowpipe nozzle having an annular discharge orifice, which nozzle comprises a one-piece body made from a single piece of ductile cold-worked metal, said body having formed therein a series of gas passages extending from the inlet end of said body to a point spaced inwardly from the discharge end thereof, said passages being disposed in an annular zone about the central longitudinal axis of said body; the discharge end of said nozzle body having formed therein an annular passage communicating with each of said gas passages and forming an annular discharge outlet for said gas passages, the walls forming said annular passage having hardened smooth surfaces; the said body having formed therein an annular enlarged chamber intermediate said gas passages and said annular passage and in communication with each thereof; and said body also having formed therein at least one longitudinal oxygen passage extending throughout the length of said body.

3. An integral blowpipe nozzle which comprises a one-piece body made from a single piece of ductile swaged metal, the said body having formed therein a series of gas passages extending from the inlet end of said body to a point spaced inwardly from the discharge end thereof, said passages being disposed in an annular zone about the central longitudinal axis of said body; the discharge end of said nozzle body having formed therein an annular passage communicating with each of said gas passages and forming an annular discharge outlet for said gas passages, the walls forming said annular passage having hardened, smooth surfaces; said body having formed therein an annular gas-distributing chamber interposed between each of said gas passages and said annular discharge outlet, and connecting each of said gas passages with said outlet, the sum of the cross-sectional areas of said gas passages being less than the cross-sectional area. of said gas distributing chamber but greater than the cross-sectional area of the portion of said annular passage adjacent the discharge end of the nozzle.

4. An integral blowpipe nozzle having an annular discharge orifice, which nozzle comprises a one-piece body made from a single piece of ductile cold-worked copper; said body having formed therein a series of gas passages extending from the inlet end of said body to a point spaced inwardly from the discharge end thereof, said passages being disposed about the central longitudinal axis of said body; the discharge end of said body having formed therein an annular passage communicating with each of said gas passages and formin an annular discharge outlet for the latter, the walls defining the annular discharge passage having smooth hardened surfaces, the cross-sectional area of at least the portion of said annular passage adjacent the discharge end of said body being substantially less than the sum of the cross-sectional areas of said gas passages; said body having formed therein an annular chamber intermediate said series of gas passages and said annular passage and in communication with each thereof; said body also having formed therein a central longitudinal oxygen passage extending throughout the length of said body.

5. A blowpipe nozzle comprisin a unitary body of ductile cold-worked metal formed from a single piece of such metal; said body having formed therein a series of laterally-spaced gas passages extending longitudinally within said body from the inlet end of said body to a point spaced inwardly from the discharge end thereof; said body having formed therein an annular passage com-- municating with each or" said gas passages and forming an annular discharge outlet for said passages, the walls definin said annular passage having smooth hardened surfaces; the cross-sectional area of the portion of said annular passage adjacent the discharge end of the nozzle body being substantially less than the corresponding area of that portion of said annular passage adjacent said gas passages; said body also having formed therein a gas-distributing chamber interposed between said annular discharge passage and each of said gas passages, the cross-sectional area of the gas-distributing chamber being greater than the sum of the cross sectional areas of said gas passages; the said body also having formed therein a central longitudinal oxygen passage extending throughout the length of said body and having a discharge outlet encircled by said annular discharge outlet.

6. A blowpipe nozzle comprising a unitary body of ductile copper formed from a single piece of hardened cold-Worked copper; said body having formed therein a series of laterally-spaced gas passages extending longitudinall within said body from the inlet end of said nozzle body to a point spaced inwardly from the discharge end thereof; said body having formed therein an annular passage communicating with each of said gas passages and forming an annular discharge outlet for said passages, the walls defining said annular discharge passage having smooth hardened surfaces, the cross-sectional area of the portion of said annular passage adjacent the discharge end of said nozzle body being substantially less than the corresponding area of a portion of said annular passage remote from said discharge end, and being less than the sum of the crosssectional areas of said gas passages; said body also having formed therein a central longitudinal oxygen passage extending throughout the length of said body, and having a discharge orifice encircled by said annular discharge outlet.

PETER R. ARONSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,246,573 Fausek Nov. 13, 1917 1,407,306 Turpin et al. Feb. 21, 1922 1,460,662 Drager et al. July 3, 1923 1,485,033 Jenkins Feb. 26, 1924 2,192,661 Jones May 19, 1936 2,267,623 Self et al. Feb. 29, 1940 2,343,958 Crowe Mar. 14, 1944

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