US2510227A

US2510227A - Blowpipe

Info

Publication number: US2510227A
Application number: US748033A
Authority: US
Inventors: Wilgot J Jacobsson
Original assignee: Linde Air Products Co
Current assignee: Linde Air Products Co
Priority date: 1940-03-02
Filing date: 1947-05-14
Publication date: 1950-06-06
Anticipated expiration: 1967-06-06

Description

W. J. JACOBSSON June 6, 1950 I BLOWPIPE Original Filed March 2, 1940 INVENTOR Wl LGOT J. JACOBSSON ATTORNEY Patented June 6, 1950 BLOW PIPE Wilgo't J. Jac'ol sson, Plainfield, N. :I.,'assignorto The Linde Air Products Company, a corporationof Ghio Original application March 2, 1940, Serial No. 321,817, now PatentNo. 2,442,414, Halted June 1,1948. Divided and this application May T4,

1947;SerialNo. 748,033

,Glaims.

invention relates to blow-pipes and aparticlularly to improved blovcpipe headsand amethod of making the same.

This applicationis a divisionof mycopending application-Serial5N0. 321,817 filed March 2, .1940, now Patent No. 2,442,414.

Hand-deseaming blowpipes are used :for thermochemicaliy rem'oving:defectivesurface portions of steel ingotsg'billets, blooms and'the like which, unless removed, cause imperfectlons or blemishes inthe-finished rolled product. When deseaming steel 'arti'clespatleast a portion of the :WOlk surface is preheated to the oxygen ignition ltemperature and a relatively voluminous :oxidizing :gaS jet is applied obliquely against and along successive portions of the metal surface so preheated "to react thermochemically withandrernovemetal from said surface. Hand-deseaming blowpip'es employed for this zpurpose include a nozzle having a-relatively large centralcutting-oxygenpassage extending therethrough and having a 'plural'ity of relatively small preheating gas passages substantially parallel with and 'usually disposed circumferentiall-y about the cutting oxygen passage. The blowpipe is held-so :tliat the lon gitudinal axis of the nozzle is :at 'an acute angle to the surface of the workpiece and the iblowpine pushed along the workpiece in the general direction of 'the oxidizing gas stream issuing from -the nozzle. Guidanceof the blowpipel'by slidingly contacting thenozzle-end with the metal'surface is desirable when 'hancloperated .deseaming blowpipesare moved-along the surface to be deseam'ed 'as the nozzle and the jets discharging therefrom may then be more readily maintainedconstantly at the correct acute angle with the surface of the workpiece.

A blowpipe head is subject to damage by heat, oxidation, abrasion, and fromothersourceswhi'ch shorten the useful life of the blovrpipe. The life of a'hand-deseaming blowpipe particularly :isrlatively short as the blowpipe head is close to or in actual "sliding contact with the heated Work surface in a zone of high temperature "heat and oxidizing gas. 'In addition, the life of such'blowpipes isshortened further by operators using the 'bloWp'ipe head as a scraper to remove fins and other deposits from the worksurf a'ce by briskly rubbing the head back'and for th across the Work.

Accordingly, an "object of this invention is to provide a blowpipeihea'dhavinganouter protecting :and reinforc'ingllayer or :shield of abrasionandheat resistant metal to increase the useful "life :of the blowp'ipe.

Other-objects -of this inve'ntion include :the provision -:of :a iblowpipe head that is light :in Weight -.to reduce the effort involved in manipulating the blowpipe; and "the "provision of a blowpipe head that is essentially :of :a 'unitary construction and economical to manufacture.

The above-andpth'er ObjQCtS aIIdlIIQVEI features .of this invention will becom'e apparent .from the following specification and the accompanying drawing, v in which;

Fig. l isJa longitudinal sectional View of ablowpipe :head showing :one embodiment 0f the in- 'vention;

in'United-Stat'es PatentlNo. 1,957,351Ito SamueLR.

Oldham, May 1-1 1934. The head H :is adapted to operatively receive a ideseaming'nozzle N, which is removabl y retained in the head by anut T. :A

gas passage P is "formed in the :head H, and :has

smooth, continuous Wall's an'd is :so curved that it does/not "abruptly change the direction of {gas flow. Partially encircling the head H is a iprD- tecting metal layer or shield S :of a: suitable alloy, such as an alloy consisting of 35 per cent 10f metal from the group consisting of chromium,

molybdenum, and tungsten, "the remainder :principally comprising metal from the "group consist- 'ing of iron, nickel, and cobalt, which :alloy 'is resistant to abrasion, deformation and oxidation at high temperatures.

Prior to casting the 'body portion H] of head H, a properly shaped core :of a suitable material or a treated core such as a core coated with graphite, or other finely-divided material, may

be placed in the mold to form the passage H having a smooth, continuous curved wall which is not rough as is the surface of the usual sand casting.

It is preferable, but not necessary, that the cored passage ll extend entirely through the casting. The inlet end of passage II is enlarged at l3 to receive an end portion of the blowpipe cutting oxygen suppl tube 14, which is secured thereto by silver solder or other suitable means. The outlet end of passage H is enlarged to provide a socket l5, to operatively receive the inlet end of the deseaming nozzle N. Seating surfaces [6 and l! are provided in socket l5 which are engaged by corresponding seats on the rear end of the nozzle N. Nozzle N is removably secured to the blowpipe head by means of the nut T which threadedly engages the internally threaded portion H] of the socket 15. The inner end of nut T engages the underside of a shoulder E8 on the nozzle to retain the nozzle in the socket, and to tightly press the seats on the nozzle against the surfaces I6 and I7 to hermetically seal these joints.

The body III also contains a combustible gas passage communicating with cavity 2| and adapted to receive the end of combustible gas conveying tube 22 which may be fastened therein by silver solder or other suitable means. Passage 2D has an outlet orifice discharging into a chamber 23 between the seating surfaces l6 and Il.

In nozzle N there are a plurality of preheating gas passages 25 usually disposed substantially parallel to the central cuttin oxygen bore 26. The preheating gas passages 25 have inlet orifices 2'! opening into the chamber 23. The seating surface It and the corresponding seat on the nozzle form a gas-tight seal to revent cutting oxygen from escaping from passage ll into chamber 23, and the seating surface I! and the corresponding nozzle seat form a gas-tight seal preventing the escape of combustible gas to the atmosphere.

The cutting oxygen is supplied to tube It through the usual control valve of the blowpipe (not shown) and flows from tube 14 through passage I l and the central bore 26 of nozzle N to the nozzle outlet orifice 28. As shown in Fig. 1,

the longitudinal axis of the nozzle bore 26 is at approximately an angle of 70 degrees to the axis of the oxygen supply tube I4, and passage H is gradually curved and has a smooth, continu ous wall.

The combustible gas mixture of oxygen and acetylene is supplied to tube 22 from an appropriate mixer in the blowpipe (not shown) and flows from tube 22 through passage 2!), distributing chamber 23 and the preheating gas passages 25 of nozzle N and against the work to provide a flame of suificient intensity to raise that portion of the surface against which the cutting oxygen impinges to the oxygen ignition temperature.

Blowpipe heads are made of corrosion-resistant, machinable cast metal, usually bronze, which is not as resistant to abrasion, corrosion, and deformation at high temperatures as some other alloys, such as those containing chromium and tungsten commonly known to the trade as Stellite. The last-mentioned abrasion-resistant type of alloy or hard-surfacing metal is so hard that it is very difiicult, if not impossible, to machine it. To manufacture economically a blowpipe head which will have a long life, a head preferably is formed of two metals or alloys,

4 i. e., a body of a corrosion-resistant relatively easily machined metal such as bronze and a protecting shield of an alloy which is relatively hard and difficult to machine but is resistant to corrosion, abrasion and deformation when subjected to high temperatures.

The improved reinforcing and protecting shield S is permanently secured to and extends around the major part of the body [6. The shield S preferably is cast onto the body Iii to provide a unitary head, as by placing the body ID in a suitable mold and pouring abrasion-resistant molten metal into a mold cavity partially encircling the body. The body [0 contains a much larger volume of metal than the shield S so that body iii acts as a chill block to aid in quickly solidifying the molten metal to form the shield S, as shown in Figs. 1 and 2.

While the cast-in-place shield S adheres to some extent to body II], the two metals do not alloy so that there is no chemical bond to rigidly hold the shield in place. Bronze melts at around 1750 degrees and the abrasion-resistant metal melts at around 2400 degrees. The comparatively large volume of metal in body H3 so quickly chills the molten metal of shield S that there is no appreciable melting of the bronze and mixing of the metals. However, it is undesirable for the molten metal to melt the bronze casting. The body IE is made light in weight and with comparatively thin walls to reduce the weight of the blowpipe and lessen the fatigue of the operator, and if the hard-surfacing metal did melt the bronze, the walls of the passages therein, particularly passage ll, might be melted through and thus ruin the head. Therefore, the shield S and head H are preferably so designed that the shield will be mechanically retained in place on body Hi to protect the head H and especially to protect that portion of the head which comes in contact with or adjacent to the surface of the workpiece. As shown in Figs. 1 and 2, the shield is generally U-shaped in cross section so that the portion corresponding to the bend of the U completely covers the front surface of the body it, while the parts corresponding to the limbs of the U extend more than halfway around body 1!], so that the shield S grips the body ID and is mechanically retained in place thereon.

To reduce further the weight of the head H, the rear portion of body it] is formed with flat side walls, as more clearly shown at l2 in Fig. 2. As an additional aid for retaining the reenforcing shield in place, a transverse hole 30 is drilled through body iii, and when the molten abrasion-resistant metal is poured about body [0, some molten metal will flow into passage 30 and fill it to form a portion or pin 3! integral with and connecting the two sides of the shield S. It is obvious that instead of filling the hole 30 with molten metal or otherwise uniting the two sides of the shield to one another and to the body 10, the sides of the shield S may be extended farther around the body l9, but this would add useless weight and increase the cost, without materially increasing the life of the blowpipe head. A rivet may be employed to unite the two sides of the shield but the integral connection is preferable.

The shield S reinforces the blowpipe head and prevents damage thereto when the head is ad- J'aoent the work in a zone of high temperature heat and oxidizing gas and also when the operator uses the head as a scraper to remove fins and other deposits from the work surface by aszimzav rubbing the head back and :forth across such surface. The shield 8 :-.may be provided with an .outwardly projecting lip or shoe 33 which may extend all .or ;.part 'way .around :the lower end: of -.the head adjacent the .nomle socket. The shoe 33 may ,be .used .as .a,-;scraper.in removing finsaorother surface .deposits and, since -itis 10f wear-resistant metal and considerably thicker than the rest-of the shield S, the life of the blowpipe head will be furtherprolongedby this shoe.

The nozzle N preferably is provided .withan abrasion-resistant metal ring v34 .permanently secured to and projecting outwardly from the front end of the nozzle, forucontacting the work surface .to aid in guiding and positioning the nozzle. The thickness .or .height of both the shoe 33 and the ring 34 may be so proportioned and located that when the ,operatorplaces the blowpipe on the work with shoe 33 andring 34 contacting the work surface, the longitudinal axiszof the oxygen passage 26 of nozzle N is at thecorrect acute angle to the worksurface for mostefiiciently removing metal. Byhaving two points contacting the worksurface, the operator canmore readily maintain the .blowpipe in the correctposition while moving it along the surface. If nozzle N is not formed with aprotecting ring .the front end of the nozzle will be quickly worn'away, thereby ruining the nozzle and causing .the-blowpipe to be incorrectly positioned. By forming the ring 34 and the shield S of abrasionresistant material the life of the blow-pipe is greatly increased, and by correctly proportioning the; shoe 33 and ring 34 the period during which the blowpipe can be correctly positioned by contacting both the shoe 33 and ring 3:5 with the surface is greatly increased.

-Referringmore particularly to Fig. 3 .of the drawings, prior to casting the body ii], a tube 35, which may be of suitable metal such as cop- Denis placed in the mold and the moldis then filled with molten bronze or other relatively machinable corrosion-resistant metal. The tube 35 may extend through and projectbeyond both the rear and front ends of the body casting H), as

shown by broken lines at 3t and at 37. "The projectingend 36 of tube 35-is then severed and a portionof tube til-and casting i is removed by dri1lingto-form a cavity 38 into which=there ls gas-tightlysecured the end of theoxygen supply=tube l-4 asby silver solder. The other projecting end portion 3? of tube 35 maybe removed and a cavity 39 bored in bodyli! for operatively receiving a' blowpipe nozzle'N.

The tube35-has the proper diameter and preferably is gradually and smoothly curved, as shown, beforebeing placed in the mold so that theresulting cutting oxygen passage iil formed inflthev head by the tube will havesmooth, continuous-Walls and is so curved .that .-it will not abruptlyichange thedirection ofgas .flow. The oxidizing-gas flows from tube l4 .throughpassage 4ilz-to the oxygen bore/.26 extending through nozzle N and the turbulence, friction and loss of. velocity isreduced .to.-a minimum.

:Except for the means of forming passage 40, the head otFig. 3 .is generally similar to that of- Fig. 1.

.pReferring to .Figs. 4 and .of the drawings, when the body 4| is. cast, two smoothsurface cores: are vplacedin :the body mold to .form the cutting oxygen and combustible gaspassages 42 and 4-3,;respectively. In this blowpipe head the position :of the blowpipe tubes is such that the outtingnxygen tube I4 is below the combustible gas :tube .22. The core for forming cuttingoxygen-passage 42iis formed with .a'gradual reverse curveto bring theoutletportion of .passage 42 substantially axially in line with the cutting-oxygen bore 26 in the blowpipe nozzle. The'inlet-endo'i passage 42 isenlarged at' ldfor receiving 'thesend of the cutting oxygen supply tube 14 which is fastened therein, as by silver solder. :The outlet end it of passage .42 is enlarged and adapted for operatively:receivingthe rear end of a blowpipe nozzle N.

The cutting oxygen flows-from tube [4, through gradually curved passage 52, through the central bore 26 of nozzle N and out the outlet orifice 2'28 onto the work. Passage d2 has a smooth, continuouswalland is gradually curved so that the oxygen stream :does not become turbulent which wouldreduce the cutting efficiency 0f the jet.

When body 4! is cast, a second smooth-surface core is placed in the mold to form the graduallycurved combustible gas passage '43. The passage 43 is formed with an oblong cross section as shown in Fig. 5, to reduce theweightof the: head E. If passage 43 were formed with a circular cross-section and with the same cross-sectional area the wall ldwould have to be thicker which would increase the weight of the headI-I.

.The inlet end of passage 43 is enlarged as :at "iii to receive the end of the .combustiblegassupply tube 22 which is fastened in place, as by silver solder. The outlet end of passage &3 opens into the enlarged portion M of passage 43 .between the seats l6 andll. The combustible gas flows from tube 22, through passage 6.3, into the chamber '46 between the walls of .cavity h'i and the nozzle, and from chamber it through the preheating passages 25 in nozzle N. Passage 1&3 has a smooth, continuous wall and is so curved that it does not abruptly change the direction of gas flow so that no undue turbulence or friction is caused to reduce the heating efficienc of thefiames. The longitudinal axes of the cutting oxygen passage 42 and the combustible gas passage 43 are substantially in a common plane with the center of curvature of the curved portions which discharge into the inlet end of the nozzle. The combustible gas passage E3 is farther from the aforementioned center of curvature-than the oxygen passage 12 and is outside of and above the oxygen passage.

Agroove ii is formed inthe surface of body 4|, and when the molten metal forming shield S is poured about said body, the molten metal fills the groove 4'! .to forman inwardly extending lip 48. The groove 4? and lip 58, interfit so that shield S is mechanically and permanently retained on the body. The groove 6'! need not be continuous or as extensive as shown, but may comprise a plurality of short grooves or indentations, so positioned that the short lip sections will interfit therewith and hold the shield in place. A slot 49 may be formed in the shield S to reduce the weight of the head.

While I have described and illustrated different embodiments of my invention, it will be apparent to those skilled in the art that various modifications may be made without departing from the spirit and scope of the invention asset forth by the claims.

'What is claimed is:

.1. A blowpipe head comprising in combination, a body of machinable metal and thereby having relatively low wear resisting properties of gen- .erally elbow shape having at one end respective inlets v:for oxidizing and 5 fuel gasesand ati the other end a socket disposed at an oblique angle to said inlets and adapted to be coupled to a blowpipe nozzle, said body having therein respective gas passages leading from said inlets to said socket for conveying gas to said nozzle; and an abrasion-resistant shield of relatively hard metal extending over the greater part of the area of the outer surface of said elbow shaped head and secured to portions of said body for protecting and reinforcing the same.

2. A blowpipe head comprising in combination, a body of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end a socket disposed at an oblique angle to said inlets and adapted for operative connection to a blowpipe nozzle, said body having gas passages for conveying gas from said inlets through said socket to said nozzle; and an abrasion-resistant shield comprising a layer of relatively difficult to machine metal of substantially uniform thickness cast on and covering the greater portion of the outer elbow bend surface of said body between said gas inlets end and said nozzle socket end, said shield and the portion of said body in contact therewith being so shaped that said shield clings to and is permanently re tained on said body.

3. A blowpipe head comprising in combination a body of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end a socket disposed at an oblique angle to inlets and adapted to be coupled to a blowpipe nozzle, said body having therein passages for conveying gas therethrough extending from said inlets through said socket to said nozzle, at least one of said gas passages being close to a portion of the exterior elbow bend surface of said body; and an abrasion-resistant and reinforcing shield comprising a layer of hard surfacing and wear resisting metal of substantially uniform thickness secured to said body over such exterior elbow bend and gas passage adjacent surface portion between said gas inlets end and said nozzle socket end.

4. A blowpipe head comprising in combination a metal body of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end of a socket disposed at an oblique angle to said inlets and adapted to be coupled to a blowpipe nozzle, said body having therein gas passages for conveying gas from said inlets through said socket to said nozzle; an abrasion-resistant metal shield comprising a layer of hard surfacing material of substantially uniform thickness covering the greater portion of the ex terior elbow bend surface of said body between said gas inlets end and said nozzle socket end; and means extending through said body transversely to the plane of its elbow bend and connecting portions of said shield for retainin said shield on said body.

5. A blowpipe head comprising, in combination, a body of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end a socket disposed at an oblique angle to said inlets and adapted to be coupled to a blowpipe nozzle and having at least one groove formed in the outer surface thereof, said body having therein gas passages for extending therethrough from said inlets through said socket for conveying gas to said nozzle; and an abrasion-resistant shield comprising a layer of hard surfacing metal of substantially uniform thickness extending over the outer elbow bend surface of said body between said gas inlets end and said nozzle socket end thereof and extending part way around said body and having a portion projecting into said groove whereby said shield is mechanically retained on said body.

6. A blowpipe for thermochemically removing metal from the surface of metal work, comprising, in combination, a deseaming nozzle having an axial gas passage therethrough; a body of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end a socket disposed at an oblique angle to said inlets and coupled to and holding said nozzle, said body having gas passages extending therethrough from said inlets through said socket for supplying gas to said nozzle; a shield comprising a layer of relatively hard metal of substantially uniform thickness secured externally to said body and extending over the greater portion of the external elbow bend surface thereof between said gas inlet end and said nozzle socket end for protecting and reinforcing the same, said shield having an arcuate flange adjacent said nozzle socket end extending around said body transversel to the plane of said elbow bend and adapted to contact such work surface, such contacting flange extending substantially radially with respect to said axial gas passage and outwardly for a dimension greater than the maximum radius of the surface of said nozzle that when the end of said nozzle and said contacting portion are both touching said work stuface no parts of the nozzle therebetween will contact the work and the main axis of the gas passage of the nozzle will be disposed at a desired acute angle to such work surface.

7. In a deseaming blowpipe, in combination, a deseaming blowpipe head of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end a socket dis posed at an oblique angle to said inlets, said body having therein respective gas passages leading from said inlets to said socket; an external protecting shield comprising a layer of substantially uniform thickness of wear-resistant metal extending over the outer elbow bend surface of said body between said gas inlets end and said socket end; and a deseaming nozzle mounted in said socket and thereby coupled to said head and having a collar of wear-resistant metal, both said shield and said collar projecting beyond the adjacent portions of said head and all portions of said nozzle therebetween to engage the surface of metal work for correctly positioning said blowpipe relative to said surface for deseaming use and cooperating to protect against excessive wear portions of said head and said nozzle adjoining said shield and said collar.

8. For use in a blowpipe for cutting or deseaming ferrous metal, a blowpipe head of machinable metal and thereby having relatively low wear resistant qualities and being of generally elbow shape having at one end respective inlets for oxidizing and. fuel :gasesand at the other end a socket disposed at an oblique angle to said inlets, ,-7. -S@id ;bQdLhaVi Ilg therein respective gaspassages eading-fromsaidinlets to said-,socket,;one of said assages-comprising a cutting oxygen passage rovidedwith a curved portion constructed and rrangedr to gradually change the direction of xygenflow through saidahead,passage; and an brasion resistant V shield comprising a; layer of ubstantially uniformthickness; of relatively hard metal extending over the outer elbow'bend sur- 3 OLSaid bqdybetween said gas inlets end and aid socket end and secured to portions of said body for prsote,cting,. and,reinforcing the same, said shield having an external portion curved similarly to said passage in the plane of curvature i anditherebyiuniformly spaced from saidupassage. 9;. A- blowpipehead comprising in combination, a body of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end a socket disposed at an oblique angle to said inlets adapted to receive a blowpipe nozzle, said body having therein respective gas passages leading from said inlets through said socket to said nozzle, the rear portion of said body being formed with flat side walls; and an abrasion-resistant shield comprising a layer of relatively hard metal generally U-shaped in cross section so that the portion corresponding to the bend of the U covers the front elbow bend surface of the body between said gas inlets end and said nozzle socket end thereof, while the parts corresponding to the limbs of the U extend over portions of said flat side walls.

10. A blowpipe head comprising, in combination, a body of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape having at one end respective inlets for oxidizing and fuel gases and at the other end a socket disposed at an oblique angle to said inlets and adapted to receive a blowpipe nozzle, said body having therein respective gas passages leading from said inlets to said socket, the rear portion of said body being formed with flat side walls; and an abrasionresistant shield comprising a layer of relatively hard metal of substantially uniform thickness extending over the outer elbow bend of said body between said gas inlets end and said nozzle socket end and secured to said body, said shield having an outwardly projecting lip or shoe extending at least part way around the lower end of the head adjacent the nozzle socket.

, 11. For use in a blowpipe for cutting or deseaming ferrous metal, a blowpipe head of machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape and having a gas passage therein provided with an inlet portion and an outlet portion disposed at an angle to each other, said inlet portion being adapted to receive cutting oxygen and said outlet portion being adapted to receive a cutting or desearning nozzle; and an abrasion-resistant shield comprising a layer of hard surfacing metal of substantially uniform thickness cast on and covering a portion of the outer elbow bend surface of said body between said inlet and outlet portions; said gas passage, said outer surface, and shield being similarly curved to provide substantiall uniform wall thicknesses in the plane of curvature. whereby a streamlined exterior for said head and a smooth, flow for said passage are provided.

" 12: For. use in a blowpipe for cutting or deseaming a ferrous metal, a blowpipe head oi' machinable metal and thereby having relatively low wear resisting properties and being of generally elbow shape and having a cutting oxygen cutting oxygen and fuel gas respectively, and

1 said outlet portions being adapted' to receive a-cutting or deseaming nozzle,said fuel gaspassage comprising a substantially straight bore connecting' its inlet andoutlet portions; and -:an 15.:

hard surfacing 'metal of substantially uniform abrasion-resistant shield comprising a" layer of thickness cast on and covering a portion 'of the outer elbow bend surface of said body between said inlet and outlet portions; said gas passage, said outer surface, and shield being similarly curved to provide substantially uniform wall thicknesses in': the :plane of curvature,;said;shield and the portion of said body in contacttherewlth bein so shaped that said shield clings to said body; and means passing through said body between said curved and straight passages and connecting portions of said shield for permanently retaining said shield on said body.

13. In a deseaming blowpipe for removing metal from a surface of a ferrous metal body, in combination, a head formed of material having relatively low wear resisting properties and being of generally elbow shape and having fuel gas and oxygen passages extending therethrough, and the material of said head forming a wall between one of said passages and an outer surface of said head; a nozzle coupled to said head and having an oxygen passage extending longitudinally therethrough and communicating with the oxygen passage in said head; and a wearresistant shield comprising a layer of hard surfacing material of substantially uniform thickness extending over and permanently secured to said outer elbow bend surface of said head to protect and reinforce said wall; said shield and said nozzle severally having work-contacting portions extending beyond all portions of said nozzle therebetween and adapted to simultaneously contact the surface of a metal body and, when simultaneously in such contacting position, cooperating to position the outlet orifice of such nozzle oxygen passage relative to the surface of a metal body.

14. In a deseaming blowpipe for removing metal from a surface of a ferrous metal body, in combination, a head formed of material having relatively low wear resisting properties and being of generally elbow shape and having fuel gas and oxygen passages extending therethrough, and the material of said head forming a wall between one of said passages and an outer surface of said head; a nozzle coupled to said head and having an oxygen passage extending longitudinally therethrough and communicating with the oxygen passage in said head; and a wear-resistant shield comprising a layer of hard surfacing material of substantially uniform thickness extending over and permanently secured to said outer elbow bend surface of said head to protect and reinforce said wall; a wear-resistant flange on said shield and a wear-resistant flange on said nozzle extending beyond all portions of said nozzle therebetween and adapted to simultaneously contact the surface of a metal body and, when simultaneously in such contactsaid head.

11 ing position, cooperating to position the outlet orifice of such nozzle oxygen passage relative to the surface of a metal body.

15. In a deseaming blowpipe for removing metal from a surface of a ferrous metal body, in combination, a head formed of material having relatively low wear resisting properties and being of generally elbow shape and having fuel gas and oxygen passages therethrough, and the material of said head forming a wall between said oxygen passage and the outer surface of said head; a nozzle coupled to said head and having an oxygen passage extending longitudinally therethrough and communicating with the oxygen passage in said head; and a wear-resistant shield conforming to and reinforcing all of the outer surface of said wall of the oxygen passage in WILGOT J. JACOBSSON.

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

Number Number 12 UNITED STATES PATENTS Name Date Allen Sept. 29, 1885 Harris Mar. 12, 1918 Zpuck Mar. 29, 1921 Surbaugh Apr. 12, 1921 Mandeville Feb. 23, 1932 Wagner Jan. 16, 1934 Hendricks May 8, 1934 Kehl Nov. 28, 1939 Van Triest Dec. 10, 1940 Anderson Mar. 24, 1942 Egger et al Sept. 1, 1942 FOREIGN PATENTS Country Date Germany Aug. 25, 1922 Germany Dec. 3, 1937 Certificate of Correction Patent No. 2,510,227 June 6, 1950 WILGOT J. JACOBSSON It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 7, line 36, before the Word inlets insert said; line 54, after end strike out of;

and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Ofiice. Signed and sealed this 19th day of September, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'esioner of Patents.