US2325106A - Blowpipe apparatus - Google Patents

Description

July 27, 1943. H, BUCkNAM 2,325,106

BLOWPIPE APPARATUS Filed Nov. 15, 1941 2 Sheets-Sheet 1 INVENTOR 6 i JAMES H.BUCKNAM ATTORNEY July 27, 1943. J, H, B CKNAM 2,325,106

BLOWPIPE APPARATUS 2 Sheets-Sheet 2 Filed Nov. 15, 1941 INVENTOR JAMES H. BUCKNAM ATTORNEY Patented Jul 27, 1943 I 2,325,106 BLOWPIPE APPARATUS James H. Bucknam,

Cranford, N. .L, assignor to The .Linde Air Products Company, a corporation of Ohio Application November 15, 1941, Serial No. 419,252

11 Claims.

This invention relates to the art of conditioningmetal bodies, and more particularly to apparatus for thermochemically desurfacing ferrous metal bodies such as steel bars, billets, blooms, slabs and the like, and to apparatus for thermally removing scale from such surfaces.

This application is a continuation-in-part of my pending United States patent application Serial No. 174,335, filed November 13, 1937.

During the casting .of steel ingots and the rolling of steel shapes, defects such as scale, cracks, seams and the like, form on and in the surfaces of the semi-finished bodies. In order to reduce the number of rejections of the finished products, it is desirable to condition such semifinished bodies to remove such defects. Desurfacing machines adapted to apply one or more streams of oxidizing gas such as oxygen, and preferably preheating flames, obliquely against and along the surface of a metal body to remove thermochemically a relatively shallow layer of surface metal containing a high percentage of these defects have been used for conditioning ferrous metal bodies, and arewell known. machines, especially when adapted to condition simultaneously all of the longitudinal surfaces of a metal body, have been adapted to condition or desurface bodies of the same cross-sectional size, and have not been adapted to nor intended to be used for successively conditioning bodies of different sizes. Considerable time is lost in reconstructing such prior art machines when a change of cross-sectional size occurs in the bodies undergoing treatment. r

The present invention provides 'an improved novel desurfacing apparatus for thermochemically removing a layer of surface metal from a ferrous metal body, preferably while the body is at an elevated temperature, and moving along a roll table conveyor from one rolling operation to another, and provides apparatus adaptable vfor thermally eliminating scale from such a body. The desurfacing heads are mounted and arranged so that they will not interfere mechanically or thermally with one another when they are adjusted to the proper operative position to simul- Such path of the metal bodies, so that the units can be adjusted for desurfacing bodies of the same and/or of different sizes in the same apparatus Without interfering with one another.

It is an object of this invention to provide an improved surface conditioning apparatus for thermochemically removing a relatively shallow layer from ferrous metal bodies such as steel billets, slabs, and the like, and an improved surface conditioning apparatus for thermally conditioning the surface of a metal body; to provide such an apparatus for conditioning all of the longitudinal surfaces of a ferrous metal body at a single pass; to provide such an apparatus which is readily adjustable for simultaneously conditioning all of the longitudinal surfaces of each of a succession of metal bodies of different or of the same cross-sectional dimensions; to provide such an apparatus in which the conditioning heads are supported in staggered pairs, and are movable toward and away from the longitudinal axis of the body; and to provide such an apparatus which will be of rugged construction and be readily adjustable as required to condition in the same apparatus bodies having any one of a number of different transverse crosssectional sizes.

These and other objects and novel features of this the with the accompanying drawings, in which:

Fig. 1 is a invention will become more apparent from Fig. 2 is a front elevational view of a portion.

of the machine of Fig. 1 including a section taken along the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary view, partially in section, taken along line 3-3 of Fig. 2 and more particularly showing the valve mechanism for taneously desurface all surfaces of those metal.

bodies which have a smaller transverse crosssectional size, than the transverse cross-sectional size of the largest body capable of being desurfaced by the apparatus. As shown, the four 'desurfacing heads desirably are arranged in pairs or units and these desurfacing units are supported in a staggered arrangement i. e., these units are spaced a short distance apart along the controlling the flow desurfacing a workpiece of a different size.

Referring to the drawings, the desurfacing machine M, which embodies the principles of thepresent invention may be permanently installed in alignment with sections of a conventional roll table conveyor C, but is preferably mounted on a carriage W for transverse movement along the rails-R into and out of alignment following description taken in connection plan view of a desurfacing machine embodying the principles of the present invenof gases to the nozzles of g the desurfacing heads; and,

Fig. 4 is a fragmentary view showing the blow-- plates wish the conveyor C. The conveyor C may be of any suitable type, such as is employed insteel mills for conveying semi-finished bodies from one rolling operation to another. Each section of the roll table includes a plurality of rollers, and each roller is mounted on a shaft or trunnions 2|, which is connected through suitable bevel gearing 22 to a drive shaft 24, which is in turn connected to a suitable drive motor, not shown. Thus, when the roll table motor or motors are energized, the ferrous metal body, such as a. billet B to be desurfaced, is longitudinally propelled along a part extending through the machine M and between the blowpipe heads.

The desurfacing machine M includes two similar desurfacing units E and F. The unit E includes a pair of similar blowpipe heads 25 and 26 and the unit F includes a pair of similar blowpipe heads 21 and 28. The blowpipe heads are similar and each head includes a row of nozzles 29 and means for supplying oxidizing gas, such as oxygen, and preferably a preheating or combustible gas mixture, such as a mixture of acetylene and oxygen, to each nozzle 29. Each nozzle is adapted to discharge a relatively voluminous oxidizing gas stream, and preferably a plurality of jets of a combustible gas mixture, obliquely against a corresponding one of the longitudinal surfaces of the billet B. Th combustible gas jets upon ignition burn to form preheating flames for raising the surface metal, at least at the starting zone, to the oxygen ignition temperature and for aiding in more efliciently thermochemically removing surface'metal. The nozzles 29 are preferably so spaced that at least the outer portions of the individual oxygen streams blend so as to form a composite, substantially sheet-like stream to remove a. layer of surface metal substantially uniform in depth. The blowpipe heads may be any suitabletype, or may be the same as or similar to the blowpipe head shown in thepr'eviously referred to United States application, Serial No. 174,335.

On the carriage W there are two vertical side columns 30 and 3|. To each column there is fastened a pair of brackets 32 and one end of a. horizontal link 33 is pivotally connected to each bracket 32. The opposite end of each of the four horizontal links 33 is pivotally connected to a. relatively long link or bar 34. Thus, the bar and is always perpen- 34 can move horizontally dicular to the longitudinal axis of the billet B. Near one end of the bar 34, there are pivotally mounted a pair of tal links 35 and pivotally connected to the outer ends of'the links 35 is a carrier plate 36. A second similar but longer pair of horizontal links 31 are pivotally mounted on the bar 34 and to the outer ends of the links 31 there is pivotally connected a carrier plate 38. Thus, each of the 36 and 38 forms one side of a parallelogram linkage and is independently movable upwardly and downwardly substantially in a vertical transverse plane. The plates 36, 38 can also move horizontally in unison with the bar 34 so that each of the carrier plates 36 38 is universally movable in a substantially vertical transverse plane which is substantially perpendicular to the longitudinal axis of the billet B. The horizontal links 35 are shorter than the horizontal links 31. so that the desurfacing units E and F mounted on the carrier plates 35'and 38, are not in the same vertical transverse plane, but are in a staggered relation or spaced relatively to each other along the length of the path of the billet B.

vertically swingable horizon-.

A member 40 is horizontally slidably mounted in slideways 4| formed in carrier plate 36. A hydraulic or pneumatic cylinder 42 is connected to the slidable member 40, and piston rod 43 of cylinder 42 extends through an ear 44 on plate 36,- and has threaded thereon an adjustable collar 45 and an adjustable nut 46. Compressed similar springs 41 and 48 are confined on rod 43 by collar 45 and nut 46. A plate 49 is attached to member 40 by bolts 50 and the desurfacing heads 25 and 26 of the desurfacing unit E ar mounted on plate 49. Thus, when gas or fluid under pressure is admitted to the head end of cylinder 42 the desurfacing unit E is moved horizontally toward the right away from the billet B, and when gas or fluid under pressure is admitted to the rod end of cylinder 42, the desurfacing unit E is moved toward the left, and the blowpipe head 25 is preferably urged into engagement with the right-hand side surface of the billet B at a predetermined pressure. The springs 41- and 48 are yielding, so that the desurfacing unit E can readily move horizontally a slight amount to follow irregular or bent billets.

The desurfacing unit F is similarly mounted on member 40, which is horizontally slidably mounted on plate 38. The desurfacing units E and F are independently, horizontally and vertically movable toward and away from each other and the longitudinal axis of the workpiece, such as billet B, and the longitudinal axis of the path along which the billet B is propelled.

In. the right-hand column 30, there is mounted a pneumatic cylinder 52 having a piston rod 53, the outer end-of which is connected to one end of an arm 54, pivotally mounted in the support 55, on the top of column 30. The outer end of arm 54 is connected to a turnbuckle 56, which is fastened to a cable 51 connected to the plate 36. When air or fluid under pressure is admitted to the rod end of cylinder 52, the desurfacing unit E is raised vertically toward the billet B. When the pressure is released in the rod end of cylinder 52, the unit is lowered under the influence of gravity to an inoperative position. Normally, when the unit is in the raised operative position, suflicient pressure is maintained in the rod end of cylinder 52 to urge the head 26 against the bottom surface of the billet, preferably at a predetermined pressure.

In the left-hand column 3| there is a similar pneumatic or hydraulic cylinder 52', having a piston rod 53 connected to one end of an arm 54', pivotally mounted in a supporting member 55' on top of the column. The other end of the arm 54 is connected by means of a turnbuckle 55', and a cable 51' to the plate 38. When gas or fluid under pressure is admitted to the rod end of cylinder 52', the desurfacing unit F is raised to an inoperative position away from the billet B. When the pressure in the rod end of cylinder 52' is released, the unit F is vertically lowered underthe influence of gravity to an operative position adjacent the billet B. When the unit F is lowered to the operative position, a predetermined pressure is preferably maintained in the rod end of cylinder 52' to counterbalance a portion of the weight of the desurfacing unit F, so that the head 28 is urged against the top surface of the billet at a predetermined pressure.

The previously described supporting structure is similar to the apparatus shown in the United States Patent No. 2,210,921 of H. W. Jones et al. Each desurfacing unit E and F can universally float in a substantially vertical transverse plane relative to the longitudinal axis of the workpiece, and the units are movable both vertically and horizontally toward and away from each other and the center of the workpiece. Each blowpipe head is urged into contact with the corresponding one of the longitudinal surfaces of the billet at a predetermined pressure. When the desurfacing units E and F are in the operative position, they are spaced apart along the path of the billet. The cross-section of said path is rectangular, and the edges and nozzles of the two blowpipe heads oi one unit form an L-shaped outline in one plane corresponding to two adjacent sides only of said path, Similarly the edges and nozzles of the two blowpipe heads of the other unit, form an L-shaped outline in another plane corresponding to the two oppositely related adjacent sides only of saidpath. Thus, considered together and in combination, the four blowpipe heads of the two units E and F provide a complete rectangular outline of nozzle means extending around the path of the billet.

Normally, but not necessarily, when the units E and F are moved away from the longitudinal axis of the billet} each unit is simultaneously moved both horizontally and vertically so that each unit tends to move in a direction at substantially 45 relative to a horizontal plane. When the units are urged toward the body to e desurfaced, the unit E centers itself about the lower right-hand corner 59, and the unit F centers itself about the upperleft-hand corner 60. If'

one or both of the transverse cross-sectional .dimensions of the body to be desurfaced are smaller than those of the largest body which the blowpipe heads are adapted to desurface, the

desurfacing units E and F center themselves about the corresponding corners 59 and 60 as shown in Fig. 4, so that the combined or complete outline formed'by the heads has the same transverse dimensions as the workpiece. Thus, different sizes of bodies can be desurfaced readily in the same apparatus, because all of the blowpipe heads are so constructed, arranged, and adjustable that they will not interfere with one another when allfour heads are set into operating position to condition bodies having transverse cross-sectional dimensions smaller than those bodies having the maximum transverse cross-sectional dimensions capable of being conditioned by said apparatus.

When a body, such as slab S, which is smaller in one or both transverse dimensions than the billet B is to be desurfaced, part or all of the heads will be wider than the corresponding longitudinal surfaces and the outer ends of the blowpipe heads will extend beyond the limits of the body. The effective width of each blowpipe head is substantially equal to the length of the row of nozzles in the head which discharge streams of desurfacing oxygen, and is substantially equal to the width of the composite stream formed by the idividual streams separately discharged by the nozzles. The effective widthof the heads 25 and 26 is measured from the corner 59, which is enclosed by them, nd the efiective width of the heads 21 and 2 is measured from the corner 60. Normally, the entire longitudinal surfaces are desurfaced so that the effective width of each head is also substantially equal to the surface engaging width of the head and the width of the corresponding surface. which the head desurfaces.

ends of the nozzles 29 v3 in my United States application Serial No. 174,335, of which this is a continuation-in-part, the effective width can be reduced by inserting plugs in. the recesses adapted to receive the nozzles. By means of suitable valves, instead of plugs, the eflectivewidth of each head can also be readily varied as desired.

An exemplary method of using the present invention for desurfacing,the longitudinal surfaces of a relatively smaller, rectangular slab S is illustrated in Fig. 4. The slab S has greater width than height and is shown in cross section. The

widths of its longitudinal surfaces, however, are

less than the widths of the heads 25, 26, 21, and 28, of which only the nozzle portions are shown in front elevation, the rest being broken away in the interest of clearness. The heads are shown each in contact with the corresponding one of the longitudinal surfaces. As previously described, each pair of heads of the units E and F, are supported by mechanism which permits movement thereof toward and away from the respective surfaces. The upper head 28 and the lefthand head 21 move in unison, and the lower head 26 and the right-hand head 25 move in unison.

If the heads were of the correct width to just cover or extend across each surface, the forward of all four heads might lie in the same cross-sectional plane. However, as shown in Fig. 4, when the heads are wider than the surfaces, they may be arranged so that one pair is located ahead of the other sufficiently to prevent interference with the offside portions of the other pair. In Fig. 4, the lower and righthand heads 25 and 25 are in back of the other pair. The front wall of the upper head 26 is partially broken away to show the nozzles 29. It will be seen that the width of the upper longitudinal face of slab S is fully covered by the metrical clockwise arrangement would produce.

If the desurfacing heads are of the type shown streams which issue from the left six nozzles of the upper head 28, and the nozzle opening which is offside is blanked 01f bya plug 58. The left hand head has only two nozzles in position to cover the' width of the vertical side surface, the other openings being blanked oil". The plugs 58 can be eliminated by usin the hereinafter described valving mechanism for controlling the flow of gases to the individual nozzles. The lower and right-hand heads 26 and 25 are similarly arranged. The nozzles in the upper head are directed toward the upper surface and are parallel and oriented toward the left, that is, they are' parallel to each other, and are inclined laterally toward the left side of the upper surface. The left side nozzles are oriented or inclined downward. If the lower nozzles are oriented toward the right and the right side nozzles oriented upwardly, this arrangement may be termed the symmetrical counterclockwise arrangement or orientation of the nozzles. A corresponding symsubstantially the same results. of nozzles in a blowpipe head is The orientation shown and described in the United States Patent No. 2,125,179, v

issued July 26, 1938, to E. A. Doyle.

Other arrangements to suit special conditions may also be used, such as orienting the upper and left-hand nozzles all toward the upper left corner 60, and the lower and .right-hand nozzles all toward the lower right corner 59. The latter arrangement, for example, may be used when the heads are mounted in pairs to move in unison in directions 'at 45 degrees to the faces of the body being desurfaced, for the heads may then be arranged symmetrically with the upper left and combustible gas mixture.

lower right-hand corners of the body. In Fig. 4, the upper head 28 is displaced to the right, the left head 21 upward, the right-hand head 25 downward, and the lower head 26 to the left because of the orientation of the nozzles which causes the oxygen stream to sweep laterally, the place of impingement of the streams being to one side of the point of issuance from the nozzles. The reduction of the height of the ridges between the grooves produced by each nozzle, may be obtained by closer nozzle spacing so that more smaller nozzles are used to cover a given width of surface, and by orientation of the nozzles to sweep toward one side, which orientation causes each stream to produce a wider and slightly shallower groove.

Other arrangements of nozzles in each of the heads may be used, for instance, the nozzles of any one head may be parallel and inclined toward the body to be desurfaced, but not inclined or oriented toward either side of the respective longitudinal surface. In the latter arrangement, the longitudinal axis of each nozzle is inclined toward the body and is in a plane substantially parallel to both the longitudinal axis of the body andthe direction of relative movement between the body and the heads.

As shown more particularly in Fig. 3, each desurfacing unit may include valving means V for controlling the flow of gases to the desurfacing unit, and for controlling the flow of gases to at least part of the individual nozzles 29 in each head. Thus, the effective width of each head or width of the corresponding surface. After the starting end of slab S is brought into position, gas or fluid under pressure is admitted to the head ends of cylinders 42, and simultaneously the pressure is reduced in the rod end of cylinder 52, and gas or fluid under pressure is admitted to the rod end of cylinder 52, so that each unit is simultaneously moved both vertically and horizontally toward the slab S and toward the longitudinal axis of'the path of movement of such slab, each unit centering or positioning itself about the corner 59 or 60 between the heads. The preheat gases are turned on by means of a master control valve (not shown) to the headers 62 and 63, and to the efiective nozzles of each head, and after a short pause to raise a starting zone to the oxygen ignition temperature, the desurfacing oxygen is turned on by means of a master control valve (not shown) to the header 6|, and to the effective nozzles of each head. Simultaneously the roll table motor is energized and slab S is propelled in the direction of its length and the number of efiective nozzles in each row can be readily varied in accordance with the width of the corresponding surface. The valving means for each head is similar and preferably includes three headers 6 l 62, and 63, which are connected to sources of desurfacing oxygen, acetylene and preheating oxygen, respectively. Relatively small tubes (not shown) are each connected to header 6| through a valve 64, and each tube communicates either directly or indirectly with the inlet end of the desurfacing oxygen passage of one of the nozzles 29, so that each valve 64 controls the flow of desurfacing oxygen from one'nozzle 29. Relatively small tubes (not shown) are each connected through a valve 65 or 66 to the corresponding headers 62 and 63, and each pair of these tubes are connected to a blowpipe or other suitable means, not shown, which mixes the preheating acetylene and preheating oxygen to form a Each blowpipe in turn communicates with the inlet end of one of the nozzles 29. Thus, the flow of all gases to any one of the nozzles 29 can be shut off by closing a corresponding set of valves 64, 65, and 66. If desirable, the desurfacing oxygen tube can communicate with a nozzle 29 through the blowpipe, and the valves can control the flow of gases to a pair of nozzles 29. As shown in Fig. 4, the four heads 25, 28, 21, and 28, completely encircle the body to be desurfaced, and each head is in effect moved horizontally of and parallel to the corresponding surface, and is moved toward the longitudinal axis of the body, so that its exposed width can be adjusted according to the width of the corresponding surface.

When a body, such as a billet B has been desurfaced, the desurfacing units E and F are preferably withdrawn both vertically and horizontally. If the next body to be desurfaced is smaller in one or both transverse dimensions, such as the slab S, the valves 64, 65, and 6B for each head, are correctly adjusted to vary the effective width of each head according to the along a path extending through the machine, and between the heads. If the slab S is at a high enough temperature the desurfacing may be carried out without the preheating pause. The preheating flames may be turned off after the thermochemical reaction has been started, but normally, it is desirable to leave the flames on during the desurfacing operation, to remove the surface metal more efficiently. After the slab S is desurfaced, the gases are all turned off, and the desurfacing units are both vertically and horizontally withdrawn from the operative position. If the next body is of the same size as slab S, the effective widths of the desurfacing heads need not be changed, but if the next body is of a different size, then the effective widths of all or part of the heads must be changed.

Having described my invention in detail it is obvious that alterations and substitutions can be made in the apparatus shown, and some of the features can be used without others without departing from the spirit or scope of the invention. For instance, the staggered desurfacing units could be supported and moved by other means, different types of desurfacing heads could be used, the heads could be adapted to discharge only heating flames for thermally removing scale or other defects from ferrous metal bodies, and the heads could be separately and entirely independently supported.

What is claimed is:

1. A machine for surface conditioning a metal body, the size of which is any one of a plurality of sizes, while said body is propelled along a path in the direction of its length, such machine comprising, in combination, two surface conditioning units, each of said units beng constructed to condition at least two adjacent longitudinal surfaces of said body; means supporting said units in a longitudinally spaced apart and oppositely disposed relationship adjacent said body; means for transversely moving at least one of said units toward and away from said path to vary the transverse position of at least one of said units in accordance with the size of said body.

2. A machine for surface conditioning a metal body while said body is propelled in the direction of its length, such machine comprising, in combination, two surface conditioning units, each of said units being adapted to apply gaseous streams against a corresponding pair of adjacent longitudinal surfaces of said body, each pair of surfaces having a corner portion therebetween;

- ing adapted to direct 2,325,106 -means supporting said'uni'ts in a longitudinally spaced apart and oppositely disposed relationship along said body, at least oneof said units being both horizontally and vertically mova-ble in a plane substantially perpendicular to the longitudinal axis of said body; means for urging said movable unit both horizontally and vertically against the corresponding pair of longitudinal surfaces whereby said movable unit is positioned about the corner portion between said last-mentioned surfaces.

3. Apparatus for conditioning a metal body comprising, in combination, means for supporting and longitudinally propelling such a body; two surface conditioning units, each including a pair of conditioning heads, each of said heads bea gaseous stream against a corresponding one of the longitudinal surfaces of said body; means for supporting said units adjacent said body, said units being longitudinally spaced apart relative to each other along said body; and means for moving said units toward and away from the longitudinal axis of said body in accordance with the transverse cross-sectional dimensions of said body.

4. Conditioning apparatus as claimed in claim 3, in which each of said heads includes a plurality of gas discharging nozzles inclined laterally toward a side of the corresponding longitudinal surface.

5. Conditioning apparatus as claimed in claim 3, in which each of said heads includes-a plurality of gas discharging nozzles inclined laterally toward a side of the corresponding longitudinal surface, the nozzles in the pair of heads included in each unit being oriented toward the corner of said body between the corresponding pair of longitudinal surfaces.

6. In a machine for surface conditioning a rectangular ferrous metal body of any one of a plurality of sizes, such as a steel billet or slab, the combination of two oppositely disposed conditioning units, each of said units including a pair of blowpipe heads, each pair of said heads being substantially perpendicularly disposed relative to each other and being adapted to condition two adjacent longitudinal surfaces of said body, each pair-of said adjacent surfaces having a longitudinal corner portion therebetween; means supporting said units in a longitudinally spaced relationship along said body; and means for moving said units toward and away from the longitudinal axis of said body and for urging said units into engagement with surface engaging width of heads of each of said unit in width of the corresponding tudinal surfaces of said body.

7. A surface conditioning machine as claimed in claim 6 which includes means for adjusting the effective width of each of said heads according to said surface-engaging width thereof.

8. Apparatus fordesurfacing each of a succession of rectangular ferrous metal bodies of the same or of different cross-sectional dimensions such as steel billets; slabs, and the like, such apparatus comprising, in combination,

said body to vary the. one or both of the accordance with the one of the longimeans for supporting and longitudinally propelling such a body; two desurfacing units each including blowpipe nozzle means adapted to apply in oxidizing stream obliquely against each f the twocorresponding, adjacent longitudinal :urfaces of said body; means for supporting said inits adjacent the longitudinal surfaces of said )ody; said units being longitudinally spaced apart and horizontally and along said body and, considered together and in combination, providing a complete rectangular outline of nozzle means extending around said body; and means for moving and urging each of said units toward the longitudinal axis of said body to vary the operating positions of said units in accordance with the transverse cross-sectional dimensions of said body. v

9. Apparatus for simultaneously thermochemically conditioning all four longitudinal surfaces of each of a succession of elongated ferrous metal bodies, all of such bodies being of rectangular cross-section, but some of such bodies having different transverse cross-sectional dimensions than others of such bodies, and all of such bodies being propelled in the direction of their length along a pathextending through saidapparatus, such apparatus comprising, in combination, a group of four blowpipe heads, each of said heads being constructed and arranged to deliver a thermochemical conditioning medium against a corresponding one of the four longitudinal surfaces of a body propelled along said path and between said heads; means for operatively supportingsaid heads adjacent said path and in position to conditio'n such body; and means for adjusting said heads toward and away from the longitudinal axis of said path, to vary the operating positions of said heads in accordance with the transverse cross-sectional dimensions of the body to be conditioned, two of said heads being spaced a suihcient distance along said path from the other two heads to prevent interference of any one of said four heads with any other of said four heads when said four heads are ad justed into position to condition bodies having smaller than the maximum transverse cross-sectional body dimensions capable of being conditioned by said apparatus.

10. Apparatus for thermochemically desurfacing all four longitudinal surfacesof each of a succession of elongated metal bodies during a single pass of each body through said apparatus,

said bodies being of similar transverse cross-sectional shape but some of said bodies having different transverse cross-sectional dimensions than others of said bodies and all of said bodies being propelledin the direction of their lengths along a path extending through said apparatus, such apparatus comprising, in combination, a group of four blowpipe heads, each of said heads being constructed and arranged to discharge a wide stream of desurfacing medium against a corresponding one of the longitudinal surfaces of a body propelled along said path and between said heads, the maximum width of each of such streams being sufficient to desurface the entire width of the widest longitudinal surface to be desurfaced thereby; means whereby the width of each of said streams may be decreased from such maximum width to correlate the widths of said streams to the widths. of the surfaces of bodies having smaller than the maximum transverse cross-sectional body dimensions capable of being conditioned by said apparatus; means for supporting said heads adjacent said path and in operating positions to desurface such bodies; and means for adjusting said-heads vertically toward and away from the longitudinal axis of said path, to correlate the operating positions the transverse cross-sectional dimensions of any one of the bodies of different transverse crosssectional sizes capable of being desurfaced by said apparatus, two of said heads eing spaced of said heads relatively to,

a sufficient distance along said path from the other two of said heads to prevent interference of the four heads with one another when said four heads are adjustedinto operating positions to desunface bodies having smaller than the maximum transverse cross-sectional body dimensions capable of being desurfaced by said apparatus.

11. Apparatus for conditioning all four longitudinal surfaces of each of a succession of elongated metal bodies in the course of a single pass of each body through said apparatus, said bodies being of similar transverse cross-sectional shape but some of such bodies having different transverse cross-sectional dimensions than others of such bodies, and all of such bodies being propelled in the direction of their lengths along a path extending through said apparatus, -such apparatus comprising, in combination, a group of four blowpipe heads, each of said heads being constructed and arranged to discharge a wide stream of surface conditioning medium against a corresponding one of the four longitudinal surfaces of a body propelled along said path and between said heads, the maximum width of each of such streams being suflicient to condition the entire width of the widest longitudinal surface to be conditioned thereby; means whereby the width of each of said streams may be decreased from such maximum width to correlate the widths of said streams to the widths of the surfaces of bodies having smaller than the maximum transverse cross-sectional body dimensions capable of being conditioned by said apparatus; means for operatively supporting said heads adjacentv said path and in position to condition such bodies; and means for adjusting said heads vertically and horizontally, and toward and away from the longitudinal axis of said path, to correlate the operating positions of said heads with the transverse cross-sectional dimensions of any one of the bodies of different transverse crosssectional sizes capable of being conditioned by said apparatus, said heads being so constructed and so arranged relatively to one another, that they will not interfere mechanically with one another when all four heads are adjusted by such adjusting means into operating positions, to condition bodies having smaller than the maximum transverse cross-sectional body dimensions capable of being conditioned by said apparatus.

' JAMES H. BUCKNAM.

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