US2407972A

US2407972A - Blowpipe for piercing metal bodies

Info

Publication number: US2407972A
Application number: US456572A
Authority: US
Inventors: Robert B Aitchison
Original assignee: Linde Air Products Co
Current assignee: Linde Air Products Co
Priority date: 1942-08-28
Filing date: 1942-08-28
Publication date: 1946-09-24
Anticipated expiration: 1963-09-24

Description

p 1946. R. B. AlTCHlSON BLOWPIPE FOR PIERCING METAL BODIES Filed Aug. 28, 1942 Z'Sheets-Sheet l INVENTOR Robe/Z B Az'ichzsm ATTORNEY p 1946., R, B. AITCHISON V 7 2,407,972

BLOWPIPE FOR PIERCING METAL BODIES Filed Aug. 28, 1942 ZSheets-Sheet 2 v INVENT I Roberi B. All? won ATTORNEY Patented Sept. 24, 1946 BLOWPIPE FOR PIERCING METAL BODIES Robert B. Aitchison, Staten Island, N. Y., assignor to The Linde Air Products Company, a corporation of Ohio Application August 28, 1942, Serial No. 456,572

This invention relates to a blowpipe for piercing metal bodies wherein a jet or stream of oxygen is discharged from th blowpipe to remove, by thermochemical reaction, successive portions of a metal body,and the blowpipe is inserted in the hole or kerf produced by such removal of metal. It is to be understood that the term piercing, as used hereinafter and in the appended claims, refers not only to a substantially round hole or drilling, normally only slightly larger than the blowpipe, which extends partly or completely through the body, but also to a cut or kerf extending into the body and which partly or completely severs one portion of the body from the remainder thereof. The blowpipe and. method of this invention comprise an improvement upon the apparatus known as an oxygen lance.

An oxygen lance is used for thermochemically piercing deep holes or cuts in large bodies of ferrous metal, such as billets, ladle skulls, salamanders, and the like. The oxygen lance consists of a long iron or steel pipe through which oxygen is passed while the pipe is advanced into the hole being pierced in the body of metal. Heat for thermochemical reaction is supplied by combustion of metal at the end of the lance pipe itself, sometimes augmented by the heat of an ordinary cutting blowpipe, the lance thus becoming shorter and shorter as the operation proceeds. However, with the oxygen lance, a smooth-walled, accurately controlled, and large hole suitable for precision work, such as for centering or piercing a billet, cannot ordinarily be produced. Moreover, the expensive and now scarce metal of the lance itself is lost by combustion; progressive burning of the end of the lance renders it difi'lcult for the operator to judge the progress he is making; and it is almost impossible to control the shape of a cut with the oxygen lance, as the length of pipe required for a relatively short-hole makes manipulation of the lance diflicult.

Among the objects of this invention are to provide a blowpipe for piercing or cutting ferrous metal bodies more readily, more economically, and with a greater ease of starting and maintaining the cutting or piercing operation; to provide such a blowpipe by means of which a larger, more accurately located, and smoother-walled hole can be produced; to provide such a blowpipe which is not, like the oxygen lance, consumed itself during operation; to provide such a blowpipe in which the possibility of flashbacks, which normally lead to work stoppage, is prevented; to

3 Claims. (Cl. 158-2744) provide such a blowpipe which is adequately cooled; and to provide such a blowpipe which is better adapted than previous apparatus for piercing holes through metal bodies and producing relatively deep kerfs by a severing operation, wherein the blowpipe is inserted within the hole or cut produced. Other objects and novel features of this invention will become apparent from the following description and accompanying drawings, in which:

Fig, 1 is a condensed side view of a blowpipe constructed in accordance with this invention and utilized in piercing a hole in a ferrous metal body;

Fig. 2 is a condensed longitudinal section of the blowpipe of Fig. 1, on a slightly enlarged scale;

Fig. 3 is a longitudinal section on a further enlarged scale of the nozzle end of the blowpipe of Fig. 1;

Fig. 4 is an end view of the nozzle end of the blowpipe;

Fig. 5 is a cross-section taken along line 5-5 of Fig. 3; and

Figs. 6 to 10, inclusive, are cross-sections, on an enlarged scale, takenalong lines 6-6, '|-1, 8 -8, 9-9, and Hll0, respectively, of Fig. 2.

In accordance with this invention, a ferrous metal body is pierced thermochemically by an operation wherein a jet of metal removing oxygen is directed against a portion of the body and against the bottom of a hole formed in the body by the removal of metal therefrom, the jet of metal removing oxygen being discharged from a torch which is inserted in and advanced within the hole. Heat to maintain the thermochemical metal-removing operation is supplied by intersecting jets of oxygen and fuel gas discharged separately from the nozzle to mix and burn externally of the nozzle but within the hole. Preferably, the jets of oxygen and fuel gas which produce such an externally mixed flame have a relatively high velocity, are discharged at an acute angle to each other, and are confined until substantially immediately before impact, as by being discharged through passages which intersect at a substantially common outlet.

As illustrated in Fig. 1, a blowpipe for carrying out the above method may comprise a handle H, to which is attached a long nozzle N which is considerably longer than indicated in the drawof nozzle N, a metal removing stream or jet of from a plurality of outlet passages ll disposed in; Q

a ring surrounding central tube IE1; and a plurality of oxygen jets are discharged. from outlet passages i2, each of which terminates in a substantially common outlet with one of the acetylene passages l l. The oxygen and acetylene jets discharged from these passages thus are confined before discharge until substantially immediately before intersection, and intersect at an 2 acute angle so that kinetic energy at impact causes an intimate mixing thereof, the point of impact being closely adjacent the point of exit from the nozzle.

Acetylene and oxygen outlet passages I! and i2 terminate in a beveled surface l3 forming a bell mouth in a nozzle block H, which is provided with a central aperture into which tube ii! extends. Acetylene passages ll lead from an annular distributing passage l5, 2; portion of which is' formed between block M and central tube iii and the remainder 'of which is formed between central tube iii and a surrounding tube 5%. Passages ll diverge forwardly at a slight angle from central tube Ill and the longitudinal axis of the nozzle, while outlet passages l2 converge forwardly at an acute angle toward tube It and the longitudinal axis of the nozzle. Each oxygen passage I2 is supplied by a connecting passage ll, drilled from the rear end of block I4 and conveying oxygen from an annular distributing passage lB. formed between tube i6 and an intermediate tube l9;

with a manifold 37 which forms an annular space 33 surrounding tube 19, as in Figs. 2 and '7. Manifold 3i also forms an annular space 39 about baiile 20, as in Figs. 2 and 6, to which used cooling medium returns, after flowing between tube l9 and baffle 29, past the end of baflle 2i! and then back between baifle f and outer tube at, as explained previously. From space 33, th used cooling medium is discharged through an outlet line Iii]. Oxygen lines 25 and 3B, acetylene line 2%; and cooling medium inlet line are connected to suitable sources of supply of the respective gases or liquids, while cooling medium outlet dfi'may be connected with a drain or other suitable source of disposal of the used cooling I medium.

To prevent the nozzle from becoming everheated or consumed during operation in a confined space, a cooling medium, such as water, is circulated therethrough in sufficient quantity to maintain the temperature of the nozzle below its temperature of combustion with oxygen. The cooling mediumflows toward the end of the nozzle between intermediate tube IQ and a baffle" tube 2G,,around the end of the bafiie tube, and then back between the baffie tube 29 and a relatively heavy tube 2i forming the outer wall of the nozzle. Each of tubes l9, l6, l9, and 2! are secured to block M in a fluid-tight manner, as by welding, brazing, or silver soldering.

As in Figs. 1, 2, and 10, the rear end of oxygen tube It is suitably secured, as by brazing, to a nipple 22, in turn connected to a valve block 23'. A shut-off valve within block 23 is actuated by a handle 24, and oxygen is supplied to the valve block 23 by an inlet line 25. Acetylene is supplied distributing passage is, between tubes iii and Hi, from an inlet line 26 provided with a control valve 21 and connected with a gland 28 which forms an annular space 29 about tube l0, as in Figs. 2 and 9. Heating oxygen is supplied passage it, between tubes IS and I9, from an inlet line 30 provided with a valve 3!. and connected with an intermediate glandEZ which forms an annular space 33 about tube l5, as in Figs. 2 and 8. A suitable cooling medium, such as water, is supplied by an inlet line 35, provided with a valve 36 and connected The rear end of baffle 28 may be secured to manifold El in any suitable fluid-tight manner, as by brazing. Gas-tight connections between tubes l6 and i9 and

glands

28 and 32 and manifold 31; respectively, may be secured in a suitable manner, as by packing 4% compressed by glands 28 and- 3-2, tightened by aset of bolts 33 which threadedly engage manifold 37- and pass through a boss formed on outer gland 28. In addition, suitable thread sealing material, such as litharge or the like, may assist in providing an eiTective seal between nipple Z2- and valve block 23', as well as between the nipple and gland 28;

In operation, after a flow of cooling water has been established and the cutting oxygen pressure testediwith the cutting oxygen valve open,

the preheat oxygen and acetylene are adjusted by valves 27 and 3| so that a suitable externally mixed flame is produced by the intersecting acetylene and oxygen jets discharged from the nozzle. The heating flame or flames thus produced is utilized in heating a desired spot on the work, and as soonas this spot has reached the kindling temperature, the metal-removing oxygen is turned on slightly and theblowpipe drawn back abit to widen the area of attack. A few circular motions will establish the width, and a slight back and forth or reciprocatory motion of the nozzle will cause the stream or jetofoxygen discharged from'the nozzle to remove metal and form themouth ofthe hole by thermochemical action. 'The' blowpipe' is advanced into the hole, preferably with a slight reciprocatory motion, suppl'ementa1"heat being supplied by the externally'mixed flames, which also-tend to-wash the wall of the hole and-produce a smooth bore;

The: hole may be pierced entirely through the body, or terminated at any point desired. In addition, the blowpipe maybe used to sever a relatively thick ferrousmetal body by moving: the nozzle along the'bottomof a kerf, or by making a hole and then removing successive increments starting at one side of the hole; During such operations, the nozzle will be adequately cooled by the water circulating theret-hrough, since the water passes quite close to theend of thenozzle, which is exposed to the greatest amount of heat.

In a piercing operation carried out in accordance with this invention; it is possible to produce, through a ferrous metal article; an accurate, smooth-walled hole of sufficient size so that a boring bar provided with atool may be inserted within the hole to' machine the hole to larger dimensions. Such a hole canbemade in a much shorter tim than by mechanical methods, such as drilling, and does not require the heavy'and expensive equipment utilized in other operations, such as punching. The size of the hole which can be made with a reasonable degree of accuracy with the consumable oxygen lance is about 1% to 1 inches, smaller than normal boring bars. A hole 2 to 3 inches in diameter can be made with greater accuracy by utilizing a, blowpip constructed in accordance with thi invention and having a nozzle approximately 1%,: inches in diameter. In addition, it appears possible, by increasing the size of the nozzle, to increase the diameter of the hole which can be produced with desired accuracy.

The apparatus of this invention alsohas peculiar utility in the reduction to charging size of large masses of scrap steel and iron, such as skulls, salamanders, and the like. Particularly under present conditions, when the availability of scrap is a problem of tremendous importance, any method by whichjsuch large masses of scrap can be more readily cut or broken up has considerable value. There aretwo general methods which may be used. In one method, lines of weakness are produced in the skull or salamander by cutting kerfs or holes partially through the metal, and the weakened mass is then broken with a heavy ball dropped thereon. In such operations, it is desirable to cut from the crown, or more nearly pure steel or iron side, as it i uneconomical to cut in the slag end of the skull,

since cutting proceeds relatively slowly and the slag is relatively friable and breaks easily in impact. After making four cuts or kerfs 90 degrees apart and extending laterally into the skull substantially to the center and down to the shrinkage cavity, a few blows of the ball readily break the skull into four parts. Thus, it is unnecessary to cut entirely through the skull.

Another method of operation (which should be carried out only by experienced operators) consists in drilling holes or kerfs enlarged slightly at the bottom, to accommodate dynamite or other explosive. A few well-placed kerfs and sufiicient dynamite will readily break up even the hardest of skulls. An advantage of thi invention, as compared withthe consumable oxygen lance, lies in the fact that the hole or kerf cannot be enlargeol at the bottom readily with the consumable lance, whereas the blowpipe of this invention can readily be manipulated to produce considerable enlargement.

The use of the blowpipe of this invention is less tiring and exacting upon the operator. The walls of the hole or kerf are relatively smooth and free of obstructions, so that manipulation of th nozzle is easier; the molten products of reaction are hotter and run out more freely, but at the same time less slag is produced which result in a cleaner kerf or hole; manipulation is easier because there is little danger of the nozzle freezing or welding itself in the hole; and a hole or kerf can be stopped at any time and restarted without difiiculty.

In addition, the end of the apparatus is not always being consumed, so that the operator can ascertain the progress he i making. This is particularly advantageous, since the rate of combustion or consumption of the end of a lance pipe may vary widely, as from 6 inches to inches per minute, for diiferent conditions, and the operator does not know, for instance, whether the first 12 inches of the lance pipe consumed have produced a hole 8 inches or 24 inches deep. Also, the nozzle of a blowpipe constructed in accordanc with thi invention, need be only as long as, or slightly longer than, the greatest thickness of body to be pierced; but a consumable lance pipe must be considerably longer to reach the bottom of the hole when ,thepipe is partially consumed, and it is therefore customary to utilize 10 foot or 20 foot lengths of pipe; It is obvious that a nonconsumable blowpipe having a nozzle only 3, 4 or 5 feet long, for instance, is much more, readily manipulated than a lance having a pipe 10 feet or 20 feet long.

Among other advantages of the blowpipe of this invention are the economies obtained. For instance, the invention eliminates the Waste in lance pine, due to the unusable stubs. Present normal practice is to utilize either 10 foot or 20 foot sections of pipe, but the last foot or so cannot be used because the lance is too short. In addition, operations carried out with the consumable lance are interrupted every time a piece of pipe is to be attached to the handle, whereas the blowpipe of this invention can be used continuously. Furthermore, since the blowpipe of this invention is not consumed during the operation, an amount of new steel, equivalent to that which otherwise would compose the pipe of the consumable lance, is saved.

The blowpipe of this invention utilizes less oxygen in piercing an equivalent hole, since lower oxygen pressures, resulting in lower oxygen consumptions, are adequate. For instance, on a job which normally required, with a consumable lance, to pounds per square inch gage oxygen pressure, with a non-consumable blowpipe a larger and more uniform hole was made at a greater speed at an oxygen pressure of only 65 pounds per square inch gage.

Although one embodiment of this invention has been described with particularity, it is to be understood that various changes may be made in the apparatus without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A blowpipe for thermochemically piercing a deep hole in a metal body comprisin a long nozzle having a central tube open at one end; means for supplying metal removing oxygen to the other end of said central tube; said nozzle also having a second tube surrounding said central tube in spaced relation; means for supplying fuel gas to the space between said central tube and said surrounding tube; said nozzle also having an intermediate tube surrounding said second "tube in spaced relation; means for supplying oxygen to the space between said second tube and said intermediate tube; a bafile tube surrounding said intermediate tube; means for supplying a liquid cooling medium to the space between said intermediate tube and said bafile tube; a ring-shaped nozzle block attached to one end of each of said tubes except said baffle tube, the end of said baille tube being spaced from said block; an outer tube secured to said block, whereby cooling medium will flow from said nozzle block in the space between said intermediate tube and said baille tube, then around the end of said baffle tube, and return through the space between said balile tube and said outer tube; and passages formed in said nozzle block meeting at substantially common outlets spaced about said central tube, one group of passages connecting with the fuel gas supply space between said central tube and said second tube and another group of passages connecting with the oxygen supply space between said second tube and said intermediate tube.

2. A blowpipe for thermochemically piercing a deep hole in a metal body as defined in claim 1, in which at least the discharge section of said 7 '7 fuel gas passages are inclined forwardly at an angle away from the longitudinal axis of said nozzle, and at least the discharge section of said oxygen passages are inclined forwardly at an angle toward the longitudinal axis of said nozzle.

3. A blowpipe for thermochemically piercing deep holes in metal bodies, comprising a long nozzle having a longitudinal, central passage for discharging axially from one end of the nozzle ametal removingstream of oxygen against a desired portion of a metal body; passages terminatingin outlets for dischargingjets of fuel gas and oxygen, each jet of fuel gas being discharged at an acute angle to an oxygen jet and inters'e'c'ting' said oxygen jet adjaoent to the point of exit from said nozzle, whereby said jets of fuel gas and oxygen converge and burn within a hole produced by thermochemical metal removal and into the mouth of which hole said nozzle is inserted, the confluent jets of fuel gas and oxygen