US2302734A - Blowpipe nozzle - Google Patents

Description

Nbv. 24, 1942.

R. S. BABCQCK I BLOWPIPE NOZZLE Original Filed Feb. 11, 1937 FIGJ.

' INVENTOR ROGER S. BABCOCK Q. J /fTTORNM Patented Nov. 24, 1942 BLOWPIPE NOZZLE Roger S. Babcock, Plainiield, N. 1., assignor to The Linde Air Products Company, a corporation of Ohio Original application February 11, 1937, Serial No.

125,212. Divided and this application November 18, 1039, Serial No. 305,105

'15 Claims. '(01. 158-274) s This invention relates to nozzles and more particularly to nozzles adapted for use with flame-cutting blowpipes of the type shown in Patent 2,184,561 of R. S. Babcock and J. M.

Gaines, Jr., of which this application is a division.

The improved nozzle is provided with two or more juxtaposed, and preferably substantially parallel oxygen passages adjacent to the usual preheating mixture passages. The nozzle connects with the discharge end of a conventional cutting blowpipe and allows such blowpipe to perform a wide range of useful operations.

The principal objects of the present invention are: to provide an improved cutting blowpipe nozzle; to provide an improved blowpipe nozzle having a plurality of substantially parallel cutting oxygen passages; to provide a nozzle adapted to project a high-velocity cutting jet, and at least one low-velocity cutting jet to assist in preheating the work for the cutting operation; and to provide a blowpipe nozzle having a plurality of converging deseaming jet passages disposed adjacent to the cutting gas passage. These and other objects of the invention will become more readily apparent from the following description and from the accompanying drawing, in which:

Fig. 1 is a vertical sectional view through one form of the improved nozzle in operative relation to the work, showing the action of the cutting jets;

Fig. 2 is an end elevational view partly in section of the nozzle and work shown in Fig. 1;

Fig. 3 is an enlarged elevational view partly in section of a slightly modified cutting nozzle similar to that shown in Figs. 1 and 2; Fig. 4 is a transverse sectional the line 4-4 of Fig. 3;

Fig. 5 is an elevational view partly in section of a modified type of nozzle; and

Fig. 6 is an enlarged cross-sectional view taken on the line 0-6 of Fig. 5. r

The ordinary thermo-chemical cutting process consists of preheating the material to be cut, such asferrous metal to the kindling or ignition temperature and rapidly oxidizing it by means of a closely regulated Jet of oxygen. Preheating of the metal to the kindling temperature is usually accomplished by means of oxy-i'uel gas preheating flames which customarily surround the cutting jet of oxygen and vary in number and size with the composition and thickness, of the metal and the condition of its surface. It will be apparent, therefore, that the speed'of the ordinary cutting process employed upon a ferrous metal view taken on upon, and limited by, the condition of the top surface of the metal being cut and the rate at which heat can be transferred to the metal by the preheating flames.

In accordance with the present invention, independent streams or jets of oxygen are employed to eflect the preheating and cutting. The first of these streams is preferably of relatively low velocity, and may be termed a scarflng or deseaming stream or Jet since it is directed upon the surface of the metal in such a manner as to establish and maintain a reactionzone or puddle as the torch and work aremove'd relatively to one another. Furthermore, such a low-velocity oxygen jet, whiclris preferably directed upon the surface of the metal at an acute angle, will effectively remove any slag or oxide in the surface of the metal causing it to be blown forward, thereby producing a shallow preheating groove along successive portions of the line of the cut. Inaddition to the clean surface thus exposed by the low-velocity stream, considerably more heat is transferred to the adjoining metal than it is possible to transmit with the ordinary quantity of preheat available from oxy-fuel gas flames. It will be understood that more than one of these low-velocity streams may be employed, if desired, to effect a preheating of the metal to be cut. Preferably immediately behind such low-velocity oxygen stream or streams is a stream of oxygen, preferably a high-velocity cutting jet, which is directed upon and preferably of predetermined thickness, will be dependent at an acute angle to the cleaned metal surface at a point in the rearward portion of the 'reaction zone or'puddle produced by the preceding low-velocity oxygen stream or streams. This second oxygen stream, or high-velocity cutting jet, cuts through the film of molten metal and downwardly through the remaining thickness, of the workpiece. Both the high and low-velocity jets of oxygen are preferably directed in tandem upon the metal to be cut at an angle of about as shown in Fig. 1. Although it should be understood that this angle is for most purposes the optimum angle for both jets, it is not necessary for both jets to be directed at the same angle to the surface. For example, the leading lowveloeity preheating oxygen iet ma be directed upon the surface at an angle of from 10 to or at any angle which will allow it to mate a puddle; and the high-velocity stream may be directed upon the surface at an angle from 10' to which angle does not have to be the same as that for the low-velocity stream. Where it is desirable to carry the main cutting stream substantially perpendicular to the surface of the work, a reaction zone may be maintained by two low-velocity streams originating behind and on either side of the main cutting stream and intersecting directly ahead of it on the metal surface, as shown in Figs. and 6.

One form of cutting nozzle No with which the present high-speed cutting method may be practiced, comprises an elongated body 35 having tapered seating surfaces 36 and 31 at the inlet end thereof which are adapted to engage, and form gas-tight seals with similar seating surfaces in the head of a conventional blowpipe or torch. A central oxygen inlet passage or bore 38 extends longitudinally of the nozzle No, and connects with a plurality of discharge passages 4| and 43 which may be formed in the unitary body p0rti0n35 as shown in Figs. 1 and 2. In'order to adapt the nozzle No for use with discharge passages of different shape and capacity, and to simplify manufacturing procedure, the central oxygen passage or bore 38 preferably is provided at the discharge end with an insert or plug 39 which engages the bore with a press fit. As shown in Figs. 3 and 4, such a plug or insert 39 is provided with a low-velocity outlet passage extending longitudinally therethrough and having a restricted entrance portion or metering orifice 40 capable of reducing the oxygen velocity to an enlarged cylindrical discharge portion 4|. A high-velocity discharge or outlet passage is also provided in the plug and such passage preferably has a flared entrance portion 42 and a divergent or flared discharge portion 43, although the nozzle functions with a cylindrical passage used in place of the divergent portion 43. The two passages are preferably located on the same diameter of the nozzle with their axes disposed substantially in parallel relation. The construction and arrangement of the high and low-velocity discharge passages is such that when oxygen at a pressure of about 100 pounds per square inch gage, for example, is supplied to the longitudirial passage 38, a jet having a velocity of approximately 500 feet per second will issue from the discharge portion 4| of the low-velocity passage, while the jet issuing from the divergent discharge portion 43 of the high-velocity Dassage will have a velocity of substantiall 1380 feet per second.

A-pressure range of 70 to 200 pounds per square inch gage in the passage 38, with exhaust velocities up to 1600 feet per second, has been found to be the practical working range of the high-velocity passage 43, and such passages, designed for exhaust pressures of 4 to 8 pounds per square inch, are most suitable. It should be understood, however, that operation is not confined to these pressure and velocity limits since they merely represent the optimum range of working conditions. Moreover, if nozzles with cylindrical passages from 45 to 60 pounds per square inch are most satisfactory. It should also be understood that the metering orifice or constriction 40, which preferably is remote from the discharge portion, is constructed or adjusted to maintain a discharge velocity of approximately 500 feet per second in the passage 4|, although this value again only represents the optimum condition, and velocities of from 200 to 1000 feet per second may be applied.

In accordance with the usual practice employed with cutting nozzles, a plurality of heatin a similar manner are employed, pressures of the film of molten metal,

ing gas passages 44, having restricted discharge portions 45, are provided in the body portion of the nozzle. These passages are arranged in spaced relation and disposed about the oxygen passage with the discharge portions 45 inclined toward the axis of the nozzle so that the axes of the discharge portions form elements of a cone. The high-temperature heating flames produced at the discharge orifices of the passages 45 serve to heat to an ignition or kindling temperature the leading surface of the work in which a cut is to be made.

When the nozzle No is mounted for operation in a blowpipe head, with the low-velocity deseaming passage 4| arranged to precede the high-velocity passage 43 along the cutting line as shown in Fig. 1, and the blowpipe is set at an angle of about 60 to the surface of the work, said blowpipe may be operated to sever the work at high speed. Before starting such operation, the preheating flames issuing from the discharge portions 45 are utilized to heat the metal initially to the kindling temperature. Then the cutting oxygen is turned on and non-intersecting jets of oxygen are discharged from the discharge orifices of the low-velocity or deseaming passage 4| and the high-velocity passage 43, as shown diagrammatically in Fig. 1, and the blowpipe is moved relatively to the surface of the work. The low-velocity deseaming jet impinges on the surface and spreads forwardly and sidewardly slightly, producing a shallow groove 46 in the surface and forming a definite reaction zone or puddle of metal which serves as a most efficient source of preheat for the high-velocity cutting stream. Furthermore, as a result of such a deseaming operation, all scale or oxide is removed from the surface before the cutting stream reaches it. As shown in Fig. l, the high-velocity cutting stream impinges on the surface in juxtaposed relation to the low-velocity stream and at a point in the rear portion of the reaction zone produced by the deseaming stream, and due to its inherent characteristics, cuts through and downwardly through the remaining thickness of the work to form a kerf or cut 41. When cutting at top speed, the high-velocity stream is deflected backwardly to a considerable extent by the uncut metal in the kerf and results in the production of a lag which may reach as much as three inches on a bar twoinches thick.

Since the heat produced by the above described cutting operation may be great enough to cause damage to the cutting nozzle, it may be found desirable to cool said nozzle during cutting. This may be accomplished by providing a cylindrical water jacket 48 around the nozzle and near the outlet end thereof. Water may be supplied to the cooling jacket 48 through suitable conduits (not shown) from any suitable and convenient source of supply.

In the course of the cutting operation, the slag produced by the leading deseaming jet is thrown forward upon the surface of the work and .tends to accumulate at the upper edges of the kerf and adhere tightly to the surface. Since undesirable surface conditions would result if this slag were allowed to remain, jets or blasts of any compressed non-combustible gas, such as oxygen, air, nitrogen, etc., may be applied to the surfaces of the work adjacent to the freshly cut edges. Such jets are applied by means of suitable tubes 50 disposed on either side and to the rear of the cutting nozzle No, as shown in Figs. 1 and 2. These tubes are arranged to direct the blasts of noncombustible gas upon the surface substantially parallel to the cut edge and to the surface in such a manner that they wash over the surface and effectively counteract the accumulation and adherence of the slag by chilling it before it comes torest upon the surface of the work, or by forcing it away from the region of most intense heat. Similar jets may be employed on the lower side of the work also, if desired.

As previously pointed out, it is not necessary that both jets be directed at the same angle to the surface, so that while the low-velocity oxygen is directed forwardly to propagate a puddle, the main cutting stream may be directed substantially vertically, that is, at substantially 90 to the work surface. As illustrated in Figs. and 6, a modified nozzle N allows the low-velocity portion or preheating oxygen streamto be directed forwardly while the high-velocity cutting jet is projected vertically. The nozzle N' comprises a central bore 38' communicating with a source of cutting oxygen at high pressure. A high-velocity cutting-oxygen passage 43' extends from the bore 38' to the discharge end of the nozzle N. A plurality of branch passages extend from the bore 38' and terminate in metering orifices 40 located behind and on either side of the cutting-oxygen passage 43. Deseaming passages 4|, which extend from the respective metering orifices 40 to the discharge end of the.

nozzle N, are adapted to discharge low-velocity deseaming jets. The passages 4| originate behind the cutting-oxygen passage 43' on either side thereof, and extend transversely of the nozzle, or in a plane extending across the nozzle,

e. g., forwardly and downwardly in converging relation to one another so that the low-velocity streams discharged therefrom pass the high-velocity jet and intersect on the metal surface directly ahead of the main cutting jet, thereby forming a preheating puddle. One or more preheating passages may be provided to discharge a combustible mixture from the forward portion of the nozzle against the uncut portion of the metal so as to assist in the preheating. Accordingly, with the modification disclosed in Figs. 5 and 6, the nozzle N may be moved progressively over the metal body in the direction of the desired cut while projecting a cutting jet in a direction generally perpendicular to the work surface. Converging forwardly and downwardly inclined jets intersect on the metal surface directly ahead of the cutting jet and thereby heat the uncut metal to the ignition temperature.

The hereindisclosed nozzles may be modified somewhat without departing from the scope of the invention or sacrificing its advantages.

I claim:

1. A nozzle having a plurality of juxtaposed substantially parallel oxidizing gas passages therein, at least one of said passages being provided with a metering orifice for reducing the velocity of the gas discharged from such passage, at least another of said passages having flared entrance and discharge portions.

2}. A nozzle having a large central oxygen passage; and a pair of smaller oxidizing gas discharge passages communicating therewith, said nozzle being provided with a metering orifice between at least one of said discharge passages and said oxygen passage, said metering orifice being substantially narrower than the discharge orifice of the passage containing said orifice.

3. A blowpipe nozzle having a central oxygen passage extending lengthwise partly through said nozzle and adapted to connect with a source of oxygen under high pressure; a plurality of mutually adjoining smaller discharge passages extending from said central oxygen passage to the discharge end of said nozzle; and pressure reducing means in at least one of said discharge passages adapted to restrict the quantity of oxygen flowing through such discharge passage, said nozzle thereby being a'dapted to project therefrom one high-velocity jet of oxygen and at least one adjoining low-velocity jet of oxygen in non-intersecting relation with said high-velocity let.

4. A blowpipe nozzle as claimed in claim 3 wherein said pressure reducing means comprises a metering orifice axially aligned with said discharge passage.

5. A blowpipe nozzle having a relatively large central oxygen passage extending partly through the length of said nozzle; a plurality of substantially parallel discharge passages extending from said central passage to the discharge end of said nozzle, at least one of said discharge passages being provided with a metering orifice at a point remote from the discharge end of said nozzle to reduce the velocity of oxygen discharged from such passage; and a passage adapted to discharge a combustible mixture of preheating gas adjacent to said metered discharge passage.

6. A blowpipe nozzle for flame-cutting metal at a high speed, saidnozzle having a single oxygen inlet passage and two oxygen outlet passages communicating with said inlet passage and arranged to discharge non-intersecting oxygen jets in tandem relation along the cutting line on a metal workpiece, each of said outlet passages being of smaller cross-sectional area than said inlet passage; the first of said.outlet passages having a constriction adjacent its entrance of I considerably smaller cross-sectional area than the remainder of said first passage whereby the latter is adapted to discharge a low-Velocity jet of oxygen, the other of said outlet passages being constructed to discharge a jet of cutting oxygen having a velocity considerably higher than the velocity of said low-velocity jet, the discharge orifices of said outlet passages being arranged in tandem and sufficiently close together at the outlet end of said nozzle to discharge said lowvelocity jet against an area along said cutting line to produce a shallow groove immediately ahead of thepoint of impingement of the higher velocity cutting oxygen jet and thereby preheat metal along said cutting line for reaction with said higher velocity cutting jet.

'7. A metal-removing or flame-cutting nozzle having an inlet at one end adapted to communicate with a source of oxygen; a plurality of oxygen passages communicating with said inlet, each of said passages having a discharge portion extending to the outlet end of said nozzle for discharging preheating and flame-cutting jets of oxygen against a metal workpiece; at least one of said passages being provided with a constriction of substantially smaller cross section than the cross section of the discharge portion of such passage, for reducing the velocity of preheating oxygen discharged by said last-named passage.

8. A flame-cutting nozzle adapted to project mutually converging low-velocity preheating jets of oxidizing gas against a work surface to form a shallow preheating groove therein at successive portions along a path of travel, and to project a high-velocity severing jet of oxidizing gas against said work surface immediately adjacent to the point of application of said preheating jets, said nozzle comprising an inlet portion adapted to be connected with a source of oxygen under pressure; a plurality of spaced outlet passages communicating with said inlet portion, a pair of said outlet passages being mutually convergent in a plane extending across said nozzle and being provided with means for reducing the flow of oxidizing gas therethrough so as to discharge low-velocity preheating jets into mutually converging relation adjacent to said work surface, and another of said passages extending between said pair and being constructed so as to discharge a high-velocity severing jet of oxidizing gas against said work surface adjacent to the point of application of said low-velocity jets.

9. A blowpipe nozzle for flame-cutting ferrous metal, said nozzle having two oxygen passages arranged to discharge oxygen jets in tandem relation along the cutting line on a metal workpiece, the first of said passages having a constriction adjacent its entrance of considerably smaller cross-sectional area than the remainder of said first passage whereby said first passage is adapted to discharge a low-velocity jet of oxy gen, the other of said passges being contructed to discharge a jet of cutting oxygen having a velocity considerably higher than the velocity of said low-velocity jet, the discharge orifices of said passages being arranged. in tandem and being so disposed at the outlet end of said nozzle to discharge said low-velocity jet against an areaalong said cutting line to produce a shallow preheating groove immediately ahead of the point of impingement of the higher velocity cutting oxygen jet and thereby preheat metal along said cutting line for reaction with said higher velocity cutting jet.

10. A cutting nozzle adapted to project mutually converging low-velocity preheating jets of oxidizing gas against a work surface to form a shallow preheating groove along said surface, and to project a high-velocity severing jet of oxidizing gas against said work surface directly behind the point of application of said preheating jets, said nozzle having a plurality of spaced outlet passages, a pair of said outlet passages being mutually convergent in a plane extending across said nozzle and being provided with means for reducing the flow of oxidizing gas therethrough so as to discharge low-velocity preheating jets into mutually converging relation, and another of said passages extending between said pair so said nozzle and being adapted to discharge lowvelocity preheating jets into mutually converging relation on said work surface to form therein a shallow preheating groove, and another of said passages extending between said pair and being adapted to discharge a high-velocity Jet of oxidizing gas against said work surface adjacent to the point of convergence of said low-velocity jets.

12. A blowpipe nozzle having a cutting oxygen passage extending therethrough and adapted to project a jet of cutting oxygen against successive portions of the surface of a ferrous metal body; and a plurality of discharge passages communicating with said cutting oxygen passage and having means therein to reduce the flow of oxypassage in mutually converging relation in a plane extending in angular relation to the axis of said cutting oxygen passage, said converging discharge passages being adapted to project jets of low-velocity oxidizing gas againstsaid surface so as to intersect on said surface and form a shallow preheating groove therein at a point adjacent to the point of application of said jet of cutting oxygen.

13. Nozzle as claimed in claim 12 wherein each of said converging discharge passages is provided with a metering orifice.

14. A cutting nozzle having an inlet portion adapted to connect with a source of oxygen; 9. central oxygen passage extending from said inlet portion longitudinally of said nozzle and having a discharge orifice adapted to project a cutting jet of oxygen substantially perpendicularly against successive portions of the surface of a ferrous metal body; and a pair of convergent passages located in a plane extending in angular relation to said central oxygen passage, said convergent passages straddling said central passage and being adapted to project converging preheating jets into mutually intersecting relation as to discharge a high-velocity jet of oxidizing gas against said work surface adjacent to the point of convergence of said low-velocity jets.

11. A cutting nozzle adapted to project mutually converging low-velocity preheating jets of oxidizing gas against a'work surface to form a groove therein, and to project a high-velocity severing jet of oxidizing gas against said work surface in operative relation to said preheating jets, said nozzle having a plurality of spaced outlet passages, a pair of said outlet passages being mutually convergent, in a plane extending across on said surface at a point in front of said cutting jet, the angular disposition of said preheating jets being such as to cause the products of combustion from the preheating operation to move in a direction away from said cutting jet,

15. An article of manufacture consisting of a blowpipe nozzle having a main oxidizing gas passage extending to the discharge end of the nozzle and adapted to project a. metal removing stream against a work surface, said nozzle also having a plurality of preheating passages located in a plane extending transversely of said main oxidizing gas passage and extending to the discharge end of the nozzle in converging relation to one another and inclined relative to said main oxidizing passage, said preheating passages being adapted to project preheating jets into mutually converging relation against said surface at a point adjacent to but separate from the point of application on saidsurface of said metal removing stream, and in a direction diverging from said stream.

' ROGER S. BABCOCK.

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