US2092150A

US2092150A - Apparatus for and method of spraying molten metal

Info

Publication number: US2092150A
Application number: US756076A
Authority: US
Inventors: Purling A Bieakley
Original assignee: GILLORD CORP
Current assignee: GILLORD Corp
Priority date: 1934-12-05
Filing date: 1934-12-05
Publication date: 1937-09-07
Anticipated expiration: 1954-09-07
Also published as: NL45233C; GB466782A; FR800941A; BE412629A

Description

Q P. A. BLEAKLEY I APPARATUS FOR AND METHOD OF SPRAYING MOLTEN METAL Sept. 7, 1937.

Filed Dec. 5, 1934 4 Shets-Sheet 1- 1V, K hl/ 4 4 Sept. 7,1937. P. A. BLEAKLEY 2,092,150

APPARATUS FOR AND METHOD OF SPRAYING MOLTEN METAL.

Filed Dec. 5, 1934 4 Sheets- Sheet '2 I? (fly. 2

/ III p 1937. V P. A. BLEAKLEY 2,092,150

APPARATUS FOR AND METHOD OF SPRAYING MOLTEN METAL Filed Dec. 5, 1934 '4 Sheets-Sheet same/14 :0;

\ Sept. 7,1937." R BLEAKLEY 2,092,150

APPARATUS FOR AND METHOD Of SPRAYI NG MOLTEEN METAL Filed Dec. 1934 4 Sheets-SheetA Patented Sept. 7, 1937" APPARATUS FOR AND METHOD OF SPRAY- ING MOLTEN METAL Purling A. Bleakley, Toledo, 1 The Gillord Corporation,

poration of Delaware Ohio, assignor to Toledo, Ohio, a cor- Application December 5, 1934, Serial No. 756,076

This invention relates to metal working and more particularlyto an apparatus for spraying molten metals and the method of operation thereof, although the invention is not limited to 5 working metals but may be employed with equal facility for melting and spraying other initially solid materials.

The art of metal spraying is relatively old and the apparatus therefor well developed. This art, however, has been confined heretofore to operation upon low fusing metals. The methods and apparatus heretofore employed have not been capable of utilizing metals having high fusing points including steels and steel alloys insufficient quantities for commercial operation. Furthermore, they have necessitated extremely high gas and air pressures as well as large volume thereof for. reduction of the materials.

. In order to compete with other forms of metal working such an apparatus 'must 'be capable of depositing not less than ten to twenty pounds of material per hour with a mat texture similar to that of a fine grade of casting. For commercial operation the apparatus must be operable with a gas pressure well within that of ordinary welding operation range, that is, approximately fifteen pounds or less, and the air consumption must be materially reduced in proportion to the work accomplished. i

Heretofore high speed air turbines operating through suitable speed reduction devices have been used for feeding the material. Such motive power is not onlyextravagant in consumption of air, but is very sensitive to pressure supply fluctuations with resultant variation of the speed with which the material is fed to the flame causing incompletely fused metal to be deposited, or if fed too slowly causing the tool to become choked and the metal welded thereto.

One of the necessary factors for successful operation is that the apparatus shall be capable of working at constant air and gas pressures without necessity for frequent readjustment. -Attempts have been made here and abroad to meter the gas and air supplies, but this has only complicated the difficulties and made the fluid pressure control more sensitive than otherwise.

Another difiiculty resulting from excessive gas and air pressures and large volume consumption heretofore experienced and sought to be overcome in the present invention is that the gas and air pressures were opposed to each other, the air tending to blow out the flame and consequently it was necessary that an increased resisting 'gas 55 pressure and heat be developed at the flame point.

21 Claims. (Cl. ill-12.2)

This caused such tools to become quite hot. These conditions limited the size of the tools and limited the character of the work as well as the amount of metal which could be deposited in a given period. Such opposing high pressures. also cause the gas to back fire in the feeding nozzle, especially if the supply wire does not closely fit the opening, thereby melting the supply wire inside the feeding nozzle or causing an explosion within the tool. Making the supply wire accurately to gage, to overcome this condition, is highly expensive as it necessitates specially drawn wire with extremely low variation tolerances.

The object of the present invention is to improve the construction as well as the means and mode of operation of metal spraying apparatus whereby it may not only be economically menu: factured and operated, but will be more eflicient in use, automatic in operation, uniform in action, and unlikely to get out of repair.

l A further object of the invention is to enable the reduction and deposit of metals and alloys having relatively high fusing points.

A' further object of the invention is to provide a method and apparatus capable of depositing a large volume of metal rapidly and with a fine texture.

A further object of the invention is to provide a method and apparatus employing gas and air blasts at relatively low pressures.

A further object is to utilize the air discharge to create a suction on the gas and wire nozzle ports thereby preventing back firing and minimizing necessity for accurate wire sizing.

A further object of the invention is to provide intimate intermixture of the fuel gas and air before they reach the point of operation upon the material, and to enable uniform equalized distribution of air and gas mixture throughout the working area.

A further object of the invention is to minimize the air and gas consumption.

A further object is the provision for introduction of an additional gas into the air stream.

A further object of the invention is the maintenance of constant air and gas operating pressures with consequent avoidance of necessity for frequent readjustments.

A further obj ect of the invention is the provision of an improved nozzle construction.

A further object of the invention is to provide thermal insulation of the nozzle whereby the spray nozzle will be maintained at' a relatively low temperature during operation.

A further and highly important object of the ,separately assembled, repaired or replaced without disturbing other portions of the apparatus.

A further object is to enable convenient and "accurate machining of the nozzle, parts and render the passages readily accessible for forming and cleaning.

With the above primaryand other incidental objects in view, as will more fully appear in the specification, the invention consistsof the features of construction, the parts and combinations thereof, and the mode of operation, or their equivalents, as hereinafter described and set forth in the claims.

In the drawings, whereinis shown the preferred, but not necessarily the only embodiment .of the invention, Fig. 1 is a top plan view of the assembled apparatus. Fig. 2 is a side elevation thereof. Fig. 3 is a rear elevation thereof. Fig. 4 is a bottom plan view of the motor base, showing the air and gasconnectlons. Fig. 5 is a vertical sectional view through the base, illustrating the air and gas connections and cut-off.

Fig. 6 is a longitudinal sectional view of the nozzle assembly. Fig. 'I is a detail sectional view in a plane perpendicular to that of Fig. 6. Fig. 8 is a transverse sectional view of the nozzle assembly on line 88 of Fig. 6. Fig. 9 is a transverse sectional view of the nozzle assemblyat a midlength position on line 9-9 of Fig. 6. Fig. 10 is a transverse sectional view and front elevation of the nozzle'assembly on line |0i 0 of Fig. 6. Fig. 11 is-a detail rear view of the wire feeding rolls. Fig. 12 isan elevation of the rack and pinion adjustment of the wire lead viewed from the interior of the feeding mechanism housing. Fig. 13 is a sectional view thereof. Figs. 14, 15, and 16 are detail views of the gas, metal and air nozzles. Fig. 17 is a detail view of the gas mixing ring. Fig. 18 is a-detail view of the nozzle mounting spud and wire guide.

Like parts are indicated by similar characters of reference throughout the several views.

In. the course of development of the present apparatus and method of operation, it has been discovered that, quite contrary to gas welding and metal spraying practice; to afford a high temperature at the fusing point in practical operation of a large capacity metal spraying apparatus, it is quite necessary that a large volume of well mixed gas be supplied to the spray nozzle at uniform pressure and in uniform quantity. If

the gas mixture contains an excess of oxygen it will tend to oxidize the metal as it is being laid. To the contrary, if it contains an excess of acetylene it will carbonize the deposited metal. To completely and efllciently burn acetylene gas requires two and a half volumes'of oxygen to one volume of acetylene. Combustion thereof results in two volumes of carbon dioxide to one volume of water vapor. Past practice has demonstrated that it is best to'supply equal parts of acetylene and oxygen gases through the torch and supply ample air to the flame to afford the additional one and one-half parts of oxygen necessary for complete combustion.

In the present instance the equalized oxygen and acetylene gas mixture is supplied through an annular group of jet passages surrounding the wire passage in close association with which is an annular group of air jet passagessupplying to the flames the necessary additional oxygen to build up the required proportion of'one to two and a half acetylene and oxygen mixture.- The equalized-initial mixture supplied through the 'torch is assured only by delivering the gases through fixed openings or jets under uniform pressure. However, unless the gases havebeen thoroughly mixed before delivery to the nozzle, the acetylene gas may burn from one side of the orifice, and the oxygen from the other side. It has therefore been found desirable to meter the gases into a mixing chamber where they will be I thoroughly mixed in a volume greater than is required to supply the flame. By thus providing an excess capacity or reservoir of mixed gas supply greater than the consumption, there is afforded a neutral flame which is free from slight variations and capable of maintaining a uniform operation condition independently of operator control. To maintain such uniform gas supply it is necessary that there be no undue restrictions upon the flow of the gases, either in valves,

conduits, or chambers through which the gases flow to the metering and delivery jets. Such restrictions and lack-of capacity have a detrimental effect upon the pressure and supply maintenance.

To eifect a thorough and rapid intermixture of the fuel gases an intimate whirling motion thereof is induced in a mixing chamber before they reach the discharge passages of the nozzle. After being thus combined they are discharged throughmultiple jet passages, uniformly distributed about the metalpassage of the nozzle.

The main air stream from the compressed air supply tank is delivered under pressure to a mixin'g chamber where, if desired, a third gas may be introduced. This is a valuable feature since while using oxyacetylene gassupply, a small amount of hydrogen introduced into the air supply tends to neutralize the oxygen in the air stream and minimizes the hazard of oxidizing the metal. Likewise, when using butane and oxygen gases as the main gas supply, the introduc-. tion of acetylene. gas into the main air stream enables the metal being laid to be carbonized, thus affording control of the hardness of the I deposit. This provision for delivering a supple-' mental gas intermixed with the air supply whereby oxidization and carbonization can be controlled is a new departuresin metal laying operations and affords possibilities not before available. The proportion "of such auxiliary gas to the air volume is never suflicient to form a combustible mixture. From the mixing chamber pri maryand secondary air streams are delivered through suitable metering jets, by which the volume supplied to the respective nozzle orifices is regulated. The primary air stream supplied from the common air mixing chamber is discharged in a )tubular or hollow jet form entirely surrounding the flame and fusing metal between the heated material and the walls of the melting chamber.

Insteadof discharging the air supply slightly behind the flame as hasheretofore been the general practice, which had a tendency to blow out the flame and necessitated a very high opposing gas pressure, and a resulting tendency to drive the flame back into the wire orifice, the present provided between the air orifices and the fuel gas orifices that the primary air supply folds or deflects the edges of the gas flame inwardly onto fed too fast it will not melt, and if advanced too,

the metal without opposing or fighting the flame so that the flame will be directed to much greater degree onto the metal where an intense heat is generated while at the same time this primary air stream air cools the nozzle structure, Within the end of which the metal is melted. The air passing through the mixing chamber by dissipating heat from the nozzle structure becomes preheated and reaches the point of operation in a dehydrated condition. By delivery of this primary air supply around and ,beyond the flame there is created a suction effect upon the sev-- eral outlet orifices, thus eliminating the possibiliity of driving the fiame'backwardly into the tool and enabling the use of greatly reduced gas pressures.

The primary air stream passes from the nozzle in substantially the form of 'an air pipe serving as a carrier for the molten material to the point of application, thus forming an envelope surrounding the stream of molten metal affording protection thereto as well as a carrying power and greatly reduces the possibility of oxidization of the metal while being propelled through the air. An'adjustment at the end of the nozzle enables the operator to cause the air to take hold of the molten metal earlier or later and affords absolute control. Once set, this adjustment need not be changed except as the material is changed or a different condition of deposit is desired. This carrier air flow is directed at an angle against and flows continguous to the walls of the main nozzle orifice and thus prevents the intense heat from burning the nozzle. Tests have shown that the center of this primary tubular air stream is almosta neutral zone through which the molten metal is carried.

The feeding mechanism for the material supply is a vital factor, especially for a commercial production tool of relatively large capacity as here contemplated. No two different kinds of metal stock fuse at the same temperatures or, conversely, are fusible at the same speed. The fusing point and consequent speed of operation varies with different alloys. If the material is slowly will not clear the nozzle and will give infinite trouble. Therefore, the speed of the wire feeding mechanism must be adjustable, but when adjusted must be capable of maintaining a uniform rate of operation. In the present instance a constant speed motor, preferably of the synchronous type, is employed to drive double cone feeding rolls always at the same speed. The variation of wire feedingspeed is effected by relative adjustment of the point of wire engagement axially of the cooperating cones to zones of different peripheral travel. This affords accurate adjustment to very slight degrees of variation and uniform maintenance of speed in the adjusted positions. At the same time the feeding means is made automatically responsive to variations of diameter of the wire without any material change in. the speed oftravel. This obviates the necessity for expensive wire drawing operations to maintain sizes within small tolerances.

Heretofore much difficulty and damage to tools has resulted from improper operation by shut- 3 ting off the air supply in advance of the fuel supply, or in shutting off one fuel gas in advance of the other. Great care must be exercised not only in shutting off the respective air and gas supplies, but when starting operations. To facilitate operation and eliminate hazard, safety control means is provided by which the tool may be shut off instantly and in proper order when danger arises. a

' Separately operable valves are provided for the severalgas and air supplies which may be manually operated in proper sequence when starting operations. In addition thereto there is provided a spring operated master shutoff device, which it is only necessary to trip manually to effect instantaneous shutoff of all the several gas and air supplies. I

Apparatus.---With the above general explanation-of the method of operation, reference is had to the accompanying drawings in which, for illus- 'trative purposes, but with no intent to unduly limit the scope or application of the invention, there is shown a simple practical form of embodiment thereof. The apparatus comprises generally an electric drivingmotor i including a speed reduction head iA mounted upon a recessed base or support 2 containing the several air and gas supply connections and safety devices, and theme end of which is connected the'housing 3 for the wire feeding mechanism which is driven from the motor I, by suitable speed reduction gear train' including gears within an intermediate gear housing 4.

Extending from the wire feeding mechanism housing-3 in a direction at right angles to the axis of the motor I and wire feeding devices, is a-barrel or sleeve 5 carrying at its extremity the nozzle unit 6. The entire assembly is preferably pivotally mounted on a suitable stand or pedestal for universal adjustment to enable the nozzle to be variously directed to the work.

Nozzle.-The nozzle unit comprises a series of concentric tapered members having therebetween the various air and gas passages and .a central wire passage. The exterior shell or housing I includes a head portion 8 adapted for attachment to the end of the barrel or sleeve 5 and having therethrough in difierentquarter-spaced positions inlet ports for air, acetylene gas, oxygen gas, and a third gas as before mentioned. The peripheral wall of the shell 'or housing member I is externally screw threaded to receive an adjustable air cap collar 9 with which is connected an air cap or nozzle tip in. The air cap I0 is 'of a generally conical shape having peripheralradiating fins and a tapered bore terminating in a concentric outlet.

Throughout a portion" of its tapered interior the air cap I0 surrounds the secondary air nozzle member forming an intermediate annular converging discharge passage II for the primary air stream. Passage H is so shaped at its end as to form a relatively straight tubular passage II for directing the air at an angle against the converging inner wall of the nozzle I 0, so that the air intimately sweeps thereover in a thin, dense skin toward the discharge orifice. The outer converging interior portion of the air cap l0 beyond the end of the air and gas nozzles comprises the melting chamber IZ within which the flame is directed upon the wire stock. The resulting body of fused metal is entrained within the carrier air blast from the annular passage The air cap is axially adjustable upon the housing 1 by rotation of its screw threaded mounting collar 9 to thereby vary the size and capacity of the tapered primary air passage ll 7 intermediate the cap and secondary air nozzle.

, or housing It is secured in such adjusted position by the clamp collar l3 upon the housing.

ing chamber l5 entirely surrounding the nozzle member M and having a communicating air supply port It and a port I! for a third gas through the head portion 8 of the unit. This peripheral air chamber I5 is interrupted by a plurality of spaced peripheral flanges l8 upon the secondary air nozzle it which form a. series of bailies having therein relatively staggered ports l3 through which the air supply must pass from one portion of the chamber to another. These bypass ports iii are not only offset radially, and some inclined to the axis of the nozzle, but they are also circumferentially ofiset relative to each other. The air flowing through such ports from one portion to another of thechamber must pass circumferentially about the nozzle with a whirling motion which with the tortuous course otherwise imposed by the bailie' flanges insures a thorough and complete intermixture of the air supply with the added gas.

The nozzle member I4 is interiorly tapered and receives therein the fuel gas nozzle member 20, the forward tapered portion of which abuts within the tapered bore 'of the air'nozzle l4. Such forward tapered abutting portion of the gas nozzle is provided with circumf erentially spaced longitudinal grooves 2|, which form jet passages for the secondary air discharge. any number of such air ,jet passages,-of which eight is the usual number. The rear. portion of gas nozzle 20 is reduced to cylindrical form, af-

' fording between the nozzle members I and 20 an. auxiliary air chamber 22 which communicates with the air mixing chamber l5 through the stock wire in its advancement through theradial meteringports 23. Thuswhile the primary air stream intermixed, if desired, with a supplemental gas is discharged through the converging annular passage ll contiguous to the walls of the melting chamber l2 and thence through the outlet opening, a secondary air supply is discharged from the same chamber through the metering ports 23 into the chamber ".2 and thence through the spaced jet passages 2| also into the melting chamber l2, but in'intimate relation with the flame. I

The gas nozzle is screw threaded at its rear nd upon a spud 24 seated in a recess 25 in the inner side of the head 8 of the nozzle housing. This spud ,24 also receives therein the screw threaded rear end of the material nozzle 26, and is extended as a tubular guide portion 21 projecting through the nozzle unit head 8 into the adjacent barrel or sleeve 5 to receive and guide nozzle member 26into the melting chamber l2 where it is subjected to the melting action of the flame.

The material nozzle 26 is likewise tapered, at its forwardend and at the rear of the taper is There may be of cylindrical form to agree with the boreof the .fuel gas nozzle member 20, within the tapered ,extremity of the The periphery of portion of which the tapered material nozzle firmly abuts.

the material nozzle is providedwith circumfer entially spaced longitudinal grooves 28 communieating with the enlarged rearward portion 29 of the bore 'of the gas nozzle 20 which serves as a receiving and distributing chamber for the fuel gases which are discharged thence through the spaced jet passages 28 to the fusing chamber l2 where they are consumed. To facilitate rapid dissipation of heat, the metal and

gas nozzles

20 and 26 are preferably, although not necessarily, made of copper. .The fuel gases are supplied through conduits leading from the sources of supply and passing beneath the base 2 and thence through the wire feeding mechanism housing 3 andbarrel 5 to

ports

30 and 3|..in the head 3 of the nozzle housing. The acetylene gas port 30 is connected by a-transverse passage 32 extending through the body of the nozzle housing with the oxygen supply port 3! at the opposite side of the nozzle. Intersecting this acetylene passage 32 is a regulatory or metering valve comprising a screw stud 33 having a tapered extremity coacting with a corresponding tapered seat 34 in the passage to vary the capacity of such passage andso control the flow of the acetylene gas supply.

The oxygen supply passage leading from the port 3| to the mixing chamber 25 is also inter-= sected by a regulatory valve comprising the screw stud 35 having a tapered end coacting with a corresponding tapered seat 36 to vary the capacity of the oxygen passage and so meter the oxygen gas supply. The valve stud 35 has therein a longitudinal bore 31 communicating through lateral ports with a chamber 33 surrounding the valve stud in spaced relationwith the oxygen passage, and which comprises the terminal of the transverse acetylene passage 32. Thus regardless of'the adjustment of the valve stud 35 the flow of acetylene gas therethrough remains constant as regulated by the valve stud 33. The stream of acetylene gas flowing from the bore 31 of the regulating valve is entirely surrounded by a body of oxygen gas flowing between the tapered end of the valve stud 35 and its seat 35. The specific gravity of the respective ases varies greatly, the acetylene gas being much heavier than the oxygen. The inflow of oxygen under break the component gases up and force them into intimate relation by violent agitation.- To intermix the 'gases there is provided within the chamber 25 a ring 39 surrounding in slightly spaced relation the mounting spud and wire guide having a V-shaped peripheral groove forming an annular passage contiguous to the wall of the chamber 25 inwhich the gases may flow in a circuitous path, with more or less rotary motion. Extending from the bottom of the V-shaped peripheral groove in substantially tangential relation with the inner circumference of the ring is a. series of diagonal passages 40 through which the gases pass inwardly into the-annular space 4| intermediate this mixing ring 33 and the mounting and wire guide spud 21. The gases entering such annular space in a plurality of corresponding tangential directions acquires a rapid whirl- 7 lesser number may be ing motion therein. The mounting and wire guide spud 21 is provided with an annularseries of distributing passages 43, leading from the inner annular passage 4| of the mixing chamber into the accumulating space 29. While the bodies of acetylene and oxygen gases will be quite thoroughly broken up and intermingled in their course through the various passages of the mixing chamber, any remaining minute globules of gas will be furtherdistorted and intermixed by being forced one into another during their flow between the

nozzle members

20 and 26 through the restricted passage from the accumulating space 29 to the jet passages 28. This space, although-shown in somewhat exaggerated size in the drawings, is in fact but a few thousandths of an inch in width.

The fuel gas mixture admitted to the enlarged portion 29 of the -boreof the gas nozzle and discharged therefrom through the circumferentially spaced jet passages 28, of which there are preferably a group of eight, although a greater or provided, is consumed at the outlet ends thereof supplying a like number of small bulb-like flames.

} Noegle operation.--As before described, the metal stock in continuous wire form is advanced from the wire feeding mechanism at a uniform rate of speed commensurate with the character of the material through the barrel 5 and thence through the projecting guide tube 21 and the continuing bore of the innermost nozzle member 20 to the melting chamber 12 where it is acted upon by the gas flame supplied with an intermixture of fuel gas from the jetpassages 28 and acted upon by air from the secondary air jets 2|, while around the melting material and reducing flame there is discharged a primary air stream of a substantially tubular form which is interposed between the melting zone and the walls of the nozzle to absorb nozzle from overheating, and also comprising the vehicle for carrying the molten material to the area of deposit, such material being prevented from chilling-en route by the heated condition of the carrier air stream.

Wire feeding mechanism.-Within the housing 3 of the main frame is located variable wire feeding means including a pair of reversely arranged coacting

conical feeding rollers

44 and 45, preferably having hardened and knurled surfaces of approximately forty-five degrees taper. The

driving roller 44 is fixedly mounted on the rotary shaft 46 journaled in suitable bearings 41 within the housing. The shaft 46 projects beyond the housing 3 into the gear housing 4 where it car.- ries a gear wheel 48 meshing with a gear pinion 49 upon the power shaft of the driving motor I which is actuated through a suitable speed re-' duction train. Thus the driving cone 44 is positively rotated at a slow constant rate of speed.

In practice the rotary cone ordinarily possesses a peripheral speed ranging from thirty-five inches per minute at the smaller end to approximately one hundred inches per minute at the larger end, without changing the motor speed or the ratio of intermediate driving connections. Such speeds are here stated merely for illustrative purposes and not with intent to unduly limit the invention. As before mentioned the feeding rate is determined by the character of the material and that of work to be produced.

The complementary cone is an idler loosely mounted on the shaft 50 for rotary and also for limited axial motion. For convenience of assema circular plate or head 5| excess heat and protect the 'tion easily accessible exteriorly thereof.

5 bly and to afford access for inspection, one set of bearings of the cone roller shafts is carried by removably attached to the side of the mechanism housing 3. At its larger .end, the idler cone roller is subjected to the axial pressure of a movable thrust collar or plate 52. Between the thrust member 52 and the cone there is preferably interposed an antifriction ball bearing. The thrust plate 52 is provided with spaced lugs 53 connected by an oscillatory yoke 54 with a rock shaft 55 projecting through the top of the housing wall. A spring lever 56, carried by the shaft, is engageable in different. radial positions with a notched locking segment 51 'on the top of the housing. The thrust of the idler cone 45 is thus yieldingly resisted by the spring lever 56, against the tension of which the cone may yield axially to accommodate between the cones wire portions of slightly varying thickness. By adjusting the spring lever 55 to different positions, the idler cone may be axially shifted relative to the drive cone to adapt the apparatus to feeding wire stock of different diameters.

The wire feeding speed is varied by-shifting the justable wire guide 58 is carried by a reciprocatory rack 59 suitably mounted in inclined guides 60. The rack carrying the wire lead is reciprocated by a gear pinion Bl rotated by a knob or handle 80 exteriorly of the housing 3.

The pinion shaft is screw threaded and carries a threaded locking collar 62 operated by a handle 63 to lock the pinion and rack in their adjusted positions. For convenience of assembly and access for inspection and replacement of the wire lead 58, the rack and pinion are mounted on a circular head or plate 64 removably attached to the rear side of the feeding mechanism housing 3.

Such Wire feed adjusting means is simple but sturdy and unlikely to get out of order. It afiords positive and accurate adjustment of the feeding ratio to minute degree. When adjusted to the proper feeding rate, the pinion and rack are locked in adjusted position.

- Air and gas distribution-The air and gas.

the several conduits is further provided with a' second spring actuated cut-off valve 1|. The spring actuated valves are interconnected for unison operation by a common rock shaft 12, provided with a rock arm 13 connected to the'side bf the mounting base 2 by a, retractile spring 14, which is normally'under tension tending to rock the shaft 12 to close the several valves H. The cut-off valves are held in open condition against the tension of the spring 14 by a substantially U-shaped hand lever 15 pivoted at 15A to the under side of the base.2 with its hand grip por- The hand lever is connected with the rock arm 13 by a short link I6, the pivotal connection of which is ordinarily slightly beyond dead center relation with its connection with the rock arm and so resists the retractive influence of the spring. However, upon a slight oscillatory motion of the hand lever 15 sufficient to swing the link 16 beyond its dead center relation, the valve is un-, locked and the spring 14 retracts the rock arm to simultaneously close all of the valves 1 I, thereby .instantaneously arresting the air and gas supplies. under tension and only a slight movement of the link is necessary to carry it past dead center relation and release the mechanism, a mere touch of the hand lever by the operator is ample to shut off the air and gas supplies. The

several conduits

66, 61, 68, and 69 extend from the base 2 through the housing3 into the barrel orsleeve 5 where they connect with the several air and gas supply orifices in the head 8 of the nozzle housing.

To facilitate the initial insertion oil-the wire' through the guide tube 21 and the metal nozzle 26, a cone or funnel-shaped extension?" is provided upon the guidetube 21 within the sleeve 7 or barrel by which the end of the wire is guided that there is thus provided a device of the charto the nozzle bore in setting the machine for operation. To afford access to the interior of the barrel 5 without dismantling the machin'e,'a door I8 is hinged to the under side of the barrel and secured in closed position by a clamp arm 19.

. From the above description it will be'apparent acter described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages. I

While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosedcomprise the preferred form of several modes of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

Having thus described my invention, I claim:

1. The method of spraying molten material,

which comprises supplying material to be molten and a combustible mixture of fuel and ,combustion-supporting gas to the, melting zone, anddischarging in proximity-thereto a carrier stream of air having a combustible gas intermixed. thereand intermixing with said carrier stream of air a combustible gas to' render inert the oxygen contained therein.

3. The method of spraying molten material, which comprises progressively feeding the material to be molten into a melting zone, and surrounding said melting zone with a carrier stream comprising a mixture of air and combustible gas.

4. The -method of spraying molten material, which comprises feeding the material to be molten to a melting zone, surrounding said melting zone with a carrier stream of air, and introstream.

As the valve operating mechanism is ducinga combustible gas into said.carrier air 5. The. method of spraying molten -material, which comprises feeding the material to be molten to a melting zone, surrounding said melting zone with a carrier stream of air, and introducing into said carrier air stream a gas for regu-.

ing zone with a carrier stream of air, and introducing acetylene into said carrier air stream.

8. The method of spraying molten metal,

which comprises feeding the metal to a melting zone; surrounding said melting zone with a carri'er stream of air, and introducing acetylene into said carrier air stream'to effect carbonization of the metal.

9. In an apparatus of the character described, the combination with material feeding and air and gas supply means, of a nozzle structure including a central passage for material to be melted, air and gas passages around the material passage through which fuel gas and air are discharged in a combustible mixture, a passage for simultaneously supplying a carrier stream of air additional to that supplied for combustion purposes, andm'eans for introducing a gas into the said carrier air stream.

.10. In an apparatus of. the character described, the combination with material feeding and air i supply means, of a nozzle structure including a passage for material to be fused, and fuel and combustion-supporting gaspassages to afford a combustible mixture to the fusing zone, an air passage for a carrier stream of air discharging in proximity to the fusing zone, and means for p intermixing an oxygen neutralizing gas with the air supplied to said carrier stream passage.

11. In an apparatus of the character described, the combination with material feeding and air supply means, of a nozzle strueture'including a passage for material to be fused, and fuel andcombustion supporting gas passages to afiord a combustible mixture to the fusing zone, an air chamber, a discharge passage therefrom for discharging a carrier stream of air past the fusing zone, means for supplying a neutralizing gas to the air chamber simultaneously with the air supply. thereto, and baflles therein for eifecting intermixture of the air and gas prior to their discharge through said passage.

12. In apparatus for spraying molten material,

the combination of asubstantially closed melting chamber having a restricted discharge orifice, means. for supplying a fluid combustible to the chamber under pressure, ineansfor feeding the material to be melted into the melting chamber, means for surrounding the molten material therein with a continuous tubular envelope of air under pressure for conveying the molten material out of the melting chamber through the said orifice to the place of' deposit, and means for introducing a combustible gas into the envelope air.

13. In apparatus for spraying'molten material, the combination of a substantially closed melting chamber having a restricted discharge oriflee, heating means at the opposite side of the chamber from the orifice for forming a melting zone therein, means for feeding the material to be melted into the said melting zone, and means for directing a tubular stream of gas at an angle against the wall of the melting chamber for flow thereover and out of the restricted orifice for drawing the melted material from the melting 20 the place of deposit. 15. In apparatus'for spraying molten material,

the combination of a nozzle member defining a melting chamber and having an annular wall 25 converging toward a restricted discharge orifice,

an envelope of a gas under pressure around the heating means, and means deflecting the gaseous envelope at an angle against the.wall of the melting chamber for movement thereover out of the 0 orifice to convey the molten material to the place of deposit.

16. In an apparatus of the character described, the combination with material feeding and air and gas supply means, of a nozzle st :ucture comprising a plurality of concentric members having intermediate converging air and" gas passages therebetween, and a central passage for the material to be melted, a mixing chamber within the nozzle structure communicating with certain of 40 said passages, and means for creating a turbulence of the fluid flowing through said mixing chamber.

17. In an apparatus for spraying molten metal,

the combination of a fusing zone, asubstantially 45 cylindrical mixing chamber into which different fuel gases are simultaneously admitted, a member therein having passages directed substantially tangentially to the chamber through which the gases passand by which they are givema sub- 50 stantially whirling motion whereby they are intimately intermixed prior to their discharge into the fusing zone, and air supply passages contigheating means in the chamber, means directing 7 vanced thereby.

uous to-the gas passages through which air is supplied to form with the gases a combustible intermixture.

18. In an apparatus of the character described, the combination with material feeding and air and gas supply means, of a nozzle structure including a passage for material to be fused, and

multiple air and fuel gas passages, a mixing chamber into which different fuel gases are simultaneously admitted, means therein for creating turbulence of the gases preparatory to' their discharge through said fuel gas passages, said air passages supplying air independently of the gas 'supply to the combustion zone for intermixture with such premixed fuel gases.

19. In apparatus of the character described, the combination with material feeding and fuel and combustion-supporting gas supply means, of a nozzle structure having a passage for the material to be melted, a mixing chamber in the nozzle structure, a member therein having a plurality oi converging passages, means for separately supplying the fuel and combustion-supporting gas to the mixing chamber for thorough mixing inthe passages of the member, and means for supplying the mixed combustible to the nozzle for,

combustion therein.

20. In a metal spraying apparatus, the combination of a material feeding device'including a pair of cooperating reversely disposed conical feeding rollers, driving means for one of said rollers, the other roller being mounted for idle rotation, at least one of said rollers being axially recip'rocatory relative to the other, and material guiding means adjustable in a plane substantially common with the contiguous faces of the coasting conical rollers adapted by its adjustment to guide the material into different feeding planes of rotation. a

21. In a metal spraying apparatus of the character described, the combination of material feeding means including a. pair of conical rollers of corresponding taper arranged in reverse relation between which the material is passed, means -for transmitting rotative motion thereto, and guiding means for the material adapted to axially vary the plane of rotation in which the material is engaged by the conical rollers and thereby vary the speed with which the material is ad- PURLING A. summing.