US2227753A

US2227753A - Metal spray gun

Info

Publication number: US2227753A
Application number: US234869A
Authority: US
Inventors: Herbert S Ingham
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-10-14
Filing date: 1938-10-14
Publication date: 1941-01-07
Anticipated expiration: 1958-01-07

Description

Jan. 7, 1941. H. s. INGHAM METAL SPRAY GUN Filed Oct. 14, 19558 6 Sheets-Sheet 1 INVENTOR Q ZW ATTORNEY Jan. 7, 1941.

' H. lNGHAM METAL srnu GUN 6 Sheets-Sheet 2 Filed Oct. 14, 1938 N N n m R Q I Q w N a... T N h v 0 Nil; m% m ww W NXENTOR ()fi ATTORN EY Jhn-7,l941- HbfilNGHAM METAL SPRAY GUN Filed Oct. 14, 1958 e Sheets-Sheet s INVENTOR W m lllfi ATTORNEY Jan. 7, 1941. H. s. INGHAM 2 ,7

METAL SPRAY GUN Filed Oct. 14, 1958 6Sheets-Sheet 4 Jan. 7, 1941. H. s. INGHAM METAL SPRAY GUN INVENT OR.

ATTORNEY.

wwvlf Jan. 7, 1941. H. s. INGHAM METAL SPRAY GUN 6 Sheets-Sheet 6 I 11.. L m n kd i g p v. N 0% m:

Filed Oct. 14, 19

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INVENTOR. ATTOZRNEY. Y

Patented Jan. 7, 1941 UNITED STATES PATENT OFFICE METAL SPRAY GUN Herbert S. Ingham, Jamaica, N. Y. Application October 14, 1938, Serial No. 234,869

9 Claims. ill-42.2)

My invention relates to metal spray guns and will be fully understood from the following description read in conjunction with the drawings in which:

Fig. l is'a side view of a metal spray gun constructed in accordance with my invention.

Fig. 2 is a vertical section through the construction shown in Fig. 1 on the plane indicated Fig. 3 is a vertical section through the construction shown in Fig. 2 on the plane indicated by III-J11.

Fig. 4 is a vertical section through the construction shown in Fig. 1 on the plane indicated 16 by IV--IV.

Fig. 5 is a vertical section through the construction shown'in Fig. 1 on the plane indicated by V-'-V.

Fig. 6 is an exploded section through thecon 2o struction shown in Fig. 1 on the plane indicated by VI-VI.

Fig. 6a is a plan view of the interior of the construction shown in exploded form in Fig. 6.

Fig. 7 is a side view of one element of the gun 25 constructed in accordance with my invention.

Fig." 8 is a view of the construction shown in Fig. '7 at a right angle to the showing in Fig. '1.

Fig. 9 is a central vertical section parallel to the construction shown in Fig. 1.

30 Fig. 10 is a vertical section through the construction shown in Fig. 5 on the plane indicated by X-X. v

Fig. 11 is a section on the plane indicated by ICE-XI in Fig. 5.

35 Fig. 12 is a section through the construction shown in Fig. 11 on the a plane indicated by X II-XII.

Fig. 13 is a section on the plane indicated by XI-XI in Fig. 5 showing an alternative embodiment of my invention.

Fig. 14 is a corresponding section showing a further alternative embodiment of my invention. Fig. 15 is a corresponding section showing a further alternative embodiment of my invention. Fig. 16 is a corresponding section showing a still further alternative embodiment of my in,- vention.

Metal spray guns'of the type to which my invention relates are devices which operate by con- 50 tinuously feeding a metal rod or wire into a zone in which it is melted and from which this melted metal is sub-divided and propelled by a blast of air or other gas. The rod or wire is fed into the melting zone by knurled burs which press 55 against opposite sides of (the wire and are driven by a gas turbine operating through reduction gears. The load on the turbine varies from time to time due to changes in the position of the operator, kinks in the wire, etc., and since it is essential that the rate of feed of the wire be uni- 5 formly maintained, it is likewise essential that the turbine have a comparatively stable speed of operation, 1. e., that its speed be affected as little as possible by variations in the load. This may be accomplished by appropriate turbine con- -10 struction.

In the operation of metal spray guns, it is, however, necessary to'maintain different rates of feed when spraying different metals; for example, metals, the heats of fusion of which are 15 low, may be fed and sprayed more rapidly than metals with a high heat of fusion, and wires of larger diameter are fed and sprayed more slowly than wires of the same material of smaller diameter. In usual practice an effort is made to 2 approximate proper-conditions for the particular metal being sprayed by the provision or replaceable gearing designed to permit the gun to be operated at the desiredrate of wire feed while permitting the turbine to operate within a range of stable operation. Changing the gearing involves a loss of time and the pos ibility that metal particles will be picked up by the gears in handling and interfere with the operation of'the gun. If

an effort is 'made to reduce the turbine speed by throttling the gas the turbine becomes unstable and a uniform wire feed is no longer maintained,

I have devised a new metal spray gun in which no change of gearing is necessary and by means of which it is nevertheless feasible to maintain two, or, in fact, any number of rates of wire feed within limits practically desirable, shifting from one speed to another by simple adjustment and notwithstanding such changes in the rates of feed, maintaining the turbine at all times in a range of stable operation. Broadly speaking, I accomplish this purpose by varying the average angle of the turbine nozzle or nozzles with respect to the turbine blading and this may be done within'the scope of my 5 invention, either by means for continuously varying the nozzle angle over a predetermined range, or by varying the same in steps. .By use of the nozzle or nozzle setting which projects the gas mostnearly in the direction in which the blades are travelling, thus giving the maximum propulsive component of the velocity of the gas,

the stable range of greatest speed is obtained. Ther stable range of. lesser operating speed is obtained byuse of the nozzle or nozzle setting which projects the gas less nearly in the direction in which the plates are travelling, thus giving a lesser propulsive component of the velocity of the gas. In accordance with this principle, where I provide a turbine nozzle or nozzles, the average angle of which may be continuously varied, any number of stable operating turbine speeds may be obtained, within the limits for which the turbine was designed. Alternatively, I may apply the principle of my invention by the use of a number of jets in which the average nozzle angle of some units or groups of the total number is difierent from the average nozzle angle of other units or groups. Each of the units or groups is designed to maintain the turbine within a particular stable range of operating speeds and the change from one range to another is achieved by selecting a particular unit or group. In either case above-referred to, when the par- Y ticular adjustment for the desired operating speed range has been selected, the line pressure may be throttled to maintain desired within this range.

For the purpose of illustrating the scope and character of my invention, I have hereinafter describeda spray gun containing certain practical embodiments of the same. Referring to the drawings, I (Fig. 2) indicates the inlet for oxygen or other combustion supporting gas, 2 the inlet for acetylene or other combustible gas, and 3 the inlet for air or other gas for use to project the metal spray and drive the turbine.

Each of the said inlets is connected by a suitable fitting and flexible tubing to a source of required gas. When plug 4 of valve 5' is in the position shown, each of the inlets registers with a corresponding hole in theplug, these holes being indicated by 40 tively. When handle 8 and plug 4 are in the position shown, oxygen flows through duct l0 into duct II. The combustible gas flows through duct |2 to mix with the oxygen in duct II. The air flows through duct I5 into chamb'er l6 and 45 also flows through the side connection H con-' trolled by needle valve l8 into turbine manifold l9. Openings 5, 6 and 1 in plug 4 are so arranged that as handle 8 is turned from the off position which is at a right angle tothe show- 50 ing in Fig. 2 first some combustible gas passes into duct I I and thence to the burner outlet to enable the burner to be lighted, some air passes simultaneously into manifold Hi to enable the turbine to come up to speed.. Alternatively, all -55 the valve passages may be opened but at such rates of flow as to establish favorable lighting conditions which are diflerent from the conditions obtaining when the gun is in operation- This position of the valveis called the lighting 60 position. Under former practice a certain degree of experience was necessary to enable the operator to turn the handle 8' to the exact posi- 'tion at which the burner may be properly lighted, but with my construction this diificult'y is elimi- 65 hated, the washer 20 (Fig. 3) defines a hole 2| of rectangular crosssection which fits closely the shank 22 (of corresponding section) (Fig. 2) of the plug 4. The washer 20 is formed with the depression 23 (Fig: 3). This washer is spring 70 pressed, and this depression slips onto the head of pin 24 when handle 8 is in the correct position for lighting the burner. This ofl'ers sumcient resistance to indicate to the operator the lighting position. After the burner has been lighted 75 a slight pressure against handle 8 forces the dethe exact speed numerals 5, 6 and 1 respecpression 23 out of engagement with the head of the pin 24. A further movement of handle 8 causes oxygen to flow through duct it which establishes a melting fiame with the ignited gas and the final movement of handle 6 to the position shown in Fig. 2 permits air to flow into duct l5 and thence into chamber 06 to project the sprayed metal upon the surface to be covered.

Theconstruction of that part of the gun by which the rod or wire is melted and projected will be explained by reference to Fig. 9. The wire 3? moves forward to guide and through duct 32 to the interior 33 of the burner tip 34. The mixture of gas and oxygen move forward through the duct l, which is immediately behind duct 32 (the arrangement is shown in Fig. 2) and into the annular space 35. annular space 35 the combustible mixture moves forward through a number of holes to be discharged through convergent orifices 36 against the wire. This forms a zone of gases undergoing combustion, whereby the wire 3? melts as rapidly as it is progressively advanced into the zone, for which reason this zone may be hereinafter referred to as a melting zone. The air from chamber l6 advances through the annular space 40 surrounding burner tip 34 and is projected by air nozzle 4| in such a way as to sub-divide and propel the molten metal. Theair tip- 4| is threaded to the outer shell 42 of the burner so that the orifice 43 defined by conical interior of air tip 4| and conical exterior of burner tip 34 may be adjusted with corresponding variations in the characteristics of the air blast. When a satisfactory adjustment has been made, the tip 4| is locked in position by the lock nut 44. It will be noted that the air in passing forward from the chamber l6 goes through the constricted annularspace 45 which exerts a definite control over the volume of air passing. As a result of this constriction and the orifice eflect thereby created, the adjustment of air tip 4| modifies the characteristics of the air blast without so great a modification of the volume of air passing thereto as would otherwise result, which is decidedly advantageous in the adjustment and operation of the gun.

The wire 31 (Fig. 9) enters the gun through the annular guide of hardened material in which isthe duct 5|. The upper and lower surfaces of the wire are engaged respectively by the

burs

52 and 53. Bur 53 is carried by shaft 54,

which shaft is driven by an air turbine through suitable intermediate gearing which will be hereinafter described. Shaft 54 (Fig. 4) also drives the gear 55 in mesh with gear 56, which in turn drives the upper bur 52. Both gear 56 and bur 52 are secured to the tubular member 51 which rotates on the spool 58 carried by pin 59 (Fig. 4) The screw 59 is carried by the saddle 60 and this saddle is pivotally secured (Fig. 9) to frame 6| of the gun by the hinge 62. When cap is turned the threaded end 66 of the screw 6'! advances into the threaded member 68 which is a part of frame 6| and the spring 10 exerts pressure on the saddle 60, thereby forcing the upper bur 52 toward the lower bur 53 and thereby causing the burs to engage and advance the wire-i'l. Conversely, when cap 65 is turned in the reverse direction, pressure of spring 10 on saddle 50 is released and the burs move freely without engaging and advancing the wire.

The shaft 54 (Fig. 4) which drives bur 53 is mounted in ball-bearings l0 and II. Bearing 10 is held in frame 6| and bearing ,H

is held From this variable angle.

in the housing I2 which is attached to frame GI. The shaft 54 is driven by the worm gear I3, which in turn is driven by the worm I4, carried by the shaft I5. Shaft 15 (Fig. 10) is carried by ball-bearings I6 and TI mounted in the housing I2. Shaft I5 is in turn driven through the worm gear I3 by the worm I0. The worm I0 (Fig. 5) is integral with shaft carried by

bearings

85 and 36. Bearing 85 is mounted in housing I2 and bearing 86 is mounted in thecap or cover 90 of the turbine BI. 7

Turbine 9| (Fig. 5) includes the turbine rotor drum secured to shaft 80 by the set screw 36. Details of the blading I00 are apparent from Figs. '7 and 8. As evident from the exploded view (Fig. 6) of the cover 30, this cover includes the mounting IOI for the ball-bearing 80 and three ridges I02 radially arranged about mounting IOI on the interior surface of the cover. The

washerrshaped member I03 is made of fine wire mesh and rests directly upon ridges I02. The washer I04 rests directly on the washer I03 and is composed of fiber. The fiber washer I04 defines the perforations I05 (Fig. 6a). The washers I03 and I04 are held in contact with each other and with the ridges I02 -by the'strips I05, which in turn are secured to the ridges I02 by the screws I01. One result of this constructionis that the exhaust from the turbine fiows through perforations I05 in the fiber washer I04, thence through the openings in the fine screen of which washer I03 is composed, and thence through exhaust ports of the turbine IIO,-formed in thecover 90 (Fig. 6 and Fig. more quiet operation of the turbine. The strips I05 form ridges in the space in which the bladed drum of the turbine revolves. These ridges operate to broaden the range of stable operation for any given setting of the turbine nozzles by producing turbulent fiow of gas within the turbine.

One nozzle falling within the purview of my invention is shown in Figs. 11 and 12. Fig. 11 shows the face II5 which (together with the housing 30) defines the space in which the turbine drum rotates; the drum is not shown to facilitateinspection of the nozzle structure. In this case one individual nozzle H5 is shown which is of bore III and the plug IIO which is turned within bore I II to vary the discharge angle of the nozzle.

By reference to Fig. 12 it will be, seen that by turning the plug II3 nozzle IIG discharging through the recess III! against the blading I20 of the turbine drum can be made to assume any intermediate position between the mechanical limits. The back of the plug is cut away at I2I so that it will be at all times in communication with the manifold I9 through the side outlet. I22. The preferred form of nozzles for practical applications is that shown in Fig. 13 in which the nozzle I30 is permanently connected to the manifold III while nozzle I3I may at any time desired, be additionally connected by turning plug I32 so that hole I33 defined by the plug registers with inlet I34 of nozzle i I3I. In this case the nozzles I30 and I3I have different angles of discharge with respect to the turbine blading and the nozzle I3I discharges the gas with a lowerpropulsive component than nozzle I30. In this case it is evident that when both jets are in operation the 1) thereby resulting in This nozzle is composed of the of gas against the blading of said sure in manifold I3 will be so controlled, either -by the provision of afixed orifice, or by throttling that the air pressure in manifold I9 is such as to drive the turbine within the range of lower operating speed. v

A further alternative form of construction is shown in Fig-1'4 in which case I have shown two nozzles, I35 and I36, which may be brought alternatively into communication with manifold I9 by turning the plug I31 so that the holes in the tubular portion I30 of the plug register with either inlet to nozzle I35 or inlet to nozzle I35. In this case It will, of course, be understood that the angle of discharge of one nozzle is diflerent from the so that the propulsive component of the as delivered from one nozzle is different than the propulsive component of the gas delivered from the other nozzle, and the stable range of lower'operating speed is obtained by the use of the nozzlewhich delivers with the lesser propulsive component of the velocity.

A further alternative embodiment of my invention is shown in Fig. 15. This also comprises two nozzles which may be alternatively used. Nozzle M0 is in communication with manifold I0 through side arm I controlled by needle valve I42. Nozzle I43 is in communication with manifold I3 through side arm I44 controlled by needle valve. I45. The angle of discharge of nozzle I is different from the angle of discharge'of nozzle I43 with respect to the turbine blading. A lower stable operating speed is obtained by the use-of the nozzle which has the lesser propulsive component of the velocity of the gas discharged. Since in this case the amount of gas *discharged through either Jet may be accurately controlled by the needle valve so that the turbine operates within the range for which the jet was designed, the use of a restriction or valve controlling the admission of air into the manifold I0 is not esarigle of dischargeof the other nozzle,

sential although in practical operation it is desirable.

A still further'embodiment of my invention is shown in Fig. 16 in which case the turbine is pro vided with four separate nozzles numbered respectively I50, I5I, I52 and I53. Communication of these nozzles with manifold I0 is controlled by tubular section I54 of the plug I55 in manifold I5, so that any one of the nozzles may be brought respectively into communication with manifold I0 by turningthe plug I55.- The angle of discharge of each nozzle with respect to the turbine blading is different from the angle of dis.- charge of any other nozzle, 1. e., the propulsive component of the velocity of the gasdischarged is different and any one of four stable ranges of speed may be obtained by the use of the nozzle appropriate tothe particular range.

The foregoing description is furnished by way of illustration and not of limitation, and it is, therefore, my intention that the invention bellmited only by the appended claims or their equiva lents wherein I have attempted to claim broadly all inherent novelty. I

I claim:

1. In a metal spray gun of the molten metal gas blast type having means controlling the supply of combustible gas and oxygen, an inlet for compressed g'as, and turbine actuated means for progressively advancing metal into a melting zone and including in said turbine a rotor drum and nozzle means positioned to direct a blast rotor drum,

the improvement comprising means for varying the angle of discharge of said nozzle means with respect to the direction of travel of said bladlng, independent of the means controlling the supply of combustible gas and oxygen to said gun.

2.. The improvement in a metal spray gun according to claim 1 in which said turbine comprises in addition a manifold in communication with said nozzle means and pressure reduction means between the inlet for compressed gas and said manifold.

3. The improvement in a metal spray gun according to claim 1 in which said turbine comprises in addition at least one gas baifie within the same positioned tov produceturbulent how of gas therein in air frictional engagement with said rotor drum. 6

4. In a metal spray gun of the molten metal gas blast type having means controlling the supply oi combustible gas and oxygen, an inlet for compressed gas, and turbine actuated means for progressively advancing metal into a melting zone and including in said turbine a rotordrum and a nozzle positioned to direct a blast of gas against the blading oi said rotor drum, the improvement comprising means for varying the angle of discharge of said nozzle with respect to the direction of traveloi said blading, independent of the means controlling the supply of combustible gas and oxygen to said gun.

5, The improvement in a metal spray gun according to c1aim'4 in which said turbine com- 7 prises in addition a manifold in communication with said nozzle means and pressure reduction means between the inlet for compressed gas and said manifold. a

aas'mes 6. The improvement in a metal spray gun according to claim 4 -in which said turbine comprises in addition at least one gas bafie within the same positioned to produce turbulent now a blast of gas against the blading of said rotor drum, the angle of discharge of at least a part of said nozzles being difierent from the angle of discharge of the remainder of said nozzles, the improvement comprising means for selectivelyplacing a part of said nozzles in use independent of the means controlling the supply of combustible gas and oxygen to said gun.

. 8. The improvement in a metal spray gun according to claim 7 in which said turbine comprises in addition a manifold in communication with said nozzle means and pressure reduction means between the inlet for compressed gas and said manifold,

9. The improvement in a metal spray gun according to claim 7 in which said turbine comprises in addition at least one gas baiiie within the same positioned to produce turbulent flow of gas therein in air frictional engagement with said rotor Y HERBERT S. INGHAM.