US2228226A - Device for spraying paints, lacquers, or other liquids - Google Patents

Description

Jan. 7, 1941. A, HQDowNs 2,228,226

DEVICE FOR SPRAYING PAINTS, LACQUERS, 0R OTHER LIQUIDS ,Filed April 27, i932 2 sheets-sheet 2 1f/1v .5. I .6.

rg I g 492/93 /f f/. 9

ATTORNEYS Patented Jan. 7, 1941 DEVICE FOR SPRAYNG PAINTS. LACQUERS, R OTHER LIQUIDS Application April 27. 1938, Serial No. 204,550

9 Claims. (Cl. 299-1401) This invention relates to improvements in devices for spraying light bodied or low specific l gravity materials such as lacquers and varnishes, as well as heavier liquids such as paints, or semipastes, etc., and the principal object is the provision of such a device which is highly eiilclent in operation, simple and readily controlled to use a minimum amount of material and a minimum amount of air or gas pressure to accomplish the l0 best atomizing results.

' Further objects include the provision of such a device in which the trigger control is very accurate and simple, which operates at low air pressures and volumes and with a low consumption l5 of materials. thereby reducing the amount of mists and fumes to a minimum and still affording perfect atomization of the material and application thereof to the surface being coated.

Another object of the invention is the provi- 20 vision of a new and improved system of air distribution within the device, the air leads to the nozzle of the device from al single valve controlling the air supply being branched into two independent leads, one of which is adapted to be 25 separately regulated whereby when a slot type nozzle, to be hereinafter described, is used, the.

volume of air can be cut down for the proper application of light bodied or low specific gravity materials, and when an external nozzle, also to 30 be hereinafter described, is used the air supply can be changed to vary the width of the fan spray and/or produce a conical spray.

Another objectof the invention is the provision of a new and improved form of nozzle construc- 35 tion whereby the liquid is completely atomized therein and delivered therefrom in the form of a fan-shaped sheet of iinely divided spray of substantially uniform density throughout its entire extent. By fan-shaped, I mean daring or 40 divergent in Width, but preferably of small depth Y or thickness.

A further object is the provision of an improved form of fluid tip construction for my device to insure even air distribution through slots or 45 grooves arranged in novel manner on said tip and thus to co-operate with my new and improved nozzle construction to eiect proper and complete break-up or atomization of the coating material.

.50 Still another object of my invention is the provision of a new and improved form of externaltype nozzle to be used with my,device, comprising essentially an outer and an inner part or piece; the inner piece having two milled slots or '55 grooves which cause two Jets of air to strike against the sides of the fan-spray resulting in a more even distribution of material and a better break-up or atomization. Another object of this invention is the provision of such a device in A which the entire body and handle aremade of 5 one piece, preferably by die-casting or forging, whereby the manufacture of the same is simplified and cheapened and at the same time a more attractive appearing and substantial device is provided. 10

A further object of this invention is the provision of slot typev nozzles having slots of varying widths and lengths of slots to produce effective and desirable results under diierent conditions and with diierent types of coating materials.

And yet another object of this invention is the provision of nozzles which may be machined to have sharp outside edges which prevent the accumulation of coating material vabout the nozzle or inthe passageways of the device whereby clogging is avoided and in eiect the device is to a large measure self-cleaning.

Further objects include improvements in details of construction and are hereinafter set forth in full. n

To the accomplishment of the foregoing and such other-objects as may hereinafter appear, the invention consists in the novel construction, combination and arrangement of elements or parts hereinafter described and then sought to be defined in the appended claims, reference being had to the accompanying drawings forming a part hereof and which show, merely for the purpose of illustrative disclosure, preferred embodiments of my invention, it being expressly understood, however, that various changes may be made in practice within the scope'of the claims without digressing from my inventive idea.

In the accompanying drawings, in which similar reference characters denote corresponding 40 parts:

Figure 1 represents a vertical longitudinal, cross-section through a device constructed to embody my invention shown in inoperative or closed condition in full lines, the open position of the trigger being indicated -in dotted lines, Said iigure also showing a slot type nozzle applied to the device and illustrating the relative position Aof the fluid tip with respect to said nozzle;

Figure 2 is -a horizontal longitudinal section 50 taken along line 2--2 of Figure 1 and viewed in the direction of the arrows, illustrating in detail the new and improved system of air distribution from the air control valve to the nozzle;

Figure 3 is a partial vertical cross-section taken 55 along line 3-3 of Figure 1 and viewed in the direction of the arrows illustrating details of the air and uid passageways to the nozzle of the device;

Figure` 4 is a front elevation of one form of slot type nozzle;

Figure 5 is a rear elevation of the said nozzle, partially broken away to illustrate internal structure thereof; l Figure 6 is a partial enlarged longitudinal section of the nozzle'end of the device oi Figure 1 with an' external type nozzle applied thereto in place of the slot type nozzle of Figure 1 and showing the relative lposition of the fluid tip with respect to said nozzle;

Figure 7 is a cross-section along line 1-1 of Figure 6 viewed'in the direction of the arrows:

Figure 8 is a front elevation of the said external type nozzle partially broken away to illustrate the internal part of the said nozzle structure;

Figure 9 is a perspective view of the said internal part;

Figure 10 is a front elevation of a modied form of external type nozzle, broken away in part to illustrate details of its internal structure;

and

Figure 11 is a cross-section along line I I-II of Figure 10 showing the relative position of the fluid tip with respect to said nozzle.

Referring now'tothe drawings, and rst to p Figures 1 to '1 inclusive, the numeral I designates the body of the device as a whole, this body including the barrel portion 2 and the handle portion 3, the handle portion extending downwardly from the barrel portion and inclined slightly to the rear so that the device has somewhat the appearance of an automatic revolver.

Devices of this kind are employed to spray material principally for coating purposes, the material being atomized by air under pressure. The material is fed to the point of atomization by pressure and consequently this device has parts, passages and valves for controlling the admission and passage ofthe pressure fluid as well as the liquid material and the atomization of the same. A connection 4 to a suitable source of air or other uid under pressure is made in `the internally threaded opening 5 on the lower end of the handle portion 3. Usually this pressure is automatically maintained by suitable regulating means, as is well understood. rlthis opening 5 leads to the passage 6 which extends upwardly through the interior of the handle 3 to the air inlet valve chamber 1 in the barrel portion of the device (Figs. 1 and 2). This valve chamber is provided with a valve seat 8 leading to the distributing chamber 9. A passageway I0 leads from this chamber directly to passageway II, which latter extends along the barrel interior toward the nozzle end of the device. A second passageway I2 leads from distributing chamber 8 to a valve chamber I3 to be presently described.

Mounted in the valve chamber 1 is a suitable valve member I4 having the valve proper I5 adapted to engage the seat 8 and having the operating stem I6 extending forwardly therefrom and through a suitable bearing opening I1 in the barrel body into an open slot I8 in said barrel body, as shown, to bear against a trigger to be presently described. The rear end of the valve member I4 is provided with the stud or projection I9 to receive one end of the coil spring 20, the other end of which is positioned in a socket ZI in the securing and tensioning adjusting nut 22 which is screwed into the rear end of the valve chamber 1. By this means, the valve I5 is normally held in tight engagement with its seat 8 so that no air pressure is admitted through the passages 6, 1, I0, II, I2 and i3 unless the valve is opened.

The valve chamber I3 is provided with a valve seat 23 leading to a passageway 2d which extends in the same direction as passageway Il along the barrel interior toward the nozzle end of the device. Alneedle valve 25 is mounted in the `valve chamber I3 through the internally threaded portion of the mounting nut 26. At its outer end the valve terminates in a manipulating knob 21 by which the inner or valve end 28 may beadjusted relative to the valve seat 23 to regulate the flow of air into passageway 24 .as desired and to cut it oil completely if required, al1 for a purpose to be hereinafter described.

The trigger above referred to is designated by the reference character 29 and has the downwardly extending portion 30, adapted to be engaged by certain fingers of the hand of the operator, the upper portion 3I of the trigger extending into the triangular slot I8 of the' device and being pivotally supported at 32 in the said slot by means of a suitable pivotor bolt 33 (see Fig. 1). The rear face of the trigger is provided with a bearing face 34 on the rear side which engages the front end of the valve stem I6, and when the trigger is forced rearwardly the valve stem and its attached valve I5 are forced rearwardly .and the valve forced o its seat to permit the admission of air through passages previously mentioned. The rearward movement of the trigger is limited by means of the abutment of the portion 30 against the external face of the handle 3. Spring 20 is of sufficient strength to normally hold the valve I5 closed and the trigger in its extended open position shown in full lines in Figure 1 of the drawings, and to cause these parts to assume these positions when the pressure is released from the trigger and to cause these parts to move from these positions when the pressure on the trigger is reduced. Thereby a very simple and delicate control is provided for controlling the admission of air into the device and it is very easily regulated by an operator and without the necessity of long training and experience. For further ease of manipulation and to insure a firm grip, the handle 3 is provided with a finger lug or guard 34 projecting from said handle directly below and adjacent the lower end of the trigger.

The barrel portion 2 extends in a horizontal direction forwardly from the handle portion 3 and is provided with a curved lug or hook or iiange 35 to provide a convenient hanging means -spring chamber 39 and a centralaxially aligned opening 40 therewith at its rear end.

The valve rod 4I, which controls the supply of liquid material: extends in to chamber 31 through its front end and is movably mounted within the forward lbearing part 42 of the central barrel bore. Inside the chamber 31 said rod 4I is enlarged in diameter at 43 and provided with two spaced shoulders 44 and 45. A vertical slot 43 is provided in the rod between theshoulders 44 and 45Cand the upper portion 3| of the trigger passes therethrough and is movable therein. The rear end of rod 4| is provided with an internally threaded bore 43 extending from the said end 'through the rear end of the slot 46. Threadedly engaged in said bore is an operating rod 41 whose forward nose 41 projects into said slot and is adapted to be engaged by the trigger 29 when the latter is moved into operative position as hereinbefore described. Operating rod 41 at its rear portion is hexagonally shaped in section as at 41 or may be any other polygonal shape. A riveting collar 48 is slidably borne to the rear end 4of thevrod. The inner flange 43 ofthis collar is adapted to engage an inner shoulder 4I formed on the nut 38. A rotatable knob 49 is mounted onthe collar 43 and the outer edge of the latter flanged over at 48210 rivet said knob in place whereby rotation of the knob willmtate said collar and in turn the rod 41 through engagement of said collar with the hexagonally shaped portion thereof.

Intermediate its ends, the rod 41 is provided Awith a slida'ble ring member 55. A spring 5| mounted about the rod 41 is provided, one of its ends bearing against shoulder 45 and its other end against one face of the ring member 50. A second spring 52 is also provided, `one end of which engages the opposite face ofthe ring member il and whose opposite end engages the flange 43'. The springs 5| and,52 normally urge the rod 41 and consequently valve rod 4| forwardly to close the valve controlling the inflow of fluid material.

Vwell as a ilne control of the relative time of opening of the air valve l and the fluid valve when the trigger is moved. In fact, the timing may be thus controlled to effect simultaneous operation of the air and fluid valves or later opening of the fluid valve with respect to the air valve. In Figure 1 the position of the nose 41' is such that the trigger 3| will first engage the valve rod l5, open the air valve I5 and then engage the nose 41' to Vopen the fluid valve. This timing feature is ofl great importance as will presently be shown.v

The forward end of the barrel is provided with a longitudinal bore forming a liquid receiving chamber 52 which in turn communicates with the material supply passage 53 which extends downwardly through the downward extension 54, this downward extension having its lower portion screw-threaded as at 55 to afford a connection leading from a suitable pressure fluid container shown diagrammatically in dotted lines, and which. for example, may be a device such as that -described in the Austin H. Downs Patent No. 1,706,875, issued March 26,' 1929.

Receiving chamber 52 is in axial alignment with valve operating chamber 31 and valve rod 4| projects into said chamber and is slidably movable toward and away from the front end of the chamber, being slidably borne and guided in a packing nut 56 screwed to the rear end of said chamber. The rearwardly extending portion 55' of the nut 56 is externally threaded and a hollow clamping nut 51 is screwed thereon serving to provided with the screw-threaded extension 32,

whereby it is secured in position engaging the forward screw thread 53 of the receiving chamber 52. It has a hexagonally or polygonally shaped ange 53r directly adjacent the extension 52, a cylindrical portion 34 equal in diameter to the perpendicular distance between opposite flat faces of the hexagon or polygon, adjacent said flange, a conical portion y65 adjacent said cylindrical portion I4 and a small diametered cylindrical nose at`its forward end located at the apex of said conical portion.

Longitudinal slots 51 are provided in the tip 5|, being centrally located with respect to each of the hexagonal faces 53' of the -flange 53 andy extending from substantially the forward half of each hexagonal face and through the entire length of cylindrical portion 34. These slotsare uniformly deep throughout their length except at their rear ends where their bottoms curve outwardly at 31' to terminate in the respective faces of said flange 33.v The fluid tip 6| is bored entirely through as at 53 along its longitudinal center line from the nose 35 to the rear face of extension 52, forming at its rear face a valve seat 53' on which the tapered valve 4| on valve rod 4| is normally adjusted torest in closed position and to seal the fluid receiving chamber 52. When said valve 4I' is opened by pressure on the trigger as before described, fluid passes from the chamber 52y and out through the forward end of the bore in the Dose 55. t

The air passages and 24 extend horizontally along the barrel toward its forward end, to the rrespective chambers 69 and 10 (Fig. 2) converging slightly in their approach thereto. A passageway 1| extends upwardly and outwardly in the barrelv 2 from the chamber 69 terminating in the fiat face 50 of said barrel directly adjacent the flange 53 for a purpose to be presently described. A passageway 12 leads upwardly and outwardly in the barrel 2 from the chamber 10 also terminating in the hat face 60 of such barrel at a diametrically opposite point to said passageway 1| and at substantially adjacent the outer edge of said face. The chambers 59 and 10 are provided to facilitate theboring of the respective passageways 1| and 12 and each is suitably sealed by the respective sealing plugs 13 and 14. In this manner, two continuous air passages from the air distributing chamber 9 to the tip end of the barrel are provided, one of which is independently valve controlled through the valve 28 whereby air'through passageways 24 and 12 may be adjustably restricted or cut off entirely as desired.

The nozzles to be applied over the fluid tip may as heretoforememtioned be either of the slot or the external type or of other types. Nozzle 15 which is shown in Figures 1, 2, 4 and 5 is of the nozzle is of general cylindrical form being substantially hollow and adapted to be applied over the fluid tip 5| with its inner or bottom edge slot'type. This nozzle, which I term a fan slot A 15' abutting the ilat face 80 of the barrel. The nozzle has a cylindrical passage 18 near its forward end into which the cylindrical nose part 68 of the iiuid tip projects, the diameter of said passage being larger than that of said part 66 for the passage of air and 'forming an atomizing chamber. Behind the cylindrical passage or chamber 15 is a conical passage 11 which is spaced from the conical portion .65 of the uid tip. This conical passage joins a cylindrical chamber or passage 18 whose diameter is sub-v stantially larger than the diameter of the cylindrical portion 64 of the fluid tip. A partition 18 is provided in the nozzle immediately behind the chamber 18 and has a central bore 19 through which the said cylindrical portion 64 of the tip projects, iitting snugly against the walls of said bore. An enlarged cylindrical chamber 88 is provided behind the partition, its diameter being large enough to permitfree passage into it of airA from the air passages 1I and 12. 'I'he partition 19 is provided with a plurality of equally spaced passages or holes 8| permitting air to pass therethrough to the forward passages of the nozzle heretofore described and serving to distribute said air uniformly. 'I'he forward end of cylindrical passage 18 leads into a flat fan shaped or arcuate slot 82. It is to be noted that the cylindrical passage 18 in the nozzle extends in the nozzle body beyond the innermost edge of the fan slot and as the slot is less in width than the diameter of the l passage or atomizing chamber 16, shoulders 82 are formed and these shoulders assist in breaking up the liquid by diverting the direction of flow of the air and-causing the air to undergo a. sharp change of direction and to pass into and across the stream of liquid as it .emerges from the portion 66 of the fluid tip in said atomizing chamber. This chamber 18 is located centrally with respect tcthe slot. Furthermore, the air stream itself is broken up by the numerous abrupt changes of direction it undergoes in passing from the ch-amber 88 through the various holes and passages hitherto described before it reaches the atomizing chamber 16. Thisbreaking up of the air and the abrupt changing of direction of flow of the air across the stream of fluid as it emerges from the uid tip results in complete breaking up and atomization of the liquid and its discharge in the form of a finely divided spray of uniform density. This action also retards the direct ow of liquid from the nozzle which would result in an uneven spray of non-uniform density. In other words, the liquid is forced through the uid tip under pressure and would pass through the nozzle in the form of a thick narrow stream, but for the air being directed by the shoulders 82 across the stream of liquid which retards-the ow of the same through the nozzle, breaks it up into small particles and prevents its passage through the nozzle as a stream of liquid. This retarding action resulting from what might be termed eddy currents of air, is very importa-nt and gives the advantageous results hereinbefore referred to. It makes the use of a pressure feed cup possible in a device of this character and still gives eiiicient results in the application of these materials. Suchla pressure feed cup is described in the hereinbefore mentioned Downs patent.

Externally the nozzle is provided with an annular iiange 83 providing an annular shoulder 83' for securing the nozzle to the barrel 2 by means of a clamping nut 84 which screw threadedly engages an external threaded portion 85 on the tip end of the barrel 2. With the clamping nut loosened, the nozzle may be rotated to provide any desired angular positioning of the fan slot 82". and thereafter locked in this position upon re-tightening of said nut.

In operation, it being understood that a uid pressure cu-p illustrated in dotted lines in Figure 1 is connected to the extension 54, and that a source of air pressure is connected to the connection 4, thel operator presses the trigger 28 which immediately opens air valve I5 whereby a supply of air under pressure is admitted into the air distributing chamber 8 and from there to the passages I8, Il and 1I into the chamber 88 of the nozzle directly adjacent the fluid tip 8l. Likewise, air is thus admitted to the needle valve chamber I3 and, if the needle valve 25 is open,

into the passages 24 and 12 and thence into chamber adjacent the periphery'thereof. The air in chamber 80, under pressure passes -through the slots 81 in the nozzle tip and also through the holes or passages 8l in partition 19 through the conical passage 11 between the nozzle and the fluid tip and strikes the shoulders 82 of said nozzle in the atomizing chamber V16, being thereby deflected across the open end of the fluid tip, and then out through the fan slot. Since the valve rod 4| has not yet been moved, there is no passage of paint or other liquid, and this does not occur until air under pressure is iiowing through and emerging from the nozzle slot 82. Further movement of the trigger results in movement of the rod 41 and consequently valve rod 4I attached thereto, which moves the valve 4I from its seat in the rear end of the uid tip bore 88 and permits the liquid, which because of -the air pressure thereon has been forced up through passage 58 into chamber `52, to pass through the bore 88 in the uid vtip into the atomizing cylindrical chamber 16 in the nozzle. There, the fluid meets the out-rushing current of air under pressure and is completely broken up and atomized and forced out of the fan slot lpassage 82 in the form of a sheet of misty uid material in proper shape to coat a surface. When the pressure is relieved from the ytrigger the fluid fvalve 4l rst seats,

closing the iiuid passages and preventing the material from dripping or otherwise discharging from the nozzle. After lthis valve has seated Ithe air valve I5 seats, closing oft' the parts of the apparatus from the source of air pressure. This action of lclosing off the air after ythe uid has been cut-01T or air cut-oil lag results in a cleaning action of the air upon -the machined par-ts of the uid tip and nozzle, the continued air flow under pressure after iluid cut 01T serving to whip or blow off residual uid material on said tip and nozzle. The time between the respective cut-ois of fluid and air can be varied to suit any existing conditions by manipulation of the knob 48 to bring the nose l41 of rod 41 nearer vto or further away 'from the trigger 29. Furthermore, the Iprovision of the two separate air passages Il and 24 in the barrel is a distinct advantage. With heavier liquid spray material, both passages are wide open and permit a large volume of air under pressure and properly distributed to atomize the uid emerging from the fluid tip. With thinner fluids, on the other hand, a smaller volume of airI is required for complete atomization of the said fluid, and in such instances the air from passage 24 can be restricted independently by the needle valve 25, or cut oiT entirely when very thin fluids are used. This results in a saving of the operating air stored Iunder pressure, and becomes particularly important if the sources of air supeol ply are tanks oi compressed air used in localities where Dumping equipment is not available. i Furthermore, excess airrparticularly with thin materials would result in objectionable blowing and sputtering at `the nozzle tip. 'Ihis is also avoided by regulating the ow of air in passage 28 by ad- J'ustment of the said needle valve.

My device is not restricted to the use of slot fan type nozzles. In Figures 6-9 inclusive I have illustrated an external or outside mix type of nozzle which may be applied -to the barrel 2 in place of the slot nozzle hitherto described. Except for the external nozzle now to be described all the other elements of the device remain the same, and-corresponding numbers on the said ilgures are identical parts with those of the earlier figures. The external nozzle illustrated consists ofan inner part 88 and an outer part 81. l

Externally, the inner part 88 consists of a substantially conical forward portion -88 superposed upon and integrally formed with a cylindrical por-tion 88 having an annular shoulder or flange 88 at its rear end. The inner part is hollowed or bored out to have an internal conical chamber 8| in the conical portion '88, and a cylindrical chamber 82 contiguoustherewith, and a second cylin- 'drical chamber 83 contiguous with chamber 82 whose internal diameter is so admeasured as to permit entry of air thereto from the outlet of 'the passage 1| only in the barrel 2. The diameter of chamber 482 is so admeasured as to snugly receive the cylindrical Vportion 84 of the iiuid tip so that air may notpass between the walls of said chamber 82 and said portion 8l except through the slots '81, and through holes or perforations 84 provided in and extending in longitudinal direction through the walls about said chamber 82 from the annular shoulder 82' at the junction of the chambers 82 and 83 to the outer wall ort the conical portion 88. Externally, the conical portion is provided with two milled slots or grooves 85 and 88 extending from two diametrlcaliy opposlte openings 84' of holes 8l toward the central opening 81 at theapex of said conical portion. In position of use, themember 881s mounted over the iiuid tip and its rear edge 88' abuts the fiat face 88 of the barrel 2; the nose 88 of the said tip projecting through and somewhat beyond the outer face of saidconical portion 88. 'Ihe diameter of ropening 81 is somewhat larger than that of nose 88 to form an air passage 81 therebetween.

The outer part 81 comprises a substantially cylindrical member having an annular shoulder 88 and a portion 88 of reduced diameter behind said shoulder. Internally the part 81 is bored out to provide a cylindrical chamber |88; a conical portion |8|, those walls abut the walls of the conical portion 88 of the inner part; and a second cylindrical portion |82 whose walls fit snug- `ly over the walls of the cylindrical portion 88 of said inner part. A guide slot |84 in the walls of chamber |82 is adapted to receive a guide pin |88 on the part 88 to prevent relative rotation of the inner and outer parts. The front face of the outer part 81 is provided with two integrally formed longitudinally projecting air jet outlet members |88 and |81 which are diametrically arranged at opposite sides of the central hole |88 therein through which latter the conical portion 88 of the inner part and the nose 88 of the' fluid tip project. These members are arranged at rig-ht angles to the direction of the slots 85 and 88 for a purpose to be presently described. The facing sides |88' and |81' slant outwardly in op posite directions from the bases of the respecf tive members at a suitable angle and are provided With passage outlets |88' and H8' respectively of passages |88 and H8. which latter are Y perpendicular tothe respective slanting faces. Longitudinally extending air passages and ||2 connect the respective passages |88 and ||8 with the chamber space ||8 behind the annular shoulder 88. A suitable clamping nut ||4 having an internal annular ange H8 to engage the said annular shoulder 88, and adapted to b screw-threaded onto the barrel 2 at 88, serves to position the lexternal nozzle on the barrel and to completely surround air space ||3 between the annular shoulder 88 and :the front face 88 of the barrel whereby air from passageway 12 is admitted thereto and directed from the said chamber through the passages and |I2 to outlets |88' and H8' for a purpose to be presently described.

The assembled inner and outer parts 88 andy 81 when mounted on the nozzle end of the barrel serve to form an external type nozzle whereby a fan spray as hitherto described of varying fan spread can be produced. When the trigger 28 is actuated as heretofore described, air is first admitted to the nozzle end of the barrel through the passages Il and 24, 1| and 12, exactly as previously described in connection with the first modincation. 'I'he air from passageway 1| under pressure passes from the outlet of the latter pas- 4 sageway into the chamber 83, partially through the slots 81 to the chamber 8| and out through passageway81aboutthe nose 88. Air also passes from the chamber 83 through the holes 84 and through the milled slots 85 and 88, causing a pair of oppositely directed jets of air to cross the fluid opening in the nose 88. Thesecross-currents intersect the tubular jet ofair emerging from the passageway 81 and set up an eddy current eifect at the liquid outlet of the nose 88 which serves to atomize completely the fluid which now emerges from the fluid tip as the trigger is further pressed by the Operator into full operative position. The cross streams of oppor sitely-directed air from the slots 95 and 88 also flatten the atomized liquid into a fan-shaped spray whose plane is perpendicular to the axial direction of the said slots.

If the needle valve is also open, air under pressure from the source' enters. chamber H3` from the passageway 12 and from there passes through the passages and ||2,.emerg ing through outlets |88' and ||8 as oppositely directed jets of air in the plane of the fan spray and serving to reduce the fan spread. The degree of reduction effected by these last-named jets of air depends upon the volume and velocity of the air emerging from said jets and 'these are controlled as desired by regulation of the needle valve 25. If the latter is wide open, minimum fan spray spread is eiected and if the needle valve is entirely closed, the fan spray spread is at a maximum.

When'the trigger is released by the operator, iluid cut-oir occurs prior to air cut-oir so that, as previously described in connection with the iirst modification, the air jets still continue momentarily and serve to blow or whip of! residual uid material about the fluid tip and nozzle. Likewise, the earlier iluid cut-oil prevents fluid material 6 asaaaae from dripping or otherwisedischarging from the iluid tip. In Figures 10 and l1, I have shown a modiiled form of external 'nozzle adapted to be applied to the barrel 2. Herein the external nozzle ||6 comprises a single part of substantially cylindrical form having an annular shoulder |Il1 and a portion ||8 of reduced diameter. Externally on its front face are two integrally formed lon- 10 gitudinally projecting air jet outlet members ||9 and |20 similar in construction to the members |06 and |01. Members ||9 and |20 are diametrically arranged at opposite sides of the central hole or opening |2| and are provided respectively with the outlets |22 and I 23' oi passageways |22 and 23 at right angles to the slanting faces of these members and which communicate respectively with the longitudinal passagev ways |24 and 25, which latter lead to the chamber |26 behind the annular shoulder ||1.

Internally, nozzle ||6 is provided with a large central bore, the wall of whose rearward portion is so admeasured as to snugly fit about the cylindrical portion 64 of the fluid tip, and whose 25 forward portion of the wall forms the chamber |21 in front of the conical portion 65 of the iluid tip. Behind this cylindrical bore is another of enlarged diameter forming the chamber |26 and, so admeasured in diameter as to admit air there- 30 to from the passageway 1| in the barrel. This external nozzle is mounted over the fluid tip 6|, whose forward nose 66 of smaller diameter than the opening |2|, projects through the latter and slightly beyond the front face of said nozzle. A clamping nut |29 having an internal annular flange |30 to engage the annular shoulder ||1 is adapted to be screwed on the barrel 2 at 85 and to clamp the nozzle thereto.

kOperation of this modified external nozzle is 40 similar to that described above for the firstmentioned external nozzle. When the trigger 29 is operated, air under pressure first ilows from passageways 1| and 12 into the respective chambers |28 and |26. From chamber |26, the air passes through the slots 61 into chamber |21 and out through passageway |2|' of the nozzle about the nose 66 of the fluid tip. From the chamber |26, air flows through passageways |24 and |25 and out through outlets |22' and |23' as a pair of diametrically oppositely-directed jets. These jets of air cross the jet emerging from the outlet 2|' and set up eddy currents which completely atomize the fluid delivered from. the nose 66 of the uid tip and serve to form a fan shaped spray whose plane is perpendicular to the direction of the said air jets from the members H9 and |20. By regulation of theneedle valve 25, the volume and velocity of the latter air jets is controlled to vary the thickness 6o of the fan spray as desired without varying its spread. Preferably, it is best to operate the device when this last-described nozzle is employed with the needle valve 25 somewhat open at all times. The self-cleaning features resulting from 65 earlier cut-off of iluid supply in the device as heretofore described are effected with this type of nozzle for the same reasons hitherto presented with the description of the other modifications.

The respective parts of the device and partic- 70 ularly the fluid tip and nozzle partsare made of metal or other suitable substances which may be machined and tooled to precise dimensions and to have sharp outside edges which latter will prevent accumulation of fluid material and assist 15 the self-cleaning actions described.

While I have illustrated and described only one form of fan slot nozzle, or inside mix nozzle and two forms of external or outside mix" nozzles, it is to be understood that various other forms of nozzles such as fan slot nonies" hav- 5 ing varying widths of fan slots, conical nozzles and other types of outside mix or external nozzles may be used in connection with the device described. A

This device results in a number of advantages, l0 a few of which are as follows. The two air lines in the barrel of the device with needle valve control ln one permit variation of air volume and velocity when slot type nozzles are used, and fan spread and width control when external type noz- 15 zles are used. The increased volume of air led to the nozzle through these double passages effects break-up and complete atomization of the liquid at lower pressures. An even distribution of air is effected by the slots on the fluid tip. In the fan 20 slot nomle. the series of holes in the partition effect an even supply of air to the atomizing chamber. Likewise, with such slot nozzle,the projection ofthe nose of the fluid tip inside the forward cylindrical bore or atomizing chamber in- `2:5 side of the nozzle, forces air to strike the fluid material inside ,the said atomizing chamber to effect proper break-up. With external nozzles, the fan spread may be varied by cutting oil or reducing air flow through one of the two main pas- 30 sageways in the barrel, or the fan thickness may be varied. In addition, the device results in the saving of a substantial amount of material used, operation at greater speed, and on less power.

Furthermore, the device is composed of few wear- 35 ing parts, being made strong and substantial and capable of maximum severe service. Mists, fumes, and the chilling of the liquid material is minimized and a smooth even owing coat free from all blemishes is assured. The ilow of liquidv '4u material is under perfect trigger control and the device is self-cleaning, balanced, light in weight, g

and convenient and unusually easy to operate, disassemble and to clean.`

I claim: 45

l. A paint spraying de vice including a nozzle member having an air passage and a fan shaped slot with which said air passage communicates,

a fluid tip member having a material passage mounted within said nozzle with its end spacedivo from said slot and slots in the side walls of said tip, said device having two air passages terminating one directly adjacent said uid tip and the other at a substantial distance therefrom, and said nozzle member being partitioned and pro- 55 vided with independent passageways for air through the said partitioning whereby air from the said two air passages is uniformly distributed about the iiuid tip member at its outlet end and complete atomization of material owing from the fluid tip is effected.

2. A paint spraying device including a nozzle member having a discharge passage, and comprising an inner and outer part of which the latter is borne upon the inner part, a iluid tip member having a material passage mounted within said inner part with its outlet end extending through both said parts and spaced from said discharge passage, the spacing between said parts forming a plurality of gas chambers and passageways, said device having two gas supplying passageways, one terminating in one of said lchambers and the other in a second of said chambers, said one of said chambers communicating direct- 1y with said discharge passage through passage- 75- ways arranged between said tip member and said inner part, and said inner part having passageways also communicating with said one of said chambers and oppositely directed with respect to said outlet end of said fluid tip member whereby gas supplied from one of said gas supplying passageways to said one oi said chambers is both uniformly distributed about the said outlet end of said uid tip member and directed as streams across the said outlet end to atomize the material flowing from said outlet end and to shape it to a fan spray, and gas jet members on the outer 'part connected by passageways to said second chamber whereby gas from the second of said two gas supplying passageways in said device is ejected from said gas iet members in oppositelydirected streams to vary the spread of said fan spray.

3. A paint spraying device including a nozzle member having an air passage and consisting of an inner and an outer part, a uid tip member having a material -passage mounted within said inner part with its outlet end extending through both said parts and spaced from said air passage, said outer part having a conically bored-out portion, and said inner part having a conical portion adapted to lie in said conically bored-out portion, said inner part having passageways extending through the walls thereof and oppositely directed slots in the conical lportion extending from diametrically opposite passageways therein whereby air is delivered in cross streams over the said uid tip member.

4. A paint-spraying device including a nozzle member having a central air passage adapted to be mounted on said device, a fluid tip member having a material passage mounted within said nozzle with its end projecting through said air passage and spaced from the walls thereof, said nozzle member being so shaped as to form a plurality of air chambers when mounted over said tip member, air jet members on said nozzle communicating'with one of said chambers and two air passageways in said device, one terminating in said last-named air chamber and the other in a second of said air chambers whereby air from the ilrst of said passageways is delivered from said air jet members as Jet streams across the fluid tip member and air from the second of said chambers is delivered through the space between said tip member and the said central air passage to atomize completely the material delivered from said uid tip.

5. A spraying device including a nozzle member having a discharge passageway and an outlet opening with which said discharge passageway communicates, a tip-member having a passage for uid material arranged within said nozzle with its end spaced from said outlet opening, said tip member having slots in its side walls, said device having two passages terminating one directly adjacent said fluid tip member and the other at a substantial distance therefrom, and said nozzle member being partitioned and provided with independent eways for gas each extending through the partitioning, whereby gas from the said two passages passing through the said independent passageways and said slots is uniformly distributed about said tip member at its outlet end and complete atomization of material ilowing from said tip is effected.

6. A spraying device including a nozzle member having a gas discharge passage and comprising an inner and an outer part, a tip member having a passage for iiuid material arranged within said inner part with its outlet end extending through both said parts and spaced from said discharge passage, said outer part having a bored-out portion, and said inner part having a complementarily shaped portion adapted to lie in said bored-out portion, said inner part having passageways extending through the walls thereof and oppositely directed slots in the complementarily shaped portion extending from diametrically opposite passageways therein whereby gas is delivered in cross streams over the said tip member.

7. A spraying device including a nozzle member having a gas discharge passage adapted t0 be mounted on said device, a tip member having a passage for uid material arranged within said v nozzle with its outlet end projecting through said `terminating in said last-named gas chamber and the other in a second of said gas chambers, whereby gas from the first of said passageways is delivered from said gas Jet members as jet streams across the tip member and gas from the second of said chambers is delivered through the space between said tip member and said gas discharge passage to atomize completely the fluid material delivered from said tip.

8. A device, as per claim 7, in which means are provided for independently regulating the flow of gas in one of said two gas passageways.

9. A paint-spraying device including a nozzle member having a discharge passage and a slotted outlet opening with which said discharge passage communicates forming shoulders at the junction of said passage and outlet opening, a iluid-tip member having a passage for spraying material arranged Within said nozzle with its outlet end spaced away from said slotted outlet opening in wardly of said nozzle and comprising a portion intermediate its inlet and outlet ends of substantially larger over-all dimensions than its said outlet end, a partition in the interior of said nozzle member subdividing the latter into separate chambers, said partition having a central bore through which the said portion of said tipmember extends and also having a plurality of communicating passages interconnecting the chambers, and means in said device for effecting the introduction ofgas under pressure into one of said chambers, from which chamber said gas is distributed through the various passageways in said partition into a second chamber and thence about the outlet end of said tip-member in such manner as to eil'ect complete atomization of the material owing therefrom.

AUSTIN H. DOWNS.

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