US2070695A - Spray head - Google Patents

Description

Feb. 16, 1937. R. w. TRACY 2,070,695

SPRAY HEAD Filed Da e. 9, 19 35 Robe/7 W Facy Patented Feb. 16, 1937 UNITED STATES SPRAY HEAD Robert W. Tracy, Toledo, Ohio, assignor to The De Vilbiss Company, Toledo, Ohio, a corporation of Ohio Application December 9, 1935, Serial No. 53,601

12 Claims.

This invention relates to spray painting apparatus, and is more particularly directed to the spray-head or cap portion of such apparatus.

The invention utilizes a plurality of pairs of atomizing jets acting on the main surface coating stream to break up the heavy central particles of the stream, in combination with flattening jets to shape the stream into an elliptical crosssection.

The primary object of the present invention is the provision of a cap having provision for discharging a plurality of air jets acting on the spray discharge of'the paint gun to completely atomize and shape the spray.

Another object of the invention is the provision of a plurality of pairs of opposed atomizing jets acting on the spray discharge of a paint gun to produce a complete atomization of the heavy central particles of the spray before the stream is flattened to its final shape.

Other objects and advantages of the invention will become apparent as the description proceeds, reference being had to the accompanying drawing, in which- Figure l is a perspective view of a spray-head or cap having atomizing and flattening jets issuing therefrom and disposed in accordance with my invention, and Figs. 2, 3 and 4 are modified forms of the invention disclosing various combinations of air streams to form the atomizing and flattening jets.

Referring to the drawing, and particularly to Fig. l, the present invention is disclosed in connection with a cap having a body I from which the usual supplemental air discharge horns 3 and 4 project. The body I is provided with the usual central liquid discharge orifice 6 and central air orifice 8 concentric therewith. Thus, the air supported liquid stream issues from the gun in the usual circular stream form.

The spray stream is first impinged and atomized by air streams I0 and I I issuing from orifices I2 and I3 in the face of the cap. The streams from these orifices are each at a wide acute angle 5 relative to the line of discharge, so that the air,

pierces the stream and breaks up the heavy central particles. The shape of the resulting stream is analogous to an hour-glass.

The stream is further atomized and shaped by 5 a second pair of atomizing jets I4 and I5 acting on the stream and issuing from orifices I 6 and I! formed in the face of the cap in a plane substantially at right angles to the plane of the first-mentioned atomizing jets. It will be seen that the hour-glass shape of the stream is here dispersed and re-formed, so that the resulting stream is elongated in a plane at right angles to the elongation imparted by the jets I0 and I I.

I The atomization of the stream is thus considerably accentuated so that it is possible tospray 5 liquids having a relatively high viscosity without spattering caused by the impingement of relatively large liquid particles on the surface being coated.

The final flattening and shaping of the stream 10 is imparted by opposed flattening jets 20 and 2I impinging on the stream in a plane at right angles to the plane of the second set of atomizing jets I 4 and I5, and in substantially the same plane as the first atomizing jets I0 and II. Again, the 15 major axis of the elliptical stream section is rotated substantially 90, so that the stream section is elongated in a horizontal plane in Fig. 1.

In the form shown in Fig.2, primary atomizing jets 22 and 23 strike the spray stream at a wide 20 acute angle similar to the jets I 0 and II in Fig. 1. Secondary atomizing jets 25, 25, act on the stream and each is formed by the convergence of angularly disposed air streams 26 and 21 issuing from orifices 28 and 29 in the face of the cap. In 25 the interest of clarity, the reference numerals are applied only to those orifices and streams on one side of the cap, but it will be appreciated that in each instance the parts are duplicated on each side of the main spraystream. The orifices 28 30 and 29 are in substantial alignment in a plane I diametrical to the spray stream discharge and at right angles to the plane of the primary atomizing jets 22 and 23. The discharge from the outermost of the two secondary orifices 29 is directed 5 toward the stream at a higher angle than the cooperating orifice, in this instance 28, so that the air streams issuing from these two orifices combine to form an elliptical atomizing jet 25, which is elongated in a plane at right angles to 40 the plane of the hour-glass formation imparted to the spray stream by the primary atomizing jets 22 and 23. The enveloping action of these jets prevents undue dispersion of the particles of the spray stream, and permits a higher angle of convergence of the primary atomizing jets. The secondary atomizing jets 25 act to bring together the ends of the stream which have previously been elongated by the primary atomizing jets 22 and 23, and so form the stream into a compact but so highly atomized mass. The stream is then flattened to its final shape by the opposed flattening jets 20 and 2i similar to the manner indicated'in Fig. 1.

In the modification shown in Fig. 3, the primary atomizing jets 30 are formed by the convergenc of a plurality of air streams 3| and 32 I and toward the main liquid stream, so that the resultant jet 30 is elliptical in cross-section with its elongation in the direction of spray discharge. The eiiect of this elongation is to produce a knifelike penetration of the jet 30 on the spray discharge, so as to completely atomize a stream of viscous liquid. In this modification, the penetration may be made quite complete since the secondary atomizing jets are flattened or elliptical in a plane at right angles to the resulting spray stream and serve to envelope the stream and bring the ends together and thus'prevent dispersion of the outer particles. The secondary atomizing jets designated 35 are formed in the same manner as the modification shown in Fig. 2 by the convergence of a pair of air streams 36 and 31 issuing in substantially the same horizontal plane and meeting to form the flattened secondary atomizing jet 35. The stream is finally shaped by the flattening jets 20 and 2|, which strike the stream in a plane at right angles to the secondary atomizing jets.

In the form shown in Fig. 4, the primary atomizing jets 40 are formed in a manner similar to that shown in Fig. 3, so that the knife-like penetration of the primary atomzing jets is maintained. In case of extremely viscous liquids, it is desirable to provide a second pair of atomizing jets 4| formed by the convergence of separate streams 42 and 43 issuingirom spaced orifices .44 and 45 in the face of the cap. The orifices 44 and 45 are disposed in substantially vertical alignment and discharge toward the spray stream at different angles, so that the streams converge to form the resultant'knife-like jet 4|, which penetrates the stream in a plane at right angles to the penetration of the primary atomizing jets 40. It will be seen that the ends of the atomizing stream are brought in by the second pair of atomizing jets, so that the stream .is again a compact mass of highly atomized particles. The final flattening andshaping of the stream is again accomplished by the flattening jets 20 and 2!.

From the foregoing description, it is apparent that in each instance the air supported streani oi coating liquid is acted upon successively by two distinct pairs of atomizing jets, and by a pair oi! suitable flattening jets. In each instance the angular disposition of the jets is such that each succeeding pair of jets flows towards the stream in a plane rotated substantially from the plane of the immediately preceding jets or the last jets acting on the stream, so that no two successive pairs of, jets act in the same plane. expressly understood that modifications in the relative angular positions of the several jets may be made within the scope of the present invention.

It will be appreciated that the angular disposition of the several jets disclosed in each modification ismerely illustrative, and has been exaggerated in some instances in the interest of clarity. Obviously, the angles may be varied throughout a wide range without departing from the invention as defined in the appended claims.

Having thus described my invention, what. I claim as new, and desire to secure by. United States Letters Patents, is:

1. A spray head of the class described having provision for discharging an air supported stream It should be of coating liquid, and having provision for discharging two distinct pairs of atomizing jets, the jets of each pair being disposed in a single plane and a coplanar pair of flattening jets, acting on the stream of coating liquid in succession, the direction of flow of each pair of jets being in planes removed substantially 90 from the plane of the immediately preceding pair of jets.

2. A spray head oi the class described having provision for discharging an air supported stream of coating liquid, and having provision for discharging two distinct pairs of atomizing jets, and a pair of flattening jets acting on the stream of coating liquid in succession.

3. A spray head of the class described having provision for discharging an air supported stream of coating liquid, and having provision for discharging a plurality of distinct pairs of atomizing jets and a pair of flattening jets acting on the stream of coating liquid in succession, each of the jets of at least one of said pairs of atomizing jets being elliptical in cross-section.

4. A spray head of the class described having provision for discharging an air supported stream of coating liquid, and having provision for discharging a plurality of distinct pairs of atomizing jets and a'Qair oi. flattening jets acting on the stream of coating liquid in succession, each of the jets of at least one of said pairs of atomizing jets being elliptical in cross-section and elongated in the direction of discharge ofthe stream of coating liquid.

5. A spray head of the class described having provision for discharging an air supported stream of coating liquid, and having provision for discharging a plurality of distinct pairs of atomizing jets and a pair of flattening jets acting on the stream of coatingliquid in succession, the jets of one of said pairs of atomizing jets being elliptical in cross-section and elongated in a plane at right angles to the stream of coating liquid.

6. A spray head of the class described havingprovision for discharging an air supported stream of coating liquid, and having provision for discharging two distinct pairs oi. atomizing jets and a pair of flattening jets acting on the stream of coating liquid in succession, the jets of both of said pairs of atomizing jets being elliptical in cross-section, one being elongated in a plane at right angles to the stream of coating liquid and the other being elongated in the direction of discharge of said stream of, coating liquid;

7. A spray head of the class described having provision for discharging an air supported stream of coating liquid, and having provision for discharging two distinct pairs of atomizing jets and a pair of flattening jets acting on the streamof coating liquid in succession, the jets of both of said pairs of atomizing jets being elliptical in cross-section and elongated in the direction of discharge of the stream of coating liquid.

8. A spray head of the class described having provision for discharging an air supported stream of coating liquid, and having provision for dischargingtwo distinct pairs of atomizing jets and a pair o1 flattening jets acting on the stream of coating liquid in succession, each jet of at least one of said pairs 01' atomizing jets being formed by the convergence, on each side'of the stream of coating liquid, of a plurality of diflerently directed air streams which merge to form a jet of elliptical cross-section.

9. A spray head-of the class described having provision for discharging an air supported stream 75 oi. coating liquid, and having in combination, pairs of atomizing air orifices adapted to emit separate pairs of atomizing air streams acting on the stream of coating liquid, said pairs of atomizing orifices being disposed in planes substantially at right angles. to each other, and separate supplemental air orifices adapted to emit, on each side of the stream of coating liquid, flattening and enveloping jets of air striking said stream after said atomizing jets have acted upon the stream.

10. A spray head of the class described having provision for discharging an air supported stream of coating liquid, and having provision for discharging a pair of atomizing jets and a pair of flattening jets acting on the stream of coating liquid in succession, said atomizing jets being formed by the convergence on each side of the stream of coating liquid, of a plurality of difierently directed air streams which merge to form a jet of elliptical cross-section.

11. A spray head of the class described having provision for discharging an air supported stream or coating liquid, and having provision for discharging a pair of atomizing jets and a pair of flattening jets acting on the stream or coating liquid in succession, said atomizing jets being formed by the convergence on each side of the stream of coating liquid, of a plurality of differently directed air streams which merge to form a jet of elliptical cross-section elongated in the direction of discharge of the stream of coating liquid.

12. A spray head of the class described having provision for discharging an air supported stream of coating liquid, and having provision for dis-' charging a pair of atomizing jets and'a pair of flattening jets acting on the stream or coating liquid in succession, said atomizing jets being formed by the convergence on each side of the stream of coating liquid, of a plurality of differently directed air streams which merge to form a jet of elliptical cross-section elongated in a plane at right angles to the stream 0! coating liquid.

ROBERT W. 'I'RACY.

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