US2676847A - Spray gun for applying heavy asphalt mastic - Google Patents

Description

April 27, 1954 R. E. KELLEY 2,676,847

SPRAY GUN FOR'APPLYING HEAVY ASPHALT MASTIC Filed April 11, 1951 Patented Apr. 27, 1954 SPRAY GUN FOR APPLYING HEAVY ASPHALT MASTIC Raymond E. Kelley, Snyder, N. Y.

Application April 11, 1951, Serial No. 220,373

1 Claim.

This invention relates to pressure spray guns and is particularly concerned with such guns which are designed and intended for use in spraying thick viscous materials such as heavy asphalt mastic.

It has heretofore been common practice to provide thin coatings of liquids of various compositions and characteristics on surfaces by the use of spray guns and a number of different pressure guns have been devised for and used in the application of such sprayed coatings. There has, however, existed a need for a pressure gun which is adapted for use in applying thick spray coatings of heavy viscous liquids such, for example, as heavy asphalt mastic. This material is a mixture of thick, heavy asphalt with a considerable amount of insoluble filler such as asbestos fiber and is used extensively in waterproofing or damp-proofing concrete and masonry structures, for which purpose it is applied in comparatively thick coats in some cases up to inch in thickness. Because of the large amount of filler and the inherent viscosity of the asphalt, the application of such mastic to surfaces which are to be water-proofed has heretofore required hand application with a trowel or similar tool. Spraying has not been feasible with pressure guns of previous designs since in such guns the mastic is not sufiiciently broken up and is therefore deposited as large lumps or gobs instead of as a fine spray which enters and properly seals the pores in the surface being coated and provides a coating of uniform thickness.

By the present invention there is provided a pressure spray gun which is so designed that even with air supplied at pressures of the order commonly employed viscous materials such as heavy asphalt mastic will be broken up and emitted from the gun as a fine spray instead of being emitted in gobs.

Another object is to provide such a gun which will produce a coating of uniform thickness following the contour of even extremely rough surfaces, the coatingbeing as thick on the sides of deep cavities as it is against the bottoms of these cavities or the exposed surfaces surrounding these cavities.

The invention further comprehends the provision of a pressure spray gun of the type described which is of simple, inexpensive construction, which is" easily adjusted, and which may easily be taken apart for cleaning when necessary.

The construction and further advantages of the pressure gun of the present invention will be more fully understood from. the following description taken in conjunction with the accompanying drawings in which:

Fig. 1' is a longitudinal sectional view of a pressure spray gun constructed in accordance with the present invention;

Fig. 2 is a longitudinal sectional view of the pressure gun illustrated in Fig. 1, the view being taken on line 2-2 of Fig. 1, but with the liquid inlet nipple and delivery tube being shown in plan;

Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 1; and

Fig. 4 is a transverse sectional view taken on the line d@ of Fig. 1.

As illustrated, the pressure spray gun of the present invention comprises a body II which is essentially a lateral fitting having a cylindrical through passage I2 and a cylindrical lateral passage I3 communicating at one end with the through passage I2 and extending to the exterior of the body I I through an integra1 boss it. The left end of the passage i2, as viewed in Fig. 1, is provided with screw threads It in which there is threadedly engaged one end I7 of a degree elbow fitting I8. The other end it of the fitting i8 is provided with interior threads and has secured therein by said threads a liquid inlet pipe 20.

The end I i of the elbow fitting I8 has mounted therein as by threads ii an elongated liquid de-= livery tube 22 which is arranged concentrically within the cylindrical passage I2 and extends outwardly through the right end of the body H. A fitting such as a nipple 24 is threadedly engaged in the outer end of the boss I4 and has connected thereto, by suitable means such as threads, an air inlet pipe 25.

The cylindrical through passage I2 in the body it is provided at its right end, as viewed in Fig. 1, with screw threads 26 in which there is engaged one end of an externally threaded, tubular mixing shell 27. The shell 21 extends outwardly from the body H and is provided with a cylindrical bore 28 into which the outer end of i the liquid delivery tube 22 extends in concentric arrangement with the open, outer end 29 of the tube 22 being adjacent the frusto-conical end Wall 39 of the shell. An axial outlet 32 is pro vided through the end wall 3%} and a plurality, preferably at least four, equally spaced auxiliary outlets 33 of smaller diameter than the outlet 32 are provided in the conical face of said wall in a circle concentric with the axial outlet. The shell 27 may be axially adjusted by turning it in or out of the body I I to vary the distance of the end wall 3i! from the tube end 29 and thereby to vary the flow of air andliquid through the auxiliary ports or outlets 33.

A nozzle 34 having an internally threaded bore 36 .is threadedly engaged on the outside of the mixing shell 21. At its inner end the bore 36 is reduced in diameter, the walls of the bore being internally bevelled at substantially the same angle as that of the frusto-conical end wall 3i! of the mixing shell 21. An axial outlet passage 31, which is elongated so that its length is substantially greater than its diameter, provides communication between the inner end of the bore 36 and the inner face of a depression 33 formed in the outer end of the nozzle 34.

It will be seen that the construction hereinabove described provides a pressure spray gun in which mixing of air with the viscous liquid material being sprayed takes place in two separate mixing chambers. The first mixing chamber is in the end of the bore 28 of the mixing shell 27 between the open end 29 of the liquid delivery tube 22 and the end wall 3%, while the second mixing takes place within the nozzle 35 at the inner end of the bore 36.

In using the improved pressure gun of the present invention the viscous liquid, such as heavy asphalt mastic, is supplied through the inlet pipe 2@ and flows through the elbow fitting i8 and the elongated liquid delivery tube 22. The viscous liquid may be fed to the gun by any suitable means such as a pump, air pressure or gra vity. At the same time air under pressure is admitted to the pressure gun through the pipe 25. The compressed air flows through the passage it into the passage l2 of the body ii and then through the annular space between the delivery tube 22 and the mixing shell 21 to the end of the bore 28 of the shell.

Since the mixing shell 27 is threadedly engaged in the body ii, it is axially adjustable with respect to the liquid delivery tube 22 and the frusto-conical end wall 30 is preferably so positioned with respect to the end 29 of the tube that some air is mixed with the viscous liquid which passes from the tube 22 into the first mixing chamber provided in the shell 27 and through the extension of said mixing chamber consti tuted by the axial outlet 32 of the shell, while the remaining portion of the air passes from the annular space around the tube through the auxiliary outlets 33 into the bore 36 of the nozzle 3% where it mixes with the viscous liquid whi h has entered the bore 36 through the axial outlet 32. Thorough mixing of the air and liquid takes place in the second mixing chamber and the aerated mixture is forced through the elongated outlet passage 3.1, emerging at the outer end of the passage as a spray in which the viscous li uid is in finely divided form which may be deposited on surfaces to give an even, smooth coat.

The concavity or depression 38 in the outer end of the nozzle 34 has a tendency to confine the spray and form. it into a cylindrical stream in which spattering is minimized and thereby facilitates accurate depositing of the spray material. Locknuts ll and d2 threadedly engage on the outside of the tubular mixing shell 2! and, respectively, secure the shell in adjusted position with respect to the liquid delivery tube 22, and the nozzle 34 in adjusted position with respect to the end wall 30 of the mixing shell 21.

By the practice of the present invention, the heavy asphalt mastic is applied as a coating of uniform thickness on surfaces which are extremely irregular as well as smooth surfaces, which coating of uniform thickness closely follows the contour of irregular surfaces including the sides of deep and irregular depressions as well as the bottoms and rims thereof. With present spray guns, when used with heavy mastic onirregular surfaces, 2. heavy deposit is made on the bottoms of deep depressions as well as on the surface from which the depression extends but little, if any, of the heavy mastic is deposited on the sides of the depression. This condition is corrected with the use of the gun embodying the present invention.

It will be evident that the pressure spray gun of the present invention provides for the spraying of viscous liquids such as heavy asphalt mastic and similar materials in a highly satisfactory and efficient manner. It will also be seen that the construction .of the pressure gun is simple and that it may be readily adjusted in accordance with factors such as the temperature, viscosity and pressure of the fluids to provide proper mixing thereof and a uniform spray of finely divided liquid particles;

it will be understood that numerous modifications and variations in the construction of the pressure gun herein described may be made as occasion arises without departing from the spirit of the invention. It is, therefore, intended that the invention shall not be considered limited to the specific embodiment shown in the drawings and described herein, but that it shall be inter-- preted broadly and restricted only as may be re quired by the scope of the appended claim.

I claim:

A pressure gun for spraying heavy asphalt mastic comprising a body having a through passage and a lateral passage, said body at one e d of through passage being provided w means for attaching an inlet pipe thereto, s lateral passage communicating at its inner e with said through passage and said body at outer end of said lateral passage being provided with means for attaching an inlet pipe thereto, a tubular mixing shell secured to said body at the other end of said through passage and extending outwardly from said body, said shell co1nprising a bore communicating with said through passage and having, at its cuter end, a first ing chamber, a frusto-conical end wall provide with an axial outlet from said mixing cham a plurality of auxiliary outlets spaced l'ur dially from said axial outlet, a mastic delivery tube mounted in said body and communicating at one end with the inlet to said through pas-- sage, said tube projecting outwardly from said body into the bore of said shell and having other .end spaced from said outlets from 1 bore, said shell being axially adjustable with r spect to said tube, and a tubular nozzle moui on said shell and axially adjustable thereon, nozzle having a second mixing chamber and an outlet passage providing communication between said chamber and the outer end of said nozzle.

References Cited in the file of this patent 174,904 France Mar. 26, 1915

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