US2960275A - Flame spray gun - Google Patents

Description

Nov. 15, 1960 H. WOLF FLAME SPRAY GUN Filed April 26, 1960 2 Sheets-Sheet 1 M/a/ENTa/Q WOLF Nov. 15, 196 0 H. WOLF 2 2,960,275

FLAME SPRAY GUN Filed April 26, 1960 2 Sheets-She et 2 ATTOZME PLANE SPRAY GUN Heinrich Wolf, lltisstrasse 66, Koln-Bickendorf, Germany, assignor to Hermine Wolf, ne Freudenthaler, Koln-Bickendorf, Germany Filed Apr. 26, 196i Ser. No. 24,789

Claims priority, application Germany Apr. 29, 1959 7 Claims. (Cl. 239-85) The present invention relates to a flame spray gun for combustible fluids, paints, and enamels, and particularly also for thermoplastics which are hardened by heating of their hardening agents. More particularly, the invention relates to a flame spray gun which is provided with a nozzle head comprising an outlet nozzle for the fluid to be sprayed and an air nozzle surrounding the fluid nozzle, and in which this nozzle head is, in turn, surrounded in a spaced relation by a heating jacket which is open toward the front and rear.

In similar flame spray guns of previous design, the material which is sprayed comes into contact with an open flame immediately after leaving the spray nozzles. Consequently, there is a considerable danger that the material will ignite and burn up. Furthermore, in these prior flame spray guns it is almost unavoidable that the flame will be taken along by the high-velocity jet of air which surrounds the sprayed material and that it will therefore be separated and extinguished. Although when operating with a considerable heat output, this may be avoided by reducing the velocity of the air current, such reduction entails the disadvantage that the material will no longer be sufliciently atomized. Thus, when operating with an air current of a sufficient velocity in order to attain a proper atomizing of the material, only a small heat output will be attained. When spraying with such a spray gun it is therefore necessary to adjust the velocity of the air current as well as the velocity of the fuel gas continuously relative to each other. Since the flames of the burner are partly unprotected, they may also be easily blown out by a strong wind when working outside. Furthermore, it often occurs in such spray guns that the nozzle head will be heated by the heat radiating from the open flame, with the result that the material to be sprayed will already be hardened within the nozzle. This causes considerable unnecessary work and long interruptions since the entire spray gun must then be taken apart and cleaned.

It is an object of the present invention to provide a flame spray gun which will overcome all of the abovementioned disadvantages.

A further object of the invention is to provide a flame spray gun in which the material to be sprayed will be heated not directly by an open flame, but indirectly through radiation.

In order to attain these objects, the invention provides the flame spray gun with a slip-on heating jacket which may be attached upon the front end of the tubular housing of the gun and then surrounds the nozzle head in a spaced relation thereto. This heating jacket forms a combustion chamber or burner and it consists of a pair of spaced tubular members within each other which are connected to each other at their rear ends by covering plates which are bent so that all of them together form an annular louver. It is further advisable to provide gas nozzles at both sides of the front part of the tubular housing surrounding the nozzle head of the gun, and to adjust these gas nozzles, so as to blow the gas in the same general direction into the slots between the louverlike covering plates at the rear end of the combustion chamber within the heating jacket. By the combined arrangement of the gas nozzles and the louverlike covering plates, a vortex of flames which is directed toward the front is produced in the combustion chamber. The necessary combustion air for these flames is drawn into the combustion chamber by an injector eflect.

Another feature of the invention consists in providing a cooling-air nozzle at the inside of the tubular housing and in a position so as to blow a current of cooling air into the annular space between the housing and the head of the gun so that the cold air emerging from the front end of the housing will cool the nozzle head and will thereby be heated so that it will then serve as additional heating air. The air and gas conduits are preferably mounted at the inside of the tubular housing and inside of the handle of the gun, and they should be adjustable by valves of a suitable kind. These valves are preferably provided within a valve block which is secured by a screw on the lower end of the handle and also carries the fittings for connecting the air and gas hoses thereto. The valve for regulating the air supply for the atomizing current is preferably designed so as also to regulate the coolingair current, and both currents are supplied through the same air hose and connection fitting on the lower end of the gun handle.

These objects, features, and advantages of the present invention will become further apparent from the following detailed description thereof, particularly when the same is read with reference to the accompanying drawings, in which Figure 1 shows a longitudinal section of the flame spray gun according to the invention;

Figure 2 shows a cross section taken along line -II-II of Figure 1; while Figure 3 shows a perspective rear view of the heating jacket or burner.

As illustrated in the drawings, the housing of the flame spray gun according to the invention consists of a tubular member 1 which is secured at a suitable angle to a handle portion 2 of an oval cross section. The nozzle head 4 of the gun is mounted within this tubular housing 1 in such a manner that an annular channel 8 for the passage of cooling air is formed between nozzle head 4 and the tubular member 1. Nozzle head 4 is provided with a channel 10 through which the fluid to be sprayed is supplied. This channel 10 extends into a nozzle 11 which is screwed into the front end of nozzle head 4, and is provided with a needle rod 12. Needle rod 12 is adjustable in the axial direction within channel 10 and nozzle 11 and in cooperation with the latter it forms a needle valve. Behind nozzle head 4, the shaft of needle rod 12 is threaded and carries a pair of knurled nuts 13 which may be adjusted to different positions along rod 12. A coil spring 15 surrounding needle rod 12 rests on a removable cap 16 which closes the rear end of housing 1, and it acts with its front end against nuts 13 to urge needle rod 12 forwardly to maintain the needle valve in the closed position. Housing 1 further has on its upper side a bearing 17 in which a lever 14 is pivotably mounted which extends transversely through the housing and through a slot 17' in the lower side thereof at a point opposite to bearing 17. When the outer end of lever 14 which forms a trigger is pulled back, the upper part of the lever will engage with nuts 13 to draw needle rod 12 toward the rear against the action of spring 15 to open the needle valve to any desired extent. A setscrew 18 extends through end cap 16 into housing 1 and permits the extent of the movement of needle rod 12 to be adjusted.

The front end of nozzle head 4, which extends centrally within the tubular housing 1, is also provided with outer screw threads upon which a nozzle cap 29 is screwed so that between the inner surface of this nozzle cap and the outer surface of fluid nozzle 11 an annular channel 21 is formed which terminates into an annular nozzle opening around the central opening of nozzle 11 for supplying the necessary jet of air to carry and atomize the liquid which is ejected through nozzle 11. This channel 21 communicates with a bore within the wall of nozzle head 4, and bore 25 is, in turn, connected to the upper end of a tube 22 which extends first through housing 1 and then downwardly through the inside of the handle part. 2. The lower end of handle 2 carries a valve block 3 which is secured to the handle by a screw 23 and contains a conical valve cock 24 for regulating the current of compressed air which is supplied through the connecting fitting 26. In the center of handle 2, a tube 23 is mounted which terminates at its upper end within housing 1 into a nozzle 29 through which a jet of cooling air is blown. The shaft of screw 23 has a central bore, the inner end of which extends through the wall of the shaft toward one side and com,- municates through a channel 27 in valve block 3 with valve cock 24, which is thus capable of regulating the air supply to the atomizing nozzle 21 and to the coolingair nozzle 29. This nozzle 29 is disposed in such a position Within housing 1 that the air current ejected therefrom will pass through the annular cooling-air channel 8 and along the nozzle head 4 so as to cool the latter. Since this cooling air Will thereby be heated, it will serve in front of nozzle head 4 as a supplementary hot-air current.

The front end of the tubular housing I carries a heating jacket 30 which is removably fitted thereon and consists of two tubular parts 5 and 6 which are disposed coaxially within each other and are rigidly connected to each other at the rear end by an annular plate into which a plurality of radial cuts are made by stamping so as to form a series of inclined, louverlike deflecting plates 7. As illustrated in Figure 2, at both sides of the part of the tubular housing 1 which surrounds nozzle head 4, gas nozzles 31 are provided which are disposed in such a position that the nozzle openings thereof are adapted to blow currents of gas in the same general direction into the slots 32 which are formed by the deflecting plates 7, so that a strong vortex of gas will be ejected into the combustion chamber 9. The required amount of air for the combustion of the gas is provided by the injector action of heating jacket 3t Due to this vortex formation of the gas current, each flame which is formed will travel for a considerable distance Within the combustion chamber 9 which is defined by the tubular parts 5 and 6. The whirling flames or the vortex of the combined flames will therefore never pass out of the combustion chamber 9.

The required fuel gas is supplied to gas nozzles 31 through an inlet tube 33 which extends along the inside of handle 2 and housing 1. The lower end of inlet tube 33 is connected to a passage in valve block 3 which contains a valve screw 34 for regulating the gas supply and terminates in a connecting fitting 35. The feed conduits 36 connect the gas nozzles 31 with the inlet tube 33 and also serve for suspending the nozzle head 4 within the tubular housing '1. Nozzle head 4 is further provided with a screw socket 19 to which a container (not shown) holding the material to be sprayed is to be connected.

If the fuel gas is passed through gas nozzles 31 into the combustion chamber 9 and the mixture of gas and air is then ignited, it will burn within the combustion chamber along a closely wound spiral course with the result that the inner tubular part 6 will be quickly heated to incandescence. This inner tube 6 which then glows dark red heats the jet of material passing from nozzle 11 by radiation. Since the flames are confined within the combustion chamber 9, they will burn steadily, and even in a strong wind there will be no danger that they will be blown out.

Since the heating jacket 30 is mounted on the tubular housing 1 separately from the gas nozzles 31, it may be easily removed, permitting an easy access to the gas nozzles 31, the nozzle cap 20, and the liquid nozzle 11.

Although my invention has been illustrated and described with reference to the preferred embodiment thereof, I wish to have it understood that it is in no way limited to the details of such embodiment, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, What I claim is:

1. In a flame spray gun for combustible fluids having a tubular housing and a handle thereon, a nozzle head at one end of said housing having an outlet opening for supplying the fluid to be sprayed and anannular outlet opening surrounding said first outlet opening for supplying a current of air, and a heating jacket surrounding said nozzle head in a spaced relation thereto, said heating jacket comprising a pair of tubular members coaxially within and spaced from each other, and a plurality of louverlike deflecting plates having intermediate radial slots securing said tubes to each other at the rear end thereof and forming a combustion chamber between said tubes, and means disposed behind said deflecting. plates for supplying a fuel gas under pressure through said slots and along said deflecting plates so as to form a vortex of gas within said combustion chamber.

2. In a flame spray gun as defined in claim 1, in which said heating jacket forms an element separate from the other parts of said gun and is adapted to be fitted upon and easily removed from the front end of said tubular housing.

3. In a flame spray gun as definedin claim 2, in which said heating jacket consists of a single piece of material comprising said tubular members and an annular plate at the rear end integrally connecting said members and having stamped portions therein forming said deflecting plates and radial slots.

4. In a flame spray gun as defined in claim 1, in which said heating jacket is mounted on the front end of said tubular housing, said gas supply means comprising gas nozzles at both sides of the part of said housing surrounding said nozzle head, said gas nozzles being disposed so as to blow the gas in the same direction relative to the center of said jacket into said radial slots.

5. In a flame spray gun as defined in claim 1, in which a cooling-air nozzle is provided in said tubular housing and adapted to blow a current of cooling air along said nozzle head.

6. In a flame spray gun as defined in claim 5, in which all air and gas conduits required for the operation of said gun are disposed within said housing and handle, gas and air connections on said handle, and valve means on said handle for regulating the supply of gas and air to said gun.

7. In a flame spray gun as defined in claim 6, in which said valve means are provided within a single valve block, and means for removably securing said valve block to the lower end of said handle and to the lower ends of said air and gas conduits therein, said valve means comprising a single valve for regulating the air for said annular nozzle opening and said cooling-air nozzle.

References Cited in the file of this patent UNITED STATES PATENTS 1,756,381 Pahl Apr. 29, 1930 2,794,677 Collardin et al. June 4,

Images