US3059860A

US3059860A - Atomizing nozzle assembly

Info

Publication number: US3059860A
Application number: US69171A
Authority: US
Inventors: Hohn Karl-Heinz
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-11-17
Filing date: 1960-11-14
Publication date: 1962-10-23
Anticipated expiration: 1979-10-23

Description

Oct. 23, 1962 KARL-HEINZ HOHN 3,059,860

ATOMIZING NozzLE ASSEMBLY Filed Nov. 14, 1960 rates This invention relates to liquid spray apparatus, and, more specifically, to a nozzle arrangement for such apparatus in which a liquid is atomized by an injector effect.

My improved nozzle assembly consists generally of a hollow or tubular air nozzle and a liquid nozzle arranged concentrically within said air nozzle. By the flow of air or other gaseous medium through the air nozzle, liquid is drawn through the liquid nozzle and is atomized and mixed with the air so that an evenly `distributed and highly atomized spray is emitted by the nozzle arrangement.

My improved nozzle assembly is useful in spraying many dierent types of liquids, such as paint, varnish and other finishes, disinfectants, insecticides and the like.

In apparatus of the kind heretofore known in the art, the air nozzle as well as the liquid nozzle are generally attached by screw threads to the orifice of the apparatus. As already explained, the air flowing through the air nozzle generates a low or reduced pressure in front of the liquid nozzle. The value of the low or reduced pressure determines the degree of atomization and is dependent, at least in part, on the size of the clearance, that is the annular space, between the liquid nozzle and the air nozzle. In order to attain an even distribution and atomization of the liquid, it is, therefore, important that exact concentricity be maintained between the liquid nozzle and the air nozzle and that the annular space be of the same size around the entire periphery. Increased accuracy with respect to concentricity is required in the case of nozzles of smaller diameter.

In the nozzle arrangements heretofore known exact co-axiality can be obtained only with considerable diiiiculty as the air nozzle and the liquid nozzle are separately threaded to the apparatus and it is almosst impossible to make two screw threads exactly co-axial to each other as required for this purpose. Therefore, it is necessary to take steps to center the nozzles with respect to each other, and this is particularly true in the case of spray apparatus used for graphic purposes. Centering in this fashion requires complicated devices which have to be operated by skilled employees with the result that it can generally be accomplished only in the factory in which the nozzle assembly is produced. This means that the user encounters difficulties when the nozzles have to be disassembled and replaced, which is frequently necessary, for instance, if the nozzles are dirty or if a nozzle of another size is necessary. Under these circumstances, the apparatus has to be sent to the factory for adjustment.

It is the main object of the present invention to overcome the difficulties heretofore encountered and to provide a nozzle arrangement in which the nozzles are maintained in concentric relationship in a simple and improved manner and the liquid nozzle can be readily exchanged and `replaced without affecting the centering of the liquid nozzle in relation to the air nozzle Other objects of the invention will become apparent when reading the following description in connection with the drawing, in which:

FIG. l is a longitudinal sectional view of one form of nozzle arrangement known in the prior art;

FIG. 2 is a cross-sectional View taken along line 2-2 of FIG. 1;

FIG. 3 is a longitudinal sectional view of one form of nozzle arrangement embodying the present invention;

FIG. 4 is a cross-sectional view in the direction of the arrows on the line 4 4 of FIG. 3;

latent ice FIG. 5 is a longitudinal sectional view of another form of nozzle arrangement embodying the invention; and

FIG. 6 is a cross-sectional view in the direction of the arrows on the line 6-6 of FIG. 5.

In the known arrangement according to FIGS. 1 and 2 the body of the apparatus 1 is provided with an external thread 2 for connecting the air nozzle 3 and with an internal thread 4 for receiving the liquid nozzle 5. Both

threads

2 and 4 must be exactly co-axial in order to obtain an annular gap 6 between liquid nozzle 5 and an air nozzle 3 which is of the same size around its entire circumference. This can hardly be accomplished because an exact co-axial manufacture of both threads in the required precision without any tolerance is for all practical purposes, impossible. Therefore, it Igenerally happens that the liquid nozzle is eccentric with respect to the air nozzle and that the annular space between the nozzles is smaller at one portion of the annulus than another, as shown in FIG. 2. The cross-sectional area of gap 6 may be reduced to zero at a point of contact as shown, and this results in considerable difference in pressure reduction around the liquid nozzle 5 with consequent uneven atomization of the liquid. The necessary adjustment can be made only by skilled workmen with special tools and, generally speaking, the user is unable to make these adjustments.

The present invention overcomes these diiculties in that the liquid nozzle is not fixed to the apparatus but is in guided engagement with the air nozzles so that a concentric relationship is maintained at all times and the liquid nozzle may be readily exchanged or replaced with relatively non-skilled personnel as no adjustment of the parts is thereafter necessary.

In the embodiment shown in FIGS. 3 and 4, the air nozzle 13 is, as in FIG. l, screwed to the body 11 by thread 12. The inner surface 17 of the air nozzle is conical in shape and the :liquid nozzle 15 is in contact with the conical surface along a plurality of contact lines Ztl. The Contact lines are preferably evenly spaced and are preferably at least three in number and they form mantel or envelope lines of a cone having the same apex angle as the conical inner surface of the air nozzle. Thus, the liquid nozzle centers itself completely and automatically and is pressed against the supply line 18 when the air nozzle is screwed to the thread 12. A sealing ring 19 is preferably interposed between the liquid nozzle and the ysupply line 18 to insure sealing engagement between these parts. Air passageways 21 of uniform cross-sectional size and area are formed between the contact lines 10 and serve as passages for distributing the air.

In the assembly shown in FIGS. 3 and 4, air enters the air nozzle from the apparatus through channel 22 which is connected to a source of air under pressure and liquid enters the nozzle from the apparatus through channel 18. Due to the fact that the air passageways or cavities Z1 between the nozzles are of uniform, crosssectional area, the air is evenly distributed around the outer end of the liquid nozzle 15 with the result that there will be uniform reduction in pressure and uniform atomization of the liquid from the liquid nozzle.

Naturally, it is possible to use point contact rather than line contact between the liquid nozzle and air nozzle in order to obtain concentricity and, under those circumstances, the contact point should -be arranged along lines on a projected conical envelope for the nozzle. It is likewise po-ssible to make the external surface of the liquid nozzle in the form of a complete cone mantel or envelope and to provide the contact lines or points on the internal surface of the air nozzle.

In the embodiment shown in FIGS. 5 and 6, the liquid nozzle 35 is guided in a separate cylindrical member 32 which is inserted into the air nozzle 13. The air nozzle 13 is attached to the apparatus by threads 12. For this purpose, the liquid nozzle 35 is provided with a cylindrical portion 23, the outer diameter of which corresponds to the inner diameter of cylindrical member 32 and has a sliding fit therewith. The member 32 abuts against a shoulder 24 of the liquid nozzle 35 and urges it against the supply line 18 when the air nozzle i3 is screwed onto the thread 12. Channels 36 are provided in the member 32 for passage of the atomizing air. Thus, the cylindrical spacer or collar 32 has engagement with the inner surface of the air nozzle at a plurality of preferably uniformly spaced areas around the periphery thereof and has contacting engagement with the entire periphery of the liquid nozzle 13, thereby serving to hold the nozzles in exactly concentric relationship.

The embodiment of FIGS. 5 and 6 can more easily be manufactured than the arrangement of FIGS. 3 and 4. Although there is no self-adjustment, the outer diameter of liquid nozzle 35 and the inner diameter of spacer member 32 can be made with such accuracy that substantial concentricity of the nozzles is obtained.

In the arrangement shown in FIGS. 5 and 6, spacer member 32 is shown as a separate unit, but it should be understood that it may be formed integrally with one of the parts, such as the liquid nozzle 35. Under those circumstances, the outer face of the liquid nozzle would contact directly against the inner face of the air nozzle. In this connection, as previously pointed out, it is sufficient to have contact at a plurality of points or lines lying along at least three envelope or mantel lines, thereby insuring a co-axial relationship. In the arrangement shown in FIGS. 5 and 6, it will thus be `seen that the liquid and air nozzles are held in co-axial relationship, and that the liquid nozzle may be readily replaced and exchanged without the need of special tools or skilled personnel.

In both forms of my apparatus, shown in FIGS. 3 and 4 and FIGS. 5 and 6, respectively, the nozzles are maintained in concentric relationship by spacing or guiding means providing engagement at a plurality of circumferentially spaced portions between the liquid nozzle and the inner surface of the air or gas nozzle. The discharge end of the liquid nozzle is free from obstruction around the outer surface thereof and the air enter-ing through supply line 22 and the air nozzle would be uniformly distributed around the end of the liquid nozzle and there will be a uniform reduction in pressure.

Modifications may be made in the illustrated and described embodiments of my invention without departing from the invention as set forth in the accompanying claims.

I claim:

1. An atomizing nozzle assembly having concentrically arranged liquid and air nozzles adapted for detachable connection to an externally threaded mounting having a front face with liquid and air supply channels comprising a tubular air nozzle having an inner surface which is circular in cross-section for substantially its entire length and formed with a discharge outlet at its forward end and an internally threaded flange -at its opposite end for detachable connection yto the mounting with the interior of the nozzle in communication with the air supply channel in the face thereof, a tubular liquid nozzle shorter in length than the air nozzle and disposed wholly inside the air nozzle with a discharge outlet at its forward end spaced inwardly from the discharge outlet of the air nozzle and with a sealing surface at its opposite end spaced inwardly from the attaching flange of the air nozzle and cooperable to seal against and having abutting engagement only with the face of the mounting in communication with the liquid supply channel when the attaching flange is attached to the mounting and guiding means between the liquid and air nozzles spaced inwardly from the discharge end of the nozzles and having at least three circumferentially spaced relatively elongated longitudinally extending guiding means engaging the inner surface of the air nozzle for substantially their entire length and shaped and arranged to conform with the envelope shane of the inner surface of the air nozzle, said liquid nozzle being free from direct connection with said mounting and having only said abutting engagement with the face thereof so that the liquid nozzle is held in fixed concentric position with respect to said air nozzle solely by said longitudinally extending guiding means.

2. An atomizing nozzle assembly having concentrically arranged liquid and air nozzles adapted for detachable connection to an externally threaded mounting having a face with liquid and air supply channels therein as set forth in claim 1 in which the inner surface of the tubular air nozzle is conical in shape and the circumferentially spaced, relatively elongated, longitudinally extending guiding means are in the form of conical envelope lines having the same apex angle as the inner surface of the air nozzle.

3. An atomizing nozzle assembly having concentrically arranged liquid and air nozzles adapted for detachable connection to an externally threaded mounting having a face with liquid and air supply channels therein as set forth in claim l in which the guiding means consists of a separate member fitted tightly between the air and liquid nozzles.

4. An atomizing nozzle assembly having concentrically arranged liquid and air nozzles adapted for detachable connection to an externally threaded mounting having a face with liquid and air supply channels therein as set forth in claim l in which a sealing annulus is provided between the sealing surface of the liquid nozzle and the front face of the mounting.

References Cited in the tile of this patent UNITED STATES PATENTS 918,754 Lederer Apr. 20, 1909 1,762,552 Gradolph June 10, 1930 2,034,660 Lohse Mar. 17, 1936 2,895,685 Peeps July 2l, 1959 2,965,309 Parrott Dec. 20, 1960