US3717752A

US3717752A - Particle spraying device

Info

Publication number: US3717752A
Application number: US00156232A
Authority: US
Inventors: W Warning
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-06-24
Filing date: 1971-06-24
Publication date: 1973-02-20
Anticipated expiration: 1990-02-20

Abstract

A multiple screw auger mounted at the bottom of a hopper carries the particles to a spray device which extracts the particles from the outlet end of the auger and directs them in a predetermined pattern toward a workpiece.

Description

United States Patent [1 1 Warning 51 Feb. 20, 1973 [54] PARTICLE SPRAYING DEVICE [76] Inventor: Walter B. Warning, 2424 N. Nordica Ave., Chicago, 111. 60635 [22] Filed: June 24, 1971 [21] Appl. No.: 156,232

[52] US. Cl. ..239/654, 239/675, 239/424.5 [51] Int. Cl ..A01c 3/06 [58] Field of Search ..239/694, 669, 675, 418, 423,

[56] References Cited UNITED STATES PATENTS 1,970,021 8/1934 Peters et al. ..302/50 X 3,152,065 10/1964 Sharp 61 al.".

1,128,043 2/1915 Quigley .222/413 UX 2,127,693 8/1938 McCanless et a1. ...302/50 2,315,079 3/1943 Reeves ..302/50 Primary Examiner-Allen N. Knowles Attorney-Raymond E. Fidler et al.

[ 5 7 ABSTRACT A multiple screw auger mounted at the bottom of a hopper carries the particles to a spray device which extracts the particles from the outlet end of the auger and directs them in a predetermined pattern toward a workpiece.

8 Claims, 8 Drawing Figures PATENTE FEBQD 1m 7 l 7, 7 52 YSHEET 10F 2 FIG. 3

FIG. 2

INVENTOR WALTER B. WA RN/NG ATTORNEYS PATENTEDFEBZOIQYS SHEET 2 [IF 2 FIG. 6

INVENTOR WALTER B. WARN/N6 BY 7 ATTORNEYS PARTICLE SPRAYING DEVICE The present invention generally relates to the art of spraying particulate matter onto a workpiece, and it relates more particularly to a new and improved method and apparatus for providing a uniform dispersement of particles in any one of a plurality of preselected patterns.

In the past, various methods and techniques have been employed for applying a coating of particulate matter to the surface of a workpiece. Gravity, air jets and electric fields have all been used for this purpose, but except when highly complex and expensive equipment has been employed, uniformity of particle distribution has'not been achieved. Variations in size, surface configuration and moisture content of the particles has resulted in irregular spray patterns and in some cases in complete interruption of the particle spray.

Another disadvantage of the prior art devices is the limited application of any particular piece of equipment without extensive modification. Many of the earlier devices had to be custom designed and built for a particular use. It would be desirable, however, to provide a particle spray device which could be used with different types and sizes of particulate matter and which could be readily adjusted to provide any one of a plurality of different spray patterns.

Accordingly, a principal object of the present invention is to provide a new and improved method and apparatus for spraying particulate matter.

Another object of this invention is to provide a new and improved device for providing a uniform spray of solid particles.

A further object of this invention is to provide a particle spray device having readily changeable means for varying the spray pattern produced thereby.

A still further object of this invention is to provide apparatus for applying a coating of food particles to the surface of an article.

Briefly, the above and further objects may be realized in accordance with the present invention by providing an auger for carrying particles from a hopper or the like to a spray means located at the outlet end of the auger for extracting the particles from the auger and directing them in a predetermined pattern toward the workpiece. The spray means may be a plurality'of spray orifices mounted in proximity to the outlet end of the auger to create a small vacuum just forward of the auger which extracts the particles therefrom. Preferably, the spray orifices are provided in a removable plate mounted over a manifold plate to permit the facile exchange of plates to alter the spray pattern.

In accordance with another aspect of this invention, the spray device is mounted adjacent to a turntable disposed along a conveyor belt. Articles of food, such as cakes, are fed to the turntable which is rotated during operation of the spray device to apply a coating of food particles such as crumbs to the sides of the cakes.

Further objects and advantages and a better understanding of the invention may be had from the following detailed description taken in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a system embodying the present invention for applying a coating of food particles to the sides of the cakes;

FIG. 2 is a side elevation, partly in cross section of the coating station in the system of FIG. 1;

FIG. 3 is an enlarged, sectional view of the spray mechanism employed in the device of FIG. 2;

FIG. 4 is a front view of the spray mechanism of FIG.

FIG. 5 is an exploded, perspective view of a spray assembly embodying the present invention;

FIG. 6 is a cross-sectional view of another embodiment of the present invention;

FIG. 7 is a front end perspective view of another spray device embodying the present invention; and

FIG. 8 is a cross-sectional view of still another embodiment of this invention.

The present invention is primarily described herein in connection with the application of a coating of edible particles. Inasmuch as such particles are moisture absorbent and generally vary in size, shape and density, it is particularly difficult to apply a relatively uniform coating thereof to another article. Moreover, for reasons of economics, a spray device for the application of food particles should be readily adaptable for use with particles of differing size, density, shape and cohesiveness, and in addition, the spray pattern and concentration of the particles therein should be adjustable. It will be apparent, therefore, that the method and apparatus hereinafter described may be used with most other types of solid particulate matter such, for example, as dry paint particles, textile fibers and reflective flake material.

Referring now to the drawings and particularly to FIG. 1 thereof, a conveyor belt 10 carries a plurality of cakes 11 in seriatim to a spray station 12 wherein a coating of food particles such, for example, as crumbs, nut fragments, granulated sugar or the like, is applied to the side surface of the cakes 11 and a conveyor belt 13 carries the coated cakes to another station. As shown, the individual cakes 11 are disposed on circular trays 14 for convenience in handling. The coating station 12 includes a rotatably mounted turntable 16 which is driven through a chain and sprocket assembly 17 by an electric motor 18. A particle sprayer 20 mounted adjacent to the turntable 16 includes a hopper 21 containing the particulate matter and a spraying head 22 for directing a uniform, preselected pattern of particles toward the vertical side of the cake disposed on the turntable 16.

The system shown in FIG. 1 is of the semi-automatic type utilizing an operator located at the coating station who transfers the cakes from the conveyor belt 10 to the turntable platform 16 and manually initiates operation of the coating mechanism to energize the motor 18 and cause the device 20 to produce the spray of particles. Preferably, although not necessarily, the period of operation of the spray device 20 is automatic and is preset to provide the desired thickness of coating on the cakes. After the coating has thus been sprayed onto the cake located on the turntable 16, the operator transfers that cake to the conveyor belt 13 and transfers the next uncoated cake from the conveyor belt 10 onto the platform 16. It will be apparent to those skilled in the art as the present description proceeds that the spray device 20 may be located and the spray pattern preselected so as to coat not only the sides but also the top of the cake on the platform 16. Similarly and if desired, another spray device 20 may be provided further down the line for spraying a different particulate substance onto the cakes 1 1.

Referring to FIG. 2, it may be seen that a multiple screw auger 25 is rotatably mountedin a rigid tube 26 disposed in the bottom of the hopper 21 which, as best shown in FIG. 1, has sloping bottom side walls 24. The tube 26 is, open along the top so that the particulate matter contained in the hopper 25 is fed by gravity into the spaces between the flutes of the auger. The rear end of the auger is provided with a shaft 27 on which is mounted a sprocket 28 which is connected through a chain 29 to a drive sprocket 30 mounted on the shaft of an electric motor 31. A suitable sealing gland is provided between the rear wall of the hopper 21 and the auger shaft 27 to prevent leakage from the hopper. The forward end of the tube 26, as best shown in FIG. 3, extends through an opening 34 in the front wall 35 of the hopper 21 and provides the forward bearing for the auger 25. The auger, however, extends forwardly beyond the front edge of the tube 26.

An annular manifold plate 36 is secured as by bolts to the wall 36 over the forward end of the tube 26 and is provided with an annular groove 37 in the forward face thereof. An air tube 38 connected to a suitable source of compressed air is connected through a fitting 39 to the back face of the plate 36 below the hopper and is connected by a drilled passageway 40 in the plate 36 to the groove 37. An orifice plate 41 is removably attached as by means of bolts 42 over the forward face of the plate 36 and is provided with a central opening 44 into which the outlet end of the auger extends. A plurality of small diameter orifices 45 are drilled through the plate 41 so as to communicate with the groove 37. The number, direction and position of the orifices 45 determine the spray pattern which is produced when the motor 31 is energized and compressed air is supplied to the spray assembly 22. For ap plying a coating to the sides of a cake as illustrated in the system of FIG.'1, a conical pattern is preferred and, therefore, the orifices 45 are symetrically arranged in a circle surrounding the opening 44 as shown in FIG. 4.

In order to assure that the particles are uniformly dispersed throughout the spray pattern, the auger 25' should be of he multiple screw type having three or four flutes. Moreover, the spray assembly 22 should be as close as possible to the hopper so as to minimize the effect of settling of the particles in the auger from the time they leave the hopper to the time they are picked up by the air jets from the orifice 45 a nd sprayed onto the workpiece. An added advantage of mounting the spray mechanism at the hopper and utilizing the particle spray means to extract the particles from the outlet end of the hopper is that compacting of the particles in the auger and clumping and clogging are eliminated. Moreover, the auger provides a positive feed for the particles so that for a given speed of rotation of the auger 25 a given amount of the particulate matter is sprayed onto the workpiece irrespective of variations in the size, shape and moisture content of the particles.

Although, the particular control circuit utilized with the spray device of the present invention may utilize standard control devices, where the device 20 is operated intermittently as, for example, in the system of FIG. 1, the valve which controls the supply of air to the manifold plate 36 should be opened before the motor 31 is energized to drive the auger thereby to avoid spraying an excessively heavy coating onto the workpiece when the coating device is initially ener gized.

As explained in connection with FIG. 3, the orifice plate 41 is quickly and easily removed from the manifold plate 36 whereby different orifice plates 41 for providing different spray patterns may be easily interchanged. The spray assembly 22 as shown in FIG. 5, includes an adapter plate 41a wherein the orifices are positioned so as to produce a flat spray pattern. As there shown, the orifices45 are located only at the horizontal sides of the center opening 44 thereby to provide a spray pattern which is generally rectangular in cross-sectional shape having a horizontal dimension substantially exceeding the vertical dimension. It will be apparent that other patterns may be provided by proper location of the orifices. Also, the diameter of the orifices may be varied from one plate 41 to another so as to control the density of the spray pattern produced without altering the air pressure supplied to the manifold plate 36. Depending upon the size of the particles and the distance between the spray device and the workpiece, the air pressure to the manifold may vary between about 3 psi. for a fine dust-like material to about p.s.i. for heavier materials.

Referring now to FIG. 6, there is shown another embodiment of the present invention comprising a multiple screw auger 50 mounted in the bottom of a hopper 51 within a tube 52. The central portion of the upper side of the tube 52 is cut away so that the particulate matter within the hopper 51 may fall by gravity into the spaces between the flutes of the auger 50. The auger 50 is journaled at its ends in the tube 52 and is provided with an axial bore 53 which is counterbored and tapped at the forward end to receive an orifice fitting 54 having a slightly flared out orifice. The rear end of the bore 53 is coupled through a suitable swivel coupling 55 to a compressed air line 56. A drive sprocket 57 is secured to the rearwardly extending shaft 58 on the auger 50 for rotating the auger to feed particles at a controlled rate from the hopper to the forward or outlet end as shown at the right in FIG. 6. In this embodiment of the invention, as the auger 50 is rotated to feed the particles to the right-hand end thereof, the air jet eminating from the bore 53 creates a vacuum or low pressure area at the outlet end of the auger to extract the particles therefrom and to direct them in a pattern which is generally circular in cross-sectional shape. It will be apparent that the shape of the orifice in the fitting 54 is determinative of the size of the pattern produced at any given distance from the outlet end of the auger. This embodiment of the invention provides a spray pattern which is necessarily circular in cross-sectional shape but the diameter of the pattern at any given distance from the orifice may be adjusted by varying the pressure to the line 56 or by interchanging spray nozzle pieces 54 having different degrees of flare and different orifice diameters.

In order to provide a non-circular pattern using the auger and spray orifice as shown in FIG. 6, a non-circular pattern control tube may be mounted on the hopper over the outlet end of the auger. In FIG. 7 such a tube 60 is shown in use with a plurality of augers 50 mounted side by sideand each including a control air spray orifice 54. The use of multiple augers enables a greater uniformity of particles in the spray pattern than is achieved using a single auger.

The pattern control tube 60 provides a horizontally elongated generally rectangular pattern. It will be apparent that pattern control tubes of other shapes may be used to replace the tube 60.

Referring to FIG. 8, there is shown another embodiment of the invention wherein the need for a source of compressed air is obviated and in its place is provided a rotating flared-out member 63. The flared out member 63 has a hub portion 64 having connected thereto a drive sprocket 65 which is driven through a chain 66 by a sprocket 67 connected through a step-up gear train 68 to an electric motor 69 which also drives the associated auger. As in the previously described embodiments, the spray producing means of FIG. 8 is located directly at the outlet end of the auger in close proximity to the hopper, and being operated at a high angular velocity of the order 500 to 5,000 rpm. creates a low pressure area at the outlet end of the auger thereby to extract the particles therefrom and direct them in a desired pattern onto the workpiece. As in the embodiment of FIG. 6, the pattern produced by the device of FIG. 8 is necessarily circular in cross section but the diameter of such pattern may be adjusted by interchanging the member 60 with members 63 having different shapes and angies of divergence.

Depending upon the nature of the particulate material being sprayed and the electrical characteristics of the workpiece, the spray means may be of the electrostatic type which produces an electric field for directing the particles toward the workpiece. In accordance with the present invention, such a spray means should be located in close proximity to the outlet end of the auger which, in turn, should be located in proximity to the hopper thereby to avoid the several problems heretofore mentioned.

While the present invention has been described in connection with particular embodiments thereof, it will be understood that those skilled in the art may make many changes and modifications without departing from the true spirit and scope thereof. Accordingly, the appended claims are intended to cover all such changes and modifications as fall within the true spirit and scope of the present invention.

What is claimed is:

1. Apparatus for spraying particulate matter in a predetermined pattern onto a workpiece, comprising a hopper having from and rear walls,

an auger rotatably mounted in the bottom of said hopper with the outlet end of said auger proximately disposed with an aligned opening in said front wall, spray means mounted at said front wall for directing a stream of gas across the outlet end of said auger toward said workpiece to extract particles from said auger and carry them in a predetermined pattern onto said workpiece. 2. Apparatus according to claim 1 wherein said last named means comprises a plurality of orifices disposed in proximity to said outlet end of said auger, and means supplying gas under pressure to said orifices. 3. Apparatus according to claim 1 wherein said last named means comprises a first annular plate having an opening aligned with said auger,

said plate having a manifold groove therein, a second annular plate mountedover said first plate and having a plurality of holes extending therethrough and opening at one end onto said groove, and means for supplying gas under pressure to said groove, whereby the gas emitted from said holes sprays said particulate matter toward said workpiece. 4. Apparatus according to claim 1 wherein said auger has a plurality of flutes.

5. Apparatus according to claim 1 comprising a plurality of said augers mounted in side by side relationship at the bottom of said hopper. 6. Apparatus according to claim 5 comprising a flared out member surrounding the outlet end of said augers for controlling the spray pattern produced thereby. 7. Apparatus according to claim 1 wherein said last named means comprises a divergent tubular member rotatably mounted over and in alignment with said outlet end of said auger, and means for rotating said tubular member. 8. Apparatus according to claim 7 wherein said tubular member is provided with a plurality of helical flutes disposed on the inner wall thereof.

Claims

1. Apparatus for spraying particulate matter in a predetermined pattern onto a workpiece, comprising a hopper having front and rear walls, an auger rotatably mounted in the bottom of said hopper with the outlet end of said auger proximately disposed with an aligned opening in said front wall, spray means mounted at said front wall for directing a stream of gas across the outlet end of said auger toward said workpiece to extract particles from said auger and carry them in a predetermined pattern onto said workpiece.

2. Apparatus according to claim 1 wherein said last named means comprises a plurality of orifices disposed in proximity to said outlet end of said auger, and means supplying gas under pressure to said orifices.

3. Apparatus according to claim 1 wherein said last named means comprises a first annular plate having an opening aligned with said auger, said plate having a manifold groove therein, a second annular plate mounted over said first plate and having a plurality of holes extending therethrough and opening at one end onto said groove, and means for supplying gas under pressure to said groove, whereby the gas emitted from said holes sprays said particulate matter toward said workpiece.

4. Apparatus according to claim 1 wherein said auger has a plurality of flutes.

5. Apparatus according to claim 1 comprising a plurality of said augers mounted in side by side relationship at the bottom of said hopper.

6. Apparatus according to claim 5 comprising a flared out member surrounding the outlet end of said augers for controlling the spray pattern produced thereby.

7. Apparatus according to claim 1 wherein said last named means comprises a divergent tubular member rotatably mounted over and in alignment with said outlet end of said auger, and means for rotating said tubular member.