US2310620A - Dusting machine - Google Patents

Description

2 Sheets-Sheet l E. R. DYE

DUSTING MACHINE Filed Sept. 26, 1941 Feb. 9, 1943.

3mm Zia/aid)? fife Feb. 9, 1943. E. R. DYE

DUSTING MACHINE Filed Sept. 26, 1941 2 Sheets-Sheet 2 W OOOOOOOA ooooooooo 00000000 0000000 000000 00000 0000 Patented Feb. 9, 1943 nusrnva moms Edward R. Dye, Bozeman, Mont, assignor to Executive Board: of Montana State College- Bozeman, Mont.

' Application September 26, 1941, Serial No. 412,513

2 Claims.

This invention relates to improvements in dusting machines and more particularly to improvements in insecticide dust blowing equipment.

In insecticide dust blowing equipment a callbrated dust feed is necessary to secure economical use of the insecticide. For advantageous results it is highly essential that there be a uniformity of dust feed for any selected calibration. It is also important that the dust feed be positive, that is non-clogging, and that the dust discharge be easy to start even after packing of the insecticide as a result of transportation of the equipment. In dusting equipment the dust is conventionally discharged into an air stream and it will be easily understood that it is also important to secure a uniform distribution of dust in all portions of the air stream. The insecticide used in such equipment is conventionally in the form of a very fine powder and it is not uncommon for the particles to range from one-thousandth to fifteen one-thousandths millimeters in diameter. The diificulties incident to the use of such fine dust in prior dusting equipment have been numerous and to the best of my knowledge the dusting machines heretofore known have not been capable of functioning to accomplish the results heretofore mentioned as desirable.

It is the primary object of my invention to overcome the objections heretofore experienced in dusting equipment and to provide a dusting machine having a calibrated feed which is positive and uniform not only as to the amount of dust discharged at any given calibration but also as to the uniformity of distribution of dust through the air stream. According to my invention I also provide an arrangement wherein the dust feed starts easily regardless of packed conditions of the dust.

An important feature of my invention resides in the provision of an agitator combined with a novel feed valve to eliminate the necessity for relative rotation between the various elements of the feed valve during normal operation of the dusting machine.

Other objects and advantages of my invention will be obvious while others will be specifically.

Figure 3 is a view partly in rear elevation and partly in section;

Figure 4 is a side elevational view of a hollow cylinder which forms a portion of the dust feed valve;

Figure 5 is a view showing a development of a portion of the surface of the hollow cylinder shown in Figure 4 but on a somewhat reduced scale;

Figure 6 is a side elevational view of the a itator and Figure 7 is an end elevational view of the agitator.

The reference numeral 8 designates generally a support for that portion of the dusting machine which embodies my invention. Mounted upon support a is a hopper 9 having sloping bottom walls it as is best shown in Figure 3. The hopper a is provided with a cover H. The front wall 82 of the hopper is in the form of a panel which extends from the base of the support 8 to the top of the hopper 9.

The extreme bottom of the hopper is arcuate in transverse section as is best seen by reference to the numeral E3 in Figure 3. In the bottom of the arcuate trough i3 are a number of aligned openings designated by the reference numeral it in Figures 2 and 3. Ten of the openings it are shown although any desired number may be employed.

Below and adjacent the arcuate trough I 3 is a hollow cylindrical pipe designated by the reference numeral l5 and which for purposes of convenience is hereinafter referred to as a tunnel. By reference to Figures 2 and 3 it will be noted that the openings M extend through the wall of the tunnel I5 to thus form a communication between the interior of the hopper 9 and the interior of the tunnel it. The tunnel to converges slightly at It and communicates with a discharge conduit ii.

Disposed within the tunnel i5 is a hollow cylinder it provided with an adjusting handle member i9. As shown inFigure 2 the rightward end of the hollow cylinder i8 abuts against the converging'portion I 6 of the tunnel i5 and is held in such abutting relationship by means of a bar 2t bearing against the leftward end of the hollow cylinder.

As is best shown in Figures 4 and 5, the wall of the hollow cylinder I 8 is provided with a plurality oi series of apertures 2! which are preferably of the same size or larger than the openings Id in the arcuate trough it of the hopper. It will be seen that these apertures 2! are arranged in a 2 series of rows extending longitudinally of the hollow cylinder I8. In one row there is a single aperture, in the next row there are two apertures, in the next row there are three apertures. and this continues until in the last row there are ten apertures to correspond with the ten openings H in the arcuate trough It. It will therefore be readily apparent that the hollow cylinder,

It may be rotated about its own longitudinal axis by means of the handle member N to align any number of apertures 2|, betweenthe limits of zero and ten, with openings l4. That is to say it is possible to selectively adjust the hollow cylinder l8 in such manner that the interior of the hopper 9 communicates with the interior of the hollow cylinder l8 through one or ten or any intermediate number of passagewayaor in such manner as to close all of the openings l4.

Attached to the front of the panel l2 there is provided an indicator bar 22 which serves to retain the handle is in the selected position by means of notches 23 which cooperate with a detent 24 on the handle l9.

Within the hopper 9 and so positioned and dimensioned as to fit within the arcuate trough I3 is an agitator 25. This agitator comprises a polished cylinder 26 provided with polished metal fins 21 which are designed to agitate and break up the dust in the hopper by destroying all cakes or lumps and to sweep the dust uniformly past the feed openings M. It will be noted that the adjacent fins are in the form of oppositely arranged helixes along the surface of the cylinder 26. The agitator '25 is mounted in dust proof bearing 28 and is adapted to be driven by suitable means such as a motor 29 through a belt 30.

Suitable means such as a blower Ila is provided for causing a stream of air to pass rapidly through the hollow cylinder l8 and the conduit I'I. Such means may be any conventional form of blower or other suitable arrangement. The conduit l'l should be attached to the intake of the blower Ila which should ,be driven at appropriate speed to maintain a constant vacuum head in the hollow cylinder l8.

Although the operation of the apparatus should now be clear it will be described briefly. The handle member I9 is positioned to cause the proper number of apertures 2| to align with openings I 4 to give the desired rate of discharge of dust into the air stream. The motor 29 should then be started which will cause the agitator 25 to rotate. The blower lla should also be placed in operation. Rotation of the agitator will assure a continuously uniform sweeping of dust over each opening l4 and consequently will discharge dust into the interior of the hollow cylinder l8 through each aperture 2| which is in alignment with an opening M. This dust will be picked up by the air stream passing through the hollow cylinder l8 and the conduit l1.

In addition to the general principle of operation described above I have found that there are severalimportant considerations to be borne in mind in the design of the apparatus embodied in my invention. The diameter of the agitator 25 should be greater than the span of possible arching of the dust to be used in the hopper. It is important that the agitator 25 be driven or actuated at low speed in order that the centrifugal force imparted to the dust will be less than gravity. The openings [4 and the apertures 2| should be of a diameter larger than the critical clogging diameter for any particular dust which is likely to be used in the machine.

By this invention I have provided a calibrated I feed for a dusting machine which is positive and highly uniform for any particular calibration. The uniformity of feed appears to be due in large measure tov the peculiar design and shape of the agitator which uniformly conditions the dust for each opening H, moving equal amounts of dust under equal pressure over each opening, to the fact that the dust feeding passageways remain fully open instead of being periodically closed or partially closed during normal operation, which closing would cause an undesirable throttling eflect.

A feature which I consider of great importance is the practical elimination of friction between closely fitting moving parts. The only movement necessary between the tunnel l5 and the hollow cylinder It occurs during calibration or adjustment of the feed, since in normal use there is no relative rotation between these two elements. The openings communicating from the interior of the hopper to the air stream are not closed and there is no periodic cup dosing as is the case when the coacting parts of alfeed valve rotate relative to each other. Not only does my arrangement eliminate wear of the feed valve but it prevents a packing of dust between relatively moving surfaces.

It is to be understood that the form of the invention herein shown and described is the preferred form but that various changes in detail may be resorted to without departing from the scope of the invention as defined by the following claims.

Having thus described my invention, I claim:

1. An adjustable discharge dusting machine comprising a dust hopper having an arcuate trough at the bottom thereof, a tunnel below said trough, a plurality of openings in the wall of said tunnel communicating with the interior of said trough, a normally stationary member within said tunnel and fitting closely to the inner wall thereof, means for selectively adjusting said member to'close one or more of said openings in said tunnel wall to thus selectively vary the number of openings communicating between said tunnel and said trough interior, a rotor assembly extending longitudinally of said trough, said rotor assembly comprising a cylinder of a radius slightly less than the radius of said trough to prevent uncontrolled flow of dust from said hopper to the bottom of said trough and narrow fins extending helically about the circumference of said cylinder, means for rotating said rotor assembly to convey dust from said hopper to the bottom of said trough and to sweep said dust across said openings, and means for causing a flow of air at reduced pressure longitudinally through said tunnel.

2. An amustable discharge dusting machine comprising a dust hopper having an arcuate trough at the bottom thereof, a cylindrical tunnel below said trough, a plurality of openings in the wall of said tunnel communicating with the interior of said trough, a hollow cylinder extending through said tunnel and fitting closely with the inner wall thereof, a plurality of series of apertures in the wall of said hollow cylinder, each series being composed of a different number of apertures, means for selectively adjusting said hollow cylinder to cause the apertures of any one of said series to align with openings in said tunnel wall and to thus communicate with the interior of said trough, a rotor assembly extending longitudinally of said trough, said rotor assembly comprising a cylinder of radius slightly less than the radius of said arcuate trough and a plurality of narrow helical fins on the circumference of said rotor cylinder with adjacent fins being oppositely arranged helixes, means for ro-

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