US2530689A - Powder dispenser - Google Patents

Description

1950 E. J. w. EGGER ETAL 2,530,689

POWDER DISPENSER Filed July 30, 1946 INVENTORS EDWARD J. m 5665/? DAV/D E. LYTLE BY M ATTORNEY Patented Nov. 21, 1950 UNITED STATES PATENT OFFICE POWDER DISPENSER Application July 30, 1946, Serial No. 687,114

7 Claims. (01. 302-53) This invention relates to powder dispensing wherein powdered material is entrained by a flowing stream of gas and conducted through an ejector unit to a point of use and more particularly to the use of a powder supporting plate in the powder dispenser above the ejector unit. The invention involves improvements over the powder dispensers disclosed in Patent No. 2,327,337, issued August 24, 1943, in the name of Charles J. Burch and in application Serial No. 592,906, filed May 9, 1945, in the name of Edward Meincke, now Patent No. 2,524,919.

Among the objects of the present invention are the provision of a powder dispenser which will discharge continuously from a storage container a desired quantity of powder in a flowing air stream regardless of the quantity of powder stored in the container; which will prevent packing of the powder around the ejector unit either during operation or during periods of idleness; which will function reliably to supply a desired quantity of powder at the start of a flame cutting operation as well as after the flame cutting operation is well advanced; and which will deliver to a blowpipe a continuous stream of air and uniformly distributed powder entrained therein for making smooth, accurate kerfs in metal bodies.

According to the invention a powder dispenser comprises a powder container having upper and lower ends, which is provided with a gas supply conduit having a vertical portion extending centrally downwardly in the container and terminating in an outlet for gas. Secured to the gas supply conduit near the lower end thereof in position to shield the gas outlet is either a flat disc or a conically shaped plate spaced above a powder ejector unit located in the bottom of the powder container and extending laterally from the gas supply conduit. When the container is charged with fine powder, the weight of a considerable portion of powder is supported by the plate or disc thereby preventing packing of the powder around the ejector unit and around the gas outlet of the gas supply conduit. Furthermore, because of the large diameter of the plate or disc, a space directly beneath the plate or disc is kept free of powder thereby facilitating the flow of gas from the gas supply conduit through a constant depth of powder to the ejector unit even though the level of powder in the container falls as powder is discharged. The shortened distance that the gas must travel also prevents any slight packing which might tend to occur about the ejector unit and also facilitates conveying the powder into the ejector unit.

The novel features of the invention will be apparent from the description of the invention which follows when considered in conjunction with the accompanying drawing, in which:

Fig. 1 is an elevational view, partly broken away and in section, of the preferred form of powder dispenser embodying the invention; and

Fig. 2 is an elevational view, partly broken away and in section, of a part of a modified form of powder dispenser.

Referring to Fig. 1, there is shown one form of powder dispenser comprising a closed vertical cylindrical container C which may be supported in any suitable way, as by a plurality of legs L, two of which are partially shown in the drawing. The dispenser also comprises a removable and replaceable ejector unit D detachably secured to the bottom of the container and providing an outlet for powder. The top of the container C is closed gas tightly by a cover l which rests on the upper edge of the container. Several bolts II are swivelled to posts [2 on the container C for movement into and out of slots l3 formed by horizontal projections l4 extending outwardly from the cover l0. When the bolts II are within the slots l3, the cover is held tightly in place by heavy wing nuts l5 threaded on the bolts and bearing against the top surface of the projections.

The ejector unit D is mounted centrally on a disc shaped plate l6 which is detachably bolted tightly to the underside of the bottom of the container, the upper portion of the ejector unit extending axially into the interior of the containe through a central opening I! in the container bottom. The ejector unit comprises a hollow dome and a bleeder tube l8 shaped like an inverted U having one leg extending downwardly into the dome with the other leg passing through the plate [6 to the outside of the container, and connected to one end of a gas supply conduit I9 which is controlled by a valve 29. Conduit I9 passes through the bottom of the container and extends upwardly to establish communication with a gas supply conduit 20 disposed near the top of the container.

The gas supply conduit 20 comprises a horizontal pressure equalizer portion 2| and a vertical downwardly extending discharge nozzle 22 axially disposed within the container and having an opening in its lower end positioned well below the maximum upper powder level in the concharging a stream of gas through a constant depth of powder even though the upper powder level may be falling. The pressure equalizing portion 2| is provided with a plurality of apertures 23 for supplying gas to the space in the container above the maximum level of the powder.

A horizontal flat disc or plate 24 of smaller diameter than that of the container but of considerable larger diameter than ejector unit D is soldered or otherwise secured to the lower end of the discharge nozzle 22 a fixed distance above the ejector unit D in overhanging relation thereto to support a portion of the weight of the pow der in the container. The plate prevents packing of powder particles around the ejector unit thereby eliminating jamming of the ejector unit; the plate also shields the lower end of conduit 22 so that powder will not be jammed into the outlet of the conduit to stop gas flow; and finally it causes a large hollow space to form below the plate so that the pressure of the gas from conduit 22 will be distributed more evenly within the powder supply. However, the plate 213 is of a size to permit powder above it to flow downwardly over its peripheral edge as the supply of powder below the plate is depleted by discharge from the dispenser.

When the container is fully charged with powder, the upper powder level is below the horizontal pressure equalizing portion 21 of the gas supply conduit 29 while beneath the disc 24 an inverted cone shaped space S is formed into which gas is discharged from the nozzle 22.

Communication between the gas supply conduit 20 and a source of gas for operating the dispenser is established by a second conduit 25 coupled to the supply conduit 29 in a side wall of the container C in such a wa that the gas supply conduit 28 is supported by the side wall. For regulating the gas pressure in the dispenser, an automatic pressure regulating valve 23 is interposed in the conduit 25 and a gas cleaner 21 is also installed in the conduit 25 upstream of the regulator, both the cleaner and the regulator being supported by a bracket 28 welded to the outside of the container C.

In the operation of the powder dispenser shown in Fig. l, the cover is removed and container C is filled with a powder such as a powdered metal to a level just below the pressure equalizing portion 2!, after which the cover It is replaced. With valve 29 adjusted to give the desired rate of gas fiow through the bleeder tube l3, gas is fed to the gas supply conduit 2%). A portion of the gas is discharged through the plurality of apertures 23 into the space above the powder level to equalize the gas pressure at the top and bottom of the container C, and works its way down through the powder to the bottom of the container C.

Another portion of the gas passes into the discharge nozzle 22 and is discharged into the space S below the disc 24 within its periphery and spaced from the ejector unit D. This portion of the gas has a relatively short distance to travel through the powder to the inlet ports 3!] in the side wall of the dome of ejector unit D and therefore is more effective in conveying powder particles into the ports 30 than gas working its way down from the apertures 23. Furthermore, the velocity of the gas flowing toward the ports 3! tends to keep the powder particles around the ejector unit in an active state thereby precluding any packing tendency which may interfere with proper powder flow into the ports. Furthermore, with the lower end of nozzle 22 protected from packing of powder by the disc 24, a more equal distribution of gas pressure over the wide powder area under the disc is possible in addition to maintaining a constant effective pressure head even though the powder level is falling.

A third portion of the gas entering the supply conduit 20 is by-passed through conduit I9 into the bleeder tube I8 from which the gas travels at a substantial velocity axially downwardly and is injected into a discharge conduit 4|. Powder passing through the ports 30 to the interior of the ejector unit D is carried upwardly to the entrance of the discharge conduit 4! both by the gas which works its way down through the mass of powder and by the suction created by the gas fiowing from the bleeder tube It into the discharge conduit M, and then passes downwardly into the delivery pipe P connected to the outside of the dispenser.

In Fig. 2 there is shown a container 0 having an inverted frusto conical bottom wall 35 for facilitating the flow of powder to a suitable ejector unit, e. g., similar to the one shown in Fig. 1. A conduit 32 within the container C cornprises a downwardly extending injector nozzle 33 disposed axially in the container and a horizontal pressure equalizing portion near the top of the container connected to the upper end of the nozzle 33 and provided with a plurality of apertures 35. A hollow cone shaped plate 36 is secured at its apex by suitable means to the nozzle 33 above its discharge end so that the nozzle extends downwardly through the apex of the cone and the discharge end of the nozzle is disposed above the lower edge of the plate 35. A conduit 3'! is coupled to the gas supply conduit 32 within the container by a T coupler 38 which communicates with a second conduit 39 extending through the side wall of the container and leading from a source of gas supply.

Gas is supplied to the ejector unit by conduit 3'! and is regulated from the outside of the container by a valve 4!. Gas is supplied to the container C by conduit 32 through apertures 35 and nozzle 33.

The plate 35 not only supports the weight oi much of the powder in the container but also in conjunction with the gas entering through nozzle 33 and apertures 35, prevents packing of powder particles about the dispensing unit to facilitate powder flow into the latter.

The operation of the powder dispenser of Fig. 2 is substantially identical with that of the dispenser of Fig. 1. In both instances the powder is carried into the ejector unit by the gas working its way down through the mass of powder and by the suction created by the gas flowing through the dispensing unit.

While specific embodiments of the invention have been disclosed to illustrate the principles of the invention it is to be understood that the invention may be otherwise embodied within the scope of the appended claims.

What is claimed is:

1. A powder dispenser comprising a container adapted to hold a supply of powder, conveying means connected to the bottom of said container for conveying said powder to the outside of said container, means for supplying gas to said conveying means, a gas conduit comprising a downwardly extending nozzle axially disposed in said container and having a discharge outlet at its lower end, said conduit having a plurality of apertures therein for discharging gas into said container above the powder level, and a downwardly diverging conical powder-supporting member having its apex portion secured to said nozzle above said discharge outlet, the lower end of said member having a smaller diameter than the interior of said container.

2. A powder dispenser comprising a powder container having upper and lower ends and a side wall, said container being adapted to be filled with powder to a maximum upper level; said container having an outlet for powder in said lower end; means for injecting gas into said outlet; a powder supporting shield in said container wholly spaced above said outlet and located well below said maximum upper powder level, said shield overhanging said outlet and having its periphery spaced from said side wall to permit powder to pass below said shield, said shield providing a space on the underside thereof; and a gas supply conduit having a discharge opening in said container so disposed as to discharge gas therefrom at a position below said shield within the periphery thereof and spaced above said outlet.

3. A powder dispenser in accordance with claim 2, wherein said shield is a flat horizontal plate.

4. A powder dispenser comprising a powder container having upper and lower ends and a side wall, said container being adapted to be filled with powder to a maximum upper level; said container having an outlet for powder in said lower end; means for injecting gas into said outlet; a gas supply conduit extending from the outside to the inside of said container and supported thereby, said gas supply conduit having a discharge opening in said container at a position spaced above said outlet and well below said maximum upper level; and a powder supporting shield in said container centrally supported by said conduit well below said maximum powder level, said shield being wholly spaced above said powder outlet, overhanging said powder outlet, and having its periphery spaced from said side wall to permit powder to pass below said shield, said shield providing a space on the underside thereof which is supplied with gas by said gas supply conduit.

5. A powder dispenser in accordance with claim 4, wherein said shield is a flat horizontal plate secured to said conduit adjacent said discharge opening.

6. A powder dispenser comprising a closed powder container having upper and lower ends and a side wall, said container being adapted to be filled with powder to a maximum upper level;

said container having an outlet for powder in said lower end; means for injecting gas into said outlet; a gas supply conduit extending from the outside to the inside of said container and supported thereby, said conduit including a portion in communication with the space in said container above said maximum upper level and a portion provided with a discharge opening at a position spaced above said outlet and well below said maximum upper level; and a powder supporting shield in said container centrally supported by said conduit above said discharge opening and well below said maximum powder level, said shield being wholly spaced above said powder outlet, overhanging said powder outlet, and having its periphery spaced from said side wall to permit powder to pass below said shield, said shield providing a space on the underside thereof which is supplied with gas by said gas supply conduit.

7. A powder dispenser comprising a powder container having upper and lower ends and a side wall, said container being adapted to be filled with powder to a maximum upper level; a hollow dome at the lower end of said container having a side wall provided with ports for admitting powder to the inside of said dome; a powder discharge conduit having a powder entrance within said dome; means for injecting gas into said discharge conduit through said entrance; a powder supporting shield in said container wholly spaced above said dome and located well below said maximum upper powder level, said shield overhanging said dome and having its periphery spaced from said side wall to permit powder to pass below said shield, said shield providing a space on the underside thereof; and a gas supply conduit having a discharge opening in said container aligned with said dome and so disposed as to discharge gas therefrom into said space at a position below said shield within the periphery thereof and spaced above said dome.

EDUARD J. W. EGGER. DAVID E. LYTLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 681,867 Bardwell Sept. 3, 1901 758,118 Sticker Apr. 26, 1904 1,535,991 Crom Apr. 28, 1925 1,817,240 Cuthbertson Aug. 4, 1931 2,264,108 Anderson et a1. Nov. 25, 1941 2,327,337 Burch et al Aug. 24, 1943

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