US 3399466 A
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P 3,1968 N. HARTLEY 3,399,466
SAND HOPPER Filed June 21, 1967 2 Sheets-Sheet 1 mvewroia N54 .50 A/ HRETLE 14%, AM, H0w Chum Sept. 3, 1968 N. HARTLEY 3,399,466
SAND HOPPER Filed June 21, 1967 2 Sheets-Sheet Z /5 F 3 ,,...w Jim? z A4 ,,II-'"" "#1,, E 3 O NEL$ON Hnerzsv INVENTO 2 ATTOR NEWS United States Patent 3,399,466 SAND HOPPER Nelson Hartley, Towson, Md., assignor to Hartley Controls Corporation, Neenah, Wis., a corporation of Wisconsin Filed June 21, 1967, Ser. No. 647,794 7 Claims. (Cl. 34-167) ABSTRACT OF THE DISCLOSURE Disclosed herein is a sand hopper having an inverted V-type flow baflle in the bottom of the hopper to define two diverging discharge slots located above a continuously movable conveyor with ventilating means to remove heat from the space beneath the baffle.
Background of the invention This invention relates to hoppers for granular material such as those which are used as reservoirs for molding sand and more specifically to an improvement in the discharging of sand from the hopper.
Sand hoppers of the present type are used to collect sand as its returns for reuse from the shake out apparatus in a foundry. The sand is typically discharged from the hopper onto a moving conveyor which carries it back to the foundry for reuse. Some of this sand, as it is discharged from the shake out apparatus, is quite hot, while other portions of the sand will be cool with varying degrees of moisture present in the sand in the hopper. If the sand remains stationary in the hopper for any period of time it will have a tendency to become incrusted in the discharge openings ofthe hopper due partly to the influence of the high temperature of the sand and moisture present in the sand. It has been found in sand hoppers presently being used, that the discharge openings have poor flow patterns resulting in a build up of sand which then becomes incrusted in the opening and eventually clogging the opening. When this happens the hopper and its belt must be taken out of service until the incrusted sand is removed from the hopper. This may take four or five hours.
Summary of the invention In the sand hopper of the present invention the discharge opening in the mouth of the hopper is designed to provide a continuous flow of sand along the length of the hopper as it flows onto the conveyor. Moreover, build up of heat at the hopper mouth is prevented. This is accomplished by positioning a baflie means in the mouth of the sand hopper in spaced relation to a conveyor belt which moves under the hopper mouth. The hopper mouth is wider at the downstream end of the belt than at the upstream end producing a diverging type opening along the path of the conveyor. The outer edges of the baflle are located in a parallel, spaced relation to the side walls of the hopper forming narrow discharge slots along each side of the hopper. With this arrangement unloaded portions of the conveyor belt will pass beneath a greater area of the hopper mouth assuring removal of sand from the entire area beneath tthe discharge slots. The space under the bafile is exposed to the atmosphere to permit air to circulate under the baflie to reduce the temperature of the sand as it passes through the openings and preclude heat build up in the hopper.
Other advantages and objects of the present invention will become apparent from the following detailed description when read in conjunction with the enclosed drawings, in which:
FIG. 1 is a perspective view of the sand hopper showing the baflle in phantom.
Patented Sept. 3, 1968 FIG. 2 is a cross-sectional view of the hopper} FIG. 3 is a sectional view taken on line 3-3 of FIG. 1.
FIG. 4 is a sectional view taken on line 44 of FIG. 3.
FIG. 5 is a sectional view taken on line 5-5 of FIG. 2.
Referring more particularly to FIG. 1 of the drawings, hopper 10 for granular material such as sand is shown positioned over a belt-type conveyor 12. The side walls 14 of the hopper flare upward and outward from the conveyor with the rearwall 16 and frontwall 18 positioned in aparallel relation to each other. The hopper is suspended over the conveyor in a conventional manner and requires no further explanation. A typical foundary hopper may contain as much as two hundred tons of sand.
The space between the lower edges of the side walls and the conveyor belt is closed by means of flexible belt seals 20 clamped on support brackets 26 which are welded to the lower edges of the side walls. A flat plate 21 is positioned on the outside of the seal and nuts 22 and bolts 24 are used to draw the plate tightly against the pad. Referring to FIG. 2 it will be noted that the seals are positioned to slide on the surface of the conveyor to prevent any sand from flowing laterally out of the hopper mouth and onto the conveyor belt.
An adjustable leveling and discharge flow control gate 28 is provided at the downstream end of the hopper 10. In some commercial installations gate 28 is controlled by electric or fluid motors. Solely for purposes of exemplification, gate 28 is shown herein as slidably mounted on angle iron 30 secured to the top of support brackets 26. The gate controls the thickness of the layer of sand 32 on the conveyor belt 34. In the illustrated embodiment the gate is adjusted by loosening bolt 36 and ra sing or lowering the gate by flange 40*. A flexible belt seal 45 is also secured to the back wall of the hopper by bolts 47.
A baflie means 50 preferably of an inverted V-type is positioned in the lower portion of the hopper with its ends secured to the front and rear walls. The outer edges 52 of the side walls 54 of the baffle are located in a parallel, spaced relation to the side walls of the hopper to form long narrow discharge slots 56 (FIG. 3) along each side of the hopper. In a typical embodiment slots 56 are about 14 inches wide. The sand which flows past the discharge slots will flow laterally to bridge and fill the space 58 in the hopper beneath the baflle. As soon as this space fills with sand the flow through the slots will stop and only the weight of the sand in this space will bear on the belt. As sand is removed from this space by the belt it will be replaced by sand flowing through the discharge slots. The slope of the side walls of the baffle should be selected to assure that sand will slide down the side wall.
The continuous flow of sand through the full length of both discharge slots is believed to be due in part to the downward converging relation of the side walls of the hopper as well as the slots formed by the baflies. Continuous flow is also attributed to the longitudinal taper of the mouth of the hopper. Referring to FIGS. 3 and 5, it should be noted that the front wall 18 is wider than the rear wall 16. At the bottom of the hopper just above belt 34 the ratio of the width of the downstream end of the hopper to the width of the upstream end of the hopper is desirably 4:1. This means that unloaded portions of the belt will be moving in the direction of arrow 61 under the full length of each of the side walls 14. For example, strips or zones 0, h of the belt will pass under the front section of the side wall. Strips b, g will pass under the center section while strips 0, 1 will pass under the rear sections. Strips d, e pass through the full length of the hopper. This constant movement of unloaded strips or zones of the belt along the full length of the walls moves the sand away from the side walls 14 to continuously open the space near the side walls that is continuously filled by sand flowing down the side wall through the slots 56.
Visual observation of the sand as it passes the baffle edges 52 reveals a continuous movement along the entire length of the bafile with no dead or stagnant spots. The rate of sand flow is adjusted by raising or lowering the gate 28.
The sand is cooled by means of natural or forced circulation of air through the space beneath the bafile 54. Aperture 62 in front wall 18 and aperture 64 in the rear wall 16 are aligned with the cavity 66 immediately beneath the bafile. A fan 60 may optionally be mounted to force air through this space. This circulation of air reduces the temperature of the sand and prevents build up and entrapment of heat, thus to remove one of the chief causes of encrustation of the sand on the side walls and on the bafile.
Although only one embodiment of the present invention has been shown and described it should be apparent that various changes and modifications can be made herein without departing from the scope of the appended claims.
What is claimed is:
1. The combination of a hopper for granular material having end walls and downwardly converging side walls and a conveyor positioned to move under the hopper, of means for controlling the flow of sand from the hopper comprising:
baflle means positioned within said hopper in upwardly spaced relation to said conveyor,
said bafile having edges generally extending along and spaced from the side walls of the hopper to form discharge slots along both sides of the hopper, the end wall of the hopper upstream of the conveyor being narrower than the end wall of the hopper downstream of the conveyor,
whereby sand removed from the hopper by the conveyor will be replaced by sand flowing onto the conveyor along the entire length of both discharge slots.
2. The combination according to claim 1 including means to circulate air through the space beneath the baflle.
3. The combination according to claim 1 wherein the battle means comprises an inverted V-type bafile.
4. A hopper arrangement for feeding a layer of granulat material onto a continuously moving belt comprismg:
a hopper having upwardly and outwardly flared side walls,
conveyor means positioned to move beneath the hopsaid hopper side walls diverging in the direction of movement of said conveyor,
baffle means positioned in the hopper in a spaced relation to the conveyor means,
said batfie means being located in a spaced relation to said side walls to define two diverging discharge slots, and
means for circulating air through the space beneath the baflle means to cool the granular material as it flows over the baffle means.
5. A hopper arrangement according to claim 4 wherein said baflle means comprises an inverted V-shaped baflle having downwardly and outwardly directed side walls.
6. The hopper arrangement of claim 4 in which the hopper has an adjustable gate at its downstream end to control the discharge rate from the hopper.
7. A sand hopper for molding sand comprising:
a hopper having upwardly diverging side walls,
said hopper side walls also diverging from upstream to downstream and forming a tapered discharge opencontinuously movable conveyor means positioned below said hopper,
a bafile positioned across said opening and having edges spaced from the walls of said hopper,
a leveling gate on the front of the hopper,
adjusting means to vary the space between the gate and the conveyor, and
cooling means to remove heat from the vicinity of the bafile.
References Cited UNITED STATES PATENTS 695,004 3/1902 Speer 34-l70 1,752,549 4/1930 Beardsley et al. 2,758,700 8/1956 Plumb 19857 FREDERICK L. MATTESON, 111., Primary Examiner. A. D. HERRMANN, Assistant Examiner.