US 3237753 A
Description (OCR text may contain errors)
March 1, 1966 K. M. ALLEN ETAL ELEVATOR FOR FRAGILE, DISCRETE MATERIAL Original Filed Sept. 24, 1962 l/Vl/E/VTORS.
KENNETH M. ALLEN CHESTER H. HARPER BUCKHORN, CHEATHAM 8 BLORE ATTORNEYS United States Patent 3,237,753 ELEVATGR FGR FRAGILE, DISCRETE MATERIAL Kenneth M. Allen and Chester H. Harper, Newherg, Greg, assignors to Allen-Harper, lnc., Newherg, Greg, a corporation of Oregon Continuation of application Ser. No. 225,728, Sept. 24, 1962. This application Feb. 8, 1965, Ser. N 0. 438,146 4 Claims. (Cl. 198129) This is a continuation of our copending application Serial No. 225,728, filed September 24, 1962.
Our present invention comprises an elevator for fragile, discrete materials of flake type such as potato chips, crackers, and the like. The invention is of particular utility in the manufacture of potato chips in which it may be desirable to elevate the potato chips from a floor-level fryer to an overhead conveyor for distributing the chips into a battery of floor-level packaging machines. A bucket or bracket type elevating conveyor is very wasteful of such articles since the buckets or brackets crush many of the chips. As a result elevators of the flat belt or screen type have been employed in which the chips into a battery of floor-level packaging machines. by gravity. Such a conveyor must be extremely'long since the maximum angle of inclination is around twenty degrees, resulting in loss of valuable space and in some cases the necessity for turntables to bring the potato chips back overhead in the available plant space.
The present invention comprises means for elevating such articles by means of a screen type belt conveyor to which the articles are held by suction and which may travel at a steep inclination closely approaching ninety degrees to the horizontal.
An object of the present invention is to provide a conveyor of the foregoing type in which means are provided to regulate the suction force holding the material to the screen so as to minimize breakage, adapt the machine to articles of diflerent types, and control the quantity of material elevated thereby per increment of time so as to regulate the capacity of the elevator to the capacity of succeeding machines to which the material is to be fed.
The objects and advantages of the present invention will be more readily apparent from inspection of the following specification taken in connection with the accompanying drawings, wherein like numerals refer to like parts throughout, and in which the invention is described and illustrated.
In the drawings,
FIG. 1 is a view in perspective, with parts broken away, illustrating a preferred form of the present invention in association with material supplying and material removing conveying means; and
FIG. 2 is a partial side view of a modified form of conveyor supporting roll.
Referring to FIG. 1, the elevator of the present invention is illustrated in association with a material supplying conveyor 12 for feeding materials to the elevator and a second material conveying means 14 for removing materials from the elevator.
The elevator 10 comprises a suction box 16 having an open, upright side 18 and an open, horizontal top 20, the remainder of the box comprising vertical sides 22, 24 and 26 with which may be associated a bottom wall 28, which in practice may be provided by the floor of the space upon which the elevator rests. An endless screen 30 is mounted on the box in such manner that a nearly vertical flight 32 thereof spans the open side 18 and a succeeding horizontal flight 34 thereof spans the open top 20. The flights 32 and 34 together constitute the feeding flight of the screen and the return flight of the screen is constituted by a flight 36 parallel to the flight 34 and a flight 38 parallel to the flight 32. The screen is preferably attached between parallel sprocket chains 40 and 42 which are guided by sprockets such as the sprockets 44 and 46. The lowermost part of the screen is trained around a roll 48 mounted horizontally within the lower front portion of the suction box and connected to a driving motor 50.
At the junction of the flights 32 and 34 the feeding flight of the screen is guided around a skeletal roll 52 comprising a plurality of thin discs 54 mounted upon a horizontal shaft 56. The screen is then guided around a solid roll 58 at the end of the horizontal flight 34. At the junction of return flight portions 36 and 33 the screen is guided around a suitable roll (not shown), mounted upon a shaft 60.
The vertical wall 24 is provided with a plurality of air outlet openings 62 in each of which there is mounted a motor driven propeller 64 driven in such direction as to exhaust air from the box and create a negative pressure therein. Air is drawn into the box through the feeding and return flights of the screen. The flow of air is relatively unimpeded by the skeletal roll, but is blocked by the solid roll 58.
The feeding conveyor 12 drops the material into a chute 66 having an inclined bottom wall 68 terminating closely adjacent the lower portion of the upwardly moving feeding flight 32. The chips or other materials are thereby delivered into such proximity to the feeding flight of the screen that they may be picked up and held in a layer against the outer surface of the screen. The holding force will continue while the screen passes around the skeletal roll 52 but will be discontinued when the screen passes around the solid roll 58 in order that the material may be released to drop into the removing conveyor 14.
Situated beneath the horizontal return flight 36 is an adjusting vane 70 pivotally mounted on a shaft 72 adjacent and beneath the solid roll 58. A slotted arcuate arm 74 is affixed to the shaft '72 and a wing nut clamping de vice 76 is provided to hold the vane 70 in the desired position. The vane provides a gradual reduction of flow of air through the upper horizontal flight 34 of the conveyor as the solid roll 58 is approached. If such vane is omitted or moved to a position which is too low, there is an abrupt change in air flow through the flight 34 from a relatively high rate to substantially zero rate immediately adjacent the roll 58. The result is that air entering the top of the flight immediately adjacent the roll 58 has relatively high velocity over the top of the roll in a direction opposite the direction of movement of the flight 34. This causes particles of light weight materials to be held from movement with the conveyor. The result is a piling up of such materials on the flight 34 adjacent the roll 58 and then the discharge of large bunches of such material over the roll 58. By adjusting the position of the vane 70 the negative pressure applied to the upper flight 34 and therefore the amount of air drawn through the upper flight can be reduced to a desired value. Also, the negative pressure and the amount of such air gradually decreases along the flight as the discharge portion of the flight is approached so that the tendency for light material to pile up on the flight is largely eliminated.
The same type of problem at the upper end of the vertical or steeply inclined flight 32 is encountered if the horizontal flight 34 is omitted. It is extremely diflicult on such a vertical or steeply inclined flight to gradually reduce the negative pressure adjacent the upper end of such flight so that particles or flakes of light material are carried over the upper roll without being forced rearwardly and dislodged from the flight so that they fall downwardly. The gradual reduction of negative pressure can, however, be accomplished on a horizontal flight as explained above, and it will be apparent that such flight need not be exactly horizontal but that it may also be inclined so long as its inclination is substantially less than that of the steeply inclined flight and such that the particles or flakes will not slide downwardly thereon when the negative pressure applied to such flight approaches zero.
If the material being conveyed contains substantial moisture or other volatile liquid, it will be apparent that the negative pressure applied to such material in conjunction with the rapid movement of air past the particles of such material will produce a rapid drying action. This will result in rapid cooling of heated materials containing volatiles. For example, freshly cooked potato chips contain substantial moisture and are in a heated condition and can be rapidly cooled and dried while being elevated to the input of packaging machines. Also, flakes or other particles of cereal products which have been sprayed with a sugar solution can be rapidly dried and, if desired, heated air or other gas can be directed toward the material on the conveyor so as to be drawn through such material by the negative pressure in the interior of the suction box 16.
A different form of skeletal roll which may be substituted for the roll 52 is illustrated in FIG. 2 as comprising a hollow cylinder 80 having a plurality of closely spaced slots 82 therein. It is apparent that other types of skeletal rolls may be utilized, and it is also apparent that it may de desirable, in some instances, to position the vane 70 between the conveyor flights 34 and 36.
The conveying means 12 and 14 herein illustrated may be such as disclosed and claimed in our prior Patent No. 2,899,044, issued August 11, 1959, or may be any other suitable type of conveying means.
Having illustrated and described a preferred embodiment of the invention, it should be apparent to those skilled in the art that the invention permits of modification in arrangement and detail. We claim as our invention all such modifications as come within the true spirit and scope of the following claims.
What is claimed is:
1. An elevator for fragile, discrete materials comprising:
(a) a suction box having an open upright side and an open top,
(b) an endless screen having a steeply inclined flight spanning said open upright side and a succeeding substantially horizontal second flight spanning said open top and having a discharge portion,
() means for supporting said endless screen including a skeletal roll at the junction of said inclined and horizontal flights,
(d) means for driving said screen,
(e) means including a chute terminating adjacent the outer surface of said inclined flight for delivering materials to said elevator,
(f) means for creating negative air pressure associated with said suction box suflicient to hold materials of the above-mentioned type to the outer surface of said inclined flight,
(g) and means within said suction box for varying the negative air pressure applied to said second substantially horizontal flight as said discharge portion is approached, comprising 'a pivoted vane positioned beneath said second flight and adjustably movable to various inclinations Within said suction box.
2. In an elevator for fragile, discrete materials,
a suction box having an open upright side and an open an endless screen having a steeply inclined flight spanning said open upright side and a succeeding substantially horizontal second flight spanning said open top and having a discharge portion,
guide means for supporting said endless screen at the junction of said inclined and horizontal flights,
means for driving said screen, means for delivering materials to said inclined flight, means for creating negative air pressure in said suction box suflicient to hold materials of the above-mentioned type to the outer surface of said inclined flight, and means within said suction box for gradually reducing the negative air pressure applied to said second substantially horizontal flight as said discharge portion is approached. 3. In an elevator for fragile, discrete materials, an endless screen, means for guiding the endless screen in a steeply inclined flight upwardly to a succeeding substantially horizontal flight to a discharge point and along re turn flights to the bottom end of the steeply inclined flight and forming no substantial impediment to flow of air through any of the portions of the screen in the inclined flight and the horizontal flight, means for driving the screen upwardly along the steeply inclined flight and from the inclined flight along the horizontal flight to the return flights and forming no substantial impediment to flow of air through any of the portions of the screen extending along the inclined flight and the horizontal flight, a suction box having an opening extending continuously along the inclined flight and the horizontal flight, means for creating negative air pressure in the suction box of a predetermined magnitude suflicient to hold fragile, discrete particles on the portion of the screen traveling up the inclined flight and on the horizontal flight, and air-direction means for gradually reducing the magnitude of the negative air pressure applied to the horizontal flight proceeding toward the discharge point to a magnitude substantially lower than said predetermined magnitude at the discharge point. 4. In an elevator for fragile, discrete materials, an endless screen, means for guiding the endless screen in a steeply inclined flight upwardly to a succeeding substantially horizontal flight and along return flights to the bottom end of the steeply inclined flight and forming no substantial impediment to flow of air through any of the portions of the screen in the inclined flight and the portion of the horizontal flight adjacent the inclined flight, means for advancing the screen upwardly along the steeply inclined flight and from the inclined flight along the horizontal flight to the return flights and formin no substantial impediment to flow of air through any of the portions of the screen extending along the inclined flight and the portion of the horizontal flight adjacent the inclined flight, means for forcing air downwardly through the inclined flight and the portion of the horizontal flight adjacent thereto to press fragile, discrete particles against the portions of the screen in the upwardly inclined flight and the portion of the horizontal flight adjacent thereto, and means for gradually reducing the magnitude of flow of the air from a predetermined magnitude at the junction of the inclined flight and the horizontal flight to a substantially lesser magnitude at a point on the horizontal flight spaced substantially from the junction of the inclined flight and the horizontal flight.
References Cited by the Examiner v UNITED STATES PATENTS 1,377,136 5/1921 Lawrence et al 214-309 3,086,253 4/1963 .loa 19-1563 X SAMUEL F. COLEMAN, Primary Examiner.