US2657430A - Feeding of materials - Google Patents

Description

Nov. 3, 1953 E. J. UPTON FEEDING OF MATERIALS Filed July 11, 1951 llllD FIG.

FIG. 2.

QTUPTON ATToRu n5 fiatented Nov. 3, 1 953 FEEDING. or MATERIALS Edward James Upton, Spondon, near Derby, England; assignorto British Celanese Limited; a corporation of Great Britain Application July'l'l', 1951, Serial'No. 236129 Claims priority, application Great Britain July 19, 1950 1. This invention relates: to the feeding of ma terials, and particularly to the feeding Of'DOW- dered or granular solid materials, and hasfor its object the provision of a method and: apparatus for the feeding of suchmaterials in which jamming or bridging of a stream of solid material supplied to a receiving space is avoided;

According to thepresent invention a method of feeding powdered or granular material comprises causing the material to flow by gravity down a passage into a receiving space, subjecting the level of the material in said space to the intermittent feelingaction of an oscillating member and, when said level is low, using. the excess motion of said member consequent upon such lownessto'eflect a movement of the boundaries of said passage-seas to encourage theflow of material down said passage; An apparatus for carrying out this method comprises a downwardly extending duct for the flow of material into a receiving space, a feeler member, means for oscillating said member into and" out ofcontact with the surface of: the powdered or granular material in said receiving space, and means for transmitting excess motion of said member, be-

yond a predetermined range'of oscillation, to the boundaries of said duct. The excess motion which is made use of in thisway maybe either the excess at that end: of 'therangeof oscillation at which feeling takes place, or it may be an. ex-

cess of motionby way of reactionat theother end of the range, or use may be made of the excess motion at both ends.

By the use of the method and apparatus defined above, disadvantages arising from the tendency of powdered or granular material flowing through a passage to assume a meta-stable state in which the flow is inhibited. by a jamming or bridging of the particles ofmaterial" across the passage, are substantially overcomeby disturbing such state whenever the space suppliedis starved of material" by reason thereof. It may be observed that any kind of movement of the boundaries of the passage will be effective in disturbing the jammed condition of the material though it is usually undesirable to employ movements which have the additional efiect of closing or restricting the cross-section of the passage. Thus the movement may be of the nature of a mere vibration of the duct carrying the passage, either laterally or longitudinally of the passage. Preferably, however, the movement is such as to enlarge the passage through the duct momentarily and to bring about a flow of material greater than average to make up the deficiency 1 Claim'.. (Cl. 18-30).

2 originally causing the movement. Thus, the normal flow of material: may be controlled. by a constriction in the duct, e. g..a gate extending partway across it, and the movement taking place upon jamming or bridging of the material may consist of an opening. of the gate or other con striction. The average rate of flow of the ma-- terial along the ductmay: be such: as to callfor a continual movement of the boundaries of the passage, such movements varying in. extent, however, in accordance. with the: level of material in the space supplied.

In. cases where the-.furtheruse-or destination or materials supplied to: the; space is such as to require the employment of a member in the space for some other'purpose; than detecting the level of the material. therein, e. g. to encourage. the movement of the material in the space or to tamp the material into" a; compact mass, use may be made of such member for the purposes of the present invention. For this purpose" the member should'be arranged so that the extent of" its movement depends upon the level of the, material in the. space, whereby the variation of the movement arising from: changes; in that level can be.

made use of.

Thus, the invention; is of particular advantage in connection. with the processes and apparatusdescribed in U- application S. No. 115,635, filed: September 10,1949, in which, for-the purpose of extruding" a: fusible filament-forming, material supplied. in. powdered or granular form, the material is fed into a zone laterally bounded by moving surfaces which lie parallel to their direction of motion andiscompacted in saidzone intov a. coherent rod" which is advanced with said surfaces- The. compacting of the material into a coherent rod is conveniently effected by means of" a: tamping rod vibrating longitudinally in the zone, and use may be made of the variations in the amplitude of the'vibrations of the camping rod, consequent on variations in the: level of the materialz contained, in the zone, for. the purposes,

of the present invention.

By way of example, one form of apparatus in accordance with the present invention, in its application to the method and apparatus generally described in U. S. application S. No. 115,035, will now be described in greater detail with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic sectional side elevation of an apparatus according to U. S. application S. No. 115,035, and,

Figure 2 is a front elevation of part of the apparatus of Figure 1 showing the feeding means.

In the above specification an apparatus is described which is of the kind shown in Figure 1 and comprises a pair of flexible bands each having a straight operative run opposite to the operative run of the other so that they constitute, in conjunction with two stationary surfaces II extending from one band H! to the other, a parallel-sided passage 12 of rectangular crosssection having two moving walls constituted by the bands I0. Each band It) is supported by a chain of articulated blocks 13 which pass round pulleys l4 and a sprocket l5 and are continuously driven by means of the sprocket IS. The bands in are kept taut by means of jockey pulleys l6. Along the length of the parallel-sided passage 12 the blocks I3 are solidly supported by members I1, and into the early part of the passage 12 enters a longitudinally vibrating tamping rod l8 of rectangular cross-section loosely fitting the passage [2 and actuated by a pneumatic vibrator unit l9. At about the mid-position of the tip 29 of the tamping rod two oblique feed passages 22 communicate with the passage l2. The rod I8 is shown in its uppermost position in Figure 1, in which the mouth of the passage 22 is uncovered, and in its lowermost position in Figure 2. The feed passages extend through the stationary surfaces ll. Through the feed passages 22, powdered or granular material is supplied to the passage [2, and is tamped into a co1npacted rod by the action of the tamping rod l3. Since the compacted material is carried away by the moving bands H1 at a substantially constant rate, it is necessary that fresh powdered or granular material should be fed through the feeding passages or ducts 22 at a substantially constant rate in order that the resulting rod should be uniformly compacted. It is for this purpose that the apparatus of the present invention is employed.

Across each of the ducts 22, as shown in Figure 2, shortly before they enter the rectangular passage l2, there extends from above a sharpedged plate or gate 24, the upper part of the duct 22 being slotted for its reception. The two gates are connected together by a yoke 25 between their upper edges, which lie at a convenient distance above the uppermost points of the flexible bands ID. The yoke 25 is centrally bored at 23 to allow the vibrating tamper rod ii! to extend through it, and is slidably mounted in slots 27 formed in the standards 28 which carry the vibrator unit [9 actuating the tamping rod I8. The yoke 25 is urged downwards, to the bottom of the slots 21, by means of a light spring 29 abutting against the vibrator unit and, in this position, the lower edges of the gates 24 extend sufiiciently far across the ducts 22 to limit the flow of granular material to a rate approximately sufficient for the feeding of the rectangular passage l2. This position of the gates can be adjusted by adjusting the connection of the upper edges of the gates to the yoke. The gates are secured to the yoke by means of screws 30 passing through vertical slots in the gates which enable this adjustment to be made. In the bore of the yoke is adjustably screwed a tube 32, which can be locked in position by means of a screw-threaded locking ring 33. Extending laterally from the tamping rod l8 are two shoulders 34 adapted, when raised to a sufficient height, to engage the lower edge of the tube 32 and so to lift the yoke 25 and the gates 24 carried thereby.

In the operation of the apparatus described, the powdered or granular material flows through the ducts 22 into the rectangular passage 12 and is there compacted into a coherent rod of rectangular cross-section which is steadily carried away by the motion of the flexible bands ii). In the event of jamming of the powdered or granular material in either of the ducts 22, the rectangular passage I2 tends to be starved of material and the tamped upper surface of the material therein falls. This permits a greater freedom of oscillation to the tamping rod l8 and, as it descends further before engaging the surface of the material, so it reacts to a higher level in the course of its upward movement. This causes the shoulders 34 carried by the tamping rod ill to engage the tube 32 carried by the yoke 25 and to lift the gates 24, thereby breaking the jam of powdered or granular material and momentarily permitting a more than usually rapid rate of supply to make up the deficiency. When the deficiency is made up, the range of vibration of the tamping rod I8 is again restricted, and the gates 2 t across the ducts 22 occupy their normal position undisturbed.

Having described my invention, what I desire to secure by Letters Patent is:

Apparatus for the feeding of powdered or granular material, said apparatus comprising a downwardly extending duct for the fiow of material into a receiving space, a gate adapted to extend partly across said duct, a feeler member, means for vibrating said member into and out of contact with the surfaces of the powdered or granular material in said receiving space, with a restoring force variating with its displacement from a standard position, and means for transmitting excess motion of said member away from said surface beyond a predetermined distance from said standard position of said gate so as to open said gate momentarily.

EDWARD JAMES UPTON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,033,735 Pack Mar. 10, 1935 2,198,713 Wacker Apr. 30, 1940 2,202,269 Ryder May 28, 1940 2,317,331 Mearig Apr. 20, 1943 2,371,060 Menger et a1. Mar. 6, 1945

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