US2361253A - Processing of materials - Google Patents

Description

Oct. 24, 1944. E. L. WIEGAND PROCESSING OF MATERIALS Original Filed Dec. 7, 1939 w; %W W I L 3 f q 3 J. M iv a? M PROCESSING OF MATERIALS Edwin L. Wiegand, Pittsburgh, Pa., assignor to Orefraction Incorporated, Pittsburgh, Pa., a corporation of Pennsylvania Original application December 7, 1939, Serial No. 308,002. Divided and this application October 25, 1940, Serial No. 362,766

8 Claims.

My invention relates to the processing of materials, and more particularly, the conveying of materials, the grinding of materials, and the eparation of co-mingled material particles. The principal object of the invention is the improvement of apparatus for carrying out such processing of materials. This application is a division of my application Serial Number 308,002, filed December 7, 1939.

In the drawing accompanying this specification and forming a part of this application, there is shown, for purposes of illustration, one embodiment of apparatus embodying the invention, and in this drawing:

Figure 1 is a more or less diagrammatic view of the relation between material conveying means, grinding means, and separating means, as these means may be utilized in one embodiment of my invention.

Figure 2 is a sectional view of a material hopper and control device, and

Figure 3 is an electrical diagram of a control circuit.

The term material i used herein to include any substance of a divided nature, as distinguished from relatively large blocks of substances. The term grinding is used herein in its broader aspects as meaning reduction in size, in any way, of the material being treated, and in its more specific aspects, such grinding as occurs when material is subjected to impact. EX- amples of material which may bFgro'iiiid by an apparatus embodying my invention are such materials as zircon, rutile, quartz, feldspar, fluorspar, marble, glass, enameling frit, hard metals, artificial or other abrasives, industrialldiamonds, and many others either of similar or different characteristics. The invention of the present application is shown as it may be used in connection with the reduction of, particularly, hard, tough, and abrasive materials, including ores having these characteristics. The illiistfati'if embodimefitisparticularly adapted to grind material to ultra-fine sizes, such as for example 200 mesh to micron sizes, and in this embodiment the material to be ground preferably should not be larger than 16 to 18 mesh size, although it is possible to accommodate larger sizes. In

general the size to be commenced with in'this embodiment may be any desirable size which cannot be better or more economically crushed otherwise, but since in this embodiment the material is projected through a gun, the size of the material to be ground is related to gun size, and therefore also to the capacity of the apparatus.

Referring to the schematic arrangement shown in Figure 1, the embodiment of the invention there illustrated comprises a container adapted to contain material to be ground, and hereafter referred to as the new-materials container. The new-materials container 50 may be formed with an outlet spout 5| discharging into a funnel 52 carried by the receiving end 53 of an elevating device 54, such as the bucket elevator here shown. Asuitable slide valve 55 is interposed in the outlet spout 5| to regulate the flow of material from the new-materials container 50 to the receiving end 53 of the elevator 54. The elevator. 54 may be driven by means of an electric motor 56, and may also have a signal device, such as the electric light 51, to indicate when the elevator 54 is op rating. The discharge end 58 of the elevator 54 ischarges into a conduit 59 leading to a blending and metering hopper 60, desirably provided with an inclined false bottom 6011 (Figure 2), and having high and low limit controls 6| and 62, so as to control operation of the motor 56 of the elevator 54, the connections being such that the motor 56 of the elevator 54 is automatically started when the level of the material fall below the low level device 62, and the motor 56 is automatically stopped when the material rises up to the high level device 6|.

Preferably, the high level control 6| comprises a rotatable housing disposed at the outside of the hopper 60, the housing containing a mercury switch 645 (Figure 3). One terminal of the switch 645 is connected to a conductor 660 leading to a source of electricity (not shown), the other terminal being connected to one terminal of the motor 56. The other terminal of the motor 56 is connected, through a switch 658, to a conductor 656 leading to the source of electricity. The housing BI is rotatable in one direction by a vane Gla within the hopper 60 (see Figure 2). The low level device 62 comprises a pivoted vane 6211, within the hopper 60, urged counterclockwise, as viewed in Figure 2, by a counterweight 62b. The vanes 6Ia and 62a are shown in Figure 2 in the position they occupy when the hopper 60 is full of material, a indicated by the upper dotted mound line M, the vane Bla standing about 45 counterclockwise to the right of the vertical and the vane 62a about 45 clockwise to the left of the vertical. The vanes 6Ia and 62a are shown as connected by a lost motion connection which includes a rod 620 disposed at the outside of the hopper 60, pivoted at its lower end to a crank 62d movable in unison with the vane 62a, and having at its upper end a slot with which cooperates a pin on a crank 62e movable in unison with the vane am.

Withdrawal of the material from the hopper 60 causes the surface of the mound of material to fall, but for the time being the vane 6la, by friction adjustment of its shaft, remains in the position shown in Figure 2, even though the surface of the mound adjacent the vane Bla recedes away from that vane. When the mound of material decreases in height so that its surface adjacent the vane 62a recedes sufiiciently away from that vane, the counterweight 62b causes counterclockwise rotation of the vane to a position about 45 counterclockwise to the right of the vertical, such movement being transmitted through the lost motion connection so as to move the vane Gla clockwise to a position about 45 to the left of the vertical, thus moving the mercury switch 645 to its on position, in which position it completes the circuit through the motor 56, whereby material is delivered to the hopper 60 by the elevator 54.

When the mound of material in the hopper increases, either by reason of delivery by the elevator 54 or otherwise, as will appear hereinafter, the material acts against the vane 62a and eventually moves the vane 62a clockwise, into the position shown in Figure 2, against the urging action of the counterweight, when the mound reaches the height indicated by the lower dotted mound line 112. However, such movement of the vane 62a will not affect the vane Bla because of the lost motion connection therebetween. When the mound of material rises enough, the material will act against the vane 6la and eventually move it counterclockwise to the position shown in Figure 2, when the mound has increased to the upper dotted mound line M, thereby causing rotation of the mercury switch 645 to its off position, and thus interrupting the circuit of the motor 56.

Positioned alongside of the receptacle 60 is a second elevator 63, having its inlet end 64 receiving material from the lower end of the hopper 60, as by means of a conduit 65, a suitable slide valve 66 being so interposed as to control the amount of material flowing from the hopper 60. The elevator 63 is driven by an electric motor 61, and may have a signaling device, such as the electric light 68, to indicate when the motor 61 is running. The discharge end 69 of the elevator 63 leads to the inlet of a solids valve 10 the outlet of which communicates with the interior of a charge metering and hoist tank H. The hoist tank H has high and low level devices 12 and 13 respectively, so related to other parts (as described in my aforesaid application) as to permit the motor 61. to operate when the material is below the low level device 13, and to interrupt the circuit of the motor 61 when the material reaches the high level device 12.

A fluid under pressure, in the present instance, air, may be admitted to the hoist tank 'll through a conduit 14, and such air may be released from the hoist tank H through either the conduit 14 or a blow-off conduit 15. With material in the hoist tank H, and air under pressure supplied to the hoist tank H through the air conduit 14, the material in the hoist tank H is forced to move into the lower end of a tube 2l9 suitably connected at its upper end to and in communication with a conduit 16, the material continuing through the tube 2l9, through the conduit 16 to a connection conduit 11 between an air strainer tank 1.8 and an upper material feed tank 19, a valve being interposed in the connection conduit ,TI to permit admission of material to the upper tank 19 and to enable the tank to be placed 2 2 fluid. PI9I bin B'fi'i'ipo'sition, the material which passes through the conduit 1B is delivered to the connection conduit 11, the ai r us e d f o r hg stip g pl ire -strained..bx. nmventesl..ire zz...th

flow of material from'the lower tank B L Means (not shown) is provided for admitting air under pressure to the upper andlower tanksfl' and 8 I.

Assuming that the valve 83 is' 'cldsed'ahd"tlie valve 85 is open, and' assuming also that material is in the lower tank 8|, and that this tank is unwilllbe'forced through the outletconduittfl, and hr u a e. conduit mo. ehreaell ti on: gurf'88', and through this gun 88 to'the grinder "case-89, the material being projected from the muzzle of the gun in the grinder case and subjected to impact in any desired way. The ground material passes through a conduit 90 to a first separating device 9i of the cyclone type. 1% surfaces in the device 9| wh ig h mightbe subject to abrasive weai iii aybe'siii'tably lined witlf rubber. Theheavier material in'th'e first separating device 9| may gravitate through a tube 5' against a check valve 92, this valve being so constructed and arranged that a predetermined head of material is built up and maintained at the discharge end of the separating device 9|, material being permitted to gravitate past the check valve, into the conduit 93, as further material accumulates in the discharge end of the separating device- Any suitable check valve may be used and instances are described in my aforesaid application. .The material then continues through the conduit 93 .to a funnel 94, and from the funnel 94 to a screen chamber 95 of a screening device 96. j

The screening device 96 may be of the vibrating type, having a screen 91 over which the material is shucked, the screen having a certain predetermined mesh size, as for example 200 mesh.

The material which passes through the screen 9'! falls into a hopper 98, the outlet of the hopper 98 having a bagging device 99, to which a bag I00 is attached, the bag I00 receiving such material for shipment if desired. For convenience, the bag I00 may be disposed on a platform IOI of a scale I02, so that the amount of material delivered to the bag I00 may be weighed as it is delivered to the bag. That material which does not pass through the screen 91 is discharged from the screen chamber 95 through a conduit I03, and'back to the mixing hopper 60. Additional material, from the new-materials container 50, may be added to the hopper 60 by means of the elevator 54, the high level device 6| limiting the amount of new material delivered to the hopper 60. In this manner the material removed from the system is automatically replaced With new material from the new-materials Assuming the valve 90 to container 50. The slide valve 55 may be adjusted to a particular flow rate, such rate being determined by the rate at which finished material is removed from the system.

Additional separating means is provided for additionally separating that material which does not gravitate from the first separating device 9|, and this means comprises, among other parts, a pump, in this instance a blower fan I04, disposed within a fan chamber I and driven by an electric motor I06. The outlet of the fan chamber I05 is branched, one branch I0I leading to the atmosphere, and the other branch I08 being connected to one end of a conduit I09, the opposite end Il0 of the conduit I09 leading tangentially into the first separating device 9|, if desired in two diametrically disposed tangential branches H00. and H01). Slide valves III and I I2 are respectively interposed in the branch conduits I0! and I08, these valves being independently adjustable so as to regulate the amount of air discharged by the blowersthrough the respective branch, for a purpose to appear.

The upper discharge outlet of the separating device 9I is connected to the inlet of the blower chamber I05, and in this instance certain devices are interposed in this connection. Extending from the upper discharge outlet of the first separating device 9! is a separating column, H3, of any suitable cross-sectional form, area, and length, which extends vertically and is connected to a conduit I M which is tangentially connected to the upper end of a second air separating device II6. Desirably the separating column II3 is enlarged with respect to the conduit H4, and may taper toward its lower end to cause hindered settling. The device II6 may be of the cyclone type, comprising a chamber having an upper cylindrical portion I I1 and a downwardly tapering conical portion II8. A bagging device H9 is connected to the lower end of the conical portion H8, and has attached thereto a bag I20 for receiving material gravitating downwardly of the conical portion H8. The upper end of the second separating device H6 is formed with a housing I2I communicating with the interior of the device H6. The housing I2I communicates by means of a conduit I22 with a dust collector or separator I23, which may be of any suitable type. The lower end of the dust separator I23 has attached thereto a bagging device I24, and the air outlet of the dust separator I23 is connected by a conduit I25 to the inlet of the fan chamber I05.

Assuming that the motor I06 is operating, and that the valve I I I is at least partially open, and that ground material, along with air used in grinding it, is being delivered through the conduit 90 to the first separating device 9|, the material which under the air conditions prevailing in the separating system is not heavy enough to gravitate at once from the separating device 9I, will be picked up by the stream of air in the column II Some of this material will continue to be carried by that stream to the top of the column II3 and through the conduit IM to the upper end of the second separating device H6, and will be caused to swirl in this upper end because of the tangential connection of the conduit H4. The heavier materials in the second separating device II6 will gravitate downwardly through the conical portion II3, and will be delivered to the bag I20 through the bagging device II9. The lighter material will be carried upwardly by the air stream through the housing I2I and the conduit I22, to the dust collector I23, where the dust will be separated from the air, the dust particles being discharged from the bottom of the dust separator I23 and to the bagging device I24, and the air passing to the conduit I25 and back to the inlet of the blower chamber I05. Some of the material which enters the separating column II3 from the separating device 9I does not continue with the upwardly moving stream of air into the conduit 4, but gravitates back through the stream into the separating device 9| and finally reaches the lower or discharge end of the separating device 9I, and thus the separating action of the system is improved.

Depending upon the setting of the slide valves I I I and I I2, either an under-pressure or an overpressure condition (with respect to atmospheric pressure) can be made to exist in the first separating device 9|. Usually the valve H2 is partially or completely closed, and the valve I I I partially or completely open, so that an under-pressur or partial vacuum exists within the first separating device 9I and in the column II3, whereby material readily passes from the grinder case 89 to the first separating device 9|, and no back pressure is created in the conduit 90 leading from the grinder case 89. Also, usually the valves III and H2 are adjusted to efiect substantially zero (atmospheric) pressure in the grinder case 89, thereby to avoid back pressure in the grinder case 89 that might interfere with the operation of the grinder gun. However, it will be apparent that the pressure conditions in the grinder case and in the separating system can be regulated by adjustment of the slide valves II I and H2 to obtain any desired pressure conditions. Furthermore, the velocity of the upwardly moving stream of air in the separating column II3 may be adjusted to a most suitable velocity so that the separating function of the column I I3 will be optimum.

Since a certain head of material is maintained within the tube 5'II by the valve 92, air communication between the conduits '93 and the interior of the first separating device 9I is prevented. Thus the pressure condition within the device 9|, either greater or less than atmospheric pressure, as may be desired, will not changed, since the check valve 92, either open or closed, substantially prevents flow of air through the tube 51 I The first separating device 9| may be moved from the position shown in full lines in Figure 1 to the position shown in dotted lines, wherein its lower end no longer communicates with the conduit 93, but instead communicates with a conduit I35 leading to a tank I36, hereinafter referred to as a by-pass tank. The lower end of the tank I36 carries a bagging device I31, to which a bag I38 may be attached, and a check valve I39 is interposed in the conduit I35, the check valve I39 being provided for the same purpose a the check Valve 92. In this position of the device 9I, the ground material, excepting only a controllabl amount and size of very fine material, instead of going to the screen chamber 95, passes directly to the by-pass tank I36. The conduit I I3 in this position may still be connected to the conduit 4. The by-pass tank connection is particularly useful when it is desired to make an unscreened ground aggregate, with only a minimum of extreme fines removed.

The valve is closed. when initially charging the apparatus, and may also be closed for interrupting the process temporarily without relieved pressure on the lower feed tank 8|, or at the end of a run prior to a subsequent initial charging or beginning of operations. In other words, it is closed before initially charging, or at the end of a days run, or for temporary interruption, and it is opened when beginning operations, as at the beginning of a day, or after an interruption as for inspection or adjustment of other equipment.

While the material in the lower feed tank 8| is being ground, the hoist tank "II will have again been filled, with either new material or with a mixture of new and partly ground material from overage from the screen 96, and this charge will have been hoisted, and all is in readiness to dump the same into the tank 8| when a low level responsive device (not shown) in the lower tank 8| indicates sufficient evacuation to receive the next charge from the upper feed tank 19.

From the foregoing description of the apparatus and the operation thereof, it will be apparent that operation of the apparatus and process are enabled to be continuous, but interruptable when desired.

It will be evident that the illustrated apparatus embodies features which are particularly applicable to the handling of finely divided material or dust, these features providing a closed system from which no dust can escape to the ambient air. It also will be evident that though certain features are especially adapted for the handling of material in a grinding system and, more particularly, a continuous grinding system, the use of these features is not limited to either of these purposes.

From the foregoing it will be apparent to those skilled in the art that the disclosed apparatus embodying my invention provides a new and improved apparatus for processing of materials, and accordingly accomplishes the principal object of my invention. On the other hand, it also will be obvious to those skilled in the art that the disclosed embodiment of my invention may be variously changed and modified, and features thereof, singly or collectively, embodied in combinations other than that disclosed, without departing from the spirit of my invention or sacrificing the advantages thereof, and accordingly, that the disclosure herein is illustrative only, and that my invention is not limited thereto.

I claim:

1. In means for feeding material to a grinding means; a tank; primary means for feeding material to said tank; means for conveying material from said tank to the grinding means; means for separating a coarse fraction of material from the product of said grinding means; means for conveying said coarse fraction to said tank; and means for automatically starting and stopping said primary means in response to the amount of material in said tank.

2. In means for feeding material to a grinding means; a tank; primary means for feeding material to said tank; means for conveying material from said tank to the grinding means; means for separating a coarse fraction of material from the product of said grinding means; means for conveying said coarse fraction to said tank; means for automatically starting and stopping said primary means in response to the amount of material in said tank; and means for controlling the rate at which said primary means while in operation feeds material to said tank.

3. In means for feeding material to a grinding means; a tank; primary means for feeding material to said tank; means for withdrawing material from said tank and conveying it to the grinding means; means for controlling the rate of withdrawal from said tank; means for separating a coarse fraction of material from the product of said grinding means; means for conveying said coarse fraction to said tank; means for automatically starting and stopping said primary means in response to the amount of material in said tank; and means for controlling the rate at which said primary means while in operation feeds material to said tank.

4. In means for feeding material to a grinding means; a tank; primary means for feeding material to said tank; means for conveying material from said tank to the grinding means; means for separating a coarse fraction of material from the product of said grinding means; means for conveying said coarse fraction to said tank; level responsive means comprising means responsive to a low level of material in said tank and means responsive to a high level of material in said tank; control means movable in response to said level responsive means; means whereby said control means controls said primary means; and said level responsive means being so constructed and arranged that said control means causes operation of said primary means when the material in said tank decreases to a predetermined low level and causes said primary means to continue in operation until the material in said tank increases to a predetermined high level and thereupon causes said primary means to cease operation until the material in said tank again decreases to said predetermined low level.

5. In combination: a tank for containing material to be ground; grinding means; primary means for feeding material to said tank; means for conveying material to said grinding means only from said tank; means for separating a coarse fraction of material from the product of said grinding means; means for conveying only said coarse fraction to said tank; and means for automatically starting and stopping said primary means in response to the amount of material in said tank.

6. In combination: a tank for containing material to be ground; grinding means; primary means for feeding material to said tank; means for conveying material to said grinding means only from said tank; means for separating a coarse fraction of material from the product of said grinding means; means for conveying only said coarse fraction to said tank; means for automatically starting and stopping said primary means in response to the amount of material in said tank; and means for controlling the rate at which said primary means While in operation feeds material to said tank.

7. In combination: a tank for containing material to be ground; grinding means; primary means for feeding material to said tank; means for withdrawing material from said tank and for conveying to said grinding means only material so withdrawn; means for controlling the rate of withdrawal from said tank; means for separating a coarse fraction of material from the product of said grinding means; means for conveying only said coarse fraction to said tank; means for automatically starting and stopping said primary means in response to the amount of material in said tank; and means for consponse to the amount of material in said tank, said automatic means comprising, means responsive to low level of material in said tank, means responsive to high level of material in said tank, control means movable in unison with said high level responsive means, and means whereby said low level responsive means is adapted to control said high level responsive means.

EDWIN L. WIEGAND.

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