US3424388A - Apparatus for crushing and sorting solid particles - Google Patents

Description

R. A. REICHEL Jan. 28, v1969 APPARATUS FOR CRUSHING AND SORTING SOLID PARTICLES Sheet 012 Filed July 25, 1966 ONTROL CIRCUI INVENTOR. RICHARD A. REICHEL ATTORNEYS Jan. 28, 1-969 7 R. A. REICHEL 8 APPARATUS FOR CRUSHING AND SORTING SOLID PARTICLES Filed July 25, 1966 Sheet 2 of 2 33 J I I5 SENSING 03 0 46 47 COIL A.

45 MIXER, DET

44 v 'TG I I FI J GI 52 42 37 I 7 v H /4| \JUUI R"" C2 Ql INVENTOR. RICHARD A. REICHEL ATTORNEYS United States Patent 7 Claims Int. Cl. B02c 13/00 ABSTRACT OF THE DISCLOSURE Apparatus for sorting minerals with a metallic content above a given value from minerals whose metallic content is below that given value. Sample minerals to be sorted are fed from a conveyor to the central region of a rotating table that impels the minerals under centrifugal force through a plurality of radially aligned passages. Minerals with metallic content above the given value are automatically detected by electronic sensors which cause doors mounted at the exit ends of the passages to swing downwardly and deflect the minerals into an inner annular receiving chamber. In the case of other minerals, the deflecting doors remain in retracted positions enabling the minerals to pass into an outer receiving chamber concentrically aligned with the inner one. Oversized minerals are crushed by a rotatable inertial plate positioned above the table.

This invention relates generally to sorting apparatus and more particularly to a novel mineral sorting apparatus for separating into at least two groups, pieces of mineral differing from each other in accordance with a given characteristic.

Many mineral sorting systems are presently known in the art. Basically, these systems function to automatically separate minerals into various categories according to their size, specific gravity, or other physical or magnetic characteristic.

In those cases in which it is desired to separate pieces of mineral which have no significant physical or magnetic properties different from the pieces of waste rock much more complex equipment is required. Some of the problems involved include the provision of suitable means for enabling a piece-by-piece sensing of the mineral and the separating of the same in accordance with the particular characteristic for which the structure is designed. The piece-by-piece sensing of the pieces of mineral itself raises various problems which include, among others, the design of a system wherein a large volume of 'mineral pieces can be sorted in a relatively short period of time without requiring an enormously bulky apparatus, the problem of assuring that the pieces of mineral to be analyzed do not exceed a certain size which might jam the sensing mechanism, and the provision of a sensing means sufficiently responsive to the desired characteristic to minimize errors in sorting. Of these problems, that dealing with a system enabling a piece-by-piece analysis to take place and yet handle a large volume of minerals in a relatively short period of time without undue bulk and expense is one of the most important.

With the foregoing considerations in mind, it is a primray object of the present invention to provide a novel mineral sorting apparatus in which the above problems are resolved to a considerable extent.

3,424,388 Patented Jan. 28, 1969 "ice More particularly, it is an object to provide a novel mineral sorting apparatus capable of effecting a piece-bypiece analysis of minerals and separating the same into at least two groups in an extremely rapid manner and without undue bulk.

Another important object is to provide a mineral sorting apparatus incorporating unique means for limiting the size of pieces of mineral to be analyzed so that the risk of stopping or jamming of the apparatus is minimized.

Still another important object is to provide, in combination with a sorting apparatus meeting the foregoing objects, a unique electronic sensing system which is sufficiently sensitive as to enable separation of minerals in accord with their metallic content.

A more general object along the lines of the preceding object is to provide a mineral sorting apparatus so designed that different types of sensing equipment may be substituted to enable separation of pieces of mineral in accordance with characteristics diflerent from their metallic content, such as their color or other optical, electrical, radiation, chemical, or physical properties.

Other objects of this invention are to provide a mineral sorting apparatus which may be easily monitored while in operation, and which is relatively economical to construct, compact in size, and extremely rugged in design and construction to the end that it will provide long and trouble-free service.

Briefly, these and many other objects and advantages of this invention are attained by providing a basic rotary means mounted for rotation about a vertical axis and defining a plurality of passages having entrance ends adjacent to the central portion of the rotary means and exit ends adjacent to the periphery of the rotary means.

Raw mineral pieces are passed into the central portion of the rotary means such that minerals received in this portion are caused to travel along the passages individually by centrifugal force upon rotation of the rotary means. By providing several such passages on a single rotating structure, several pieces of mineral may be analyzed simultaneously.

At the exit ends of each of the passages, there is provided a deflecting means and a suitable control means including a sensing means for actuating the deflecting means. When apiece of mineral, which has a characteristic different from other pieces of mineral in accordance with the desired separation or grouping of the mineral pieces, passes the sensing means, the sensing means actuates the deflecting means to deflect the particular piece of mineral in question as it is thrown from the exit opening of the passage into a suitable receiving chamber.

There is thus provided a separation of pieces of mineral having a given charatceristic from the remaining pieces of mineral.

In the preferred construction of the sorting apparatus, there is provided an outer shell and inner shell structure defining an outer annular receiving chamber which surrounds the peripheral exit ends of the various passages in a position to receive pieces of mineral that are not deflected. The inner shell serves to define an inner chamber which will in turn receive pieces of mineral that are deflected. The annular shell structures are generally coaxial with the vertical axis of rotation of the rotary means resulting in an overall compact configuration for the entire sorting apparatus.

A better understanding of the invention as well as further unique advantages and features will be had by now referring to a preferred embodiment thereof as illustrated in the accompanying drawings, in which:

FIGURE 1 is a perspective view, partly broken away, of the mineral sorting apparatus of this invention shown in conjunction with a conveyor belt for passing minerals to the apparatus;

FIGURE 2 is a partially exploded, broken away, perspective view of the structure illustrated in FIGURE 1;

FIGURE 3 is a fragmentary plan view looking generally in the direction of the arrows 33 of FIGURE 2;

FIGURE 4 is an enlarged fragmentary perspective view of a portion of the structure illustrated in FIGURE 3 looking in the direction of the arrow 4;

FIGURE 5 is a greatly enlarged fragmentary view partly in cross section of the sorting apparatus;

FIGURE 6 is a schematic circuit diagram of the sensing and actuating means employed in the sorting system; and

FIGURE 7 shows an automatic tuning circuit.

Referring first to FIGURE 1, there is indicated generally by the numeral 10 the mineral sorting apparatus wherein there is provided an entrance opening indicated by the arrow 11 for receiving pieces of mineral 12 from a conveyor 13. As shown, the pieces of mineral are dropped onto an upper conical wall 14 in an upper outer shell structure 15 of the apparatus.

The lower portion of the apparatus is comprised of an outer lower shell 16 including outlet tubular structures 17 and 18 for passing separated pieces of mineral into suitable containers such as indicated at 19 and 20.

In the particular embodiment to be described, the pieces of mineral 12 are separated into two groups in accordance with a given characteristic such, for example, as their metallic content. However, it is to be understood that any other type of given characteristic may be controlling such as physical, optical, or chemical properties of the mineral pieces in question.

Referring now to FIGURE 2, further details of the structure will be described. As shown, the 'funnel opening 14 merges into a cylindrical tubular portion 21 upon which is rotata'bly mounted an inertia plate 22 having downwardly directed projections 23 and 24, the purpose for which will become clearer as the description proceeds. The lower portion of the structure includes an inner shell 25 cooperating with the outer shell 16 to define an outer annular receiving chamber 26. This annular receiving chamber 26 communicates with the tubular structure 17 as shown. The inner shell 25 also defines an inner receiving chamber 27 which communicates with the tubular outlet structure 18, as shown.

The outer and inner receiving chambers surround a rotary means in the form of a rotary table 28 on the surface of which there are defined a plurality of passages preferably extending generally radially in an arcuate manner as indicated at 29. The rotary table 28 is mounted for rotation on a shaft 30.

It will be noted from the plan view of FIGURE 3 that the various passages 29 are all identical and are designed such that when the rotary structure is rotated in the direction of the arrows, pieces of mineral received in the central portion of the rotary structure will be caused to travel radially outwardly along the passages by centrifugal force.

Referring now particularly to FIGURE 4, one of the passages 29 will be described in detail. Since these passages are all the same, description of one will suifice for all. As shown, the passage includes an entrance and 31 adjacent the central portion of the rotary structure and an exit opening 32 adjacent the periphery of the rotary structure. At this exit portion of the passage, there is provided a deflecting means preferably in the form of an overhead door 33 hinged to the upper end edge of the exit end 32 as shown. Door 33 is normally held in an horizontal outwardly extending position as by a biasing spring 34. The position of the door 33, as shown, constitutes a first position.

The door 33 is arranged to be moved to a second position by a solenoid actuated structure 35 in response to a suitable signal derived from a sensing means including a sensing coil 36 constituting part of a control circuit 37. It will be noted that the sensing coil 36 is positioned adjacent the exit end 32 of the passage in such a manner that pieces of mineral passing down the passage 29 will pass close to the coil structure 36.

The foregoing design is such that when the solenoid structure 35 is energized, the door 33 will be swung downwardly towards a partially closed position in which its inside surface will constitute a deflecting surface to deflect any pieces of mineral passing down the passage 29 to the inner receiving chamber 27. When the door is in its first or outwardly extending position illustrated in FIGURE 4, any pieces of material thrown from the exit end 32 of the passage will pass over the inner receiving chamber 27 and be received in the outer annular receiving chamber 26.

Referring now to FIGURE 5, the foregoing as well as other features of the invention will be better understood.

As shown in FIGURE 5, the inertia plate 22 referred to in FIGURE 2 is mounted as by bearings 38 for free rotational movement about the tubular portion 21 of the entrance opening 14 in the upper shell 15. It will be noted that the projections 23 and 24, which may be in the form of rigid metallic bars welded to the underside of the inertia plate 22, terminate a given distance above the floor of the rotary table 28. This given distance is slightly less than the exit opening dimensions for the various passages such that over sized minerals received in the central portion of the rotary means and thrown outwardly towards the entrance end of the passages as by centrifugal force will be engaged by the projections 23 and 24. This engagement causes the inertia plate 22 to rotate but because of its inertia, the mineral piece is crumbled or crushed, and any other pieces engaged by the projections 23 and 24 are similarly crushed or broken in size such that they will readily pass down the various passages. It is to be understood that the bearings for the inertia plate permit vertical as well as rotational movement so that damage to the apparatus is prevented.

With respect to the foregoing, an important feature of the inertia plate is that it will simply rotate with the rotating passages in the event that a non-crushable object such as a large piece of steel is fed to the apparatus. Continuous rotation of the inertia plate can be sensed to automatically stop the feed to the machine and thus prevent further jamming. Suitable brushes indicated generally by the number 40 pass from a stationary power supply 41 to the slip rings 39 to regulated power supplies 42 to provide energy for these particular circuits. Electrical signals which indicate the operational condition of each sensing means also are transmitted through the slip rings. In this respect, it will be evident that the passages individually include control circuits, sensing means, and solenoid actuated deflecting means all carried with the rotary table 28 along with the regulated power supplies 42 so that the same rotate with the rotary structure.

With the foregoing description of FIGURES 1-5 in mind, the overall general operation of the sorting apparatus will now be described. Initially, mineral pieces to be sorted are passed in the direction of the arrow 11 are illustrated in FIGURES 15 by any suitable means such as the conveyor 13. The motor M in FIGURE 5 is started so that the rotary table 28 is rotated at a fairly high speed. The inertia plate 22 will not rotate unless the downwardly projecting portions 23 and 24 encounter oversized pieces of mineral.

As the pieces of mineral are received in the central portion of the table, they will be caused to travel by centrifugal force outwardly through the entrance openings of the various radially extending passages 29. Oversized pieces of mineral will strike the projections 23 and 24 and tend to become wedged or crushed thereby causing partial rotation of the inertia plate 22. The downwardly projecting portions 23 and 24 will thus sweep over the upper surface of the central portion of the rotary structure and as long as any mineral pieces are larger than of a size to pass down the passages, they will engage the inertia plate and be crushed.

The dimensioning of the passages relative to the inertia plate projections is such that the mineral pieces will pass one at a time throughthe various passages out towards the exit openings. As the pieces travel through the passages they become separated from each other as they gain velocity thus allowing the sensing and separation of individual pieces. Normally, the deflecting means such as the door 33 shown in FIGURE 5 remain in their first positions so that the minerals will be thrown to the outer annular receiving chamber 26, as illustrated at the left of FIGURE 5. However, if any one mineral piece has a metallic content, as one example of a given characteristic, exceeding a given amount, in passing the sensing coil 36, there will be developed a signal employed to actuate the solenoid 35 and move the deflecting means such as the means 33 to its second position or partially closed position. As an example, the deflecting means for the passage way on the right side of FIGURE 5 is shown in the partially closed or second position. The mineral providing the actuating signal will then strike the inside sloping surface of the deflecting means and thus be guided or deflected into the inner annular chamber 27 With reference to FIGURES l and 2, it will be noted that the mineral pieces that are not deflected but are received in the annular outer receiving chamber pass through the tubular structure 17 to the container 19 whereas the mineral pieces having a metallic content exceeding a given amount which are deflected to pass into the inner chamber 27 pass to the container 20. The ore or mineral pieces are thus separated into first and second groups depending on the particular given characteristic controlling the sorting.

The manner in which the sensing means determines whether or not a particular piece of mineral has a metallic content greater than a given amount will now be understood by reference to FIGURE 6. In FIGURE 6, the control circuit for each of the sensing means and deflecting means associated with the exit end of each passage designated generally by the numeral 37 is illustrated. Each of these control circuits are identical. Thus, referring first to the upper lefthand corner of FIGURE 6, the sensing coil 36 is schematically shown and constitutes part of a first oscillator A designated generally by the numeral 43. This oscillator will oscillate at a given frequency but this frequency will be varied upon passing of a mineral piece with metallic content close to the sensing coil 36 as a consequence of a changing in the tuning characteristics of the coil 36.

Cooperating with the oscillator 43 is a fixed coil 44 constituting part of a fixed tuned oscillator B designated by the numeral 45. The frequency of the oscillator 45 is fixed at a frequency value corresponding within a given limit to the frequency of the oscillator A in the absence of any metallic bearing mineral. The outputs from the oscillators A and B pass to a mixer 46 and detector 47 which will provide an output signal constituting a function of the beat frequency of the frequencies of oscillator A and oscillator B. This beat frequency will be determined by the frequency difference between the two oscillators, and in the absence of any minerals having any metallic content, this frequency difference will be within the given limit as described.

The output of the detector 47 passes through a coupling condenser C1 to the base of an amplifying transistor Q1. The output from the transistor Q1 is taken from its collector terminal and is in the form of a series of constant amplitude pulses 48, the frequency of which corresponds to the beat frequency. Capacitance C2 is alternately charged and discharged and the resulting current through the diodes D1 and D2 is directly proportional to the beat frequency. The junction point 49 connects to a further capacitor C3 shunted by the diodes D1 and D2, respectively, oriented in opposite directions as shown. This circuit arrangement including resistance R6 results in a given voltage V1 at the junction point 49.

From the junction point 49, the output signal passes through a coupling network R2 and condenser C4 to the base of a second transistor Q2. The output of the second transistor Q2 at a junction point 50 is again taken from the juncture of the collector of the transistor and collector resistance R3 wherein a voltage V2 is developed. The voltage V2 passes through a resistance R4 to the base of a third transistor Q3. The output of this transistor is shown at V3 and is taken from a junction point 51 of the collector resistance R5 and passes to a suitable switch for providing energy to the solenoid 35. When the voltage V3 at the junction point 51 exceeds a given value, the solenoid 35 will be operated.

The circuit is completed by a voltage supply line 52 powered from the power supply line 41 through the slip ring depicted schematically at 39 and regulated power supply 42. This power supply provides B+ power for the transistors as through the collector resistances R1, R3 and R5, the various emitters of the transistors all connecting to ground line 53.

In operation, the number of the pulses 48 per unit time is reflected by the voltage V1 at the junction point 39. Thus, the resistor R6 and associated diodes D1 and D2 all designated generally by the numeral 54 serve to provide a voltage V1 which is proportional to the current flowing through the condenser C2, which is turn is a function of the number of the pulses 48 per unit time. Condensers C3 and C4 and resistance R2 serve to filter the pulses into a fairly even voltage at the base of Q2. This portion of the circuit thus functions generally as a counting circuit and will provide a voltage V1 at the junction point 49 which is a direct function of the number of pulses 48 per unit time.

In the absence of any metallic bearing minerals passing the sensing coil 36, the beat frequency is sufiiciently low that the voltage V1 will hold the transistor Q2 in a partially on condition. As a consequence, the voltage V2 at the junction point 50 will be between the power supply voltage and ground potential and transistor Q3 will be held in a conducting condition so that the voltage V3 at the junction point 51 at the collector of the transistor Q3 will be low as a consequence of voltage drop across R5. In fact, there will be reflected essentially a short circuit so that V3 will be substantially at ground potential and the solenoid will remain unactuated so that the various doors will remain in their first positions.

If now a piece of mineral having a metallic content greater than a given amount passes the sensing coil 36, the oscillator A will become sufficiently detuned with respect to the oscillator B that the beat frequency will increase beyond a given frequency resulting in a number of pulses 48 per unit time greater than that number appearing in the absence of any mineral having a metallic content. The voltage VI at the junction point 49 will thus increase sufliciently to turn on and saturate the transistor Q2 resulting in the voltage V2 at the junction point 50 dropping because of the resistance R3. Dropping of the voltage V2 will then turn off the transistor Q3 as this change in voltage is reflected at the base of the transistor Q3, resulting in the voltage V3 at the junction 51 increasing substantially to the power supply voltage on line 52. When the voltage V3 reaches this value, it will operate a suitable switch to energize the solenoid 35 and thus move the deflecting door 33 to its partially closed or second position and deflect the mineral to the inner chamber 27.

After the mineral piece has passed, the beat frequency resumes its normal lower value so that the solenoid is de-energized and the door immediately opened again by the spring 34 preparatory to the analysis of the next succeeding piece of mineral.

To assure proper operation of the electronic portion of the circuit over long periods of time, there is preferably included an automatic tuning means 55 for the fixed oscillator B. This automatic tuning means essentially detects the voltage V2 at the junction point 50 and will retune the oscillator 45 so as to maintain a fixed frequency difference with respect to the oscillator 43 in the absence of any metallic content bearing mineral pieces.

Thus, with reference to FIGURES 6 and 7, at the referred to fixed frequency difference or beat frequency, Q2 is held in a partially conducting condition as described. The value of R6 is chosen to provide a voltage V1 approximately half way between the saturation and cut-off base voltage for Q2. If the beat frequency changes, V1 changes and this change is amplified by Q2 causing a large change in V2. The voltage V4 in FIGURE 7 gradually follows the changes of V2. The diode D3 has a capacitance which varies with the reverse voltage across it. Thus D3 functions as a voltage variable capacitor and since the frequency of oscillator B depends in part on the value of this variable capacitance, the beat frequency will change when V4 changes.

In operation, as the beat frequency changes and V2 changes, the resulting change in V4 will cause the frequency of oscillator B to shift in such a direction as to cause the beat frequency to return to its original value. Since rapid changes in V2 are not followed by V4, because of R7 and C5, this circut compensates for long drifts without reducing sensitivity.

In order to provide a continuous indication of the operation of the circuits, each circuit includes a tap ofI' lead for the voltage V1 passing through one of the slip rings 39 through a stationary meter 56 to ground. Observation of this meter will thus permit monitoring of the state of the circuit in question.

From the foregoing description, it will be evident that the present invention has provided a novel mineral sorting apparatus. While the sensing portion of the apparatus has been described in conjunction with separating minerals in accordance with their metallic content, it should be understood that any type of sensing means may be employed for operating the deflecting means. In this respect, sensing means may be provided which will generate a signal to operate the solenoid in response to differences in optical characteristics of pieces of minerals such as their color or, for that matter, in response to other physical, electrical, chemical, or optical characteristics.

Further, while the deflecting means has been illustrated as including small solenoid operated doors, other deflecting means might be used such as jets of air operable by the solenoids for small, light pieces of mineral.

The mineral sorting apparatus is therefore not to be thought of as limited to the particular example set forth merely for illustrative purposes.

What is claimed is:

1. A mineral sorting apparatus for dividing pieces of mineral into at least two groups differing from each other in accord with a given amount of metallic content in said pieces of mineral, comprising, in combination: a rotary means including a plurality of radially outwardly extending passage means along which pieces of mineral are caused to travel by centrifugal force when received in the central portion of said rotary means and said rotary means is rotated; deflecting means at the outer end portions of each of said passage means; and electronic sensing means in each of said passage means coupled to actuate associated deflecting means in response to a piece of mineral having said given metallic content passing said sensing means, whereby pieces of mineral having said given metallic content are deflected upon leaving said passage means and thereby separated from the rest of said pieces of mineral.

2. A mineral sorting apparatus for dividing pieces of mineral into at least two groups differing from each other in accord .with a given characteristic, comprising, in combination: a horizontally disposed rotary means mounted for rotation about a vertical axis, said rotary means defining a plurality of horizontal passages having entrance ends adjacent the central portion of said rotary means and exit ends adjacent the periphery of said rotary means such that minerals received in said central portion are caused to travel along said passages by centrifugal force upon rotation of said rotary means; an outer shell structure; an inner shell structure defining with said outer shell structure an outer annular receiving chamber surrounding said rotary means, said inner shell defining one wall of an inner annular receiving chamber having an entrance whose inner wall is defined by said rotary means periphery; deflecting means at the exit ends of each of said passages movable between a first position in which minerals are free to pass from the exit ends of said passages and be received in said outer annular receiving chamber and a second position in which minerals are deflected to pass into said inner annular receiving chamber; and control means including sensing means at the exit ends of each of said passages and responsive to the passing of pieces of mineral having said given characteristic to move said deflecting means from said first to said second position whereby minerals having said given characteristic are received in said inner chamber and all other minerals are received in said outer chamber.

,3. An apparatus according to claim, 2, including an inertial plate means mounted for rotation about said vertical axis in axially spaced relationship to the floor of said passages and central portion of said rotary means and including mineral engaging projecting means terminating a given distance above said floor whereby any minerals of dimensions greater than said given distance are engaged and crushed by said projecting means upon rotation of said rotary means so that only minerals less than a given size pass along said passages.

4. An apparatus according to claim 2, in which said deflecting means for each of said passages includes a solenoid actuated overhead door, hinged along the upper end edge of the exit end of the associated passage for swinging movement from a generally horizontally extending direction defining said first position to a partially closed condition in which the inner side of said door defines a downwardly sloping deflecting surface defining said second position.

5. An apparatus according to claim 4, in which each deflecting means and control means for actuating its associated door are carried by said rotary means; a vertical shaft mounting said rotary means; a motor for driving said shaft; and slip ring means carried by said shaft for passing electrical energy to each control means.

6. An apparatus acording to claim 2, in which said given characteristic constitutes a metallic content in said mineral, said control means comprising a first oscillator having an oscillating coil constituting said sensing means, passing of a piece of mineral having a metallic content changing the frequency of oscillation of said coil; a second oscillator having a frequency corresponding within a given limit to the frequency of said first oscillator in the absence of any mineral having a metallic content; mixer, detector, and amplifying means connected to said first and second oscillators for providing a beat frequency signal arising from the difference in the frequencies of oscillation of said first and second oscillators; and means responsive to said beat frequency signal for actuating said deflecting means when the frequency of said beat frequency signal exceeds a given frequency.

7. An apparatus according to claim 6, including automatic tuning means responsive to said beat frequency signal for maintaining the frequency of oscillation of said second oscillator within said given limit of the frequency of said first oscillator in the absence of any minerals havinga metallic content passing by said oscillating coil.

References Cited UNITED STATES PATENTS 653,792 7/ 1900' Dasconaguerre 209-420 1,358,375 11/1920 Koch 209120 X 2,045,769 6/ 1936 Geficken 20 911.8- X

3,117,080 1/ 1964 Krestin 209-1 3,283,899 11/1966 Vedvik 2091 X FOREIGN PATENTS 929,046 6/ 1955 Germany.

FRANK W. LUTTER, Primary Examiner.

US. Cl. X.R.

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