US2172299A - Apparatus for automatically regulating the evacuation of heavy products - Google Patents

Description

Sept. 5, 1939. sp 2,172,299

APPARATUS FOR AUTOMATICALLY REGULATING THE EVACUATION OF HEAVY PRODUCTS Filed April 2, 1937 2 Sheets-Sheet l as 29 g I w .17 20 16 q 9 J :/A4 w q i :f 1

Sept. 5, 1939.

D. SPINETTA 2,172,299

APPARATUS FOR AUTOMATICALLY REGULATING THE EVACUATION HEAVY PRODUCTS 2 Sheets-Sheet 2 Filed April 2, 1937 8 7 Mm 4 W 1. a M a .g wwj u o KW 7 My 3 mvfl o .s t w a z a a a y h w //VVE/Y7'0R JoMw/ ue Sp/WETM Patented Sept. 5, 1939 UNITED STATES APPARATUS FOR AUTOMATICALLY REGU- LATING PRODUCTS THE EVACUATION OF HEAVY Dominique Spinetta, Nogent-sur-Marne, Seine, France, assignor to Preparation Industrielle des Combustibles, Nogent-sur-Marne, Seine, France Application April 2, 1937, Serial No. 134,666- In France April 10, 1936 3 Claims.

The present invention relates to apparatus for use in sieves for washing granular material such as coal or other minerals, and permitting of the automatic regulation of the evacuation of heavy products from nil to the maximum permitted by the sieves.

A device for automatically regulating the evacuation of the schist in a sieve-jig for coal and the like is known, in which a float (not in contact with the bed of material to be separated) acts on a counter-pressure air cock to open this cock more or less in accordance as the amplitude oi the movement of the float, that is to say in accordance with the thickness of the bed of schists. This action of the float on the cock takes place intermittently under the influence of the jigging movements produced by water pulsations as illustrated in the U. S. Patent to Wolf No. 1,666,189, dated April 17, 1928, and is opposed to the continuous action of any suitable mechanical control device which, through the medium of a friction transmission, tends constantly to bring the cock into its closed position.

In this known device, the evacuation of the schist takes place above a sill having a fixed position, and the evacuation of the schist depends on the degree of opening of the cock which allows the air in the zone situated above the liquid to escape more or less rapidly and consequently to create a counter-pressure which is more or less opposed to the action of the water beneath the bank of schist in the evacuation zone. 7

With this device, the regulation effected b the counter-pressure air cock was only perfect when the variation of the mixture 'ofcoal and schist (or the light product and the heavy product) did not exceed a certain mean. If, however, the mixture contains very little of one of the two components, the evacuation above the sill would not reach a desirable maximum or could not be rendered nil.

It has also been proposed in connection with automatic regulation of the evacuation of the schist in sieve-jig washers to use an oscillating blade placed beneath the grid which supports the beds of products to be separated beneath the zone of evacuation, the said blade being connected to the float by means of a transmission device similar to that previously described. With this arrangement, a suitable control device acts on the blade tending continuously to bring it into, or maintain it in such position that it offers maximum resistance to the water in movement which tends to force the schist over the evacuation sill in such manner that the quantity of schist evacuated at each jigging stroke is a minimum. The vertical displacements of the float tend to bring the oscillating blade towards a position where it offers least resistance to the action of the water'beneath the evacuation sill. This obstruction, which is more pronounced as the displacements of the float become smaller, cannot, however, become total as would be desirable if the bed of schist became of insufficient depth, or if it were replaced by a pure coal. It would then be impossible to prevent certain part of this coal from being evacuated and distributed in the zone reserved for the schist. In addition, this device has not, in the case of medium displacements of the float, a sensitiveness and tendency to yield as exist in a device in which an air cock is employed.

Finally, it is impossible with this known device to oscillate the blade to obtain sufficient evacuation when the bed of schist reaches a very great depth. From what has previously been said. it will be understood that the employment of one or other of the devices mentioned have their drawbacks.

The present invention relates to a device by which these drawbacks are eliminated.

The device is essentially characterised by the fact that if the depth of the bed of schist varies relatively slightly from the'medium depth, an air cock only is employed. On the contrary, in every case the blade or equivalent device only comes into action when the depth of the bed of schist becomes very small or even when all the schist is escaped, or, on the other hand, attains a certain maximum.

This arrangement has the advantage that automatic regulation of the evacuation is effected, under desirable conditions of sensitiveness and flexibility when the modifications of the depth of the bed of schist are relatively small, that is to say when the proportions of the mixtureof the products supplied to the installation vary slightly, whilst the adjustment is strongly reinforced by the use of the blade or of a sliding sill when the variations of feed become substantial, for example if the washer is fed solely with coal or, on the contrary, solely with schist, in cases in which the limits of adjustment by the air cock are insuflicient. I

The evacuation takes place on a scale initially adjusted for medium variations in the depth of the bed of schist, and the blade or sliding sill becomes operative only when the depth becomes very small or even when allthe schist is escaped, or on the contrary exceeds a certain limit.

The arrangements employed are shown diagrammatically by way of example in the attached drawings, in which- Figs. 1 and 2 show two forms of construction.

In Fig. 1 the coarse coal introduced into the washer box I is, under the influence of water pulsations, divided above a grid 2 into schist3 and washed coal 4 which move towards their respective outlets; and schist is evacuated between two dampers 1 and 8 arranged in such manner that the schist forming a bank cannot flow by gravity.

The automatic adjustment element is formed by a blade or bafile 9 movable about an axis ID. The schist can be evacuated between the two dampers I and 8 by a thrust of the water; this thrust is, between points II and I2 of the grid 2, a function of the position of the blade 9; when this blade is in the position I3, the water passes freely between the points II and I2 and the quantity of schist evacuated is the maximum; when the blade 9 is in the position I4, the passage of the water is nil in the zone comprised between the points II and I2 and evacuation of the schist is also nil.

To effect automatic evacuation, it is only necessary to connect the blade 9 to a device which actson it as a function of the depth of the layer 3 of schist situated on the washing grid 2; for this purpose a float I5 is arranged in a vertical tube It which traverses the washing bed and the grid, and follows freely the pulsations of the liquid in which it is immersed; its functioning is absolutely certain, as it is integral with a rod I5a. guided by two bearings I1 and I8 located outside the water. An air cock I9 of any form is mounted above the compression chamber 20. On the rod I50; of the float are provided devices which, when the movement of the float is small, that is to say when the high points attained by the float are below the central position, the cock closes; on the other hand, when the movement of the float I5 increases, that is to say when the high points reached by the float are'above the central position, the cock opens. Finally, when the high points reached by the float I5 are in the neighbourhood of the central-position, the blade 9,

which is beneath the outlet orifice of the schist, is maintained in the central position shown in full lines in Fig. 1, this being due to the action of a counter-weight 2I acting through the medium of a toothed wheel 22 pivotally mounted on the axis 23, of a toothed pinion 24 mounted on the axis 25, of a two-armed lever 26 and of a rod 21 on a lever 35 connected to the blade 9.

When the bed of schist has a medium depth,

that is to say when the boundary between the schist and the coal takes place through the medium of the damper 8 at unequal distance from the points 8 and 8a, the float I5 is in a medium position which, through the previously mentioned elements, brings the cock I9 in the half-open position. At this moment the counterweight 2I alone acts on the blade which is in the central position 9 shown in full lines in Fig. 1. If the depth of the bed of schist 3 increases, the water driven back by the piston encounters increased difliculty in passing across the washing bed, and the upward movement of the float I5 increases which causes progressive opening ofthe cock I9; the Water forced back by the piston under the washing bed then passes in its greatest quantity into the chamber 20, the air which under the infiuence of this piston action is caused to penetrate into this. chamber and then to leave it, no longer being controlled by the cock I9; at this instant the evacuation of the schist increases between the dampers I and 8, which tends to cause diminution in the depth of the bed of schist 3.

If, on the other hand, the bed of schist tends to fall the opposite effect is produced; the height of the float I5 diminishes, the cock I9 is closed, the circulation of air between the compression chamber 20 and the atmosphere is obstructed, the flow of water, as shown by the arrow G, towards the chamber 20 is reduced, and the evacuation of the schist decreases, which tends to restore the thickness of the bed of schist to its most favorable amount.

The apparatus thus functions when the mean variations of the composition or output of the products fed into the sieve are produced. If at a given moment a large feeding of schist takes place, the bed 3 increases rapidly in depth, the movement of the float I5 becomes a maximum, the cock I9 opens to its full extent and after having passed a predetermined angle of opening acts on an electric contact which causes current to flow into an electromagnet 28; the latter causes the lever 26 to turn in the direction of the arrow F, which, through the medium of a rod 21 and a lever 35, brings the blade into the position I3; owing to this the force of the pulsation between the points II and I2 is increased, and the quantity of schist evacuated between the dampers I and 8 becomes a maximum. If, on the other hand, the flow of schist or the feed to the sieve ceases completely, the opposite effect is produced; the movement of the float becomes a minimum one, the cock I9 is then completely closed, and at this moment actuates a second electric contact which causes current to pass into the electromagnet 29; the lever 26' turns in the direction of the arrow F, which brings the counter-weight 2I in the position 33 and the blade 9 into the position I4; the pulsations between the points II and I2 become very weak and evacuation of the schist between the dampers I and 8 'is substantially nil.

The apparatus may be arranged in the manner shown in Fig. 2, this providing maximum eniciency for the automatic regulation; in this case the movable regulating element is formed by a damper which is capable of sliding vertically in accordance with the displacement imparted by the lever 26 to the rod 27 attached to the upper end of the damper 30.

The apparatus then functions in a similar manner to that previously described; when the float I5 is displaced to a central position,'the air cock I9 serves to regulate the evacuation of the schist 3 between the lower end of the damper 8 and the upper extremity of the damper 30. When 'a sur plus of schist reaches the sieve I the cock I9,

which is fully open, causes'current to flow into the servo-motor 28 which, by causing the lever 26 to pivot in the direction of the arrow F, causes downward displacement of the rod 21 with consequent downward movement of thedamper 30, so that the upper edge of the latter is brought into the position 32; the evacuation of the schist is then a maximum. As soon as the depth of the bed of schist has been sufficiently reduced, the movement of the float I5 decreases, the cock I9 tends to close and no longer acts on the servomotor 28, and the counter-weight 2| which is in the position 33 returns to its position 2| bringing the damper 30 to its central position through the medium of the elements 22, 24, 26 and 21.

If the feeding of the schist or even the feeding of the sieve stops completely, the depth of the bed of schist decreases, the cock I9 is closed and acts, through the medium of the servo-motor 29, the lever 26 and the rod 21, on the damper 30 so as to lead the latter to its upper position 34, thus completely interrupting the evacuation of the schist; at this moment the counter-weight 2| is in the position 33 and the sieve can wait, without risk of loss of coal in the schist, until the feed of the latter becomes normal.

The connection between the float and the air cock I9 and between the air cock [9 and the device controlling the solenoids 28 and 29 is similar to that described in the U. S. Patent No. 1,666,189 to Philippe Wolf. This device consists essentially of a shaft 36 continuously rotated in one direction by motor driven chain and sprocket means 31, 38 acting through the medium of a worm 39, a helical wheel 40, and a friction clutch 4|. The shaft 36 is intermittently rotated in the opposite direction by engagement of the stop 42 on the rod l5a of the float with a dog 43 secured to one of the strands of an endless chain passing over suitable wheels, one of which 44 is secured to the shaft 36. The said shaft 36 actuates a commutator 45, 45a for example through the medium of gears 46, 41, the latter one of which controls the air cock I9. If the latter is not in use, by means of the devices provided, a finger 48 of the commutator will cause a current from any electric source (for example 49) to flow into the solenoid 28, or the solenoid 29 according as the displacements of the float are a maximum or minimum. If the air cock I9 is employed, as shown on the drawings, it will be completely open when the solenoid 2B is energized (maximum elongation) but will be entirely closed when current is caused to flow into the solenoid 29 (minimum elongation) When the displacements of the float are of medium amplitude, the contact finger 48 will oscillate through an angle 50 without reaching either of the contact studs.

Evacuation will then be regulated entirely by the extent of opening of the cock l9. If this cock is not used, the evacuation will be subjected to regulation in accordance with maximum and minimum displacement of the float.

If the displacements are a minimum, the stop 42 will not reach the block 43, and owing to continuous friction, provided in the devices 39, 49, 4| the finger 48 is held against the contact 45 of the solenoid 29 until, by reason of the cessation of the evacuation, the bed of schist becomes deeper, thus causing larger strokes of the fioat.

What I claim is:

1. In an apparatus for washing and separating mixed materials of different densities by Water pulsations, said apparatus being of the type comprising a washer-box to contain the water, a grid to support the materials in position to have pulsated water pass upwardly therethrough, a sill over which the schist is evacuated, an air pressure chamber into which the schist discharges, a float movable responsive to pulsations of the water, a schist evacuating control member in the form of a counter-pressure air-cock for regulating the air pressure in said pressure chamber, and a connection between the float and said air-cock whereby said float controls said air-cock to regulate the average evacuation of the schist; the combination with said air cock, of means controlled thereby for controlling the evacuation of the schist above and below the plane of average evacuation, said means comprising a second schist evacuation control member, and a connection between said air-cock and said second control member whereby the latter is actuated only when the air cock reaches substantially its fully open and fully closed positions.

2. The apparatus as set forth in claim 9 in which the second schist evacuation control member comprises a pivoted blade located beneath the evacuation sill to regulate flow of water through the grid and the materials supported thereon.

3. The apparatus as set forth in claim 9 in which the second schist evacuation control member comprises a vertically slidable sill plate.

DOMINIQUE SPINETTA.

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