US2688437A - Centrifugal separator - Google Patents

Description

p 1954 G. HJJ. MONNET CENTRIFUGAL SEPARATOR Filed Nov. so, 1948 2 Sheets-Sheet l GEORGES Harm JOSEPH MONNET ATTOR N EY Sept. 7, 1954 H. .1. MONNET CENTRIFUGAL SEPARATOR 2 Sheets-Sheet 2 Filed NOV. 30, 1948 on FM GEORGES HENRIJOSEPH MONNET ATTO R N EY Patented Sept. 7, 1954 CENTRIFUGAL SEPARATOR Georges Henri Joseph Monnet, Moirans, France, assignor to Societe Anonym'e des Manufactures des Glaces & Produits Chimiques de Saint- Gobain, Chauny & Cirey, Paris, France Application November. 30, 1948, Serial-No. 62,677'

Claims priority, application France December 4; 1947' 2 Claims.

The present invention concerns a. method and.

means for sorting abrasive grains, i. e. separating them into different sizes in view of their use for surfacing glass, marble or similar substances.

That sorting is commonly made by'levigation under the effect of gravity. The abrasive grains are suspended in water flowing through a channel, by example a horizontal channel; they are carried on by the water whilst they are sinking by gravity. As theirv sinking. velocityrapidly decreasesaccording to their size, they settle in the channel the farther from the inlet as they are finer and consequently, they can be separately gathered. But the relatively weak force of gravity which causes the sinking of the grains involves cumbersome apparatus for treating important quantities of fine materials.

This invention has for its object to substitute to the weak and limited force of gravity'the more.

powerful and less limited force of centrifugal action whereby the. settlement is speeded in time and space because the velocity by which. the grains. move in the liquid is proportional to the centrifugal force.

Inorder to perform the. invention, there is provided a rotating container through which the liquidcarrying the grains is passed from one end to the'other end of the container substantially parallelly to the axis while beingrotated. by the container.

orifices through which pass the grams settled in the apparatus. The flowing of the liquid between the inlet and the outlet is determined by guiding surfaces conditioned only for assuring the liquid to be rotated by the apparatus and for presenting inclined surfaces to the perpendiculars to the axis of rotation in order to receive the grains moved away from the axis by the centrifugal force.

The velocity of rotation, as well as the rates of ingress and egress of the liquid and of its extrusion with the sorted grains are maintained fixed to any value which is determined in order to obtain the desired sorting.

The coarsest grains settle near the inlet and the finest near the outlet, as the deposit of the grains is produced along the apparatus according to their dimensions.

Theyare extruded through peripheral orifices of the container communicating with the outside. If these orifices are always open, the extruding is continuous, it is discontinuous if the orifices are opened at separated intervals. The grains ejected from the diiferent extruding openings Suchv container is closed except at v the. inlet andoutlet openings for the liquid and at 2. may be separately collected to obtain grains of decreasing sizes.

The liquid whichpassesthrough the apparatus can be divided into several distinct streams, each of which being separately centrifugated in order to obtain; a particular sorting in each stream respectively. Care must. be taken to avoid that grains sorted by the different streams shall not be mixedlwith another stream or with the grains of. different sizes deposited by another stream.

The container'm'ay be surrounded by a closed envelop in which. a determined pressure may be maintained in order to counterbalance the effects of the inner pressure due to centrifugal force inside the rotating container.

The process according to the invention may be carried out by means of a single centrifugal alpparatus provided with one or several extraction orifices, or by means of several centrifugal apparatus having diflerent characteristics, each apparatus being fed byliquid issued from another apparatus retaining coarser grains than those it retains itself.

As the centrifugal acceleration may be much higher than that of gravity, the latter becomes comparatively negligible and the rotation axis of the apparatus may-be orientated in any direction.

Referring to the accompanying drawings, in which-corresponding parts are designated by correspondingmarks of reference- Figure 1 represents in longitudinal section an apparatus suitable forv carrying out my invention, and

Figure 2 is across section thereof.

Figures 3 to 11 represent modifications of the structure shown in Figure 1.

As shown in Figures 1 to 5, the centrifuge i is of ageneral cylindrical form fast on the horizontal axes: la, lb which are-hollow and through which'the water carrying the grains to be classified (hereinafter called liquid) is fed and removed, suitable valves A, B (see Figure 1) being locatedif desired,.in the axes to control the rate of ingress and egress.

The peripheral Walls of the centrifuge are as shownin Figures 1 to 6 and in Figures 10 and 11, provided with one-or more. annular channels 5 formed by annular walls inclined to the axis of the centrifuge, orifices 5 being provided in the walls of the centrifuge at the bases of the channels. Within the centrifuge is located a filler t, forming with the walls of the centrifuge an annular space 3, connected with the walls of the centrifuge by the longitudinal partitions ii. The liquid entering at la flows outwardly and passes along the annular space 3. The grains to be separated are thrown by centrifugal force outwardly and are deposited in th channels from which they are extruded together withsome of the water through the orifices 5.

In Figure 3 I have shown means for separately collecting grains of different degrees of fineness, such means consisting of collecting chambers 8 and 9 surrounding the centrifuge, the one receiving the flow from the orifice in one channel and the other from several channels, each discharging through the parts and I I.

In the arrangement shown in Figure 4 the grains ejected from the orifices of all of the several channels are collected in a single non-rotating chamber 12 carried on the axes Ia, lb by the stuffing boxes l3, the grains being removed from the chamber through the outlet M.

In Figure 5 two concentric centrifuges l5 and I6 are shown, each having the channels or orifices before discussed. The orifices in the inner centrifuge discharge through the tips 20. This arrangement provides two annular spaces I1 and I8 between which the liquid divides on entering the centrifuge.

In Figure 6 the centrifuge of substantially the shape shown in Figure 1 is mounted on the upper end of the vertical shaft 22 and is fed through the pipe 24 which carries the filler at its lower end. The liquid is delivered from the pipe to the bottom of the centrifuge and arises around the filler being discharged through the outlet 25.

The figures of the drawings before discussed involve centrifuges of generally annular shape;

but it is within the scope of this invention to form the centrifuge of the two cones 28 and 29 united at their base (Figure 7) or by a single right cone 30 (Figure 8) or by a single cone 3| whose bottom is recessed and which is provided with a separator 32 (Figure 9) or, if preferred, the centrifuge may be pear-shaped enclosing a filler 33 of the corresponding shape (Figure Obviously different peripheral velocities will exist at the different channels resulting in a classification of the grains separated thereby.

Figure 11 represents a form of collector that may be applied to any of the preceding forms. In this figure, 36 represents hollow elastic tubes surrounding the centrifuge at the zones in which are located the exit orifices, the tubes being held in place by annular rings 31 fast to the centrifuge. An air tube 38 is connected with the tubes 36. When the latter are inflated they seal the orifices. When deflated the orifices are uncovered and the escape of liquid with entrapped grains is permitted from the channels.

It will be seen that the character of separation effected in a centrifuge, such as before described. will vary with the angular velocity of the centrifuge and its diameter, and that by passing the liquid successively through a plurality of centrifuges varying in diameter and speed of rotation, (1. e., having different peripheral speeds) grains of different sizes may be separated from each other.

In most of the above embodiments the liquid is guided by the undulated surface of the centrifuge and by partitions such as the radial partitions E in Fig. 2. The guiding surfaces being only purposed for presenting surfaces which are inclined in respect to the perpendicular to the rotation axis and for ensuring the rotation of the liquid, they may be arranged in numerous different ways.

In particular the radial partitions 6 of Fig. 2 can be helicoidal, their generating lines may be perpendicular to the rotation axis or inclined in respect to said axis.

Having thus described my invention, what I claim is:

1. In an apparatus for separating abrasive grains carried in suspension in a liquid, a centrifuge comprising a bowl made of a succession of annular walls inclined to the axis of the centrifuge and forming juxtaposed annular channels in communication with the inside of the bowl and provided at their bases with outlets for the extrusion of a part of the liquid and of certain of the grains suspended therein, a filler within the bowl and coaxial thereto, an inlet at one end of the centrifuge and an outlet at the other end for the passage of the liquid and the grains carried by it through the centrifuge, in combination with a series of annular elastic inflatable tubes, each tube surrounding the base of one annular channel and held at a close proximity of the outlet openings of said channel by an annular ring fastened to the bowl, and means for inflating the tubes against the said outlet openings.

2. In an apparatus for separating and classifying abrasive grains carried in suspension in a liquid, a centrifuge comprising a bowl made of a succession of annular walls inclined to the axis of the centrifuge and forming juxtaposed annular channels in communication with the inside of the bowl and provided at their bases with outlets for the extrusion of a part of the liquid and of certain of the grains suspended therein, a filler within the bowl and coaxial thereto, an inlet at one end of the centrifuge and an outlet at the other end for the passage of the liquid and the grains carried by it through the centrifuge, in combination with a series of annular elastic infiatable tubes, each tube surrounding the base of one annular channel and held at a close proximity of the outlet openings of said channel by an annular ring fastened to the bowl, and means for inflating the tubes against the said outlet openmgs.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 508,270 Bell Nov. 7, 1893 622,712 Rissmuller Apr. 11, 1899 669,732 Ohlsonn Mar. 12, 1901 927,059 Kuchs July 6, 1909 1,014,849 Richardson Jan. 16, 1912 1,101,548 Hoffman June 30, 1914 FOREIGN PATENTS Number Country 'Date 870,450 France Mar. 11, 1942

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