US2870912A - Apparatus to separate the solid particles in a liquid solution and to dry said particles - Google Patents

Description

THE SOLID PARTICLES IN TO DRY SAID PARTICLES 2 Sheets-Sheet l INVEHTOR FRANQIS JOSEPH HENRI MATf/IEU BY mm ATTORNEYS F. J. H. MAT-HIEU 2,870,912 SEPARATET ID PARTICLES IN SAID PARTICLES Jan. 27, 1959 APPARATUS TO HE SOL A LIQUID SOLUTION AND TO DRY Filed Aug. 11, 1955 2 Sheets-Sheet 2 x INVENTOR Fmlvgos JOSEPH HENRI MATH/EU BY main miw. ATTORNEYS APPARATUS T0. SEPARATE THE PARTI- CLES IN A LIQUID SOLUTION AND TO DRY SAID PARTICLES 1 Frangois Joseph Henri Mathieu, Saint-Cloud, France, as-

Slgl101 to Societe les Construction Guinard, Courbevoie,

. France, a corporation of France Application August 11, 1955, Serial No. 527,742

Claims priority, applicationFrance August 11, 1954 2 claims. (Cl. 210-413 The present invention aims at providing a machine to separate the solid particles, such as, for instance, crystals from a liquid solution and to dry these particles in a machine of the type in which the separation as well as the drying of the solid particles are carried out between a rotating cone provided with scraping members and a truncated perforated basket concentric to the cone provided with scrapers and rotating in the same direction but at a diiferent speed. In such machines in which the cone provided with scrapers and the perforated basket are housed in a casing provided at the top with an axial inlet for the matter to be separated and dried and with a sideoutlet Patented Jan. 27, 1959 tion from the entraining liquid phase, in the zone in which at its base, the separation of the solidparticles and their drying after the separation are carried out through the centrifugal force imparted to the particles as they are dragged along by thescrapers which are constituted by helical ribs on the conical element.

The use of such machines in various industries such as the sugar industry, althoughallowing to obtain a rather high efficiency in the separation of the crystals of sugar from the molasses, ofiersnevertheless the drawback of the crystals separating from the liquid in which they were in suspension and dried, have not the faultless aspect required for the trade, because each crystal-is coated, after the separation from the liquid phase, with. a thin film of this liquid which cannot always be thoroughly removed by drawing. The same drawback of the separated particles being coated with an undesirable film of the liquid phase mayalso occur in other industries, for instance in the textile industry. In this industry suspensions often occur in which the liquid phase is a liquid noxious to the, operatingv personnel, such liquids being, for instance, acids. In this case, the fibres constituting the solid particles, after having been separated from the liquid phase of the uspension, an acid for instance, are each lcoatedwith a thin. and adherent film which necessarily must be more or less fully removed. Most generally the solid particles, separated fromthe liquid phase and dried afterwards in separating machines of the type described must subse: quently be submitted to a washing step outside the aforesaid machine, which makes the finished product more expensive.

Ithas been proposed in the art to carry out the separation. of the solid particles and their drying in. a single centrifugal dryer of the type above mentioned, but, in the known machines, the washing is carried out under conditions which do not permit to obtain solid particles having a faultless aspect and qualities satisfactory enough, either-for using these particles directly if they constitute asemi-finished product, or placing them on the market if they'constitute a finished product. a The object of the present invention is to provide a process and apparatus allowing to avoid the above mentioned drawbacksand to obtain solid particles of a faultless aspect and directly usable as intermediary products .astwcll as for sale as a finished product. p a The process according to the invention consists inwiththe washing is carried out, from the positive action of separating elements of the machine impelling the particles, i. e., for'instance, the scrapers. As the solid particles are no longer dragged along by the scrapers in the direction of the discharge outlet, they accumulate in this washing zone, forming a strand of material subjected to the action of the washing liquid, an action which is prolonged since the strand of material is advanced, very slowly due to the arrival in this zone of new solid particles. Preferably this washing zone is located intermediate the discharge outlet of the machine for the solid particlesand the end of the zone in which the separation of the solid and liquid phases is eifected in the machine.

According to a preferred embodiment of the apparatus provided for carrying into effect this process, the machine of the above mentioned type is provided with scrapers,

parts of which havebeen cut away intermediate their ends to form. a gap in each of the scrapers, all of which gaps are located preferably atthe same level, the washing water being introduced in the machine through an axial inlet and flowing through these gaps. The water enters through bores provided in the wall of the scraping cone, at the level of these gaps. In order to obtain a uniform washing of the strand of solid particles, such as for instance the above-mentioned crystals, the edges of the scrapers along the lower end of the gaps, which edges are located at the same level, support a baffie plate having preferably the shape of a conical ring suitably sloped toward the rotary axis of the machine so that the washing water, passing through the bores and flowing against this ring is distributed along the edge of this ring in a uniform tion 1 which has anupper cylindrical bore B communidrawing thesolid particles when completing their separa sheet passing through the strand of particles passing along the above-mentioned truncated basket facing the gaps in the scrapers.

According to another important feature of the present invention, the drying step of the washed solid particles is further improved by providing a second row of recesses below the aforesaid gaps in the scrapers, so as to withdraw the washed particles at least temporarily from the centrifugal action of these scrapers and allow them to fall down slower towards the discharge outlet of the machine, as these solid particles are no longer submitted to the positive action of the scrapers in the zone of thesesecond recesses.

By way of example, a form of embodiment of the invention is described hereafter and illustrated in the annexed drawing.

Figure 1 illustrates an axial half section of a machine according to the invention.

Figure 2 illustrates diagrammatically in elevation the vertical fingers4 which enter holes 5 provided in the wall of the head portion 1. The frusto-conical element 3 has, in its top wall 40, near the inner face of its side-wall, apertures 39, and it is provided, on the outer face of its side wall, with helical scrapers 3' integral therewith.

Apertures 1A are provided in the wall of the head porcating with said apertures.-

Basket 2 is fixed, by means of bolts 6, on a ring-shaped element 7 which is the driving element of said basket, inclined apertures 8 being provided in the ring-shaped element 7. The basket 2 is coated internally with a sifter 9 maintained in place by tightening its lower end 10 between the lower ring 11 of the basket and a tightening ring12 fixed thereto by screws 13, and by tightening its upperend 14 between the upper ring 15 of the basket and an upper tightening ring 16 fixed thereto by means of screws or bolts 17. The basket 2 is surrounded by a frusto-conical stationary wall 18 determining therewith a chamber 19. The wall 19 is in its turn surrounded by a second frusto-conical wall Ztlfixed by means of bolts 21 to a stationary head 22 having a centrally disposed hub 23 engaged in the cylindrical bore B. The stationary head 22 carries, by means of bolts 24, a disc 25 freely engaged by its central aperture 26 on the upper part 27 of the conical element 1. it further carries a tube 28 through which washing liquid, preferably water, is introduced in the machine, the said tube having a vertical portion 29 passing through the hub portion 23 and through an axially bored bolt 30 screwed in the top wall of the conical element 1. 31 denotes a deflector soldered at 33 on the tube 29.

According to the present invention, several apertures 31 are provided in the Wall of the frusto-conical element 3 and they are traversed by the washing water which flows towards the outer surface of the frusto-conical element 3 where it washes the particles situated at this level and separated from the mother liquor in the zone above these bores. To improve this washing effect and to increase the efficiency of the operation, a large gap 35 is provided in each scraper 3' at the level of the bore 31. As is shown particularly in Figure 2, a conical ring or bafile ring 36 rests upon the edges of the scrapers formed along the lower ends of the gaps 35, the slope of this bafile plate in relation to the axis being preferably such that the water flow through the bores 31 is pored in an uniform sheet from the free edge of the baflle plate, in recess from the edge of the gap,

For preventing the washing liquid to flow into the lower part of the machine, an annular baffle 32 is soldered at 33 to the frusto-conical element 3.

The device functions as follows:

The suspension of solid particles in a liquid is introduced into the machine through the nozzle 34 and flows through the hub portion 23 of the stationary head 22, in the direction of the arrow F, between the cone l-3 provided with scrapers 3 and the perforated basket 2. The centrifugal forces act to separate the solid particles from the liquid which passes through the openings in the basket 2, in the direction of the arrow F1 to be discharged from the machine. The particles which are thus separated from the mother liquor are submitted to the action of the scrapers and, due to their helical shape, these scrapers drag along the particles in moving them downwardly and in the direction of rotation of the scraper-bearing cone, provision being made for the shape of these scrapers, being indicated by the arrow F2 in Fig. 2. In the zone of the gaps 35, the scrapers do not act any longer directly on the particles which, through the action of the centrifugal forces, are flattened, as shown diagrammatically in 37 (Figure 1) against the sifter which drags them along. ln this zone, a strand or a continuous ring of particles is formed as the particles are, on the one hand, driven in rotation by the basket and pushed downwardly by the unceasing arrival of new material, while, on the other hand, they are no longer positively dragged downwardly by the scrapers, so that their movements towards the apertures S and the discharge space 38 are strongly reduced. The washing of the particles or crystals takes place in this zone, by means of the washing liquid introduced in the machine through the bent pipe 2829. The washing liquid enters the conical head and, through the apertures 39, it passes into the frusto-conical element 3; it flows out through the apertures 31, and due to the baifle-plate 36 it forms a sheet of water which acts on the strand of particles formed at 37 in the zone of the gaps 35 in which the descending speed of the continuous strand of particles is small. The washing eflfect of the washing liquid is powerful enough to remove from the particles the film of mother liquid in which they are embedded, or to reduce strongly the concentration of this film.

To improve the drying of the washed particles during their further descent towards the discharge space38, the particles or crystals have to pass through a second zone of recesses provided in the scrapers. These recesses 39 are also all at the same level and, in the zone of the scrapers corresponding to these recesses, the particles are anew withdrawn from the positive downward dragging effect of the scrapers and flattened against the basket which drives them in rotation. Since the descending speed of the particles in this zone is thereby decreased, the time during which they are submitted to theaction of the centrifugal forces is increased and thereby also their degree of dryness before they are again dragged downwardly by the scrapers towards the discharge space 38 of the machine.

What I claim is: t I

1. Apparatus to separate the solid particles from a liquid suspension including a cone adapted to be rotated round its axis and provided on its outer surface with helical scrapers, a truncated basket surrounding said cone, forming with said cone a passage chamber in which are disposed the scrapers and adapted to be rotated in'the same direction as the cone but at a ditferent speed, means to introduce in said chamber a suspension of solid particles in a liquid, means to discharge in separate zones, on the one hand the liquid of the suspension and on the other hand the solid particles, apertures provided in the cone in the zone corresponding to the discharge of the crystals, means provided in the axis of the cone to introduce in said cone a washing liquid passing through said apertures into said chamber, and gaps provided in the scrapers at the level of the apertures and extending substantially in the direction of the aforesaid cone axis whereby the solid particles are withdrawn from the action of the scrapers and undergo a prolonged washing.

2.'Apparatus to separate the solid particles from a liquid suspension including a cone adapted to be rotated round its axis and provided on its outer surface with helical scrapers, a truncated basket surrounding said cone, forming with said cone a passage chamber in which are disposed the scrapers and adapted to be rotated in the same direction as the cone but at a different speed, means to introduce in said chamber a suspension of solidparticles in a liquid, 21 zone being established in said chamber for the separation of said solid particles from said liquid, means to discharge in separate zones, on the one hand the liquid of the suspension and onthe other hand the solid particles, apertures provided in the cone in a zone intermediate said zone of separation and the discharge zone of the solid particles, means provided in the axis of the cone to introduce in said cone a washing liquid passing through said apertures into said chamber and gaps provided in the scrapers at the level of the apertures and extending substantially in the direction of the aforesaid cone axis whereby the solid particles are Withdrawn from the action of the scrapers and undergo a prolonged washing; theedges of the scrapers along the lower ends of the gaps being slanting towards the top and towards the basket and supporting a ring, the radial width of which is smaller than the part of the scrapers on which it rests, whereby said ring forms a baffle transforming the jets of the washing liquid gushing through the apertures into a continuous sheet passing through the chamber in the direction of the basket.

References Cited in the file of this patent UNITED STATES PATENTS

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