US2808201A - Centrifugal machine for separating and clarifying liquids - Google Patents

Description

Oct. 1, 1 5 J. M. MAY E UX 2,808,201

CENTRIFUGAL MACHINE FOR SEPARATING AND CLARIFYING LIQUIDS Filed July 14, 1954 2 Sheets-Sheet 1 \NVENTOR 0 SAN MAURICE MAYEUX ATTO R N EYS CENTRIFUGAL MACHINE FOR SEPARATING AND CLARIFYING LIQUIDS Jean Maurice Mayeux, Algiers, Algeria Application July 14, 1954, Serial No. 443,401 Claims priority, application France September 25, 1953 11 Claims. (Cl. 233-28) nated, whether solid or liquid, before they may rest on a rigid surface.

Those partitions, commonly called discs or dishes are conical in shape.

To justify the generalized use of this sort of partition, constructors use, as a base, measurements of the falling speed of solid particles, in static decantation, wherein the time of decantation is effectively a direct function of the length of the paths followed by the products which are being decanted before they reach the bottom of the'vats.

The fact that, for a given liquid and a bowl having a given volume, the results of the centrifugal clarification or of the centrifugal separation of two or more liquids, are improved when the number of discs is increased was formerly thought to confirm validity of the analogy which was believed'to exist between the static and the centrifugal decantation. An improvement of the results, consequently, was sought in increasing the volume and speed of the bowls, on the one hand, and, on the other hand, in

decreasing the interval provided between the discs down to the limit industrially imposed by the mechanical strength of the materials and the dimensions of the particles to be eliminated.

Applicant considers, on the contrary, that this decrease in the lengths of the paths offers no interest in the case of dynamic decantation constituted by centrifugal operations, and that there should be substituted for this principle of a decrease of the paths that of the decrease of the possible variations between the average speeds of circulationtowards the axis or towards the outsideof the'liquids and solids introduced in the bowl, theoretically determined by the construction constants of the rotor and the extreme speeds of circulation towards the axis or outwards, caused, both in the radial direction and in the axial direction by the vortices of the liquids. Applicant believes that, if, at the point where the centrifugal force is maximum for a given liquid, the particles to be eliminated (whether they be solid or liquid) have not been able to reach, under the action of this centrifugal force, a speed higher than that of the liquid stream in the opposite direction, the length of the path is unimportant as well as the time spent in the bowl.

.Certain anomalies in the results obtained from centrifugal operations as compared with the results obtained by centrifugal operations in the laboratory or by mere decantation, led the applicant to assume that the rotors of centrifugal machines might, leaving aside the classical principles of the present construction, be considerably im- 5 2,808,201 Patented Oct. 1, 1957 proved both as concerns the effective hourly output and the minimum size of particles of all natures capable of being eliminated by centrifugal operations.

The invention resides in a centrifugal machine which, instead of comprising conical dishes like most of the existing machines, is provided withperfectly plane partitions perpendicular to the axis of the bowl, as thin as possible and separated by distance-pieces the thickness of which varies according to the materials to be treated and the dimensions of which are as small as possible so as to suppress all meridian partitioning inside the stack of discs by placing these inevitable distance-pieces outside the paths followed by the liquids and solids towards the axis or towards the outside of the rotor.

The machine built according to the invention comprises a bowl', provided inside with a dividing partitioning, consisting of plane discs arranged perpendicularly and concentrically with respect to the axis of the shaft driving said 'bowl in a high speed rotation motion, said discs being separated from one another by spacing washers the thickness of which has been selected according to the size and nature of the particles in suspension in the liquids to be treated in the machine.

The various features of the invention will appear from the following description when read with referenceto the appended drawing wherein:

Fig. 1 is a vertical sectional view of the centrifugal machine alongits axis of rotation; i

Fig. 2 shows, in plane view, oneof the dividing discs on which are placed spacing washers; i l i Fig. 3 shows the discin section alongthe line III- 1H ofFig.2; L,

Fig. 4 shows,sche'rnatically, the shortened path for the. liquids; p I

Fig. 5 shows, schematically, the outside path.

This description is that of a form of embodiment of the machine which is an object of the invention, this form of embodiment being mentioned only by way of amere example. p i

The rnachinecomprises a bowl 1 (Fig. 1) comprising a hub 2 for mounting it on a shaft 3 driven in a high speed rotation motion by any known means. The hub 2 may bekeyed or not onto the shaft 3.

At the center of the bowl, a distributor 4 is arranged, the base 4a of which is provided with radial channels 5 opening, at their lower end under holes 5a located at a distance from the axis of the bowl equal to that of the theoretical position of the surface of separation between two liquids, selected for the considered bowl.

The base of the distributor supports a stack of dividing discs 6, plane in shape, obtained by cutting out from metal blanks and, each one of them comprising two series of holes 6a (Fig. 2) and a series of peripheral notches 6b.

The stack of discs is obtained by securing, on a lower flange 7,.pins 8 for engagement with the holes 6a-of the, discs. The discs 6 can then be passed on the pins 8 while separating them from one another by means of spacing washers 9 also passed over the pins. e r

The flange 7 is provided with aperturesi'a coinciding with the notches 6b of the discs 6-andtheapertures 5a of the channels 5 of the distributorl. a 1

The washers 9 might be welded on the discs, but it is preferable to leave them independentofthe latterjso that it may be possible, by varying their thickness, with 3 the same discs, to constitute stackgjn which the discs are spaced from one another accordingto the materials to be treated. a

The discs are heldassembled in the shape of a stackby means of an upper'flange 10, on whichthe pins 8 arel held, by means ofnuts, for instance. 7, .t

The number of discs depends, obviously, on the dimensions of the bowl 1 and on their spacing, determined, as just set forth, according to the materials to be treated.

The pins 8 are flush with the outer plane of each one of the flanges 7 and 10 and the stack thus constituted is machined to remove any small diflerences which may occur in the discs. 7 V

The stack of discs 6 thus forms an assembly which it is not necessary to dismantle when cleaning the machine, and which is interchangeable with other stacks having various characteristics. 7

The stack of discs 6 is covered with a cap 11 fitting on the bowl 1, with an interposed seal 12, under the pressure of a clamping ring 13 screwed on the bowl 1.

In the cap 11 are fastened spouts 14 arranged radially and inclined substantially at 45 The spouts fit into notches provided in the upper flange 10 which comprises further slots 10a for the passage of the light liquid in the case of the separation of two liquids or of the single clarified liquid in the case of the treatment of a single liquid. The slots 10a face holes 16 provided in the cap 11. t

'On the cap 11 is screwed a ring 17 carrying a diaphragm 18 which makes it possible, in cooperation with the spouts 14 and by a suitable choice of said elements, to adjust the working conditions for the bowl.

A neck or collar 19 associated with the cap 11 ensures the upward motion of the lighter liquid (case of the separation of two or more liquids) or of the single liquid, to the level necessary for its evacuation. The distance from the axis of the bowl to the outlet for the liquid may be adjusted by mounting on the neck a ring which acts as a throttle.

The machine is completed by flanges 20, 21, and 22 made of elastic materials selected according to the liquids to be treated and carried by the receivers 23, 2.4 and 25 respectively. The flanges are attached to the receivers by means of clamping rings 23a, 24a, and 25a, held on them by bolts.

The opening of each flange has a smaller diameter than the opening of the rigid receiver which carries it and which is determined, once for all, when building the machine.

It is thus possible to cut down, at will, by the use of suitable flanges, the circulation of air caused by the outer wall of the rotor, which circulation may carry along a portion of the liquids out of their own receivers. The circulation of the vapours evolved by the liquids treated may also be cut down to a minimum by means of said flanges.

The rigid portions of the receivers and the flanges constitute baflles which, as just set forth, brake the circulation of air or of vapours and which may be combined with one another or placed in any location deemed suitable for adjusting said circulation.

The operation of the machine is as follows:

The machine may operate as a separator or as a clarifier. When used as a separator, the elements of the machine appear as shown schematically in Fig. 4.

The mixture of solids and liquids to be separated is introduced continuously in the direction of the arrow F into a container 26 provided, at its base, with a spout 27 extending down into the distributor 4, this in a known manner.

The mixture of the liquids rises, according to the theory of operation of such machines, through the holes a, 7a and the notches 6b, and the liquids are then evacuated, according to their specific gravity, towards the inside or towards the outside of the stack of discs 6.

The light liquid issues, in the directions of the arrows f, through the holes a of the flange 10 and the holes 16 of the bowl cap and, rising inside the collar 19, is evacuated through the space 28 between the receivers 24 and 25.

The heavy liquid comes out along the arrows f and rises up to the spouts 14, through which it passes to reach the adjustment diaphragm 18 and to be evacuated through the space 29 between the receivers 23 and 24.

The solid, heavy impurities slide outwards, penetrating or not between the discs 6 according to their size and they are partly evacuated together with the heavy liquid and partly applied on the inner Wall of the bowl 1 and of the bowl cap 11.

The outlet device provided for the heavy liquid makes it possible, by a proper choice of the lengths and diameters of the spouts, to ensure the evacuation of a large portion of the solid impurities, denser than the heavy liquid, by acting on the evacuation speeds of the solids and of the heavy liquid.

The light, solid impurities, always fine, slide inwards of the stack of discs 6 and are housed in the silt chamber 15 formed between said stack and the distributor 4, this under the condition that these impurities be lighter than the light liquid.

The chamber 15 may be provided with an air-evacuating device which has not been shown.

. In principle, the surface of separation of the liquids through the stack of discs 6 may be limited by the chaindotted circumference line shown in Fig. 2. For one direction of rotation R, the light liquid moves substantially along the path f, while the heavy liquid moves along the trajectory f.

The elimination of the solid materials having a diameter larger than the spacing of the discs is ensured by the shape of the notches 6b towards the outside of the discs.

When the machine is used as a clarifier, there is an advantage in causing the liquid to circulate as far as possible from the axis of rotation and even outside the stack of discs. The eddy currentscreated outside the stack are of no importance, since the single liquid has to go through the stack of discs, by following the path covered by the light liquid in the machine used as a separator.

To this eifect, the orifices 7a of the lower flange 7 are stopped by plugs 30 (Fig. 5), and the spouts 14 of the bowl cap are stopped by plugs 31.

The liquid to be clarified is introduced along the arrow F and, passing through the radial channels 5 of the distributor '4, it passes through the stacks of discs 6 following the direction of the arrows f, and is evacuated through the space 28 between the receivers 24 and 25.

It should be noted that, in some cases, the orifices 7a should be stopped even when the machine is to operate as a separator.

' What I claim is: V

1. In a centrifugal machine for separating and clarifying liquids, a rotor consisting of a bowl; a vertical shaft located on the axis of said bowl for driving it in a high speed rotating motion; a distributor bringing the liquid to be treated to the center of said bowl; a stator comprising a container divided into several chambers for receiving the various divided portions of the liquid treated; a separator unit located inside said bowl and comprising a plurality of plane thin dividing discs arranged perpendicularly and concentrically with respect to the axis of the shaft driving the bowl, said dividing discs being spaced from each other by spacing washers that are located outside of the outward spiral path of the heavier liquids and solids and outside of the inward spiral path of the lighter liquids and solids; a plurality of orifices formed in said plane dividing discs, said orifices being adapted to be left free or stopped according to whether it is desired to allow the liquid to be treated to reach the axis of the bowl or to send it back towards the outside of the discs; a plurality of assembly holes formed in said plane dividing discs; support rods passing alternately through said assembly holes in the dividing discs and the spacing washers, thus forming a stack of said discs; and two flanges located respectively at the ends of said stack and in which the ends of said support rods are fixed so as to form with said dividing discs and said spacing washers, a removable block, said block being itself built in a dynamically balanced state.

2. In a centrifugal machine for separating and clarifying liquids, a rotor consisting of a bowl; a vertical shaft located on the axis of said bowl for driving it in a high speed rotating motion; a distributor bringing the liquid to be treated to the center of said bowl; a stator comprising -a container divided into several chambers for receiving the various divided portions of the liquid treated; a separator unit located inside said bowl and comprising a plurality of plane thin dividing discs arranged perpendicularly and concentrically with respect to the axis of the shaft driving the bowl, said dividing discs being spaced from each other by spacing washers that are located outside of the outward spiral path of the heavier liquids and solids and outside of the inward spiral path of the lighter liquids and solids, said spacing washers having as small a diameter as possible and a thickness which depends upon the size and nature of the particles in suspension in the liquids to be treated in the machine; a plurality of orifices formed in said plane dividing discs, said orifices being adapted to be left free or stopped according to Whether it is desired to allow the liquid to be treated to reach the axis of the bowl or to send it back towards the outside of the discs; a plurality of assembly holes formed in said plane dividing discs; support rods passing alternately through said assembly holes in the dividing discs and the spacing washers, thus forming a stack of said discs; and two flanges located respectively at the ends of said stack and in which the ends of said support rods are fixed so as to form with said dividing discs and said spacing washers, a removable block, said block being itself built in a dynamically balanced state and being adapted to accommodate spacing washers the thickness of which varies from one block to another in a group of said blocks, each block in said group of blocks thus being capable of being assigned to a predetermined type of liquid to be treated in the machine.

3. A centrifugal machine according to claim 2, in which the plane dividing discs have a central opening through which the distributor of the machine passes for forming around said distributor a silt chamber for the light liquid, the upper flange of the stack of dividing discs being provided with apertures located above said chamber for allowing the evacuation of said light liquid.

4. A centrifugal machine according to claim 2, in which the plane dividing discs have a central opening through which the distributor of the machine passes for forming a silt chamber; the upper flange of the stack of dividing discs being provided with apertures located above said chamber for allowing the evacuation of the light liquid flowing through said silt chamber; the orifices formed in the plane dividing discs comprising radial slots located on the peripheries of said discs and the lower flange of the stack of dividing discs being provided with openings located opposite said slots in the dividing discs so that the inlet of liquid is effected inside said stack with no risk of clogging between the discs.

5. A centrifugal machine according to claim 2, in which the plane dividing discs have a central opening through which the distributor of the machine passes for forming a silt chamber; the upper flange of the stack of dividing discs being provided with apertures for allowing the evacuation of the light liquid flowing through said silt chamber; the orifices formed in the plane dividing discs comprising radial slots located on the peripheries of said discs and the lower flange of the stack of dividing discs being provided with openings located opposite said slots in the dividing discs so that the inlet of liquid is effected inside said stack with no risk of clogging between the discs, said lower flange openings being adapted to be closed by plugs thereby compelling the liquid to pass outside the stack.

6. in a centrifugal machine for separating and clarifying liquids, a fixed stator member provided at its upper central portion with a downwardly extending conduit for introducing said liquids; a rotor member adapted to be rotatably driven at high speed and including a substan tially cylindrical bowl and a cover member detachably and hermetically fixed on the upper part of said bowl; a driving shaft centrally mounted on the lower part of said bowl; a distributor mounted centrally of said rotor member and in communication with said liquid conduit; a plurality of radially disposed channels formed between the lower face of said distributor and the base of said bowl; a cylindrical self-cleaning separator unit comprising a stack of flat discs of equal diameters, said discs being spaced apart and mounted on and around said distributor; a plurality of orifices formed in said discs in vertical register to form vertical passages through said stack, each of said passages being adapted to communicate with the outer extremity of one of said radially disposed channels; an outer annular chamber formed between the inner walls of said bowl and the outer side of said stack to provide a passage for heavier liquids and to form a deposit chamber for heavier solid matter; an inner silt chamber formed between said distributor and the inner side of said stack to provide a passage for lighter liquid fractions and to form a deposit chamber for lighter solid matter; and separate channel means communicating respectively with said outer and inner chambers and leading into parts of said stator member for taking ofl. the separated liquids.

7. In a centrifugal machine as claimed in claim 6 and which is especially adapted for the clarification of liquids, the lower orifices of said vertical passages in the separator unit being closed by plugs and the channel means leading from said outer chamber also being closed, so that the entire liquid flow from said bowl takes place inwardly through said discs and then upwardly into said channel means leading from said inner chamber.

8. In a centrifugal machine for separating liquids, a fixed stator member provided at its upper central portion with a downwardly extending conduit for introducing said liquids; a rotor member adapted to be rotatably driven at high speed and including a substantially cylindrical bowl and a cover member detachably and hermetically fixed on the upper part of said bowl; a driving shaft centrally mounted on the lower part of said bowl; a distributor mounted centrally of said rotor member and in communication with said liquid conduit; a plurality of radially disposed channels formed between the lower face of said distributor and the base of said bowl; a cylindrical self-cleaning separator unit formed by a plurality of flat thin discs arranged at right angles to and concentrically with the axis of said bowl, said discs forming separator plates and being provided with vertically aligned assembly holes; support rods extending through the aligned assembly holes of said discs; a flange forming the lower extremity of said distributor, said rods being fixed at their lower extremities to said flange and said plates being spaced apart by spacing washers threaded on said rods, the stack assembly thus formed being clamped together by nuts screwed on the upper extremities of said rods; a plurality of orifices formed in said discs in vertical register to form vertical passages through said stack assembly, each of said passages being adapted to communicate with the outer extremity of one of said radially disposed channels; an outer annular chamber formed between the inner walls of said bowl and the outer side of said stack assembly to provide a passage for heavier liquids and to form a deposit chamber for heavier solid matter; an inner silt chamber formed between said distributor and the inner side of said stack assembly to provide a passage for lighter liquid fractions and to form a deposit chamber for lighter solid matter; and separate channel means communicating respectively with said outer and inner chambers and leading into parts of said stator member for taking off the separated liquids.

9. In a centrifugal machine as claimedin claim 8, in which said cylindrical separator unit itself is in a dynamically balanced state.

10. In a centrifugal machine as claimed in claim 8, in

which the orifices formed in said discs comprise radially that they-liesubstantially out ofthe outward spiral path disposed slots spaced apart uniformly on the periphery of theheavier liquids and solids and also out of the inof said discs and extend inwardly at least to the critical wardspiral path of the lighter liquidsand solids. diameter of the surface of separation of the liquids treated in the machine, said slots communicating with openings 5 i a 7 References Cited inthe file of this Patent formed in said flange so as to permit communication of t V UNITED STATES PATENTS said vertical passages with the outer extremities of said 2,403,089 L'ars n, 2, 1946 radially disposed channels.

11. In a centrifugal machine as claimed in claim 8, FOREIGN PATENTS in which said support rods and spacing washers are s0 10 1 8,816 Sweden Jan. 17, 1905 disposed in relation to said vertical passages for the liquid, 15,480 Great Britain 1911

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