US1613579A - Centrifugal separator - Google Patents

Description

Jan. 4, 1927.

J. W. H INCHLEY ET AL x CENTRIFUGAL SEPARATOH 1 Filed Jan. '25, .926 2 Sheets-Sheei 1 mvsm'ows MM [My caulk. M

h 1 B W QMQ pill Patented Jan. 4, 1927.

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JOHN WILLIAM HINGHLEY AND (II-TABLES SCOTT WATSON, OF WESTMINSTER, LON- DON, ENGLAND, ASSIGNORS OF ONE IHIRD TO CHARLES SAMUEL GARLAND, OF

LONDON, ENGLAND.

CENTBIFUGAL SEIARATOR.

Application filed January 23, 1926, Serial No.

This invention relates to centrifugal separators primarily intended for separating solids from fluids of lesser density but also applicable in some cases to effect separation between two liquids of different densities, for example between the heavier and lighter phases of an emulsion. In this specification the heavier content of the material (whether it be solid or'liquid) will be referred to as the solids, and the lighter content, (whether it be liquidor gaseous) as the liquid.

The present invention is concerned with centrifugal separators of the type in which the separating vessel or bowl, rotatable about a vertical axis, is subdivided at a horizontal plane into two axially separable parts, and the solids are discharged through the gap formed between the said parts when separated, while the liquid is withdrawn from another region of the bowl, say at the top or bottom thereof. The upper and lower bowl parts are so shaped that the chamber enclosed by them converges towards the aforesaid plane at which the bowl is subdivided; for example the bowl parts may be in the form of two dished members with their concave faces opposed to one another, or one of the bowl parts may be dished and the other a substantially flat disc.

The object of the present invention is to provide an improved machine of the above type designed for continuous operation and embodying a novel method of controlling automatically the opening between the bowl parts for the discharge of the solids.

According to this invention a centrifugal separator of the type referred to above having the bowl formed in two axially separable parts constrained towards each other by resilient means is characterized in that a brake surface is presented within the bowlv chamber to the material undergoing treatment therein and is so situated in relation to the meeting edges of the bowl parts as to be traversed by the solids deposited there when a predetermined accumulation has been made, and in that the opening of the bowl parts to provide the discharge outlet for solids is controlled by the increase in frictional drag which takes place between the material rotating with the bowl and the brake surface aforesaid as the solid deposit accumulates.

In the preferred form of this invention 83,233, and. in Great Britain February 4, 1925.

the brake surface is a stationary surface, but it is within the invention to employ a surface which is rotated at a speed or in a sense different from that of the driven portion or portions of the bowl.

There are various ways by which the change in frictional resistance at the brake surface may be employed to control the opening of the bowl parts. For example the member which provides the surface aforesaid may be mounted for limited angular niovement under the action of the frictional drag and against a resilient constraining force (e. g. that of a spring) arranged to give way when the frictional resistance at the surface exceeds a predetermined value. In this case the normally stationary member is operatively connected to the bowl parts or to one of them in such manner that angular movement of the member is converted into axial separation of the bowl parts.

Both of the bowl parts may rotate or one of them may be fixed. In one arrangement according to the invention in which both parts are rotated, one of them, say the lower one is directly driven, and the other part, e. g. the upper one is driven by the lower part through a coupling which permits of limited angular movement of the upper part in relation to the lower one in a backward direction, that is a direction opposed to that in which the lower part is rotated. The upper bowl part is constrained against backward movement by spring means arranged to give way when the drag on the upper part imposed by the frictional resistance between the solid deposit and the stationary surface aforesaid exceeds a predetermined value. Means are provided to convert the resulting backward movement of then per bowl part into axial separation as be ore. For this purpose the two bowl parts may be in screw-threaded engagement one with the other, the screw-thread being coaxial with the bowl and of opposite hand to the direction of rotation of the bowl parts.

In a further form of the invention only one of the bowl parts (say the lower one) is rotated and the other part (say the upper one) is arranged to present the aforesaid stationary surface. In this case the normally stationary bowl part is mounted for limited angular movement against the constraint of a spring, and means are provided as before for converting such angular movement into separation of the bowl parts.

Two difierent forms of apparatus embodying the inventionwill now be described with reference to the accompanying drawings in which:

Figure 1 is a central sectional elevation of the first form of apparatus, and

Figure 2 is a similar View of the second form. Like reference numerals indicate like parts both figures. In the first example the bowl parts are in the form of two dished members 5, 6 ofsubstantially the same diameter and coaxially arranged with their concave faces opposed to one another. The lower part 6 of the bowl is supported on a bearing 7 and is directly driven by any convenient means (not shown). Extending upwardly from the lower part 6 is a central spindle 8 from which the upper bowl part 5 is suspended in the following manner. The upper part 5 is connected by a web 9 to a boss 10 which is a loose fit on the central. spindle 8. A sleeve 11 provided with a flange 12 is keyed to the spindle 8 near its upper end, and secured to the upper end of the boss 10 is a flanged portion 13 similar to the flanged portion of the sleeve 11. The two flanges 12, 13 between which there is a gap, are coupled together by several spring rods or blades l l extending vertically from the one flange to the other. The bowl parts are thus interconnected so that they rotate together, the spring rods 14 per mitting, under restraint, a limited angular movement of the upper part in relation to the lower one. The spring rods are enclosed by a casing 15, which is in screw-threaded attachment with the flanged portion 13 of the boss 10 and is a loose fit on the flanged portion of the sleeve 11. The stationary surface hereinbefore referred to is provided by an outwardly directed lip 16 at the lower end of a fixed tubular member 17 which surrounds the inter-connected flanges 12, 13 and at its lower end projects into the bowl chamber. The lip 16 forming the stationary surface is directed toward the meeting edges of the bowl parts but is spaced apart at a predetermined distance therefrom. The lower end of the boss 10 which carries the upper bowl part is in screw-"threaded engagement with a central socket 18 on the lower bowl part 6. The screw-thread on the engaging parts is of such hand that angular movement of the upper part 5 in relation to the lower one 6 in a backward direction (i. e. opposed to the direction of rotation of the lower part) will result in axial movement of the upper part away from the lower one, that is to say the bowl parts will be separated at their meeting edges and a circumferential gap provided for the outlet of the solid deposit from the bowl. Instead of the boss 10 being in screwthreaded engagement with a socket on the lower bowl part, the boss may be formed with an internal screw-thread to engage a corresponding thread on the spindle 8.

hen the machine is first started the material to he treated (i. e. the mixed solids and liquid) .is fed from a hopper 19 into the interior of the tubular member 17 and from thence is directed by a guide plate 20 into an annular trough 21 provided by the web 9. Through apertures 22 in the web the material then passes into the lower half i of the bowl chamber At this stage the two bowl parts are rotating together as a single unit, the spring rods 14; operating to prevent relative movement between them. It will be understood that the'material undergoing treatment in the bowl is rotating with it and is traversing the stationary surface 16 at the lower end of the member 17. The friction at this surface depends mainly upon the viscosity of the material and the speed of rotation of the bowl. The solids are deposited in the wedge-shaped pocket formed at the meeting edges of the bowl-parts and when a certain accumulation has taken place, depending on the relative position of the surface 16, the solid deposit comes into contact with said surface and the frictional forces are enormously increased. The frictional drag between the rotating solid deposit and the stationary surface acts as a brake to the bowl parts, and as the upper part is capable of being retarded by virtue of its resilient coupling with the lower part, the brake tends to eflect such retardation. The spring rods 14 are of such strength that while the friction due to the viscosity of the liquid is not sufiicient to overcome the constraining force of the rods, the friction caused by the solid deposit is suficient to do so and thus to effect aXial separation of the bowl parts.

The machine operates continuously the solids being discharged through the circumferential gap between the two halves of the bowl and the liquid being withdrawn from the top of the bowl. The bowl parts are housed in a casing 23 provided with a cover 24 from which the tubular member 17 is suspended. The discharged solids are withdrawn from the lower end of the casing 23. The liquid rising in the bowl chamber flows over a lip 25 at the upper end of the top bowl part 5, into an annular compartment 26 formed by fixed baffles 27, 28, and from thence the liquid is withdrawn by a pipe 29. It will be understood that during operation there is always an accumulation of solids in the wedge-shaped pocket between the upper and lower halves of the bowl. If the dis charge of solid material is not wholly compensated by the accumulation of further solids in the pocket, and the deposit is reduced to an extent such that it no longer contacts with the stationary surface 16, the braking action which is keeping the bowl parts separated is removed and under the restoring action of the spring rods 14 the upper bowl part is again forced into contact with the lower one and the outlet for solid material thereby closed. The parts are maintained in this position until the necessary further accumulation of solids has been made.

In operation the solid deposit may not be reduced to such an extent that the outlet to solids is completely closed. The friction at the brake surface varies according to the depth of the deposit and the variation may be, and normally would be, within such limits that the outlet for solids would never actually be closed although the area of the out let would vary.

An auxiliary brake constituted by a plunger is provided for application by hand to a rim 31 on the upper bowl part so that the bowl parts may be separated when desired say when the machine is being cleaned out.

In the second illustrated example (Figure 2) embodying the invention only one of the bowl parts, namely the lower one 6, is rotated, while the upper part 5 is arranged to provide the aforesaid stationary surface. The lower bowl part 6, is a dished member supported at its lower end on a bearing 7 and having a central spindle 8 extending up wardly therefrom. The upper bowl part 5 is in the form of a disc extending outwardly from a central boss which surrounds the spindle 8. The boss 40 is spaced apart from the spindle and in the annular gap between them a fixed tubular member 41 is located. The member 41 is suspended from the cover 24 of the casing 23 which encloses the bowl. The spindle 8 fits loosely within the member 41, while the boss 40 is in screw-threaded engagement at 42 with said member. The screw-thread on the engaging parts is of such hand that angular movement of the upper bowl part 5 in the direction of rotation of the lower part 6, will cause upward axial movement of the upper part and so open the outlet for solid material. Such angular movement of the upper part is opposed by a spring 43 located in tension between the boss 40 and the casing 23. The fixed end of the spring is connected to a screw-threaded rod 44, and by means of a nut 45 in engagement with this red the tension on the spring may be adjusted. lVith the present construction the brake surface (indicated at 16) presented by the upper bowl part is traversed by the solid deposit immediately the latter starts to accumulate at the closed outlet from the bowl. As the deposit increases the frictional resistance at the stationary surface 16 increases until it reaches a critical value at which the spring 43 constraining the upper bowl part against angular movement is overcome and the mouth of the bowl is opened.

The material to be treated is fed from a hopper 19 through a conduit 46 into a dished portion 47 of the upper bowl part. The ma tcrial then passes through apertures 48 in the upper part into the lower portion of the bowl. The discharged solids pass as before into the lower portion of the casing 23 and from thence are withdrawn. The liquid is discharged through apertures 48 in the upper part 5, over a peripheral lip 49 into an annular trough 26 from which it is withdrawn through a pipe 29. I

In order to permit of the bowl being cleaned by flushing with water, and also to furnish a stop as hereinafter described, the following means are provided for separating the bowl parts. A wire 50 is secured at one end to the boss 40 and at the other is coupled to a screw-threaded rod 51 which engages in a bush 52 secured to the casing 23. The connection between the wire 50 and the boss 40 is such that when the wire is pulled (by appropriate rotation of the rod 51) towards the right in Figure 2 the boss will be rotated in a direction to separate the bowl parts, that is against the action of the spring 43 which is tending to close the bowl. After cleaning, the rod 51 is reset so that the wire 50 does not interfere with the normal opera tion of the spring 43. The normal setting of the wire 50 is such that it acts as a stop to limit the downward movement of the upper bowl part so that the latter is never in actual contact with the lower part. If the two bowl parts made metal-to-metal contact the friction at starting would be very great and wear at the meeting surfaces excessive.

In a further example according to the invention but not illustrated in the drawings the lower bowl part is fixed and is in the form of a substantially fiat disc while the upper bowl part, which is dished, is rotated. The brake surface is provided by an abutment which projects through an openingin the fixed bowl part. This abutment is mounted for limited angular movement under the action of the frictional drag when the machine is running and is so operatively connected to the upper bowl part that angular movement of the abutment is converted into axial movement of the upper part of the bowl away from the lower one. In place of the aforesaid abutment the lower bowl part may be arranged to provide the brake surface. pose the lower part is in screw-threaded engagement with a fixed sleeve surrounding the central spindle of theupper part. The

screw-thread may be of quick pitch, the

spring constraining the lower bowl part agamst angular movement belng a coiled ltlO iii)

Conveniently for this pur- V spring located coaxially with the bowl. As will be understood other modifications may be made in the construction of the apparatus withoutdeparting from the principle of the invention. In the foregoing examples the brake surface is of fixed area; if desired however it may be provided by an expansible device adjustable by manuallyoperable means to vary the effective area of the brake surface oresented within the bowl.

What we claim as our invention and desire to secure by Letters Patent is:

1. In a' centrifugal separator of the type described the combination of two bowl parts which are axially separa le to provide discharge opening for solids and which are shaped to enclose bet .veen them a chamber which converges towards the region at which the discharge opening aforesaid will be provided, a bralre surface situated within the bowl chamber in .a position to be traversed by the solid deposit wh ch accumulates within the bowl in the region of the discharge opening aforesaid, and means for utilizing variations in the frictional resistance between the brake surface and the solid deposit which rotates with the bowl, to control the separation and approach of the bowl parts.

2. In a centrifugal separator of the type described the combination of two bowl parts which are axially separable to provide be tween their peripheral edges a discharge outlet for solids, resilient means to constrain the bowl parts towards each other, a brake surface arranged within the separating chamber to be traversed by the solids deposited within the bowl in the region of the discharge outlet aforesaid, and means to convert an increase in frictional drag between the solid deposit and the brake surface aforesaid into an axial separating movement of the bowl parts.

3. In a centrifugal separator of the type described the combination of a bowl formed in two parts which are axially separable to provide between their peripheral edges a discharge outlet for solids, a member mounted for limited angular movement about the axis of rotation of the bowl and arranged to present within the bowl chamber a surface to be traversed by the solid deposit which accumulates at the discharge outlet aforesaid, resilient means arranged to constrain the member aforesaid against angular movement, but, when the frictional drag of the solid deposit on the aforesaid surface of the member exceeds a predetermined value, to give way to an extent depending on the amount by which said value is exceeded, and means to convert the limited angular movement of the member aforesaid into axial separation of the bowl parts.

4- In a centrifugal separator of the type described the combination of two co-operating bowl parts, one rotatable and the other normally stationary, shaped internally to provide pocket for the reception of solids, said pocket being bounded partly by the surface of one bowl part and partly by the surface of another, means to permit of limited angular movement of the normally stationary part about the axis of rotation of the other part, resilient means arranged to constrain'the normally stationary bowl part against angular novement but, when the frictional drag of the solid deposit on the internal surface of the normally stationary part exceeds a predetermined value, to give way to an extent depending on the amount by which said value is exceeded, and means to convert the limited angular movement of the normally stationary part into an axial movement of said part away from its neighhour.

5. In a centrifugal separator of the type described the combination of two co-operating bowl parts, one otatable and the other normally stationary, shaped internally to provide a pocket for the reception of solids, said pocket being bounded partly by the surface of one bowl part and partly by the surface of the other, means to permit of limited angular movement of the normally stationary part aboutthe axis of rotation of the other part, a fixture with which the normally stationary part is in screw-threaded engagement, the screw-thread being coaxial with the bowl and of such hand that the aforesaid limited angular movement of the normally stationary bowl-part will effect axial movement of said Dart awa from its 7 neighbour, and spring means arranged to constrain the normally stationary part against angular movement but, when the frictional drag of the solid deposit on the internal surface of the normally stationary part exceeds a predetermined value, to give way to an extent depending upon the amount by which said value is exceeded.

6. In a centrifugal separator of the type described the combination of two (Jo-operating bowl parts, shaped internally to provide a pocket for the reception of solids, said pocket being bounded partly by the internal surface of one bowl part and partly by the internal surface of the other, driving means for one of said parts, a coupling between the driven part and the other part arranged to permit of limited angular movement of said other part in relation to the driven part in a backward direction, a stationary member located within the bowl chamber in a position to be traversed by the solids deposited therein when a predetermined accumulation has been made, spring means arranged to constrain the indirectly driven bowl part against backward movement but to give way when the frictional drag on said part, imposed by the frictional resistance between the solid deposit and the stationary member aforesaid, exceeds a predetermined value, and means to convert backward angular movement of the indirectly driven bowl-part into an axial movement of said part away from its neighbour.

7. In a centrifugal separator of the type described the combination of two bowl parts shaped internally to provide a pocket for the reception of solids, said pocket being bounded partly by the internal surface of one bowl part and partly by the internal surface of the other, driving means for one of said bowl parts, a screw-threaded connection between the driven bowl part and the other part, the screw-thread being 0 axial with the bowl-parts and of opposite hand to the direction of rotation ofthe driven part, a resilient coupling between the driven bowlpart and the other part arranged to permit, under restraint, a limited angular movement of said other part in relation to the driven part in a backward direction, and a stationary member located within the bowl in a position to be traversed by the solids deposited in the pocket aforesaid when a predetermined accumulation has been made.

8. In a centrifugal separator of the type described the combination of two bowl-parts arranged one above the other and shaped to provide a separating chamber which converges towards the meeting edges of the bowl parts, driving means for the lower bowl part, a plurality of spring rods located parallel to and symmetrically about the aXis of rotation of the bowl and arranged to couple the upper bowl part with the lower one and to permit, under torsional control, a limited angular movement of the upper part in relation to the lower one in a backward direction, a stationary member located within the bowl-chamber in a position to be traversed by the solids deposited at the meeting edges of the bowl parts when a predetermined accumulation has been made, and means to convert backward angular movement of the upper bowl part into an axial inovement of said part away from its neighour.

9. In a cen rifugal separator of the type described the combination of two bowl parts, one rotatable and the other non-rotatable, shaped internally to provide a chamber which converges towards the meeting edges of the bowl parts, means to permit of axial movement of the non-rotatable bowl part away from its neighbour, a member mounted for limited angular movement, about the axis of rotation of the rotatable bowl part and arranged to present within the bowl chamber a surface to be traversed by the solid deposit when a predetermined accumulation has been made at the meeting edges of the bowl parts, resilient means arranged to constrain the member aforesaid against angular movement but, when the frictional drag of the solid deposit on the aforesaid surface of the member exceeds a predetermined value, to give way to an extent depending upon the amount by which said value is exceeded, and means to convert the limited angular movement of the member aforesaid into an axial movement of the non-rotatable bowl part away from its neighbour.

10. In a centrifugal separator of the type described the combination of two bowl parts which are axially separable to provide a discharge outlet for solids and which are shaped to enclose between them a chamber which converges towards the region of the discharge outlet aforesaid, a brake surface arranged within the bowl chamber to be traversed by the solid deposit which accumulates within the bowl in the region of the discharge outlet aforesaid, means for utilizing variations in the frictional resistance between the brake surface and the solid deposit which rotates with the bowl, to control automatically the separation and approach of the bowl parts, and auxiliary hand-operable means to effect separation of said parts.

In testimony whereof we have signed our names to this specification.

JOHN WILLIAM HINGI-ILEY. CHARLES SCOTT WATSON.

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