US2302381A - Centrifugal separator - Google Patents

Description

Nov. 1'], 1942. A. T. SCOTT 2,302,381

CENTRIFUGAL SEPARATOR Filed April 12, 1940 a Q Q v Q 9 S r M r INVENTOR 7i HshfonT Scott A TTORNE Y I I Patented Nov. 17,1942

Ashton '1. Scott, Bryn Mawr, Pa aulgnor es Corporation, Philadelphia, Pa, a corsharp! notation of Delaware The Application April 12, 1940, Serial No. 329,250

14 Claims.

This invention relates to a centrifugal machine designed to effect separating or concentrating operations on fluid mixtures. Machines constructed in accordance with the invention may be used to separate one or more liquid or solid constituents from a liquid mixture under treatment, to concentrate emulsions, or for other centrifugal separating operations.

In the operation of a centrifugal separator, it is necessary that the liquid passed to the machine for centrifugal treatment be accelerated to a rotational velocity approximately equal to that of the centrifugal rotor itself, in order that the full effectiveness of the machine may be attained. If this acceleration is accomplished only gradually after the liquid is fed to the centrifugal rotor, the efficiency of the centrifugal operation will be impaired, since it is desirable that the maximum available centrifugal force be applied to the material under treatment for as long a time as may conveniently be accomplished.

In order to efiect rapid acceleration of material to the speed of the centrifugal rotor, it is common to cause this material to impinge against a radially extending accelerator wing fairly promptly after it is fed to the rotor. When such a radial wing strikes the material fed to the rotor; the resulting impact is quite violent, and as the result of this violent impact the material under treatment is sometimes damaged or the efliciency of the ensuing separating opera: tion impaired.

An. object of the present invention has been to provide a centrifugal separator with an arrangement for rapidly accelerating material to the speed of the rotor without subjecting that material to the violent impact caused by radially extending accelerator wings.

It is also sometimes desirable to effect intimate contact between constituents of a mixture fed to a centrifugal rotor in order to cause some chemical or physical reaction or change to occur in one or more of such constituents before subjecting the resulting mixture to centrifugal separation in another part of the same rotor. The French patent to P. T, Sharples, 522,744, illustrates a machine designed to effect such a sequence of contacting and separating steps, and illustrates a few instances of uses of such machines; i. e., in the treatment of vegetable or mineral oils with alkalies or acids.

A further object of the present invention has been to provide an improved centrifugal machine capable of causing intimate contact between contor, accelerating the mixture rapidly and smoothly to the speed of the rotor, and thereafter effecting centrifugal separation of the constituents of the resulting mixture.

Still further objects and advantages of the invention will be evident from a reading of the following specification in the light of the attached drawing, in which,

Figure 1 is a side elevation of the centrifugal rotor of the invention, with parts broken away to illustrate the interior construction,

stituents of a mixture fed to a centrifugal ro- 55 Figure 2 is a detailed vertical cross section through the lower part of the rotor illustrated in Figure 1, and

Figure 3 is a cross section taken on the line 3-3 of Figure 2.

In the embodiment of the invention illustrated in the drawing, the centrifugal rotor l0 comprises a base portion if having an upstanding flange to which the main body portion I! of the rotor is secured. The top portion iii of the rotor is provided with discharge outlets and weirs of conventional construction (not shown), and this top portion may be secured to the main body portion by screw threaded engagement therewith. The top portion l3 terminates in a reduced neck It which is screw threaded for engagement with a spindle coupling for driving the rotor. A feed nozzle l5 projects into a feed passage in a boss IS on the base of the rotor, and fluid passed to the rotor through this nozzle is accelerated to the speed of the rotor and thereafter subjected to centrifugation in the main body of the rotor, in a manner which will be described hereinafter.

The above-described features constitute no part of the-present invention, and are merely illustrative of one type of machine to which the invention may be applied. The features of the present invention pertain to the means for accelerating material to the speed of the rotor after discharge from the nozzle I5, and for effecting intimate contact between constituents of the material fed to the rotor during such acceleration.

The upper surface of the base portion ll of the rotor may extend conically from the inner circumference of the main body of the rotor toward the opening surrounding the feed nozzle l5, and the novel arrangement of the present invention may be assembled directly above this conically extending portion. This novel accelerator may comprise an outer annular wall I! adapted to fit snugly within the inner circumferential wall of the main body of the rotor. A plurality of axially spaced radially extending accelerator wings I8 are secured within the circumferential wall l1, and a plurality of closely spaced superposed annular discs l9 are secured to these accelerator wings at the inner ends thereof. A top disc may be secured to the upper end of the wall l1, and a conical boss or other suitable type of deflector 23 is secured centrally to the under side of the disc 20.

The top disc 20 is provided with openings H for passage of liquid upwardly from the preliminary feed section F of the rotor occupied by the accelerator comprising the discs l9 into the separating section S of the rotor. a

The separating section of the rotor, which overlies the preliminary feed and accelerator section, may include a plurality of radially extending wings 22 for maintaining the liquid in this separating section in rotation at the same rate as the rotor itself. The top portion [3 of the rotor maintains the accelerator wings 22 in place against the disc 20, and this tip portion is provided with one or more outlets for the effluent or eiiluents from the machine. In case the machine is to be used for separating a mixture containing two immiscible liquids from each other, for example, the top portion will be provided with two outlets, and the outlet for the heavier stratifled eiliuent will be provided with an interchangeable ring dam, in'order that the necessary adjustment may be made to maintain the stratified liquids in balance against each other, as will be well understood by those skilled in the art.

In the operation of the centrifugal separator described above, the material to be subjected to the centrifugal separating operation is jetted liquid because of frictlom As a consequence of this fact, damage to the material under treatment by reason of violent impact with accelerator wings is avoided, but the liquid is nevertheless rapidly accelerated to the desired speed by frictional engagement with the discs. By the time the liquid reaches the zone of the rotor occupied by the radially extending wings I! or the wings 22, it has attained substantially the same rota.-

through the feed nozzle I! upwardly into the preliminary feed section F of the rotor. This material, which may comprise two or more immiscible liquids, impinges against the deflector 23, and is thus deflected laterally into the spaces between the discs l9. Friction between the discs I! and the liquid fed into the space between them causes this liquid to be rapidly accelerated, and as the liquid is accelerated it is forced outwardly through the spaces between the discs under the influence of centrifugal force. The liquid is thus passed through the discs to the outer radial portion of the'feed section F occupied by the accelerator wings l8. It is passed through the openings 2| in, the top disc 20 of the feed section of the rotor into the separating section S. The separating function, e. g.. the separation of immiscible liquids from each other and/or separation of a solid constituent from liquid, takes place in the separating section S of the rotor, solids being deposited on the rotor wall, and immiscible liquids discharged in liquid balance againsteach other through the conventional outlets (not shown). The accelerator wings 22 maintain the material under treatment at the speed of rotation of the rotor during passage thereof through the separating section 8.

In case the machine is to be used for concentrating an emulsion, the operation will be the same as that described above, except that the materials separately dischargedwill be relatively richer and'poorer, respectively, in the dispersed phase than the material fed to the rotor, instead of being substantially pure liquids. I

The manner in which the objects of the invention have been attained will now be apparent. The discs I9 do not strike the liquid under treatment by impact of a surface moving at right angles to the liquid, but eifect acceleration of the tional velocity as the rotor itself, and there is,

therefore, no sudden and violent impact entailed in the performance of the'accelerating function of the wings l8 and 22. The contact between constituents of a mixture on passing through the discs I9 is very intimate because of the close I thereof incident to the centrifugal treatment,

this intimate engagement in passing through the discs 19 accomplishes the desired result very efiectively.

While it is desirable that the material under treatment be rapidly accelerated during passage through the feed section IE, it is undesirable that any substantial part of the mixture be stratified and remain in this section. Stratification is almost completely avoided in this section because of the small time consumed in'passing any part of the mixture through the section, and especially because of the high degree of turbulence generated in that section by frictional engagement of the liquid with the discs IS. The openings 2| in the top disc 20 of the feed section F of the rotor occupy a radial position between the inner circumferences of the rotor wall and the layer of liquid maintained in the rotor under centrifugal force during the operation thereof, and the location of these openings approximately midway of the depth of liquid in the rotor also assists in causing the liquid mixture to be passed upwardly into the separating section B of. the

rotor from the feed section F without stratification prior to reaching the separating section.

It will be obvious to those skilled in the art that the above description and attached drawing represent but one of many possible forms of the invention. I do not therefore wish to be limited except by the scope of the sub-joined claims.

I claim:

1. In a centrifugal separator, a rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating,

spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

2. In a centrifugal separator, a rotor, and means to feed fluid mixture axially to said rotor at approximately the axial center line thereof, said rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through spaces between successive discs, and a deflector adapted to cause a fluid mixture fed axially to said rotor to be deflected into the spaces between said discs, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other.

and having central feed openings, and the space surrounding said discs lying in the line of liquid rality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through spaces between successive discs, and a conical deflector adapted to cause a fluid mixture fed axially to said rotor to be deflected into the spaces between said discs, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

4. In a centrifugal separator, a rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through the spaces between successive discs, and radially extending accelerator wings occupying the space between the outer circumferences of said discs and the inner circumference of the rotor wall, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

5. In a centrifugal separator, a rotor compris= ing a preliminary feed section in which liquid under treatment is'accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through the spaces between successive discs, and a disc overlying said plurality of closely spaced discs for separating the feed section of the rotor from the separating section of the rotor, said last-mentioned disc being perforated to permit passage of fluid from the feed section of the rotor to the separating section thereof, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other andhaving central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

6. In a centrifugal separator, a rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through the spaces between successive discs, and a disc overlying said plurality of closely spaced discs for separating the feed section of the rotor from the separating section of the rotor, said last-mentioned disc being perforated in a zone between the inner and outer circumferences of the liquid space within the rotor to permit passage of fluid from the feed section of the rotor to the separating section thereof, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

7. In a centrifugal separator, a rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating centrifugal separating operation, said feed secsection adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through the spaces between successive discs, and said separating section being provided with an accelerator for maintaining liquid in said separating section at the speed of rotation of the rotor, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

8. In a centrifugal separator, a rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a tion comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through the spaces between successive discs, and said separating section being provided with a plurality of radially extending accelerator wings, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

9. In a centrifugal separator, a rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid'mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced radially extending discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through the spaces between successive discs, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

10. In a centrifugal separator, a rotor, and means to feed fluid mixture axially to said rotor at approximately the axial center line thereof, said rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly between successive discs, radially extending accelerator wings occupying the space between the outer circumferences of said discs and the inner circumference of the rotor wall and a deflector adapted to cause a fluid mixture fed axially to said rotor to be deflected into the spaces between said discs, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor. 11. In a centrifugal separator, a rotor, and means to feed fluid mixture axially to said rotor at approximately the axial center line thereof,

said rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly between successive discs, radially extending accelerator wings occupying the space between the outer circumferences of said discs and the inner circumference of the rotor wall and a conical deflector adapted to cause a fluid mixture fed axially to said rotor to be deflected into the spaces between said discs, said closely spaced discs being substantially concentric with the axis of the' rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

12. In a centrifugal separator, a rotor, and means to feed fluid mixture axially to said rotor at approximately the axial center line thereof, said rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating section adapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through spaces between successive discs, and a deflector adapted to cause a fluid mixture fed axially to said rotor to be deflected into the spaces between said discs, and a disc overlying said plurality of closely spaced discs for separating the feed section of the rotor fromthe separating section of the rotor, said last-mentioned disc being perforated to permit passage of fluid from the feed section of the rotor to the separating section thereof, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

said mixture to a centrifugal separating operation, said feed section comprising a plurality of closely spaced discs extending outwardly from a central portion of the rotor and mounted forrotation with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through spaces between successive discs, and a conical deflector adapted to cause a fluid mixture fed axially to said rotor to be deflected into the spaces between said discs, and a disc overlying said plurality of closely spaced discs for separating the feed section of the rotor from the separating section of the rotor, said last-mentioned disc being perforated to permit passage of fluid from the feed section of the rotor to the separating section thereof, said closely spaced discs being substantially concentric with the axis of the rotor, substantially parallel to each other and having central feed openings, and the space surrounding said discs lying in the line of liquid flow from the feed section to the separating section of the rotor.

14. In a centrifugal separator, a rotor, and means to feed fluid mixture axially to said rotor at approximately the axial center line thereof, said rotor comprising a preliminary feed section in which liquid under treatment is accelerated and a separating sectionadapted to receive a fluid mixture from said feed section, and subject said mixture to a centrifugal separating operation, said feed section comprising a plurality oi closely spaced discs extending outwardly from a central portion of the rotor and mounted for rotationv with the rotor and adapted to receive fluid fed to the rotor and accelerate said fluid by friction during passage thereof outwardly through spaces between successive discs, a disc overlying said plurality of closely spaced discs for separating the feed section of the rotor from the separating section of the rotor, said lastmentioned disc being perforated to permit passage of fluid from the feed section of the rotor to the separating section thereof, said last-men-

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