US2431142A - Centrifugal separator with means for controlling discharge therefrom - Google Patents

Description

NOV. 18 1947. UT I I 2,431,142

CENTRIFUGAL SEPARATOR WITH MEANS FOR CONTROLLING DISCHARGE THEREFROM v Filed Aug 18, 1943 2 Sheets-Sheet 1 INVENTOR flagwjflenq'y 6212142512 BY Cr: 2

GENT

Nov. 18,- 1947. A, H, SCHUTTE 2,431,142

CENTRIFUGAL SEPARATOR WITH MEANS FOR CONTROLLING DISCHARGE THEREFROM Filed Aug. 18, 1943 2 Sheets-Sheet? "III Patented Nov. 18, 1947 CENTRIFUGAL SEPARATOR WITH MEANS FOR CONTROLLING DISCHARGE THERE- FROM August Henry Schutte, Hastings on Hudson, N. Y. pp ic i n A u t 18, 1943, Serial No. 99.059

(Cl. 233ml?) 3 Claims. 1

This invention relates to improved centrifugal apparatus for continuously separating mixtures of liquids and solid and more particularly to centrifugal apparatus for separating the liquid and solid constituents of an emulsion of a waxy oil or an oily wax of the general type disclosed and claimed in my prior patent, No. 2,168,306, issued August 1, 1939.

In this prior patent, there are described the difiilculties encountered in separating the wax and the oil contained in an oil-wax mixture such as a wax-bearing mineral oil or a slack wax and the novel manner in which this problem has been solved whereby low pour point lubricating oil and commercial scale wax may respectively be elfeetively separated from an emulsion formed of such an oil-wax mixture. As disclosed in this prior patent, the oil-wax mixture is emulsified in liquid condition with a non-solvent, non-reactive liquid such as water and an inert, non-solvent gas such as air to produce a dispersed phase of the oil-.wax mixture in the non-solvent, non-reactive liquid. The resulting emulsion is chilled or cooled down below the melting piont of the wax to solidify the desired wax fraction, and thereafter the partially solidified emulsion is desirably subjected to centrifugal force to separate the solidified wax from the remaining liquid constituents.

The present invention is an improvement over this basic concept as disclosed and claimed in my prior patent and is particularly directed to an im proved solid bowl centrifugal apparatus for securing an accelerated settling or separation of the liquid and the solid portions of the emulsion.

An. important object of the invention is to provide a centrifugal separating apparatus including improved means for controlling discharge of components of a mixture separated thereby.

Other objects of the invention will appear hereinafter.

In the accompanying drawings I have disclosed a preferred embodiment of the invention wherein the separation is accomplished in a time cycle synchronized with the continuous feed of emulsion into the centrifuge t create an automatic discharge of the separated components of the emulsion throughout the operation of the apparatus. In these drawings:

Fig. 1 is a vertical sectional view through the centrifuge showing the relationship of the rotating solid bowl, the feed distributing bafile, and the inner solid wall spaced from the rotating bowl;

Fig. 2 is a plan view of the apparatus, partly broken away to disclose the bowl wall structure and automatically operated skimmer;

Fig. 3 is a view, similar to Fig. 2, of a modified form of manually operated liquid skimmer;

Figs. 4, 5, 6, and 7 are diagrammatic views illus- 2 tratlng the respective positions of the separated liquids and solids during the cycle of operation of the apparatus.

While the present improved apparatus is applicable to the separation of a partially solidified emulsion of a mixture of any two or more components having the requisite operating characteristics, it is particularly useful in the emulsion dewaxing or deoiling of an oil-wax mixture. The non-solvent, non-reactive liquid such as water should have such a density that, when it is mixed with the remaining liquid oil, the resulting liquid mixture is heavier than the separated solid wax,

Numeral I indicates a fixed, double wall outer casing including a centrally apertured end wall 3 and a cover 5 having a central opening I through which the drive shaft 9 and the feed pipe I I pass. The drive shaft 9 is secured to the inner end partition I3 of a solid wall, rotatable, outer centrifugal bowl I5. This end partition I3 and the inner solid cylindrical wall H, with which it is desirably made integral, are spaced from the end wall I9 and the cylindrical wall 20 of bowl I5, respectively, in fixed relation thereto by the radial web portions 2i extending from the periphery of the partition I3 to the cylindrical wall of the bowl. At the opposite end of the bowl I5, there is provided an inwardly directed annular lip 23 having an inner edge 25 defining an opening of smaller diameter than that of the inner cylindrical wall H, which terminates slightly short of the full diameter portion of the outer bowl I5. The inner cylindrical wall I1 and the partition l3 together form an inner solid-wall bowl in spaced nested relation to the outer bowl I5. The spaced ends I3 and I9 of the two bowls define a collecting channel for liquid, and the spaced cylindrical walls I1 and not the two bowls define an eduction channel for leading liquid from the open end of the inner bowl to the said collecting channel.

In accordance with the invention, the feed pipe II terminates intermediate the end partition I3 and an annular feed distributing baflle 21, which is secured in spaced parallel relation to the end partition. The discharge end of pipe I l is turned outwardly as shown at 28 so that the incoming emulsion is directed radially outwardly toward the inner wall W.- This feed bafile 27 has a somewhat smaller diameter than the end partition I3 whereby an annular passage 29 is formed between the periphery of the baflle 21 and the inner surface of the cylindrical wall I1. Desirably, the outer diameter of bafile 21 is greater than the inner diameter of annular lip 23.

The fixed, double wall outer casing I may be divided into temperature controlling compartments 3| and 33 by a partition 35 having an inner circumferential extension 3'1 carrying a right.-

angled cylindrical flange 39 lying in spaced parallel relation to thecylindrical wall 20 of the ro-- tating separator bowl l and terminating approximately at the beginning of the inturned lip portion 23 thereof. Partition 3'! and flange 39 form a collecting channel into which the separated solids are discharged. Tempering liquids to maintain the desired temperature control may be circulated through compartments 3| and 33 by suitable conduits (not shown) According to the invention, an angled liquid skimmer pipe 4| is pivotally mounted in a bracket 43 supported on flange 45 formed in the apertured end wall 3 of the outer fixed casing The offset scoop portion M of the liquid skimmer 4| passes through the apertured end wall IQ of the rotatable separator bowl l5 and lies in intermediate spaced parallel relation between the end wall l9 and the inner end partition l3. The relative position of the scoop end 4'! of the skimmer pipe 4| with relation to the cylindrical wall 29 of the bowl 155 is adjusted periodically by means of a time or cake level-controlled motor 49 having a reciprocable element 5| pivotally secured to the pivoted skimmer pipe 4| by a link 53. Any suitable power means or motor may be employed to reciprocate the element 5|. A pneumatic motor is indicated at 49. Such a motor has a diaphragm to which the element 5| is secured. Admission of air under pressure to one side of the diaphragm causes same to fiex and thrust the element 5| in one direction and release of air pressure upon the diaphragm permits a spring to flex the diaphragm in the opposite direction and retract the element 5|. A time control means may be employed to control admission of air to the diaphragm and exhaust therefrom, for a purpose which will be explained hereinafter. This type of pneumatic device is quite common and, since the construction of the device 49 per se forms no part of the present invention, only the exterior of the device is shown. As shown in Fig. 3, the position of the skimmer pipe may also be set by a manually operable hand wheel 55 and the worm- gear arrangement 51, 59.

The cycle of operation of the machine is clearly shown in the fragmental detail drawings, Figs. 4 to 7 inclusive. These figures illustrate the several positions of the skimmer pipe 4| with relation to the annular layers of materials separated from the emulsion fed into the machine through the feed line I. Fig, 4 illustrates the initial operating position of the skimmer where the space between the wall 20 of bowl l5 and the inner wall I1 is being filled with separated liquid and where separated liquid and separated solid are filling the annular space from the inner wall H to the inner edge 25 of the annular lip 23. The partially solidified emulsion of an oil-wax mixture, for example, introduced through the pipe under the baffie 2'! is discharged radially outwardly toward the inner wall I! and thereafter flows along this inner wall through the annular passage 29. Due to the centrifugal force exerted by the rotation of the outer bowl and spaced solid inner Wall, the relatively heavy non-solvent, non-reactive, liquid such as water separates from the emulsion and flows outwardly over the upper edge of the wall I! and fill the space between the outer rotary bowl I5 and the inner cylinder I? as indicated by the letter L in Figs. 4 to '7 inclusive. The somewhat lighter oil also separates from the emulsion and extends in an annular layer 0 from the baflle 21 to the lip 23 in parallel relation to the liquid layer L. The relatively light separated wax W, which has a substantial porosity resulting from the emulsification step, floats on the intermediate oil layer 0 and also extends in an annular layer from the feed bafile 2'! to the inturned lip 23 of the bowl l5. That part of the wax which is above the oil level is substantially dry, and that part of the wax which is submerged in the oil layer is, of course, wet with oil.

When the initial operation has continued until the inner surface of the wax layer W approaches the inner edge of the lip 23 as indicated in Fig. 4, motor 49 is energized to move the scoop portion 41 of the skimmer pipe 4| radially outwardly toward the wall 29 of bowl I 5, whereby the water or non-solvent liquid L and the oil 0 are partially removed from the apparatus through the annular liquid leg between walls I1 and 20 as shown in Fig. 5, the oil layer being renewed as the separation continues. The motor 49 actuating the skimmer pipe may be energized by a time control 60 (conventionally shown) or by a suitable controller which operates whenever the cake level in the bowl is built up to a predetermined level or thickness. The effect of this liquid removal is to cause the wax layer to move radially outwardly into the position shown in Fig.: 5. During this portion of the cycle, the emulsion is continuously fed into the centrifugal separator through line Following this step, the skimmer pipe is withdrawn from contact with the separated liquid in the skimming channel between end partition [3 and the end wall I!) whereupon the continued feed of emulsion causes a build-up of the separated layers L and O. The wax layer W floating thereon is thus radially and inwardly displaced until it reaches the inner edge 25 of the lip 23 as shown in Fig. 6. The position of the several annular layers at this point is substantially the same as that shown in Fig. 4 for the initial starting operation. Thereafter, the continuation of the feed causes a further inward displacement of the wax layer and its resultant discharge over the lip 23 into the stationary wax collection channel as shown in Fig. '7.

When a sufficient amount of the driest portion of the wax layer has been discharged in this fashion, motor 49 is again energized to cause the scoop 41 to engage the liquid in the skimming channel for removal of a further portion of the oil and heavy non-solvent liquid. At this period of the cycle the position of the layers in the bowl is again that shown in Fig. 5, and the cycle is complete. A repetition of this operating cycle with a continuous feed results in a periodic removal of the separated liquid constituents and of the dry buoyant solids. The displacement and discharge of the wax inwardly over the lip of the bowl are done by the pumping action of the rotating bowl, which is applied to the annular wax mass radially and inwardly.

The displaced wax is discharged into the annular circumferential collection channel formed by partition 3'! and baflle 39 and is removed therefrom through outlet 6|. The upper compartment 33 may be maintained at a temperature sufficient to melt the discharged wax so that it freely flows through the outlet SI, and the lower chamber 3| may be maintained at the temperature necessary to insure the desired separation of the partially solidified emulsion.

If the solid portion of the emulsion undergoing separation has such a nature that it can withstand axial displacement without undue compacting or loss in porosity, the cyclic operation heretofore described becomes unnecessary; and the scoop 41 may be set in one position for continuous removal of the liquid constituents therethrough and for continuous discharge of the solid constituents over the lip 23. In this case the device resolves itself into the form shown in Fig. 3. Here, the position of the scoop 41 may be regulated or set by a hand whee] 55 attached to a rod carrying a worm 51 meshing with a pinion 59 secured to the skimmer pipe 4|.

The feed distributin baffle 21 is important to the successful operation of the present improved centrifugal separator, for it cause the continuous feed of partially solidified emulsion to reach the inner wall I! through the annular passage 29 before any separation of the liquid and the solid constituents of the emulsion takes place. Desirably, the outer diameter of bafiie 21 is such that the feed is caused to discharge into the liquid layers along wall 11. In this manner, there is no possibility for the collapse of oil-soaked wax with the resultant interruption of operations.

It is to be understood that my improved apparatus is applicable not only to the separation of oil-wax emulsions but also to the separation of an emulsion of any mixture of materials having the requisite characteristics of light solid and heavy liquid.

Although a preferred embodiment of my inven tion has been described, modifications thereof will be apparent to those skilled in the art; therefore, only those limitations appearing in the claims appended hereinafter should be applied.

I claim:

1. A centrifugal separating apparatus including a rotor comprising an outer solid-wall bowl open at one end and having an opposite end wall, a charge-receiving inner solid-wall bowl in concentric nested relation to the outer bowl and open at the end thereof adjacent the open end of the outer wall and having an opposite end wall in opposed spaced relation to said end wall of the outer bowl, the bowls defining an annular liquideduction channel between their said side walls and an annular liquid-collecting channel between the opposed end walls said collecting channel being open at the side thereof nearest the axis of the rotor, the outer bowl having an annular lip at its open end extending radially inward past the edge of the open end of the inner bowl, and a fiow communication between the open end of the inner bowl and the adjacent end of the eductionchannel for discharge of a separated heavy liquid component of the mixture into the eduction channel, the latter extending from said lip to the collecting channel and opening thereinto at a point spaced radially outward from said open side of the collecting channel; means to withdraw liquid from the collecting channel during rotation of the rotor; and means rendering said withdrawing means adjustable to reduce the radial depth of liquid in the collecting channel in one adjustment and permit flow of the liquid from the inner bowl to the eduction channel and, in another adjustment, permit an increase in said depth to cause an accumulation of the liquid Within the eduction channel to obstruct flow thereto from the inner bowl and thereby cause accumulation of liquid within the latter to displace a separated lighter component of the mixture radially inward for axial discharge thereof past said lip.

2. A centrifugal separating apparatus comprising a rotor including a bowl to receive a mixture for separation, said bowl being open at one end and closed at its opposite end, an annular liquidcollecting channel at one end of the bowl concentric with the axis of the rotor and open toward said axis, a flow communication between the bowl and said channel, said bowl, channel and communication being correlated for delivery, during rotation of the rotor, of a separated heavy liquid component of the mixture from the bowl through the communication to the channel at a point spaced radially outward from the open inner side of the channel, and lip means constructed and arranged to prevent axial discharge of a separated lighter component of the mixture through the open end of the bowl for a predetermined distance radially inward from the circumferential wall of the bowl said liquid-collecting channel extendin depthwise radially nearer to the axi than said lip means; scoop means to withdraw liquid from said channel during rotation of the rotor; means supporting said scoop means independently of the rotor for adjustment radially of the channel to reduce the radial depth of the liquid within the channel in a radial outward adjustment of the scoop means and thereby permit said liquid delivery to the channel and, in a radial inward adjustment of the scoop means, permit an increase in said depth to oppose said delivery and thereby cause an accumulation of the liquid within the bowl to displace said lighter component radially inward to a position for discharge past said lip means; power means operatively associated with the scoop means for said adjustments thereof; and timer means operatively associated with said power means for control thereof to cause said adjustments of the scoop means periodically in alternation.

3. A centrifugal separating apparatus as defined in claim 2, wherein the liquid-collecting channel is located at the outer side of the closed end of said how], wherein the apparatus includes means for introducing the mixture continuously into the closed-end portion of the bowl, and wherein said flow communication between the bowl and the liquid-collecting channel comprises a conduit extending from the open end portion of the bowl to the collecting channel.

AUGUST HENRY SCHUTTE.

REFERENCES CITED The following references are of record in the Number Name Date 347,702 Evans Aug. 17, 1886 473,322 Laidlaw Apr. 19, 1892 827,263 Patterson July 31, 1906 957,478 Simpson May 10, 1910 1,053,785 Cave Feb. 18, 1913 1,119,176 Kopke Dec. 1, 1914 1,350,009 Del Valle Aug. 17, 1920 1,736,792 Lundgren Nov. 26, 1929 1,967,032 Lindberg July 17, 1934 2,165,807 Murphree et a1 July 11, 1939 2,244,034 Van Riel June 3, 1941 FOREIGN PATENTS Number Country Date 487,249 Great Britain June 16, 1938 162,276 Germany July 26, 1905 335,002 Germany Mar. 24, 1921 Certificate of Correction Patent No. 2,431,142. November 18, 1947. AUGUST HENRY SOHUTTE It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 5, line 45, claim 1, for said read circumferential; line 47, same claim, for the read their said; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 3rd day of February, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

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