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Publication numberUS2784150 A
Publication typeGrant
Publication dateMar 5, 1957
Filing dateSep 16, 1953
Priority dateSep 16, 1953
Publication numberUS 2784150 A, US 2784150A, US-A-2784150, US2784150 A, US2784150A
InventorsArthur Rose, Sanders William W
Original AssigneeArthur Rose, Sanders William W
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Agitator for vacuum still
US 2784150 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)


INVENTORS ARTHUR ROSE WILLIAM W. SANDERS ATTORNEY United States Patent AGITATOR FOR VACUUM STILL Arthur Rose and William W. Sanders, State College, Pa., assignors to the United States of America as represented -by the Secretary of Agriculture "Application september 16, 195s, serial No. 380,627

z claim.- (ci. 2oz-17s) This invention relates to means for the agitation of the liquid phase in the boiler of a still adapted for operation at subatmospheric pressure,

i An object of thisninvention isto provide an improved agitator Yfor usein vacuum stills. Another object is to provide means `for preventing bumping 'of the' liquid in the boiler of vacuum stills. A further object is to promote quiet, steady equilibrium evaporation from the liquid phase in the boiler of vacuum stills. A still further object is to provide an agitator which is entirely 'sealed within the apparatus but which may be operated by means of external energy sources.

The term bumping as understood in the art, means the sudden, violent, irregular evolution of vapor from a hot liquid. Bumping may be encountered in the boiling of any liquid and is particularly troublesome in the distillation of viscous, high-boiling substances, especially if the distillation is carried out under vacuum. Bumping is espe'- cially objectionable in fractional distillations in vacuum because the sudden irregular surges of super-heated vapor evolved from the boiler upset the vapor-liquid equilibrium in the fractionating column and hence impair the efliciency of the fractionation.

To prevent the foregoing ditiiculties, we Ihave invented the agitator described below for use in vacuum distillations which is effective at all pressure-s and with liquids of high viscosity, which requires no sealing gasket, packing, or lubricant, and which can be constructed entirely of noncorroding material. The agitator is actuated by an cxternal solenoid, thus dispensing with the need for packing glands, seals, bearings, or lubricants.

A preferred embodiment of our novel agitator is described in the following specification, reference being made to the accompanying drawings. Similar reference numerals refer to like parts in the several views.

In the drawings:

Figure 1 shows a vertical section through a ycomplete assembly of a still boiler Iand includes the details of our novel agitator unit.

Figure 2 is a plan view of one of the agitator baies.

In a preferred embodiment of our invention, the agitator comprises a solid glass rod or shaft 1 having a plurality of cup shaped -batlies 2 attached at intervals along its length. These bafles are arranged with their concave sides down and are provided with a number of holes 3 around their surfaces. Fused to the upper end of rod 1 is a length of glass tubing 4 in which is sealed a soft iron armature 5. At the lower end of the solid glass rod there is fused another length of glass tubing 6, around" which iswound a bumper spring 7, which is made of a non-corroding material, such as, stainless steel wire. In order to secure the spring to the stirrer, 'both ends of the wire are passed through a hole 8 in the tube 6, and several turns taken around the tube. The baflies are secured to the glass rod by fusing short pieces of rod to the s, and then fusing the ends of these short rods together toa continuous length. i

2,784,150 Patented Mar. 5, 1.957

In use, the stirrer is mounted vertically in a still pot 9, as shown in Figure 1, of such size that the liquid level 10 in the pot fallson that part of the rod4 or shaft 1 on which the batlies are disposed when the spring bumper 7 rests on the bottom of the pot. The boiler is provided with two necks 11 and 12, each having a spherical ground joint 13 and 14, respectively, at its end. Neck 12 is connected' to tube 15, the lowe'r'end of which'is ground to mate with joint 14, and the upper end of which is sealed. `A glass wool pad 16 is inserted and secured in the upperend of tube 15. To the other neck 11 there is attached another tube 17 which conducts the distilled vapors to a condenserl or a fractonating column, not shown. Both spherical joints 13 and 14 are held together by means of conven-I tional clamps, not shown, available for thepurpose To operate the stirrer'a' solenoid 18 is placed around the upperend of tube 15, andso adjustedin position that, when intermittently "energized, it will alternately `liftjand drop the stirrer by means of the soft iron armature 5 with' a vertical reciprocating motion.l This-'motion should liar/"ev suflicient amplitude to assure that at least one of tlige baffles on the stirrer shaft passes through the liquid surface. Oni the upstroke this breaks the surface and splashes the liquid, and also exerts a pumping action whereby circulation within the body of liquid is favored. On the downstroke the bal-e or baies that pass through the liquid surface not only exert a splashing and pumping effect, vbut also carry trapped vapor below the surface. This vapor gradually escapes as a train of,bubbles from the perforatioi'is in the baie. These bubbles act as nuclei for evolution of vapor from the boiling liquidr and thus help avoid superheating and bumping. Y v

The time cycle during which the solenoid is energized and de-energized, andjduring which the stirrer makes one upward and one downward stroke, may be variedfwidely, 'but we have found that a frequency of from 501to 150 cycles per minute gives best results with most liquids. 1t is apparent that, if the frequency is too low, there will be superheating and bumping of the liquid between strokes ot' the stirrer. On the other hand, if the frequency is too high, the stirrer will not have time to make a fullstroke and will vibrate with `too small an amplitude. Thus, the optimum frequency will depend upon the -size of the apparatus, the depthand viscosity of the liquid, and the rate of distillation; but it is easily determined in practice.

The purpose of the spring bumper on the lower end of our stirrer and the glass wool fabric above the upper end l is to cushion the strokes of the stirrer and preventbreakage where the stirreror the still pot, or both, are made of glass. It will be apparent, however, that our invention is not limited to the use of glass apparatus but any of the structural materials commonly used in industry may be substituted; nor is it necessary to use spherical joints. Any joint capable of holding a vacuum or high pressure may be used instead. lf neither the'stirrer nor the still pot is made of glass then the glass fabric pad and spring may be dispensed with; although the spring bumper also has some advantageous effect in that its resiliency helps start the stirrer on its upward stroke and thus promotes smooth operation. If the time cycle on which the stirrer is actuated corresponds to the natural frequency of the. spring as loaded, a harmonic oscillation of the stirrer is set vup and operation of the assembly is particularly smooth and efficient.

Any conventional timer having a suit-able on-of cycle may be used in the solenoid circuit, although in the interest of adaptability it is highly desirable that its time cycle be adjustable.

We claim:

1. A vacuum still' capable of equilibrium evaporation with no bumping comprising a still pot having two necks, one of said necks being connected to a longitudinally ex- 'tended mee losen .ai as .fsf end, :he seem: @issie seeks being connected to condensing means; the Yfirst of said necks and its attached tube having extending therein an agitator comprising an elongated shaft having disposed along its midsection in a .spaced relationship .-a plurality of inverted cup-shaped bailles, each baffle having n plurality of perforations spacedly -disposed,over it-ssurface, ,said shaft passing through `the center of, and being rigidly attached to, :each baille, `said shaft further having att-ached to its lower end 'an open-spiral elastic spring and to its upper end a totally enclosed chamber containing a soft iron core; the aforementioned tube attached to the first neck Ibeing surrounded near vits upper end by a solenoid capable of imparting a vertically reciprocating motion Vto the enclosed agitator when `said solenoid is cyclical'ly activated and `deactivated by passage of electric current therethrough.

2. A vacuum still capable of equilibrium evaporation with no bumping comprising a still pot having two necks, one of said necks lbeing connected to condensing means; the second of said necks having an upwardly vextending tube attached thereto, said tube being sealed at its upper end and having disposed therein an agitator comprising ,an elongated shaft extending substantially to the bottom of the still pot, a plurality of cupshaped -baies rigidly `attached to the shaft in spaced relationship to each other with their open concave sides downward, the shaft passing jtlrrotfighthe center-1 of each nfiasiaidlbatiies, eachbattle having disposed over its surface a plurality of small perforations, an'elastic Vspring secured to the lower end of the shaft, and means to impart to said shaft a reciprocating motion parallel to the long axis of the shaft.

References Cited in the le of this patent UNITED STATES PATENTS 6,133 Y Murdock Feb. 20, 1849 99,883 Haines Feb. .15, 1870 s 1,176,953 Fritz Mar. 28, 1916 A1,745,177 Markley Jan. 28, 1'9'30 1,962,275 v Holst et al June 12, 1934 2,128,544 mrianino Ang.`30, V1938 2,142,961 Kuhn l Jan. 3, 1939 2,149,987 Altorfer" Mar. 7, 1939 2,235,094 Walker Mar. 18, 1941 2,242,812 Brown May 20, 1941 2,356,573 `'Dunham Aug. 22, 1944 '2,425,691 Brewer Aug. 112, 1947 2,471,876 Kuhn May 31,' 1949 2,498,212 Laverell et al. Feb. .21, 1950 2,635,949 Fenske et al Apr. '21, 1953 2,661,938 Knentzei Dec; 8, 1953

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Referenced by
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US3158294 *Feb 5, 1959Nov 24, 1964Handlee James CMaterial conveying apparatus for bins
US3206172 *Aug 5, 1963Sep 14, 1965Dow Chemical CoApparatus for use in procedures requiring agitation in a closed system
US3306829 *Apr 27, 1966Feb 28, 1967Arthur H Thomas CompanyMagnetic stirrer in a still
US3532325 *Jul 23, 1968Oct 6, 1970Barnett Jackson Herman JrMethod and apparatus for generating shock waves
US3676983 *Feb 14, 1971Jul 18, 1972Walter E NoldApparatus and method for degassing a liquid
US4279704 *Aug 8, 1980Jul 21, 1981Noble Sr Kenneth EDry cleaning still apparatus
US5164049 *Aug 22, 1990Nov 17, 1992Athens CorporationMethod for making ultrapure sulfuric acid
US5354428 *Jul 25, 1989Oct 11, 1994Athens Corp.Apparatus for the continuous on-site chemical reprocessing of ultrapure liquids
US6322056Sep 26, 2000Nov 27, 2001Gerhardt Van DrieSubmarine type liquid mixer with aeration
US6554259Mar 2, 2001Apr 29, 2003Gerhardt Van DrieHigh dissolved oxygen mixer-digester
US6599426Jun 26, 2002Jul 29, 2003Gerhardt Van DrieHigh dissolved oxygen mixer-digester method
US6814344Nov 22, 2002Nov 9, 2004Nesson EnterprisesMethod and apparatus for circulating fluids in a body of liquid
US6926437Sep 10, 2003Aug 9, 2005Gerhardt Van DrieGravity powered mixer system
US8133386 *Mar 24, 2011Mar 13, 2012Gerhardt Van DrieBiological waste digester and method of operation
US20040052157 *Sep 10, 2003Mar 18, 2004Drie Gerhardt VanGravity powered mixer system
US20040099315 *Nov 22, 2002May 27, 2004Peterson Francis C.Method and apparatus for circulating fluids in a body of liquid
US20090034358 *Feb 12, 2007Feb 5, 2009Bayer Technology Services GmbhMethod and Apparatus for the Gassing and Degassing of Liquids, Particularly in Biotechnology, and Specifically of Cell Cultures
U.S. Classification202/175, 366/332, 366/256, 366/117, 366/242, 202/265
International ClassificationB01D3/14, B01D3/32
Cooperative ClassificationB01D3/32
European ClassificationB01D3/32