US 2695871 A
Description (OCR text may contain errors)
Nov, 30, 1954 .1. sHAvEl., JR., r-:rAL
ROTARY MOLECULAR VACUUM STILL Filed Sept. 25, 1951 United States Patent 1O RQTARY MOLECULAR VACUUM STILL John Shavel, Jr., and Harold E. Zaugg, Waukegan, lll., assgnors -to Abbott Laboratories, North Chicago, Ill., a corporation of Illinois Application September 25, 1951 Serial No. 248,194
4 Claims. (Cl. 202-.205)
This invention relates to improvements in vacuum distillation apparatus, and more particularly to a rotary, molecular still.
Included among the objects and advantages of the present invention is a horizontal still capable of operating under either total reflux or a distilling cycle. The still, furthermore, provides an unobstructed, short-path vapor ilow from the evaporating surface tothe condenser. The molecular still also provides a film evaporating surface thereby greatly increasing vaporizing capacity per unit volume of distilland.
The following description of the preferred embodiment of the invention is to be understood as an illustration and not a limitation thereof.
In the accompanying drawings:
Fig. 1 is a partial vertical section of an improved molecular still embodying the features of the invention; Fig. 2 is a vertical section at right ang-les to Fig. 1, along line 2 2; and, Fig. 3 is a detailed section of a portion of the embodiment of Fig. 1 taken along line 3 3.
Referring to the drawing, a right cylinder 10 of glass construction, having an open end 12 of full diameter and a partial end Wall 14, provides the outer shell or casing of the molecular still. The casing has an evacuation port 16 adjacent the open end, and a ball joint 18 extending outwardly from the partial end Wall. The full diameter opening is closed by a bearing casing 20, which is imperforate, completely sealing the open end of the cylinder. A vaporizing chamber 22 is axially disposed inside the cas-ing. The chamber is a right cylinder of glass having an end wall 24 and a projecting shaft 26 therefrom. In the form illustrated in the drawing the right cylinder 10 has a length of about 270 mm. and an internal diameter of about 80 mm. and the vaporizing chamber 22 has a length of about 155 mm. and an outside diameter of about 70 mm; The open end of the vaporizing chamber has a partial end wall 28 turned inwardly forming a distilland barrier. A double-ball bearing 30 is mounted in the bearing casing, and a drive shaft 32 extends through the bearing. A chuck 34 terminates one end of the shaft and a bar magnet 33 terminates the other end of the shaft. The projecting shaft on the vaporizing chamber is securely held by the chuck. T-he double-ball bearing permits free rotation. A straight tube condenser 40 extends through the ball joint and the partial wall of the vaporizing chamber. The half ball joint 19 on the condenser completes the seal of the end of the cylinder. A receiver 42 communicates with the outer end of the condenser through the passage 44. The condenser is supplied with connections 46 for cool-ing medium.
The vaporizing chamber is rotated by a magnetic drive. The magnetic drive comprises magnet 33 attached to the drive shaft inside the bearing casing. The drive magnet 35 is connected to the shaft of a variable speed motor 37. As the drive magnet 35 rotates, the magnet 33 follows, rotating the vaporizing chamber.
In operation the vaporizing chamber is attached to the chuck and inserted into the cylinder, which is held in substantially horizontal position. The connection between the bearing casing and the still casing is sealed by stopcock grease or a gasket. The condenser is placed inside the vaporizing chamber and rotated slightly to securely seat the ball joint. The condenser is connected to the cooling medium supply, and the distillate receiver is put in place. The condenser is moved to a position so ice that the inner end Lis slightly below horizontal, which is the total redux position. The ball joint permits sutilcient movement of the condenser for various distilling operations. During distillation the still should be substantially horizontal, so that the distilland is vevenly spread in bottom of vaporizing chamber. The vaporizing Vchamber is rotated at the desired speed by controlling lthe drive motor. As the chamber is rotated, the dis- .tilland -wets the chamber wall, and .a thin tlm adheres to the Wall. The film substantially coats the 'entire wall, yexposing a large surface area for evaporation.
In the embodiment of :the invention described, vaporizing heat is supplied lby .an infrared lamp 48, but any means of radiant heating is satisfactory. After operating under `total reux conditions until equilibrium is obtained, the condenser is .then moved to a position where the inner end is above horizontal. In this position the condensate tlows along the condenser and subsequently into the receiver.
The still is normally operated under vacuum, and the evacuat-ing port should be large enough to prevent a back pressure build up from the high rate of evacua-tion caused by the large lm area. The position of the condenser inside the vaporizing chamber aids in preventing vapor pressure build up, and hence, the pressure inside the vaporizing chamber is substantially the same as in the casing. The lack of packing gl-ands, also, greatly aids in maintaining the desired vacuum, so that only a small pump is required to remove the non-condensable gases.
The construction of the still makes a very short path vapor ow from the evaporating surface to the condensing surface. The vapor path is, furthermore, a straight line unobstructed flow, increasing eiiciency and decreasing both back pressure and vapor hold up.
In the embodiment illustrated, the still is for batch 0peration. However, by adding a feed tube and a residue withdrawal tube into the vaporizing chamber, the still f will operate continuously.
Others may readily adapt the invention for use under various conditions of service, by employing one or more of the novel features disclosed or equivalents thereof. As at present advised with respect to the apparent scope of our invention, we desire to claim the following subject matter.
1. Vacuum distillation apparatus comprising, a cylinder, evacuating means for said cylinder, closure means abutting one end of said cylinder, a vaporizing chamber axially disposed in said cylinder, condenser means closing the other end of said cylinder and extending into said chamber, the inner end of said condenser being movable with respect to the axis of the vaporizing chamber, said chamber rotatably connected to said closure means, means for rotating said chamber, and radiant heating means externally disposed on said cylinder.
2. Vacuum distillation apparatus, comprising, a cylinder having a full diameter opening at one end thereof, -a vaporizing chamber axially disposed in said cylinder, an imperforate bearing casing closing said full diameter opening, condenser means closing the other end of said cylinder and extending into said chamber, the inner end of said condenser being movable with respect to the axis of the vaporizing chamber whereby the rate of collecting the distillate is variable means for evacuating said cylinder, distillate receiving means communicating with said condenser, said chamber having one end wall with an axial projection thereon and a partial end wall at the other end thereof, bearing means in said casing rotatably holding said chamber, means for rotating said chamber, :tilnd external radiant heating means supplying vaporizing eat.
3. Vacuum distilla-tion apparatus comprising, a cylinder having a full diameter opening, evacuating means for said cylinder, an axially disposed cyl-indrical distillation chamber in said cylinder, an imperfor-ate bearing casing closing said open end of said cylinder, movable condenser means closing the other end of said cylinder and partially extending into said chamber, a distillate receiver communicating with said condenser, said chamber having an end wall and a projection thereon, a bearing disposed in said casing, a chuck mounted on said bearchamber in rotatable position in said cylinder, means 1n the nature of a pair of magnets for rotating said chamber, one of said magnets disposed externally of said casing yand attached to a drive motor, the other said magnet internally disposed in said casing and attached to said chuck, the inner end of said condenser movable above horizontal for collecting distillate and below horizontal for total reux, and external radiant heating means for supplying heat to said chamber.
4. Vacuum distillation apparatus comprising, a generally horizontally disposed cylinder having one full diametcr open end, a concentric distillate chamber having one partially open end rotatably mounted in said cylinder,
imperforate closure means sealing said full diameter open 15 ing, movable condenser means closing the other end of said cylinder and extending into said cylinder, evacuating means for said cylinder, receiver means communicating with said condenser, means for rotating said chamber, and
external means for supplying vaporizing heat, said condenser adapted to be moved with the internal end below Ihorizont-al position for total reflux and above horizontal position for distillation.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 10 2,129,596 Waterman et al Sept, 6, 1938 2,526,676 Lovet-t Oct. 24, 1950 2,538,967 Hickman Jan. 23, 1951 2,554,703 Hickman May 29, 1951 FOREIGN PATENTS Number Country Date 718,347 Germany Mar. 10, 1942 614,388 Great Britain Dec. 15, 1948