US2324195A

US2324195A - Apparatus for treating chemicals

Info

Publication number: US2324195A
Application number: US351020A
Authority: US
Inventors: Walter A Carlson; Paul W Salo
Original assignee: General Mills Inc
Current assignee: General Mills Inc
Priority date: 1940-08-03
Filing date: 1940-08-03
Publication date: 1943-07-13
Anticipated expiration: 1960-07-13

Description

July 13, 1943. w. A. CARLSON ETAL APPARATUS FOR TREATING CHEMICALS jjvenzozu JcVaZZer A. on,

Carla Filed Aug. 3, 1940 d M 13,1943 Y 2,324,195

UNITED STATES PATENT OFFICE 2,324,195 APPARATUS FOR TREATING CHEMICALS Walter A. Carlson and Paul W. Salo, Minneapolis, Minn, assignors to General Mills, Inc., a corporation oi Delaware Application August 3,1940, Serial No. 351,0zo

. 6 Claims. (Cl. 23-267) V This invention relates to apparatus for treatare substantially all retained by the cloth and ing chemicals and more particularly to apparathe'screen. ,n.

tus for rapidly dissolving a chemical to be purl- The upper end of the rod connects through a iled in a hot solvent, recovering the volatilized suitable connecting rod 28 with a crank pin 26 on solvent and recrystallizing under conditions oi j controlled cooling.

a plate 21 which is rotated at a suitable speed v through a reduction gearing, not shown, by An object 01' the invention is to provide a simmeans of a motor 28.

ple and eflicient apparatus of this type for the Thus the container secured to the bottom 01" purification of crystalline chemicals and for the the rod II acts as an agitator when moved up recovery of their solvents. and down by the connecting rod 25 and greatly Another object is the provision of a process for increases the rate of solution of the chemical A dissolvinga chemical and for recovering the same in the solvent B in the kettle. This solvent is in crystalline form under conditions which first purposely kept well below the top 01' the kettle cause rapid solution without the application of so as to'leave a clear space 30 into which the sumcient heat to injure delicate chemicals, such filter member can be raisedas shown in dotted .as those containing pro-vitamins like ergosterol, lines. A suitable chain and hook 3i are pro and then bringing about recrystallization of that videdfor fastening the'rod in the elevated posichemical in the same apparatus under the most -tion so asto permit the filter 20 to be raised favorable conditions. to the dotted position in which the residual sol- These and other objects as will hereinafter 20 vent may drain therefrom. appear are accomplished in this invention which A pipe sit-supplied with a valve 34 connects is fully described inthe following specification with the. bottom of the jacket II and serves as and shown inthe accompanying drawing in -a drain. The jacket also connects through a which horizontal pipe 35 with a vertical pipe 38 which Figure l is a vertical section through the 'apin turn connects through a valve 31, a cylinder paratus; I l8 and a pipe 39 with the top of the Jacket. An Fig. 2 is a partial end elevation oi the motor for expansion tank .40 connects through a pipe 4i agitating; v with the top of the jacket and has an overflow Fig. 3 is a perspective view of a perforated conpipe 42. A pipe 43' having a valve 44 leads down ,tainer for holding the materialt'obe treated; from the pipe and connects with the water Fig. 4 is a partial enlarged section on the line supply. A coil 45 is located in the cylinder II 4 of Fig. ii; and I and has pipes 46,41 by means 01 which hot or is it 17 enlarged perspective View cold liquids or steam may be circulated through 322 g g sg i fig gg gg a otb Q t d the coil fcgr heating or cooling the water in the cylinder 3 A pipe 48 controlled by a valve 48 vemlgodiment illustrated comprises kettle is connected to a suitable source of steam and g ifg i $2 1 3: 2 522 gz gt fifiz is provided with an injector 50 for heating Jacket ii surrounded by a heat insulating jacket fi ggg i gignzzgfig ggd 12 3x63 duii gg l2 and provided with a heat insulated cover i3 the heating cycle. which is secured thereto as by means of bolts l4. a

A rod i5 preferably extends through the cover gg g g g zg gi gg ffi fiig s and is provided with a suitable packing gland ii. y a y This rod carries series of arms terminating valve it, one side 01' th valve connecting through in anus m A fine wire screen '9 is soldered a pipe," with a receiver 58 and the bottom to to this ring so as to completely close the same is provided vent and prevent the passage or the material to be 88'. For convenience, a thermometer 59 isprotreated past the screen. A cloth cover 20 de- 9 887mm the temperature M the jacket pends from the ring it to which it is secured by H d a th m the temperature means oi a band II, the ends of which are- 9 the q t drawn together by any suitable form of clamp Y A e-5 leads r the space 30 above the '22. The mat rial A t be t e 1 m with; liquid in the kettle to a condenser 60 and thence this cloth which serves as both a containerand through a. sight box 61 to a re eiver Bl which is a filter since the material to be dissolved and provided witha vent. 88.. A coil 89 in th cylrecrystallized often contains impurities. These 66 Rider 4 is supplied with cold water through a pipe Ill, the water being carried to a drain through a pipe 'H.

Thus it will be" seen that the solvent B in the kettle vaporizes and passes over through the cooling coil 89 where it is condensed and passes into the receiver as as recovered solvent C. This receiver is drained by means of a pipe 15 which connects through a valve with a hand pump 11 the delivery side of which connects through a pipe 18 with a pipe 35. The intake of the pump 11 also connects through a valve 19 and a pipe 80 with the bottom of the receiver 58. The receiver 58 may also be drained by means of a valve 8!, and the receiver as may be drained by a valve .2.

Thus the recovered and purified solvent C in the'receiver 68 may be returnedto the kettle by opening the valve 18 while the valve 19 remains closed. On the other hand, the liquid D in the receiver 58 is the unvaporized residue which has been drained from the kettle and this may be returned to the kettle if desired by opening the valve 19 while the valve It remains closed by the operation of the pump 11.

It will be apparent that by means of the kettle and its associated parts; the operator has a piece of apparatus by which he can perform a multiplicity of operations and control the speed of those operations to a very high degree.

Thus he takes a material like ergosterol which contains impurities and places them within. the filter bag at the bottom of the agitator. He then tightly clamps the cover on the kettle and heats the water within the jacket Ii by means of steam from the pipe 48 and proceeds to agitate the filter assembly 20 in the solvent B. During this operation some of the solvent may boil of! in which case it is cooled by the coil 69 and falls into the receiver 68. This operation then continues until the ergosterol or other chemical is sufllciently dissolved in the solvent after which the cloth bag is raised to the dotted line position of Figure l and permitted to drain into the kettle. This operation constitutes an instantaneous hot filtration, and eliminates a jacketed pump and pipes normally required, as well as a second tank needed as a receiver after filtration.

Cooling the liquid B will now cause the dissolved ergosterol to recrystallize on the walls of the kettle. The rapidity with which this occurs will depend very largely on the rapidity of cooling this liquid. If all of the

valves

34, 31 and 44 are closed, the water in the jacket will cool but slowly, due to the efiiciency of the heat insulation I2. If, however, it is desired that the rate of cooling be accelerated, the operator will open the valve 31 and a thermosyphon action will take place which .will greatly increase the rate of cooling due to the fact that the cylinder 38 is not heat insulated. Should he wish to increase the rate still further, cooling water is allowed to circulate through coil 45. This accelerates the thermosyphon and yet gives good control of the cooling rate. By this method, there are no large local difierences in temperature in the jacket. A greater increased cooling rate may be obtained by admitting cold water to valve 44, the hot water overflowing through the expansion tank. When cooling is done by this method, there is an abrupt change in temperature as the level of the cooling water gradually rises from the intake valve and finally reaches the expansion tank.

Thus it will be seen that a very eflicient and self-contained apparatus is provided for the recovery of certain chemicals in purified crystalline form; the operator is enabled to control the rate of solution and recrystallization to a very high degree in addition to carrying out such usual operations a recovery of solvent.

After the mother liquor has been drawn oi! through the valve 58, the crystals deposited on the walls of the kettle may be washed with any suitable liquid such as a small'amount of the purified solvent C in receiver 08 which may be forced into the kettle by the pump 11 and then drained of! by the valve 56. These crystals may then be removed from the kettle and spread out to dry.

This type of apparatus has been found very I useful for purifying such materials as ergosterol as described in the example. It is also similarly useful for extraction of drugs and other chemicals from a mass consisting of unimportant insoluble or partly soluble material. At times when the apparatus is used for such purpose, it is naturally convenient to carry out a simultaneous crystallization of the extracted material. If the extraction has been carried out with hot solvent, it will often be possible to crystallize merely upon cooling the solvent. At other times, it will be found necessary to distill off part of the solvent after extraction has been completed and then crystallize the product from the resulting concentrated solution. It is also obvious that solvent recovery may be carried out in the apparatus as a separate operation to provide fresh solvent for future extractions. This and other variations of the use of the equipment would be obvious to the operator.

Depending upon the size and construction of the equipment, some of the details of construction can be varied considerably; for example: instead of having a removable cover, it is possible to have a completely enclosed tank to which access is allowed by means of a manhole; after each operation, the product can be removed and new material introduced through such an opening.

Similarly the water Jacket may be replaced by a steam jacket or by means of hot air as desired. However, in such a case one loses the advantages of the thermosyphon method of controllingthe rate of cooling.

We claim as our invention:

1. Apparatus of the class described comprising a kettle having a jacket for holding a heat exchange medium, a closure for the kettle, a

porous container constructed to hold a substance, to be treated within the kettle, supporting for the container extending through the closure, driving means connected to the supporting means for reciprocating the container through a predetermined path within the kettle, andmeans associated with the supporting means for lifting and maintaining the container above said path.

2. Apparatus of the class described. comprising a kettle having a jacket for holding a heat exchange medium, a closure for the kettle, a porous container constructed to hold a substance to be treated within the kettle, supporting means for the container extending through the closure, driving means connected to the supporting means for reciprocating the container through a predetermined path within the kettle. means associated with the supporting means for lifting and maintaining the container above said path, piping connected to the top andbottom portions of the kettle jacket, and said piping having means for introducing, withdrawing and circulating the for the container extending heat exchange medium within jacket.

3. Apparatus of the class described comprising a kettle having a Jacket for holding a heat exchange medium, a closure for the kettle, a porous container constructed to hold a substance to be treated within the kettle, supporting means for the container extending through the closure, driving means connected to the supporting means for reciprocating the container through a predetermined path within the kettle, means associated with the supporting means for lifting and maintaining the container above said path, piping connecting the top and bottom portions of the kettle Jacket, and valve means in said piping for controlling the flow of the heat exchange medium therethrough.

4. Apparatus of the the piping and class described comprising a kettle having a jacket for holding a heat exchange medium, a closure for the kettle, a porous container constructed to hold a substance to be treated within the kettle, supporting means for the container extending through the closure,

driving means connected to the supporting means for reciprocating the container through a predetermined path within the kettle', means associated with the supporting means for lifting and maintaining the container above saidpath, piping connecting the top and bottom portions of the kettle Jacket, said piping having means for circulating and controlling the flow of the heat exchange medium within the Jacket, and means associated with the piping for varying the temperature of the heat exchange medium therein.

5. Apparatus of the class described comprisexchange medium, for the kettle. a porous container constructed to hold a substance to be treated within the kettle, supporting means through the closure, driving means connected to the supporting means for reciprocating the container through a predetermined path within the kettle, means associated with the supporting means for lifting and maintaining the container above said path, piping connected to an upper portion of the kettle for withdrawing vapors therefrom, condensing and collecting means connected to said piping, means connected to a bottom portion of the kettie for withdrawing and collecting liquid thererom, and a pump having piping connected to each of said collecting means and to the kettle for returning liquid to the kettle.

' 6. Apparatus of the class described comprising a kettle having a jacket for holding a heat exchange medium, a closure for the kettle, a porouscontainer constructed to hold a substance to be treated within the kettle, supporting means for the container extending through the closure, driving means connected to the supporting means for reciprocating the container through a predetermined path within the kettle, means associated with the supporting means for lifting and maintaining the container above said path, pipingconnected to an upper portion of the kettle for withdrawing vapors therefrom, condensing and collecting means connected to said piping, means connected to a bottom portion of the kettle for withdrawing and collecting liquid therefrom, a pump having piping connected to each of said collecting means and to the kettle for returning liquid to the kettle, other piping con-- necting the top and bottom portions of the kettle jacket, said other piping having means for circulating and controlling the flow of heat exchange medium within the jacket, and means associated with said other piping for varying the temperature oi the heat exchange medium therein.

WALTER A. CARLSON. PAUL W. SALO.