Patent GB-802954-A (GB)
Title: Improvements relating to apparatus for effecting distribution of a solute between two liquid phases
IPC: B01J19/28
Filed: 1955-03-23
Abstract: 802,954. Purifying liquids. GILSON, A. R., and WRIGHT, A. G. March 22, 1956 [March 23, 1955], No. 8497/55. Class 46. [Also in Group XXXVII] The invention provides a drive unit to operate, automatically, " Craig " countercurrent apparatus which effects distribution of a solute between two liquid phases. In such apparatus several tubular vessels are arranged side by side and a predetermined quantity of the heavier phase is placed in each vessel while a predetermined quantity of the lighter phase is placed in the first vessel only, (the solute being initially contained in one phase only). The array of vessels is coupled at 7, Fig. 3, to the shaft 5 of the drive unit, and a main switch and a push-button starter switch on the control-panel 25, Fig. 2, of the drive unit housing 1 are operated. An electric motor 19 is thereby energized (see Group XXXVII) and drives a shaft 14 on which is eccentrically mounted a disc 13 which through roller 12, lever 10, link 9 and crank 8 rocks the shaft 5 so that the array of vessels is rocked about the horizontal to cause thorough mixing of the phases in the first vessel. After a lapse of time governed by a first pre-set timer on the panel 25 the main circuit of the motor 19 is automatically opened and when the array of vessels next reaches a horizontal position a limit switch LS, Fig. 4, in a shunt lead to the motor, is opened by movement away from it of a cam 60 secured to shaft 14, the array thereupon coming to rest. The limit switch is secured to a bracket 59 loosely mounted on the shaft 14 and angularly adjustable by a knob 41, Fig. 3, so that the rest position of the array may be adjusted. The array remains at rest for a period governed by a second pre-set timer switched in by the first, a light on the panel 25 indicating that the unit though at rest is still functioning. At the end of this period a third timer, switched in by the second, switches on the motor (not shown) of a screw jack 22, Fig, 2, which lifts a lever 20 which engages under the lever 10, Fig. 3, thereby partrotating the shaft 5 to bring the array into a vertical position, whereupon the jack motor switches off. While the array is in the vertical position the top phase (which has separated during the resting period) is decanted off into a side tube of the first vessel. Thereafter the third timer switches on the jack motor to retract the jack 22 so that the array resumes the horizontal position, whereupon the top phase passes from the side tube into the second vessel. The jack motor switches off at the end of the retraction, and the complete cycle recommences with the rocking phase. After a predetermined number of cycles selected on a cycle counter on the panel the push-button starter switch is automatically opened and the fact indicated by a flashing or steady light on the panel, and optionally, other means. When the apparatus is in the rocking or resting phase it can be brought to, or maintained at, rest at any time by operating an inspection switch (with indicator light), and during this interruption the apparatus may remain at rest for an unlimited period or, by operating a further switch, rocked for an unlimited period, or, by operating yet another switch, raised to the vertical and lowered again an unlimited number of times. When the inspection switch is restored the cycle resumes from where it was interrupted. When the inspection switch is operated during the " raising and lowering " phase, that phase is completed before the apparatus comes to rest, and when the inspection switch is restored the next rocking phase begins. After the apparatus has first come to rest during such interruption, however, it may be made to perform any of its three functions indefinitely in the same way as described above. The jack 22 and motor may be replaced by a hydraulic jack, pump and pump-motor. An automatic feed device may feed the appropriate quantity of top-phase liquid into the first vessel each time the vessels are returned to the horizontal position from the vertical ; a table carrying a plurality of receivers may be rotated through a pre-determined angle every time the cycle counter advances by one unit, so that each fraction of topphase discharged from the side tube of the last vessel of the apparatus will be collected in a separate receiver. According to the Provisional Specification the cycle counter is actuated once in each cycle by engagement of the lever 20 with a contact arm which closes a pair of contacts. Also the counter remains in circuit during " raising and lowering " phases performed while the inspection switch is in operation.