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INDUSTRIAL AND ENGINEERING CHEMISTRY
Electromagnetic Stirring Device WILLIAM P Department of Phyri Washin!
Figure 1.
Diagram of Stining Device
Vol. 18, No. 5
line or through the 75-0hm resistance to the 110-volt direct current line. The solenoid is made of a brass spool with 2333.4 feet of No. 24 enamel-covered copper wire (0.022-inch diameter) which operates a lunger made of solid soft iron (height 1.25 inches, diametere!/6I inch). When the plunger, 1, is pulled down by the solenoid i t lowers 8 lever, 2, consisting of a brass tube in which an evacuated mercury interrupter, 3 (available a t Iahorrttory supply houses as made by Generd Electric, Minneapolis-Honeywell Regulator Ca., and Americm Instrument Co., Washington, D. C.), is situated, which,breaks the current when the lever reaches its lowest point, thus allowing the lever and plunger to be pushed up by a coil spring, 4. The tension of coil spring 5 a t the end of the lever, which can be changed by manipulation of a screw, 6, regulates in a very simple and reliable way the time i n t e r i d between the makeand-break of the current. The height of the pivot, 7, can also be regulated to give the meroury interrupter the proper inclination. A regulates the speed of the make-andbreak for an efficient stirring, whereas B is B stirring device activated by the intermittent, current supplied by A. The solenoid, 8, acts on the soft iron cores of the stirrer, 9, inside the closed apparatus, inducing an up and down motion of the stirrer. The solenoid is made of short brass pipe 1.5 inches Ion , wall thickness 0.12 inch brazed to a m i d steel round plate 5 inches in diameter and 0.12 inch thick. It has 1400 feet of No. 24 enamel-covered copper wire. The liquid is stirred by perforated plates, 10, attached to the stirrer, which is made (as is the whole apparatus) from nonmagnetic metal (copper or silver). This method of stirring is more efficient than rotating motion which has a '---'eney to move the e n t r e liquid. I A spiral spring, 11 situated at the bottom of the :~pparakusinterrbittently touches the lower pelf
