A. G. Oslroff Field Research laboratory Socony Mobil Oil Company Dallas, Texas
II
Closed System Stirring Apparatus
Described here is a simple device for stirring closed systems. This stirring apparatus has the advantage of being simple and economical to build, yet it can be used effectively in a sealed system without impairing the seal, it has no complicated pressure seal or coupling that is difficult to align, and it can be operated from the top of a temperature bath. In addition, the stirrer can be constructed of material that will not produce sparks that might ignite flammable vapors or of material that will stand appreciable pressures. This stirring apparatus is adaptable to studies requiring rotating electrodes by using a hollow shaft stirring rod for running the electrical leads and a slip ring connection for connecting the electrode to the outside of the stirrer enclosure. Figure 1 is a drawing of this stirring apparatus. A stirring rod equipped with a paddle is threaded on one end and passed through a bushing. The rod screws X 2 in.). into a head nut and against a magnet The rod then serves to hold the magnet in place. A sealed enclosure is placed around bushing, magnet and heat nut so that if the bushing is sealed in a container, the only opening would be between the stirring rod and hushing. This leads into the sealed enclosure so that there should be no loss of vapor. The stirrer is rotated by another magnet, head nut, and rod assembly placed directly over the enclosure and motivated by a stirring motor. In each stirring device used by the author, the stirring rod and enclosure were made from acrylic plastic, the bushing from Teflon, and the head nut from nylon. The stirring rod was made from oversize rod and the portion which passed through the bushing was turned down to '/, in. diameter. This left a shoulder on the rod which prevented the rod from pulling up when the impeller magnet was placed in position. A neoprene
266
/ Journal of Chemical Education
gasket sealed the enclosure top when i t was fastened in position. A rubber stopper was used to hold the stirrers in a flask. The author has used these stirrers in solubility experiments a t tempratnres as high as 70°C.
ENCLOSURE TOP
' 1/4IN.X2lN, MAGNET
BUSHING
Stirring apporotur for use in closed systems.
