IMPROVISED TRAPS FOR VACUUM LINES M. BLOOM Hushes Aircraft Company, Culver City, California
IT IS often necessary to place a series of traps in a vacuum line, either to protect the pump or t o collect fractions of differing volatility. The improvised trap arrangement described here has the advantage that it does not involve the use of rubber tubing or stoppers and is consequently free of contamination from these sources. Moreover, the capacity of each trap is large, and condensed liquid drains away leaving the vacuum line free of obstruction. Each trap consists of the heating chamber portion of an Abderhalden drying apparatus. The trap is mounted with its main axis vertical and the sample chamber filled with a refrigerant such as ice water, dry ice and acetone, liquid nitrogen, etc. The ground-glass joints on the heating chamber, which are ordinarily used for attachment of the boiling-flask and reflux condenser, are now used for assembling the vacuum line. If de-
VOLUME 34, NO. 4, APRIL, 1957
sired, each trap can be placed in a Dewar flask for additional cooling, but this is generally not necessary unless the trap is to be left unattended for a long period of time.
