An Inexpensive Shield for Vacuum Distillations Vacuum distillation isan mportnnt rrchntque for Cqana i.hemi*tryrturlenL\ turnaster. H~~wrvrr,rafrtyconsidrrations demand the use of safety shields b r t w r n the nppnmtus and thc student. Ommrrrially availahle ahirlds are horh cosrly and restricted in si,c and shape. Wr haw developed nn inexpensive ihield that utdi,r, ,hrct acrylic brnt t o thr desired shape. We used 'I4- X 24- X 32 in. sheets which allowed six sheets t o he cut from the 4- X 8-ft sheets of acrylic available a t hardware and building supply stores.' These small sheets were bent 6 in. in from each end of the 32 in. side a t a 90" angle "U" shape 6 X 20 X 6 in. and 24 in. high. This fits around a ring stand holding a micro distillation set-up, providing both side and front protection to the student. Bending was done on a homemade form by placing the sheet to be bent over the heater wire far about 2 min, or until pliable; then bending to a 90' angle, removing from the heat, and holding the angle until it cools enough t o retain the desired shape.
#
Coil
-:
I
3 1 1 ~ "A I ~ ~ S IBOo aSr d
I 2 x 4
-3/40
u
Plywood 36x24
2 x 4
The heater coil was fabricated from 12 ft of #22 Nichrome wire ( 1 ohmlft) wound into a coil and stretched to 24 in. length. The ends of the coil were connected to machine screws and then t o a Variac set to about 70 V.
A sheet of 'I4-in. acrylic (4 X 8 ft) costs $95/sheet and yields a per shield Cost of about $16.
W. David Loehle United States Military Academy West Paint. NY 10996
570
Journal of Chemical Education
