This compact piece is designed for use with small quantities where hold up between the flask and receiver must be kept to a minimum and is also ideal for Schlenk line work. The thermometer bulb and stem serve as column packing. The upper hose connections are for cooling lines and the lower connection is for vacuum. All sizes have optional Vigreux indentations to improve efficiency.
The size with inner 14/20 joints accepts a 1" immersion 7/12 or 10/18 thermometer, while the 24/40 accepts a 2" immersion 10/30 or 14/20 thermometer.
Application note: Some vacuum distillations need to be performed at a specific pressure rather than full dynamic vacuum. To maintain a relatively low vacuum (~2-50 torr), once can use an adjustable bubbler such as item #AF-0513-A-21 as a low-tech vacuum control (manostat). For those situations where you need to operate at pressures as high as 760 torr or want to avoid the use of mercury (a good idea), consider a Mano-Watch™ vacuum controller/monitor, item #20900-A.