Spider (laboratory device)
A spider - also known as an udder or spinning template - is a laboratory device made of glass as part of an apparatus for vacuum distillation . The spider allows several fractions to be fed into individual round or pointed flasks by rotating without interrupting the distillation.
Disadvantages of the spider, in addition to the limited number of fractions, are that it has to be clamped very precisely because otherwise glass breakage can occur and if the pressure is reduced in the course of the distillation, significant losses of the low-boiling fractions occur. In addition, in some cases detectable mixing of the fractions can occur through diffusion through the gas phase.
A more complicated and technically more complex alternative to the spider is the advance to Anschütz-Thiele , which does not have the problems mentioned above.
Spider with standard joint 29/32. Connection sleeve (above) and standard ground joint 14/23 connections for five receiver pistons (below)
Spider with NS 14/23 connecting sleeve (above) and NS 14/23 connections for four delivery pistons (below).
Spider with NS 14/23 connection core and attached angled distillation adapter (above) and NS 14/23 connections for four receiver flasks (below).
Individual evidence
- ^ Walter Wittenberger: Chemical laboratory technology. 7th edition, Springer, Vienna / New York, 1973, ISBN 3-211-81116-8 , p. 186.