Many digestion applications, e.g. Kjeldahl, produce fumes that are unpleasant and corrosive. Exhaust Manifolds designed for each Digestion Unit facilitate fume removal and containment and are strongly recommended for use with all digestion procedures. The cost of replacement of a fume cupboard which has been corroded by inefficient fume handling is very much greater than the relatively low cost of an approved exhaust. Whilst many users choose to operate integrated systems in the open laboratory, we strongly recommend the use of both exhaust systems and fume cupboards for these operations. This is simply Good Laboratory Practice (GLP) and avoids conflict with local Health & Safety (H&S) requirements.
The Exhaust Manifolds should be connected to the water aspirator supplied, or to a suitable Scrubber Unit.
Scrubber Unit
Where water is a scarce or expensive commodity, or simply when a higher level of automation is desired, the water aspirator should be replaced with an efficient Scrubber Unit. Exhaust Manifolds and Scrubber Units which require an external water source are subject to variation in vacuum efficiency due to fluctuations in local water pressure.
The compact bench top Tecator™ Scrubber Unit is self contained and is therefore unaffected by water supply issues. During digestion moist, acidic fumes from the connected exhaust are drawn through the Scrubber Unit. Acid vapours are first condensed and diluted in a large acid trap. Any residual fumes are collected, washed and neutralised before passing through a second small acid trap which protects the vacuum pump in the event that the scrubbing agents are exhausted. The cleaned air is then vented via a tubing outlet. In the interest of GLP and H&S this venting tube should be directed into a fume cupboard. When the Scrubber Unit is connected to an Auto Lift or Auto Rack system the program will fully control the function including switching from high to low aspiration settings.
