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The cheap and simple water aspirator is commonly used in chemistry and biology laboratories and consists of a tee fitting attached to a tap and has a hose barb at one side. The flow of water passes through the straight portion of the tee, which has a restriction at the intersection, where the hose barb is attached.
Diagram of the vacuum filtration apparatus. By flowing through the aspirator, water will suck out the air contained in the vacuum flask and the Büchner flask.There is therefore a difference in pressure between the exterior and the interior of the flasks : the contents of the Büchner funnel are sucked towards the vacuum flask.
Preferably this is done through a trap (see below), which is designed to prevent the sucking back of water from the aspirator into the Büchner flask. The purpose of applying a vacuum is to speed the filtration by providing a pressure differential across the filter medium that is greater than that produced by gravity alone.
The potential for overflow and the potential for water to be drawn back into the flask can be reduced by using a trap between the flask and the vacuum source. It is used in organic chemistry labs to assist in collecting recrystallized compounds.
Typically the vacuum is generated by a water aspirator or a membrane pump. In a Kugelrohr apparatus a short path distillation apparatus is typically used (generally in combination with a (high) vacuum) to distill high boiling (> 300 °C) compounds.
A rotary evaporator [1] (rotovap) is a device used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation.When referenced in the chemistry research literature, description of the use of this technique and equipment may include the phrase "rotary evaporator", though use is often rather signaled by other language (e.g., "the sample was evaporated ...
The liquid spray coming from the nozzle creates a partial vacuum in the side duct of the scrubber. The partial vacuum is due to the Bernoulli effect, and is similar to water aspirators used in chemistry labs. This partial vacuum can be used to move the process gas through the venturi as well as through the facility's process system.
A Büchner funnel with a sintered glass disc. Laboratory funnels are funnels that have been made for use in the chemical laboratory. There are many different kinds of funnels that have been adapted for these specialized applications.