Vacuum concentrators

Vacuum concentration makes many demands on the supporting vacuum system, both in terms of the ultimate vacuum and in the selection of accessories. The pump needs high resistance to chemicals, as well as good tolerance of condensates. Type of solvents in use and the nature of the samples both have a strong influence on the ultimate vacuum needed and the appropriate type of process controls. Determining the optimum heat transfer into the sample material is also vital to avoid the need to upgrade your pump later.

Process requirements

• optimum heat transmission to the sample vessels
• medium to high vacuum requirements
• fast and highly sensitive vacuum regulation with samples that tend to foam
• condensate and droplet precipitation between the pump and concentrator

Demands made of the vacuum pump

• great resistance to chemicals
• ultimate vacuum as much as 7 mbar or 1.5 mbar
• sufficient volume flow rate (2 m³/h and more)
• not sensitive to condensate
• inclusion of a vacuum inlet separator (AK) made of glass to protect the pump from particles and droplets of liquid
• emission condenser for solvent recovery and to minimize environmental and laboratory air pollution

Recommended systems

An ultimate vacuum of as much as 7 mbar is sufficient for organic solvents and/or small amounts of H₂O

An ultimate vacuum of as much as 1.5 mbar is advisable for aqueous samples, high boiling point solvents and/or low working temperatures.
This especially concerns solvents such as DMF, DMSO, NMP or DMAC.

VARIO^® pumping units with automatic vacuum optimization are the best option for gentle concentration operations and for mixtures of substances that tend to boiling delay.

Final pressures of as low as 10^-3 mbar may be necessary for optimum residual drying or for high-temperature boilers at very low evaporation temperature. The chemistry-HYBRID^TM pump RC 6 has proved its worth here.

A cold trap can be located upstream of any of the pumps to boost flow-through, if helpful.