R and D series high vacuum pumps are used when the final absolute pressure required is very low <0.5 mbar (abs.). These pumps may run continuously connected to closed containers to be emptied, and may not run continuously at length, at atmospheric pressure. The exhaust from these pumps is not filtered, and thus special purifiers are available for fumes if necessary. The main areas of use include: refrigeration and air conditioning systems, laboratory applications, freeze-drying, spectrometry, ultracentrifugation.