Welch Vacuum has addressed the problems associated with oil-sealed rotary vane pumps in vacuum drying applications and high boiling point stripping with the launch of a new pump which can do both. The Gem pump matches the performance of oil-sealed rotary designs by offering vacuum levels to 0.1 mbar, whilst at the same time offering dry pump performance by being able to run continuously at or near atmospheric pressure with compromising reliability.

Whilst conventional oil-sealed rotary vane pumps are adept at providing the deep vacuum required for laboratory drying applications, they tend to be unsuited to continuous use above 2 mbar. The high compression ratio required to achieve deep vacuum becomes a problem at pressures in the mid hundreds of millibars: the high compression of high gas loads makes conventional pumps run excessively hot, causing oil leaks, and oil mist to be exhausted into the lab. At the same time, the high compression ratio can lead to vapour condensation problems inside conventional pump mechanisms; and if the condensate is acidic, this can attack and break down the oil, compromising reliability.

Welch has solved these problems with the Gem pump by using an unique and patented gerotor gear mechanism at the heart of the design. Able to provide ultimate vacuum down to 0.1 mbar and flow rates up to 31 l/min and operate continuously at any pressure level, the Gem runs much cooler than rotary vane pumps, and operates with a much lower compression ratio, boosting long term reliability.

Compact and readily portable, the Gem pump is also designed for ease of use. Each pump comes equipped with a vacuum gauge to monitor the vacuum level, a regulator to adjust the vacuum, and an exhaust mist recycler to recover oil mist and recycle the oil back into the pump. Welch Vacuum pumps are available across Europe from ASF Thomas.

Picture: Source: Rietschle Thomas