Let us consider a typical laboratory system where a 1 litre volume flask is being evacuated from atmospheric pressure every hour.
If 25% of the mass of oil, compared to the mass of the pumped air, is carried over (i.e. transferred with the pumped air) during each flask evacuation then
This suggests that in ~ 3300 cycles all the oil will be lost from the pump. At a rate of one cycle per hour this occurs in approximately 4 to 5 months. (Note that this could be confirmed by checking how often the oil in the Oil sealed rotary vane pump needs to be re-filled) and or we can surmise that in 3 months we would expect > 600 g of oil to be lost from the pump.
This will result in a layer of aromatic (smelly) oil of 0.1 mm thickness coating an area of 60,000 cm2 of the laboratory. As a comparison operating a pump at ultimate pressure (< 1 Pa) the mass flow of air is <0.001 g/h
nXDS scroll pumps are completely oil-free, hermetically sealed. They have no oil in the gas pathway so there is no potential contamination of the process nor of the laboratory environment. They can be configured to pump a wide range of laboratory applications and maintenance intervention is 2.5 years or more
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