Abstract: A distilling unit for distilling a sample wherein the distillate is passed in a closed system into a receiver, comprises a heatable distilling vessel, a spray or splash protection means, a condenser and a distillate discharge pipe which dips into liquid in the receiver. In order to ensure that, when the distilling operation is interrupted after a predetermined period of time, the liquid is not sucked back into the apparatus by the vacuum which is formed, the distillate discharge pipe has a non-return valve which vents the apparatus when there is the slightest reduced pressure. In this way, the conventional support plate no longer has to be lowered by expensive lifting means, as hitherto.