The special water-jet pump for continuous automatic working previously descr. by the author has been improved, so that 3 functions, evacuating, cooling and removal of the condensate, are fulfilled by this one special pump. A large apparatus has also been devised fitted with a 7-tube condenser and 3 pumps, in which, when a full vacuum has been obtained, a single special pump suffices for maintenance of the vacuum, cooling and draining off the condensate at an efficiency of 5 liters per hr. at 20[degree]. The efficiency of this larger apparatus can be increased to 10 liters water per hr. at 20[degree] by using a vessel of 30 1. capacity which is heated directly. Efficiencies up to 30 1. per hr. may be attained if sufficient increase of heat in proportion to the condenser capacity can be applied to the boiling vessel.