Abstract: A process for conveying boilable liquids wherein the required delivery pressure is generated by alternately changing the boiling pressure of a boilable liquid from a low starting point to a boiling pressure, increased by the desired increase in pressure, by an external heat input and then the original state is reproduced by reducing the pressure to the low boiling pressure by dissipating the heat externally, is improved by avoiding the use of highly stressed wearable parts and by being able to attain greater reliability and longer life span with a faster method. For this purpose, in the vessel through which the boilable liquid to be conveyed flows a subquantity of the boilable liquid being conveyed is subjected directly to the work performing cyclic process in the wet steam region.