Abstract: A displacement pump with a pot-shaped housing, a rotor which is swivel-mounted about a rotation axis inside the housing, and two blades which are guided in a movable manner insider the rotor, wherein the pot-shaped housing includes an inner peripheral wall which has a sealing portion for tightly adjoining the rotor and a chamber portion for tightly adjoining the blade tips, as well as for dividing the internal space of the housing into chambers. The rotor has two blade receptacles for receiving and guiding the blades, wherein each internal radially extending blade tip restricts a pressure chamber in the respective blade receptacle. Both pressure chambers are fluid-connected to one another via a connection element, wherein the total volume of both pressure chambers and the connection element remains at the same level during a rotation of the rotor, at least while the blade tips are attached to the chamber portion.