A pressure exchanger (1) including a housing (2), a drive shaft (3) and a cylinder drum (4) rotatably arranged in the housing (2) is described, the cylinder drum (4) including two front faces and at least one cylinder (5) between the front faces, wherein the housing (2) includes a port flange (7, 8) at each end of the cylinder drum (4) and at least at one end of the cylinder drum (4) a pressure shoe (18) is arranged between the cylinder drum (4) and the port flange of this end. Such a pressure exchanger should be operated in a cost-effective manner. To this end an adjustable stop arrangement (19) is arranged between the pressure shoe (18) and the cylinder drum (4).