A liquid ring pump comprises a first housing part that radially encloses two or more working chambers in which a rotatably mounted impeller is disposed in an eccentric manner, second and third housing parts that seal both sides of the first housing part and the pump, ducts or chambers for delivering and discharging the conveyed gas, and control disks that delimit the working chambers in an axial direction. The first housing part is embodied as a single piece while a connecting duct is provided which extends from the second to the third housing parts, and the ports facing the respective adjacent housing parts are configured such that the second and third housing parts can be embodied in an identical manner.