Liquid ring gas pump with a working space in which an impeller (6) revolves and which is bounded axially by a control plate (7) past which the impeller (6) moves with a small clearance and which has at least one intake and/or one discharge opening (21, 22, 23) and is made of rolled sheet. According to the invention, the edges (26) of the intake or discharge opening are at least in part bent over towards the side facing away from the impeller (6) and are rounded on the side facing the impeller and raised on the side facing away from it. <IMAGE>