Abstract: The invention relates to an ejector to be placed in rooms which are inaccible to human beings. It comprises a casing with a diffuser bore, a head chamber, and a space for a working fluid including a lateral working fluid connection. The working fluid nozzle comprises a working fluid chamber which is connected through bores with the working fluid space and, inside the casing, it seals the head chamber from the working fluid space. The nozzle of the working fluid chamber opens into the head chamber and faces the diffuser bore. The invention is characterized in that the ends of the casing and of the working fluid nozzle each are embodied as a radial flange which flanges are held together by bolts adapted to be operated by a manipulator. At the end of the working fluid nozzle flange there is a handle which is operable by a manipulator to pull the working fluid nozzle out of the casing and to reintroduce it, respectively.