The invention relates to a device which enables nozzles to be changed without changing the pressure conditions in the container or device associated therewith. According to the invention a connector piece support (2) is fixed to a pressurised container (1) wherein a medium (20) is guided into said container through a nozzle (8) by means of a lance (7). Said connector piece is connected to a sealing housing (5) by means of a locking device (3) in order to receive the lance (7). Sealing rings (13a, 13b, 13c) are arranged in the sealing housing (5) thereby ensuring pressure-tightness in relation to the container (1) and the surrounding area when the lance (7) is inserted into the sealing housing (5).