Abstract: The invention relates to encapsulating machines and more especially to the device for putting the capsules in position in the encapsulation head. It consists in the creation in the air duct for propulsion of the capsules of one or more chambers for successive expansions of the air separated by nozzles the ratio of the bores of which is such that the incomplete expansion of the air is obtained in each intermediate chamber and the expansion is complete at the output in the ambient air. In one embodiment the cross-section of the outlet nozzle appears in the form of a flattened tube and the expansion chamber is filled with an acoustic insulation material. (FIG. 4). In another embodiment, a plurality of channels surround the outlet nozzle which communicate with the atmosphere and thereby introduce air into the outlet nozzle, providing a continuous circulation of air round the device. (FIG. 6).