These two portions cooperate with a shutting piece (14).

The filler piece (19) is set in rotation such that material of the filler piece (19) and of the housing part (10, 25) is heated and plastified by rotational friction.

A filler piece (19) which has a conical lateral surface (21) that fits in the conical bore (18, 27) is prepared.

The filler piece (19) and the housing part (12, 25) are compressed with respect to each other in the axial direction.

A plug (3) is fitted movably in the housing (1) and can be engaged with a valve seat (23).

The closure piece (8) is held in its closed position by means of a detent device (16) that can be released depending on a threshold temperature.

The device essentially comprises an obturating piece (62) provided with an arc-shaped slit (70) which is extended by a circular aperture (76).

The front side of the working piston at least partially forms the closure of the container or is rigidly connected to the closing element of the container.

The assembly is arranged such that, after the syringe has been used, the sealing piece no longer closes the opening permanently, so that the syringe cannot be used again.

This shutting piece (14) is provided with recesses (15, 16) for housing elastic dogs (3, 4), and each recess has a foldable tongue (17, 18).

Said closure element, when closed, bears on its outer periphery on a centrically arranged flow unit (5) to provide a seal.

The filler piece (19) is worked so as to finish flush with the housing part (12, 25).

The obturating piece (62) can be rotatably displaced about the point O on a circle whose radius (R) is equal to that of the slit (70).

Because of the distention of the sealing member (3), the slits (3a) are opened, and the gas is allowed to flow further through them into the bottle (4).

The filler piece (19) consists of a material which, compared with the material of the housing part (10, 25), has increased resistance to a specific loading.