Pressurized-gas supply unit

A pressurized-gas supply unit has a feed valve (11) connectable to a pressurized-gas source (4), and which operates in pulsating manner to feed pressurized gas in pulses to a user device (2); and a safety valve (12) connected pneumatically to the feed valve (11) to cut off pressurized-gas supply to the user device (2) as a function of the duration of each feed pulse.