Abstract: Gas delivery valve, in particular of the demand-valve type, having a valve body (1) in which is made a main passage (11) for routing gas comprising a gas inlet orifice (12) and a gas outlet orifice (13), valve means (33) arranged on the internal passage (11) for routing gas, between the said gas inlet orifice (12) and outlet orifice (13), making it possible to control the flow of gas in the said main internal passage (11) for routing gas, a line (14) for detecting a pneumatic vacuum co-operating with the said valve means (33) in order to allow, at least temporarily, the flow of gas in the said main internal passage (11) for routing gas between the said inlet orifice (12) and outlet orifice (13). The valve further comprises a secondary passage (8) for routing gas which is fluidically connected to the main gas routing passage (11) upstream (11a) and downstream (11b) of the said valve means (33).