A supply device of a fluid substance (200) comprises a pneumatic cylinder (211) and a movable dividing wall ( 215 ) located in the pneumatic cylinder (211), which is arranged to separate hermetically the pneumatic cylinder (211) in a first chamber (211a) and in a second chamber (211b), which is adapted to contain the fluid substance to supply and has at least one dispensing orifice (221) through which the fluid substance is dispensed. The device (200) also comprises a pneumatic circuit (350) arranged to connect pneumatically a source (300) of an operating pressurized fluid with the first chamber (211a). An actuating means (330) is also provided that is arranged to move from a first working configuration, connecting pneumatically the source (300) of operating fluid with the first chamber (211a) of the pneumatic cylinder (211), and a second working configuration, insulating pneumatically the source of operating fluid (300) from the first chamber (211a) of the pneumatic cylinder (211). In addition, it comprises an automatic discharge valve (100), which is arranged in the pneumatic circuit (350) and is configured in such a way that, when the actuating means (330) is in the second working configuration, the automatic discharge valve (100) discharges the fluid present in the first chamber (211a) of the pneumatic cylinder (211), stopping the movement of the movable dividing wall (215) and therefore blocking the supply of the fluid substance through the dispensing orifice (221).L'invention porte sur un dispositif d'alimentation d'une substance fluide (200), lequel dispositif comprend un cylindre pneumatique (211) et une paroi de division mobile (215) disposée dans le cylindre pneumatique (211), qui est agencée de façon à séparer hermétiquement le cylindre pneumatique (211) en une première chambre (211a) et une seconde chambre (211b), lequel dispositif est apte à contenir la substance fluide à fournir et a au moins une orifice de distribution (221) à travers lequel est distr
