Direct-injection spraying device for an agricultural vehicle, comprises: a main tank； at least one spray boom； at least one active substance store； a cyclone mixer, in which a first portion comprises at least first and second tangential inlet ports, and a second portion comprises an outlet port； and a fluid circuit comprising a main pump, at least one inlet duct, at least one bypass controlling a flow rate in the boom in accordance with a traveling speed of the vehicle, at least one metering pump inserted between the store of active substance and second port, and at least one outlet duct. Direct-injection spraying device for an agricultural vehicle, comprises: a main tank； at least one spray boom； at least one active substance store； a cyclone mixer, in which a first portion comprises at least first and second tangential inlet ports, and a second portion comprises an outlet port； and a fluid circuit comprising a main pump, at least one inlet duct connecting the tank to the first port, at least one bypass controlling a flow rate in the boom in accordance with a traveling speed of the vehicle (where the bypass is connected to a regulating valve), at least one metering pump inserted between the store of active substance and the second port, and at least one outlet duct connecting the outlet port to the boom.
