Patent ID: 7413387

Claim:
A pneumatic distributor of at least one of granular and/or powdery materials, comprising: a main distribution duct having a first end in the region of an air-flow which is injected into the duct under pressure, and a second end, the main duct having respective adjacent converging-diverging portions, with reference to the direction of the air-flow, defining a Venturi duct, dosing means for delivering a metered quantity of material into the main duct in the region of the narrow cross-section portion of the Venturi duct, for the mixing of the material into the air-flow and the entrainment of the mixture obtained towards the second end, and at least one auxiliary air-flow duct, bypassing the Venturi duct in order to connect a section of the main duct disposed upstream of the Venturi duct to a section of the main duct disposed downstream of the Venturi duct, a portion of the air-flow injected into the distribution duct being tapped off by said auxiliary duct in the region of the section disposed upstream of the Venturi duct and being introduced, at a section downstream of the Venturi duct, into the air and material mixture produced in the main duct.