A Venturi pump used for sucking powder from a supply, diluting the same, then feeding it to a gun via a conveyor pipe. The pump comprises an outer body, at least one powder suction duct, at least two air connections, of which a first air connection is capable of supplying an injector to create a vacuum inside the suction duct and a second air connection is capable of supplying a dilution air circuit separate from the powder flow. The pump including at least one powder outlet nozzle centered on an axis of diffusion, the inlet of which is located downstream from the first air connection and the suction duct. At least one protection barrier contains a non-return valve disposed inside the dilution air circuit and at least one outlet tip of the dilution circuit disposed around the nozzle and also connected to the conveyor pipe.