Powder spray coating device

A spray powder-coating apparatus comprising an injector (4) fitted with a partial-vacuum zone (10) between an injector nozzle (6) and an axially opposite powder/air duct (2) for the purpose of aspirating powder out of a powder source, further comprising a conveyance-air line (20) connected to the injector nozzle in order to feed said nozzle with conveyance air in the form of compressed air, an electronic control system (21) to regulate the conveyance air as a function of a powder setpoint value and of an actual powder value of the rate of conveyed powder, a measurement system (30, 36, 38) connected to the partial-vacuum zone (10) of the injector (4) and feeding a signal of the actual value corresponding to the particular partial vacuum to the regulation system (21), said signal of actual value being interpreted by the regulation system (21) as the rate of conveyed powder, further an adjusting element (18) in the conveyance air line (20) to adjust the conveyance air by means of the regulation system (21) as a function of the powder setpoint value and of the actual value of this powder,

• characterized in that the adjusting element (18) is a variable throttle (18) of which the flow impedance is adjusted by a motor, in that the throttle (18) is driven by an adjustment motor (19) in turn driven by adjustment signals generated by the regulation signal (21).