초록 ▼

A spray powder-coating apparatus fitted with an electronic control system (21) regulating the air flows (20, 43) to an injector (4) as a function of setpoints (m) for the rates of powder to be moved, and as a function of a setpoint (GV) for the total rate of air passing through the nozzle, by means

A spray powder-coating apparatus fitted with an electronic control system (21) regulating the air flows (20, 43) to an injector (4) as a function of setpoints (m) for the rates of powder to be moved, and as a function of a setpoint (GV) for the total rate of air passing through the nozzle, by means of motor-driven adjustable throttles (18, 19, 44, 45), preferably also as a function of the actual values (89, 90) of the regulated air flows (20, 43).

대표청구항 ▼

1. 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

1. 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). 2. Spray powder-coating apparatus as claimed in claim 1, characterized in that the supplemental air line (43) is connected to a supplemental-air intake (46) of the injector (4) issuing downstream of the partial-vacuum zone (10) into the powder/air duct (2) to implement the feed of compressed air acting as the supplemental air, in that a variable throttle (44) is mounted in the supplemental-air line (43) and its flow impedance is adjusted by a motor, and in that the throttle (44) is operationally connected to an adjustment motor (45) driven by means of those adjustment signals from the regulation system which are a function of the powder setpoint (m) and of a setpoint value for the rate of total air passing through the powder/air duct (2). 3. Spray powder-coating apparatus as claimed in claim 1, characterized in that a powder-aspirating duct (8) is connected to the partial-vacuum zone (10), in that a compensation-air intake (56) feeding compensation air into the powder aspirating duct (8) to compensate any flow pulsations is connected to the end of the powder aspirating duct (8) which is away from the partial-vacuum zone (10), where the rate of applied compensation air is substantially smaller than the rate of applied conveyance air. 4. Spray powder-coating apparatus as claimed in claim 3, characterized in that a variable throttle (62) exhibiting motor-controlled flow impedance is mounted in the compensation-air line (64) and in that the throttle (62) is operationally connected to an adjustment motor (63) which in turn is driven and regulated by the regulation system (21). 5. Spray powder-coating apparatus as claimed in claim 1, characterized in that a measuring element (89) is mounted in the conveyance-air line (20) downstream from its throttle (18) and generates a signal of actual value as a function of the flow conditions in the conveyance-air line to the control system (21), in that the control system (21) is designed in such manner that it generates the setpoint signals for this throttle (18) also as a function of said signals of actual values of the conveyance air. 6. Spray powder-coating apparatus as claimed in claim 1, characterized in that a measuring element (90) is mounted in the supplemental-air line (43) downstream of its throttle (44) and generates a signal of actual value as a function of the flow condition in the supplemental-air line (43) to the regulating system (21), and in that it also generates the setpoint signals for this throttle (44) as a function of said signals of the actual value of the supplemental air.