Colour change system for powder coating

1. A colour change system for a powder coating facility, comprising:

a plurality of powder containers, each powder container holding one of a plurality of different coloured coating powders;

a conduit for conveying coating powder from one of the powder containers to a coating applicator;

a suction unit connected to the conduit and having an end-piece with an inlet opening into which coating powder is drawn, wherein the suction unit comprises an inducer in the end-piece adjacent to the inlet opening of the suction unit, and wherein the inducer comprises an air nozzle and a venturi tube section;

a cleaning unit;

a translation mechanism for moving the end-piece of the suction unit; and

a controller, wherein:

each of the plurality of powder containers has an opening in an upper surface into which the end-piece of the suction unit can be inserted;

the cleaning unit comprises a top opening for receiving the end-piece of the suction unit, a vertically-oriented chamber for receiving the end-piece of the suction unit through the top opening, a first air blowing arrangement for cleaning an outer surface of the conduit within the vertically-oriented chamber, and a second air blowing arrangement for cleaning insides of the suction unit and the conduit within the vertically-oriented chamber; and

the controller is configured to effect a change of coating powder colour by controlling the translation mechanism to extract the end-piece of the suction unit from a first powder container, to move the end-piece of the suction unit to the cleaning unit, and after cleaning to move the end-piece to a second, different powder container and insert the end-piece into the second, different powder container.

2. The colour change system of claim 1 , wherein the translation mechanism comprises mechanisms providing a vertical or y-direction translation of the end-piece, a first horizontal or x-direction translation of the end-piece, and a third or z-direction translation of the end-piece, wherein movement in the third direction moves the end-piece out of alignment with the openings in the upper surfaces of the powder containers.

3. The colour change system of claim 2 , wherein movement in each of the y-direction, x-direction and z-direction is independently controllable by the controller.

4. The colour change system of claim 1 , wherein the translation mechanism comprises at least one pneumatically operated cylinder.

5. The colour change system of claim 1 , wherein the first air blowing arrangement comprises one or more nozzles through which air is blown into the vertically-oriented chamber and over the outer surface of the conduit, and an air outlet for removing air and powder removed off the outer surface of the conduit from the vertically-oriented chamber.

6. The colour change system of claim 5 , wherein the one or more nozzles are located adjacent the top opening and the air outlet is located adjacent a bottom of the vertically-oriented chamber.

7. The colour change system of claim 5 , wherein the air outlet is configured to couple to a suction device configured to provide suction to draw air and powder out of the air outlet.

8. The colour change system of claim 1 , wherein the second air blowing arrangement comprises an air inlet for blowing air into the inlet opening of the suction unit.

9. The colour change system of claim 8 , wherein the second air blowing arrangement comprises a spring valve that is configured to be activated by contact from the end-piece of the suction unit to open and permit air to be blown into the inlet opening of the suction unit.

10. The colour change system of claim 1 , wherein the inducer is located at one end of a tube that connects to the conduit and the suction unit further comprises a passage for compressed air to be provided to the air nozzle.

11. The colour change system of claim 1 , wherein the inlet opening of the suction unit comprises a plurality of inlet channels leading from an exterior of the end-piece to the inducer.

12. The colour change system of claim 1 , wherein the suction unit further comprises an air duct for providing air to fluidise powder in the vicinity of the inlet opening.

13. A method of changing colour in a powder coating facility, the method comprising:

providing a colour changing apparatus comprising:

a plurality of powder containers, each powder container holding one of a plurality of different coloured coating powders;

a conduit for conveying coating powder from one of the powder containers to a coating applicator;

a suction unit connected to the conduit and having an end-piece with an inlet opening into which coating powder is drawn, wherein the suction unit comprises an inducer in the end-piece adjacent to the inlet opening of the end-piece, and wherein the inducer comprises an air nozzle and a venturi tube section;

a cleaning unit comprising a vertically-oriented chamber for receiving the conduit and the end-piece of the suction unit, a first air blowing arrangement for cleaning an outer surface of the conduit within the vertically-oriented chamber, and a second air blowing arrangement for cleaning insides of the suction unit and the conduit within the vertically-oriented chamber; and

a translation mechanism for moving the end-piece of the suction unit;

extracting the end-piece of the suction unit from a first powder container;

moving the suction unit to the cleaning unit and inserting the conduit and the suction unit into the vertically-oriented chamber of the cleaning unit;

cleaning the suction unit and the conduit within the vertically-oriented chamber with air discharged from the first air blowing arrangement and the second air blowing arrangement;

providing suction to the vertically-oriented chamber of the cleaning unit to draw air out of the vertically-oriented chamber of the cleaning unit

after cleaning, moving the suction unit to a second, different powder container; and

inserting the end-piece of the suction unit into the second, different powder container.