Patent ID: 8807464

Claim:
A powder coating system comprising: a powder pump and a powder spray gun, said powder pump having at least one pump chamber in fluid communication with a powder coating material supply and the powder spray gun, wherein powder coating material is supplied to said spray gun from said powder pump, said powder pump pulling powder coating material into said at least one pump chamber under negative pressure and discharging powder coating material from said at least one pump chamber under positive pressure, said at least one pump chamber comprising a pump chamber inlet that can be selectively opened and closed and a pump chamber outlet that can be selectively opened and closed; said powder spray gun comprising: a powder inlet; a powder outlet through which powder coating material is sprayed; an electrode to charge powder coating material sprayed through said powder outlet; an air inlet connectable to a source of pressurized air; a housing; a powder passageway, enclosed within said housing, through which powder coating material, that is supplied to said powder inlet, flows to said powder outlet; a first air passage, enclosed within said housing, through which pressurized air flows that is supplied to said air inlet; an electrically conductive ring having a plurality of air passages, said electrically conductive ring being electrically in continuity with said electrode; a filter element that is disposed between said electrically conductive ring and said powder outlet, wherein said pressurized air flows from said air inlet through said first air passage, flows from said first air passage through said plurality of air passages in said electrically conductive ring, from said plurality of air passages in said electrically conductive ring through said filter element, and from said filter element into the powder coating material that flows through said powder spray gun.