Patent ID: 8132743
Filing Date: 2012-03-13
Classification: B05B

Abstract:
1. A powder coating material system, comprising: an applicator; a first powder coating material supply and a second powder coating material supply; a pump having a pump inlet to transport powder material from a selected one of said first and second powder coating material supplies and a pump outlet to supply powder coating material to said applicator; a powder coating material changer having a first inlet connected to said first powder coating material supply, and a second inlet connected to said second powder coating material supply, said powder coating material changer having a common feed passage selectively in flow communication with each of said first and second inlets, said common feed passage has a changer outlet connected to said pump inlet of said pump, each inlet connecting to said common feed passage through a respective port formed in a wall of said common feed passage, a first valve associated with said first inlet and a second valve associated with said second inlet, each valve operable to prevent flow between its associated inlet and said common feed passage by blocking said port, said pump comprising a cylindrical pump chamber, said pump chamber alternately being put under negative and positive pressure, said pump having a supply mode wherein when said pump chamber is put under negative pressure, air and powder coating material are sucked through said pump inlet into said pump chamber from said selected one of said powder coating material supplies through said powder coating material changer common feed passage in a first direction, and when said pump chamber is put under positive pressure, air and powder coating material are pushed out of said pump chamber through said pump outlet to said applicator; said pump also having a purge mode wherein when said pump chamber is put under positive pressure, air and powder coating material are pushed out of said pump chamber through said pump inlet to flow through said common feed passage in an opposite direction from said first direction to purge powder coating material from said common feed passage, and air and powder coating material are pushed out of said pump chamber through said pump outlet to said applicator to purge powder coating material from said applicator.