Process and apparatus for coating

A method of coating one or more workpieces in a coating job batch with a particular coating material, using a coating system including a coating material supply unit that supplies said coating material, a main supply line that has an inlet end connected to said coating material supply unit and that extends away from said coating material supply unit, plural coating material atomizers respectively connected to said main supply line by respective branch connections successively spaced from one another along said main supply line, and a pig arranged and dimensioned to be movable in and along said main supply line;

• said method comprising the steps:
• a) determining a required quantity of said coating material that will be required for coating said one or more workpieces;
• b) determining a residual quantity of said coating material that will remain residually in at least one of said atomizers and said branch connections;
• c) determining a total quantity of said coating material as a sum of said required quantity and said residual quantity, wherein said total quantity is independent of a volume capacity of said main supply line;
• d) metering and supplying only said total quantity of said coating material from said coating material supply unit through said inlet end into said main supply line;
• e) at a completion of said step d), positioning said pig in said main supply line at a tail end of said total quantity of said coating material in said main supply line;
• and
• f) opening one or more of said branch connections to enable flow communication therethrough to one or more of said atomizers respectively connected thereto, and pushing said pig with a pushing medium through said main supply line in a direction from said inlet end toward said branch connections, whereby said pig pushes said coating material in said main supply line thereby pushing and atomizing said required quantity of said coating material out through said one or more of said atomizers, whereas said residual quantity of said coating material remains residually in at least one of said one or more branch connections and said one or more atomizers.