Electrostatic coating method and apparatus

An apparatus for electrostatically coating a workpiece, comprising:

• a coating gun to which a high voltage will be applied;
• and
• an insulating separator valve mechanism for electrically separating a paint supply passage for supplying an electrically conductive paint to said coating gun into a first paint supply passage to which a high voltage will be applied and a second paint supply passage to which no high voltage will be applied, said insulating separator valve mechanism comprising:
• a first valve body connectable to said first paint supply passage through a first on/off valve;
• a second valve body connectable to said second paint supply passage through a second on/off valve;
• and
• actuating means for detachably connecting said first valve body and said second valve body to each other,
• wherein said apparatus further comprises:
• a communication hole defined when said first valve body and said second valve body are connected to each other;
• a first dump passage branched from said communication hole near said first valve body;
• a first dump valve connected to said first dump passage for opening and closing said first dump passage;
• and
• a first cleaning medium supply passage disposed near said second valve body for cleaning said communication hole through a first cleaning valve.

An apparatus for electrostatically coating a workpiece, comprising:

• a coating gun;
• a paint supply passage for supplying an electrically conductive paint to said coating gun;
• and
• an insulating separator valve mechanism for electrically separating a dump passage branched from said paint supply passage for discharging a drain liquid including the electrically conductive paint, into a first dump passage to which a high voltage will be applied and a second dump passage, said insulating separator valve mechanism comprising:
• a first connector having a first on/off valve connected to said first dump passage and having branch passages connected to a cleaning medium supply source upstream of said first on/off valve;
• and
• a second connector having a second on/off valve connected to said second dump passage,
• wherein said apparatus further comprises:
• third on/off valves disposed respectively in said branch passages for connecting a liquid medium supply source from a junction between said first connector and said second connector to said second dump passage while said first connector and said second connector are connected to each other.

An apparatus for electrostatically coating a workpiece, comprising:

• a coating gun;
• an insulating separator valve mechanism for electrically separating a paint supply passage for supplying an electrically conductive paint to said coating gun into a first paint supply passage connected to a paint supply source and a second paint supply passage to which a high voltage will be applied, said insulating separator valve mechanism comprising:
• a first connector having a first on/off valve connected to said first paint supply passage;
• and
• a second connector having a second on/off valve connected to said second paint supply passage;
• and branch passages connected to a cleaning medium supply source upstream of said second on/off valve, said first and second connectors being connected respectively to said branch passages,
• wherein said apparatus further comprises:
• an openable third on/off valve connected to one of said branch passages;
• and
• a closable fourth on/off valve connected to another of said branch passages,
• wherein when said second on/off valve is closed, said openable third on/off valve and said closable fourth on/off valve are connected to each other to expel air trapped in a junction between said first and second connectors into a portion of the branch passages under pressure of the electrically conductive paint supplied from said first paint supply passage.