System for electrostatic application of conductive coating liquid

Apparatus for electrostatic application of relatively conductive coating liquid, comprising:

• first and second application systems, each said application system including a grounded coating liquid supply means, reservoir means, and means for transferring coating liquid from said coating liquid supply means to said reservoir means while electrostatic application of coating liquid is occurring and while maintaining electrical isolation between said reservoir means and said coating liquid supply means;
• an electrostatic spray device coupled to an interruptable high voltage supply;
• first application system isolator means coupled between said first application system reservoir means and said spray device and operable between a first state establishing a coating liquid flow path from said reservoir means to said spray device and a second state interrupting said flow path and electrically isolating said reservoir means from a high voltage at said spray device;
• and
• second application system isolator means coupled between said second application system reservoir means and said spray device and operable between a first state establishing a coating liquid flow path from said reservoir means to said spray device and a second state interrupting said flow path and electrically isolating said reservoir means from a high voltage at said spray device.

Apparatus for electrostatic application of relatively conductive coating liquid, comprising:

• first and second application systems, which said application system including a grounded coating liquid supply means, reservoir means, and means for transferring coating liquid from said coating liquid supply means to said reservoir means while electrostatic application of coating liquid is occurring and while maintaining electrical isolation between said reservoir means and said coating liquid supply means;
• an electrostatic spray device coupled to an interruptable high voltage supply;
• first application system isolator means coupled between said first application system reservoir means and said spray device and operable between a first state establishing a coating liquid flow path from said reservoir means to said spray device and a second state interrupting said flow path and electrically isolating said reservoir means from a high voltage at said spray device;
• and
• second application system isolator means coupled between said second application system reservoir means and said spray device and operable between a first state establishing a coating liquid flow path from said reservoir means to said spray device and a second state interrupting said flow path and electrically isolating said reservoir means from a high voltage at said spray device,
• including means for operating said apparatus so that said first and second application systems provide coating liquid to said spray device one at a time, and so that when one application system is providing coating liquid its means for transferring is transferring coating liquid from its coating liquid supply means to its reservoir means while maintaining electrical isolation therebetween and its application system isolator means is in said first state to establish a flow path for coating liquid from its reservoir means to said spray device, while at the same time said application system isolator means of the other application system is in said second state to electrically isolate said other application system reservoir means from a high voltage at said spray device.

Apparatus for electrostatic application of relatively conductive coating liquid, comprising:

• first and second application systems, each said application system including a grounded coating liquid supply means, reservoir means, and means for transferring coating liquid from said coating liquid supply means to said reservoir means while electrostatic application of coating liquid is occurring and while maintaining electrical isolation between said reservoir means and said coating liquid supply means;
• an electrostatic spray device coupled to an interruptable high voltage supply;
• first application system isolator means coupled between said first application system reservoir means and said spray device and operable between a first state establishing a coating liquid flow path from said reservoir means to said spray device and a second state interrupting said flow path and electrically isolating said reservoir means from a high voltage at said spray device;
• and
• second application system isolator means coupled between said second application system reservoir means and said spray device and operable between a first state establishing a coating liquid flow path from said reservoir means to said spray device and a second state interrupting said flow path and electrically isolating said reservoir means from a high voltage at said spray device,
• wherein said transferring means of each said application system comprises:
• a plurality of isolator means, each said isolator means having passage means of electrically insulating material extending between an inlet to and an outlet from said passage means and means for mechanically displacing, without the use of solvent for the coating liquid, from said passage means and passage means surface and through said passage means outlet coating liquid introduced to said passage means through said passage means inlet, so that each said isolator means is electrically insulating between its inlet and outlet upon mechanical displacement of coating liquid from its passage means and passage means surface,
• said plurality of isolator means of each said application system being connected with their passage means in series between said coating liquid supply means and said reservoir means of their associated application system,
• and including means for operating said mechanical displacing means of said plurality of isolator means of each said application system, such that for each application system coating liquid is always mechanically displaced from the passage means and passage means surface of at least one of its plurality of isolator means at all times when the high voltage is present and said application system is providing coating liquid to said spray device, whereby electrical isolation is always maintained between said reservoir means and said grounded coating liquid supply means of such application system.

A system for electrostatic application of relatively conductive coating liquid, comprising:

• an electrostatic sprayer coupled to an interruptable high voltage supply;
• grounded coating liquid supply means;
• reservoir means;
• first isolator means having passage means coupled with its passage means in series with a first coating liquid flow path between said coating liquid supply means and said reservoir means and operable between a first state establishing a path through said passage means and a second state interrupting the path through said passage means and providing electrical isolation in said first flow path, without use of solvent for the coating liquid, between said coating liquid supply means and said reservoir means;
• and
• second isolator means having passage means coupled with its passage means in series with a second coating liquid flow path between said reservoir means and said spray device and operable between a first state establishing a path through its passage means and a second state interrupting the path through its passage means and providing electrical isolation in said second flow path, without use of solvent for the coating liquid, between said reservoir means and said spray device.