Apparatus and a method are provided for isolating an electrostatic sprayer
from an electrically grounded coating product distribution circuit
connected thereto. The apparatus includes an electrostatic sprayer
carried by a maneuverable robot arm, the sprayer capable of spraying an
electrically conductive coating product such as water-based paint onto a
workpiece passing in adjacent proximity thereby, on command. The coating
product is supplied from a remote source of supply through at least one
distribution circuit connected to the sprayer. The apparatus includes
therein, carried by the robot arm, an electrically insulative storage
tank for the coating product in valved fluid communication with the
sprayer. The insulated storage tank is connected to and positioned
downstream from a length of electrically insulative supply conduit
connected to the distribution circuit and also carried by the robot arm.
This conduit includes a cleaning mechanism for cleaning a portion,
including all, of this length of supply conduit, in situ, after filling
of the storage tank with coating product and before spraying. In this
way, substantially all of the conductive coating product is removed from
the portion of supply conduit, thereby completely isolating the sprayer
electrically from the distribution circuit. The cleaning mechanism is
preferably a chemically resistant plunger fitted in the conduit and
adapted to reciprocally traverse the length of the conduit on command,
effectively wiping it clean of coating product and thereby galvanically
isolating the sprayer from the distribution circuit during the actual
spraying operation.
