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.