A paint storage vessel is disclosed which is subdivided by flexible insulation into two interior spaces, each connected to its own distribution line and its own paint supply line. The ring main system is connected to the two distribution lines and is effected with the interposition of an electrically insulating change-over mechanism.
At least part of an electrostatic spraying installation for spraying an electrically conductive liquid product such as a coating product is grounded. The installation includes at least one intermediate storage tank that is electrically insulated from ground and at least one electrostatic sprayer device that is supplied from this intermediate storage tank. The electrostatic sprayer device is connected to a variable or switchable high-tension voltage source. The installation includes at least one electrical insulation device which incorporates a section of insulative conduit and a liquid inlet and a liquid outlet at respective ends of this conduit section. A piston movable in the conduit section scrapes its inside wall clean.
An electrical insulator device is in the form of a section of pipe for a conductive liquid. The device comprises an insulative casing accommodating a mobile assembly and an expandable pipe part is connected between one end of the casing and this mobile assembly, which carries ano-ring for scraping clean an end surface of a connection mechanism arranged in the vicinity of the second end of the casing, with which it cooperates.
An installation particularly suited to use in the automobile industry for electrostatic application of conductive coating product is partly at a high-tension voltage and partly grounded, these parts being separated by at least one temporary insulating device. The electrostatic sprayer is fed from a first storage tank insulated from ground and the latter is filled in a very short time period with coating product previously stored in a grounded second storage tank, through a temporary insulating device.
A system for electrostatic application of conductive coating liquid has a grounded primary supply of conductive coating liquid, an electrostatic spray device and a system for delivering coating liquid from the primary supply to the spray device while maintaining a high voltage at the spray device electrically isolated from the primary supply. The delivery system includes one or more electrical insulation devices, each of which has a cylinder comprising an insulative conduit having a liquid inlet and a liquid outlet. The cylinders of the electrical insulation devices are connected via their inlets and outlets between the primary supply and the spray device to deliver coating liquid from the primary supply to the spray device. Each electrical insulation device has within its cylinder a piston that is movable between the inlet to and the outlet from the cylinder to move coating liquid out of the cylinder while scraping the inside wall of the cylinder free of coating liquid, so that the cylinder becomes substantially electrically insulating between its inlet and outlet.
