GB717475A - Process for depositing varnish on conductive metallic or non-metallic surfaces - Google Patents

Abstract

<PICT:0717475/III/1> <PICT:0717475/III/2> <PICT:0717475/III/3> An apparatus for depositing electrically-charged varnishes or the like according to the parent Specification is arranged to comprise heating means whereby varnish or the like, solid at ordinary temperatures, may be liquified so as to flow through, and out of the mouth of, a nozzle without forming a plug in the said mouth. The nozzle 1 and tube 2 through which the coating material 3 is fed, Fig. 1, may be surrounded by an insulating shell 4 that shields a heating electric resistance 5. The nozzle 1 and feed reservoir 8, Fig. 2, may be encompassed by a jacket 11 through which flows a heating fluid, such as a silicon oil. In another example the reservoir may be electrically heated while the nozzle is heated as in Fig. 2. The molten material may be sent into the nozzle from the reservoir by a pump of the type where a plastic tube is caused to collapse by a roller the tube being heated by a heated fluid circulating through another tube concentric with the first tube. Another apparatus which may be used is shown in Fig 5, where the nozzle 1 is connected to a pump body 31, by a ball valve 33, in turn connected to the resevoir 8, by another ball valve 32. The pump body 31 contains a yieldable member 34 of the bellows or sylphon type, which may be deformed by a liquid under pressure delivered by a pump 36. The nozzle and pump body 31 are heated by a fluid circulating in an outer envelope 39.