Method for impregnating a fibrous base material with a substantially

Abstract

A method and apparatus for impregnating a fibrous base material with a varnish liquid, wherein the so-impregnated base material is substantially air free. A base material is passed under the surface of and through a supply of low-viscosity liquid such as to impregnate the base material with the low-viscosity liquid and displace air from the base material so as to provide a substantially air-free base material. The air-free base material is passed through an entrance for and into a syphon. An inert gas is supplied to the syphon so as to maintain an inert gas atmosphere therein sufficient to maintain the air-free condition of the base material. The air-free base material is then passed through an exit of the syphon and under the surface of and through a supply of varnish liquid sufficiently to displace the low-viscosity liquid from the air-free base material and impregnate the air-free base material with the varnish liquid.