A body, or stack of bodies, made of timber or of other organic fluid-permeable material is impregnated with an impregnant by introducing the body or stack into a receptacle of fluid-impermeable material through an opening therein, the flexible receptacle being supported by and secured (e.g. by springs)...http://www.google.com.au/patents/US4156043?utm_source=gb-gplus-sharePatent US4156043 - Impregnation of fluid-permeable bodies
