US 6,235,403 B1 · Process of treating wood with preservative

Abstract

A wood treatment process is disclosed in which in one aspect the wood is impregnated with a waterborne preservative such as CCA at elevated temperature and pressure. The impregnated wood and excess waterborne preservative are separated while the treatment vessel (8) is pressurized, for example by blowing the preservative out of the vessel at the treatment pressure using a pump (10). Kickback may be segregated from the wood once pressure is reduced after the separation of wood and preservative. In another aspect the wood is impregnated with a waterborne preservative and with oil, each of the impregnating steps being performed under pressure and the oil being heated. If the preservative is one such as CCA which is capable of being fixed to the wood the hot oil may enhance this as well as providing water repellency. The oil may be a process oil.

Claims42

Dependent claims

A process for treating wood with waterborne preservative, comprising the following steps:

introducing wood to be treated into a treatment vessel;
pretreating said wood by application of at least one of (a) an initial vacuum, and (b) a pressure not exceeding 150 kPa;
immersing said wood in said treatment vessel in a waterborne preservative preheated to a temperature of about 40° C. to about 90° C., at elevated pressure and at elevated temperature ranging from at least 40° C. to less than 100° C. so as to impregnate said wood with said preservative and to facilitate fixation of said preservative in said wood in a single step;
separating impregnated said wood and any excess waterborne preservative while said treatment vessel is pressurized;
and
reducing pressure in said treatment vessel.

3 more elements

Dependencies are inferred from the claim text.

Process of treating wood with preservative

Life of this patent

Process of treating wood with preservative

Life of this patent

Abstract

Claims42