Surface treatment of e.g. decorative pin cones - by subjecting to stream of water vapour to whiten the surface

摘要

A process and equipment for decorating the surfaces of fir cones etc. is new. A batch of fir cones is placed inside a permeable container, e.g. a jute sack or wire mesh cage. Steam is injected and diffused into the container until the natural resin of the cones becomes liq. A whitening agent is added to the steam, e.g. sulphuric acid, conc. hydrogen, chlorine or other halogen. The whitening agent is pref. drawn into the steam line via the inlet branch of an ejector pump. The process is complete in only a few minutes. The moisture makes the cones swell slightly which is desirable to their appearance.