Product Description

Vacuum evaporation is one of the most commonly used methods for deposition of functional films on to various substrates. The vacuum is used to allow vapor particles to deposit directly on to the substrate, where vapor particles condense back to a solid state, forming a functional coating. The vacuum evaporation process involves two basic stages: the evaporation of a functional material and the condensation on the substrate. In high-vacuum evaporation, electrical heating or electron beam heating is used to melt, gasify and evaporate the coating materials. The vapor of the coating material then travels to the surface of the substrate and gradually cools, a thin film layer of good quality is finally formed (Jankowski and Hayes, 2004). Vacuum is used to prevent the collision of the evaporated particles with the background gas or other unwanted particles. Evaporated functional materials deposit on to the surface of the substrate.

These work on the basis of the "thermo-siphon"  principle. As the feed enters the bottom of the heating tubes, steam begins to form. Because of the ascending force of the steam produced during boiling, liquid and vapors flow upwards in parallel flow.