METHOD FOR REMOVING OVER-SPRAYED HYDROCARBON LAYERS Russian patent published in 2018 - IPC B08B7/00 

FIELD: technological processes.

SUBSTANCE: invention relates to the technology of cleaning vacuum chambers and other elements in a vacuum located in areas difficult to reach for cleaning, from over-sprayed hydrocarbon layers and can be used in installations with elements from carbon materials facing plasma and in process units. Essence of the method is to create a vacuum in the working volume, ignition of HF plasma in the atmosphere of the working gas at a pressure sufficient to generate the plasma. Used to remove the over-sprayed hydrocarbon layers, high-frequency plasma is created with an electron beam in a longitudinal magnetic field of at least 1,000 G, directed at the receiving electrode with a secondary emission coefficient > 1. In this case, the bias voltage required for the transition of the discharge to the self-oscillating mode is applied to the receiving electrode. After the transition of the discharge to the self-oscillating mode, high-frequency currents are induced in the adjacent walls. And in the cavities and crevices there are strong variable fields that promote the appearance of chemically active radicals both in the areas adjacent to the walls, and in the gaps and areas shaded from the plasma. Interaction of reactive radicals with hydrocarbon films leads to the appearance of volatile compounds and, accordingly, surface cleaning.

EFFECT: invention provides enhanced opportunities for the removal of hydrocarbon films in places where it is practically impossible to do so using the currently known technologies; wherein the process can be used when there is a need for cleaning at a low pressure of around 10^-1–10^-2 Pa.

1 cl, 5 dwg