Method for selective removal of materials present in one or more layers on an object, and apparatus for implementation of this method

Method for selective removal of materials present on an object in one or more layers by surface abrasion, by projection onto the surface of this object of a moving fluid composed of a gas and solid particles conveyed by said gas, including the step of:

• forming a single same reserve of solid particles from at least two primary reserves of different respective basic bracket of granulometry,
• taking solid particles from this single same reserve and incorporating them in a stream of gas to form the moving fluid,
• directing this moving fluid through a conduit to an outlet nozzle situated in the immediate vicinity of the surface of the object,
• recovering at least a part of the solid particles after they have struck the surface of the object,
• directing the recovered particules to the single same reserve,
• measuring the average granulometry of these recovered particles on their arrival in the single same reserve and,
• either only by removal of solid particles from the recovered particles, or only by addition of other solid particles taken from at least one primary reserve, or by combining such a removal and such an addition, adjusting, in the single same reserve, the average granulometry of the particles to be taken, depending on the granulometry of the particles present in the single same reserve after incorporation of the recovered particles, in order to control the average granulometry of the particles to be drawn from the single same reserve, to the nature of the object to be treated and/or the state of its surface.