DEVICE FOR SURFACING BY A SPRAY OF ABRASIVE SUBSTANCE

摘要

The proposed device for surfacing by a spray of abrasive substance is intended for cleaning of surfaces prior to painting, and it can be applied as a nozzle of sandblaster. It contains the body (3), air Laval nozzle (1) and the abrasive feeding nozzle (2) that is placed on the axis of air Laval nozzle (1). The novelty of an invention is characterized in that the feeding nozzle of the abrasive suspension is installed inside the Laval nozzle, both said nozzles forming altogether an annular channel of a hypersonic profile, the exit section of said channel being disposed in a plain of widening supercritical part of a Laval nozzle. Alternatives of realization of an invention are the following: the abrasive suspension feeding nozzle is shaped either as a cylindrical nozzle or as a Laval nozzle, or as a Venturi tube; the abrasive suspension feeding nozzle on an input end is bridged with the cylindrical chamber which form with the body of the device an annular channel, the wall of said chamber being provided with holes cut at straight or acute angle with regard to transport direction of the abrasive flow. Such construction of the device ensures that the abrasive suspension is delivered at the centre of spray and the high-velocity annular flow of air is delivered at exterior contour of nozzle. Such pattern of a spray results in magnification of an operating range of the device and derives high speed of an abrasive. The general view of the device according to an invention, in case the abrasive suspension and air are delivered by one and the same channel or sleeve, is shown in a figure 1.