Lance for spraying a dry concrete and its associated moistening collar that allows the dry product to be moistened at high pressure during the spraying operation, notably applicable for repair of refractory linings

摘要

A lance (1) for spraying a dry refractory concrete comprises a pipe (3) carrying water under pressure and some pipes (2, 5) for the pneumatic conveying of dry product and humidified product, as well as a water box (4), incorporating a moistening collar (12). This collar (12) includes four to eight water circulation openings, essentially perpendicular to the circulation axis (10) of the product and each having a diameter between 0.8 and 1.2 mm. The lance (1) also incorporates some means for putting the water under a pressure of at least 8 bars. The method of using this lance for spraying refractory concrete consists of mixing the water with a dry product made up notably of ultrafine particles, a dispersant and a hardening accelerator. The mixture is effected with a volumetric water content of less than 25%. The moistening collar used in association with the lance is also claimed