NOZZLE FOR ISSUING SOLID CARBON DIOXIDE PARTICLES WITH AN AXIALLY DISPLACABLE VALVE MEMBER; APPARATUS TO COOL A WELDED WELDING AREA WITH SUCH NOZZLE; WELDING DEVICE WITH SUCH COOLING DEVICE.

摘要

A nozzle (16) for emitting solid particles of carbon dioxide, whose nozzle comprises an inlet (28) for receiving liquid carbon dioxide, a nozzle opening (32) from which solid carbon dioxide particles flow from the nozzle, a conduit (26) extending between the inlet (28) and the opening (32) of the nozzle, the conduit (26) having a converging section (36) and a diverging section (38), and an elongated valve member (42) axially movable, located inside the conduit (26) to control the cross section of the flow of carbon dioxide through the conduit (26), the valve member (42) having a first (56) and a second (60) convergent parts (56, 60), in which the second convergent part (60) of the valve member (42) controls the convergent section (36) of the conduit (26) when the valve member (42) is in closed position and the duct (26) comprises a throat (40) located between the convergent section (36) and the divergent section (38), characterized in that the valve member (42) has a substantially cylindrical part (58) located between the first (56) and the second (60) convergent parts (56, 60) so that, in use, the cylindrical part (58) is located between the throat (40) and the opening (32) of the nozzle when the valve member (42) is in the closed position.