Abstract:
The method for flame coating tubular elements provides for arranging a said tubular element (2) to be coated at a coating station, providing an applicator unit (3), operating in the coating station, in an inactive configuration, spaced from the tubular element (2), the applicator unit (3) carrying at least one thermoplastic powders flame applicator device (4) and being alternatively operable between the inactive configuration and an active configuration, approached radially to the tubular element (2). After having brought the applicator unit (3) towards the tubular element (2), the method provides for operating the same unit (3) in the active configuration, so as to peripherally engage the element (2) itself. The applicator device (4) is turned on, the thermoplastic powders are fed and the applicator device (4) is operated in motion around and/or along the tubular element (2) so as to flame coating it with a controlled flow of thermoplastic powders.
Abstract:
The method for spraying thermoplastic powders provides to feed a flow of compressed air and/or nitrogen and a liquefied petroleum gas through respective separated discharge chambers (9, 12), shaped inside a mixing device (1) of a spray gun (100), the separated discharge chambers (9, 12) being in communication with a mixing chamber (15). Then a flame is ignited at the mixing chamber, through a flame ignition device (30) connected with the gun (100), said device comprising a spark ignition device (31, 310), and a conductor element (32) associated with the mixing device (1) and connected with the spark ignition device (31, 310). The thermoplastic powders are mixed with a transport inert gas, and fed through a further discharge chamber (7) communicating with the mixing chamber (15). Then the spray gun is operated to spray the thermoplastic powders through the flame onto the surface of the article to be coated, to cause the melting of the same powders.
Abstract:
The method for flame spraying thermoplastic powders provides to heat the article to be coated at a suitable working temperature and to feed the said thermoplastic powders, transported by an inert gas, a flow of compressed air and a flow of liquefied petroleum gas through respective separated discharge chambers (7, 9, 12), shaped inside a mixing device (1) of a spray gun. The thermoplastic powders are then projected, in a resulting flow (30), on the heated surface of the article to be coated, to determine the melting of the same powders at their contact with said heated surface. At least one couple of flows (31, 32) of compressed air is sprayed converging towards the resulting flow (30) flowing out of the mixing device (1), giving the resulting flow (30) a substantially flattened fan shape.