Method and Apparatus for Coating Elongate Members such as Pipes.

摘要

1,156,776. Coating apparatus. C. PRICE CO. 13 Feb., 1967 [20 June, 1966], No. 6800/ 67. Heading B2L. In coating the surface or a pipe or elongated member with a thermosetting synthetic resin initially in in powdered form, the surface is heated to a temperature at least equal to the minimum temperature at which the powdered resin is rendered fusible but below the minimum curing temperature of the resin, the powder is entrained in an air-stream and is discharged thereby against the surface which the latter as at the treating temperature and while the pipe or member is rotated about its longitudinal axis, whereby the resin adhers to the surface, land the temperature of the resin adhering to the surface is elevated to at least said minimum curing temperature for sufficient time to cure .the coating. Preferably the surface is cleaned prior to heating by air blasting with a particular abrasive substance and directing a fluid under pressure at the surface. With the apparatus shown, pipe 62 after being cleaned and pre-heated to approxima- 'tely 350‹F is supported for rotation and a lance 26 mounted on a carriage (12) on tracks (18) (Fig. 2 not shown) and having an electrostatic discharge head 46 is inserted through the pipe 62. resin powder is carried in a fluidized state in a reservoir on carriage (12) and is fed at the lance via conduit 42. The lance is surrounded by a jacket 28 through which cooling medium is circulated to prevent the powder fusing in the tube 26 and the jacket 28 carries guide rollers 84. The discharge lead may be such as to cause the resin carrying air stream to flow over the internal surface of the pipe in a helical or conical path as the lance moves through the pipe. The lance carriage (12) may have control arrangements to effect automatic insertion and withdrawal of the lance assembly at a desired speed and in synchronism with the delivery of successive pipes. After the coating operation the pipe is conveyed to a soaking oven where the temperature of the coated surface is raised to approximately 450‹F for curing the coating. Subsequently the external surface of the pipe may be coated' by an exterior electrostatic coater and then conveyed to a water quencher.