GB416967A - Improvements in or relating to the mixing of plastic compositions and coating of pipes and the like therewith - Google Patents

Abstract

416,967. Coating pipes. STAVELEY COAL & IRON CO., Ltd., Hollingwood, near Chesterfield, and FABRY, R., 7, Devonshire Road, Totley Rise, both in Derbyshire. Jan. 9, 1934, No. 864. [Class 99 (ii).] In a machine for coating pipes or the like with plastic material, e.g. a mixture of pitch and asbestos, of the kind comprising means to revolve the pipe, means to feed the plastic material on to the pipe and means to move the pipe and the feeding means relatively to one another in the longitudinal direction of the pipe, one or more strickling plates are located adjacent to the pipe surface and are so inclined to the axis as to wipe the applied plastic material forwardly along the pipe during its rotation. The pipe 49 is mounted between a headstock 44 and a tailstock 45 on a carriage 41 carried by wheels 42, 43 running on rails 65, and is provided with end plugs 50, 51 held in place by a rod passing through the tube and adapted to be engaged by conical bosses 55, 56 on the head and tail stocks. The pipe is rotated from a motor 60 through a chain drive 59 and a pinion which engages a spur wheel 57 on the boss 56. The carriage 41 is driven longitudinally by a reversible motor 61 through a reducing gear 62 and a chain 63 engaging one of wheels 43. The wheels 43 are double flanged and the wheels 42 unflanged to facilitate accurate guiding of the carriage. The means for supplying the coating material comprises a jacketed heated vessel 11 for the liquefiable constituent, e.g. pitch, a shoot 25 for the solid constituent, e.g. asbestos, and a jacketed heated mixing chamber 22 having an outlet pipe 34 leading to a valve controlled nozzle 36 situated above the pipe 49. The vessel 11 and the chamber 22 are provided respectively with stirrers 14, 31, and a conveyer 35 is situated in the outlet pipe 34. A byepass 39 conducts excess material unable to pass the valve 37 back to the chamber 22. Hot gases from the jacket 17 surrounding the vessel 11 are conducted through a conduit 19 to the chamber 28 beneath the shoot 25 and pass through the material as it passes over the screen 26. The strickle plates 72, 73 are carried by slides engaged by guides 71, are retracted by springs 74, and are advanced against stops by hydraulic cylinders 75 each provided with a screwed rod 76 engaging a lug 77 on the slide. The strickle plates are electrically heated, are inclined downwardly towards the pipe surface, e.g. at an angle of about 45‹ to the vertical tangent plane to the pipe when the centre of the plates is level with the pipe axis, and are inclined longitudinally to the axis of the pipe at such an angle that the line of contact lies approximately at right angles to the helical path traced over the coating by the plates.