GB216805A - Process and apparatus for coating or impregnating road stone or other material - Google Patents

Abstract

216,805. Burn, J. F., Lancaster, J. S., and Langford, H. Dec. 5,1922. Coating-machines.-In a process for coating or impregnating stone or other material with tar or other liquor, the dried stone &c. is charged in equal quantities into perforated buckets 28 pivotally mounted on an endless chain 29, the motion of which is interrupted at regular short intervals to facilitate charging, the full buckets being passed through the liquor tank 33. As the buckets rise from the tank, the superfluous liquor drains back to the tank, and later the buckets are tipped to discharge the coated material. In the tar-macadam plant shown, the buckets are driven from a power shaft 9 through a gear-box 35 which receives a continuous drive and gives out an intermittent drive. The stone, after leaving the drying drum 1, is raised to a hopper 4 the base of which is fitted with a revolving tray 10 and a fixed vane 11 for delivering the stone through an aperture in the rim of the tray into a fixed measure 12. During the period of rest of the buckets 28, a feed-box 15 is reciprocated between the measure 12 and the buckets 28 by the cam gear 22. The arrangement is such that discharge doors 13 on the measure 12 are automatically opened when the box 15 moves below the measure 12, and similar discharge doors 18 on the box 15 is automatically open when the box is over a bucket 28. The buckets are tipped by the engagement of cams 42 thereon with a fixed inclined rail 43.