1869. Granville (1041).—Substitution of a second beater roll for the stationary bed-plate, the knives being set spirally round the roller.
1869. Newell (2905).—Weight of the beater roll counterpoised to allow of the exact regulation of the pressure on the stuff in the beating engine.
1870. Rose (997).—An intercepting plate fixed to the cover of the beating engine which causes that part of the stuff which was usually carried right round by the roll to fall back behind the backfall.
1870. Bentley and Jackson (1633).—A beater roll having the same width as the engine, and provided with a cover fitted with a pipe which conducted the material back to the front of the roll.
1871. Patton (1336).—Bottom of beating engine curved in order to prevent the stuff settling or accumulating at any portion of the machine.
1872. Salt (1901).—A beating engine of usual type, but having two beater rolls and two drum washers, one pair in each of the two channels.
1873. Gould (769).—A curious engine with horizontal shaft having a circular disc at the lower end, fitted with knives on the under-surface, which are in contact with fixed knives lying at the bottom of the vessel. The circulation of the pulp is effected by the centrifugal force generated.
1873. Martin (3751).—A beating engine with two rolls in the same trough, the first roll working in conjunction with a smooth surfaced beating roll, the other being in contact with a bedplate of the usual type, the object of the first roll being to partially disintegrate the material without danger of choking.
1874. Johnstone (3708).—A pulping engine in which the rubbing action of two grindstones one upon the other is utilised as a means of beating.
1876. Gardner (307).—A beating engine in which the beater roll is conical in shape, working vertically in contact with the bottom of the beating engine, which is also conical in shape, the engine itself being circular.