Abstract: Apparatus for effecting clarification of liquid having particulate material entrained therewithin includes a filter screen and a filter-cleaning device disposed adjacent thereto operable for removing particulate material from the filter screen which has been deposited or accumulated thereon from a particulate-laden liquid discharged onto the filter screen. The filter-cleaning device includes a dispenser which is selectively positioned, in an automatic manner, relative to the filter screen to direct a fluid flow against the filter screen at variable locations thereon to impart movement to the retained particulate material relative to the filter screen. Additionally, the filter-cleaning device of the present invention includes a plurality of nozzles, which form the dispensing device, mounted on a carriage which is operable for carrying the dispensing device so that the nozzles will be presented over the filter screen in a selective, reciprocally shifting manner.

Abstract: A log centering apparatus and method are described employing an optical log scanner for determining the longitudinal axis of the log for optimum wood product production by transmitting light to detectors through the space between the side of such log and reference edge members. The detectors each include a linear array of photosensitive diodes which are electronically scanned to take a reading. Before scanning, rough centering arms clamp the log and its opposite ends are engaged by rotation spindles. The log may be rotated intermittently or continuously during scanning to measure at different angles the distance between the reference edge and the surface of the log at a plurality of points spaced longitudinally along the log. These distance signals are fed to an electronic computer to compute the optimum yield axis of such log.