THE MUD SCRAPERS on the three rotary mud filters at Racecourse Mill are of varying
designs and scraper lengths with no adjustments to scraper angle. The scraper frames
are also fabricated from mild steel and are prone to excessive corrosion due to the hot
wet environment. As the pivot points and scraper blades wear, the blade angle presented to the screen changes and compromises the efficiency of the scraper and its ability to scrape the mud from the filter drum. This can lead to excessive blinding of the filter screen and a loss in effective filter area, which increases mud loss. The scraper blades are difficult to access and require the filter to be shutdown when changing blades. To overcome these problems the filter scrapers need to be a standard size and design and made from a non-corrosive material and be fully adjustable to optimise the blade angle presented to the screen. In collaboration with Consolidated Plastics & Epoxy a polyethylene mud scraper frame was designed, fabricated and installed on No. 3 filter at Racecourse Mill. This paper outlines the design considerations of operator safety,
reduced screen blinding, low maintenance and operational experiences with the new
mud scraper assembly.