| 摘要 |
Parent patent described a tractor with a scraper to skim off the surface layer in filter basins of drinking water purificn. systems. A drive shaft at the side of the scraper is now fitter with a fettling wheel with flexible radia flails which clean the basin sides and move along the bottom in the direction towards the scraper device. This saves having to clean up the corners and sides of a filter basin by manual labour because the tractor-mounted scraper device could not reach them. |
