Cleaning of an air filter screen of an agricultural vehicle

摘要

A method and apparatus are disclosed for unblocking a perforated rotary filter screen (14). In the invention, at least one jet of high pressure air is directed at a surface of the filter screen (14) as the filter screen (14) is rotated and the or each jet of air is moved in a direction transverse to the direction of movement of the perforations in the screen in order to cause the or each air jet to trace a spiral or helical path over the surface of the screen. The jet may be directed at the axial end face or the cylindrical wall of the filter screen.