Method of removing a filter medium from a filter vessel, and evacuating device for use in such method

摘要

In filters of the type comprising a filter vessel (52) having a restricted access opening (58) providing access to the inside of the vessel, and a bed of particulate filter medium (54) in the vessel, the removal of filter medium from the vessel for purposes of cleaning or replacing the medium is normally a laborious and time-consuming operation. In accordance with the invention the filter medium is removed from such a vessel by inserting an evacuator tube (12) having a inlet opening (16) at one end thereof via the access opening into the vessel so that said one end penetrates into the bed of filter medium; fluidising the filter medium in the region of the inlet opening by means of a primary fluid jet (62); and evacuating the fluidised filter medium from the filter vessel via the evacuator tube, through suction created by means of a secondary fluid jet (66) disposed at or near the inlet opening and being directed into the evacuator tube.