Abstract: A machine for filtering particles, in particular magnetically attractable particles, from a liquid comprises a housing having a vessel, a weir in the vessel subdividing same into an elongated treatment compartment having a predetermined compartment length and an outlet compartment, this housing being formed in the treatment compartment with a sump, and an inlet for introducing a liquid to be cleaned into the treatment compartment and an outlet for withdrawing liquid from the outlet compartment. In addition the apparatus has a carriage displaceable longitudinally on the vessel above the treatment compartment and suspending a vertical carriage frame in the treatment compartment, an array of horizontally extending spaced magnetic bars carried on the carriage frame in the treatment compartment, with the bars each having a bar length measured parallel to this treatment compartment that is substantially less than the compartment length.