A filter device has a filter housing, which is intended to contain a liquid
to be filtered and in which at least one filter rod is arranged. The
filter rod is composed of annular washers, which are arranged in a stack
on a core formed with openings and which are so closely packed that
particles in the liquid adhere to the periphery of the washers when the
liquid is caused, from the outside, to pass between the washers into the
core for filtration. The filter device has a gas supply member, which is
intended to inject a gas flow into the liquid in the filter housing.
In a method of cleaning a filter rod for filtering a particle-containing
liquid in such a filter device, a gas flow is injected into the liquid in
the filter housing so that a particle sock, which is formed on said filter
rod of particles in the liquid, is detached from the filter rod and
disintegrated.
