Pressure filter with a back-flushing head exerting a uniform contact pressure

A pressure filter comprising:

• a housing defining a fluid compartment, said housing having a fluid inlet communicating with said fluid compartment;
• means forming at least one filter surface in the fluid compartment, said filter surface having a plurality of apertures, one side of the filter surface being restricted by the fluid compartment and another side of said filter surface being restricted by a filtrate compartment formed in said housing and having a filtrate outlet;
• a backwashing unit comprising a radially extending backwash head extending from a central support to a radially outer portion of said filter surface, said backwash unit further including means for rotating the backwashing head to sweep over the filter surface and sealing a part of the filter surface with respect to the fluid compartment, the backwashing head defining a backwashing compartment having at least one suction chamber having a slot-like aperture opened to the filter surface and having connected thereto a reject drain;
• and
• a resiliently acting pressure means associated with the backwashing head for pressing a radial outer portion of the backwashing head axially towards the filter surface, the pressure means being formed by at least one biased radial spring strut supported centrally at the central support and at a radial end portion of the backwashing head.