Abstract: In an apparatus for filtering and separating fluids by reverse osmosis or by micro-, ultra-, and nano filtration, including a plurality of spaced planar filter elements arranged in stacks in spaced relationship so that their surfaces can be contacted by the fluids for the collection of permeate from the fluids within the filter elements, at least one draining rod having a central draining passage extends through the stack of filter elements and has openings disposed in each filter element for collecting the permeate from the respective filter elements, and a vacuum generating means is connected to a permeate discharge which is in communication with the draining rod passages for generating a vacuum in each filter element.