An improved pressurized filter apparatus, which filters fluid axially through filter elements formed with wound layers of tissue, includes at least one fluid collector with at least one passageway for filtered fluid to flow from the adjacent filter elements inwardly into the centrally located flow path to the filter exit port. The passageways are formed by upraised ridges which space the filter element exit ends from the substantially flat portion of the collector. Annular ring portions project axially from the flat portion of the collector into the adjacent filter element exit ends to form a first seal which separates unfiltered fluid from filtered fluid. A rigid outer retention ring projects axially from the outer perimeter of the collector flat portion, and includes one inside surface for each adjacent filter element which abuts against the periphery of the adjacent filter element to form a second seal which further ensures separation of unfiltered fluid from filtered fluid. When filter elements are arranged so that the intake ends of two filter elements face each other, the filter apparatus also may include a directional flow control element which forms a third seal with each of the two filter element intake ends to prevent the unfiltered fluid from bypassing the filter elements by leaking into the centrally located flow path. The pressurized axially fluid filter apparatus also may include at least one substantially non-expandable sheath, each of which surrounds one collector and encloses the peripheries of the adjacent filter elements to thereby limit expansion of the filter elements due to water adsorption.
A fluid collector for use in a fluid filter includes a substantially flat portion having two sides of which at least one faces a filter element from which filtered fluid is received, a centrally disposed opening adapted to allow the centrally located flow path to pass axially therethrough, and at least one slot which forms a passageway for filter fluid to flow from the filter elements to the receiving ports into the centrally located flow path. The fluid collector also includes ridges which project axially from at least one side of the substantially flat portion to maintain the filter element ends in parallel spaced relationship to the substantially flat portion. The filter collector further includes a continuous annular ring portion which projects axially from the outer perimeter of the flat portion on at least one side thereof to extend into each adjacent filter element exit end between those layers of filter element tissue which are located inwardly a few layers from the periphery of each filter element, so that a seal is formed which separates filtered fluid from unfiltered fluid.