Patent ID: 8425838

Claim:
An oxygenator comprising: a housing; a hollow fiber membrane bundle comprised of a plurality of gas-transmissive hollow fiber membranes each possessing a lumen, the hollow fiber membrane bundle comprising an outer peripheral surface defining an outer circumference of the hollow fiber membrane bundle; a gas inlet port communicating with the lumens of the hollow fiber membranes to introduce an oxygen-containing gas into the lumens; a gas outlet port communicating with the lumens of the hollow fiber membranes; a blood inlet port communicating with a blood flow path that is exterior of the hollow fiber membranes in the housing; a blood outlet port communicating with the blood flow path; a filter member positioned in the housing in surrounding relation to the outer peripheral surface of the hollow fiber membrane bundle; the filter member comprising a warp thread and a weft thread, the warp thread and the weft thread both being arranged so as not to be parallel to a plane that is perpendicular to a longitudinal axis of the filter member, and the filter member possessing circumferential elasticity allowing an inner circumference of the filter member to be increased from a natural non-expanded state prior to placement on the hollow fiber membrane bundle to an expanded state in which the inner circumference of the filter member is increased when placed on the hollow fiber membrane bundle by being stretched in a direction about the inner circumference of the filter member; and the inner circumference of the filter member in the natural non-expanded state being less than the outer circumference of the hollow fiber membrane bundle.