High surface to volume structure and method of generating same
AssigneeBaxter Travenol Laboratories, Inc.
InventorRonald J. Leonard
Life of this patent
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Abstract
A filter assembly and element are disclosed herein for use in filtering biological fluids. The assembly includes a variable volume housing within which is positioned a cylindrically-shaped, high surface area filter. During operation, the housing volume is changed, but the surface area available for filtration remains substantially constant. This permits the filter to be operated with low priming volumes and also to effectively reduce gas bubble entrapment in the filter. A method of making the element and a method for operating the filter assembly are also disclosed.
Claims13
A filter assembly for use in filtering biological fluids which comprises:
- an expandable and contractible bellows-configurated housing having a fluid inlet and a fluid outlet;
- a cylindrically-shaped, high surface area filter element positioned within and cooperatively associated with said housing to filter fluid flowing through said housing between said inlet and said outlet, said filter including an elongated sleeve of filter material and a coil-shaped spring positioned within and engaging said sleeve for shaping said sleeve so as to provide a high surface area for filtration, said filter element being constructed and arranged so that the surface area for filtration remains substantially unchanged as the volume of the housing is changed.
A filter assembly for use in filtering biological fluids which comprises:
- a variable volume housing having:
- first end wall means;
- second end wall means;
- expandable sidewall means, which is adapted to expand and contract upon movement of the end walls toward and away from each other so as to vary the volume of the housing;
- an inlet;
- and an outlet;
- and
- a high surface area filter element positioned within and cooperatively associated with said housing to filter fluid flowing through said housing between said inlet and said outlet, said filter element constructed and arranged so that said surface area for filtration remains substantially unchanged as the volume of the housing is changed.
A method for filtering biological fluids in a filter assembly having a variable volume housing with an inlet and an outlet and a filter element having a high surface area, cooperatively associated with said housing and positioned therein to filter fluid flowing between said inlet and said outlet, said filter constructed so that said surface area remains substantially constant as the volume of the housing is changed, said method of filtration including the steps of:
- expanding said housing;
- flowing fluid through said housing through said inlet and outlet so as to fill said housing with fluid;
- pumping said housing so as to remove entrapped gas bubbles;
- and
- maintaining said housing in the compressed position during normal operation.
A filter element for use in filtering biological fluids which comprises:
- a sleeve of filter material which includes an outer filter layer and an inner support layer bonded to said outer layer;
- coil spring means positioned within and engaging said sleeve for shaping said sleeve so as to provide a high surface area for filtration whether said spring is expanded or compressed;
- said inner support layer being bonded to said shape-sustaining spring;
- and
- said spring having a coating of polyethylene or polypropylene for cooperation in bonding said spring to said inner layer.
Dependencies are inferred from the claim text.