초록 ▼

A novel device for mass transfer across a membrane is disclosed, which is particularly suitable for use as a blood oxygenator. The novel device is of the type having a pleated, selectively permeable membrane defining first and second sets of alternating pockets for the flow of a fluid to be treated

A novel device for mass transfer across a membrane is disclosed, which is particularly suitable for use as a blood oxygenator. The novel device is of the type having a pleated, selectively permeable membrane defining first and second sets of alternating pockets for the flow of a fluid to be treated (e.g. blood) and a treating fluid (e.g. oxygen), and a discrete support screen disposed within each of the pockets of said first and second sets. Of considerable importance is the feature that the support screens are designed to be substantially interdigitated when the assembly of membrane and support screens is held as a compressed stack within the housing of the device. The novel mass transfer apparatus may be utilized as a compact blood oxygenator with excellent gas transfer rates, low pressure drops and negligible trauma to blood components.

대표청구항 ▼

1. A mass transfer device for the treatment of blood comprising: a housing; a pleated, selectively permeable membrane disposed within the housing in substantially rectangular folds defining first and second sets of alternating pockets for the flow of blood and a treating fluid; a plurality of d

1. A mass transfer device for the treatment of blood comprising: a housing; a pleated, selectively permeable membrane disposed within the housing in substantially rectangular folds defining first and second sets of alternating pockets for the flow of blood and a treating fluid; a plurality of discrete non-woven support screens having substantially the same width as said folds, with one of said screens being disposed within each of said pockets of said first and second sets, said membrane and screens being held in said housing as a compacted stack compressed in a direction normal to the substantially rectangular surfaces of said folds with the screens disposed within adjacent blood and treating fluid pockets and separated by the membrane being substantially intedigitated, and with said support screens consisting essentially of a first layer in a first plane of first strands spaced apart and substantially parallel to one another and a second layer in a second plane of second strands apart and substantially parallel to one another, said first layer and said second layer being bonded together at points of contact and said first strands beng oriented with respect to said second strands at an angle of from about 45° to 90°, and said first strands and said second strands in said blood pocket and treating fluid pocket support screens being all oriented at acute angles of from about 20° to about 70 ° with respect to the fold lines of said membrane; blood inlet and outlet means in the housing adjacent opposed ends of said stack in communication with the first set of pockets, thereby establishing overall blood flow paths in the first set of pockets along the length of said pockets; and treating fluid inlet and outlet means in the housing adjacent opposed ends of said stack in communication with the second set of pockets, thereby establishing overall treating fluid flow paths in the second set of pockets along the length of said pockets. 2. A device of claim 1 wherein said first and second strands in said blood pocket support screens are both of circular cross-section with substantially the same diameter, and said first and second strands in said treating fluid pocket support screens are both of circular cross-section with substantially the same diameter. 3. A device of claim 2 wherein the strand diameter in the blood pocket support screens is substantially the same as the strand diameter in the treating fluid pocket support screens. 4. A device of claim 1 wherein said first and second strands in said blood pocket support screens are both oriented at substantially the same acute angle with respect to said fold lines, and said first and second strands in said treating fluid pocket support screens are both oriented at substantially the same acute angle with respect to said fold lines. 5. A device of claim 4 wherein said first and second strands in said blood pocket support screens are oriented at a larger acute angle with respect to said fold lines than are said first and second strands in said treating fluid pocket support screens. 6. A device of claim 5 wherein said first strands in said blood pocket support screens are oriented with respect to said second strands in said blood pocket support screens at an angle of about 60°, said first strands in said treating fluid pocket support screens are oriented with respect to said second strands in said treating fluid pocket support screens at an angle of about 60°, said first and second strands in said blood pocket support screens are oriented at an angle of about 60° with respect to the fold lines of said membrane, and said first and second strands in said treating fluid pocket support screens are oriented at an angle of about 30° with respect to said fold lines. 7. A device of claim 1 wherein said blood pocket support screens and said treating fluid pocket support screens are both cut from the same non-woven stock material, with the direction of cut in said stock material of the longitudinal edges of said blood pocket support screens being substantially perpendicular to the direction of cut in said stock material of the longitudinal edges of said treating fluid pocket support screens. 8. A device of claim 1 wherein, at least in the vicinity of said blood inlet and outlet means, said blood pocket support screens are slightly wider than said membrane folds. 9. A device of claim 1 wherein said support screens have substantially the same length as said folds, said housing includes two opposed side walls substantially parallel to said folds, and said device includes additionally first and second substantially identical shims, said first shim being in compression between one of said side walls and the top of said compacted stack and said second shim being in compression between the other of said side walls and the bottom of said stack, with each of said shims being centrally disposed between the ends of said stack, having at least about the same width as said stack, having a length of from about 10% to about 50% of that of said stack, and having a thickness of from about 1% to about 10% of the height of said compacted stack at the ends of said stack, whereby said shims serve to substantially improve the mass transfer performance of the device without excessively increasing the blood pressure drop across the device. 10. A device of claim 9 wherein each of said shims has a length of from about 20% to about 40% of the length of said stack. 11. A device of claim 10 wherein each of said shims has a thickness of about 2% of the height of said compacted stack and a length of about one-third of the length of said stack. 12. A mass transfer device for the treatment of blood comprising: a housing having first and second opposed walls; a pleated, selectively permeable membrane disposed within the housing as a compressed stack of substantially rectangular folds defining first and second sets of alternating pockets for the flow of blood and a treating fluid, with the fold lines of said membrane being adjacent to said first and second walls; a plurality of discrete support screens each disposed within one of said pockets of said first and second sets, said screens having substantially the same length and width as said folds; blood inlet and oulet means in said first wall of the housing adjacent opposed ends of said stack in communication with the first set of pockets, thereby establishing overall blood flow paths in the first set of pockets along the length of said pockets; and treating fluid inlet and outlet means in said second wall of the housing adjacent opposed ends of said stack in communication with the second set of pockets, thereby establishing overall treating fluid flow paths in the second set of pockets along the length of said pockets, with said screens being provided with a pair of transversely-extending cut-out regions adjacent their opposed ends to improve fluid distribution across said pockets, the cut-out regions in the screens disposed in said first set of pockets being tapered with decreasing width away from the blood inlet and blood outlet means and being positioned in a non-overlapping manner with respect to the cut-out regions in the screens disposed in said second set of pockets.