Spiral mass transfer device with low flow resistance and fluid volume

Claim 2

A mass transfer device which comprises a foraminous screen member supporting and lying against a length of semipermeable membrane of flattened tubular shape, said screen member and membrane being arranged in a spiral about a core, said screen member comprising first and second sets of spaced parallel strands in separate planes, said sets of strands lying against each other and defining an angle thereto, and connected to each other at their crossing points, the first set of strands being disposed in longitudinal relation to the axis of the tubular membrane, the strands of said first set having center lines spaced apart from each other by a distance which is two to about three times the corresponding spacing distance between the strands of said second set.

Claim 3

The mass transfer device of claim 1 in which said strands are generally triangular in cross section, and in which said triangular strand elements are, in cross section, 0.01 to 0.04 inch in height from apex to base, and said base is 0.01 to 0.04 inch in width, and said angle between the first and second strand elements is 40* to 60* .

Claim 4

The mass transfer device of claim 2 in which said first strands have centerlines spaced 0.12 to 0.14 inch apart and the second strands are spaced 0.06 to 0.07 inch apart.

Claim 5

The mass transfer device of claim 3 which is an artificial kidney having a blood flow path through said tubular membrane.

Claim 6

The mass transfer device of claim 4 in which said first strand elements are parallel to the axis of said tubular membrane.

Claim 7

A mass transfer device which comprises a foraminous screen member supporting and lying against a length of semipermeable membrane of flattened tubular shape, said screen member and membrane being arranged in a spiral about a core, said screen member comprising a first set of spaced parallel strands and a second set of spaced parallel strands in a separate plane lying against said first set of strands and defining an angle thereto, said first and second sets of strands being connected to each other at their crossing points, said first set of strands being disposed in longitudinal relation to the axis of said tubular membrane and spaced apart from each other from 0.1 to 0.14 inch, to provide a low pressure drop of fluid flowing through said tubular membrane, the second set of strands being spaced apart from each other by 0.05 to 0.09 inch, to provide a low fluid volume within said tubular membrane.

Claim 8

A mass transfer device which comprises a foraminous screen member supporting and lying against a length of semipermeable membrane of flattened tubular shape, said screen member and membrane being arranged in a spiral about a core, said screen member comprising a first set of spaced parallel strands and a second set of spaced parallel strands in a separate plane lying against said first set of strands and defining an angle thereto, said first and second sets of strands being connected to each other at their crossing points, said first set of strands being disposed in longitudinal relation to the axis of said tubular membrane and spaced apart from each other from 0.1 to 0.14 inch, to provide a low pressure drop of fluid flowing through said tubular membrane, the second set of strands being spaced apart from each other by 0.05 to 0.09 inch, to provide a low fluid volume within said tubular membrane.

Claim 9

The mass transfer device of claim 6 in which the spacing of said first strands is from 0.11 to 0.13 inch and the spacing of said second strands is about 0.08 inch, said first and second strands having a triangular cross section with outwardly directed apexes, said cross section having a base of about 0.03 inch and an elevation of 0.02 to 0.03 inch.

Claim 10

The mass transfer device of claim 7 which is an artificial kidney having a blood flow path through said tubular membrane.

Claim 11

A mass transfer device which comprises a foraminous screen member supporting and lying against a lenGth of semipermeable membrane of flattened tubular shape, said screen member and membrane being arranged in a spiral about a core, said screen member comprising a first set of spaced parallel strands and a second set of spaced parallel strands in a separate plane lying against said first strands and defining an angle thereto, said first and second strands being connected to each other at their crossing points, each strand providing a pointed ridge, the point of which is directed outwardly in a direction substantially normal to the plane of said screen member, the ridges of said strands providing support for said dialyzing tubing and defining a plurality of fluid flow channels between said strands, the first strands being disposed in longitudinal relation to the axis of said tubular membrane and having centerlines spaced apart from 0.10 to 0.14 inch to provide a low pressure drop for fluid flowing through said tubular membrane, the second strands having centerlines spaced apart from each other by 0.05 to 0.09 inch to provide a low fluid volume within said tubular membrane.

Claim 12

A mass transfer device which comprises a foraminous screen member supporting and lying against a lenGth of semipermeable membrane of flattened tubular shape, said screen member and membrane being arranged in a spiral about a core, said screen member comprising a first set of spaced parallel strands and a second set of spaced parallel strands in a separate plane lying against said first strands and defining an angle thereto, said first and second strands being connected to each other at their crossing points, each strand providing a pointed ridge, the point of which is directed outwardly in a direction substantially normal to the plane of said screen member, the ridges of said strands providing support for said dialyzing tubing and defining a plurality of fluid flow channels between said strands, the first strands being disposed in longitudinal relation to the axis of said tubular membrane and having centerlines spaced apart from 0.10 to 0.14 inch to provide a low pressure drop for fluid flowing through said tubular membrane, the second strands having centerlines spaced apart from each other by 0.05 to 0.09 inch to provide a low fluid volume within said tubular membrane.

Claim 13

The mass transfer device of claim 6 in which the spacing of said first strands is from 0.11 to 0.13 inch, and the spacing of said second strands is about 0.08 inch.

Claim 14

The mass transfer device of claim 6 in which said first and second sets of strands define an angle to each other of about 40* to 60*.

Claim 15

The mass transfer device of claim 6 in which said strands are triangular in cross section of approximately equilateral shape, having a base of 0.01 to 0.04 inch and an altitude of 0.01 to 0.04 inch.