An osmosis element comprising a central permeate tube and a membrane element, the membrane having a first part and a second part, the first part having a top edge for location adjacent the central tube, the second part being disposed at the opposite edge, the first part comprising a material to allow water to flow therethrough, the second part comprising at least two adjacent permeate spacers extending from the first part to allow water to flow therethrough, the permeate spacers having a semi-permeable membrane attached to opposed faces of the two adjacent permeate spacers, the first part comprising a barrier extending from the vicinity of the top edge, the central tube comprising an external wall and a longitudinally extending internal separator defining a first channel and a second channel each extending longitudinally of the central permeate tube, at least one first aperture extending from the first channel though the external wall and at least one second aperture extending from the second channel through the external wall.

Provided is a spiral membrane element that has a restricted outer diameter and is capable of being decreased in operation energy therefor. The element is a spiral membrane element including plural membrane leaves in each of which a permeation-side flow-channel member is interposed between opposed separation membranes; a supply-side flow-channel member interposed between any two of the membrane leaves; a perforated central pipe on which the membrane leaves and the supply-side flow-channel member are wound; and a sealing part that prevents a supply-side flow-channel member from being mixed with a permeation-side flow-channel member. This element has an efficiency index E of 0.005 to 0.10, the index being calculated in accordance with an expression described below, and the thickness of the supply-side flow-channel member is from 10 to 110 mil. Efficiency index: E=0.0024X0.2373+(Y/(D.sup.2L)) wherein X is a thickness [mil] of the supply-side flow-channel member, Y is an effective membrane area [ft.sup.2] of the separation membranes, D is an outer diameter [inch] of the membrane element, and L is a length [inch] of the membrane element.

The present invention provides compact spiral-wound filter elements having cassette-like performance. The invention further provides filtration systems (e.g., TFF systems) and processes (e.g., SPTFF processes) employing compact spiral-wound filter elements having cassette-like performance.

A component for a spiral wound membrane, suitably for water filtration. The component includes an integrally formed non-uniform lattice structure. The lattice structure includes a first and second repeating unit cell, wherein the first and second unit cell are different.

The present invention provides a spiral membrane element suitable for suppressing a decrease in a permeation rate (or a permeation flux) of a permeated fluid from a separation membrane. A spiral membrane element of the present invention includes: a central tube; a membrane leaf that has a separation membrane and a permeation spacer and is wound around the central tube; and a flow passage spacer that is connected to the permeation spacer and is wound around the central tube on a side closer to the central tube than the membrane leaf is. A pressure loss of the flow passage spacer measured by a predetermined test is smaller than a pressure loss of the permeation spacer.

Filter elements for perfusion systems and methods are provided. A filter element sheet includes a microporous membrane having a mean pore size of at least about 0.65 ?m and a feed spacer comprising woven fibers and having an open area of at least about 35%. The filter element sheet can be arranged within a filter element, for example, in a spiral-wound format or in a cassette format. A perfusion system includes at least one filter element and a pump configured to control flow of a liquid feed through the at least one filter element.

A spiral membrane element is provided which has a restricted outer diameter but is heightened in effective membrane area, and further which can be decreased in operation energy therefor. The spiral membrane element is an element including plural membrane leaves L in each of which a permeation-side flow-channel member 3 is interposed between opposed separation membranes 1; a supply-side flow-channel member 2 interposed between any two of the membrane leaves L; a perforated central pipe 5 on which the membrane leaves L and the supply-side flow-channel member 2 are wound; and sealing parts that prevent a supply-side flow-channel from being mixed with a permeation-side flow-channel. The sealing parts include both-end sealing parts 11 in which an adhesive is used to seal two-side end parts of each of the membrane leaves L on both sides of the leaf in an axial direction A1 of the leaf. The thickness T1 of the both-end sealing parts 11 is 390 to 540 m.

A method for producing a spiral wound separation membrane element includes preparing a composite semipermeable membrane having a skin layer on the surface of a porous support. The method further includes forming on the skin layer a protective layer containing 35 mg/m.sup.2 or more of an anionic polyvinyl alcohol to prepare a protective layer-equipped composite semipermeable membrane, preparing an unwashed spiral wound separation membrane element from the protective layer-equipped composite semipermeable membrane, and passing wash water through the unwashed spiral wound separation membrane element to remove the protective layer on the skin layer.

A spiral wound membrane module adapted for hyperfiltration and including at least one membrane envelope and feed spacer sheet wound about a central permeate tube to form an inlet and outlet scroll face and an outer periphery, wherein the feed spacer sheet includes: i) a feed entrance section extending along the permeate collection tube from the inlet scroll face toward the outlet scroll face, ii) a feed exit section extending along the outer periphery from the outlet scroll face toward the inlet scroll face, and iii) a central feed section located between the feed entrance section and the feed exit section; and wherein the feed entrance section has a median resistance to flow in a direction parallel to the permeate collection tube that is less than 25% of the median resistance to flow of the central feed section in a direction perpendicular to the permeate collection tube.

A spiral wound membrane element and a method for cleaning a spiral wound membrane sheet are provided. The spiral wound membrane element comprising a perforated central tube; one or more membrane sleeves, each sleeve comprising two membrane sheets enclosed at two edges around a feed spacer sheet and wrapped around the central tube; a permeate carrier sheet attached to the central tube at a first edge opposite a second edge; and a seal on third and fourth edges of the permeate carrier sheet. The method comprises introducing two solution with different solute concentration to two sides of the spiral wound membrane sheet; establishing a concentration gradient between the first and second sides; communicating a first solvent from the first side to the second side to remove a foulant located on the second side of the membrane sheet; and collecting a waste stream that contains the foulant.