# US 11,305,237 B2 · Spiral membrane element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,237 B2 - Document ID: US11305237B2 - Status: Granted - Kind: B2 - Application number: 16/333,402 - Filed: 2017-09-15 - Published: 2019-08-22 - Granted: 2022-04-19 - Earliest claimed: 2016-09-16 - Assignees: Nitto Denko Corporation - Applicants: Nitto Denko Corporation - Inventors: Mieko Nishi; Yasuhiro Uda - Web page: https://patentgrep.com/patent/US11305237B2 ## CPC - B01D 63/10: Spiral-wound membrane modules - B01D 63/00: Apparatus in general for separation processes using semi-permeable membranes - B01D 69/10: Supported membranes; Membrane supports - B01D 69/12: Composite membranes; Ultra-thin membranes - C08J 5/22: Films, membranes or diaphragms - D04B 21/00: Warp knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes - D04B 21/06: Patterned fabrics or articles (open-work fabrics D04B21/10) - B01D 2313/04: Specific sealing means - B01D 2313/143: on the feed side - B01D 2313/146: on the permeate side - B01D 2325/02: Details relating to pores or porosity of the membranes - B01D 2325/04: Characteristic thickness - B01D 2325/06: Surface irregularities - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - D04B: KNITTING ## Abstract 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, and the thickness of the supply-side flow-channel member is from 10 to 110 mil. ## Claims ### Claim 1 A spiral membrane element, comprising a plurality of 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 from being mixed with a permeation-side flow-channel; wherein the spiral membrane element has an efficiency index E of 0.024 to 0.10, the index E being calculated in accordance with the following expression: efficiency index: E=0.0024×X−0.2373+(Y/(D2×L)) wherein X is a thickness [mil] of the supply-side flow-channel member, Y is an effective membrane area [ft2] 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 L being defined with reference to a length of the perforated central pipe; the separation membranes independently have thicknesses from 80 to 100 μm; and the thickness of the supply-side flow-channel member is from 26 to 110 mil. ### Claim 2 (depends on 1) The spiral membrane element according to claim 1, wherein the separation membranes are each a composite semipermeable membrane having a porous support, and a separating functional layer on a surface of the porous support. ### Claim 3 (depends on 2) The spiral membrane element according to claim 2, wherein in the composite semipermeable membrane, the separating functional layer is located on/over an outer surface of each of the membrane leaves, and the porous support has a nonwoven fabric layer having a density of 0.85 to 1.0 g/cm3 and a polymer porous layer on/over one surface of the nonwoven fabric layer. ### Claim 4 (depends on 2) The spiral membrane element according to claim 2, wherein the permeation-side flow-channel member is a tricot knit having a density of 0.4 to 0.8 g/cm3. ### Claim 5 (depends on 4) The spiral membrane element according to claim 4, wherein the permeation-side flow-channel member comprises a tricot knit having a plurality of ribs each made to comprise loops repeated linearly in a longitudinal direction, and a plurality of grooves present between these ribs, and the permeation-side flow-channel member has a membrane support index of 60 or more, the index being calculated in accordance with the following expression: number (wale) of the grooves per 25-mm×{rib width (mm)/groove width (mm)}. ### Claim 6 (depends on 3) The spiral membrane element according to claim 3, wherein the permeation-side flow-channel member is a tricot knit having a density of 0.4 to 0.8 g/cm3. ### Claim 7 (depends on 6) The spiral membrane element according to claim 6, wherein the permeation-side flow-channel member comprises a tricot knit having a plurality of ribs each made to comprise loops repeated linearly in a longitudinal direction, and a plurality of grooves present between these ribs, and the permeation-side flow-channel member has a membrane support index of 60 or more, the index being calculated in accordance with the following expression: number (wale) of the grooves per 25-mm×{rib width (mm)/groove width (mm)}.