# US 5,348,691 A · Atmosphere membrane humidifier and method and system for producing humidified air > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,348,691 A - Document ID: US5348691A - Status: Granted - Kind: A - Application number: 08/076,459 - Filed: 1993-06-11 - Granted: 1994-09-20 - Earliest claimed: 1993-06-11 - Assignees: United Technologies Corporation - Inventors: James F. McElroy; William F. Smith; Joseph E. Genovese - Web page: https://patentgrep.com/patent/US5348691A ## CPC - F24F 3/14: by humidification; by dehumidification - F24F 6/00: Air-humidification {, e.g. cooling by humidification} - F24F 2003/1435: {comprising semi-permeable membrane} - Y02A 20/00: Water conservation; Efficient water supply; Efficient water use - Y10S 261/46: Residue prevention in humidifiers and air conditioners - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A membrane humidifying device is disclosed that can operate with normal potable quality water without a demineralizer and which prevents the transport of microbes, particulates, dissolved salts and liquid water to the airstream. It is positioned in the flow path of air to be humidified and comprises at least one membrane cell and a means for introducing water into each cell. The membrane cell is comprised of at least one sheet of a hydrophilic membrane and at least one screen. Ambient or low pressure water is introduced into the membrane cell(s); at least a portion of which contacts or passes through the screen(s); contacts the hydrophilic membrane(s); and is osmotically transported across the membrane(s) where it evaporates into the airstream. ## Claims ### Claim 1 A membrane humidifying device that comprises at least one membrane cell and a means for introducing water into said cell wherein said membrane cell comprises: a. at least one sheet of a hydrophilic membrane, having a first side and a second side, capable of osmotically transporting water from said first side to said second side; and b. at least one screen for providing structural integrity to said hydrophilic membrane(s), wherein each screen is located adjacent to said first side of at least one membrane and wherein said screen(s) has a mesh side of about 2/0 to about 6/0 and a thickness of about 0.05 to about 0.5 millimeters; wherein said means for introducing water into said cell directs water to said first side(s) of said hydrophilic membrane(s). ### Claim 2 (depends on 1) The membrane humidifying device of claim 1 wherein said membrane cell comprises the following four contiguous layers: a. a first sheet of a hydrophilic membrane; b. a first screen; c. a second screen; and d. a second sheet of a hydrophilic membrane, wherein said first membrane sheet and said second membrane sheet form a channel which loosely contains said first screen and said second screen. ### Claim 3 (depends on 1, 2) The membrane humidifying device of claims 1 or 2 wherein said hydrophilic membrane is an ion exchange membrane selected from the group consisting of perfluorocarbon sulfonic acid membranes and polystyrene sulfonic acid membranes. ### Claim 4 (depends on 3) The membrane humidifying device of claim 3 wherein said hydrophilic membrane is perfluoro-sulfonic acid membrane. ### Claim 5 (depends on 1, 2) The membrane humidifying device of claims 1 or 2 wherein said screens are metal screens wherein said metal is selected from the group consisting of silver, aluminum, stainless steel and mixtures thereof. ### Claim 6 A system for producing humidified air which comprises: a. a membrane humidifying device that comprises at least one membrane cell and a means for introducing water into said cell wherein said membrane cell comprises: i. at least one sheet of a hydrophilic membrane having a first side and a second side: capable of osmotically transporting water from said first side to said second side: and ii. at least one screen for providing structural integrity to said hydrophilic membrane(s), wherein each screen is located adjacent to said first side of at least one membrane and wherein said screen(s) has a mesh size of about 2/0 to about 6/0 and a thickness of about 0.05 to about 0.5 millimeters; wherein said means for introducing water into said cell directs water to said first side(s) of said hydrophilic membrane (s); b. a liquid reservoir for the temporary storage of water in fluid connection with said membrane humidifying device; c. a means for the introduction of water into said liquid reservoir; and d. a means for regulating the pressure of water flowing from said membrane humidifying device to said liquid reservoir. ### Claim 7 (depends on 6) The system for producing humidified air of claims 6 wherein said screens are metal screens wherein said metal is selected from the group consisting of silver, aluminum, stainless steel and mixtures thereof. ### Claim 8 (depends on 6) The system for producing humidified air of claim 6 wherein said membrane cell comprises the following four contiguous layers: a. a first sheet of a hydrophilic membrane; b. a first screen; c. a second screen; and d. a second sheet of a hydrophilic membrane, wherein said first membrane sheet and said second membrane sheet form a channel which loosely contains said first screen and said second screen. ### Claim 9 (depends on 6) The system for producing humidified air of claim 6 wherein said liquid reservoir comprises: a. a means to constantly monitor the water level in said liquid reservoir wherein said means is in electronic contact with a fill valve that is in fluid contact with said liquid reservoir; and b. a means to constantly monitor the conductivity level of water in said liquid reservoir wherein said means is in electronic contact with a purge valve that is in fluid contact with said liquid reservoir. ### Claim 10 (depends on 6) The system for producing humidified air of claim 6 wherein said means for regulating the pressure of water flowing from said membrane humidifying device to said liquid reservoir is a positive displacement pump. ### Claim 11 (depends on 6, 8) The system for producing humidified air of claims 6 or 8 wherein said hydrophilic membrane is an ion exchange membrane selected from the group consisting of perfluorocarbon sulfonic acid membranes and polystyrene sulfonic acid membranes. ### Claim 12 (depends on 11) The system for producing humidified air of claim 11 wherein said hydrophilic membrane is perfluoro-sulfonic acid membrane. ### Claim 13 A method for producing humidified air using a membrane humidifying device which comprises at least one membrane cell and a means for introducing water into said cell and which is positioned in the flow path of air to be humidified, said method comprising: a. introducing ambient or low pressure water into said membrane cell(s) which comprises at least one sheet of a hydrophilic membrane, having a first side and a second side, and at least one screen for providing structural integrity to said membrane(s) wherein said screen(s) has a mesh size of about 2/0 to about 6/0 and a thickness of about 0.05 to about 0.5 millimeters; b. contacting said water with said screen(s); c. contacting said water with said first side(s) of said hydrophilic membrane(s); d. osmotically transporting said water across said membrane(s) to said second side(s) of said membrane(s); and e. evaporating said transported water into said flow path of air. ### Claim 14 A method for producing humidified air using a system for producing humidified air which comprises a membrane humidifying device having at least one membrane cell and a means for introducing water into said cell; a liquid reservoir in fluid connection with said membrane humidifying device; a means for the introduction of water into said liquid reservoir; and a means for regulating the pressure of water flowing from said membrane humidifying device to said liquid reservoir; and which is positioned in the flow path of air to be humidified, said method comprising: a. introducing water into said liquid reservoir; b. introducing ambient or low pressure water from said liquid reservoir to said membrane cell(s) which comprises at least one sheet of a hydrophilic membrane, having a first side and a second side, and at least one screen for providing structural integrity to said membrane ( s ) wherein said screen(s) has a mesh size of about 2/0 to about 6/0 and a thickness of about 0.05 to about 0.5 millimeters; c. contacting said water with said screens; d. contacting said water with said first side(s) of said hydrophilic membrane(s); e. osmotically transporting said water across said membrane(s) to said second side(s) of said membrane(s); evaporating said transported water into said flow path of air; and g. flowing water not transported across said membrane(s) to said pressure regulating means and then to said liquid reservoir. ### Claim 15 (depends on 14) The method for producing humidified air of claim 14 wherein water not transported across said membrane(s) is recycled through said system.