Abstract: A membrane separation process for the enrichment of at least one gas component in a gas flow, especially for the oxygen enrichment of the air and/or for the enrichment of carbon dioxide using a membrane separation device (10), which is a part of a membrane separation unit (2) and includes at least one membrane. The gas is separated into a retentate (8), which is discharged on the retentate side (12) of the membrane, and a permeate (9), which is discharged on the permeate side (11) of the membrane. To allow the separation of gases or the enrichment of a gas component in a gas flow at a low energy consumption rate and at low investment and production costs, the pressure of the gas stream is lowered before entering the membrane separation unit (2) so that pressure on the permeate side (11) is lower as compared with the inlet pressure.

Abstract: A filter membrane, methods of making such filter membrane and apparatus employing such filter membrane are disclosed, in which the filter membrane is a monolithic polymeric membrane that includes a polymeric filter layer including a micron-scale precision-shaped pores and a polymeric support layer that has a precision-shaped porous support structure for the filter layer. Several methods are disclosed for making such a membrane using micromachining techniques, including lithographic, laser ablation and x-ray treatment techniques. Several filter apparatus employing such a membrane are also disclosed.

Abstract: A fuel stabilization system includes a first deoxygenator and a second deoxygenator both for removing dissolved oxygen from a hydrocarbon fuel. The first and second deoxygenators are arranged in parallel or series to sequentially remove a portion of dissolved oxygen from the hydrocarbon fuel. The arrangement of several deoxygenators for a single fuel stream improves removal of dissolved oxygen and provides for scalability of the fuel system to meet application specific demands. The arrangement also provides for the preservation of partial system functionality in the event of the failure of one of the deoxygenator modules.

Abstract: An artificial lung includes a housing, a tubular hollow fiber membrane bundle contained in the housing and providing a multiplicity of hollow fiber membranes having a gas exchange function, a gas inflow port and a gas outflow port communicating with each other through hollow portions of the hollow fiber membranes, and a blood inflow port and a blood outflow port through which blood is distributed. The tubular hollow fiber membrane bundle has a cylindrical overall shape, and a filter member having a bubble-trapping function is provided on an outer peripheral portion of the tubular hollow fiber membrane bundle.

Abstract: An apparatus for removing gas bubbles from a fluid includes a fluid inlet and a separation chamber that is in fluid communication with the fluid inlet. The separation chamber has first and second end portions, with the first end portion being operably oriented gravitationally above the second end portion. The apparatus further includes a first gas-permeable, liquid-impermeable membrane disposed in the separation chamber and extending substantially along a first axis defined as extending between the first and second end portions. A permeate side of the membrane is exposed to an environment having a second partial pressure of a target gas, which second partial pressure is lower than a first partial pressure of the gas in the fluid.

Abstract: This abstract discusses membranes needed to separate fluids for the production of oxygen-enriched air, nitrogen-enriched-air, for the separation of carbon dioxide from hydrocarbons, and the separation of hydrogen from various petrochemical and oil refining streams. Membranes are needed that provide a resistance to interaction with process components or contaminants, provide the mechanical strength required to withstand high membrane differential pressures and high process temperatures, and exhibit sufficient maximum strain such that membranes are not brittle and can easily be formed into desirable membrane forms. Membranes of polyimide polymers, particularly polyimide polymers sold under the trade name P-84, are annealed in a controlled annealing step to improve the mechanical properties of the polymers used to make separation membranes.

Abstract: The invention relates to a hollow fiber separation module comprising an inlet (20) for the gas to be dried, an outlet (22) for dried gas, an access element (26) and a discharge element (28) for circulation gas, and a plurality of hollow fibers which respectively extend from the inlet (29) to the outlet (22) and comprise an inner region which communicates with the inlet (20) on one end of each hollow fiber, and with the outlet (22) on the other end of each hollow fiber. The hollow fibers are wound up in a plurality of layers (40, 42, 44) to form a hollow cylindrical winding. Each layer (40, 42, 44) is inwardly defined by an imaginary cylinder (35, 36, 37) and has a number of hollow fibers which are wound onto the cylinder (35, 36, 37) in a helical manner with an alpha angle of inclination, are located at a distance a from each other, and are arranged on the cylinder in a homogeneously distributed manner. A layer (40) differs from an adjacent layer (e.g.

Abstract: A gas-separation membrane module assembly and a gas-separation process using the assembly. The assembly includes a set of tubes, each containing gas-separation membranes, arranged within a housing. The housing contains tube sheets that divide the space within the housing into three separate, gas-tight spaces, with the tubes mounted in the central space. Within this space, each tube has an aperture or hole in its wall that enables gas that has been retained on the feed side of the membranes to flow out of the tubes and into the space. The assembly can be used in various ways to carry out gas separation processes.

Abstract: There is disclosed a method of making a high performance carbon membranes from polymer membranes. The method comprising the steps of exposing polymer precursor compounds to a polar organic liquid before pyrolysis of the exposed polymer precursor compounds.

Abstract: An apparatus and process are presented that provide for the separation of hydrogen peroxide from a solution having an acid and hydrogen peroxide.

Abstract: A hydrogen purification system that is used to separate hydrogen gas from a source gas. The hydrogen purification system has a hydrogen separator into which the source gas is permitted to flow. Within the hydrogen separator is at least one hydrogen permeable tube that is made of a hydrogen permeable material. A support tube is provided for each hydrogen permeable tube. A support tube is coaxially aligned with the hydrogen permeable tube, wherein a gap space exists between the hydrogen permeable tube and the support tube in an area of overlap. The source gas is introduced into the gap space. The source gas spreads thinly over the hydrogen permeable tube in the gap space. Hydrogen from the source gas passes through the hydrogen permeable tube in a highly efficient manner and is collected.

Abstract: A device and method for preventing ingression of contaminants and moisture and for removing moisture from a fluid reservoir, the device comprising a fluid reservoir for supporting a fluid therein, a fluid reservoir opening for allowing an exchanging of air between an interior of the fluid reservoir and the ambient surrounding, and a membrane-based reservoir dryer located in fluid communication with the fluid reservoir, the membrane-based reservoir dryer comprising a source of compressed gas and a membrane dryer for drying the compressed gas to increase the capacity of the compressed gas for absorbing moisture from the fluid in the reservoir.

Abstract: Air is introduced from an intake chamber into a plurality of hollow fiber membranes in a casing. The casing is connected to a vacuum pump via a three-way valve and water vapor in air is evacuated through the membranes. Dehumidified or dried air is discharged from a discharge chamber at the ends of the membranes. The vacuum pump is connected to a detector/selector. If the vacuum pump is out of order, it is detected by the detector/selector and another dehumidifier including a depressurizing device is actuated.

Abstract: In a hollow fiber membrane flat module according to the present invention, both ends of hollow fiber membrane bundle which are formed by bundling a plurality of hollow fiber membrane as a sheet are fixed to two housing separately by a fixing resin while maintaining an opening condition in an opening end section in the follow fiber membrane. Furthermore, a maximum width in an orthogonal direction to a longitudinal direction of the hollow fiber membrane is no longer than 25 mm in a cross section which is orthogonal to a longitudinal direction of the housings, and a maximum deflection in the housings which are measured according to a method for measuring the deflection according to the present invention is not more than 1% of a distance between the two housings.

Abstract: An inerting system and method characterized by a primary air separation module configured to communicate with an upstream source of pressurized air at elevated temperature for production of a primary downstream flow of nitrogen-enriched air to be delivered to a space to be inerted; a secondary air separation module configured to communicate with the upstream source of pressurized air at elevated temperature for production of a supplemental downstream flow of nitrogen-enriched air to be delivered to a space to be inerted when high nitrogen-enriched airflow is desired during a high flow period; and a flow controller configured to provide a warming flow through the secondary air separation module to heat the secondary air separation module to above ambient temperature during a warming period other than the high flow period.

Abstract: The present invention is directed to an apparatus and a method for continuously removing water vapor from a closed loop, re-circulated gas flow in an ion mobility spectrometer using a water permeable membrane, having a first side and a second side opposite the first side. The gas flow is disposed adjacent and carried past the first side to deposit water vapor that passes through the membrane to the second side. An exhaust flow is disposed adjacent and carried passed the second side of the membrane to remove the water vapor from the system. Therefore, the water removal apparatus continuously regenerates in-situ. Heaters, heat sinks and additional treatment systems including charcoal filters can also be included in the system to enhance its performance.

Abstract: A moisture exchange module has a bundle of moisture-permeable hollow fiber membranes and at least one line element for supplying a gas stream that flows through the hollow fibers in an inner flow. The at least one line element opens out into an inflow region, which is of at least approximately the same cross section as the bundle of hollow fiber membranes. According to the present invention, the at least one line element opens out into the inflow region at an angle of from 60° to 120° with respect to the longitudinal axis of the bundle of hollow fiber membranes without the longitudinal axes of the one line element and of the bundle of hollow fiber membranes intersecting one another. An annular diverter means for diverting the gas flow are provided between the cross section of the line elements through which gas can flow and the inflow region.

Abstract: The present invention provides for a process for producing carbon monoxide. A feed gas stream of hydrogen, carbon monoxide and carbon dioxide is directed to a membrane unit which separates the feed gas stream into two streams. The stream containing carbon monoxide is directed to second membrane unit for further purification and the steam containing the carbon dioxide and hydrogen is fed to a reverse shift reactor to produce more carbon monoxide. The carbon monoxide recovered from the reverse shift reactor is purified in a third membrane unit and directed back to the first membrane unit and is further purified and recovered as additional carbon monoxide product.

Abstract: A helically wound hollow membrane module having a core with a plurality of helically wound layers of semi-permeable hollow fibers wound on the core. The fiber wind angle with respect to any one layer of fibers may be essentially constant along the axial length of the module, except in one or both end or tubesheet regions, where the wind angle may be increased, in at least some of the layers relative to the essentially constant wind angle, to produce an area of decreasing diameter.

Abstract: A membrane air dryer includes a proportioning valve for providing sweep air to the dryer. The valve may be located in an easily accessible location and may be oriented so that the movable valve element extends transverse to the length of the shell. The valve may be configured to allow air to flow back from the delivery port to the fibers during a compressor unload cycle to maintain pressure on the fibers, while blocking flow of air from the delivery port to the sweep chamber.

Abstract: The invention relates to a filter module having a module housing and at least one filter element. The filter module has at least one inlet opening, at least one filtrate outlet and a module housing having at least one joint line.

Abstract: A gas-separation membrane assembly, and a gas-separation process using the assembly. The assembly incorporates multiple gas-separation membranes in an array within a single vessel or housing, and is equipped with two permeate ports, enabling permeate gas to be withdrawn from both ends of the membrane module permeate pipes.

Abstract: A system and method for separation of a gas, e.g., carbon dioxide, from a gaseous mixture using a hollow fiber membrane module. The module contains an absorbent solution that is effective in absorbing the gas for an extended period, e.g., eight hours, without regeneration or replacement. The absorbent solution is then regenerated by passing a sweep gas through the hollow fibers in the module. The separation system is particularly useful for fuel cell and battery applications.

Abstract: A method and apparatus for separating a component from a multi-component feed gas stream has a flow conduit (14) having a semi-permeable section (15) that permeates the component to be separated from feed gas stream (12). A sweep gas is provided at a first velocity on the permeate sides of flow conduit (14) and the velocity of sweep gas (13) is accelerated so that the velocity of sweep gas (13) along at least a portion of the permeate side of flow conduit (14) is greater than the first velocity. The mixture of permeate and sweep gas (13) is then decelerated by diffuser (20), thereby recovering as pressure a portion of the energy of feed gas stream (12).

Abstract: There is provided a high efficient gas separation membrane of two or more layers, which comprises a separating layer of 3-dimensional nanostructure and a supporting layer, wherein the 3-dimensional nanostructure can maximize a surface area per unit permeation area.

Abstract: A mixed matrix membrane for separating gas components from a mixture of gas components is disclosed. The membrane comprises a continuous phase polymer with inorganic porous particles, preferably molecular sieves, interspersed in the polymer. The polymer has a CO2/CH4 selectivity of at least 20 and the porous particles have a mesoporosity of at least 0.1 cc STP/g. The mixed matrix membrane exhibits an increase in permeability of least 30% with any decrease in selectivity being no more than 10% relative to a membrane made of the neat polymer. The porous particles may include, but are not limited to, molecular sieves such as CVX-7 and SSZ-13, and/or other molecular sieves having the required mesoporosity. A method for making the mixed matrix membrane is also described. Further, a method is disclosed for separating gas components from a mixture of gas components using the mixed matrix membrane with mesoporous particles.

Abstract: A process for the manufacture of a polyimide hollow fibre comprising: (i) providing a dope solution comprising one or more polyimides dissolved in a solvent comprising 60-100 wt % N-methylpyrollidone and 0-40 wt % ethanol, (ii) providing a bore fluid, (iii) generating a tube of the dope solution filled with the bore fluid, (iv) bringing the product of step (iii) into contact with a coagulation solvent to form a hollow fiber.

Abstract: An apparatus and method to separate a mixture of gases—such as carbon dioxide and methane—by an inorganic membrane comprising a ceramic support and a silica layer made from a silicon elastomer sol. The apparatus and method can efficiently separate the gaseous mixture and can also cope with the extreme conditions found in e.g. hydrocarbon producing wells. A method of manufacturing the apparatus is also disclosed.

Abstract: A mass transfer or energy transfer module is provided which includes a manifold, a cartridge and a bowl which houses the cartridge. The cartridge and bowl are connected to each other at least two flanges which fit into slots of the bowl to form a unitary construction.

Abstract: An air dehydration membrane is made of a hydrophilic polymer having a permeability for water vapor which is greater than its permeability for air, and having low selectivity between oxygen and nitrogen. The membrane has a hydrophilic coating, which itself may be a polymer. The coating does not affect the selectivity of the coated membrane with respect to oxygen and nitrogen, but does increase selectivity of the membrane with respect to water vapor. A preferred material for the membrane is polysulfone. Preferred materials for the coating are poly vinyl alcohol and Triton X-100. The membrane is selected such that the dominant mechanism for gas flow through the membrane is Knudsen flow. The membranes are made at low cost, and can outperform existing commercial membranes in either volumetric productivity or product recovery.

Abstract: A hollow fiber membrane module using a sheet-form hollow fiber membrane having excellent cleaning properties in which the pressure resistance of a hollow fiber membrane anchor section does not deteriorate, even when the membrane area increases; a hollow fiber membrane module unit using the module; a membrane filtration device using the unit; and an operation method therefor are provided. The hollow fiber membrane module comprises sheet-form hollow fiber membranes and an anchoring member which anchors the sheet-form hollow fiber membranes in a roughly parallel manner while maintaining in an open state at least one end portion of the sheet-form hollow fiber membranes. The shape of an end face of a side of the anchoring member from which the hollow fiber membranes are exposed is roughly rectangular, and the shape of an end face of a side of the anchoring member toward which the hollow fiber membranes open is roughly circular.

Abstract: A separation membrane module having hollow fibers, wherein a plurality of hollow fibers are heated and melted to bond and thermally fuse the external surfaces of the hollow fibers with each other; and a method of manufacturing a separation membrane module having hollow fibers whereby the ends of a plurality of hollow fibers are inserted into a sheath, the sheath and the hollow fibers are tightly bonded together to form spaces, and the sheath portion into which hollow fibers have been inserted is heated up to the temperature at which the surfaces of the hollow fibers melt, with the spaces thus formed kept in a decompressed state, so that the exterior surfaces of the hollow fibers are thermally fused and integrated together.

Abstract: An apparatus including a first hollow fiber membrane module, baffle assembly, and fluid source. The module includes a plurality of elongated hollow fiber membranes located generally in adjacent, parallel relationship to each other. Each of the membranes includes a generally cylindrical wall having a first end and a second end. The module also includes a module housing that supports the membranes. The module is configured to be positionable within the conduit and further to be matable with a similarly configured module. The baffle assembly is located within the conduit and configured to direct the flow of a first fluid through the module. The fluid source directs a second fluid to flow through the membranes from the first end to the second end. A predetermined substance is transmitted through the membranes' walls, to modify the concentration of the predetermined substance in the first fluid.

Abstract: The instant invention is a hollow fiber membrane contactor, and method of making same. The hollow fiber membrane contactor includes (1) a shell, said shell having a internal bonding surface, an interlocking geometry ring being provided on said internal bonding surface; (2) a unitized structure; (3) a potting material joining said unitized structure to said shell at said interlocking geometry ring thereby forming an interlocking seal therebetween; and (4) end caps, said end caps being adjoined to lateral ends of said shell. The method of making a hollow fiber membrane contactor includes (1) providing a shell, said shell having a internal bonding surface; (2) providing an interlocking geometry ring on said internal bonding surface; (3) forming a unitized structure; (4) placing the unitized structure into said shell (5) potting said unitized structure to said shell at said interlocking geometry ring thereby forming an interlocking seal therebetween; and (6) adjoining end caps to lateral ends of said shell.

Abstract: According to the module 10, the other end 22 of each of the plurality of porous cylindrical bodies 12 the one end 20 of each of which is closed is opened to the gas chamber 58 between the end cap 18 and the end cover 54, and the end cap 18 is provided with the through-hole 53 leading from the gas chamber 56 outward, and the gas chamber 58 leads outward by means of a path passing through the through-hole 53 and through the porous cylindrical body 12. The module 10 can have a gas-passing path from the peripheral wall 24 of the porous cylindrical-body 12 outward through the gas chamber 58 and through the through-hole 53.

Abstract: A method of supplying oxygen rich air to the passengers and crew on board a passenger aircraft by use of a highly permeable oxygen enrichment unit, wherein the fiber tubes of the hollow fiber membranes used to separate normal air into oxygen rich and nitrogen rich fractions in the oxygen enrichment unit are subjected to a modification technique before the tubes are coated with a selective polymer.

Abstract: A device for protecting medical apparatus from contamination by infectious agents comprises a containment body having an inlet destined to be set in fluid communication with an extracorporeal circuit of blood, and an outlet destined to be connected to a fluid line operatively connected to a pressure gauge of a medical apparatus. The inlet is in gas communication with the outlet across an internal cavity of the containment body. Two hydrophobic membranes are predisposed in the containment body between the inlet and the outlet. The membranes each define an anticontamination barrier which is gas-permeable. The device transmits the pressure of the extracorporeal circuit to the pressure gauge, with no relevant loss of head, while at the same time protecting, with a high degree of security, the medical apparatus from risks of contamination by pathogens originating in the extracorporeal circuit.

Abstract: A method of producing composite, hollow fibre gas separation membranes, wherein external surfaces of the porous hollow fibre tubes used in the construction of the membranes are subjected to a modification technique before the external surfaces are coated with a thin layer of selective polymer so as to increase the number of pores in the fibre surface.

Abstract: A mixed matrix membrane is provided which comprises a continuous phase organic polymer and small pore molecular sieves dispersed therein. The molecular sieves have a largest minor crystallographic free diameter of 3.6 Angstroms or less. When these molecular sieves are properly interspersed with a continuous phase polymer, the membrane will exhibit a mixed matrix membrane effect, i.e., a selectivity increase of at least 10% relative to a neat membrane containing no molecular sieves. Finally, methods for making and using such mixed matrix membranes to separate gases from a mixture containing two or more gases are also disclosed.

Abstract: An object of the present invention is to provide a humidifying apparatus capable of improving the humidification efficiency while lowering the pressure loss of gas even when a low-pressure gas is used, and is suitably usable for fuel cells. The present invention relates to a humidifying apparatus for fuel cells, fabricated by loading a hollow fiber membrane element into a container such that the space communicating with the hollow side of the hollow fiber membranes is isolated from the space communicating with the outer side of the hollow fiber membranes, wherein (a) the inner diameter of the hollow fiber membrane is larger than 400 ?m, (b) the water vapor permeation rate (P?H2O) of the hollow fiber membranes is 0.5×10?3 cm3 (STP)/cm2·sec·cm Hg or more, (c) the ratio (P?H2O/P?O2) of the water vapor permeation rate to the oxygen gas permeation rate of the hollow fiber membranes is 10 or more, and (d) the elongation at tensile break of the hollow fiber membranes after hot water treatment in hot water at 100° C.

Abstract: A process for controlling the volume of dry air, dried to a predetermined degree of dryness, from a sweep manifold of an air dryer system, flowing over a plurality of gas/liquid fluid separating membranes, comprising: diverting a predetermined volume of dried air to the manifold; sensing one of the flow volume and humidity values of the remainder of the dried air or the pressure differential within the system; and utilizing one of the differential pressure to control the predetermined volume of dried air and utilizing a controller for achieving the predetermined degree of dryness by controlling at least one solenoid valve which, in turn, controls the flow volume of the predetermined volume of dried air diverted to the manifold.

Abstract: An elongated flow-through degassing apparatus includes an elongated gas and liquid impermeable outer tube and one or more gas-permeable, liquid-impermeable elongated inner tubes extending within the outer tube and at least partially through a chamber defined within the outer tube. The apparatus also includes inlet and outlet connection structures operably coupled to respective portions of the outer tube and the inner tubes to further enable a sealed engagement between the outer tube and the inner tubes, and to provide for connection devices to operably couple the degassing apparatus of the present invention to respective spaced apart components. The degassing apparatus is sufficiently flexible so as to be readily manipulatable into desired configurations.

Abstract: A device or apparatus for contacting a liquid with a gas is provided. The device or apparatus has at least one gas inlet for introducing the gas into the liquid and a fiber housing with at least one liquid inlet and at least one liquid outlet. The fiber housing is surrounding and defining an outer bound for a plurality of fibers extending longitudinally in the fiber housing, whereby longitudinally extending interspaces are provided between the fibers. These interspaces thereby define flow passages for the liquid and gas. There is also provided a system and a method for contacting a liquid with a gas.

Abstract: Medical devices for removing gasses, such as gas bubbles and/or dissolved gasses, from a liquid to be delivered to a patient, and methods of use and making of such devices. In at least some embodiments, a gas permeable membrane material is used in the construction of the gas removal devices. In some embodiments, layers of gas permeable membrane material are used to construct a filter structure for removing gas from the liquid. In other embodiments, hollow tubes and/or fibers of the gas permeable membrane material are used to construct a filter structure for removing gas from the liquid. The gas removal devices may be used in any of a broad variety of liquid delivery systems and/or configurations.

Abstract: A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing protons or hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at dissociation temperatures the hydrogen from the dissociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the dissociation of steam producing hydrogen and oxygen. The oxygen is thereafter reacted with methane to produce syngas which optimally may be reacted in a water gas shift reaction to produce CO2 and H2.

Abstract: A hydrogen diffusion cell that is used to purify contaminated hydrogen gas. The hydrogen diffusion cell has at least one hydrogen diffusion structure that separates a first area from a second area. Normally, the pressure in the first area is kept higher than the pressure in the second area. This causes a pressure differential that causes hydrogen gas to permeate from the first area to the second area. However, an extreme pressure differential can occur when the second area is at its maximum pressure and the first area is inadvertently vented to ambient pressure. Under this extreme pressure differential hydrogen gas permeates from the second area back into the first area at a maximum reverse flow rate. A flow restrictor is provided that limits the flow of gas exiting the first area to a flow rate no greater than the maximum reverse flow rate.

Abstract: A method of separating or concentrating hydrocarbon-containing gas mixtures such as hydrogen from hydrocarbons, carbon dioxide from hydrocarbons, nitrogen from hydrocarbons, and hydrocarbons from one another using a selectively permeable membrane. The method is well suited to separate hydrocarbon-containing mixtures such as those generated by petroleum refining industries, petrochemical industries, natural gas processing, and the like. The membranes exhibit extremely good resistance to plasticization by hydrocarbon components in the gas mixture under practical industrial process conditions.

Abstract: The present invention provides a selectively gas permeable membrane that has a superior combination of permeability and selectivity. The membrane composition includes a Type 1 copolyimide uniformly blended with a Type 2 copolyimide, which polymers are defined by chemical structure more specifically in this disclosure. The invention also provides a method of using the membrane of the copolyimide blend to separate components of gas mixtures.

Abstract: The invention relates to a filter comprising membranes made of hollow fibers in which the hollow fibers are arranged as a bundle in a tubular housing. The housing comprises an end cap on each of its ends, whereby the hollow fiber bundle is placed between the ends of the housing. The ends of the hollow fiber bundle each comprise a support ring that surrounds the same and are cast inside said support ring. The support rings are displaceably mounted in the housing in order to compensate for, among other things, axial contractions of the hollow fiber bundle occurring during heat sterilization.

Abstract: A process for removing oxygen from a copper plating solution is provided. The solution is passed through a degasser comprising a shell and hollow hydrophobic fiber porous membranes wherein the shell while a vacuum is drawn on the surfaces of the fibers opposite the fiber surfaces contacted by the solution. Gas passed through the fiber walls while liquid is prevented from infiltrating the fiber pores. The composition of the solution is monitored so that the composition can be retained substantially constant by adding components of the solution as needed.