Abstract: A method suitable for treating used oil to remove ash and metal contaminants therefrom with minimum oxidation of the oil, the metal including at least one of the components of iron, lead, copper, zinc, sodium, magnesium, and calcium, to provide a highly purified oil product having less than 10 ppm of at least one of the contaminants and less than 0.15 wt. % of ash content. The method comprises providing a body of oil to be purified and chemically treating the oil to condition ash and metals contained therein to facilitate removal of ash and metal during membrane purification of the oil.

Abstract: A water desalination and softening system that can be used in a home or commercial environment which recirculates water past a membrane filter element in a manner to self clean the membrane and to prevent a buildup of salts and minerals on the membrane surface. The system conserves water so as to result in near zero waste by recirculating water from a reservoir tank past the membrane. The system can operate in conjunction with a building's water supply and can operate without problems in either a zero or low effluent mode or when water usage is frequent.

Abstract: Rubbery polymers in hydrocarbon solutions are emulsified in aqueous liquids and converted to latices by partitioning the emulsion through a membrane of selective permeability to the hydrocarbon solvent relative to both water and the polymer, thereby removing the hydrocarbon solvent from the emulsion. The foaming that is often associated with removing hydrocarbon solvent from aqueous emulsions by conventional means is thus avoided. Membrane partitioning mechanisms that are useful for this application include those involving both nonporous and microporous membranes, those passing the solvent both as a liquid and as a gas, those drawing off the permeate as both a liquid and a gas, and various combinations of these methods.

Abstract: This invention provides a method of filtering blood using a filtering material comprising glass fiber filter, capable of obtaining a desired amount of plasma or serum without hemolysis and leakage of blood cells easily which comprises keeping pressure difference between blood inlet side and filtrate outlet side 50 mmHg or less at least for 5 seconds from contacting the blood to be filtered, and keeping the pressure difference 200 mmHg or less throughout the filtering of the blood.

Abstract: A membrane filtration system which uses pump speed controllers to control flow rate and pressure during both the filtration cycle and the backwash cycle. The pump speed controllers operate by changing the frequency of AC current delivered to the pump motors, which changes the flow rate by changing the speed of the pump motor. The speed controllers operate by modulating the pump input power frequency in response to a signal from a flow or pressure signal received from a flow or pressure meter located on a liquid input pipe. This pump speed control method avoids the cyclical dampening patterns observed when trying to adjust pressure and/or flow rates by adjusting regulating valves. The system can also reduce or prevent formation of pressure spikes when switching from a filtration cycle to a backwash cycle, and vice versa. This reduces the likelihood of damage to the membrane from hydraulic pressure pulses.

Abstract: A reverse osmosis water purification system in which the concentrate water which is normally produced by the process is not disposed of by routing it to a drain line or otherwise, but is redirected to the main water supply. The system includes the well-known components of a reverse osmosis membrane, pre-filters which are installed ahead of the reverse osmosis membrane, and an appropriate tank to store the purified water. In addition, the system includes a pump and associated pressure sensor for increasing the pressure of the incoming non-processed water to the reverse osmosis unit, means for directing the concentrate water from the reverse osmosis unit to the incoming main water supply (cold), or to a hot water line. Additionally included is a one-way check valve in the concentrate water line, and a sensor sensing the pressure of water in the storage tank and turn the pump off whenever the pressure exceeds a predetermined value.

Abstract: A process is described for filtration of fluids, particularly of beverages like beer, utilizing microfiltration membrane modules operated in alternating filtering cycles and cleansing cycles, in which the cleansing cycles are always carried out when the transmembrane pressure exceeds a pre-set pressure which has been set to equal to the optimum trans-membrane pressure for the particular fluid being filtered, based on an analysis of the fluid after it has been filtered. In beer filteration, this value is preferably set at 1.5 bar. The microfiltration facility is equipped with numerous MF modules, arrayed in series and parallel; with a device for cleansing the MF modules and a measuring device for recording trans-membrane pressure that is attached to a control device which, upon attaining the pre-set trans-membrane pressure, interrupts the filtering cycle and starts a cleansing cycle.

Abstract: A method of adding or removing a gas to or from a solution of the gas in a liquid involves transferring the gas between the liquid and another fluid through a membrane unit. The membrane unit includes a membrane which is (i) substantially impermeable to the solvent and having a permeability to oxygen of at least 100 barrers; (ii) formed from an amorphous copolymer of perfluoro-2,2-dimethyl-1,3-dioxole; and (iii) is maintained at a temperature below the glass transition temperature of the copolymer. The fluid can be another liquid or a gas. The novel method provides very high rates of gas transmission between liquids and permits gasifying liquids without resort to sparging bubbles through the liquid. The method thus can gasify liquid with superior efficiency and without excessive agitation due to bubbling.

Abstract: A process recovers organic acid and ammonia from their salts preferably obtained from microbial fermentation of a saccharide in a nutrient. The fermented materials is passed through a nanofiltration or a chelating resin ion-exchange bed or a combination of both a nanofilter and a chelating resin ion-exchange bed in order to reduce divalent or multivalent metal contaminants. Then, the filtered material is processed in a multi compartment electrodialysis containing bipolar and anion membranes.

Abstract: This invention provides a process for checking the removal rate of pyrogenic substances, in particular viruses, from organic material. The material to be purified is passed through an ultrafilter or an ultrafiltration unit whose virus-removal rate has already been determined by passing viruses of the Leviviridae family or other comparable small bacteriophages through the filter or filtration unit, the virus titer is determined before and after the filtration operation and the virus removal rate thus calculated. Before or after determining the virus-removal rate, a given pressure is applied to the filter or filtration unit in a gas pressure-hold test, and the decrease in the pressure over a given period is measured. After filtration of the biological material, the rate of virus removal by the filter is checked by repeating the pressure-hold test.

Abstract: The present invention relates to methods and apparatus for reducing the fouling of ion-selective membranes used in the electrodialytic purification of organic acids. More particularly, the present invention relates to the use of nanofiltration and chelating agents for removal of impurities from an organic acid-containing feed material to reduce the fouling of ion-selective membranes used in electrodialysis.

Abstract: A reverse osmosis water purification system in which the concentrate water normally produced by the process is not disposed of by routing it to a drain line or otherwise, but is redirected to the main water supply. The system includes the well-known components of a reverse osmosis membrane, pre-filters which are installed ahead of the reverse osmosis membrane, and an appropriate tank to store the purified water. In addition, the system includes a pump and associated pressure sensing device for increasing the pressure of the incoming non-processed water to the reverse osmosis unit, and a pipe to carry the concentrate water from the reverse osmosis unit to the incoming main water supply, be it either a cold or hot water line. Additionally included is a one-way check valve in the concentrate water line, and a sensing device in the purified water storage tank to turn the pump off whenever the quantity of water in the tank exceeds a predetermined amount.

Abstract: A crude aqueous mixture of basic salts of an organic acid, free organic acid, and impurities is mixed with carbon dioxide under pressure and applied to a membrane such as a reverse osmosis or other membrane with small pores while holding the mixture under pressure with well mixed carbon dioxide, such that the free organic acid preferentially permeates the membrane while the impurities and salts of the organic,acid are preferentially but not necessarily completely retained. In The preferred form of the invention a back pressure is maintained on the permeate side of the membrane that is a significant pressure but less than the pressure applied to the feed side. This allows higher levels of acidification to be achieved. This is necessary as many membranes are permeable to CO.sub.2 choices of membrane permeate side pressure, retentate side pressure, and permeate counter flow rate can be used to effect different levels of either purification or concentration or both.

Abstract: Processes and apparati are provided for separating species of interest from a mixture containing them which comprises subjecting the mixture to tangential-flow filtration, wherein the filtration membrane preferably has a pore size that retains species with a size up to about 10 microns, and the flux is maintained at a level ranging from about 5 % up to 100 % of transition point flux.

Abstract: The invention provides a method of separating a biomacromolecule which comprises the steps of providing a separation system including a filter element which comprises a composite filtration medium, the composite filtration medium comprising a filtration layer on the upstream surface of which are located insoluble stationary phase particulates, the particulates being capable of binding to a biomacromolecule or class of biomacromolecules, a reservoir containing a solution mixture comprising at least one biomacromolecule as solute, and a pump and associated tubing to form a closed loop assembly, and recirculation pumping the solution mixture through the filter cartridge so as to bind the at least one biomacromolecule to the stationary phase particulate so as to form a biomacromolecule:stationary phase particulate product.

Abstract: Methods for adjustable separation of solutes and solvents involve the combination of the use of a maximally swollen membrane and subsequent vacuum depressurization exerted on the permeate side of that membrane. By adjusting the extent of depressurization it is possible to separate solvent from solutes and solutes from each other. Improved control of separation parameters as well as improved flux rates characterize the present invention.

Abstract: The invention provides a method for the solvent-extraction of .beta.-carotene from an aqueous algal biomass suspension, whereby a vegetable oil which is immiscible with water is mixed with an aqueous biomass suspension, the biomass containing the .beta.-carotene, to form a mixture of the organic phase and the aqueous suspension, whereby the .beta.-carotene is caused to dissolve in the organic phase. This is followed by separation of the organic phase from the aqueous phase by passing the organic phase containing the dissolved .beta.-carotene through a semi-permeable membrane to effect microfiltration or ultrafiltration of the organic phase. The membrane is of a material which is hydrophobic and the organic phase is passed through the membrane with a pressure drop across the membrane which is lower than that which causes the aqueous phase to pass through the membrane.

Abstract: A membrane separation and purification process, and the associated apparatus, provides separation of one membrane-permeable component from another, where both are contained in a multiple-component fluid mixture, as a dynamic function of the differences in respective rates of attainment of and declination from steady-state membrane permeation. The process and apparatus are equally well suited to multi-component fluid mixtures that are liquid or gaseous.

Abstract: Polymer is recovered by ultrafiltration from a whitewater waste stream generated during the production of a polymer latex. The whitewater stream is circulated through an ultrafiltration system in laminar flow, under conditions of shear insufficient to destabilize the whitewater emulsion, and the recovered polymer is in the form of an emulsion which may be blended at significant levels into the original polymer latex without degrading its performance properties.

Abstract: This invention relates to a reverse osmosis treatment process, particularly a stable reverse osmosis treatment process which prevents a lowering in throughput capacity by carrying out treatment while keeping the permeate flux of a reverse osmosis membrane constant through the time of use of a module. The process of this invention can keep the throughput capacity constant, can prevent adhesion and pollution onto membrane surfaces and fouling thereon, and moreover can maintain stable operation in a continuous run.

Abstract: This invention relates to cross-flow filtration and more particularly towards disposable, compact cross-flow filters and filtration methods incorporating a novel pressure-balancing arrangement comprising a flexible wall which expands and contracts in response to fluid pulsations. The invention further relates to methods of fluid concentration employing such a device to a fluid concentration system, and to methods of making such a filtration device.

Abstract: Processes and apparati are provided for separating species of interest from a mixture containing them which comprises subjecting the mixture to tangential-flow filtration, wherein the filtration membrane preferably has a pore size that retains species with a size up to about 10 microns, and the flux is maintained at a level ranging from about 5% up to 100% of transition point flux.

Abstract: A process for separating a mixture of aluminum alkyl and alpha-olefin comprises contacting, under an elevated pressure of at least about 300 psig, an organic solvent stable, polyphenylene oxide-derived membrane with said mixture and recovering as the permeate an alpha-olefin fraction which contains a lower concentration of aluminum alkyl than in the starting mixture.

Abstract: A single, reverse osmosis membrane system having a double-pass, product-staged design using first and second banks of membranes in series, with excessive pressure supplied by the pump to the feed to the first bank so that the concentrate flow from the first bank will be at sufficient elevated pressure to drive a turbocharger for increasing the low pressure product flow sufficiently to pass through the second bank of membranes, the excess pressure on the first bank being balanced by increased osmotic pressure from feedback of concentrate flow from at least one of the banks to the feed supply. Preferably, part of the concentrate flow from the first bank is dried on a double drum dryer or a single drum flaker for recycle use or disposal. The membranes for the first set are high rejection, high pressure membranes. The membranes for the second set are low rejection, low pressure membranes.

Abstract: A method of separating and recovering components of a mixture having a gap in the range of miscibility and having organic compounds and water in a pervaporization process with the aid of membranes. The mixture is first separated into an organically loaded water phase and a water-saturated organic phase. Subsequently, the organically loaded water phase and the water-saturated organic phase are separately subjected to parallel, different pervaporization processes, resulting in retentates as water on the one hand and organic liquid on the other hand. The permeates that result during the pervaporization processes are subsequently returned to the mixture that is to be separated.

Abstract: A method and systems for separating fluids of differing masses from a mixture by enhanced diffusion wherein the method and systems embody at least one cycle wherein the mixture of fluids of differing masses is fed into a first reservoir which is connected by at least one duct to a second reservoir; a carrier fluid is fed into a second reservoir; oscillatory axial movement of fluid within the at least one duct is established; a mixture of carrier fluid and a mixture of fluids of differing masses enriched in the component thereof having higher effective diffusion coefficient is withdrawn from the second reservoir; a mixture of carrier fluid and a mixture of fluids of differing masses enriched in the component thereof having the lower effective diffusion coefficient is withdrawn from the first reservoir; such that a positive flow of the carrier fluid is maintained from the second reservoir through the at least one duct into the first reservoir.

Abstract: The described apparatus is a multilayer liquid membrane support structure that can be used in devices for separating or purifying a desired chemical species. A inner layer is sandwiched between two outer layers to provide a porous support for a liquid membrane subject to oscillatory motion at a frequency selected to promote enhanced mass transport of the chemical species across the liquid membrane. The pores of the inner layer are selected to have an average pore diameter less than the pores of the outer layers.

Abstract: An apparatus for flow field flow (FFF) fractionation comprises: a porous hollow fiber (1) which extends longitudinally between end-fittings (2, 3) of a tube (4), one end of said fiber (1) being connected to a first pump (5) for pumping a first carrier liquid into said fiber (1) via a valve (9) for introducing a liquid sample to be fractionated, the other end of said fiber (1) being connected to a container for a second carrier liquid via a flow-through detector (11), for detecting fractions of said sample; a second pump (12) which is connected to the interspace between the tube (4) and the fiber (1) to pump out carrier fluid through the porous fiber wall; and a control unit (6) which is adapted to control said first pump (5) to have a flower flow rate than said second pump (12) during injection and relaxation of the sample, and a higher flow rate than said second pump (12) to elute the sample; and a method for FFF fractionation in a hollow fiber utilizing the steps of sample application, relaxation, flow rest

Abstract: An ultrafiltration system with a recirculating closed loop design and a feed control valve outside the loop which admits feed to the loop under permeate level control was shown to be operable with a constant recirculation flow thus minimizing membrane fouling. A fast flush was also possible without closing the permeate valve.

Abstract: In a process for clarification of liquids, especially raw juice by continuous crosscurrent filtration, which for improvement of the filtration output is run with a high solid portion in the retentate circulating circuit, during the starting phase an additional retentate discharge from the retentate circulating circuit takes place, which is relatively small in comparison with the retentate discharge taking place during the stationary operating phase. By this measure, a further improvement of the filtration output is achieved.

Abstract: The subject invention is directed to an apparatus for removing organic compounds from water which comprises: a housing having an opening therein, the housing being capable of retaining an organic solvent therein; and a nonporous membrane covering the opening, the membrane being capable of allowing organic compounds from the water to diffuse therethrough. The subject invention also provides method of removing organic compounds from water and a method for detecting the presence or determining the amount of organic compounds in the water.

Abstract: A method of separating and recovering components of a mixture having a gap in the range of miscibility and including organic compounds and water in a pervaporization process with the aid of membranes. The mixture is first separated into an organically loaded water phase and a water-saturated organic phase. Subsequently, the organically loaded water phase and the water-saturated organic phase are separately subjected to parallel, different pervaporization processes, resulting in retentates as water on the one hand and organic liquid on the other hand. The permeates that result during the pervaporization processes are subsequently returned to the mixture that is to be separated.

Abstract: A method of preparing a coupler dispersion in gelatin by separating the auxiliary coupler solvent using a hydrophobic microporous membrane and contacting the opposite surface of the membrane with a coupler solvent.

Abstract: A portable ultrafiltration device is disclosed comprising a prefilter, pump, membrane filter cartridges, temperature sensors, pressure sensors, process interdiction and control means placed to detect temperature and pressure variations of a feed mixture being processed by the device, and means cooperating with said temperature and pressure means to interdict the operation of the device to prevent damage to the components. Provision is also made for an improved feed mixture pick-up tube comprising a sliding gate means for interdicting liquid pick-up from an oil/water feed mixture.

Abstract: The microfiltration of a turbid liquid, especially the microfiltration of a fermentation liquid to recover beer from a suspension containing excess yeast is controlled by measuring a flow velocity (v) and a pressure drop (.DELTA.p) and calculating from the flow velocity (v) and the pressure drop (.DELTA.p) by an apparatus-characteristic function F (v, .DELTA.p) containing the flow velocity (v) and pressure drop (.DELTA.p) as variables a value of concentration of the turbidity-producing solids in the retentate stream. The value of the concentration as thus determined forms an actual value which is compared with a setpoint value of the concentration to determine a difference which is used to control the rate at which the concentrate stream is withdrawn from the retentate stream.

Abstract: A hemodiafiltration system which enables concurrent performance, in a single system, of hemodialysis and hemofiltration includes a dialyzer, consisting of a casing and at least one semipermeable membrane accommodated therein for dialyzing and purifying body fluid such as blood, plasma, etc., through contacting of the body fluid and dialyzate via the semipermeable membrane, and pumps for causing the dialyzate to flow through the dialyzer. A controller repeatedly changes the difference between the inflow amount of the dialyzate into the dialyzer per unit time and the outflow amount of the same from the dialyzer per unit time from a positive value to a negative value and then from negative to positive, whereby the repeated operation of taking or sucking out aqueous component or constituent and accompanying waste molecules from the body fluid followed by infusing or forcing a compensatory amount of dialyzate into the body fluid is made possible.

Abstract: In a process for transferring solute from a liquid feed solution to a liquid extractant which is substantially immiscible with the feed solution, one side of a porous membrane is contacted with the feed solution and the other side of the membrane with the extractant. One of the feed solution or the extractant preferentially wets the porous membrane. An interface-immobilizing pressure difference is maintained across the porous membrane in a direction and of a magnitude effective to oppose the tendency of the liquid which preferentially wets the membrane to flow through the membrane and disperse in the liquid on the opposite side. The interface between the feed solution and the extractant is thereby immobilized at the porous membrane.

Abstract: A apparatus and method for separating and purifying chemical species is presented. A supported liquid membrane is oscillated at frequencies sufficient to enhance the molecular diffusion of solute species across the supported liquid membrane.

Abstract: Systems and methods for predetermining maximum pressure differentials for particular microporous hollow fiber membranes and essentially immiscible feed and extractant liquids to be employed in liquid-liquid extractions include a test module having a number of such fibers formed into a loop between the opposing ends thereof. A tubular sleeve element encompasses these opposing ends, and a potting compound positionally retains the opposing ends within the tubular sleeve. The hollow fiber lumens are fluid-connected to a reservoir containing a pressurized feed liquid, and the loops of hollow fiber are immersed in an essentially unpressurized extractant liquid. The pressure of the feed liquid is continually increased until there is an incipient presence of the feed liquid in the extractant liquid. The pressure of the feed liquid at that incipient presence may therefore be used to calculate a maximum pressure differential tolerated by the microporous hollow fibers for the feed and extractant liquids used.

Abstract: A method for filtering a suspension including particulates and increasing the concentration of retainable matter wherein the suspension is drawn through the filter in a manner such that a portion of the suspension is subjected to a negative pressure which pulls it away from the filter membrane and permits it to pass through the filter unit without going through the membrane and a portion of the suspension is subjected to a positive pressure which causes it to pass through the filter membrane before exiting the filter unit, thereby creating a permeate. The invention involves regulation of flow rates to achieve a ratio of the pressures so that when some of the particulate matter from the portion of the suspension passing through the filter membrane becomes effective in decreasing flux, the negative pressure will serve to pull the particulate free and unclog the filter membrane on a continuous and automatic basis, thus allowing prolong filtration time with maximal flux.

Abstract: The invention is directed to an energy recovery pump turbine for use in industrial processes where a fluid is pumped at a high pressure to the process and at least a portion of the fluid is discharged from the process at a high pressure. A turbine is positioned to receive the high pressure discharge from the process. The turbine has an impeller positioned on a shaft and the discharged fluid engages the impeller and causes the impeller and shaft to rotate. A pump is position adjacent to the turbine to receive the fluid being pumped to the process. The pump has an impeller mounted on a shaft and the shaft of the pump is operatively connected to the shaft of the turbine. Rotation of the turbine shaft causes the impeller and the shaft of the pump to rotate whereby the pump assists in supplying the fluid under pressure to the process and to recover energy from the high pressure fluid discharged from the process.

Abstract: A desalination method and apparatus for separating permeate water (WP) from raw water (WF) pressure-fed by a pump (PM) through a reverse osmotic membrane module (U) to discharge concentrated water (WB) from an outlet valve (V2). When the membrane performance of the reverse osmotic membrane module (U) deteriorates due to formation of a gel layer (G). The number of revolutions of a pump driving motor (MO) is reduced and the opening of the outlet valve (V2) is increased, thereby increasing the flow velocity inside the reverse osmotic membrane module (U) so that the gel layer (G) is removed by the raw water (WF). Provided are a number-of-revolutions control means (1) for controlling the number of revolutions of the motor (MO), an opening control means (2) for controlling the opening of the outlet valve (V2) and an operation means (5) for operating the number-of-revolutions control means (1) and the opening control means (2) when the membrane performance of the reverse osmotic membrane module (U) is lowered.

Abstract: An object of the invention are macroporous polymeric membranes, suitable above all for the separation of polymers, which consists of the copolymer of a monovinyl monomer, selected from the group comprising acrylates, methacrylates, vinylpyridine, N-vinylpyrrolidone, vinyl acetate, and hydroxystyrene, with a divinyl monomer, selected from the group comprising alkylene and hydroxyalkylene diacrylates and dimethacrylates, divinylbenzene, and divinylpyridine, at the ratio of monomers of both types ranging from 5:95 to 95:5 wt. %. The membranes are formed from polymeric globular entities which have the size 0.05 to 0.5 .mu.m and are interconnected by covalent bonds, whereas communicating voids--pores occur between the globuli.The total thickness of membranes is 0.2 to 15 mm. and their specific surface area, which is measurable also in the dry state, may attain 400 m.sup.2 /g. Glycidyl methacrylate is advantageously used as the monovinyl monomer in the amount 5-80 vol. % related to the total volume of monomers.

Abstract: A process for separation of multicomponent mixtures of dicarboxylic acids, especially, mixtures of C.sub.8 -C.sub.24 saturated and unsaturated acids is derived from a fermentation process, in which an aqueous feed solution containing the mixture of dicarboxylic acids is adjusted in pH value depending on the permeability of the component to be separated and over 95% of the saturated component is separated from the unsaturated material by passing the mixture is content with a membrane filter.

Abstract: The instant invention provides a method and system for dehumidifying air by microphorous organic hollow fibers having a hygroscopic liquid disposed in the pores thereof for providing a concentration gradient sufficient to provide a continuous water removal mechanism.

Abstract: Surfactants present in water/oil/surfactant emulsions can be selectively separated from the emulsions by practicing an ultrafiltration process under specific conditions of pressure and ultrafiltration membrane pore size. It has been discovered that increasing the applied pressure results in an increase in the permeability of the surfactant without a commensurate increase in the permeability of the water or oil.

Abstract: The invention is a process for the separation of biotechnologically produced valuable materials from a fermenter broth by crossflow microfiltration and/or ultrafiltration, in which at least two modules arranged in series and fitted with porous membranes are used per stage, to produce concentrate and a permeate which contains the valuable material. The pressure of the permeate is controlled so that the absolute pressure on the permeate side is at different absolute pressure in each module.

Abstract: An adaptive filter concentrate flow control system and method includes a filter system, a pumping system driving feed fluid, concentrate and filtrate flowing through the filter system and a flow control system controlling the pumping system to maintain optimum filtrate flow rates along a control curve in a transmembrane pressure--feed fluid rate--filtrate flow rate three dimensional space. Actual sensed operating point data is used to locate the control curve so as to assure an optimized filtrate flow rate at which reversible blocking of the membrane has begun to occur without irreversible plugging. The system is advantageously employed to control and maximize the flow of plasma in a plasmapheresis system.

Abstract: A method of treatment of polluted emulsions or micro-emulsions (10) of oil in water, said method making use of tangential filtering through at least one membrane (1) constituted by a porous microfiltration structure which is constituted by titanium oxide, at least on the surface thereof. The method can be used to regenerate emulsions or micro-emulsions of oil in water.

Abstract: An analytical chemistry apparatus and method for introducing a reagent into a flowing stream of liquid carrier in order to quantitatively analyze one or more components of a sample added into the carrier. The reagent is permeated across a short section of membrane having relatively large pores. The use of such a membrane: (a) allows the membrane to be protected from physical damage by covering it with a perforate structure; (b) significantly reduces bandspreading across the membrane reagent addition device; (c) reduces the pressure drop across the membrane reagent addition device; and (d) still allows for the permeation of an effective amount of the reagent into the carrier. The reagent is preferably pressurized to minimize leakage of carrier across the membrane and the reagent can be self-pressurized by essentially completely filling the reagent reservoir of the invention with reagent and then hermetically sealing the reservoir.