Abstract: An electrodeionization apparatus and process are provided for removing ions from liquids. Liquid to be purified is passed through depleting compartments containing mixed anion and cation exchange resin beads while a second liquid is passed through concentrating compartments free of ion exchange resin beads. Ions, under influence of a D.C. potential, pass from the depleting compartments into the concentrating compartments through ion permeable membranes. The beads in the depleting compartments are housed within subcompartments of controlled width and thickness and are retained therein by the ion permeable membranes which are secured to the walls of the subcompartments.

Abstract: A composite porous membrane is formed from a porous polymeric membrane having desired bulk properties on which is directly coated a cross-linked polymer having desired surface properties. The composites membrane retains the porosity of the porous polymeric membrane. A preferred composite porous membrane is formed from a porous polyvinylidene fluoride to which is directly coated with a polymer formed of a cross-linked hydroxyalkyl acrylate.

Abstract: Water substantially free of pyrogens and microorganisms that meets the requirements of United States Pharmacopoeia Standard USP XX Water for Injection is produced by processing drinking quality water through a filtration step adapted to remove organic contaminants and impurities that degrade downstream seperation membranes, a reverse osmosis step to remove dissolved solids, pyrogens, microorganisms and chemical contamination, a deionization step to further remove dissolved solids, and an ultrafiltration step to remove pyrogens. A sterile filter to remove microorganisms increases the water quality to USP XX Sterile Water for Injection. Means are provided to periodically remove accumulated chemical contaminants, pyrogens and microorganisms from the reverse osmosis apparatus, the deionization apparatus and the ultrafiltration apparatus. The sterile water can be admixed with a sterile concentrate composition to produce a sterile dilute solution that can be packaged under sterile conditions.

Abstract: Apparatus for metering liquids in controlled proportions and for delivering the resultant mixture to a point of use. The disclosed apparatus is particularly suitable for use in liquid chromatography applications. In one embodiment a plurality of reservoirs each containing a liquid to be mixed are connected through respective hydraulic accumulators to a switching valve arrangement for modulating solvent composition to the inlet of a high pressure pump. A flow and composition controller sequentially activates each of the switching valves such that the non-uniformity associated with the pump draw stroke is effectively averaged over several cycles of switching valve actuation. Such averaging is accomplished by generating and maintaining a fixed relationship between switching valve cycles and pump cycles which ideally is expressed as a non-integer ratio.

Abstract: A system for photometric measurement of optical properties of a fluid medium utilizing multi-wavelength excitation includes a movable diffraction grating that is continuously oscillated over the spectral range of interest and a flashlamp producing high intensity, short duration flashes. The angular position of the grating at the time of a flash determines what wavelength of optical energy will be passed to the remainder of the system. Because the flash duration is brief in relation to the period of movement of the grating, the flash effectively freezes the motion of the grating allowing the high intensity output of the flashlamp to be supplied to the fluid medium, while successive flashes permit measurement at many different wavelengths in near simultaneous fashion. The system is disclosed for use in an absorbance detector for liquid chromatography.

Abstract: A disposable, one-piece cap for a liquid container includes a frangible septum which allows easy penetration by a syringe needle to permit withdrawal of the liquid. The septum includes a plurality of grooves which are thinner than the thickness of the remainder of the septum to facilitate tearing of the septum as the needle penetrates. Such tearing prevents a seal from forming around the needle and thus allows air to enter the container avoiding problems associated with the formation of a partial vacuum within the container as the sample is withdrawn.

Abstract: Apparatus for oxygenating blood or for separating whole blood into a plasma fraction and an enriched plasma-depleted blood fraction comprising at least two contiguous membrane units, each unit consisting of a first membrane layer, a second membrane layer, a first spacer layer and a second spacer layer. The membrane layers and the spacer layers are configured so that only plasma or oxygen passes through the membrane layers from or into whole blood. Plasma and plasma-deplected blood or oxygen-depleted gas and oxygenated blood are separately collected while preventing admixture thereof with whole blood.

Abstract: Apparatus is provided for converting rotational motion to linear motion which includes a screw shaft and nut surrounding the screw shaft, each having a helical thread. A plurality of threaded planetary rollers is interposed between and in contact with the threads of the screw shaft and nut. A secondary locking thread-locking threaded path system is formed on two adjacent or all of the screw shaft, nut and planetary rollers to provide stable rotation and to maintain the planetary rollers in place. The screw shaft can have the same or a different number of starts than the number of starts on the nut.

Abstract: A multiwell apparatus for the assay of microliter quantities of body fluids is provided which prevents fluid loss by lateral migration or gravity flow through a microporous membrane or ultrafilter. A sample is passed through a membrane to which an antibody has been bonded in order to harvest complementary viral antigens in the sample. The harvested viral antigen is converted to single strand DNA or RNA which then is deposited on a second membrane. The deposited single strand DNA or RNA is capable of reacting with labeled DNA or other suitable detection probe which can be detected and correlated with antigen concentration in the sample.

Abstract: A filter apparatus is provided which is adapted for filtration of intravenous liquids and separates gas in the incoming intravenous liquid prior to delivering the filtered liquid to a patient. Incoming liquid is passed into a space within a filter holder, which space has a smaller portion that excludes gas due to surface tension forces and a larger portion where gas accumulates. A hydrophobic filter membrane is positioned adjacent the large portion of the space to permit passage of gas from the space. A hydrophilic filter membrane is positioned within the space to filter the liquid prior to administration to the patient.

Abstract: An interconnector 22 for filtration modules 18 which have axially extending tubes 90. The interconnector 22 is a rigid tubular member having conical tapered portion 88 at opposite ends to join fluid tight connections with the filtration modules.

Abstract: A magnetic flowmeter of the capacitively-coupled type includes low-input impedance detection circuitry which responds to a flow induced current signal that is related to the voltage induced at the electrodes by the intersection of the flowing fluid and a time varying magnetic field. An on-line measure of the electrode capacitance that is non-interactive with the flow induced current signal is accomplished by creating a voltage difference between the process fluid and the electrodes which causes a capacitance-related current to flow from the electrodes proportional to the value of the electrode capacitance as well as the rate of change of the magnetic field. In one embodiment the primary element and the detection circuitry are referenced to a different potential than that of the process fluid and the adjacent piping of the flow system.

Abstract: An improved method and structure for sealing the ends of a tubular filter element is described. The method comprises providing a strip on non-porous film along the edge of a sheet of microporous filter material, the strip being joined to the filter material fluid-tight at its outer portion but forming a free flap on its inner portion, forming the element with the strip at one end and over the upstream side of the filter material, embedding the end in liquid sealer to a depth terminating over the flap portion of the strip, and solidifying the sealer. A similar procedure is described for seaming the axially-extending side edges of a cylindrical element.

Abstract: Control of multiple distillation columns for producing anhydrous alcohol suitable for blending with gasoline to produce gasohol. The distillation process involves production of a first-stage distillate containing a predetermined amount of water, followed by azeotropic distillation in the presence of a hydrocarbon entrainer to strip the distillate of its water content, leaving anhydrous alcohol as a bottom product. Tight controls are present during first-stage distillate production to hold its proof at an optimum value derived at through material balance calculations to minimize energy consumption for the overall system. Control over the dehydrating stage is accomplished by a combination of ratio control to regulate and maintain the proper proportion of the entrainer and temperature control to regulate within the column the actual inventory of entrainer.

Abstract: Novel photometric apparatus advantageously having a conical shaped flow-cell comprising a light source proximate the narrow end and a photosensitive detector at the wider end of the cell. The flow-cell adequately compensates for a lens effect that has been discovered to be a substantial factor in electro-magnetic energy absorption studies on liquid streams. A light beam from the light source is passed through an elliptical aperture to render the beam substantially circular prior to entering the flow-cell.

Abstract: Novel membrane filter units are disclosed which are adapted for stacking and bonding into integral, disposable cartridges, optionally including an integral disposable housing. The units comprise a thin plastic support having flat membranes permanently bonded to their upper and lower surfaces. The support has a central opening, a sealing rim, and on each surface, inner and outer circumferential lands and intervening ribs or similar projections, the membranes being bonded and sealed to the lands and ribs. Each support surface adjacent the central opening has circumferential coupling and spacing means for bonding stacked units together in spaced relation. A novel method for bonding a membrane to a support is also disclosed.

Abstract: A water treatment cartridge and method for producing ultrapure water is described. The cartridge comprises a container having therein a particulate admixture of activated carbon and mixed bed ion exchange resins. A source of water, preferably pretreated, is passed through the container, preferably following treatment by one or more cartridges containing mixed bed ion exchange resins. The carbon in the admixed cartridge removes residual organic contamination from the water and the resins remove ionic contamination from the carbon, without re-introducing organic material to the water.

Abstract: A composition suitable for manufacturing into wear-resistant and chemically-inert articles, the composition being a mixture of 74 to 84% polytetrafluoroethylene, 7-17% graphite fibers, and 4-14% fluorinated graphite.

Abstract: Analysis of hydrocarbon mixtures to determine desired characteristics, particularly a determination of octane number of gasolines, undergoing partial oxidation/cool flame reactions. Pre-analysis performed on a target fuel sample of known composition and octane number is utilized to arrive at an optimum point of the reaction, a point believed to represent a condition where a maximum of the fuel is oxidized during the reaction. In the preferred embodiment disclosed, the optimum point is the reactor block temperature that generates a maximum peak temperature rise of the cool flame reaction of the target fuel. This optimum reactor temperature is utilized in further analyses of other known samples to develop a matrix of peak temperature rise versus time to reach peak coordinates. Any unknown fuel sample whose peak amplitude/time coordinate is within the matrix is compared with matrix values to determine its octane number as well as an indication of its composition.

Abstract: A non-imaging optical energy transfer system includes a tapered light pipe and associated field lens as its central energy transfer mechanism. The light pipe/lens combination is located between two separate sections of the system which individually have the same throughput or etendue but otherwise differ in f/#, beam focus, and pupil sizes. The transfer system is disclosed used in combination with a circular variable filter-absorption cell infrared spectrometer and an internal reflection spectrometer, employing a multiple internal reflection crystal.