Abstract: A method of reclaiming spent aqueous brine solutions used in the regeneration of water-softening resins. An aqueous solution chloride or other brine is acidified with HCl to a pH of between about 0.5 and 6 and a soluble sulfate salt, preferably Na.sub.2 SO.sub.4 is added, together with a precipitation inhibitor of the type polyacrylamide. Following such treatment, the spent brine is pumped at high pressure axially through a spirally-wound nanofiltration-type membrane device which is effective to remove at least about 90% of the divalent hardness while allowing passage therethrough of at least about 90% of the monovalent cations. As a result of such treatment, about 90 to 95% of the volume of spent brine can be efficiently and effectively reclaimed in a form in which it is suitable for use again in regenerating water-softening resins or the like.
Abstract: A sandwich of a permeate fabric material within a folded sheet of semipermeable membrane is spirally wound together with a sheet of porous feed pathway material about a mandrel which, upon its removal, provides a central hollow region in the wound element. A single band of adhesive seals the outer end of the envelope, and once wrapping is completed, a thin layer of porous tape holds the winding tight. A porous small diameter tube is inserted into a pocket adjacent the fold in the semipermeable membrane material near the center of the winding and serves as a permeate discharge conduit. Axial ends of the spirally wound subassembly are sequentially potted in resin to complete the basic fabrication of the element. Communication with the feed pathway material is provided by drilling through the resin into the center hollow region.
Abstract: Apparatus for the supply of decontaminated fuel to a diesel engine including two filtering stages, the first being a spiral wound, cross flow ultrafiltration unit and the second being a spiral wound deadheaded ultrafiltration unit with a pressure operated alarm connected to respond to the build-up of contaminants in said second stage.
Abstract: Cartridges for use in ultrafiltration or reverse osmosis separation devices are formed by injection molding a generally tubular, smooth, seamless shell about a spirally-wrapped semipermeable membrane assembly. These cartridges can be used within traditional separation devices having pressure vessels of precise interior diameter, for which the cartridges are uniquely suited because they have cylindrical surfaces of true circular cross-section and close tolerances. The cartridges can also be created so as to incorporate integral pressure vessels and thus permit their use in separation processes without the need for surrounding supporting pressure vessels. A reaction injection molding process is shown which provides for substantial efficiencies in the overall manufacturing of semipermeable membrane separation cartridges of the spirally-wound variety.
Abstract: A reverse osmosis or ultrafiltration separation device for treating a liquid feed wherein a separation assembly is wound spirally about a central permeate-carrying tube. The assembly includes an elongated semipermeable membrane envelope which includes an interior permeate passageway and feed-passageway-providing sheet material spirally wound with said envelope to supply a liquid feed to be treated. A cylindrical housing of circular cross section having an inlet and a pair of outlets holds the spiral wound separation assembly which is tightly surrounded by a seamless, highly porous, rigid, tubular sleeve proportioned to be snugly received within the cylindrical housing. The sleeve has a predetermined thickness relative to the diameter of the housing chamber so that a desired amount of bypass flow of liquid occurs through the space generally occupied by the sleeve.
Abstract: Disclosed are spiral-wound membrane cartridge constructions for use in ultrafiltration and reverse-osmosis separation equipment, each of which include a feed layer, a membrane layer and a permeate carrier layer. By using a feed layer in the form of a channel material having a plurality of parallel ribs extending in an axial direction, interconnected by a matrix of smaller filaments which may be generally perpendicular thereto, this construction advantageously reduces resistance to liquid frlow axially through the cartridge, registering only very low pressure drops. Such cartridges of 40 to 70 inches in length and 8 inches in diameter may be employed in series, even within a single outer casing or pressure vessel. Such constructions are especially useful in separating liquids having high levels of particulate contamination using ultrafiltration membranes where clogging of the cartridge is a common problem and also in concentrating solutions of fairly viscous water-soluble polymers.
Abstract: A spiral wound membrane cartridge for use in separating a first component from a feed fluid mixture of the first component and the second component. The cartridge includes a permeate collection tube and at least one permeate carrier leaf extending outwardly from the tube. The cartridge further includes at least one sandwich leaf extending outwardly from the tube and including a length of a semipermeable membrane sheet which has an active membrane side and a backing side. This sheet is folded in two, having the fold positioned adjacent the tube and with the membrane sides of the two parts of the folded sheet facing. The sandwich leaf also includes a length of a feed carrier positioned between the two parts of the folded membrane sheet.
Abstract: Disclosed are spiral-wound membrane cartridge constructions for use in ultrafiltration and reverse-osmosis separation equipment. The membrane constructions include a membrane layer directly bonded to a permeate carrier layer characterized by a channel material having a plurality of parallel ribs extending in a transverse permeate-carrying direction, interconnected by a relatively thin matrix of smaller fibrils. It advantageously reduces resistance to permeate flow to a central collection point, and can be employed to separate both liquid and gaseous fluids.
Abstract: Membranes of highly crystalline PTFE having an average pore size between about 0.01 micron and about 0.5 micron ordinarily reject any passage of water while allowing an organic nonpolar liquid to flow therethrough. By thoroughly wetting an expanded polytetrafluroethylene membrane with isopropyl alcohol, such a membrane will selectively allow the passage of a polar liquid, for example water, therethrough while rejecting other components, including nonpolar organic liquids, such as oil, kerosene or the like, and dissolved components of fairly large molecular size. Such IPA-wetted membranes are used to separate oil-water mixtures by allowing the water to selectively permeate through the membrane. The membrane may include a 5 mil thick backing layer of nonwoven synthetic fibers. The mixture is supplied to the membrane at a pressure not greater than about 90 psig., and often very low pressures of about 5-20 psig. can be used.
Abstract: An improvement in a membrane cartridge for insertion into a pressure-resistant container and having a central passageway holding a permeate collection tube. A cartridge is formed, at least in part, by a spiral winding of a laminate leaf comprising semipermeable membrane sheet material, permeate transfer sheet material, and porous grid sheet material. An extension on the leaf of the porous grid material is of sufficient length to encompass the circumference of the cartridge when the cartridge is positioned inside the container. The cartridge may have an outer wrapping of water-soluble sheet material.
Abstract: A reverse osmosis system including a proportioning flow control, for controlling brine flow from a pressure resistant vessel containing a membrane cartridge, which has ends of two small diameter duct portions enclosed inside a hollow body, which is separate from the pressure resistant vessel containing the membrane cartridge. Means, such as a unitary mass of solidified epoxy adhesive, seals the passage of each of the duct portions through a wall of the hollow body and leaves space within the hollow body with which the open ends of the small diameter duct portions communicate and which itself communicates with a relief valve connected to a collector or tank for storage of permeate from the membrane cartridge under elevated pressure.
Abstract: A semipermeable membrane cartridge is reciprocated within a pressure resistant vessel to provide improved liquid flow and turbulence over the semipermeable membrane surfaces. The end of the semipermeable membrane cartridge exposed to the pressure of feed liquid introduced into one end of the pressure resistant vessel is adjusted or arranged to be of substantially the same effective cross sectional area as that of the end of the cartridge exposed to the pressure of brine being released from the other end of the pressure resistant vessel. This essentially balances the liquid pressure forces on the ends of the semipermeable membrane cartridge to provide improved conditions for reciprocation.
Abstract: A reverse osmosis system employs a tank for storing permeate under a pressure which is a portion of the pressure of feed water introduced into a pressure resistant container housing a semipermeable membrane cartridge. Control means such as an automatic valve, preferably of the double diaphragm type, in the line introducing feed water into the pressure resistant container closes to shut off feed water flow when the pressure in the permeate storage tank reaches a first predetermined value, less than the feed water pressure, and re-opens to re-establish feed water flow at a second predetermined pressure lower than the first or shut-off pressure. A constricted passageway device such as a venturi in the pipe or connection between a dispensing device such as a faucet and the permeate storage tank has its throat communicating with the sensing conduit for actuating the feed water control valve.
Abstract: A process for recovery of fresh water by reverse osmosis from high salt content feed, such as sea water, comprises treating the feed water in an initial stage at relatively low pressure (between about 300 and 550 psi) employing a loose semipermeable membrane, to produce an intermediate product water containing one-fourth to one-half the TDS (total dissolved solids) content of the original feed water. The intermediate product water is treated in a subsequent stage also at a relatively low pressure (between about 300 and 550 psi) employing a tight semipermeable membrane, to produce a fresh product water containing less than 2,000 ppm TDS, and preferably a potable water containing less than 1,000 ppm TDS.
Abstract: A restrictor in the form of an elongated small duct or tube is employed for brine or concentrate flow control in a reverse osmosis system. The duct is composed of two portions, one end of one of these portions being connected to the brine output of a semipermeable membrane cartridge, and one end of the other of these two portions being connected to the brine disposal system. The other ends of both these duct portions communicate with the interior of a common compartment which, in turn, communicates through a pressure relief or check valve with the purified water collector of the semipermeable membrane cartridge. When the pressure in the purified water collector exceeds the pressure in the compartment, the check valve opens and purified water flows into the compartment and out through the portion of the elongated small duct or tube leading to concentrate disposal.
Abstract: A reverse osmosis apparatus includes a pump for pressurizing feed water introduced into a pressure resistant container in which is slidably mounted a semipermeable membrane cartridge. A rod, attached to an end of the semipermeable membrane cartridge, passes slidably and sealingly through one end of the pressure resistant container and is connected to means for reciprocal actuation. Means, preferably common, are provided to actuate the pump and the rod which imparts longitudinal reciprocal motion to the rod and the membrane cartridge within the pressure resistant container, thereby providing improved turbulence and circulation of the feed water through the semipermeable membrane cartridge over the membrane surfaces. The common means may be in the form of a lever operated by a handle or pedal, or by a power source such as an electric motor.
Abstract: A reverse osmosis apparatus comprises an elongated pressure container housing a plurality of semipermeable membrane cartridges in end-to-end relationship. A separate tap from the product water collector of the semipermeable membrane cartridge or cartridges nearest the inlet of the pressure container for introduction of pressurized feed liquid, produces a high quality water product. A tap from the product water collector of the remainder of the semipermeable cartridges in the pressure container produces a lower quality water product. A minor amount of high quality product water and a major amount of lower quality product water may readily be produced. The process and apparatus may advantageously be employed in the second or subsequent or final step of a multistage process for converting sea water to potable water.
Abstract: A spiral wound reverse osmosis or ultrafiltration membrane cartridge has a central collection tube fabricated from a plurality of interlocking segments; the center segments are perforated and the segment at each end is imperforate. The side edges of the cartridge membrane leaves and the permeate transfer sheet are sealingly attached to the central collection tube by circumferential bands of glue located outboard of the juncture of the imperforate end segments with adjacent perforate center segments. Substantial fabrication economies result from injection molding the center segments as identical bodies from a single die; and injection molding the end segments also as identical bodies from a single die.
Abstract: A combination faucet and antisyphon break or air gap for dispensing purified water produced by a membrane type purification unit, has a body having a valve-controlled passage with a spout for dispensing purified water; and a pair of additional vertical passages, one for connection to the brine output of the purification unit and the other for connection to the sewer. The passage connected to the brine output of the purification unit comprises a plastic tube which terminates at its top in a gooseneck, which acts as a channel to direct the brine overflow from this passage past an antisyphon break into the passage connected to the sewer. This passage also comprises a plastic tube.
Abstract: An improved spiral wound reverse osmosis or ultrafiltration membrane cartridge has the inner end and side areas of a permeate transfer leaf sealingly attached to its central collection tube surface, with sealing adhesive applied as band areas near each side edge of the proximate transfer leaf surface in amount in excess of the amount to substantially fill a pair of circumferential grooves in the collection tube when the assembly, including the permeate transfer leaf is spirally wound around it. The adhesive seal is preferably cured at room temperature with the cartridge standing on one of its ends for a period of about 12 to 24 hours. In an alternative embodiment, resilient O rings may be seated in the collector tube grooves, and an additional pair of grooves within the side band areas may also be filled with adhesive.