Solid Sorption Patents (Class 95/90)
  • Patent number: 6136069
    Abstract: A method of separating a more strongly adsorbable component from one or more less strongly adsorbable components residing in a gaseous mixture comprising contacting the gaseous mixture at elevated pressure with a composition and adsorbing the more strongly adsorbed gas specie on the composition, wherein the composition is represented by the formulaM.sup.n+.sub.(2x+y)/n [Si.sub.(2-x-y) Al.sub.(y) Zn.sub.(x) ]O.sub.4 ;whereinM is cation selected from Groups 1, 2, 7, 10, 11, 12 and the f block elements as defined by thePeriodic Table of the elements as adopted by IUPAC;n is the valence of the selected cation; M;x is greater than or equal to 0.02 but less than or equal to 1;y is a value less than or equal to 0.98; and2x+y is greater than or equal to 0.80;wherein the composition of matter has a FAU structure and zinc resides in.sub.-- tetrahedral positions in the framework of the FAU structure.
    Type: Grant
    Filed: December 6, 1999
    Date of Patent: October 24, 2000
    Assignee: Air Products and Chemicals, Inc.
    Inventors: James Edward MacDougall, Thomas Albert Braymer, Charles Gardner Coe
  • Patent number: 6132492
    Abstract: A sorbent-based gas storage and dispensing system, including a storage and dispensing vessel containing a solid-phase physical sorbent medium having a sorbate gas physically adsorbed thereon. A chemisorbent material is provided in the vessel to chemisorb the impurities for gas phase removal thereof in the storage and dispensing vessel. Desorbed sorbate gas is discharged from the storage and dispensing vessel by a dispensing assembly coupled to the vessel. The chemisorbent may be provided in a capsule including an impurity-permeable, but sorbate gas-impermeable membrane, and installed in the vessel at the time of sorbent material loading. Semiconductor manufacturing processes and products manufactured by such processes are described.
    Type: Grant
    Filed: May 21, 1998
    Date of Patent: October 17, 2000
    Assignee: Advanced Technology Materials, Inc.
    Inventors: Steven J. Hultquist, Glenn M. Tom, Peter S. Kirlin, James V. McManus
  • Patent number: 6080281
    Abstract: Disclosed is a method for separating a vaporous or gaseous contaminant from an air stream contaminated therewith. This method includes the steps of: (a) passing said contaminated air into a contact zone in which is disposed an aerogel material capable of selecting adsorbing said contaminant from air and therein contacting said contaminated air with an aerogel material; and (b) withdrawing from said zone, air depleted of said contaminant. For present purposes, "contaminant" means a material not naturally occurring in ambient air and/or a material naturally occurring in air but present at a concentration above that found in ambient air. Thus, the present invention scrubs (or treats) air for the purpose of returning it to its ambient composition.
    Type: Grant
    Filed: December 8, 1995
    Date of Patent: June 27, 2000
    Inventor: Yosry A. Attia
  • Patent number: 6060032
    Abstract: A process is set forth for the production of a carbon monoxide stream from a feed stream comprising carbon monoxide, hydrogen, carbon dioxide, methane, nitrogen and moisture. The process comprises contacting the feed stream at elevated pressure with a layered adsorbent bed comprising (i) a pretreatment adsorbent in order to adsorb moisture preferentially over methane, nitrogen and carbon dioxide and (ii) a main adsorbent in order to adsorb carbon monoxide preferentially over hydrogen, carbon dioxide, methane and nitrogen. A key to the present invention is that a carbon-based adsorbent is used as the pretreatment adsorbent.
    Type: Grant
    Filed: July 27, 1998
    Date of Patent: May 9, 2000
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Christopher Thomas Hable, Timothy Christopher Golden, Wilbur Clymer Kratz
  • Patent number: 6030598
    Abstract: An ozone containing gas stream is produced from oxygen by subjecting oxygen to an electric discharge and the ozone is then adsorbed on to a solid adsorbent, such as zeolite, the oxygen containing stream leaving the adsorbent is recycled to the ozonising process. Periodically, oxygen adsorbed on the adsorbent is desorbed by co-currently passing a purge gas over the adsorbent and the desorbed oxygen is also recycled to the ozoniser. Lastly ozone is desorbed from the adsorbent by a counter-current flow of purge gas and used in an ozone demanding process.
    Type: Grant
    Filed: June 8, 1998
    Date of Patent: February 29, 2000
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Anthony K. J. Topham, Rodney J. Allam
  • Patent number: 6017508
    Abstract: A process of modifying the porosity of an aluminosilicate or silica whose porosity is not amenable to modification by acid extraction. The process involves contacting said aluminosilicate or silica with an alkali aluminate, and then extracting the aluminate-treated material with an extraction agent so as to form the porosity-modified aluminosilicate or silica. The process is applicable to zeolites which are unreactive under acid extraction conditions, e.g. ferrierite, and applicable to zeolites which are structurally unstable under acid extraction conditions, such as the mineral bikitaite. Mesoporous compositions are disclosed, including a mesoporous ferrierite and a mesoporous zeolite DCM-3.
    Type: Grant
    Filed: April 20, 1998
    Date of Patent: January 25, 2000
    Assignee: The Dow Chemical Company
    Inventors: Dean M. Millar, Juan M. Garces
  • Patent number: 5993766
    Abstract: A system for the storage and delivery of a sorbable fluid, comprising a storage and dispensing vessel containing a sorbent material having sorptive affinity for the sorbable fluid, and from which the fluid is desorbable by pressure-mediated and/or thermally-mediated desorption, wherein the sorbent material is functionally enhanced by a reagent which alters the binding energy of the fluid to the sorbent. In a preferred aspect, the system is arranged for storage and delivery of B.sub.2 H.sub.6, in which the sorbent material has sorptive affinity for B.sub.2 H.sub.6 and is effective when B.sub.2 H.sub.6 is contacted with the sorbent to convert B.sub.2 H.sub.6 to a sorbed .BH.sub.3 form, which is desorbable by pressure-mediated desorption and/or thermally-mediated desorption to release B.sub.2 H.sub.6 from the sorbent, and means for selectively discharging desorbed B.sub.2 H.sub.
    Type: Grant
    Filed: May 20, 1997
    Date of Patent: November 30, 1999
    Assignee: Advanced Technology Materials, Inc.
    Inventors: Glenn M. Tom, James V. McManus
  • Patent number: 5968232
    Abstract: A process for the separation of ammonia dissolved in a gaseous solvent is used to recover ammonia during the production of ammonia from a synthesis gas. The process may be used to extract and recover ammonia in either the supercritical region or the subcritical region. The process can be used to remove ammonia from synthesis gas, or other gaseous solvents, by removing ammonia whose chemical potential decreases as the density of the solvent increases. The process utilizes a sorbent to remove the ammonia followed by an in situ regeneration of the sorbent and recovery of the ammonia. Typically, a gaseous solvent containing the ammonia is passed through a bed of sorbent to sorb the ammonia onto the bed of sorbent, thereby producing a purified gaseous solvent. At least a portion of the gaseous solvent is then acted upon to increase its solvent capacity for the ammonia.
    Type: Grant
    Filed: July 22, 1997
    Date of Patent: October 19, 1999
    Inventor: David R. Whitlock
  • Patent number: 5858065
    Abstract: Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; providing at least one size selective membrane having a feed side and a permeate side; contacting the feed side of the at least one membrane with the gas mixture; withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.
    Type: Grant
    Filed: January 16, 1997
    Date of Patent: January 12, 1999
    Assignee: American Air Liquide
    Inventors: Yao-En Li, Joseph E. Paganessi, David Vassallo, Gregory K. Fleming
  • Patent number: 5824140
    Abstract: A canister including an elongated hollow plastic body having a wall with inner and outer surfaces, an edge portion on the wall defining an open end, an end on the edge portion extending transversely to the inner and outer surfaces, a porous plastic member having an outer edge portion extending across the open end and fused to the end, an inner portion on the porous plastic member located radially inwardly of the outer edge portion and extending into the body and fused to the inner surface of the wall adjacent the end thereof, and a gas-treating material in the body. A method of fabricating the above canister including the steps of applying pressure and vibratory welding energy to the porous member to thereby cause the member which was originally planar in shape to have its outer edge compressed against the end of the body and fused thereto and the central portion inwardly of the outer edge forced into the body and its outer edge fused to the inner surface of the body adjacent the end.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: October 20, 1998
    Assignee: Multisorb Technologies, Inc.
    Inventor: Lora L. Berger
  • Patent number: 5814129
    Abstract: Apparatus and method to improve flow of fluid through an annular bed in a radial flow treatment vessel. An elongated annular baffle is disposed in the reactor adjacent the bed to impart generally U-shaped flow to the fluid either prior to entering or after it exits the bed thus achieving an overall serpentine or reverse U-shaped flow pattern as the fluid proceeds from an entry port to an exit port in the reactor. Means are provided in the baffle to permit minor amounts of fluid to bypass the generally U-shaped flow path in order to correct fluid flow maldistribution through the bed that is attributed to frictional pressure drop in the flow channels adjacent to the bed. A vessel according to the invention can be operated with fluid flow through the vessel in either direction.
    Type: Grant
    Filed: April 11, 1997
    Date of Patent: September 29, 1998
    Assignee: Air Products and Chemical, Inc.
    Inventor: Stephen Clyde Tentarelli
  • Patent number: 5750030
    Abstract: It is proposed to use a synthetic granulate or powder with a particle size of 0.1 to 10 mm as packing material for the removal of liquid, gaseous and/or dissolved constituents from a process stream, which packing material is made up of a porous, preferably dimensionally stable polymer having an overall porosity of 50 to 95% by volume, which when used as an extracting medium has pores of a diameter of 0.01 to 50 .mu.m, with an extracting liquid immobilised therein, or when used as a coalescence medium has a cellular body/window structure with the diameter of more than 50% by volume of the bodies being in the range of 100 to 700 .mu.
    Type: Grant
    Filed: August 16, 1996
    Date of Patent: May 12, 1998
    Assignee: Akzo Nobelnv
    Inventors: Elwin Schomaker, Johannes Bos, Erik Leonard Middelhoek
  • Patent number: 5744687
    Abstract: A hydrocarbon stream is cracked to produce a hot gaseous stream which is compressed and cooled to condense almost all of the hydrocarbons contained in the stream. A noncondensed stream remaining after the condensation step, comprised predominantly of hydrogen and C.sub.1 to C.sub.3 hydrocarbons, is subjected to pressure swing adsorption or temperature swing adsorption at an adsorption temperature of about 0.degree. to about 250.degree. C. in a bed of adsorbent which selectively adsorbs ethylene and propylene, thereby adsorbing substantially all of the ethylene and propylene from the gas stream. The ethylene and/or propylene is recovered upon bed regeneration.
    Type: Grant
    Filed: April 22, 1994
    Date of Patent: April 28, 1998
    Assignee: The BOC Group, Inc.
    Inventors: Ramakrishnan Ramachandran, Loc H. Dao
  • Patent number: 5730785
    Abstract: A canister for a desiccant or other particulate material including a substantially cylindrical molded plastic body having an integral end wall and an inner surface and an open end, a cap having an inner surface and a portion which enters the open end of the body and is retained therein by a bead and groove connection, desiccant in the canister, and very small apertures in the cap and end wall, the apertures diverging in diameter from the inner surfaces of the cap and end wall toward the outer surfaces thereof to thereby tend to impede passage of the desiccant out of the canister and also tend to obviate clogging of the apertures.
    Type: Grant
    Filed: April 1, 1993
    Date of Patent: March 24, 1998
    Assignee: Multisorb Technologies, Inc.
    Inventors: Ronald C. Idol, Joseph L. Iwaniszek
  • Patent number: 5730779
    Abstract: A method for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by contact of the gas stream with a membrane, comprising the steps of: compressing a gas stream containing a diluent gas and fluorochemicals to an elevated pressure; heating the gas stream containing a diluent gas and fluorochemicals to an elevated temperature sufficient to increase the flux of the permeate stream and to increase the selectivity of the membrane for the permeation of the diluent gas relative to the permeation of the fluorochemicals; contacting the gas stream with a membrane which is selectively more permeable to the diluent gas than the fluorochemicals to result in a permeate stream rich in the diluent gas and a retentate rich in fluorochemicals; contacting the gas stream with one or more additional membranes which are selectively more permeable to the diluent gas than the fluorochemicals to result in a second permeate stream rich in the diluent gas and a second retentate
    Type: Grant
    Filed: October 31, 1996
    Date of Patent: March 24, 1998
    Assignee: Air Products and Chemicals, Inc.
    Inventors: Iosif Chernyakov, Thomas Hsiao-Ling Hsiung, Alexander Schwarz, James Hsu-Kuang Yang
  • Patent number: 5716427
    Abstract: The equipment, for example of the PSA type, comprises gas circulation elements for passing the gas horizontally through an adsorbent (3), which comprise, on at least one vertical side of the adsorbent, a gas distribution volume comprising a first subvolume (5; 9) adjacent to the adsorbent, and a second subvolume (6; 10) separated from the first subvolume by a wall provided with passages (40) having cross-sections and/or a distribution which are selected so as to reduce the variations in local flow rate along the adsorbent. The equipment is particularly useful in separating gases from air.
    Type: Grant
    Filed: August 15, 1996
    Date of Patent: February 10, 1998
    Assignee: L'Air Liquide, Societe Anonyme Pour L'Etude et L'Exploitation des Procedes Georges Claude
    Inventors: Philippe Andreani, Christian Monereau
  • Patent number: 5713985
    Abstract: A multi-function separator provides a coalescing section for removal of entrained impurities in a process stream; an adsorbent section for removal of vapor contaminants; and a filter section for removal of particulate impurities. A process stream flows into longitudinal hollow centers of porous coalescer robes and radially out; through holes in a baffle; into an adsorbent section; through a redistribution baffle; into filters; and out through another redistribution baffle. The multi-function separator is designed so that the process stream flows transverse to the longitude of an elongate vessel. The fluid velocity within the coalescer section is equal throughout, so that localized high-velocity areas are avoided, thus preventing re-entrainment of a coalesced contaminant.
    Type: Grant
    Filed: February 12, 1996
    Date of Patent: February 3, 1998
    Inventor: Boyd Lynn Hamilton
  • Patent number: 5676737
    Abstract: A process for the separation of solutes dissolved in a gaseous solvent. The process may be used to extract and recover solutes from solvents in either the supercritical or subcritical region. The process can be used to purify solvents containing solutes by removing solutes whose chemical potential decreases as the density of the solvent increases. The process utilizes a sorbent to remove the solute followed by an in situ regeneration of the sorbent and recovery of the solute. Typically, a gaseous solvent containing at least one solute is passed through a bed of sorbent to sorb at least one of the solutes to the bed of sorbent, producing a purified gaseous solvent. At least a portion of the gaseous solvent is then acted upon to increase its solvent capacity for the at least one sorbed solute.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: October 14, 1997
    Inventor: David R. Whitlock
  • Patent number: 5675050
    Abstract: Crystalline microporous solids of the aluminophosphate type consisting of MeAPO-FAU and MeAPSO-FAU with Me denoting a metal which can adopt tetrahedral coordination in an oxide, for example Co and Zn. The solids are synthesized by hydrothermal crystallization of a gel containing the elements Me, Al, P or Me, Al, P and Si and a structuring agent consisting of a mixture of tetrapropylammonium and tetramethylammonium cations. These solids can be employed in adsorption and also as catalysts in the conversion of organic compounds such as hydrocarbons.
    Type: Grant
    Filed: January 30, 1995
    Date of Patent: October 7, 1997
    Assignee: Elf Aquitaine
    Inventors: Thierry Des Courieres, Joel Patarin, Jean Louis Guth, Ligia Sierra
  • Patent number: 5669959
    Abstract: A process is disclosed for the shut-down of a membrane separation zone comprising a non-permeate side and a permeate side and processing a feed stream comprising a non-permeable component, a less-readily permeable, condensible component, and a readily permeable component. When the feed stream is not passed to the membrane separation zone, a purge stream is passed to the non-permeate side of the membrane separation zone to remove a residual gas stream and thereby prevent condensation of the less-readily permeable, condensible component upon depressurization and/or cooling of the membrane separation zone. The invention reduces the need for oversizing membrane system which reduces treating costs and prevents permeate damage to membrane surfaces caused by condensation of less-readily permeable, condensible components such as C.sub.6.sup.+ hydrocarbons.
    Type: Grant
    Filed: May 16, 1996
    Date of Patent: September 23, 1997
    Assignee: UOP
    Inventors: Kishore J. Doshi, William B. Dolan
  • Patent number: 5616169
    Abstract: A seal-free and frame-free odor and/or pollutant filter, e.g., in air conditioners and motor vehicles, having a self-supporting and elastic adsorption filter bed installed under slight compression in air supply ducts. The filter bed is made of a highly air-permeable substrate material and an adsorbent affixed thereto by an adhesive mass.
    Type: Grant
    Filed: June 19, 1995
    Date of Patent: April 1, 1997
    Assignees: Hasso von Blucher, Ernest de Ruiter
    Inventors: Ernest de Ruiter, Jonas Tornblom
  • Patent number: 5599381
    Abstract: A process is described for the separation of solutes dissolved in a gaseous solvent. The process is useful in the extraction and recovery of solutes using supercritical fluid extraction, and in the purification of impure steam. The process utilizes a sorbent to remove solute followed by an in situ regeneration of the sorbent and the recovery of the solute.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: February 4, 1997
    Inventor: David R. Whitlock
  • Patent number: 5529609
    Abstract: An air cleaner comprises a cleaning element having a three-dimensional visco-elastic matrix of material for adsorbing airborne particulate matter and for absorbing volatile liquids and a variety of noxious gases. The three-dimensional visco-elastic matrix of material adsorbs particulate matter of many types and sizes and advantageously draws the particulate matter below the surface of the material. To enhance the cleaning properties of the material, the three-dimensional visco-elastic matrix of material may additionally comprise a zeolite to improve the absorption of gases and a metallic additive, such as copper sulfate, to inhibit biological activity. The material forming the three-dimensional visco-elastic matrix may be acrylamide, siloxane, acrylate, or a cellulosic material and may be in the form of fibers or particles.
    Type: Grant
    Filed: November 7, 1994
    Date of Patent: June 25, 1996
    Assignee: Georgia Tech Research Corporation
    Inventors: Jan W. Gooch, Charlene W. Bayer
  • Patent number: 5503662
    Abstract: A canister including an elongated hollow plastic body having a wall with inner and outer surfaces, an edge portion on the wall defining an open end, an end on the edge portion extending transversely to the inner and outer surfaces, a porous plastic member having an outer edge portion extending across the open end and fused to the end, an inner portion on the porous plastic member located radially inwardly of the outer edge portion and extending into the body and fused to the inner surface of the wall adjacent the end thereof, and a gas-treating material in the body. A method of fabricating the above canister including the steps of applying pressure and vibratory welding energy to the porous member to thereby cause the member which was originally planar in shape to have its outer edge compressed against the end of the body and fused thereto and the central portion inwardly of the outer edge forced into the body and its outer edge fused to the inner surface of the body adjacent the end.
    Type: Grant
    Filed: March 29, 1994
    Date of Patent: April 2, 1996
    Assignee: Multiform Desiccants, Inc.
    Inventor: Lora L. Berger
  • Patent number: 5496397
    Abstract: Desiccant-coated substrates, regeneratable rotary dehumidification wheels and other devices for gas (e.g., air) treatment using those substrates, and processes for making them are disclosed. The substrates may have coatings in thicknesses of from about 2 to about 10 mils containing particles of one or more adsorbent desiccants and an organic water-based binder. The desiccant particles retain a high fraction of their original adsorption capacity because the pores of the desiccant particles contain a pore-clearing agent prior to the binder setting and the pore-clearing agent leaves the pores during the manufacturing process to prevent the binder from blocking the pores. In preferred embodiments a mixture of different desiccants is used and a particle suspending agent keeps the particles well-mixed so that the desiccant particles in the coated substrate will be as well-mixed as possible. The suspending agent may also function as the pore-clearing agent.
    Type: Grant
    Filed: December 7, 1994
    Date of Patent: March 5, 1996
    Assignee: Semco Incorporated
    Inventors: John C. Fischer, Kirk T. Mescher
  • Patent number: 5470377
    Abstract: A process is described for the separation of solutes dissolved in a gaseous solvent. The process is useful in the extraction and recovery of solutes using supercritical fluid extraction, and in the purification of impure steam. The process utilizes a sorbent to remove solute followed by an in situ regeneration of the sorbent and the recovery of the solute.
    Type: Grant
    Filed: March 8, 1993
    Date of Patent: November 28, 1995
    Inventor: David R. Whitlock
  • Patent number: 5352274
    Abstract: An air filter is provided for removing gaseous impurities from the air such as formaldehyde, acetaldehyde, acrolein, acetone and other chemical compounds. The filter utilizes a plurality of corrugated base sheets which are stacked or nestled and which have entrapped carbon dust for absorption of impurities. The corrugated structure provides very little pressure drop as the air passes through available channels and large, powerful fans are not necessary to move air therethrough.
    Type: Grant
    Filed: May 10, 1993
    Date of Patent: October 4, 1994
    Inventor: Richard L. Blakley
  • Patent number: 5334237
    Abstract: A method for predicting end-of-life of a system consumable in a fluid purification system characterized by the steps of (a) coupling a model consumable to the fluid purification system which has comparable characteristics but substantially less time capacity than the system consumable; (b) diverting a portion of an unpurified fluid which could otherwise flow into the system consumable into the model consumable; and (c) analyzing the model consumable to predict the end-of-life of the system consumable. Preferably, the time capacity of the model consumable to remove impurities from the fluid is a small fraction, e.g. 25%-50%, of the capacity of the system consumable.
    Type: Grant
    Filed: February 26, 1993
    Date of Patent: August 2, 1994
    Assignee: SAES Pure Gas, Inc.
    Inventor: D'Arcy H. Lorimer
  • Patent number: 5292360
    Abstract: Adsorbent material well adapted for the purification of gases (notably by the PSA and TSA methods) by adsorbing impurities therefrom that are more polar or polarizable than the gases to be purified, e.g., nitrogen, the oxides of carbon and hydrocarbons, comprises a matrix of a type 5A zeolite molecular sieve and a kaolinite clay binder therefor, the clay binder having a concentration of at least 75% by dry weight of kaolinite and a maximum quartz concentration of 20% by dry weight.
    Type: Grant
    Filed: May 27, 1992
    Date of Patent: March 8, 1994
    Assignee: Rhone-Poulenc Chimie
    Inventors: Bernard Pacaud, Marc Mercier
  • Patent number: 5248323
    Abstract: In a vacuum cleaner comprising a reduced velocity chamber with a high velocity air inlet, an electric motor, a rotary means driven by the motor for creating a vacuum in the chamber, an outlet for exhausting air from the chamber, which air flows in a selected path from the air inlet, through the chamber and out the air exhaust outlet and a disposable porous sheet filter layer in the chamber for removing solids particles from the air there is provided an improvement comprising a gas removing filter between the filter layer and the motor where the gas removing filter comprises an activated charcoal filter layer in the chamber, intersecting the air path and generally coterminous with the disposable filter layer.
    Type: Grant
    Filed: November 9, 1992
    Date of Patent: September 28, 1993
    Assignee: Health-Mor, Inc.
    Inventor: Philip H. Stevenson
  • Patent number: 5238899
    Abstract: Disclosed is an active carbon for deodorization, which comprises a deodorizing functional group fixed to a graphitic six-membered ring on the surface of the active carbon, through a silanol bond.
    Type: Grant
    Filed: November 15, 1991
    Date of Patent: August 24, 1993
    Assignees: Nippondenso Co., Ltd., Nippon Soken, Inc.
    Inventors: Satoru Kadowaki, Makoto Suzuki, Kunio Okamoto, Atushi Kosaka
  • Patent number: 5238658
    Abstract: An exhaust gas treatment apparatus, which comprises first and second gas adsorbing columns each having inlet and outlet pipes; and switch-over pipes connecting the first and second gas adsorbing columns being alternatively arranged in parallel to or in series with each other, the switch-over pipes having valves arranged therein.
    Type: Grant
    Filed: February 4, 1992
    Date of Patent: August 24, 1993
    Assignee: Teisan Kabushiki Kaisha
    Inventors: Takayuki Makioka, Kohei Fujimura