EP0674534A1 - Method and device for producing a hypoxic gas mixture - Google Patents
Method and device for producing a hypoxic gas mixtureInfo
- Publication number
- EP0674534A1 EP0674534A1 EP93922905A EP93922905A EP0674534A1 EP 0674534 A1 EP0674534 A1 EP 0674534A1 EP 93922905 A EP93922905 A EP 93922905A EP 93922905 A EP93922905 A EP 93922905A EP 0674534 A1 EP0674534 A1 EP 0674534A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- membrane
- gas
- fact
- gas mixture
- separation element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000203 mixture Substances 0.000 title claims abstract description 51
- 206010021143 Hypoxia Diseases 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims description 26
- 230000001146 hypoxic effect Effects 0.000 title description 8
- 239000012528 membrane Substances 0.000 claims abstract description 98
- 239000007789 gas Substances 0.000 claims abstract description 55
- 238000000926 separation method Methods 0.000 claims abstract description 33
- 239000001301 oxygen Substances 0.000 claims abstract description 26
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 26
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 24
- 230000007954 hypoxia Effects 0.000 claims abstract description 21
- -1 polysiloxane Polymers 0.000 claims abstract description 18
- 230000035699 permeability Effects 0.000 claims abstract description 7
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 5
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 5
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 5
- 229920001296 polysiloxane Polymers 0.000 claims abstract description 5
- 229920005992 thermoplastic resin Polymers 0.000 claims abstract description 5
- 229920005989 resin Polymers 0.000 claims abstract description 4
- 239000011347 resin Substances 0.000 claims abstract description 4
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 claims description 8
- 238000012856 packing Methods 0.000 claims description 8
- 239000004698 Polyethylene Substances 0.000 claims description 7
- 229920000573 polyethylene Polymers 0.000 claims description 7
- 230000029058 respiratory gaseous exchange Effects 0.000 claims description 7
- 229920000642 polymer Polymers 0.000 claims description 6
- 229920002367 Polyisobutene Polymers 0.000 claims description 5
- 230000006835 compression Effects 0.000 claims description 4
- 238000007906 compression Methods 0.000 claims description 4
- 239000004677 Nylon Substances 0.000 claims description 3
- 239000004205 dimethyl polysiloxane Substances 0.000 claims description 3
- 230000004807 localization Effects 0.000 claims description 3
- 229920001778 nylon Polymers 0.000 claims description 3
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims description 3
- 229920001083 polybutene Polymers 0.000 claims description 2
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Natural products CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 claims 1
- 238000002560 therapeutic procedure Methods 0.000 abstract 1
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 6
- 239000011521 glass Substances 0.000 description 4
- 239000012466 permeate Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920001748 polybutylene Polymers 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 229920001875 Ebonite Polymers 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 210000002816 gill Anatomy 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0057—Pumps therefor
- A61M16/0063—Compressors
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/10—Preparation of respiratory gases or vapours
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/08—Flat membrane modules
- B01D63/082—Flat membrane modules comprising a stack of flat membranes
- B01D63/0822—Plate-and-frame devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2313/00—Details relating to membrane modules or apparatus
- B01D2313/18—Specific valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2319/00—Membrane assemblies within one housing
- B01D2319/04—Elements in parallel
Definitions
- the invention concerns the methods for obtaining a gas mixture used for interrupted normobaric hypoxia and may be used in practical medicine in medical treatment with gas mixtures with a reduced oxygen content.
- the interrupted normobaric hypoxia method is based on inhalation by a patient in predetermined conditions and according to a preset method alternately of atmospheric air and a gas mixture impoverished of oxygen and containing it in the quantity of 8 to 20% by volume.
- a method and device are known for interrupted normobaric hypoxia.
- the device contains a compressor the outlet of which is connected with a gas-separation apparatus implemented on the basis of hollow polymeric fibres.
- the gas-separation apparatus is connected by means of a pipeline through a flow meter and a humidifier with a means of connection to a patient implemented as a gas chamber or gas room.
- the device contains a system for regulation of the hypoxia parameters with a means controlling the state of the patient.
- a method of obtaining a gas mixture is realized for interrupted normobaric hypoxia and of delivery of it to a patient which consists in impoverishment of atmospheric air of oxygen by means of its compression in a compressor and passing through a polymeric membrane implemented on the basis of polymeric fibres followed by delivery through a flowmeter and a humidifier to the patient (see USSR author's certificate No. 1526).
- the main disadvantage of these method and device is impossibility of automatic regulation of choice of individual patient state parameters, lack of additional filtration of gas mixture, which does not allow to have a high-quality composition of hypoxic gas mixture.
- a method of obtaining of gas mixture is also known for interrupted normobaric hypoxia including impoverishment of atmospheric air in oxygen by means of its compression in a compressor to the pressure of 2 to 10 atm, passing it through a gas-separation element containing polymeric membrane based on hollow fibre of 4-methyl pentene-1 followed by delivery of the mixture through a filter, a flowmeter, a humidifier, and a mask to the patient.
- a device for obtaining a gas mixture for interrupted normobaric hypoxia containing a shell, connections for introduction and withdrawal of the gas mixture, and, connected in series, a compressor, a gas- separation element containing polymeric membrane implemented on the basis of hollow fibres of 4-methyl pentene-1, a filter, a pipeline with a flowmeter, a humidifier, a mask with valves for breathing, an automatic system for regulation of conditions, and a means for control of the state implemented as a transmitter of oxygen in the patient's organism (see in the same place European patent No. class published ).
- the task assumed as a basis of creation of this invention is creation of a method and a device for obtaining a gas mixture for interrupted normobaric hypoxia which have a high productivity and assure the possibility of localization of gas leakage through the membrane.
- the task raised is solved by the method of obtaining a gas mixture for interrupted normobaric hypoxia including impoverishment of atmospheric air in oxygen by its compression in a compressor up to 2 to 10 atm, passing through a gas-separation element containing polymeric membrane, and subsequent delivery of the mixture through a filter, a flowmeter, a humidifier, and a mask to the patient, in which the gas-separation element consists of units of 10 to 24 flat polymeric membranes implemented of thermoplastic resin having the oxygen permeability of 0.5 to 1.5 x 10" 10 ml.cm/cm 2 .s.cm Hg in which 20 to 60% by mass of polysiloxane and hydrocarbon oil compatible with this resin at an elevated temperature are dispersed.
- a membrane which contains as thermoplastic resin a polymer chosen from the group: 4-methyl pentene- 1, polyethylene, polyisobutylene, and poly-cis-isoprene.
- a membrane which contains as polysiloxane polydimethylsiloxane.
- a membrane which contains polybutene as hydrocarbon oil.
- the task raised is also solved by the device for obtaining a gas mixture for interrupted normobaric hypoxia which contains a shell, connections for introduction and withdrawal of the gas mixture, connected in series compressor, a gas-separation element containing polymeric membrane, a filter, a pipeline with a flowmeter, a humidifier, a mask with valves for breathing, an automatic system of regulation of the conditions, and a means for control of the state implemented as an oxygen transmitter in the patient's organism, in which the gas-separation element is implemented as a packing consisting of alternately located seals as a frame and flat membrane elements in the shape of a parallelepiped clutched between two plates equipped with channels connected with pipes for introduction and withdrawal of the gas mixture, each membrane element consisting of two flat polymeric membranes located from both sides of a porous support having at one end, in the distance of 70 to 80% of its width, one recess, and these membranes are hermetically assembled around one hole inside the recess and the recesses of the consecutive membrane elements are located in
- Each two adjacent membrane elements are connected in series into a unit separated from an adjacent unit by a plate, the adjacent units being connected in parallel by the pipe for introduction of the gas mixture.
- two adjacent membrane elements are connected together with two rigid plates each of which has a hole located opposite the holes of the membrane elements.
- the membrane elements contain polymeric membranes made of a polymer chosen from the group: 4-methyl pentene-1, polyethylene, polyisobutylene, and poly-cis-isoprene.
- the invention essence consists in creation of the method and device for obtaining a gas mixture for interrupted normobaric hypoxia which allow a constant, stable composition of the hypoxic gas mixture to be assured at the oxygen content range in it of 7 to 20% vol. , a high productivity of the process being assured, about 2 to 4 times as great as that of the known method of obtaining of the gas mixture.
- the method of obtaining of the gas mixture for interrupted normobaric hypoxia is as follows: the initial air is compressed up to 2 to 10 atm in a membrane compressor and is delivered into a gas-separation element consisting of flat membranes, elements and units.
- the gas mixture leaving the gas-separation element, not passed through polymeric membrane and impoverished in oxygen passes through a filter, a gas mixture flowmeter, and a humidifier into the patient's mask for breathing with hypoxic gas mixture.
- an automatic regulation unit is built in which is connected with an oxygen content transmitter measuring the oxygen content in the patient's organism.
- the gas-separation element contains inside an enclosed housing an alternating packing of frame seals and membrane elements in the shape of a parallelepiped located and clutched between two plates equipped with channels connected with pipes for introduction and withdrawal of the gas flow.
- each membrane element consists of two polymeric flat membranes located from both sides of a porous support having at one end, in the distance of 70 to 80% of its width, at least one recess, and the two membranes are hermetically assembled around at least one hole inside this recess, and these recesses are arranged in staggered rows at consecutive membrane elements.
- the gas-separation element according this invention has preferably one or more intermediate plates which contain on each of their opposite surfaces a stretched hole the position of which corresponds to that of the holes of an adjacent membrane element, these stretched holes being connected with the outlet pipe on the side surface of the plate and these connecting pipes being located symmetrically to the plate centre.
- Branch pipes allow the connecting pipes to be connected with proper collectors.
- Two adjacent membrane elements are preferably connected with each other by intermediate plates forming membrane units which are sub-assemblies. The end and intermediate plates are identical.
- Fig. 1 shows the diagram of the apparatus for obtaining a gas mixture for normobaric hypoxia
- Fig. 2 (Fig. 2A, 2B, 2C) shows the general view of the apparatus for obtaining a gas mixture for normobaric hypoxia, with front and back covers removed
- Fig. 3 shows the general front view of the gas-separation element
- Fig. 4 shows the top view of the gas-separation element, represented on the fig. 3;
- Fig. 5 shows the vertical view of the gas-separation element
- Fig. 6 shows the top view of the frame seal
- Fig. 7 shows a partial view in the section along A-B-C-D element represented in Fig. 6;
- Fig. 8 shows a partial section of a membrane element
- Fig. 9 (Fig. 9A, 9B) shows the view and respectively a partial section along E-E of the plate (Fig. 9A).
- Fig. 10 shows a section of two sub-assemblies with the flowsheet.
- the apparatus for obtaining a gas mixture for interrupted normobaric hypoxia represented in Fig. 1 contains compressor 1, gas separation element 2, compressor with electric drive 3, filter 4, receiver 5, condensate discharge outlet connection 6, safety valve 7, compressed air supply unions 9 and 10, choke 11, regulator 8, 12 and 22, gas separation element with flat membranes 13, humidifier 14, compensator 15, respiration valve 16, respiration mask 17, gas mixture inlet connection 18, gas discharge outlet connection 19, gas analyser 20, testing pipe union 21, choke 23, niche for the humidifier 24, gills 25, regulator 26 knob 12, control and indication board 27.
- the gas-separation element represented in Fig. 2 and follows includes an enclosed space formed by rigid bed 28 and housing 29 imagined as transparent to represent comfortably.
- the bed and housing are assembled with help of fixing devices (not shown), and air-tightness is assured by seal 30).
- the bed and housing form an air-tight enclosed space.
- packing 31 Limited with two end plates 32 and 33. It is clutched between bed 28 and rigid plate 34 with help of a number of threaded rods 35 and huts 36. Its position is set by means of two interacting centering rods 37 and 38.
- Two headers 39 and 40, respectively, for introduction of the flow to be processed and for withdrawal of the flow processed are arranged from both sides of packing 31. They pass through bed 28 and are connected on the outside with respective connecting pipes 41 and 42. Header 39 is connected by branch pipe 43 with channel 44 inside plate 32, and header 40 is connected by branch pipe 45 with channel 44 inside plate 33. Channels 47 and 48 are represented in Fig. 8.
- connecting pipe 49 connects the internal part of the enclosed space with the environment and allows, in that way, the flow to be withdrawn which passed through membranes and is named "permeate".
- Packing 31 is formed (Fig. 5 and follows) by overlapping alternately frame seals
- Fig. 7 shows the relative arrangement of membrane element 51.
- Each membrane element 51 is located between two frame seals 50 and contains two membranes 56 disposed from both sides of porous support 57, usually soft, in which there is at least one recess 58 near one end. Several recesses arranged across may be made. But it is preferable to make only one recess 58, of a stretch shape, arranged in the cross direction to the support.
- the total length of the recessed zones usually covers between 60 and 70%, preferably 65%, of the support width.
- Two membranes 56 are assembled hermetically, for example, with help of sticking or hot melting together, inside each recess (this zone is represented in Fig. 6 by a dotted line 59. It is obvious that two connected membranes may be replaced by one membrane folded up. They have in zone 59 where they are assembled hermetically one or more holes 60.
- Membrane elements 51 are arranged "in knave" (alternately in opposite positions) as it is represented in Fig. 10. End plates 32 and 33 usually have the shape of a parallelepiped, and their dimensions are similar to those of membrane elements 51.
- Two diagonally opposite holes 61 and 62 allow their arrangement on centering rods 37 and 38 to be realized.
- Two side channels 44 and 46 symmetric to the plate centre are located in the plate thickness, at each its end. Each of these channels ends on the opposite surface of the plate in cross, stretched holes 62 and" 63. The position of these holes is determined in such a way that they coincide with the position of holes 60 of the membrane elements.
- Packing 31 consists of two membrane units S x and S 2 , each of which contains several membrane elements 51. Two membrane units are separated with an intermediate plate (P) identical to end plates 32 and 33.
- the membrane units S 1 and S 2 are connected with feed header 39 by branch pipes 43 located also in parallel.
- the gas-separation element 2 may be manufactured with help of the most different materials.
- the housing 29 and the bed 28 may be made of thermoplastic materials such as polyvinylchloride, polyvinylaceto- chloride, or polymethylmetacrylate.
- As a material to manufacture a porous support filter paper, thick felt, nylon are used.
- the membranes 56 are implemented of 4- methyl pentene-1, polyethylene, polyisobutylene, and poly- cis-isoprene.
- a suspension of 2000 g of polydimethylsiloxane oil with the viscosity of 10 cSt at 25°C and of 2000 g of commercial polymer of 4-methyl pentene-1 the permeability constant for oxygen of which is equal to 3.6 x 10" 9 is prepared which is then heated for 1 hour at 260 to 270°C while agitating vigorously. A transparent viscous (melted) solution is obtained which is left alone in order that air bubbles leave it and burst on its surface. Then 3200 g of dichloromethane is introduced into the mixture. The mixture obtained in such a way is distributed on the surface of a glass billet so that a 500 ⁇ m thick layer is obtained. The glass billet is left in air at the normal temperature for 7 to 15 minutes.
- the obtained membrane has the total thickness of 10 to 100 ⁇ m.
- the pore volume is about 60% to the total volume of the membrane.
- the membrane has an elevated permeability for 0 2 , N 2 , and other gases which is about 13 times as great as that of non-modified polymer.
- Example 2 (Membrane 56) A mixture is prepared of 1000 g of polydimethyl ⁇ siloxane oil with the viscosity of 5 cSt, 1000 g of commer ⁇ cial polybutylene oil with the molecular weight of 320, and 300 g of polyethylene powder with the molecular weight of 200,000 and the permeability constant for oxygen of 4 x 10 "10 ml.cm/(cm 2 .s.cm Hg). In this case, this mixture is pressed at 175°C into 25 to 125 ⁇ m thick membranes under the pressure of the plates of 70.3 kg/cm 2 .
- a membrane 56 prepared according to example 1 is located into a gas-separation element implemented according to the design in conformity with this invention.
- the gas-separation element represented in Fig. 2 contains 16 membrane elements 51 laid onto each other and connected successively inside an air-tight housing.
- Each element 51 is composed of two membranes 56 implemented according to the method of example 1, arranged from both sides of 0.12 mm thick filter paper, and sealed up thermal ⁇ ly at 140 ⁇ C inside recess.
- the total thickness of the membrane is equal to about 200 ⁇ m, and the thickness of the selective layer of the membrane is equal to 2 ⁇ m.
- the porous layer of the membrane is located opposite filter paper.
- the rectangular membranes with the dimensions of 115 x 200 mm have 4 aligned holes of 4 mm dia. in a rec tangular thermally sealed zone with the dimensions of 8 x 68 mm.
- the useful surface of each membrane is equal to 1 dm 2 . Seals (50), 1 mm thick, are manufactured of "way- 40" hard rubber.
- Example 4 An apparatus for obtaining a gas mixture for interrupted normobaric hypoxia as shown in Fig. 1)
- Initial air containing 21% vol. 0 k and 79% vol. N 2 is compressed in a membrane compressor and is delivered into a gas-separation element implemented according to example 3.
- the gas flow leaving the gas-separation element, impov ⁇ erished in oxygen, and not passed through the membrane is delivered through a regulating valve, a pipeline, a filter, a gas mixture flowmeter, and a humidifier into a patient's mask.
- the gas separation variables are automatically regulated by a built-in unit, and an oxygen transmitter measuring the oxygen content of the patient's blood allows the patient's health state to be looked after.
- the inhalation of the hypoxic gas mixture obtained in example 4, which contains 9.5 ⁇ 0.5% vol. of oxygen and 90.5 ⁇ 0.5% vol. of nitrogen is realized as follows.
- the first day the inhalation of the hypoxic mixture is carried out 5 times for 3 minutes each time with a 3-minute pause for breathing with atmospheric air.
- the total hypoxic time is 15 minutes.
- the total time is 18 minutes.
- the total time is 28 minutes.
- the total time is 32 minutes.
- the total time is 36 minutes.
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Hematology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Emergency Medicine (AREA)
- Anesthesiology (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Dispersion Chemistry (AREA)
- Pulmonology (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
A gas mixture used in normobaric hypoxia therapy is produced by oxygen depletion of atmospheric gas compressed up to 10 atm. The gas separation unit comprises a stack of flat polymeric membranes made of a thermoplastic resin having an oxygen permeability of 0.5 to 1.5 10-10 ml.cm/cm2.s.cmHg. 20 to 60 % wt. of polysiloxane and hydrocarbon oil, which are compatible with this resin at an elevated temperature, are dispersed in the resin.
Description
METHOD AND DEVICE FOR PRODUCING A HYPOXIC GAS MIXTURE
Field of Invention
The invention concerns the methods for obtaining a gas mixture used for interrupted normobaric hypoxia and may be used in practical medicine in medical treatment with gas mixtures with a reduced oxygen content.
Background of Invention
The interrupted normobaric hypoxia method is based on inhalation by a patient in predetermined conditions and according to a preset method alternately of atmospheric air and a gas mixture impoverished of oxygen and containing it in the quantity of 8 to 20% by volume.
A method and device are known for interrupted normobaric hypoxia. The device contains a compressor the outlet of which is connected with a gas-separation apparatus implemented on the basis of hollow polymeric fibres. The gas-separation apparatus is connected by means of a pipeline through a flow meter and a humidifier with a means of connection to a patient implemented as a gas chamber or gas room. Besides, the device contains a system for regulation of the hypoxia parameters with a means controlling the state of the patient.
By means of this device, a method of obtaining a gas mixture is realized for interrupted normobaric hypoxia and of delivery of it to a patient which consists in impoverishment of atmospheric air of oxygen by means of its compression in a compressor and passing through a polymeric membrane implemented on the basis of polymeric fibres followed by delivery through a flowmeter and a humidifier to the patient (see USSR author's certificate No. 1526). The main disadvantage of these method and device is impossibility of automatic regulation of choice of individual patient state parameters, lack of additional filtration of gas mixture, which does not allow to have a high-quality composition of hypoxic gas mixture. A method of obtaining of gas mixture is also known for interrupted normobaric hypoxia including impoverishment of atmospheric air in oxygen by means of its compression in a compressor to the pressure of 2 to 10 atm, passing it through a gas-separation element containing polymeric membrane based on hollow fibre of 4-methyl pentene-1
followed by delivery of the mixture through a filter, a flowmeter, a humidifier, and a mask to the patient.
A device is also known for obtaining a gas mixture for interrupted normobaric hypoxia containing a shell, connections for introduction and withdrawal of the gas mixture, and, connected in series, a compressor, a gas- separation element containing polymeric membrane implemented on the basis of hollow fibres of 4-methyl pentene-1, a filter, a pipeline with a flowmeter, a humidifier, a mask with valves for breathing, an automatic system for regulation of conditions, and a means for control of the state implemented as a transmitter of oxygen in the patient's organism (see in the same place European patent No. class published ). The main disadvantages of the above method and device are an insufficiently high productivity of the process as well as the complete air-tightness of the membrane, which does not allow the possibility of gas escape localization to be assured, which in turn hampers the effective utilization of the gas-separation element. Summary of the Invention
The task assumed as a basis of creation of this invention is creation of a method and a device for obtaining a gas mixture for interrupted normobaric hypoxia which have a high productivity and assure the possibility of localization of gas leakage through the membrane.
The task raised is solved by the method of obtaining a gas mixture for interrupted normobaric hypoxia including impoverishment of atmospheric air in oxygen by its compression in a compressor up to 2 to 10 atm, passing through a gas-separation element containing polymeric membrane, and subsequent delivery of the mixture through a filter, a flowmeter, a humidifier, and a mask to the patient, in which the gas-separation element consists of units of 10 to 24 flat polymeric membranes implemented of
thermoplastic resin having the oxygen permeability of 0.5 to 1.5 x 10"10 ml.cm/cm2.s.cm Hg in which 20 to 60% by mass of polysiloxane and hydrocarbon oil compatible with this resin at an elevated temperature are dispersed. In this case, a membrane is used which contains as thermoplastic resin a polymer chosen from the group: 4-methyl pentene- 1, polyethylene, polyisobutylene, and poly-cis-isoprene. Besides, a membrane is used which contains as polysiloxane polydimethylsiloxane. At the same time, a membrane is used which contains polybutene as hydrocarbon oil.
The task raised is also solved by the device for obtaining a gas mixture for interrupted normobaric hypoxia which contains a shell, connections for introduction and withdrawal of the gas mixture, connected in series compressor, a gas-separation element containing polymeric membrane, a filter, a pipeline with a flowmeter, a humidifier, a mask with valves for breathing, an automatic system of regulation of the conditions, and a means for control of the state implemented as an oxygen transmitter in the patient's organism, in which the gas-separation element is implemented as a packing consisting of alternately located seals as a frame and flat membrane elements in the shape of a parallelepiped clutched between two plates equipped with channels connected with pipes for introduction and withdrawal of the gas mixture, each membrane element consisting of two flat polymeric membranes located from both sides of a porous support having at one end, in the distance of 70 to 80% of its width, one recess, and these membranes are hermetically assembled around one hole inside the recess and the recesses of the consecutive membrane elements are located in staggered rows. Each two adjacent membrane elements are connected in series into a unit separated from an adjacent unit by a plate, the adjacent units being connected in parallel by the pipe for
introduction of the gas mixture. In this case two adjacent membrane elements are connected together with two rigid plates each of which has a hole located opposite the holes of the membrane elements. The membrane elements contain polymeric membranes made of a polymer chosen from the group: 4-methyl pentene-1, polyethylene, polyisobutylene, and poly-cis-isoprene.
As a porous support for polymeric membranes, filter paper, thick felt, nylon are used. The invention essence consists in creation of the method and device for obtaining a gas mixture for interrupted normobaric hypoxia which allow a constant, stable composition of the hypoxic gas mixture to be assured at the oxygen content range in it of 7 to 20% vol. , a high productivity of the process being assured, about 2 to 4 times as great as that of the known method of obtaining of the gas mixture.
The method of obtaining of the gas mixture for interrupted normobaric hypoxia is as follows: the initial air is compressed up to 2 to 10 atm in a membrane compressor and is delivered into a gas-separation element consisting of flat membranes, elements and units. The gas mixture leaving the gas-separation element, not passed through polymeric membrane and impoverished in oxygen passes through a filter, a gas mixture flowmeter, and a humidifier into the patient's mask for breathing with hypoxic gas mixture. Into the gas-separation element, an automatic regulation unit is built in which is connected with an oxygen content transmitter measuring the oxygen content in the patient's organism.
The gas-separation element according to this invention contains inside an enclosed housing an alternating packing of frame seals and membrane elements in the shape of a parallelepiped located and clutched between two plates equipped with channels connected with pipes for
introduction and withdrawal of the gas flow. In this case, each membrane element consists of two polymeric flat membranes located from both sides of a porous support having at one end, in the distance of 70 to 80% of its width, at least one recess, and the two membranes are hermetically assembled around at least one hole inside this recess, and these recesses are arranged in staggered rows at consecutive membrane elements.
Besides, the gas-separation element according this invention has preferably one or more intermediate plates which contain on each of their opposite surfaces a stretched hole the position of which corresponds to that of the holes of an adjacent membrane element, these stretched holes being connected with the outlet pipe on the side surface of the plate and these connecting pipes being located symmetrically to the plate centre. Branch pipes allow the connecting pipes to be connected with proper collectors. Two adjacent membrane elements are preferably connected with each other by intermediate plates forming membrane units which are sub-assemblies. The end and intermediate plates are identical. Brief Description of Drawings
Fig. 1 shows the diagram of the apparatus for obtaining a gas mixture for normobaric hypoxia; Fig. 2 (Fig. 2A, 2B, 2C) shows the general view of the apparatus for obtaining a gas mixture for normobaric hypoxia, with front and back covers removed; Fig. 3 shows the general front view of the gas-separation element; Fig. 4 shows the top view of the gas-separation element, represented on the fig. 3;
Fig. 5 shows the vertical view of the gas-separation element; Fig. 6 shows the top view of the frame seal;
Fig. 7 shows a partial view in the section along A-B-C-D element represented in Fig. 6;
Fig. 8 shows a partial section of a membrane element; Fig. 9 (Fig. 9A, 9B) shows the view and respectively a partial section along E-E of the plate (Fig. 9A).
Fig. 10 shows a section of two sub-assemblies with the flowsheet.
Description of Preferred Embodiments
The apparatus for obtaining a gas mixture for interrupted normobaric hypoxia represented in Fig. 1 contains compressor 1, gas separation element 2, compressor with electric drive 3, filter 4, receiver 5, condensate discharge outlet connection 6, safety valve 7, compressed air supply unions 9 and 10, choke 11, regulator 8, 12 and 22, gas separation element with flat membranes 13, humidifier 14, compensator 15, respiration valve 16, respiration mask 17, gas mixture inlet connection 18, gas discharge outlet connection 19, gas analyser 20, testing pipe union 21, choke 23, niche for the humidifier 24, gills 25, regulator 26 knob 12, control and indication board 27.
The gas-separation element represented in Fig. 2 and follows includes an enclosed space formed by rigid bed 28 and housing 29 imagined as transparent to represent comfortably. The bed and housing are assembled with help of fixing devices (not shown), and air-tightness is assured by seal 30). The bed and housing form an air-tight enclosed space.
Inside this space, there is packing 31 limited with two end plates 32 and 33. It is clutched between bed 28 and rigid plate 34 with help of a number of threaded rods 35 and huts 36. Its position is set by means of two interacting centering rods 37 and 38. Two headers 39 and 40, respectively, for introduction of the flow to be processed and for withdrawal of the flow processed are arranged from both sides of packing 31. They pass through
bed 28 and are connected on the outside with respective connecting pipes 41 and 42. Header 39 is connected by branch pipe 43 with channel 44 inside plate 32, and header 40 is connected by branch pipe 45 with channel 44 inside plate 33. Channels 47 and 48 are represented in Fig. 8. Besides, connecting pipe 49 connects the internal part of the enclosed space with the environment and allows, in that way, the flow to be withdrawn which passed through membranes and is named "permeate". Packing 31 is formed (Fig. 5 and follows) by overlapping alternately frame seals
50 and membrane elements 51. Seals 50 and membrane elements
51 are flat and have the external profile in the shape of a parallelepiped rectangular, which allows membranes to be used practically with no wastes, based on continuous bands. They have diagonally opposite notches 52 and 63 or 4 and 55 which allow their location on centering rods 37 and 38 to be exactly determined. Fig. 7 shows the relative arrangement of membrane element 51. Each membrane element 51 is located between two frame seals 50 and contains two membranes 56 disposed from both sides of porous support 57, usually soft, in which there is at least one recess 58 near one end. Several recesses arranged across may be made. But it is preferable to make only one recess 58, of a stretch shape, arranged in the cross direction to the support. The total length of the recessed zones usually covers between 60 and 70%, preferably 65%, of the support width. Two membranes 56 are assembled hermetically, for example, with help of sticking or hot melting together, inside each recess (this zone is represented in Fig. 6 by a dotted line 59. It is obvious that two connected membranes may be replaced by one membrane folded up. They have in zone 59 where they are assembled hermetically one or more holes 60. Membrane elements 51 are arranged "in knave" (alternately in opposite positions) as it is represented in Fig. 10.
End plates 32 and 33 usually have the shape of a parallelepiped, and their dimensions are similar to those of membrane elements 51. Two diagonally opposite holes 61 and 62 allow their arrangement on centering rods 37 and 38 to be realized. Two side channels 44 and 46 symmetric to the plate centre are located in the plate thickness, at each its end. Each of these channels ends on the opposite surface of the plate in cross, stretched holes 62 and" 63. The position of these holes is determined in such a way that they coincide with the position of holes 60 of the membrane elements.
Packing 31 consists of two membrane units Sx and S2, each of which contains several membrane elements 51. Two membrane units are separated with an intermediate plate (P) identical to end plates 32 and 33.
The membrane units S1 and S2 are connected with feed header 39 by branch pipes 43 located also in parallel.
Permeate leaves the packing at the periphery of the membrane elements in the direction of the arrows shown in Fig.
In such a way, the circulation of initial air may take place inside of a membrane unit, successively from one element 51 to another and in parallel between each membrane units. This assures a great flexibility in utilization and allows the membrane unit in which leakage is discovered to be localized and isolated.
The gas-separation element 2 may be manufactured with help of the most different materials. In this case, the housing 29 and the bed 28 may be made of thermoplastic materials such as polyvinylchloride, polyvinylaceto- chloride, or polymethylmetacrylate. As a material to manufacture a porous support, filter paper, thick felt, nylon are used. The membranes 56 are implemented of 4- methyl pentene-1, polyethylene, polyisobutylene, and poly- cis-isoprene.
The following examples, with no limitation of the volume of the invention protection, illustrate the results achieved in realization of the method and the device for obtaining a gas mixture for interrupted normobaric hypoxia. Example 1 (Membrane 56)
A suspension of 2000 g of polydimethylsiloxane oil with the viscosity of 10 cSt at 25°C and of 2000 g of commercial polymer of 4-methyl pentene-1 the permeability constant for oxygen of which is equal to 3.6 x 10"9 is prepared which is then heated for 1 hour at 260 to 270°C while agitating vigorously. A transparent viscous (melted) solution is obtained which is left alone in order that air bubbles leave it and burst on its surface. Then 3200 g of dichloromethane is introduced into the mixture. The mixture obtained in such a way is distributed on the surface of a glass billet so that a 500 μm thick layer is obtained. The glass billet is left in air at the normal temperature for 7 to 15 minutes. In this time, dichloromethane evaporates and formation of polymeric film on the glass surface is assured. Then the film on the glass billet is submerged in a tank with methanol at 23°C. In 5 to 7 minutes the billet is pulled out and left in air at 25°C. In 2 hours, one makes sure that the membrane has become hard and removes the billet. The obtained membrane has the total thickness of 10 to 100 μm. The pore volume is about 60% to the total volume of the membrane. The membrane has an elevated permeability for 02, N2, and other gases which is about 13 times as great as that of non-modified polymer. Example 2 (Membrane 56) A mixture is prepared of 1000 g of polydimethyl¬ siloxane oil with the viscosity of 5 cSt, 1000 g of commer¬ cial polybutylene oil with the molecular weight of 320, and 300 g of polyethylene powder with the molecular weight of 200,000 and the permeability constant for oxygen of 4 x 10"10 ml.cm/(cm2.s.cm Hg). In this case, this mixture is
pressed at 175°C into 25 to 125 μm thick membranes under the pressure of the plates of 70.3 kg/cm2. On cooling, the membranes are washed with xylene to remove polybutylene oil and then submerged in polymethylsiloxane oil with the viscosity of 10 cSt at 25βC. The finished membranes have the permeability 7 times as great as that of non-modified polyethylene. Example 3 (gas-separation element 2)
A membrane 56 prepared according to example 1 is located into a gas-separation element implemented according to the design in conformity with this invention.
The gas-separation element represented in Fig. 2 contains 16 membrane elements 51 laid onto each other and connected successively inside an air-tight housing. Each element 51 is composed of two membranes 56 implemented according to the method of example 1, arranged from both sides of 0.12 mm thick filter paper, and sealed up thermal¬ ly at 140βC inside recess. The total thickness of the membrane is equal to about 200 μm, and the thickness of the selective layer of the membrane is equal to 2 μm. The porous layer of the membrane is located opposite filter paper. The rectangular membranes with the dimensions of 115 x 200 mm have 4 aligned holes of 4 mm dia. in a rec tangular thermally sealed zone with the dimensions of 8 x 68 mm. The useful surface of each membrane is equal to 1 dm2. Seals (50), 1 mm thick, are manufactured of "way- 40" hard rubber.
The above gas-separation element covered with a polyvinylchloride housing 29 is put into an apparatus for obtaining a gas mixture for interrupted normobaric hypoxia. Example 4 (An apparatus for obtaining a gas mixture for interrupted normobaric hypoxia as shown in Fig. 1)
Initial air containing 21% vol. 0k and 79% vol. N2 is compressed in a membrane compressor and is delivered into a gas-separation element implemented according to example
3. The gas flow leaving the gas-separation element, impov¬ erished in oxygen, and not passed through the membrane is delivered through a regulating valve, a pipeline, a filter, a gas mixture flowmeter, and a humidifier into a patient's mask. The gas separation variables are automatically regulated by a built-in unit, and an oxygen transmitter measuring the oxygen content of the patient's blood allows the patient's health state to be looked after.
A series of experiments is carried out at t = 24°C, the initial air being delivered to the membrane under an elevated pressure and the gaseous permeate flow being withdrawn under the pressure of 745 mm Hg. The results obtained are indicated in the Table, the flowrates being expressed in 1/hour reduced to the normal conditions of temperature and pressure (0°C, 760 mm Hg). The abbrevi¬ ations used have the meanings as follows: A - air delivery flowrate (at 21% vol. of oxygen); B - flowrate of the gas mixture not passed through the membranes; C - oxygen content, per cent, in F;
D - permeate flowrate (gas mixture passed through the membranes); Y - oxygen content, per cent, in D.
Table
P A F X D Y (bar)
6 980 930 20.4 47 36.5
8 925 870 20.3 53 36.5
8.9 1050 1000 20.1 48 36
11 1060 1000 - 60 38
3.65 990 940 20.1 50 36.5
3.65 215 163 16.8 52 33.5
3.65 73 23 7.8 49 27.0
The utilisation of the obtained gas mixture for interrupted normobaric hypoxia is realized as follows: Example 5 (Medical treatment)
The inhalation of the hypoxic gas mixture obtained in example 4, which contains 9.5 ± 0.5% vol. of oxygen and 90.5 ± 0.5% vol. of nitrogen is realized as follows. In the first day, the inhalation of the hypoxic mixture is carried out 5 times for 3 minutes each time with a 3-minute pause for breathing with atmospheric air. The total hypoxic time is 15 minutes. In the second day, 6 times for 3 with a 2-minute pause. The total time is 18 minutes. In the third day, 7 times for 4 minutes with a 2- minute pause. The total time is 28 minutes. In the fourth day, eight times for 4 minutes with a 2-minute pause. The total time is 32 minutes. In the fifth day, 9 times for 4 minutes with a 2-minute pause. The total time is 36 minutes. In the 6th day, 9 times for 5 min. with 2-min. pause. The total time is 45 min. In the 7th day, 10 times for 5 with 2-min. pause. The total time is 50 min. In the 8th day, 11 times for 5 with 2-min. pause. The total time is 55 min. From the 9th to the 11th day 12 times for 5 with 2-min. pause. The total time is 60 min. In the 12th day,5
times for 6 with 2-min. pause. The total time is 30 min. In the 13th day, 6 times for 6 with 2-min. pause, 36 min. In the 14th day, 6 times for 8 with 2-min. pause, 48 min. In the 15th day, 7 times for 8 with 2-min. pause, 56 min. In the 16th day, 5 times for 10 with 2-min. pause, 50 min. In the 17th day, 6 times for 10 with 2-min. pause, 60 min. From the 18th to the 20th days, 6 times for 10 with 2-min. pause, 60 min. After the 20th seance, the treatment is realized depending on the patient's clinical data. After the 20th seance, 3 times a week 3 to 6 times for 10 minutes with 2-min. pause during 2 weeks. And then 2 times a week in the same conditions during 1 week. In 3 to 4 months, the complete course of treatment is repeated once more.
Claims
1. Method of producing a gas mixture for interrupted normobaric hypoxia including impoverishment of atmospheric air in oxygen by its compression in a compressor up to 2 to 10 atm, passing it through a gas-separation element containing polymeric membrane, and subsequent delivery of the mixture through a filter, a flowmeter, a humidifier, and a patient's mask, characterised by the fact that to increase the process productivity the gas-separation element consists of units of flat polymeric membranes made of a thermoplastic resin having the oxygen permeability of 0.5 to 1.5 x 10"10 ml.cm/cm2.s.cm Hg in which 20 to 60% wt. of polysiloxane and hydrocarbon oil is dispersed which are compatible with this resin at an elevated temperature.
2. Method according to claim 1, characterised by the fact that a membrane is used which contains as thermoplastic resin a polymer chosen from the group: 4- methyl pentene-1, polyethylene, polyisobutylene, and poly- cis-isoprene.
3. Method according to claims 1 and 2, characterised by the fact that a membrane is used which contains polydimethylsiloxane as a polysiloxane.
4. Method according to claims 1 to 4, characterised by the fact that a membrane is used which contains polybutene as a hydrocarbon oil.
5. Device for realization of the method according claim 1, containing a shell, connections for introduction and withdrawal of the gas mixture, connected in series compressor, a gas-separation element containing polymeric membrane, a filter, a pipeline with a flowmeter, a humidifier, a mask with valves for breathing, an automatic system of regulation of the process variables, and a means for controlling the state implemented es a transmitter of oxygen in the patient's organism, characterised by the fact that, to assure the possibility of localization of gas leakage through the membrane, the gas-separation element is implemented as a packing consisting of alternately located seals in the shape of a frame and flat membrane elements in the shape of a parallelepiped clutched between two plates equipped with channels connected with the connecting pipes for introduction and withdrawal of the gas mixture, each of the membrane elements consisting of two flat polymeric membranes arranged on both sides of a porous support having at one end, in the distance of 70 to 80% of its width, one recess, and these membranes are hermetically assembled around one hole inside the recess, and the recesses of subsequent membrane elements are arranged in staggered rows.
6. Device according claim 5, characterised by the fact that each two adjacent membrane elements are connected into a unit separated from an adjacent unit with a plate, the adjacent units being connected in parallel with the connecting pipe for introduction of the gas mixture.
7. Device according claims 5 and 6, characterised by the fact that two adjacent membrane elements are connected together with two rigid plates, each of which has a hole located opposite the holes of the membrane elements.
8. Device according to claims 5 to 7, characterised by the fact that the membrane elements contain polymeric membranes made of a polymer chosen from the group: 4- methyl pentene-1, polyethylene, polyisobutylene, poly-cis- isoprene.
9. Device according to claims 5 to 8, characterised by the fact that as a porous support for polymeric membranes filter paper, thick felt, nylon are used.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/EP1993/002568 WO1995008360A1 (en) | 1993-09-22 | 1993-09-22 | Method and device for producing a hypoxic gas mixture |
Publications (1)
Publication Number | Publication Date |
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EP0674534A1 true EP0674534A1 (en) | 1995-10-04 |
Family
ID=8165763
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP93922905A Withdrawn EP0674534A1 (en) | 1993-09-22 | 1993-09-22 | Method and device for producing a hypoxic gas mixture |
Country Status (4)
Country | Link |
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EP (1) | EP0674534A1 (en) |
JP (1) | JPH08503643A (en) |
AU (1) | AU5175693A (en) |
WO (1) | WO1995008360A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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RU2716478C1 (en) * | 2019-08-23 | 2020-03-11 | Егор Егоров | Method of producing therapeutic gas mixtures and a method for training patients with therapeutic gas mixtures |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
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EP0865796B1 (en) * | 1996-09-02 | 2007-03-07 | Tkachuk, Elena Nikanorovna | Installation for producing a gas mixture for hypoxia therapy |
US6033457A (en) * | 1998-03-23 | 2000-03-07 | Oxynet, Inc. | Oxygen generator system and method of operating the same |
US6290757B1 (en) | 1999-03-26 | 2001-09-18 | Ceramphysics, Inc. | Nitrogen purification device |
US6592731B1 (en) | 1999-09-23 | 2003-07-15 | Ceramphysics, Inc. | Amperometric oxygen sensor |
US6824661B2 (en) | 1999-09-23 | 2004-11-30 | Ceramphysics, Inc. | Combined oxygen and NOx sensor |
US7939014B2 (en) | 2005-07-11 | 2011-05-10 | Saint-Gobain Performance Plastics Corporation | Radiation resistant silicone formulations and medical devices formed of same |
US9133340B2 (en) | 2005-07-11 | 2015-09-15 | Saint-Gobain Performance Plastics Corporation | Radiation resistant silicone formulations and medical devices formed of same |
US7943697B2 (en) * | 2005-07-11 | 2011-05-17 | Saint-Gobain Performance Plastics Corporation | Radiation resistant silicone formulations and medical devices formed of same |
CN109966619B (en) * | 2019-04-24 | 2021-04-20 | 王网金 | Device for controlling oxygen output concentration |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
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BE759809A (en) * | 1969-12-04 | 1971-06-03 | Dow Chemical Co | MEMBRANES WITH IMPROVED PERMEABILITY TO GAS AND THEIR MANUFACTURING PROCESS |
US4187086A (en) * | 1977-06-15 | 1980-02-05 | General Electric Company | Packaged membrane system and replenishment method |
US4174955A (en) * | 1978-02-27 | 1979-11-20 | Oxygen Enrichment Co., Ltd. | Membrane oxygen enricher apparatus |
US4406673A (en) * | 1979-12-27 | 1983-09-27 | Teijin Limited | Ultrathin solid membrane, process for production thereof, and use thereof for concentrating a specified gas in a gaseous mixture |
DE69030623T2 (en) * | 1990-08-29 | 1997-12-18 | Tradotec Sa | Device for producing a hypoxic gas mixture |
-
1993
- 1993-09-22 JP JP7509511A patent/JPH08503643A/en active Pending
- 1993-09-22 WO PCT/EP1993/002568 patent/WO1995008360A1/en not_active Application Discontinuation
- 1993-09-22 EP EP93922905A patent/EP0674534A1/en not_active Withdrawn
- 1993-09-22 AU AU51756/93A patent/AU5175693A/en not_active Abandoned
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See references of WO9508360A1 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2716478C1 (en) * | 2019-08-23 | 2020-03-11 | Егор Егоров | Method of producing therapeutic gas mixtures and a method for training patients with therapeutic gas mixtures |
RU2716478C9 (en) * | 2019-08-23 | 2020-09-14 | Егор Егоров | Method of producing therapeutic gas mixtures and a method for training patients with therapeutic gas mixtures |
Also Published As
Publication number | Publication date |
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JPH08503643A (en) | 1996-04-23 |
WO1995008360A1 (en) | 1995-03-30 |
AU5175693A (en) | 1995-04-10 |
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