WO1981000306A1 - Method of estimating life of insulation for electric device using resin insulator - Google Patents
Method of estimating life of insulation for electric device using resin insulator Download PDFInfo
- Publication number
- WO1981000306A1 WO1981000306A1 PCT/JP1980/000161 JP8000161W WO8100306A1 WO 1981000306 A1 WO1981000306 A1 WO 1981000306A1 JP 8000161 W JP8000161 W JP 8000161W WO 8100306 A1 WO8100306 A1 WO 8100306A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- resin
- insulation
- electrical equipment
- monitor
- estimating
- Prior art date
Links
- 229920005989 resin Polymers 0.000 title claims abstract description 97
- 239000011347 resin Substances 0.000 title claims abstract description 97
- 238000009413 insulation Methods 0.000 title claims abstract description 61
- 239000012212 insulator Substances 0.000 title claims description 26
- 238000000034 method Methods 0.000 title claims description 18
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 37
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims abstract description 27
- 125000004430 oxygen atom Chemical group O* 0.000 claims abstract description 21
- 230000015556 catabolic process Effects 0.000 claims description 28
- 238000006731 degradation reaction Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 7
- 238000005259 measurement Methods 0.000 claims 3
- 238000012360 testing method Methods 0.000 description 18
- 230000006866 deterioration Effects 0.000 description 13
- 230000003647 oxidation Effects 0.000 description 12
- 238000007254 oxidation reaction Methods 0.000 description 12
- 229910052799 carbon Inorganic materials 0.000 description 9
- 239000011810 insulating material Substances 0.000 description 9
- 230000007423 decrease Effects 0.000 description 8
- 150000001721 carbon Chemical group 0.000 description 6
- 238000012544 monitoring process Methods 0.000 description 6
- 238000010525 oxidative degradation reaction Methods 0.000 description 6
- 229920001059 synthetic polymer Polymers 0.000 description 5
- 239000007787 solid Substances 0.000 description 4
- KKEBXNMGHUCPEZ-UHFFFAOYSA-N 4-phenyl-1-(2-sulfanylethyl)imidazolidin-2-one Chemical compound N1C(=O)N(CCS)CC1C1=CC=CC=C1 KKEBXNMGHUCPEZ-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000003822 epoxy resin Substances 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 239000007857 degradation product Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000012774 insulation material Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 229920006122 polyamide resin Polymers 0.000 description 2
- 230000008439 repair process Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 241000238631 Hexapoda Species 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 241000849798 Nita Species 0.000 description 1
- 229920000784 Nomex Polymers 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 241000124033 Salix Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 239000004763 nomex Substances 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/44—Resins; Plastics; Rubber; Leather
- G01N33/442—Resins; Plastics
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/20—Oxygen containing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/22—Hydrogen, per se
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/23—Carbon containing
Definitions
- the present invention is intended to estimate the insulation life of electrical equipment, prevent accidents due to insulation, and know when to renew the insulation structure.
- solid, liquid, and gas insulating materials are used for insulating electrical equipment.
- the most widely used solid insulating materials include inorganic insulating materials, organic synthetic polymer insulating materials, and composites thereof. If these insulating materials are used for many years, they will suffer from electrical, mechanical and thermal oxidative degradation, degrading the insulation performance of electrical equipment and eventually causing dielectric breakdown, leading to accidents. Once an accident has occurred, serious damages may occur, leading to enormous costs and time spent on repairs, etc., and a decrease in insulation performance will be detected before insulation breakdown occurs. There is a strong demand for a method for preventive maintenance.
- OMPI In the case of gaseous insulating materials, a very small amount of degradation products dissolved in water is detected by a highly sensitive gas analyzer to determine the degree of degradation.
- the inventors of the present invention have studied a method of tracking the reduction behavior of the breakdown voltage with the operation time of an electric device using a resin insulator, and as a result, the ratio of the number of hydrogen atoms to the number of carbon atoms of the resin insulator has been reduced. Changes with the operating time of the device However, the present inventors have found that the device responds well to the lowering behavior of the dielectric breakdown voltage of the device, and have completed the present invention.
- the present invention relates to a method for estimating the insulation life of an electric device using a resin insulator, comprising extracting a resin piece from the electric device and measuring a ratio of the number of hydrogen atoms to the number of carbon atoms of the extracted resin piece. Therefore, the insulation life of the above electrical equipment is estimated.
- the resin piece may be cut directly from the insulation structure of the electrical equipment, or the same or different resin insulation material as the insulation structure of the electrical equipment may be used as the resin piece for the monitor. It is also possible to attach it to the device in advance and remove the resin piece.
- the ratio of the number of oxygen atoms to the number of carbon atoms of the above resin piece may be measured.
- the insulation life of electrical equipment can be estimated.
- An object of the present invention is to provide a method for accurately estimating the insulation life of an electric device using a resin insulator.
- Another object of the present invention is to provide an electric device using a resin insulator.
- Another object of the present invention is to provide a method of detecting a decrease in insulation performance before an electrical device is broken down, and providing a method for preventing accidents and performing appropriate measures such as renewal of insulation. This is what we are trying to do.
- FIG. 1 is a characteristic diagram showing the rate of change of the dielectric breakdown voltage of the test rod with respect to the thermal oxidative degradation time
- FIG. 2 is a graph showing the number of hydrogen atoms of the resin piece for the monitor with respect to the thermal oxidative degradation time
- FIG. 3 is a characteristic diagram showing the ratio of the number of carbon atoms to the thermal oxidation deterioration time
- FIG. 3 is a characteristic diagram showing the ratio of the number of oxygen atoms to the number of carbon atoms of the resin piece for monitoring.
- Insulation degradation of electrical equipment is mainly caused by thermal oxidation degradation of resin insulation.
- the organic synthetic polymer constituting the resin insulator is mainly composed of carbon atoms (C) and hydrogen atoms (H), and contains a small amount of oxygen atoms (0) and nitrogen atoms (N). Therefore, focusing on the carbon atoms and hydrogen atoms of the main components, due to thermal oxidative deterioration, double molecules are present in the molecule.
- the present invention focuses on the above-described behavior of resin insulators, and It is intended to provide a method for estimating the degree of insulation deterioration of electrical equipment by using behavior.
- a suitable number of resin pieces as a monitor material made using the same resin insulator that forms the insulation of the electrical device to be measured are detachably started beforehand.
- the resin pieces were previously incorporated into the electrical device to be measured, and at an appropriate time interval, for example, one piece of the resin piece was taken out at an appropriate time, and the number of hydrogen atoms and the number of carbon atoms were measured by an elemental analyzer.
- the ratio (H / C :) is calculated, and by using the model having the same insulation configuration as the actual equipment, the reduction of the dielectric breakdown voltage due to the thermal degradation obtained in advance and the monitor From the relationship between the change in the ratio of the number of hydrogen atoms to the number of carbon atoms (HZC) of the resin piece for use, the degree of insulation deterioration of the device is estimated. Therefore, it was possible to detect a decrease in insulation performance before the insulation breakdown, and to prevent accidents and to take appropriate measures for insulation renewal and the like.
- the epoxy resin was injected between two glass plates and heated and cured under the same conditions as the test rod to obtain a resin plate having a thickness of mm. 1 xio from the resin plate
- test rod and the resin piece were placed in electric furnaces set at 180 ° C, 210 ° C, and 230 ° C, respectively, and were thermally oxidized and degraded.
- test bars were out Ri taken five, in cold air, at 1 KV / sec (AC), and exits Ri preparative c simultaneously motor two motor one resin piece was measured breakdown voltage, A certain amount of the pulverized material was analyzed with a CHN coder MT2 type element analyzer manufactured by Yanagimoto Seisakusho (Japan), and the weights of hydrogen and carbon atoms were measured. , water
- the atomic number of carbon was 1.008 9 and the number of hydrogen atoms and the number of carbon atoms were divided by the atomic weight of carbon 12.0119 to calculate the ratio of the number of hydrogen atoms to the number of carbon atoms (H / C).
- the breakdown voltage is standardized by the initial value.
- FIG. 1 shows the change in the rate of change of the dielectric breakdown voltage (V) of the test rod with time during thermal oxidation degradation.
- V breakdown voltage after thermal degradation / initial breakdown voltage
- FIG. 2 shows the relationship between the ratio of the number of hydrogen atoms to the number of carbon atoms (H / C) of the resin piece for monitoring and the thermal oxidation deterioration time.
- the change in the dielectric breakdown voltage of the test rod with the thermal oxidation deterioration time was determined by the number of hydrogen atoms and the number of carbon atoms of the resin piece as a monitor. It shows the same tendency as the change in the ratio (HC), indicating that the insulation deterioration of the test rod can be estimated from the ratio of the number of hydrogen atoms to the number of carbon atoms in the monitor resin strip.
- the insulation life of the test rod is defined as the time when the dielectric breakdown voltage of the test rod is reduced to half of the initial value, the test rod force S at 180 CC, 210 , C, and 230 CC
- the ratio of the number of hydrogen atoms to the number of carbon atoms (HZC) of the resin piece for the monitor at the time of reaching is about 1.05 for both, It is clear that they do not depend on Therefore, by tracking the ratio of the number of hydrogen atoms to the number of carbon atoms (H / C) of the monitor resin piece incorporated in the electrical equipment, the insulation life of the electrical equipment can be predicted. This will be.
- the method used in the present invention targets elements that are always contained in organic substances, such as carbon atoms and hydrogen atoms, and is based on changes due to thermal oxidation deterioration.
- organic substances such as carbon atoms and hydrogen atoms
- various thermosetting resins such as polyester resins, polyamide resins, polyamide resins, and thermo-softening resins, and the like.
- other organic materials can be used as the resin piece for the monitor.
- any shape such as a particle shape, a powder shape, a pellet shape, and the like can be used.
- Inorganic fillers and other additives may be mixed into the resin.
- the mounting position of the monitor resin strip is the surface of the coil in the case of a generator motor, for example, in the case of a stationary coil, and the coil in the case of a rotating coil.
- the resin piece for monitoring is attached to the electric device in advance, but the insulating property of the electric device is checked from the surface of the resin insulator constituting the insulating structure of the electric device. Even if a small amount (for example, 2) of a resin piece that does not harm is sampled, the ratio of the number of carbon atoms to the number of hydrogen atoms of the resin piece is measured, and the insulation life is estimated in the same manner as in the above example. I can't do anything. Although the amount of resin chips collected from the insulating surface of electrical equipment is very small, it is sufficient to repair it with a room-temperature-curing resin in order to make sure that the sampled parts have been collected.
- Thermal oxidative degradation of resin insulators occurs when the carbon-carbon bonds in the molecule are broken, hydrogen is released, and double bonds are formed in the molecule, and the acid is attacked by oxygen in the air and acid. It is considered that elementary atoms are fixed in the molecule and proceed. As a result, the number of hydrogen atoms per carbon atom decreases, and the number of oxygen atoms per carbon atom increases. Therefore, instead of measuring the ratio of the number of hydrogen atoms to the number of carbon atoms, the insulation life can be estimated by measuring the ratio of the number of oxygen atoms to the number of carbon atoms. Power s.
- the monitor resin pieces prepared in Example 1 were similarly placed in electric furnaces set at 180 "1, 210, and 230 C, respectively, to be thermally oxidized and degraded.
- FIG. 1 shows the change in the breakdown voltage of the test rod of Example 1 due to the thermal oxidation deterioration time.
- test specimens show that the increasing changes in Fig. 3 occur in response to the decreasing changes shown in Fig. 1.
- WA -It can be seen that it can be estimated from the ratio of resin pieces.
- the insulation life of the test rod is defined as 180 ° C, 210 ° C,
- the ratio of the number of oxygen atoms to the number of carbon atoms (0 / C) in the flakes is
- the insulation degradation characteristics and phase of the insulation structure of the electrical device under test ? ⁇ ⁇
- the relationship between the number of hydrogen atoms and the number of carbon atoms, or the ratio of the number of oxygen atoms to the number of carbon atoms, is greater than that of the resin insulator that constitutes the insulating structure with the use time of electrical equipment. If the change is much larger, the measured value will increase and decrease more greatly, and it will be a monitor resin with high sensitivity to thermal oxidation deterioration.
- Insulation deterioration of electrical equipment is mainly caused by thermal oxidation deterioration of resin insulation, which forms an insulating structure, breaking of carbon-carbon bonds in molecules, and formation of double bonds by oxidation.
- the oxygen atoms in the air attack the oxygen atoms, which are fixed in the molecule to form carbonyl groups, resulting in a decrease in the number of hydrogen atoms per carbon atom
- the number of oxygen atoms per carbon atom increases.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Testing Relating To Insulation (AREA)
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP79/96284 | 1979-07-25 | ||
JP9628479A JPS5618765A (en) | 1979-07-25 | 1979-07-25 | Insulation life estimation of electric appliance |
JP12835579A JPS5651680A (en) | 1979-10-03 | 1979-10-03 | Estimating method for insulation life of electric apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1981000306A1 true WO1981000306A1 (en) | 1981-02-05 |
Family
ID=26437508
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1980/000161 WO1981000306A1 (en) | 1979-07-25 | 1980-07-18 | Method of estimating life of insulation for electric device using resin insulator |
Country Status (5)
Country | Link |
---|---|
US (1) | US4396719A (ja) |
EP (1) | EP0036023B1 (ja) |
DE (1) | DE3049732A1 (ja) |
GB (1) | GB2067287B (ja) |
WO (1) | WO1981000306A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2516613C2 (ru) * | 2012-05-29 | 2014-05-20 | Государственное бюджетное образовательное учреждение высшего профессионального образования Нижегородский государственный инженерно-экономический институт (НГИЭИ) | Способ оценки оставшегося срока службы высоковольтной изоляции |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB888443A (en) * | 1959-07-23 | 1962-01-31 | Electr & Allied Ind Res Ass | Testing insulating materials |
US3868221A (en) * | 1973-08-31 | 1975-02-25 | Bell Telephone Labor Inc | Method and apparatus for degradation testing of stabilized polymers |
DE2652340A1 (de) * | 1976-11-17 | 1978-05-18 | Metallgesellschaft Ag | Verfahren und vorrichtung zur pruefung der thermischen stabilitaet von polyvinylchlorid |
US4149161A (en) * | 1976-12-16 | 1979-04-10 | Westinghouse Electric Corp. | Protecting electrical apparatus with gas generating compounds |
-
1980
- 1980-07-18 WO PCT/JP1980/000161 patent/WO1981000306A1/ja active IP Right Grant
- 1980-07-18 US US06/253,765 patent/US4396719A/en not_active Expired - Fee Related
- 1980-07-18 DE DE803049732A patent/DE3049732A1/de active Granted
- 1980-07-18 GB GB8108192A patent/GB2067287B/en not_active Expired
-
1981
- 1981-02-09 EP EP80901332A patent/EP0036023B1/en not_active Expired
Non-Patent Citations (2)
Title |
---|
Denki Shikensho 33 (9) (1969 - 9) P131 Table 1, P134-139. * |
See also references of EP0036023A4 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2516613C2 (ru) * | 2012-05-29 | 2014-05-20 | Государственное бюджетное образовательное учреждение высшего профессионального образования Нижегородский государственный инженерно-экономический институт (НГИЭИ) | Способ оценки оставшегося срока службы высоковольтной изоляции |
Also Published As
Publication number | Publication date |
---|---|
EP0036023B1 (en) | 1985-10-23 |
DE3049732A1 (en) | 1982-03-04 |
GB2067287B (en) | 1983-11-30 |
EP0036023A4 (en) | 1982-01-08 |
EP0036023A1 (en) | 1981-09-23 |
GB2067287A (en) | 1981-07-22 |
DE3049732C2 (ja) | 1990-06-13 |
US4396719A (en) | 1983-08-02 |
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