EP0192573B1 - System zum Plasmaschneiden oder Plasmaschweissen mit Zeitregler - Google Patents

System zum Plasmaschneiden oder Plasmaschweissen mit Zeitregler Download PDF

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Publication number
EP0192573B1
EP0192573B1 EP86400343A EP86400343A EP0192573B1 EP 0192573 B1 EP0192573 B1 EP 0192573B1 EP 86400343 A EP86400343 A EP 86400343A EP 86400343 A EP86400343 A EP 86400343A EP 0192573 B1 EP0192573 B1 EP 0192573B1
Authority
EP
European Patent Office
Prior art keywords
torch
cutting
flow
gas
duration
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.)
Expired
Application number
EP86400343A
Other languages
English (en)
French (fr)
Other versions
EP0192573A1 (de
Inventor
Gérard Marhic
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Lincoln Electric Co France SA
Original Assignee
La Soudure Autogene Francaise
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by La Soudure Autogene Francaise, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical La Soudure Autogene Francaise
Priority to AT86400343T priority Critical patent/ATE46804T1/de
Publication of EP0192573A1 publication Critical patent/EP0192573A1/de
Application granted granted Critical
Publication of EP0192573B1 publication Critical patent/EP0192573B1/de
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/36—Circuit arrangements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/28—Cooling arrangements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3494—Means for controlling discharge parameters

Definitions

  • the present invention relates to a plasma welding or cutting system, of the type comprising an ignition torch by cuort-circuit with fixed electrode and movable nozzle, means for supplying gas to the torch to provide it with a strong plasma gas flow rate, as well as electrical supply means for the torch to generate, maintain or cut an electric arc of plasma welding or cutting, the nozzle being mounted with axial movement until contact with the electrode against the action of an elastic return means towards a position of maximum mutual spacing corresponding to normal operation.
  • the nozzle is thus mounted to slide freely in the body of the torch, so as to come into contact with the electrode when the torch is applied against a workpiece.
  • an arc lights up between the electrode and the nozzle making it possible to initiate and maintain an electric arc between these parts, said arc being transferred to the part to be cut.
  • the plasma gas continues to be injected into the torch as long as the system is kept energized. This makes it possible in particular to cool the torch after use.
  • the system is not very economical, since plasma gas is also injected in the absence of an electric arc. In addition, it is particularly troublesome during ignition by short circuit, because it requires a large force to achieve it. If the workpiece is thin and cantilevered, ignition becomes very difficult.
  • the system according to the invention makes it possible to avoid this drawback.
  • it comprises timing means connected, on the one hand, to the electrical supply means of the torch, and on the other hand, to the gas supply means of the torch, said timing means being sensitive upon cutting off the electric arc of the torch and controlling the stopping or reduction of said gas flow after a predetermined time interval following the cutting off of the electric arc, so as to cool the torch during said interval of time.
  • said time delay means comprise means for adjusting the predetermined time interval.
  • the system according to the invention is characterized in that the gas supply means comprise in particular a first solenoid valve, the opening or closing of which controls the passage of the plasma gas, the electrical circuit for controlling said solenoid valve being connected to the power supply means via the timing means.
  • the gas supply means comprise in particular a first solenoid valve, the opening or closing of which controls the passage of the plasma gas, the electrical circuit for controlling said solenoid valve being connected to the power supply means via the timing means.
  • the nozzle which is movable in the torch body can, for example, under the effect of the weight of the torch, slide in its housing and come to inadvertently start the ignition process of the arc, without deliberate action of the operator.
  • the gas supply means include in particular a second solenoid valve with two flow rates.
  • the electrical control circuit of which is connected to the electrical supply means the first flow corresponding to the phases to generate and maintain the electric arc, the second flow, lower than the first, corresponding to the phase in which the electric arc is cut while the installation is still energized, this flow rate scond is of sufficient value to keep the nozzle and the electrode away from each other, regardless of the position of the torch.
  • the cutting of the plasma electric arc causes the passage from the normal flow to the low flow of the second solenoid valve, this low flow making it possible both to cool the electrode and the nozzle on the one hand, and to maintain the nozzle on its seat at a distance from the electrode, on the other hand.
  • this second embodiment of the invention particularly applicable in the case where the second (low) flow rate of the second solenoid valve is not sufficient to properly cool the electrode and the nozzle, it is provided that the means of time delay are inserted between the control circuit of the second solenoid valve and the electrical supply means, the gas supply means being always open when the system is energized, so as to cool the torch using of the first gas flow from the second solenoid valve, when the electric arc is cut off, then maintaining the gap between the electrode and the nozzle using the second flow of the second solenoid valve.
  • the user may wish to reactivate the torch also for the duration of the time delay, during which the gas flow is identical to the gas flow of the torch during the welding or cutting phase.
  • the force to be exerted on the torch to cause the short circuit is much greater than when starting without gas flow or at low gas level. It is then found that the lighting of the torch is very difficult, in particular on a thin plate, in overhang.
  • the invention provides, according to a preferred embodiment, two alternatives:
  • the first in which the timer has a double duration, one short (or zero) corresponding to a short use of the torch, the other long, corresponding to a longer use of the torch. These durations are determined according to the material and its use.
  • the second in which the time delay varies continuously according to the duration of use of the torch, up to a maximum threshold, whatever this duration of use.
  • this time delay will have a duration of zero when the duration of the previous cutting step is less than a predetermined value.
  • the duration of this time delay will be a function of the preceding cutting duration, without being able to exceed a maximum value defined experimentally as a function of the structure and the materials used in this torch.
  • This maximum duration is that which makes it possible to reduce the temperature of the nozzle to a value of the order of ambient temperature, for the gas flow rate used with this torch.
  • the function which defines the duration of the temperature will preferably be a function of the exponential type;
  • the corresponding electrical circuit will preferably use the charge and / or discharge of a capacitor, triggered by the start of the cutting operation, to determine the duration of the time delay.
  • the means necessary for these two alternatives are part of the means for adjusting the predetermined time interval.
  • a terminal 45 of the secondary 33 of the transformer 31 is also connected to the part 7 by a circuit incorporating in series a thermal contact 46, opening in the event of an abnormal rise in temperature, placed in the windings of the main transformer 10, a contact 47 closing under the effect of a gas pressure, placed in the gas supply pipe of the torch, an excitation winding 48, associated with an impedance 49 (capacitor 50 and resistor 51 in parallel), this winding 48 controlling, in the excited state, the closing of the contact 43, the whole being connected, by a diode 52, to the terminal 24 of the inductor 23, while the negative terminal 18 is connected, by a diode 53, to the another terminal of the secondary 33 of the transformer 31.
  • the terminal 22 of the inductor 23 is connected by a conductor 55 with resistance 56 to the terminal 45 of the secondary 33 of the transformer 31.
  • the solenoid valve V together with the gas supply pipe (and the general gas supply tap, not shown), the gas supply means G.M.
  • the arc is formed by the coming into mutual contact of the electrode 2, the nozzle 3 and the part 7.
  • the auxiliary circuit 30 supplies, from the transformer 31, the winding 48 which is excited, via safety contacts 46 and 47 and short-circuit 2-3-7, which causes contact 43 of relay 48 to close, thus energizing windings 42 and 142, causing contact 15 to close of the main transformer 10, as well as the closing of the contact 86, so that the plasma gas reaches and flows into the torch through the passages 500 and 501.
  • the spacing of the electrode 2 of the nozzle 3 forms the arc welding or cutting between electrode 2 and part 7 and thus establishes the welding or cutting current.
  • Maintaining the excitation of the winding 48 is ensured by the voltage at the terminals 22-24 of the inductor 23, which depends on the existence of the welding or cutting current, this voltage ensuring the supply of the winding 48 via the conductor 55, the resistor 56, the safety contacts 46, 47 and the unidirectional element 52.
  • the contact 43 opens, the winding 42 is also de-energized opening the contact 15.
  • the winding 142 is also de-energized causing the delayed resting of the relay 86 and the closing of the solenoid valve V 1 , the winding of which 44 is no longer powered.
  • the duration of the delay on closing V 1 varies between 5 and 15 seconds. This interval is determined experimentally according to the characteristics of the torch and its use.
  • a control circuit (lamp 60 and unidirectional element 61) optically signals the correct state of the gas supply and the non-heating of the transformer 10.
  • a lamp 62 connected in series with a unidirectional element 63 optically signals the good condition of the winding 42 and of its contact 15.
  • the lamp 62 is in series with a bimetal switch 64, so that in normal operation this lamp 62 lights up dimly and goes out during '' a stop of operation.
  • the lamp 62 will start to flash in the event that the winding 42 or the contact 15 are defective, due to the existence of a high open-circuit voltage across the terminals of the secondary 16 of the transformer 10.
  • a sound device 65 in parallel on the lamp 62.
  • FIG. 2 shows an alternative embodiment of the system of Figure 1, in which the same elements as those of Figure 1 have the same references.
  • the winding 44 in this variant is part of the auxiliary control circuit 30.
  • the CGM timing means are cons here constituted by a double flow solenoid valve V 2 controlled by the winding 84, connected in series with a timed switch 85.
  • the ends of the winding 84 and the timed switch 85, not connected to each other, are connected in parallel on the winding 44 and across the secondary of the transformer 31.
  • the first flow of the solenoid valve V 2 corresponds to the normal flow of the device, this flow being at least equal to the flow of the solenoid valve V 1 .
  • the second flow rate of the solenoid valve V 2 is low, compared to the first and makes it possible to generate a calibrated gas leak.
  • This calibrated gas leak has a sufficient value to allow the nozzle and the electrode to be kept at a distance, that is to say to keep the movable nozzle resting on its seat in the torch body 1.
  • the value of this second flow is determined experimentally and the valve V 2 is chosen or adjusted so as to obtain said flow in its second position.
  • the second flow (calibrated leak) will be such that it cannot allow both the creation and maintenance of a plasma arc as well as sufficient cooling of the torch.
  • the start-up of the cutting circuit is identical to that described in FIG. 2.
  • the contact 85 closes, which generates a “high flow rate” of gas during the cutting period.
  • time t o the voltage on the negative input of the comparator amplifier A1 being greater than that on the positive input, the transistor T1 is blocked and the winding 242 is not energized.
  • Switch 185 is open.
  • the contact 85 also opens, which results in a de-excitation of the winding 84, the valve V2 immediately passing into the "low flow” position.
  • a “high flow” of gas is thus maintained in the valve V 2 and in the nozzle after the end of the cutting step, the duration of this “high flow” being equal to the value of the timeout of the timed switch 385. As previously, this value does not generally exceed a few seconds.
  • variable time delay is to provide a cooling time which is directly a function of the temperature of the torch after the previous cutting operation. For that. it is possible to record experimentally the heating curve of the torch (at a determined point thereof, for example near the electrode) as a function of the cutting time and to reproduce substantially the same curve for the variable time delay.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Plasma Technology (AREA)
  • Arc Welding In General (AREA)
  • Arc Welding Control (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)

Claims (9)

1. System zum Plasmaschweissen oder Plasmatrennen, bestehend insbesondere aus einem Brenner mit mindestens einer Elektrode (2) und einer Düse (3), einer Einrichtung zur Gasversorgung (G.M.) des Brenners, um diesem Plasmidgas zuzuführen, sowie einer Einrichtung zur Stromversorgung (E.C.M.) des Brenners, um einen Lichtbogen zum Plasmaschweissen oder Plasmatrennen zu erzeugen, aufrechtzuerhalten oder zu unterbrechen, dadurch gekennzeichnet, dass die Elektrode (2) und die Düse (3) axial bewegbar bis zur gegenseitigen Berührung gegen die Wirkung eines elastischen Rückführmittels in Richtung auf einen grössten Abstand voneinander angeordnet sind, der dem Normalbetrieb entspricht, und dass eine Verzögerungseinrichtung (C.G.M.) vorgesehen ist, die einerseits mit der Einrichtung zur Stromversorgung (E.C.M.) des Brenners und andererseits mit der Einrichtung zur Gasversorgung (G.M.) des Brenners verbunden ist, und dass die Verzögerungseinrichtung auf die Unterbrechung des Lichtbogens des Brenners anspricht und das Schliessen der Einrichtung zur Gasversorgung (G.M.) des Brenners nach Ablauf einer vorbestimmten Zeitspanne nach der Unterbrechung des Lichtbogens bewirkt, so dass die Kühlung des Brenners während dieser Zeitspanne aufrechterhalten bleibt.
2. System zum Plasmaschweissen oder Plasmatrennen, nach Anspruch 1, dadurch gekennzeichnet, dass die genannte Verzögerungseinrichtung (C.G.M.) eine Einrichtung zum Einstellen der vorbestimmten Zeitspanne aufweist.
3. System nach Anspruch 2, dadurch gekennzeichnet, dass die Einrichtung zum Einstellen der vorbestimmten Zeitspanne so ausgebildet ist, dass die Verzögerung von der Dauer des vorangegangenen Trennvorgangs abhängt.
4. System zum Plasmaschweissen oder Plasmatrennen nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass die Einrichtung zur Gasversorgung (G.M.) insbesondere ein erstes Elektroventil (Vi) aufweist, dessen Schliessen oder Öffnen den Durchstrom des Plasmidgases steuert, und dass der Steuerstromkreis (44) des genannten Elektroventils (V1) über die Verzögerungseinrichtung (C.G.M.) mit der Stromversorgungseinrichtung (E.C.M.) verbunden ist.
5. System zum Plasmaschweissen oder Plasmatrennen, nach einem der Ansprüche 1 bis 4, in welchem das Mittel zur elastischen Rückführung durch den Durchsatz von Plasmidgas in der Düse gebildet wird, dadurch gekennzeichnet, dass die Gasversorgungseinrichtung (G.M.) insbesondere ein zweites Elektroventil (V2) mit zwei Durchflussleistungen aufweist, dessen Steuerstromkreis (84) mit der Stromversorgungseinrichtung (E.C.M.) verbunden ist, wobei die erste Durchflussleistung den Phasen zum Erzeugen und Aufrechterhalten des Lichtbogens entspricht und die zweite, gegenüber der ersten Durchflussleistung niedrigere Durchflussleistung der Phase entspricht, in der der Lichtbogen unterbrochen ist, während das System weiterhin unter Spannung steht, und wobei die zweite Durchflussleistung einen so grossen Wert hat, dass die Düse (3) und die Elektrode (2) unabhängig von der Stellung des Brenners (1 ) Abstand voneinander behalten.
6. System nach einem der Ansprüche 2 bis 5, dadurch gekennzeichnet, dass die Einrichtung zum Einstellen der vorbestimmten Zeitspanne eine Einrichtung zum Messen der Dauer des Trennvorgangs, eine Einrichtung zum Vergleichen dieser Dauer mit einer vorbestimmten Dauer und eine Einrichtung aufweist, die die Trenngasversorgung mit hoher Durchsatzleistung unterbricht, sobald der Trennvorgang beendet ist, sofern die Dauer des Trennvorgangs geringer ist als die genannte vorbstimmte Dauer.
7. System nach Anspruch 6, dadurch gekennzeichnet, dass die Einrichtung zum Einstellen der vorbestimmten Zeitspanne ausserdem eine Einrichtung aufweist, die die Gasversorgung mit hoher Durchsatzleistung nach Ablauf einer vorbestimmten Zeitspanne nach Beendigung des Trennvorgangs unterbricht, wenn die Dauer des vorangegangenen Trennvorgangs grösser als die oder gleich der genannten vorbestimmten Dauer ist.
8. System nach Anspruch 6, dadurch gekennzeichnet, dass die Einrichtung zum Einstellen der vorbestimmten Zeitspanne ausserdem eine Einrichtung aufweist, die die Gasversorgung mit hohem Leistungsdurchsatz bei Beendigung des Trennvorgangs nach Ablauf einer Zeitspanne unterbricht, die von der Dauer dieses Vorgangs abhängt.
9. System nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass die Verzögerungsdauer von der Temperatur des Brenners am Ende des Trennvorgangs abhängt.
EP86400343A 1985-02-22 1986-02-19 System zum Plasmaschneiden oder Plasmaschweissen mit Zeitregler Expired EP0192573B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86400343T ATE46804T1 (de) 1985-02-22 1986-02-19 System zum plasmaschneiden oder plasmaschweissen mit zeitregler.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8502554 1985-02-22
FR8502554A FR2578138B1 (fr) 1985-02-22 1985-02-22 Systeme de soudage ou de coupage plasma muni d'une temporisation

Publications (2)

Publication Number Publication Date
EP0192573A1 EP0192573A1 (de) 1986-08-27
EP0192573B1 true EP0192573B1 (de) 1989-09-27

Family

ID=9316525

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86400343A Expired EP0192573B1 (de) 1985-02-22 1986-02-19 System zum Plasmaschneiden oder Plasmaschweissen mit Zeitregler

Country Status (14)

Country Link
US (1) US4692582A (de)
EP (1) EP0192573B1 (de)
JP (1) JPS61222678A (de)
AR (1) AR240119A1 (de)
AT (1) ATE46804T1 (de)
AU (1) AU577673B2 (de)
BR (1) BR8600731A (de)
CA (1) CA1253578A (de)
DE (1) DE3665970D1 (de)
DK (1) DK169455B1 (de)
ES (1) ES8705181A1 (de)
FR (1) FR2578138B1 (de)
PT (1) PT82065B (de)
ZA (1) ZA861214B (de)

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US5070227A (en) * 1990-04-24 1991-12-03 Hypertherm, Inc. Proceses and apparatus for reducing electrode wear in a plasma arc torch
US5166494A (en) * 1990-04-24 1992-11-24 Hypertherm, Inc. Process and apparatus for reducing electrode wear in a plasma arc torch
US5695662A (en) * 1988-06-07 1997-12-09 Hypertherm, Inc. Plasma arc cutting process and apparatus using an oxygen-rich gas shield
US5396043A (en) * 1988-06-07 1995-03-07 Hypertherm, Inc. Plasma arc cutting process and apparatus using an oxygen-rich gas shield
DE3840459A1 (de) * 1988-11-14 1990-05-17 Merkle Wilhelm Schweissmasch Schneidbrenner
IT1225341B (it) * 1988-11-15 1990-11-13 Cebora Spa Circuito di protezione per una apparecchiatura di saldatura o taglio al plasma con arco non trasferito o trasferito
US4973816A (en) * 1989-03-28 1990-11-27 Delaware Capital Formation, Inc. Plasma torch with safety switch
US4996407A (en) * 1989-04-03 1991-02-26 Hyperpower, Inc. Plasma arc transfer controller
US5216221A (en) * 1992-01-17 1993-06-01 Esab Welding Products, Inc. Plasma arc torch power disabling mechanism
US5416297A (en) * 1993-03-30 1995-05-16 Hypertherm, Inc. Plasma arc torch ignition circuit and method
US5620617A (en) * 1995-10-30 1997-04-15 Hypertherm, Inc. Circuitry and method for maintaining a plasma arc during operation of a plasma arc torch system
US5961855A (en) * 1998-01-28 1999-10-05 Thermal Dynamics Corporation Low voltage electrical based parts-in-place (PIP) system for contact start torch
US6163009A (en) * 1998-10-23 2000-12-19 Innerlogic, Inc. Process for operating a plasma arc torch
US6326583B1 (en) 2000-03-31 2001-12-04 Innerlogic, Inc. Gas control system for a plasma arc torch
US6677551B2 (en) * 1998-10-23 2004-01-13 Innerlogic, Inc. Process for operating a plasma arc torch
US6498317B2 (en) 1998-10-23 2002-12-24 Innerlogic, Inc. Process for operating a plasma arc torch
DE29911974U1 (de) * 1999-07-09 2000-11-23 Agrodyn Hochspannungstechnik GmbH, 33803 Steinhagen Plasmadüse
US6350960B1 (en) 2000-11-28 2002-02-26 Thermal Dynamics Corporation Parts-in-place safety reset circuit and method for contact start plasma-arc torch
US7807937B2 (en) * 2005-01-03 2010-10-05 Illinois Tool Works Inc. Method and system of conserving plasma torch consumable
US20080055795A1 (en) * 2006-08-25 2008-03-06 Miller Theodore J Power supply start-up circuit for a trip unit and circuit interrupter including the same
US8258423B2 (en) 2009-08-10 2012-09-04 The Esab Group, Inc. Retract start plasma torch with reversible coolant flow
US9949356B2 (en) 2012-07-11 2018-04-17 Lincoln Global, Inc. Electrode for a plasma arc cutting torch
WO2018022547A1 (en) * 2016-07-29 2018-02-01 Illinois Tool Works Inc. Automated plasma cutting apparatus with a housing comprising a movable plasma nozzle, and plasma cutting system
WO2020044422A1 (ja) * 2018-08-28 2020-03-05 株式会社Ｆｕｊｉ プラズマ発生装置とプラズマヘッド冷却方法

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JPS5768270A (en) * 1980-10-17 1982-04-26 Hitachi Ltd Control method for plasma cutting
FR2562453B1 (fr) * 1984-04-04 1988-02-26 Soudure Autogene Francaise Equipement de coupage plasma de tres faible puissance
US4580032A (en) * 1984-12-27 1986-04-01 Union Carbide Corporation Plasma torch safety device

Also Published As

Publication number Publication date
AU5378386A (en) 1986-08-28
US4692582A (en) 1987-09-08
ZA861214B (en) 1986-10-29
BR8600731A (pt) 1986-11-04
FR2578138A1 (fr) 1986-08-29
AU577673B2 (en) 1988-09-29
EP0192573A1 (de) 1986-08-27
ATE46804T1 (de) 1989-10-15
JPH029917B2 (de) 1990-03-05
ES552069A0 (es) 1987-04-16
AR240119A1 (es) 1990-01-31
DK169455B1 (da) 1994-10-31
PT82065A (fr) 1986-03-01
FR2578138B1 (fr) 1987-03-27
JPS61222678A (ja) 1986-10-03
DK78386D0 (da) 1986-02-20
PT82065B (pt) 1992-05-29
ES8705181A1 (es) 1987-04-16
DK78386A (da) 1986-08-23
DE3665970D1 (en) 1989-11-02
CA1253578A (fr) 1989-05-02

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