EP0366522B1 - Magnetic mine-sweeping system - Google Patents
Magnetic mine-sweeping system Download PDFInfo
- Publication number
- EP0366522B1 EP0366522B1 EP19890402863 EP89402863A EP0366522B1 EP 0366522 B1 EP0366522 B1 EP 0366522B1 EP 19890402863 EP19890402863 EP 19890402863 EP 89402863 A EP89402863 A EP 89402863A EP 0366522 B1 EP0366522 B1 EP 0366522B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- solenoids
- magnetic
- magnetic field
- solenoid
- flat coils
- 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 - Lifetime
Links
- 230000005291 magnetic effect Effects 0.000 title claims description 25
- 238000010408 sweeping Methods 0.000 title claims 2
- 238000004088 simulation Methods 0.000 claims description 3
- 241001417527 Pempheridae Species 0.000 claims 1
- 230000010363 phase shift Effects 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000002730 additional effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63G—OFFENSIVE OR DEFENSIVE ARRANGEMENTS ON VESSELS; MINE-LAYING; MINE-SWEEPING; SUBMARINES; AIRCRAFT CARRIERS
- B63G7/00—Mine-sweeping; Vessels characterised thereby
- B63G7/02—Mine-sweeping means, Means for destroying mines
- B63G7/06—Mine-sweeping means, Means for destroying mines of electromagnetic type
Definitions
- the present invention relates to magnetic dredging systems which make it possible to destroy underwater mines, the triggering of which is activated by variations in the magnetic field due to the vessel to sink.
- Most of the boats are in fact made of iron and also have large ferro-magnetic masses, and even if we have succeeded in demagnetizing them they bring a significant disturbance to the earth's magnetic field. It is then relatively easy to detect these disturbances to detonate a mine.
- this method requires bulky equipment that is difficult to tow, in order to reopen a relatively small area.
- the length distribution of the magnetic field must. correspond to that of a building of the current type, it is advantageous that the distribution in width is the greatest possible, since the mine locates the distribution of the magnetic field only along the supposed path of the building and not according to this width, which is known as an intercept. This intercept must be as wide as possible so that each passage of the dredger destroys the mines in a channel itself as wide as possible.
- each magnet is contained in a container with a diameter of 0.90m x 5m long, weighing 3 tonnes, which however allows only a moment relatively low magnetic strength of 90,000 A / m2.
- the variations of the magnetization are done in increments of 10,000 A / m2 which allows only a fairly rough approximation of the distribution of the field to be imitated.
- the distance between the dredger and the drums is approximately 400m in order to avoid any confusion between the residual magnetic field of the dredger and that of the solenoids and to prevent the dredger from being hit by the explosion of the mines when they are trigger under the action of solenoids.
- the cans are kept apart from each other by a transverse bar which keeps them separated by a width 1, corresponding to the intercept of each of the cans.
- An intercept equal to 3 1 is thus obtained, which in proportion to the mass of the solenoid and to the intensity consumed in it is considerably greater than that which would be obtained by a single solenoid.
- a solenoid was made comprising 3,960 turns whose outside diameter is 0, 90m and the total length of 4, 38m.
- the resistance of this solenoid is 5.70 ohms and its inductance of 4.5 H.
- the use of aluminum has made it possible to obtain for this device a weight less than 1.700 kg, which corresponds to a gain in mass related to copper for the same magnetic moment in a ratio of 1.77.
- the total dredging intercept 31 is therefore at least equal to 300m.
- N solenoid in parallel makes it possible, from an energy point of view, to obtain a reduction in power in a ratio of 1 / N2, that is to say in the example described in a ratio 9.
- the size and mass of the N solenoids are in total much smaller than the size and mass of a single solenoid with the same intercept. Indeed taking into account additional effects, calculations and tests carried out with a view to using a single solenoid have shown that it would be necessary to build a bulky device, very heavy and consuming about 1 megawatt of energy to obtain the same result as 'with the three solenoids described above.
- Such a device also makes it possible to simulate the alternating magnetic fields which exist on all buildings, whatever the precautions taken. Indeed for example the simple movement of the propellers in sea water, which is conductive, induces alternating magnetic fields having frequencies of the order of Hertz which, although weak, are perfectly detectable as characteristics of a building for order the firing of a magnetic mine to detect such fields.
- the device thus described makes it possible to wind next to the main solenoid a secondary solenoid intended to be supplied with alternating current to simulate these alternating magnetic fields.
- a solenoid can be produced, for example, from a wire of 2 mm2 of section wound on 158 turns over a diameter of 0, 90m and over a length of 0.35m.
- the resistance of such a solenoid is 3 ohms and its inductance of 0.09 H.
- By supplying it with an alternating current of 10 A we obtains a magnetic moment substantially equal to 1,000 A / m2, which is of an intensity quite sufficient to simulate the alternating fields of a building of suitable size.
- the figure of 1,700 kg cited above includes the weight of this solenoid intended to produce an alternating field.
- the magnetic signature of a boat or submarine is slowly variable over time and has zero crossings.
- the solenoids of the system described above are therefore supplied by alternating currents of very low frequency, of the order of 1/10 of Hertz, which should not be confused with the currents intended to simulate the parasitic alternating fields induced by example by the propellers as also described above.
- the invention provides a system according to claim 1.
- Each can 103 towed by the dredger is equipped, in addition to a known longitudinal solenoid 201, with a horizontal flat coil 221.
- the two coils are supplied by the same current I (t) coming from a generator 204 via 2 amplifiers 205 and 215.
- a 222 phase shifter ⁇ 2 is inserted between generator 204 and amplifier 215.
- the two coils thus supplied deliver a field rotating in a vertical plane parallel to the axis of movement of the container and of the tractor building.
- the number of turns is adapted so that the field components are equal in order to obtain a constant modulus of the field produced, which is therefore circular.
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Geophysics And Detection Of Objects (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Description
La présente invention se rapporte aux systèmes de dragage magnétique qui permettent de détruire les mines sous-marines dont le déclenchement est activé par les variations du champ magnétique dues au bateau à couler. La plupart des bateaux sont en effet construits en fer et comportent en outre de grosses masses ferro-magnétiques, et même si on a réussi à les démagnétiser ils apportent une perturbation importante au champ magnétique terrestre. Il est alors relativement facile de détecter ces perturbations pour faire exploser une mine.The present invention relates to magnetic dredging systems which make it possible to destroy underwater mines, the triggering of which is activated by variations in the magnetic field due to the vessel to sink. Most of the boats are in fact made of iron and also have large ferro-magnetic masses, and even if we have succeeded in demagnetizing them they bring a significant disturbance to the earth's magnetic field. It is then relatively easy to detect these disturbances to detonate a mine.
Pour draguer de telles mines, c'est-à-dire pour les faire exploser sans que cela produise des dégâts, il est connu de la demande de brevet européen 0 130 767 de remorquer derrière un dragueur de mines, lui-même particullèrement étudié pour apporter un minimum de perturbation magnétique, un ensemble d'aimants accrochés à un filin. On peut faire varier l'aimantation de ces aimants selon une suite d'incréments, ce qui permet d'imiter relativement grossièrement la répartition spatiale le long de ce dispositif du champ d'un bâtiment de grande dimension, cette répartition étant connue sous le nom de signature magnétique.To dredge such mines, that is to say to detonate them without causing damage, it is known from European patent application 0 130 767 to tow behind a minesweeper, itself particularly studied for bring a minimum of magnetic disturbance, a set of magnets hanging on a rope. The magnetization of these magnets can be varied according to a series of increments, which makes it possible to relatively roughly imitate the spatial distribution along this device of the field of a large building, this distribution being known by the name magnetic signature.
Outre le fait que la simulation est loin d'être parfaite, cette méthode nécessite un matériel volumineux et difficilement remorquable, pour rouvrir en définitive une surface relativement faible. En effet si la répartition en longueur du champ magnétique doit. correspondre à celle d'un bâtiment de type courant, il y a intérêt à ce que la répartition en largeur soit la plus grande possible, puisque la mine ne repère la répartition du champ magnétique que le long du trajet supposé du bâtiment et non pas selon cette largeur, qui est connue sous le nom d'intercept. Cet intercept doit être le plus large possible afin que chaque passage du dragueur détruise les mines dans un chenal lui-même le plus large possible.In addition to the fact that the simulation is far from perfect, this method requires bulky equipment that is difficult to tow, in order to reopen a relatively small area. Indeed if the length distribution of the magnetic field must. correspond to that of a building of the current type, it is advantageous that the distribution in width is the greatest possible, since the mine locates the distribution of the magnetic field only along the supposed path of the building and not according to this width, which is known as an intercept. This intercept must be as wide as possible so that each passage of the dredger destroys the mines in a channel itself as wide as possible.
Dans l'exemple décrit dans la demande de brevet citée en référence, chaque aimant est contenu dans un bidon d'un diamètre de 0,90m x 5m de long, pesant 3 tonnes, ce qui ne permet toutefois d'obtenir qu'un moment magnétique relativement faible de 90.000 A/m². Par ailleurs les variations de l'aimantation se font par incréments de 10.000 A/m² ce qui ne permet qu'une approximation assez grossière de la répartion du champ à imiter.In the example described in the patent application cited in reference, each magnet is contained in a container with a diameter of 0.90m x 5m long, weighing 3 tonnes, which however allows only a moment relatively low magnetic strength of 90,000 A / m². In addition, the variations of the magnetization are done in increments of 10,000 A / m² which allows only a fairly rough approximation of the distribution of the field to be imitated.
Pour pallier cet inconvénient, on a proposé dans la demande de brevet européen 0 366 522 d'utiliser un ensemble de solénoïdes répartis en largeur sur l'intercept désiré et remorqués par le dragueur de mines à bonne distance. Ces solénoïdes sont contenus dans des récipients appelés bidons et sont alimentés par un courant électrique variable, de manière à ce que les variations du champ magnétique obtenues par ces variations de courant simulent le passage d'un navire de la taille désirée, alors que la répartition des solénoïdes dans le sens d'avancement du dragueur est pratiquement ponctuelle. La distance entre le dragueur et les bidons est d'environ 400m afin d'éviter toute confusion entre le champ magnétique résiduel du dragueur et celui des solénoïdes et d'empêcher le dragueur d'être atteint par l'explosion des mines lorsqu'elles se déclenchent sous l'action des solénoïdes.To overcome this drawback, it has been proposed in European patent application 0 366 522 to use a set of solenoids distributed in width over the desired intercept and towed by the minesweeper at a good distance. These solenoids are contained in receptacles called canisters and are supplied by a variable electric current, so that the variations of the magnetic field obtained by these variations of current simulate the passage of a vessel of the desired size, while the distribution solenoids in the direction of advance of the dredger is practically punctual. The distance between the dredger and the drums is approximately 400m in order to avoid any confusion between the residual magnetic field of the dredger and that of the solenoids and to prevent the dredger from being hit by the explosion of the mines when they are trigger under the action of solenoids.
Les bidons sont maintenus écartés les uns des autres par une barre transversale qui les maintient séparés d'une largeur 1, correspondant à l'intercept de chacun des bidons. On obtient ainsi un intercept égal à 3 1, qui proportionnellement à la masse du solénoïde et à l'intensité consommée dans celui-ci est considérablement supérieur à celui qui serait obtenu par un solénoïde unique.The cans are kept apart from each other by a transverse bar which keeps them separated by a width 1, corresponding to the intercept of each of the cans. An intercept equal to 3 1 is thus obtained, which in proportion to the mass of the solenoid and to the intensity consumed in it is considerably greater than that which would be obtained by a single solenoid.
En utilisant un conducteur d'aluminium d'une section de 5 x 10mm², on a réalisé un solénoïde comportant 3.960 tours dont le diamètre extérieur est de 0, 90m et la longueur totale de 4, 38m. La résistance de ce solénoïde est de 5,70 ohms et son inductance de 4,5 H. L'utilisation de l'aluminium a permis d'obtenir pour ce dispositif un poids inférieur à 1.700 kg, ce qui correspond à un gain de masse par rapport au cuivre pour un même moment magnétique dans un rapport de 1, 77.Using an aluminum conductor with a section of 5 x 10mm², a solenoid was made comprising 3,960 turns whose outside diameter is 0, 90m and the total length of 4, 38m. The resistance of this solenoid is 5.70 ohms and its inductance of 4.5 H. The use of aluminum has made it possible to obtain for this device a weight less than 1.700 kg, which corresponds to a gain in mass related to copper for the same magnetic moment in a ratio of 1.77.
En alimentant ce solénoïde avec un amplificateur de 40 kW débitant 80 A/500V, on obtient un moment magnétique de 167.000 A/m² qui permet d'obtenir pour un seul solénoïde un intercept 1 supérieur à 100m. Dans l'exemple cite iciBy supplying this solenoid with a 40 kW amplifier delivering 80 A / 500V, we obtain a magnetic moment of 167,000 A / m² which makes it possible to obtain for a single solenoid an intercept 1 greater than 100m. In the example cited here
l'intercept total de dragage 31 est donc au moins égal à 300m. L'utilisation de N solénoïde en parallèle permet, au point de vue énergétique, d'obtenir une diminution de puissance dans un rapport de 1/N², c'est-à-dire dans l'exemple décrit dans un rapport 9. De même la taille et la masse des N solénoïdes sont au total bien plus réduites que la taille et la masse d'un solénoïde unique ayant le même intercept. En effet compte tenu d'effets annexes, des calculs et des essais menés en vue d'utiliser un solénoïde unique ont montré qu'il faudrait construire un dispositif volumineux, très pesant et consommant environ 1 Mégawatt d'énergie pour obtenir le même résultat qu'avec les trois solénoïdes décrits ci-dessus.the total dredging intercept 31 is therefore at least equal to 300m. The use of N solenoid in parallel makes it possible, from an energy point of view, to obtain a reduction in power in a ratio of 1 / N², that is to say in the example described in a ratio 9. Similarly the size and mass of the N solenoids are in total much smaller than the size and mass of a single solenoid with the same intercept. Indeed taking into account additional effects, calculations and tests carried out with a view to using a single solenoid have shown that it would be necessary to build a bulky device, very heavy and consuming about 1 megawatt of energy to obtain the same result as 'with the three solenoids described above.
Un tel dispositif permet en outre de simuler les champs magnétiques alternatifs qui existent sur tous les bâtiments, quelles que soient les précautions prises. En effet par exemple le simple mouvement des hélices dans l'eau de mer, qui est conductrice, induit des champs magnétiques alternatifs ayant des fréquences de l'ordre du Hertz qui, bien que faibles, sont parfaitement détectables comme caractéristiques d'un bâtiment pour commander la mise à feu d'une mine magnétique permettant de détecter de tels champs.Such a device also makes it possible to simulate the alternating magnetic fields which exist on all buildings, whatever the precautions taken. Indeed for example the simple movement of the propellers in sea water, which is conductive, induces alternating magnetic fields having frequencies of the order of Hertz which, although weak, are perfectly detectable as characteristics of a building for order the firing of a magnetic mine to detect such fields.
Le dispositif ainsi décrit permet de bobiner à côté du solénoïde principal un solénoïde secondaire destiné à être alimenté en courant alternatif pour simuler ces champs magnétiques alternatifs. Un tel solénoïde peut être réalisé par exemple à partir d'un fil de 2mm² de section bobiné selon 158 tours sur un diamètre de 0, 90m et sur rune longueur de 0,35m. La résistance d'un tel solénoïde est de 3 ohms et son inductance de 0,09 H. En l'alimentant avec un courant alternatif de 10 A on obtient un moment magnétique sensiblement égal à 1.000 A/m², qui est d'une intensité tout à fait suffisante pour permettre de simuler les champs alternatifs d'un bâtiment de taille convenable. Le chiffre de 1. 700 kg cité plus haut comprend le poids de ce solénoïde destiné à produire un champ alternatif. Toutefois la signature magnétique d'un bateau ou d'un sous-marin est lentement variable avec le temps et possède des passages à zéro. Les solénoïdes du système décrit ci-dessus sont donc alimentés par des courants alternatifs de fréquence très faible, de l'ordre de 1/10 de Hertz, qu'il ne faut pas confondre avec les courants destinés à simuler les champs alternatifs parasites induits par exemple par les hélices comme décrit aussi plus haut.The device thus described makes it possible to wind next to the main solenoid a secondary solenoid intended to be supplied with alternating current to simulate these alternating magnetic fields. Such a solenoid can be produced, for example, from a wire of 2 mm² of section wound on 158 turns over a diameter of 0, 90m and over a length of 0.35m. The resistance of such a solenoid is 3 ohms and its inductance of 0.09 H. By supplying it with an alternating current of 10 A we obtains a magnetic moment substantially equal to 1,000 A / m², which is of an intensity quite sufficient to simulate the alternating fields of a building of suitable size. The figure of 1,700 kg cited above includes the weight of this solenoid intended to produce an alternating field. However, the magnetic signature of a boat or submarine is slowly variable over time and has zero crossings. The solenoids of the system described above are therefore supplied by alternating currents of very low frequency, of the order of 1/10 of Hertz, which should not be confused with the currents intended to simulate the parasitic alternating fields induced by example by the propellers as also described above.
Lorsque le courant fourni par le générateur aux solénoïdes passe par zéro, toutes les composantes du champ magnétique s'annulent.When the current supplied by the generator to the solenoids goes through zero, all the components of the magnetic field cancel each other out.
Ceci est un inconvénient important car les mines modernes peuvent être équipées d'un magnétomètre à 3 axes trirectangles cable de mesurer la simultanéïté de l'annulation de la variation suivant les trois composantes. Cette mesure permet de détecter la présence du dragage, et de mettre la mise de feu en veille.This is a major drawback because modern mines can be equipped with a 3-axis magnetometer with trirectangles cable to measure the simultaneity of the cancellation of the variation according to the three components. This measurement makes it possible to detect the presence of dredging, and to put the firing on standby.
Pour contrer ce moyen de détection, l'invention propose un système selon la revendication 1.To counter this detection means, the invention provides a system according to claim 1.
D'autres particularités et avantages de l'invention apparaîtront clairement dans la description suivante faite à titre d'exemple non limitatif en regard de la figure annexée qui représente schématiquement un bidon selon l'invention relié à des moyens de génération des courants d'alimentation des solénoïdes de ce bidon.Other features and advantages of the invention will appear clearly in the following description given by way of nonlimiting example with reference to the appended figure which schematically represents a container according to the invention connected to means for generating supply currents solenoids from this can.
Chaque bidon 103 remorqué par le dragueur est équipé, en plus d'un solénoïde longitudinal 201 connu, d'une bobine plate horizontale 221.Each can 103 towed by the dredger is equipped, in addition to a known
Les deux bobines sont alimentées par le même courant I(t) provenant d'un générateur 204 via 2 amplificateurs 205 et 215.The two coils are supplied by the same current I (t) coming from a
Un déphaseur 222 de
Les deux bobines ainsi alimentées délivrent un champ tournant dans un plan vertical parallèle à l'axe de déplacement du bidon et du bâtiment tracteur.The two coils thus supplied deliver a field rotating in a vertical plane parallel to the axis of movement of the container and of the tractor building.
En tenant compte des surfaces respectives des 2 bobines, le nombre de spires est adapté pour que les composantes du champ soient égales afin d'obtenir un module constant du champ produit, qui est donc circulaire.By taking into account the respective surfaces of the 2 coils, the number of turns is adapted so that the field components are equal in order to obtain a constant modulus of the field produced, which is therefore circular.
A titre d'exemple numérique, on donne:
- Dimensions du solénoïde :
diamètre ≃ 1,2m
longueur : 3,5 m - Dimensions de la bobine horizontale :
longueur : 3,5 m
largeur : 1, 2 m
hauteur : 0,15 m
- Solenoid dimensions:
diameter ≃ 1.2m
length: 3.5m - Dimensions of the horizontal coil:
length: 3.5m
width: 1, 2 m
height: 0.15 m
En dehors du fait que les 3 composantes de simulation du champ ne s'annulent plus simultanément, un tel dispositif procure en outre les avantages suivants :
- émission permanente pour une puissance crête optimisée ;
- uniformité de l'influence dans le sens longitudinal ;
- très bonne répartition des composantes verticale et longitudinale.
- permanent emission for optimized peak power;
- uniformity of influence in the longitudinal direction;
- very good distribution of the vertical and longitudinal components.
De ce fait, on simule beaucoup mieux la signature magnétique d'un bâtiment en se rapprochant davantage de la réalité.As a result, we can simulate the magnetic signature of a building much better by getting closer to reality.
Claims (2)
- Magnetic sweeping system comprising a sweeper towing a device for simulating the magnetic field of a ship of predetermined characteristics, this device comprising an assembly of solenoids towed in parallel and supplied with a variable electrical current which enables the magnetic field emitted by the solenoids to be varied over time so as to simulate the passage of a ship having the said predetermined characteristics, characterised in that the simulation device (103) furthermore comprises an assembly of flat coils (221), which are associated respectively with the solenoids (201) and the axis of which is perpendicular to the axis of the associated solenoid, and means (204, 205, 215, 221) for supplying the flat coils with the same currents as the solenoids with a π/2 phase shift in order to obtain a rotating magnetic field.
- System according to Claim 1, characterised in that the dimensions of the flat coils (221) and the values of the supply currents permit a circular field to be obtained.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8813873 | 1988-10-24 | ||
| FR8813873A FR2638135B2 (en) | 1988-04-19 | 1988-10-24 | MAGNETIC DREDGING SYSTEM |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0366522A1 EP0366522A1 (en) | 1990-05-02 |
| EP0366522B1 true EP0366522B1 (en) | 1992-12-16 |
Family
ID=9371219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19890402863 Expired - Lifetime EP0366522B1 (en) | 1988-10-24 | 1989-10-17 | Magnetic mine-sweeping system |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0366522B1 (en) |
| DE (1) | DE68903925T2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE467819B (en) * | 1990-01-22 | 1992-09-21 | S A Marine Ab | SET AND DEVICE FOR CONTROL OF MULTIPLE ELECTRODE SWIP |
| FR2666559B1 (en) * | 1990-09-11 | 1995-07-21 | Thomson Csf | MAGNETIC DREDGING SYSTEM. |
| FI112852B (en) * | 1999-07-06 | 2004-01-30 | Elesco Oy | minesweeping |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR862405A (en) * | 1939-12-19 | 1941-03-06 | Telephonie Ind Commerciale | Magnetic mine neutralizer |
| FR862813A (en) * | 1940-01-10 | 1941-03-17 | Device against underwater mines | |
| FR1188684A (en) * | 1956-12-11 | 1959-09-24 | Licentia Gmbh | Device for magnetic minesweeping |
| US3939753A (en) * | 1974-05-15 | 1976-02-24 | The United States Of America As Represented By The Secretary Of The Navy | Three axis coil magnetic minesweeping system |
-
1989
- 1989-10-17 EP EP19890402863 patent/EP0366522B1/en not_active Expired - Lifetime
- 1989-10-17 DE DE1989603925 patent/DE68903925T2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0366522A1 (en) | 1990-05-02 |
| DE68903925T2 (en) | 1993-04-22 |
| DE68903925D1 (en) | 1993-01-28 |
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