Inductive coupling apparatus for use in coupling to underwater electric systems and the like

SWEDEN

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PUBLISHING WRITING No. 326 490 ι «α H 01 f 31/10 Kl. 21 d² 49

PATENTS AND REGISTRATION OFFICE

Patent Application. No. 9131/66 Received on 5 VII 1966 Validity Day on 5 VII 1966

Ans. generally available on 1 VII 1968

Ans. laid out and the pamphlet published 27 VII 1970

Priority requested from 9 IX 1965 (USA, 486 112)

EG &amp; G. IOTOTÄTIONAL, INO., BEDFORD, MOUSE. USA

Inventor! KE Ferry

Representative: L Holmqvist

Apparatus for inductively connecting a live cable to e.g. a monitoring instrument

The present invention relates to an apparatus for inductively coupling a live cable to an electrical system, e.g. a monitoring measuring instrument having multiple connection contacts and housed in a sealed, watertight housing, which is applicable to a predetermined portion of the cable, wherein an annular magnetic core encloses a portion of the cable at said predetermined portion;

In the system of this nature, inductive coupling has been provided by means of annular magnetic cores on which field generating coils are wound and through which the cable is passed, the coils being connected to the system within the housing by external connections. However, after prolonged use in seawater and the like, corroded the core surfaces, which is why they must be replaced. This requires not only extensive restoration of the apparatus but the necessity of replacement with another relatively expensive coiled portion. However, in accordance with the present invention, the necessity of wound cores is completely eliminated and the replacement with and insertion of new cores is greatly simplified and facilitated by the use of a new single loop coupling which is readily applicable to a two-piece core structure.

One object of the invention is thus to provide a new and improved, greatly simplified and less expensive inductive coupling device, which is particularly suitable for underwater use.

For the purpose of this purpose, the apparatus according to the invention is characterized in that the core encloses the cable at such a distance from it that at least one conductive loop extending from an outer casing connection contact for the electrical system can pass through the core opening adjacent said part of the cable. but without electrical contact with the core and cable and from there back outside the core to a second connection connector for the system, whereby the system and the cable are inductively connected.

The invention will now be described in connection with the accompanying drawing, which is a parallel perspective view of a preferred embodiment of the apparatus according to the invention.

The drawing shows a sensing, monitoring or other instrument comprising an electrical system with dashed lines at 1 housed in a waterproof, closed, cylindrical casing 2 and at the ends clamped at 3 on an insulated, metal wire-reinforced conductive cable 4 serving as part of the signal transmitting transmission line system to complete the circuit for transmitting signals to or from system 1, as is well known. The complete transmission circuit can

e.g. extend from the sea: along the insulated cable 4 through the vessel monitoring equipment and back to the sea.

In accordance with the invention, an annular magnetic core (preferably cylindrical) is formed in two parts 5 and 5 'supported in two separate block sections 6 and 6' of non-magnetic material such as aluminum or plastic. The portion 6'-5 'is mounted on the casing 2 by one or more supporting rods 7 · A single loop (or loops) of insulation-coated wire is then extended at L from an externally waterproof end contact 8 through the opening in the core portion 5' adjacent the cable 4 and from there. back at L ', outside block 6', to a second end contact 8 *. The second portion 6-5 may then be connected to or secured to the portion 6'-5 ', e.g. by means of screws 9, completing the core 5-5 'and enclosing the cable 4, which passes through the core opening, without electrical contact with its walls. The isolation of loop L prevents electrical contact with both cable 4 and core 5-5 'but enables inductive coupling to the adjacent portion of cable 4 passing through the core. Thus, only the cheap core itself needs to be replaced if it is rusted, bare and bare, by separating the block portions 6 and 6 'apart and without the previously required replacement of expensive pre-welded cores. The use of the loop L1, moreover, makes it possible for a stronger and more durable wire to be used than in the winding of pre-wound core structures. The easy attachment for connection to the cable is of course obvious.

However, since the loop coupling to the cable 4 is not as large as 10 can be achieved with multi-ply wound cores, the total coupling to the system 1 can be increased by a transformer or similar device T inserted between the end contacts 8, 8 'and the system 1 inside. the house 2.