Magnetizing means for a magnetic flaw detector including a charging and discharging circuit

Claim 2

Apparatus for magnetically detecting flaws in a magnetisable object, the said apparatus comprising a first circuit having a storage capacitor therein and adapted to be connected across a D.C. battery; a second circuit comprising a series circuit including the said storage capacitor, a thyristor, and two conductors each extending to a permanent magnet and wound about said magnet, said magnet magnetically connecting said conductors and the storage capacitor to the object; a third circuit comprising the said thyristor and adapted to be connected across the said D.C. battery; and a multi-position switch connected in both the first and third circuits, the switch having a first position in which the second and third circuits are open-circuited and in which the first circuit is completed to effect charging of the storage capacitor by the D.C. battery, and the switch having a second position in which the first circuit is open-circuited and the third circuit is closed, such closure of the third circuit causing the thyristor to close the second circuit whenever said object is connected between the conductors, and thus causing the storage capacitor to be hyperbolically discharged and to generate magnetic flux in the object.

Claim 3

Apparatus as claimed in claim 1 in which the total resistance of the conductors does not exceed 20 milliohms.

Claim 4

Apparatus as claimed in claim 1 in which each conductor comprises a compressible material.

Claim 5

Apparatus as claimed in claim 1 in which each conductor is insulated from its permanent magnet.

Claim 6

Apparatus as claimed in claim 1 comprising means for detecting current flow through one of said conductors.

Claim 7

Apparatus as claimed in claim 1 in which each permanent magnet has a recess therein, a conductor disposed in said recess, and a resilient member which is disposed in said recess and which urges the conductor outwardly of the recess, application of the permenent magnet to said object causing the conductor to be compressed against the resilient member.

Claim 8

Apparatus as claimed in claim 6 in which the conductor is wrapped about the permanent magnet so as to have a plurality of turns in said recess.

Claim 9

Apparatus as claimed in claim 1 in which one of said conductors is disposed adjacent to a magnetisable member, the magnetisable member having at least one aperture therein, a transparent member, the magnetisable member defining with the transparent member a chamber the interior of which can be seen through the transparent member, and magnetisable particles in said chamber which, when a current passes through the conductor, become aligned with the said at least one aperture.

Claim 10

Apparatus as claimed in claim 8 in which the conductor passes through a hole in the magnetisable member, the said aperture being a drilling spaced from said hole.

Claim 11

Apparatus as claimed in claim 8 in which the magnetisable particles are dispersed in a liquid in said chamber.

Claim 12

Apparatus for magnetically detecting flaws in a magnetisable object, said apparatus comprising: a first circuit having a storage capacitor therein and adapted to be connected across a D.C. battery; a second circuit comprising a series circuit including said storage capacitor, a thyristor, and two conductors each extending to a permanent magnet and wound about said magnet; a magnetisable core adapted to have the object connected between its ends to form a magnetic circuit, an inductor coil for magnetising the core, terminals connected to the inductor coil and adapted to be contacted by the permanent magnets, said permanent magnets magnetically connecting said conductors and the storage capacitor to said inductor coil; a third circuit comprising said thyristor and adapted to be connected across said D.C. battery; and a multi-position switch connected in both first and third circuits, the switch having a first position in which the second and third circuits are open circuited and in which the first circuit is completed to effect charging of the storage capacitor by the D.C. battery, and the switch having a second position in which the first circuit is open circuited and a third circuit is closed, said closure of the third circuit causing the thyristor to close the second circuit whenever said inductor coil is connected between the conductors thus causing the storage capacitor to be discharged and to generate a magnetic flux in the magnetisable core and in the object.

Claim 13

Apparatus for magnetically detecting flaws in a magnetisable object, said apparatus comprising: a first circuit having a storage capacitor therein and adapted to be connected across a D.C. battery; a second circuit comprising a series circuit including said storage capacitor, a thyristor, and two conductors each extending to a permanent magnet and wound about said magnet; a magnetisable core adapted to have the object connected between its ends to form a magnetic circuit, an inductor coil for magnetising the core, terminals connected to the inductor coil and adapted to be contacted by the permanent magnets, said permanent magnets magnetically connecting said conductors and the storage capacitor to said inductor coil; a third circuit comprising said thyristor and adapted to be connected across said D.C. battery; and a multi-position switch connected in both first and third circuits, the switch having a first position in which the second and third circuits are open circuited and in which the first circuit is completed to effect charging of the storage capacitor by the D.C. battery, and the switch having a second position in which the first circuit is open circuited and a third circuit is closed, said closure of the third circuit causing the thyristor to close the second circuit whenever said inductor coil is connected between the conductors thus causing the storage capacitor to be discharged and to generate a magnetic flux in the magnetisable core and in the object.