Method and apparatus for compensation of interference magnetic fields
OwnerFriedrich M. O. Forsterinventor
Life of this patent
Estimating the term…
Abstract
Compensating magnets are located on the article being tested which are adjustable to provide a range of magnetic moments. In a first version, each compensating magnet consists of an annular permanent magnet received on a rod-like element positioned on the surface of the article, which magnet is adjustable with respect to the article surface. In a second version, the magnet is located at a fixed spacing with respect to the article surface and a shunt is adjustable to vary the compensating field.
Claims15
A method for stable compensation of the magnetic interference fields produced by the vertical component of the earth's magnetic field in the vicinity of an article including a housing and components therein in which a compensation moment opposite to the magnetic moment induced in the article by the vertical component is produced and the article is also subjected to a vertically directed alternating magnetic field with decaying amplitude, which comprises the steps of:
- locating at least one permanent magnet adjacent an outer surface of the article;
- adjusting the magnetic moment induced in the article by the permanent magnet to compensate for the effect thereon of the earth's magnetic field vertical component;
- and
- subjecting the article to an alternating magnetic field with decaying amplitude.
Apparatus for inducing a selective magnetic moment in an article to compensate for the effect of an external magnetic field, comprising:
- a threaded bolt of non-magnetic material, an end of which is affixed to the outer surface of said article;
- and
- an internally threaded annular magnet received on said bolt and adjustable therealong to vary the relative spacing of said magnet from said article outer surface.
Apparatus for inducing a selective magnetic moment in an article to compensate for an external magnetic field, comprising:
- a hollow tube of non-magnetic material, one end of which is for attachment to said article;
- an elongated magnet fixedly located within said tube;
- and
- a ferromagnetic body having an opening therethrough receiving said tube therein and adjustable along said tube for shunting said magnet.
Dependencies are inferred from the claim text.