Apparatus for measuring the distance to the floor of the cargo hold of a ship through intervening bulk material
First Claim
1. Apparatus for measuring the distance to the floor of a large magnetically permeable container such as the cargo hold of a ship through intervening bulk material including a dipole field generating magnetic field radiator, a dipole field sensitive receiver antenna, said field radiator and receiver antenna being displaced from one another in a direction parallel to the floor of the cargo hold by a distance d at least equal to the dimensions of the radiator with the axis of the field of one parallel to the floor of the cargo hold and displaced therefrom a distance D which distance is the same order as d and with the axis of the field of the other intersecting and perpendicular to the axis of the field of the first and substantially perpendicular to the floor of the cargo hold, anda receiver circuit connected to the receiver antenna including a log converter for generating from the perturbations in said magnetic field produced by the magnetically permeable floor of the cargo hold and detected by the receiver antenna, a signal proportional to the distance D.
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Accused Products
Abstract
Apparatus for measuring the distance to and through magnetically permeable materials having a planar surface includes a dipole field generating magnetic field transmitting antenna and a dipole field sensitive receiver antenna. The antennae are displaced from one another in a direction parallel to the planar surface a distance d with the field axis of one antenna, preferably the transmitting antenna, parallel to the planar surface and with the axis of the field of the other antenna intersecting and perpendicular to the axis of the field of the first antenna and substantially perpendicular to the planar surface. With this arrangement, perturbations in the magnetic field caused by the magnetically permeable material induce a signal in the receiver antenna which is proportional to 1/D3 where D is the distance between the antenna and the planar surface and is of the same order as d. The effects of intervening or adjacent fixed or rotating magnetically permeable materials are nulled out geometrically and/or electrically.
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Citations
13 Claims
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1. Apparatus for measuring the distance to the floor of a large magnetically permeable container such as the cargo hold of a ship through intervening bulk material including a dipole field generating magnetic field radiator, a dipole field sensitive receiver antenna, said field radiator and receiver antenna being displaced from one another in a direction parallel to the floor of the cargo hold by a distance d at least equal to the dimensions of the radiator with the axis of the field of one parallel to the floor of the cargo hold and displaced therefrom a distance D which distance is the same order as d and with the axis of the field of the other intersecting and perpendicular to the axis of the field of the first and substantially perpendicular to the floor of the cargo hold, and
a receiver circuit connected to the receiver antenna including a log converter for generating from the perturbations in said magnetic field produced by the magnetically permeable floor of the cargo hold and detected by the receiver antenna, a signal proportional to the distance D.
Specification