al sensor differential magnetic field probe adjustment - using mild steel movable pieces on carrier or retractable sensor wires

摘要

An arrangement enabling adjustment of magnetic differential field detectors contg. two sensors enables the accuracy to be considerably increased compared to conventional arrangements. This is achieved simply and results in a considerably cheaper detector applicable to ship defence equipment responding to noise fields much weaker than the earth's magnetic field. The sensors have mild steel pieces on or near them and movable in one or more directions or are constructed with movable components. The movable elements can be fixed in position. If separate mild steel pieces are used, they are rings, cylinders, discs or segments movable on an magnetic carrier ring on the probe. If the sensors have movable components these may consist of wires retractable and able to be bent w.r.t. them.