SU868658A1 - Device for measuring magnetic field intensity - Google Patents

Description

The invention relates to the measurement of the voltage of low-frequency weak magnetic fields and can be used in geophysical as well as biomedical research.

Sensors for flaw detection based on the Barkhausen effect, consisting of one ferromagnetic rod and one induction solenoidal HP coil, are known.

The disadvantage of the device is low sensitivity and the absence of Barkhausen impulses at their output when the field voltage changes in the direction of decreasing.

Naibo. Its close to the proposed technical solution is a sensitive indicator of the change of the magnetic field, based on the Barkhausen effect, containing a ferromagnetic core, with an induction solenoid coil placed on it, and a biasing coil U21.

The drawback of the device lies in its low sensitivity and the absence of Warkhausen pulses on its output when the voltage changes in the direction of decrease.

The purpose of the invention is to increase the sensitivity and accuracy.

The goal is achieved

5 by the fact that a second and third are introduced into the device containing a cylindrical core with an induction solenoid coil and a biasing coil located on it,

10 parallel and identical to the first, cores with induction solenoid coils placed on them, all three cores are fitted with attached to each

1- along forming four thin rectangular, 90 ° shifted relative to each other by ferromagnetic plates, as well as three sub-magnetized coils, induction solenoid coils are placed coaxially in shielding cylindrical glasses with dielectric pads, and four biasing coils are wound perimeter along

JC of the longitudinal axis of the ferromagnetic plates of the first core, the first induction solenoid coil, first, second, third and fourth biasing coils, the second and third induction solenoid coils are connected in series respectively.

FIG. 1 shows the device a general view; in fig. 2 — graphs of changes in the intensity of the measured field and the output signal.

The device contains dielectric rods 1-3, thin ferromagnetic plates 4, induction solenoid coil 5, biasing coils 6-9, second induction solenoid coil 10, third induction solenoid coil 11, shielding cups 12-14 and dielectric pads 15-17.

The device works as follows.

When a primary converter is placed into an alternating magnetic field in a ferromagnet, a domain re-orientation occurs abruptly, causing induction solenoids of 5, 10, and 11 EMF pulses (Barkhausen jumps), which are transmitted to magnetic bias coils 6-9, creating a pulse magnetizing field makes a small acute angle with the measured one, which leads to the grouping of 1 Barkhausen's very large jumps into large ones.

At the output of the primary converter, a pulsed signal is obtained equal to the sum of signals received in induction solenoid coils 5, 10 and 11 from Barkhausen single jumps, pulses caused by magnetic bias, and pulses produced in ferromagnets by a pulsed field created by bias coils 6 - 9.

Due to the fact that two adjacent Barkhausen pulses occur when the external field changes to a strictly deterministic value for a given ferromagnet, then the time between the passage of the previous and subsequent pulses t is strictly dependent on the rate of increase or decrease of the measured field intensity (Fig. 2ai 2b).

Moreover, the pulse signal at the output of this primary converter is in the sign dependence on the intensity of the measured magnetic field (Figs. 2a and 26).

The proposed primary transducer has a sensitive sensitivity and the sign of its output signal is determined by the direction of change of the measured field. The proposed primary transducer can be used in geophysical and biomedical research.

Claims (2)

1.Lomaev G.V. The method of magnetic noise in the destructive testing of ferromagnets. - Flaw detection, 1977, No. 4 2. Kharitonov Yu.N. Sensitive magnetic field change indicator based on the Barkgauzia effect. Instrumentation and Experimental Technique, 1966, 6.