SU1509763A1 - Meter of properties of magnetic liquids - Google Patents

Abstract

The invention relates to magnetic measurements and can be used to test magnetic fluids and to study their properties. The aim of the invention is to make it possible to measure the magnetic properties of the local portions of the volume of the magnetic fluid. The measuring instrument of properties of magnetic fluids consists of measuring coil 1, resistor 2, source 3 of magnetizing current, voltmeter 4, inverting amplifier 5, adder 6, amplifier 7 and integrator 8. Magnetic liquid 10 is filled in vessel 9 and after settling, induction is measured in several sections after each measurement, the measuring coil 1 is moved in the vertical direction. The use of a frameless measuring coil made in the form of a torus makes it possible to reduce the influence of the field of the coil on the properties of the test liquid. 1 il.

Description

SP

about

QD

O) 00

150

This invention relates to the field of

magnetic measurements and is intended to test magnetic fluids and study their properties.

The purpose of the invention is to make it possible to measure the magnetic properties of local areas of the magnetic fluid volume.

The drawing shows a structural diagram of the gauge properties of magnetic fluids.

The measuring instrument of properties of magnetic fluids consists of measuring coil 1, resistor 2, source 3 of magnetizing Current, voltmeter 4, inverting amplifier 5, adder 6, amplifier 7 and integrator 8.

A measuring coil 1 is immersed in the vessel 9 with the test magnetic fluid 10, to the first output of which one output of the source 3 of the magnetizing current is connected, another end of which is connected to the first output of the resistor 2, the second output of which is connected to the second output of the measuring coil 1, and to the outputs of the resistor 2 is connected to a voltmeter and input terminals of an inverting amplifier 5, the output of which is connected to the first input of the adder 6, the output of which is connected to the output bus through the integrator 8, the second input is connected to the output of the amplifier 7, the input terminals of which are connected to the terminals and the end of the measuring coil 1,

The meter works as follows.

The measuring coil 1, having openings between the turns in its outer part, is placed in the vessel 9 with the tested magnetic fluid 10, which fills its cavity, flowed through the openings between the turns of its winding on the outer generatrix surface. The output current of the source 3 of the magnetizing current flowing through the measuring coil 1 and the resistor 2 changes its value from zero to the desired value. The voltage drop across the resistor 2 determines the strength of the magnetic field in the measuring coil. This is used in the formula

U-WK.

H

R b

where H is the value of the magnetic field strength in the measuring coil;

0

0

five

Q

five

0

five

0

five

and - voltage measured by a voltmeter 4 at the terminals of resistor 2;

W, is the number of turns of the measuring coil;

R is the resistance of resistor 2; 1- - average length of the power line

and

inside the measuring coil. During a current change, the voltage taken from the leads of the measuring coil 1 is amplified by the amplifier 7 and fed to the second input of the adder 6. The voltage drop across the resistor 2, proportional to the value of the current flowing through the measuring coil 1, is amplified by an inverting amplifier 5

Uebrx.My yw.ij, Kc. to IM, K where iru .; and, m output voltage

inverting amplifier 7;

To CPU If the gain of the inverting amplifier 7; 1ts - the current proceeding on

measuring coil; RH.K resistance measuring coil;

Kfl is the device conversion factor. The voltage at the terminals of the measuring coil during a change in the current flowing through the measuring coil is described by the expression

U.K .. to

where and a., is the voltage at the terminals of iz and 1 k,

measuring coil; Sf, is the sectional area of the measuring coil; W., - the number of turns of the measuring coil; B is the measured value of the rate of change of induction inside the measuring coil,

The voltage at the terminals of the measuring coil I is amplified by the amplifier 7:

ivy.a nUH.K -1-К „., 1and.k), where Vot.ch output voltage of the amplifier 9;

Kn is the device conversion factor.

The bias voltages of amplifier 7 and inverting amplifier 5 are supplied. to the inputs of the adder 6, the output voltage of which is proportional to the rate of change of the induction magnet5

OF THE FIRST FIELD inside the measuring cat. 1: OLS-C Uebu. y. Kn

+ 1.

m.k.

R

and to

)-to.

3. And to. I. to

The voltage from the output of the adder 6 is fed to the input of the integrator 8, at the output of which a signal proportional to the induction of the magnetic field appears.

To measure the homogeneity of magnetic fluids, magnetic induction values at constant magnetic field strengths are measured in several areas of the magnetic fluid vessel. The movement of the measuring coil 1 is carried out in the absence of a magnetizing current in its winding.

The determination of the sedimentation stability of magnetic fluids is carried out as follows. Magnetically

Claims (1)

The use of a frameless measuring coil made in the form of a torus makes it possible to reduce the effect of the field of the coil on the properties of the test liquid. Invention Formula A gauge of properties of magnetic liquid Q bones, containing a measuring coil, the first output of which is connected to the first output of the source at --- magnetic current and the first input of the amplifier, the second input to the second 5 amplifier and through a resistor to the second output of the magnetizing current source , the terminals of the resistor are connected to the corresponding inputs of the inverting amplifier, the outputs 0 of which are connected to the first input of the adder, the second input of which is connected to the output of the amplifier, and the output. through the integrator - with the output bus, and the resistor terminals are connected to liquid 10 is filled with vessel 9, after 25 with the corresponding voltmeter inputs. the time necessary for the study of the settling, induction measurements are made in several areas of the vessel filled with liquid, after each measurement the measuring coil 1 is moved in the vertical direction. The movement of the measuring coil 3 in this case is also carried out in the absence of a magnetized current. wherein the measuring coil is made toroidal with openings between turns, the dimensions of the measuring coil are selected from the required spatial resolution of the measuring properties of the magnetic fluid.