SU1578451A1 - Apparatus for measuring thickness of layers of laminated articles - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the thickness of pavement layers. The purpose of the invention is to improve the measurement accuracy due to the localization of the control zone - due to the fact that the inductive converter is made in the form of a nonmagnetic shaft mounted for rotation, placed in the grooves of the inductor shaft and mounted on the shaft of the magnetic inductance surrounding the inductor of the magnetic screen shaft, and the sensor of the angular displacement of the shaft, and the measurement unit is made in the form of series-connected differential amplifier connected to the inductance, linear rectifier, logarithmic amplifier, subtraction unit, adder, anti-log amplifier, second subtraction unit and thickness indicator connected to the output of an angular displacement sensor of a shaft of a series-connected inverter, second adder, sinusoidal voltage maker and second logarithmic amplifier whose output is connected to the second the input of the first adder connected to the sensor of the angular displacements of the shaft of the second sinusoidal voltage generator connected in series and, a multiplier, a distance indicator, as well as a second anti-log amplifier, connected between the output of the first subtraction unit and the second input of the multiplier, and a block of reference voltages, the outputs of which are connected to the second inputs of the second adder, first and second subtractors. 3 il.

Description

adder 6. As well as serially connected second shaper 14 sinusoidal voltage, multiplier 15 and distance indicator 16. The device also contains a second anti-log amplifier 17, connected between the output of subtraction unit 5 and the second input of multiplier 15, and reference voltage unit 18, the outputs of which are connected to the second inputs of the second adder 11, first and second blocks 5, 8.

The inductive converter 1 is made in the form of a non-magnetic shaft 19 rotatably mounted in the grooves of the shaft of the inductor 20 fixed on the shaft of the magnetic shield 21 with the slit 22 along the generator of the shaft and the sensor 23 of the angular displacement of the shaft enveloping the inductor 20 of the shaft an inverter 10 and a second sinusoidal voltage driver 14 are connected.

A device for measuring the thickness of the layers of multilayer products works as follows.

During construction, linear conductors 24 are placed between the layers of the pavement.

In the course of the measurement, alternating electric current is passed through the linear conductor 24, the device is installed above the linear conductor in such a way that the magnetic induction vector is orthogonal to the planes of the turns of the inductor coil 20 of the inductive converter 1, and the magnetic screen 21 is positioned along the conductor 24. In this position, the value of the EMF of the converter 1 is maximum, and its average value

E-2f.k. .ts..ip.-05Shf1-A ° g "2T

(one)

To linearize the characteristics of the converter, voltage I is fed to a logarithmic amplifier 4, from the output of which the voltage is fed to the input of subtraction unit 5, the second input of which simultaneously supplies voltage Uz-logK .A from the block 18 of reference voltages and from the output of block 5 subtracting the voltage L / 4 logK A-logU is fed to the input of the anti-log amplifier 17 at the output of which the voltage Ub antilog

KiA

(logKiA-logUi) C

Go, which is proportional to the distance Go from the transducer 1 to the linear conductor 24 located between the pavement layers. The thickness h of the pavement layer is determined from the ratio of irocosa-Ho, where a is the angle of rotation of the converter relative to the vertical; But - the distance of the axis of rotation of the converter to the road surface.

To convert the angle and the rotation of the transducer into an electrical signal, use the sensor 23 of the angular displacement

shaft, made in the form of a resistive converter connected according to the voltage divider circuit, the voltage (D of which (.) from its positive contact goes to the input of the inverter 10, the output of which always has a negative voltage equal to the module Ue-C of the output of the inverter 10 it is fed to the input of the adder 11, the second input of which is supplied

positive voltage Ug-Ks-j- with blo &

ka 18 reference stresses. From the output of the adder, 11 voltages are fed to a sinusoidal voltage shaper 12, the output of which is formed

signal

where f is the current frequency;

kfW is the sum of the areas of the turns of the inductor;

u is the relative magnetic permeability of the material of the layer being measured; co is a magnetic constant; / o - the amplitude value of the current in

linear conductor; x f is the angular characteristic of the converter, determined by the parameters of the magnetic screen; r0 is the distance from the converter to

.line conductor. The signal from converter I is amplified by Differential amplifier 2, rectified by a linear rectifier 3, the output of which is a voltage, where K is the gain factor for the voltage of amplifier 2.

() cos a

TO

12

The voltage (/ h is converted by the logarithmic amplifier 13 into a voltage ((cos | a |)), which is fed to the input of the adder 6, to the second input of which voltage нап / 4 is applied from the subtraction unit 5.

The output voltage of the adder 6

f / i3 C / 4 + tfi2 / og J.cos | a |

C

is fed to the input of the antilog amplifier 7, the output voltage of which

Uu-antilog log (-icosa) r0cosa. submits

to the input of the subtraction unit 8, to the second input of which voltage is supplied from the unit 18 of the reference voltages. You

The feed voltage of subtraction unit 8 f / ie- - Ј / n-Ј / i5-rocosa-But is fed to the thickness indicator 9.

In addition to measuring the thickness of the pavement layers, the device allows determining the distance from transducer 1 to the projection of a point on the road surface in which the layer thickness is measured. For this, the output voltage of the sinusoidal voltage shaper 14 is supplied

Lz

the input of the multiplier 15, the second input of which receives the voltage. At the output of the multiplier 15, the voltage U s rosina, which is fed to the distance indicator 16.

Claims (1)

Invention Formula An apparatus for measuring the thickness of layers of multilayer products, comprising an inductive transducer and a measuring unit, characterized in that, in order to improve the measurement accuracy, the inductive transducer is made in the form of a non-magnetic shaft mounted for rotation, placed in the grooves of the shaft Ho Ho a carcass of inductance mounted on the shaft of a magnetic shield enclosing the inductance of a magnetic screen with a slit along the generator shaft, and an angular displacement sensor of the shaft, and the measuring unit is designed as a series-connected differential amplifier, linear, rectifier, logarithmic amplifier, subtraction unit, adder , an antilog amplifier, a second subtraction unit and a thickness indicator, connected to the output of the shaft angular displacement sensor, are connected in series x inverter, second adder, sinusoidal voltage mapper and second logarithmic amplifier, the output of which is connected to the second input of the first adder, connected to the sensor of angular displacements of the shaft connected in series to the second sinusoidal voltage maker, multiplier and distance indicator, and also the second anti-logarithm amplifier, connected between the output of the first subtraction unit and the second input of the multiplier, and the block of reference voltages, the outputs of which are connected to the second input said second adder, said first and second subtracting units. 0 1 y with t--. Yu 22 21 Fig.Z