SU1377703A1 - Apparatus for continuous control of tape moisture content - Google Patents

Abstract

The invention relates to the field of measurement technology and can be used to control the humidity of moving strip materials. The aim of the invention is to improve the accuracy of moisture control by eliminating the influence on the measurement result of the belt tension value. The device contains a system for converting ribbon oscillations into frequency,: a belt tension modulator, a quadrator, modulator control elements, and parameters for calculating the parameter from the humidity / frequency conversion frequency values. The purpose of the invention is achieved by eliminating the influence of the nat5-value of the tape on the measurement result. 1 il., D

Description

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The invention relates to a measurement technique and can be used to measure the humidity of moving strip materials, in particular paper and cardboard.

The purpose of the invention is to improve the accuracy of controlling the moisture content of the rewindable strip material by eliminating the influence of the tension of the tape.

The drawing is a diagram of the device

The device contains the exciter 1 mechanical oscillations of the tape 2, a sensor 3 for moving a tape of the nozzle-damper type with a capacitive pressure-to-electric converter 4, a signal., Positive feedback circuit 5, a load 6, an electromagnet 7, an elastically installed melting shaft 8, a generator 9, elements 10 and 11, reversible counter 12, register 13, output reading device 14,. the quad 15 and the delay element 16 performed on the AND-HE elements 17 and 18, the diode 19 and the capacitor 20, the Elements 6, 7, 8 fulfill the function of the belt tension modulator.

The oscillation frequency of the flat ppasti is determined from

f

/ jm-,

a, - P - h -, P where m is the number of half-waves;

plate length;

plate density;

thickness ppastiny;

tension The structure of the material in the process of control is unchanged and its density is determined only by the moisture content of the material, t, e, p is proportional to W, therefore, ceteris paribus

fn

to |

where K is a constant coefficient.

When reducing the tension on a given value of the frequency

one

TO

R - PC g. L (w

Material moisture is determined by frequency difference.

„To P.

   f - 1 1.

The device works at once.

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Under the action of the exciter 1 in the system the exciter 1 - tape 2 - sensor 3 due to positive feedback 5 oscillations arise, the frequency of which is determined by the resonant properties of the tape. When the humidity of the tape increases, its mass increases, and, as a result, the resonant frequency of the system decreases. In the initial state, the counter 12 is reset. The first impulse (front edge) from the direct output of the generator permits, with the rewriting of information from counter 12 to register 13, the electromagnet 7 is simultaneously turned on, connecting additional load 6 to the melting shaft 8. Thus, the tension of the tape 2 decreases by At the same time, the element opens And 10 and

f

Frequency G is fed to the subtracting input of the reversible counter 12. At the moment of the appearance of a pulse at the inverted output of the generator 9 (at the direct output o) the element 10 closes and the element 11 opens, the electromagnet 7 is turned off. The frequency f through the Element And 11 enters the summing input of the counter. When the next pulse appears at the generator's direct output, rewriting of the difference of the squares of frequencies (f) into the register 13 is permitted, and through the delay element 16, the counter 12 is reset. In each case, the delay element 16 eliminates the influence of the modulator transient when the load 6 is connected to the shaft 8, the transient time (switching the modulator on and off) is in the order of 1-2% of the measurement time. This operation is repeated every period. The result (f, -f) is fed to the output reading device 14, which is scaled in units of humidity,

Quadriration of frequency f, (f 7.) produced by converter 4, is carried out using a quad 15, the input of which is connected to the output of converter 4, and the output is connected to the information inputs of And 10, And

The generator 9 generates direct shock pulses with a duty cycle equal to

I The delay element I6 accumulates a short negative pulse at each leading edge of the generator 9 pulses (direct output). Duration

0 W

Claims (1)

F. r m ul a inventions ιθ A device for continuously monitoring the humidity of the tape, containing the correct shafts, the causative agent of mechanical vibrations of the tape, a nozzle-flap motion sensor with a capacitive pressure transducer into an electric signal and a positive feedback circuit connecting the converter output to the oscillation exciter 20, characterized in that , in order to improve the accuracy of humidity control by eliminating the influence of tape tension, it additionally contains a load, an electromagnet, a generator of rectangular pulses by it, an element And, el a delay element, a reversible counter, a register, an output counter and a quadrator, one of the correct shafts being installed elastically and connected via an electromagnet to a load, the direct output of the generator is connected to a control input of an electromagnet, an enable register overwriting input, one of the inputs of the first AND element, and delay element - with the reset input of the reverse counter, the inverse output of the generator is connected to one of the inputs of the second element And, the output of which is connected to the input of addition of the reverse counter, the subtraction input which is connected to the output of the first AND element, the inputs of the register are bitwise connected to the outputs of the reversible counter, and the outputs are connected to the inputs of the output reading device, the second inputs of the AND elements are connected through the quadrator to the output of the pressure transducer into an electrical signal.