SU1497530A1 - Moisture meter - Google Patents

Abstract

The invention relates to measuring means for measuring the moisture content of veneers and other sheet materials. The purpose of the invention is to improve the measurement accuracy and expand the scope. Two electronic keys and a sensor of the presence of the monitored material in the measurement zone are entered into the device, the output of which is connected to the control inputs of electronic switches, the signal inputs of which are connected to the outputs of the synchronous detector, and the outputs to the inputs of the integrators. If there is a controlled material, the electronic keys are open and the signals of the working and reference channels are fed to the inputs of the respective integrators. 1 il.

Description

The invention relates to a measurement technique and is intended, in particular, for measuring the humidity of in-line, produced veneer and other sheet materials.

The purpose of the invention is to increase the measurement accuracy and expand the field of application.

The drawing shows the functional diagram of the proposed moisture meter.

The moisture meter contains a radiation source 1 that irradiates the material being monitored 2. The radiation reflected from the material being monitored is directed to the modulating disk 3 with light filters and to the sensor 4 the presence of the material being monitored. The radiation receiver 5 through the pre-amplifier 6 is connected to the input

synchronous detector 7. The modulating disk 3 acts on the generator input 8 synchronous pulses, the output of which is connected to the control input of the synchronous detector 7. The outputs of the synchronous detector 7 are connected to the signal inputs of the electronic switches 9 and 10 of the working and reference channels, respectively. The control inputs of the electronic switches 9 and 10 are connected to the output of the sensor 4 by the presence of controlled material. The outputs of the electronic switches 9 and 10 are connected to the inputs HHterparopOB 11 and 12. The outputs of the latter are connected to the inputs of the dividing unit 13, the output of which is connected to the input of the measuring unit 14.

The sensor of the presence of the controlled material is a photoref of the CO JV

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There are two symmetric channels, each containing a photodiode, a current-voltage converter, a low-pass filter, and a comparator. The output of the comparator is connected to one of the inputs of the AND 2 logic circuit, the output of which through the logic inverter is connected to the control input of one of the analog switches. A signal from a generator of synchronous signals is supplied to the second input of the circuit AND 2,

Headlamp incandescent lamps operating in iodine dickel with intense infrared radiation are used as a source of radiation.

The moisture meter works as follows.

The radiation source 1 is irradiated with controlled material 2, while a part of the radiation flux is absorbed by the water molecules contained in it, and a part is reflected and enters the passage through the light filters installed on the modulating disk 3 to the receiver 5 emit.

The passbands of the filters are selected respectively by the equal lengths: maximum waves (working wavelength) and minimum (reference wavelength) absorption by water molecules.

The radiation receiver 5 converts the optical pulses into electrical pulses, which are amplified by the preamplifier 6 and are fed to the input of a synchronic detector 7.

The operation of the synchronous detector 7 is controlled by a generator of 8 synchronous pulses connected to its control input. Synchronous pulses provide alternate transmission of the reference and working signals from the synchronous detector, respectively, to the signal inputs of the electronic switches 10 and 9 of the reference and working channels, respectively.

The electronic keys 9 and 10 control the sensor 4 for the presence of a monitored material. At the same time, in the presence of controlled material 2 in the measurement zone, when at both inputs of the And 2 circuit, there will be a genital level of logical units, i.e. when a sheet of material overlaps the field of both photodiodes of the sensor of the presence of controlled material electronic keys 9 and 10 are open and

signals of the working and reference channels are fed to the inputs of integrators 1 1 and 12, respectively, of the working and reference channels,

From the output of the integrators 11 and 12, a constant voltage, proportional to the amplitude of the working and reference channels, is fed to the inputs of dividing unit 13, at the output of which a signal is formed that is proportional to the controlled material, which is fed further to the measuring unit 14. When the monitored material leaves the zone measuring sensor 4 the presence of the monitored material generates a signal that closes the electronic keys 9 and 10. At the same time, the signal level of the working and reference channels is memorized on the integral purifying, integrator capacitors 11 and 13. The magnitude of the DC voltage at their outputs remains unchanged until the opening electronic switches 9 and 10, i.e. until the measurement of the next sheet of controlled material in the measurement zone. Accordingly, the signal at the output of dividing unit 13 and the readings of measuring unit 14 remain unchanged.

When a monitored material appears in the measurement zone, the monitored material sensor 4 generates a signal opening the electronic keys 9 and 10. The signals from the working and reference channels from the output of the synchronous detector 8 are fed to the input of the integrators 11 and 12 and further to the 5th unit of the dividing unit 13. At the output of block 1 3 of the division, a sinal is formed, proportional to the humidity of the next sheet (the next pore) of the material being monitored.

With the passage of successive pores of the controlled material through the measurement zone, the device operates in a similar way.

Claims (1)

Invention Formula A moisture meter containing a radiation source, along the rays of which there is a modulating disk with light filters and a series-connected radiation receiver, a preamplifier, a synchronous detector, the speaker inputs of which are connected to a generator of synchronous pulses. optically connected with a modulating disk, as well as two integrators connected by outputs to a dividing unit whose output is connected to a measuring unit, characterized in that, in order to increase measurement accuracy and expand the range of application of the moisture meter, Two electronic keys and a sensor for the presence of the monitored material in the measurement area, to the output of which are connected the electronic inputs of electronic switches, the signal inputs of which are connected to the outputs of the synchronous detector, and the outputs to the inputs of integrators.