RU2006842C1 - Moisture meter based on heat detector - Google Patents

Abstract

FIELD: instruments. SUBSTANCE: device has heat detector, analog-to- digital converter and computation unit. Computation unit has control unit, accumulating adder, four storage registers, two dividers, subtraction unit and three-state "reference-measuring" switch. EFFECT: simplified design. 1 dwg

Description

 The invention relates to measuring equipment, and in particular to means of non-contact humidity measurement of porous materials and products in construction, energy, and aviation technology.

 The purpose of the invention is to improve the accuracy of measuring the moisture content of porous materials by taking into account the influence of environmental conditions, such as temperature, humidity and air velocity near the surface of the material, the moisture content of which is measured.

 The drawing shows a functional diagram of a thermal imaging moisture meter.

 The thermal imaging moisture meter contains a thermal imager 1, an analog-to-digital converter 2, a computing device 3 containing an accumulating adder 4, four memory registers 5-8, a subtraction unit 9, dividing units 10, 11, a control unit 12 with a synchronization system, a three-position switch Standard - measurement and start button, indicator 13.

 The device operates as follows.

 In the field of view of the thermal imager 1 enter the reference dry product, similar to the studied. Set the three-position switch Etalon - measurement of the control unit 12 to the "Etalon" position and press the start button. Due to the sequential arrival of frame and horizontal sync pulses from the synchronization outputs of the thermal imager 1 to the synchronization inputs of the control unit 12, synchronous pulse sequences are formed at its outputs connected to the control input of the analog-to-digital converter 2 and the control input of the accumulating adder 4, respectively. An analog-to-digital converter 2 converts a voltage value proportional to the temperature at the thermal field points of a dry reference sample (the number of these points is determined by the number of decomposition points in the imager 1 raster) into a digital code that is input to the accumulating adder 4, which is the information input of computing device 3 .

, пропорциональные интегральному значению распределения температурного поля по поверхности сухого изделия Т

(х, у)
I

=

Т

(х, у)dx dy=

T

(х, у)= N˙T

, где S - площадь поверхности сухого эталонного изделия;
х, у - координаты i-й точки;
T

- температура в i-й точке;
N - количество точек в растре тепловизора 1.For a time interval equal to the duration of one frame, the value I is recorded in the accumulating adder 4

proportional to the integral value of the temperature field distribution over the surface of a dry product T

(x, y)
I

=

T

(x, y) dx dy =

T

(x, y) = N˙T

where S is the surface area of the dry reference product;
x, y - coordinates of the i-th point;
T

- temperature at the i-th point;
N is the number of points in the raster of the thermal imager 1.

, переписывается из накапливающего сумматора 4 в первый регистр 5, при этом сигналы управления на выходах блока 12, соединенных с управляющими входами аналого-цифрового преобразователя 2 и накапливающего сумматора 4 соответственно, отсутствуют.Upon receipt of the second frame sync pulse at the synchronization input 12 of the control unit at its output connected to the second input of the first register 5, a signal is generated according to which information about the value of I

, is copied from the accumulating adder 4 to the first register 5, while the control signals at the outputs of block 12 connected to the control inputs of the analog-to-digital converter 2 and the accumulating adder 4, respectively, are absent.

 An article is introduced into the field of view of the thermal imager 1, the moisture content of which is measured, the three-position switch of the block 12 is moved to the "Measurement" position, and the start button is pressed.

T(x, y)dx dy =

T_i(x, y), где Т_i(х, у) - температура в i-й точке на поверхности исследуемого изделия.In the accumulating adder 4, the value I is recorded, which is proportional to the integral of the distribution of the temperature field T (x, y) over the surface of the test article:
I =

T (x, y) dx dy =

T _i (x, y), where T _i (x, y) is the temperature at the i-th point on the surface of the test product.

переписывается из накапливающего сумматора 4 во второй регистр 6, при этом сигналы управления на выходах блока 12, соединенных с управляющими входами аналого-цифрового преобразователя 2 и накапливающего сумматора 4 соответственно, отсутствуют. При поступлении сигнала управления с выхода блока 12 на управляющий вход блока 9 вычитания информация о величинах I

и I поступает с выходов регистров 5 и 6 на первый и второй входы блока 9 вычитания соответственно. В блоке 9 формируется код, соответствующий разности I

- I. По сигналу с выхода блока 12, поступающему на управляющий вход третьего регистра 7, этот код поступает на первый вход третьего регистра 7, в котором запоминается.When the second frame sync pulse arrives at the synchronization input of block 12, at its output connected to the second input of the second register 6, a signal is generated according to which information about the value of I

is copied from the accumulating adder 4 to the second register 6, while the control signals at the outputs of block 12 connected to the control inputs of the analog-to-digital converter 2 and the accumulating adder 4, respectively, are absent. Upon receipt of the control signal from the output of block 12 to the control input of the subtraction block 9, information on the quantities I

and I comes from the outputs of registers 5 and 6 to the first and second inputs of the subtraction unit 9, respectively. In block 9, a code is generated corresponding to the difference I

- I. By the signal from the output of block 12, arriving at the control input of the third register 7, this code is fed to the first input of the third register 7, which is stored.

, пропорциональное интегралу от распределения температурного поля Т

(х, у) по поверхности эталонного влажного изделия
I

=

Т

(х, у)dx dy=

T

(х, у)= N˙Т

.In the field of view of the thermal imager 1, a wet reference product is introduced, which is in the same conditions (at the same temperature, humidity and air velocity in which the test product is located. The three-position switch of block 12 is put into the "Standard wet" position and the start button is pressed. accumulating adder 4 records the value of I

proportional to the integral of the temperature field distribution T

(x, y) over the surface of the reference wet product
I

=

T

(x, y) dx dy =

T

(x, y) = N˙Т

.

переписывается из накапливающего сумматора 4 во второй регистр 6, при этом сигналы управления на выходах блока 12, соединенных с управляющими входами аналого-цифрового преобразователя 2 и накапливающего сумматора 4 соответственно, отсутствуют. С выходов первого 5 и второго 6 регистров информация о величинах I

и I

поступает на первый и второй входы блока 9 вычитания соответственно. В блоке 9 формируется код, соответствующий разности I

- I

. Этот код через первый блок 10 деления, имеющий коэффициент деления, пропорциональный произведению ω_уд˙ H ˙ N, ω_уд- удельная максимальная влажность эталонного влажного образца, Н - его толщина, поступает на первый вход четвертого регистра 8. В регистре 8 запоминается код, соответствующий отношению
(I

-I

)/H .When the second frame sync pulse arrives at the synchronization input of block 12, at its output connected to the second input of the second register 6, a signal is generated according to which information about the value of I

is copied from the accumulating adder 4 to the second register 6, while the control signals at the outputs of block 12 connected to the control inputs of the analog-to-digital converter 2 and the accumulating adder 4, respectively, are absent. From the outputs of the first 5 and second 6 registers, information on the values of I

and I

arrives at the first and second inputs of the subtraction block 9, respectively. In block 9, a code is generated corresponding to the difference I

- I

. This code through the first block 10 division, having a division coefficient proportional to the product ω _beats ˙ H ˙ N, ω _beats is the specific maximum humidity of the reference wet sample, N is its thickness, is fed to the first input of the fourth register 8. The code is stored in register 8, appropriate relation
(I

-I

) / H.

-I)/(I

-I

)×ω_уд×H×N= (I

-I)/(T

T

)×ω_уд×H .According to the outputs of the control unit 12, connected to the control inputs of the registers 7 and 8, respectively, the recorded information comes from the outputs of the registers 7 and 8 to the first and second inputs of the second division unit 11, respectively. At the output of block 11, a code is generated proportional to the ratio
(I

-I) / (I

-I

) × ω _beats × H × N = (I

-I) / (T

T

) × ω _beats × H.

 This code corresponds to the value, which is an indicator of the moisture content of the test product. The calculated humidity value is displayed on indicator 13.

 Thus, the proposed structure and principle of operation of a thermal imaging moisture meter provide moisture control of porous materials and products with high accuracy, due to the possibility of taking into account temperature, humidity and air velocity. (56) PC application? N WO 87/04949, cl. G 01 N 25/62, 1987.

Claims (1)

 THERMAL VISION HUMIDOMETER containing a thermal imager, an analog-to-digital converter, a computing device and an indicator, characterized in that, in order to improve accuracy, the computing device contains an accumulating adder, four memory registers, two division blocks, a subtraction unit, a control unit with a synchronization system , with a three-position switch "Standard - measurement" and a start button, and the synchronization outputs of the thermal imager are connected to the synchronization inputs of the control unit, the outputs to connected to the control input of the analog-to-digital converter, the control input of the adder, the second inputs of the first and second registers, the control input of the subtraction unit and the control inputs of the third and fourth registers, respectively, the output of the analog-to-digital converter is connected to the input of the adder, the output of which is connected to the first inputs first and second registers, the outputs of which are connected respectively with the first and second inputs of the subtraction unit, the first and second outputs of which are connected respectively with the first input of the third register and through the first division block with the first input of the fourth register, the outputs of which are connected respectively to the first and second inputs of the second division block, the output of which is connected to the indicator input.

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