SU1408251A1 - Device for measuring index of thermal lag of thermal converter - Google Patents

Abstract

The invention relates to the field of heat engineering measurements. Target 1 of the invention is the measurement accuracy measurement. At the time of submission of the temetururian jump, pa of sample 1 and the investigated 2 thermal converters on b. In the 15th direction from the thermal converter, a signal is received that is triggered by closing the circuit of the control unit — thermal converters — electrically conductive measurement medium — ground at 1 pip. The control unit 15 closes the keys 7 and 11 for the passage of pulses from the generator 8 onopHoii frequency to the counters 9 p 12 pmpu.chsov. In the latter, a certain number of gms are fixed, respectively equal to the numbers N, and Nj. In block 13, the division of the number N. is carried out. Pa number N, and the number N is formed at its output, the value of which is proportional to the thermal inertia index of the thermocouple under study 2. 1 Il. (C (f. C

Description

The invention relates to the field of heat engineering measurements and can be used when measuring the heat inertia indicator of thermal converters in laboratory and plant conditions.

The purpose of the invention is to improve the measurement accuracy by reducing the effect on the measurement result of changes in the parameters of the device's elements.

The drawing shows the block diagram of the proposed device.

The device contains exemplary 1 and 2 thermocouples of the same type under study, the outputs of which are connected to the inputs of the first 3 and second 4 amplifiers, two comparison circuits 5 and 6, the first switch 7, the reference frequency generator 8, the first count 4k 9 pulses , tunable frequency divider 1C, second switch 11, second count 4VK 12 pulses, dividing unit 13, reference voltage source 14 and control unit 15 hk.

The device works as follows obra3QM.

When applying simultaneously a temperature jump to the model 1 and the studied 2

go

thermal converters their output signals

of

and

vary according to the law t) UK + (UO-U «) - e-r,;

IU2 (t) Ux-f () -e-%,

rd; ё and „u U are the values of the output signals of 30 thermocouples at the initial and final temperature; tours, respectively;

: t, U Tj - indicators of thermal inertia of the model and the studied

The division factor K of the tunable frequency divider 10 is chosen so as to establish the required proportionality between the number N and the measured index of thermal inertia c.

Claims (1)

Invention Formula A device for measuring the thermal inertia index of a thermocouple containing sample and thermocouple under study, the outputs of which are connected to the inputs of the first and thermocouples of the respective 35 second amplifiers, the first and second circuits the following number of pulses is recorded in each counter: „OrJJx M with. F, - | Mr. JL  - ЧЦ J., I (Jon to N, Vfn ( f ;; ,  "- g g f N 7G where f (and fj are the frequencies of the pulses arriving at the inputs of counters 9 and 12, respectively, from the output of the generator 8 and from the output of the tunable frequency divider 10. The dividing unit 13 divides the number Nj by the number N, with the result that the number N is formed at its output, the value of which is proportional to the thermal inertia indicator of the thermal converter under study. N-i.-1 N / 4, f, where k is the division factor of the 10 frequency divider. The signal from the output of the divider 13 is fed to the input of the digital display unit, where it is displayed on the digital indicator. The division factor K of the tunable frequency divider 10 is chosen so as to establish the required proportionality between the number N and the measured index of thermal inertia c. Invention Formula A device for measuring the thermal inertia index of a thermocouple containing sample and thermocouple under study, the outputs of which are connected to the inputs of the first and  second amplifiers, the first and second circuits stately. The voltages C (t) and Uz. (T), preamplified in amplifiers 3 and 4, respectively, are fed to the inputs of circuits 5 and 6 of the comparison. At the moment when the temperature jump is applied, the trigger signal is received from the thermal converters to the control unit 15 by the model and thermal transformers under study. comparison, the first inputs of which are connected to the outputs of the respective amplifiers, the first pulse counter, the input of which through the first key is connected to the output 40 of the reference frequency generator, a digital display unit, characterized in that, in order to improve the measurement accuracy, a tunable frequency divider is inserted second key, second pulse counter, 6vlOK division, the source of the reference voltage and RB | which can be implemented by a control unit whose input is connected to the terminals (for example, by closing the circuit with block converters, and the output is connected to control - thermocouples 1 and 2 - electrical / electrically conductive measuring medium - earth5) women. The control unit closes the switches 7 and 11 for the passage of pulses from the HtipaTopa reference frequency to the counters 9 and 13 of the pulses. At times t, and t, the equalities of the stresses Ui (t) Uon and U2. (T) Uon, where Upn is the source voltage .14 of the reference 50 the first control inputs of both keys, the second control inputs of which are connected to the outputs of the first and second comparison circuits, the second inputs of which are connected to the output of the reference voltage source, while the second input of the key is connected via a tunable frequency divider to the reference frequency generator, and the output - with the entrance of the second counter Hs | springs, circuits 5 and 6 comparing the output of 55 pulses, the outputs of both counters with pulses of signals close the keys 7 and 11, and: counters 9 and 12 stop the counting of pulses. owls are connected, respectively, to the inputs of the dividing plate, the output of which is connected to the input of the digital display unit. comparison, the first inputs of which are connected to the outputs of the respective amplifiers, the first pulse counter, the input of which through the first key is connected to the output of the reference frequency generator, a digital display unit, characterized in that, in order to improve the measurement accuracy, a tunable frequency divider is inserted second key, second pulse counter, 6vlOK division, the source of the reference voltage and a control unit whose input is connected to thermal converters, and the output is connected to the first control inputs of both keys, the second control inputs of which are connected to the outputs of the first and second comparison circuits, the second inputs of which are connected to the output of the reference voltage source, while the second input of the key is connected via a tunable frequency divider to the reference frequency generator, and the output - with the entrance of the second counter pulses, the outputs of both pulse counters are connected respectively to the inputs of the dividing plate, the output of which is connected to the input of the digital display unit.