SU1422026A1 - Device for measuring characteristic time of heat transfer process - Google Patents

Abstract

The invention relates to thermal measurements. The aim of the invention is to expand the functionality of the device. A pulsed heat source 1 heats the sample. The sensor for the start of pulse heating of 2 expres- sions & A signal starts that goes to the R-input of the RS flip-flop 14, the output signal of which allows the passage of counting pulses through the circuit 16. The temperature meter 3 registers the temperature rise. on the sample side opposite to heat. The output signal of the temperature meter 3 (U) is fed to the inputs of amplifiers 4 and 7 of the main and additional channels, passes through the differentiators 5 and 8 of each channel to the inputs of extremators 6 and 9. Depending on the amplitude-time parameters of the signal Ug, the Stop signal is formed in one from the channels and through the OR circuit 13 is fed to the S input of the trigger 14, the output signal of which, after the arrival of the Stop signal, prohibits the passage of counting pulses from the generator 15 output through the AND 16 circuit to the input of the counter 17. The meter readings correspond to characteristic time of the heat transfer process and recorded on the indicator 18. 3 Il. W (L

Description

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The pitch of the signal after differentiation of the NIN Vg will already be inversely proportional to the square of the sample thickness (Fig. 26). Accuracy of the signal generation Stop extremator, corresponding to the moment b, is determined by the magnitude of the signal-to-noise ratio after the differentiator. The maximum value of this ratio, and consequently the accuracy of the extremator operation, is achieved for signals (samples) for which the condition

1 ,, j

I.

 L

where si is the upper limit frequency of the differentiator.

Therefore, to expand the range of measured characteristic times with high accuracy (for example, with increasing sample thickness), it is necessary to introduce additional detection channels, similar to the main one, for which condition (1) is fulfilled.

Because every extra

15

Q

The fundamental channel allows measurement of the characteristic time in the range of 20-100 ms. The introduction of additional channels and their combination in the device allows extending the range of measured characteristic times to 600 ms (for two additional channels) and up to 1.8 s (for three additional channels).

Thus, the combination of the proposed additional channels and their combination in the device allows us to expand the range of measured characteristic times, the range of controlled materials and the range of sample thicknesses.

Claims (1)

Formula invention thirty A device for measuring the characteristic time of the heat transfer process, comprising a pulsed heat source connected in series by a temperature meter, Wuxi the channel introduced to measure large. Litel, differentiator and extremator, values (large specimen thicknesses), takes the signal Vg - y, then it must be amplified, and the greater the sc, the greater must be the amplification of this signal in the channel. After passing the signal Vg (L through the differentiator of the main channel (Fig. 26, curve 23), the Stop signal is formed by the extremator of this channel. In all other channels, the signal Vg (L,) at the output of the differentiator is limited in amplitude (Fig. 2c, d , curves 24, 25) due to the greater amplification of the signal Vg, but the formed signals of the stop extremators of additional channels (operative | reliable signals of the stop) are blocked by the schemes AND of additional channels. 40 45 50 consisting of a second differentiator and a zero-organ, an RS trigger and a time interval meter containing a sensor for the start of a heating pulse and a series-connected generator, circuit I, a counter and an indicator, with the output of the sensor for the start of a heating pulse connected to the R input of the RS trigger, output The RS flip-flop is associated with the second input of the AND circuit, characterized in that, in order to expand the functionality, N channels are introduced into the device, each of which contains an amplifier, a differentiator and an extremator connected in series, a computer RATOR, the first input of which is connected to the output of the differentiator, RS channel trigger, the R input of which is connected to the output of the comV signal passing through the Vg signal from the parapair, the AND circuit, the first input of which is more than the maximum connected with the output of the extremator, and the second with the output of the RS flip-flop, which value (L) of the main channel, the extremator of the main channel will not be able to generate a Stop signal. | H : ala, with the outputs of the circuit AND each of N channels and the output of the first extre0 five 0 consisting of a second differentiator and a zero-organ, an RS trigger and a time interval meter containing a sensor for the start of a heating pulse and a series-connected generator, circuit I, a counter and an indicator, with the output of the sensor for the start of a heating pulse connected to the R input of the RS trigger, output The RS flip-flop is associated with the second input of the AND circuit, characterized in that, in order to expand the functionality, N channels are introduced into the device, each of which contains an amplifier, a differentiator and an extremator connected in series, a computer Rator, the first input of which is connected to the output of the differentiator, RS channel trigger, the R input of which is connected to the output of the com | N : ala, with the outputs of the circuit AND each of N channels and the output of the first ext. ; ffi / ) 27 b) t) urobeni  about rchnacheni. The second is an additional / nest. kina / 1 Freak out Osnodna. tnm 25 Urobeni restrictions First Dopo / 1nite / 1n Kan / 28 wik Ji L ig.2