GB1017072A - Improvements relating to the analysis of alloys and the like - Google Patents

Abstract

1,017,072. Simulating networks. HILGER & WATTS Ltd. July 10, 1962 [July 10, 1961], No. 24955/61. Heading G4G. In a method of electrical analogue computation for determining the constituent proportions of alloying materials A1, A2 ... An in an alloy, the ratio values obtained from spectrographic readings of the ratios A1/B, A2/B ... An/B, where B is the base material of the alloy, are set up as parameters of a succession of elements in an electric circuit which contains a further element calibrated to represent a unity term, the whole circuit simulating the equation In the spectrographic analysis of an alloy, measurements are made over a given period of time of the average intensities of characteristic spectrum lines of the materials present, and using the measurement relating to the base material as a datum, the other measurements are expressed as ratios thereof. These ratios may be represented as potentiometer settings in a resistor chain energized from an adjustable source V (Fig. 1, not shown) the chain also including a fixed unity resistance. In operation the potentiometers are first set to zero and the voltage (V), which appears across the unity resistance, is adjusted to show a reading of say 100 v. on a meter connected across the resistance, so that thereafter voltages may be read off as percentages. When the potentiometers are set to their correct values R a , R b ... R n representing the ratios A1/ B &c., then where V1 is the voltage across the unity resistance. The arrangement thus simulates (in inverted form) the required equation, and since V has been set to 100 v., by measuring the voltage V 1 a direct percentage reading of the proportion of base material present is obtained. In the circuit of Fig. 2 the potentiometers 24a ... 24n are set according to the measured ratios and are arranged in parallel with one another and with a constant resistance 20 of equal value to the resistances 20a ... 20n, which are in the tapping arms of the potentiometer. A summation unit 22 adds the voltages produced by this parallel arrangement and feeds this voltage to a high gain amplifier 28, where it is first subtracted from a preset applied voltage V before amplification. Calibration is carried out by adjusting the applied voltage V with all the potentiometer tapping arms grounded until the voltage reading across the resistance 20 is unity. With the potentiometers correctly set, the output voltage of the amplifier 28 is If A is chosen very large then an equation of identical form to that given previously.