Özet:

Analysis of the effect of pressures Pv of the sources of pure components, barometric pressure P0 and output pressure Pw in the gas-dynamic synthesizer on the component concentrations in the obtained mixtures has been carried out. In this regard, the use of typical pressure stabilizers in the synthesizer does not provide high accuracy of concentration of the prepared mixture components. It was shown that synthesizers designed on the basis of throttle flow summarizers are characterized by a significant effect of external pressures. Limit concentration deviation resulting from the changes in Pv, Pw and P0 measure (in % abs/kPa) 1; 0.6 and 0.03, respectively. It was established that equalizing of pressures at the ends of the dosing capillaries in the scheme of the flow summarizer leads, at least, to a partial compensation for the effect of external pressures. This is due to a unidirectional change in pressures and corresponding changes in the component flows metered by dosing capillaries. Full compensation for the effect of external pressures can be provided by choosing dimensions of the capillaries applying the obtained system of equations. Application of the dosing capillaries with dimensions differing from the calculated dimensions causes deviation of the component concentrations from the specified values at a level of 4 % rel. This deviation, if necessary, can be reduced by shortening capillary lengths during the measuring control of the synthesized mixture component concentrations using the gas analyzer. The synthesizer of binary (СО2+N2) and ternary (О2+СО2+N2) mixtures for calibration of analyzers of the blood gases was developed and studied. It was established that the limiting deviations of the component concentrations resulting from the effect of external pressures did not exceed 4·10-3 %/kPa and, therefore they can be neglected.Gas-dynamic synthesizers with a pressure equalizing scheme and the capillaries with dimensions determined by the compensation dependences are practically independent from the influence of external pressures and do not require high-precision means of their stabilization Author Biographies Ihor Dilay, Lviv Polytechnic National University Bandera str., 12, Lviv, Ukraine, 79013 Doctor of Technical Sciences, Associate Professor Department of Automation and Computer Integrated Technologies

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