FR2623289A1

FR2623289A1 - Principle for identifying the oxygen concentration which makes it possible to indicate the oxygen content of oxygen-enriched air

Info

Publication number: FR2623289A1
Application number: FR8715761A
Authority: FR
Inventors: Gerard O'kelly
Original assignee: TOLECTROMED SARL
Current assignee: TOLECTROMED SARL
Priority date: 1987-11-12
Filing date: 1987-11-12
Publication date: 1989-05-19

Abstract

Principle which makes it possible to identify the oxygen concentration of an oxygen-enriched air using a thermistor placed alternatively in ambient air and in enriched air for each identification and a calculating table previously read into an associated electronic intelligence which makes it possible to make comparisons and calculations in order to determine the percentage of oxygen contained in the enriched air.

Description

2 - DESCRIPTION
Principe d'identification de concentration d'oxygène permettant d'indiquer la teneur en oxygène d'air enrichi en oxygène.2 - DESCRIPTION
Oxygen concentration identification principle for indicating the oxygen content of oxygen enriched air.

L'appareil existant sur le marché utiZise comme principe d'identification une ceZZuZe combustible, qui a pour inconvénients d'avoir une durée de vie Zimitee, d'avoir recours à un étalonnage périodique et d'avoir un prix de revient élevé. The existing apparatus on the market uses as a principle of identification a fuel cell, which has the drawbacks of having a Zimite lifetime, of resorting to a periodic calibration and of having a high cost price.

Le principe seZon l'invention que nous mettons en oeuvre n'utilise qu'une seule thermistance, iZ permet de s'affranchir des variations de la tempdrature ambiante et de déterminer la teneur en oxygène d'un air enrichi en oxygène en comparant l'air ambiant, qui sert de référence, a Z'air enrichi à identifier, au moyen d'une table de calcul (fig 1) mise en mémoire dans une inteZZigence éZectronique associée (exemple :
Microprocesseur).The principle according to the invention that we implement uses only one thermistor, iZ makes it possible to overcome variations in the ambient temperature and to determine the oxygen content of an air enriched with oxygen by comparing the ambient air, which serves as a reference, has Z'air enriched to identify, by means of a calculation table (FIG. 1) stored in an associated electronic interlock (example:
Microprocessor).

Pour chaque identification, la thermistance est d'abord placée dans Z'air ambiant pendant un temps trèe court, immédiatement après, elle est mise en présence de Z'air enrichi à identifier ; la variation de tension enregistrée entre les deux opérations est traitée par la table de calcul (fig 1) préalablement mise en mémoire. For each identification, the thermistor is first placed in the ambient air for a very short time, immediately afterwards, it is put in the presence of enriched Z'air to identify; the voltage variation recorded between the two operations is processed by the calculation table (FIG. 1) previously stored in memory.

Etablissement de la table de calcul (fig 1). Establishment of the calculation table (fig 1).

Nous avons, sous une température ambiante, A, et un courant constant, x, traversant la thermistance,mis cette thermistance en présence de l'air ambiant, E, pour obtenir un point de référence, P,. Puis la thermistance a été mise en présence d'air enrichi en oxygène, F, G, H, à x% d'oxygène, y% d'oxy gAne et % d'oxygène. Nous avons obtenu les points 4 R, S, ceux-ci nous permettent d'obtenir la courbe T. We have, under ambient temperature, A, and a constant current, x, passing through the thermistor, put this thermistor in the presence of the ambient air, E, to obtain a reference point, P ,. Then the thermistor was placed in the presence of oxygen enriched air, F, G, H, x% oxygen, y% oxygen and% oxygen. We got the points 4 R, S, these allow us to get the curve T.

En conversant les memes paramètres : air ambiant, E, courant constant, x, traversant la t@ermistance, air enrichi,
F, G, H, le procédé a été renouvelé pour des températures,
B, C, D, afin d'obtenir d'autres points, tels.: P1, Q1 R1, S1, donnant la courbe, U ;, P2 Q2 R2 S2 donnant la courbe, V,;
P3, Q3, R3 S3, donnant la courbe, w. On constate que quelque soit la température à ZaqueZZe Zes essais sont effectués, Zes écarts, M, N, O, restent constants.By conversing the same parameters: ambient air, E, constant current, x, crossing the constant, enriched air,
F, G, H, the process was renewed for temperatures,
B, C, D, to obtain other points, such as: P1, Q1 R1, S1, giving the curve, U; P2 Q2 R2 S2 giving the curve, V ,;
P3, Q3, R3 S3, giving the curve, w. It is found that whatever the temperature at ZaqueZZe Zes tests are made, Zes deviations, M, N, O, remain constant.

Nota . Tous ces points de mesure sont donnés a titre d'exem- ple et ne sont en aucun cas Zimitatifs. Note. All these measuring points are given as examples and are not in any way Zimitatives.

L'intelligence électronique associée ne tient pas compte des variations, I, J, K, L, et ne considère que Zes écarts de variation, M, N, O, dont la partioularité est de rester constante. The associated electronic intelligence does not take into account the variations, I, J, K, L, and considers only Zes variations of variation, M, N, O, whose partioularité is to remain constant.

Lors d'une identification, la variation de tension définie par la différence entre air ambiant et air enrichi en oxygène est comparée et traitée par l'intermédiaire de la tabZe de calcul comme dans- l'exemple (fig 2). La thermistance dans l'air ambiant, E1, donne le point d'étalonnege, PE, qui devient la référence, ensuite la thermistance est mise en présence de Z'air enrichi à identifier, ceci donne le point,
P.I, c'est la différence, Y, entre, PI, et, PE > qui est comparée et tr@itée par la table de calcul et donne le pourcentage d'oxygène contenu dans Z'air enrichi. During identification, the voltage variation defined by the difference between ambient air and oxygen-enriched air is compared and processed via the calculation table as in the example (FIG. 2). The thermistor in the ambient air, E1, gives the calibration point, PE, which becomes the reference, then the thermistor is put in the presence of enriched Z'air to identify, this gives the point,
PI, it is the difference, Y, between, PI, and PE> which is compared and tr @ itée by the table of computation and gives the percentage of oxygen contained in Z'air enriched.

Claims

l) Oxygen concentration identification principle, to indicate the oxygen content of an oxygen enriched cir, characterized in that iZ only requires a thermistor and a calculation table stored in an electronic intelligence associated, allowing to perform calculations.

2) Principle seZon claim N 1 characterized in that for each identification iZ must first put the thermistor in the air. ambient to record Ze reference point and then put the thermistor in the presence of Z'air enriched with oxygen to be identified.

3) Principle seZon claim N 1 characterized in that a computation table established according to common data (fig 1) is préaZabZement stored in an associated electronic interzérence.

4) Principle according to the claims N 1, N 8 and N 3, characterized in that Zes known data recorded in the calculation table in the associated Z'inteZZigence electronic memory are compared with the data recorded in reference point and Zes recorded data in the oxygen-enriched air space to be identified, to calculate, after calculation, the percentage of oxygen contained in the enriched air space.