IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0446416
(2007-10-26)
|
등록번호 |
US-8181516
(2012-05-22)
|
우선권정보 |
FR-06 09413 (2006-10-26); FR-07 54463 (2007-04-13) |
국제출원번호 |
PCT/EP2007/061517
(2007-10-26)
|
§371/§102 date |
20090420
(20090420)
|
국제공개번호 |
WO2008/049913
(2008-05-02)
|
발명자
/ 주소 |
|
출원인 / 주소 |
- Inergy Automotive Systems Research (Societe Anonyme)
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
3 인용 특허 :
5 |
초록
▼
Process for measuring a liquid level in a tank and a system suitable for such process that consists in: positioning, in the tank, two substantially identical reference capacitors and two substantially identical measurement capacitors so that, when the tank is full, the four capacitors are submerged
Process for measuring a liquid level in a tank and a system suitable for such process that consists in: positioning, in the tank, two substantially identical reference capacitors and two substantially identical measurement capacitors so that, when the tank is full, the four capacitors are submerged and so that, when the liquid level in the tank falls, a measurement capacitor/reference capacitor pair (Cmeas2, Cref2) emerges before another pair of capacitors (Cmeas1, Cref1);measuring the four capacitors Cmeas1, Cref1, Cmeas2, Cref2 in air when they are in air; andwhen at least one capacitor is at least partly immersed in the liquid, measuring the value of the four capacitors, and calculating the liquid level in the tank from the measured value of the capacitor partly immersed in the liquid, its value previously measured in air, and the measured values of the other capacitors.
대표청구항
▼
1. A process for measuring a liquid level in a tank that consists in: positioning, in the tank, two reference capacitors that are substantially identical and two measurement capacitors that are also substantially identical in such a way that, when the tank is full, the 4 capacitors are submerged and
1. A process for measuring a liquid level in a tank that consists in: positioning, in the tank, two reference capacitors that are substantially identical and two measurement capacitors that are also substantially identical in such a way that, when the tank is full, the 4 capacitors are submerged and that, when the liquid level in the tank falls, a measurement capacitor/reference capacitor pair (Cmeas2, Cref2) emerges before another pair of capacitors (Cmeas1, Cref1);when the 4 capacitors Cmeas1, Cref1, Cmeas2, Cref2 are in air, measuring the 4 capacitors in air; andwhen at least one capacitor is at least partly immersed in the liquid, measuring the value of said capacitor, measuring the values of the other capacitors and calculating the liquid level in the tank from the measured value of the capacitor partly immersed in the liquid, the value in air measured previously of the capacitor partly immersed in the liquid and the measured values of the other capacitors. 2. The measurement process according to claim 1, where the values in air of the reference and the measurement capacitors Cref1Air, Cref2Air, Cmeas1Air, Cmeas2Air have been measured and stored in the memory of an evaluation unit, said capacitors being positioned in the tank so as to cover the entire height of the tank continuously and so that, when the liquid level in the tank falls, these capacitors begin respectively to emerge at the maximum fill height of the tank lev4max for Cref2 and at levels lev3max for Cmeas2, lev2max for Cmeas1 and lev1max for Cref1 with lev4max>lev3max>lev2max>lev1max, said process using the evaluation unit to carry out the following steps: a) measuring the value of all the capacitors Cref1, Cref2, Cmeas1, Cmeas2 and evaluating which are completely in air by comparison in pairs: Cref2 with Cref1 and Cmeas2 with Cmeas1;b) calculating the liquid level in the tank from the following formulae: lev1=K1×(Cref1−Cref2) when only the first reference capacitor is at least partly immersed in the liquid; lev2=lev1max+K2×(Cmeas1-Cmeas2)(Cref1-Cref2) when the first reference capacitor is submerged and the first measurement capacitor is, in addition, at least partly immersed in the liquid; lev3=lev2max+K3×(Cmeas2-Cmeas1Air)(Cref1-Cref2) when the first reference capacitor and the first measurement capacitor are submerged and the second measurement capacitor is, in addition, at least partly immersed in the liquid; and lev4=lev3max+K4×(Cref2−Cref1Air) when the first reference capacitor, the first measurement capacitor and the second measurement capacitor are submerged and the second reference capacitor is, in addition, at least partly immersed in the liquid, K1, K2, K3 and K4 being proportionality coefficients that depend on the geometry of the capacitive gauge and Cmeas1Air and Cref1Air being the values of Cmeas1 and Cref1 effectively measured when these have been completely exposed to the air; and c) replacing, in the memory, the values of the capacitors in air stored previously with their measured value, where appropriate. 3. A system for measuring a liquid level in a tank suitable for a process according to claim 1, the system comprising: a capacitive gauge with a first measurement capacitor (Cmeas1) and a first reference capacitor (Cref1); andan evaluation unit connected to the capacitive gauge with a calculation means for calculating the liquid level based on signals coming from the capacitive gauge, wherein the capacitive gauge comprises, in addition, a second measurement capacitor (Cmeas2) substantially identical to Cmeas1 and a second reference capacitor (Cref2) substantially identical to Cref1. 4. The measurement system according to claim 3, in which the capacitive gauge comprises a support with a first end and a second end, the various capacitors being positioned on the support in the following order, going from the first end towards the second end: first reference capacitor (Cref1);first measurement capacitor (Cmeas1);second measurement capacitor (Cmeas2); andsecond reference capacitor (Cref2). 5. The measurement system according to claim 4, in which the various capacitors are positioned on the support symmetrically relative to a median line located between the first end and the second end. 6. The measurement system according to claim 3, in which the reference capacitors each cover a substantially smaller area than that which each of the measurement capacitors covers. 7. The measurement system according to claim 3, in which the measurement capacitors, or the reference capacitors, or both measurement and reference capacitors are formed by two interdigital electrodes. 8. The measurement system according to claim 7, comprising connection terminals to connect the measurement and reference capacitors to the evaluation unit. 9. The measurement system according to claim 3, in which the evaluation unit comprises a memory to temporarily store the values of the various capacitors measured in air.
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