Differential pressure measuring apparatus
First Claim
1. Differential pressure measuring apparatus comprising a single chamber differential pressure sensor which comprises two resilient sensor diaphragms enclosing a volume filled with a fluid and in which two measuring capacitors are formed whose capacitances vary in opposite senses as a function of the sensor differential pressure which results from the pressures acting on the two sensor diaphragms, and further comprising an evaluation circuit which calculates the sensor differential pressure from the capacitances of the measuring capacitors and comprises a first compensation arrangement which compensates the influences of the sensor temperature and of sensor parameters on the calculated sensor differential pressure, the single chamber differential pressure sensor being connected with at least one adaptor comprising a volume filled with a fluid, which is closed on the one hand by one of the two sensor diaphragms and on the other hand by a resilient adaptor diaphragm, and the evaluation circuit comprising a further compensation arrangement for each adaptor, which compensates the influences of the adaptor temperature and of adaptor parameters on the sensor differential pressure corrected by the first compensation arrangement.
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Abstract
The differential pressure measuring apparatus comprises a single chamber differential pressure sensor having two resilient sensor diaphragms which enclose a volume filled with a fluid. In the single chamber differential pressure sensor two measuring capacitors are formed whose capacitances vary in opposite senses in response to the sensor differential pressure between the pressures acting on the two sensor diaphragms. The single chamber differential pressure sensor is connected to an adaptor comprising a volume filled with a fluid which is closed on the one hand by one of the two sensor diaphragms and on the other hand by an elastic adaptor diaphragm. An evaluation circuit calculates the sensor differential pressure from the capacitances of the measuring capacitors. The evaluation circuit comprises a first compensation arrangment which compensates the influences of the sensor temperature and of the sensor parameters on the calculated sensor differential pressure, and a second compensation arrangement which compensates the influences of the adaptor temperature and of the adaptor parameters on the sensor differential pressure corrected by the first compensation arrangement.
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Citations
3 Claims
- 1. Differential pressure measuring apparatus comprising a single chamber differential pressure sensor which comprises two resilient sensor diaphragms enclosing a volume filled with a fluid and in which two measuring capacitors are formed whose capacitances vary in opposite senses as a function of the sensor differential pressure which results from the pressures acting on the two sensor diaphragms, and further comprising an evaluation circuit which calculates the sensor differential pressure from the capacitances of the measuring capacitors and comprises a first compensation arrangement which compensates the influences of the sensor temperature and of sensor parameters on the calculated sensor differential pressure, the single chamber differential pressure sensor being connected with at least one adaptor comprising a volume filled with a fluid, which is closed on the one hand by one of the two sensor diaphragms and on the other hand by a resilient adaptor diaphragm, and the evaluation circuit comprising a further compensation arrangement for each adaptor, which compensates the influences of the adaptor temperature and of adaptor parameters on the sensor differential pressure corrected by the first compensation arrangement.
Specification