Resonant frequency based pressure sensor
First Claim
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1. A pressure sensor for sensing a pressure of a process fluid, comprising:
- a deformable sensor body exposed to the pressure of the process fluid and having a cavity formed therein which receives a differential pressure, wherein the sensor body deforms in response to a line pressure;
a diaphragm suspended in the cavity of the sensor body and having a tension which changes in response to deformation of the sensor body, the diaphragm flexing in response to the differential pressure;
a resonant frequency sensor configured to sense a resonant frequency of the diaphragm, the resonant frequency indicative of the line pressure of the process fluid; and
a deflection sensor configured to sense deflection of the diaphragm which is indicative of the differential pressure.
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Abstract
A pressure sensor for sensing a pressure of a process fluid includes a sensor body exposed to the pressure of the process fluid. The sensor body deforms in response to the pressure. A diaphragm suspended from the sensor body has a tension which changes in response to deformation of the sensor body. A resonate frequency of the diaphragm is measured. The measured resonant frequency is indicative of the line pressure of the process fluid and integrity of the isolation fill fluid system. In addition to measuring the resonant frequency, the oscillation mode itself can be used as a diagnostic tool to assess sensor health.
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Citations
19 Claims
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1. A pressure sensor for sensing a pressure of a process fluid, comprising:
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a deformable sensor body exposed to the pressure of the process fluid and having a cavity formed therein which receives a differential pressure, wherein the sensor body deforms in response to a line pressure; a diaphragm suspended in the cavity of the sensor body and having a tension which changes in response to deformation of the sensor body, the diaphragm flexing in response to the differential pressure; a resonant frequency sensor configured to sense a resonant frequency of the diaphragm, the resonant frequency indicative of the line pressure of the process fluid; and a deflection sensor configured to sense deflection of the diaphragm which is indicative of the differential pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A process control transmitter including transmitter circuitry coupled to a pressure sensor for sensing a pressure of a process fluid, comprising:
- a deformable sensor body exposed to the pressure of the process fluid and having a cavity formed therein which receives a differential pressure, wherein the sensor body deforms in response to a line pressure;
a diaphragm suspended in the cavity of the sensor body and having a tension which changes in response to deformation of the sensor body, the diaphragm flexing in response to the differential pressure;
a resonant frequency sensor configured to sense a resonant frequency of the diaphragm, the resonant frequency indicative of the line pressure of the process fluid; and
a deflection sensor configured to sense deflection of the diaphragm which is indicative of the differential pressure. - View Dependent Claims (12)
- a deformable sensor body exposed to the pressure of the process fluid and having a cavity formed therein which receives a differential pressure, wherein the sensor body deforms in response to a line pressure;
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13. A method of sensing pressure of a process fluid, comprising:
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applying a differential pressure of the process fluid to a cavity formed in a sensor body and thereby deforming the sensor body in response to a line pressure; suspending a diaphragm in the cavity, the diaphragm having a tension which changes in response to deformation of the sensor body, the diaphragm further deflecting in respond to the differential pressure; sensing a resonant frequency of the diaphragm, the resonant frequency indicative of the line pressure of the process fluid; sensing deflection of the diaphragm indicative of the differential pressure; providing a line pressure output indicative of line pressure of process fluid based upon sensed resonant frequency of the diaphragm; and providing a differential pressure output indicative of the differential pressure based upon the sensed deflection of the diaphragm. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification