Capacitive pressure sensor
AssigneeDynisco Instruments LLC
InventorsLeo E. Barron, John A. Czazasty
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Abstract
High temperature pressure sensing devices and methods are disclosed. In some embodiments, a high temperature pressure sensor including intrinsic zero output and span correction versus temperature is disclosed. In addition, ways in which to improve high temperature performance through the use of intermediate circuits located towards the distal end of the high temperature pressure sensor as well as configurations to reduce thermally induced stresses within the pressure sensor are disclosed. The disclosed embodiments also detail ways in which to reduce signal loss due to various stray capacitances within the pressure sensor to improve signal fidelity and sensitivity.
Claims20
A pressure sensor, comprising:
- a probe body;
- a capacitive sensor disposed at a distal end of the probe body, the capacitive sensor producing a sensing capacitance;
- a shunt capacitance;
- and
- wherein a change in the sensing capacitance resulting from a change in temperature is offset by a corresponding change in the shunt capacitance.
A method of making a pressure sensor, comprising:
- arranging a pressure deflectable diaphragm cap having a first capacitive surface on a probe body;
- electrically coupling the first capacitive surface to the probe body;
- selecting a material having a desired dielectric constant and forming a non-deformable component from the material;
- forming a second capacitive surface on a portion of the non-deformable component;
- connecting a lead to the second capacitive surface and positioning the non-deformable component within the probe body wherein a shunt capacitance is defined between the lead and the probe body;
- and
- arranging the non-deformable component relative to the pressure deflectable diaphragm cap by spacing the second capacitive surface away from the first capacitive surface such that the first and second surfaces define a capacitive sensor having a sensing capacitance, wherein a change in the sensing capacitance resulting from a change in temperature is offset by a corresponding change in the shunt capacitance.
Dependencies are inferred from the claim text.