Capacitive pressure transmitter
AssigneeRosemount Inc.
InventorsDavid A. Broden, David A. Horky
Life of this patent
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Abstract
A capacitive pressure transmitter is provided. In one aspect, the transmitter includes a capacitive pressure sensor coupled directly to the measured media without any intervening fluid isolation. A filter is preferably used to keep particulates from reaching the measuring diaphragm. In another aspect, a capacitive pressure transmitter is provided with at least one self-contained isolator interposed between a process connection and the capacitive pressure sensor. In both aspects, the capacitive pressure transmitter is relatively small and preferably constructed from materials that facilitate low-cost manufacture.
Claims7
A capacitive pressure transmitter comprising:
- a capacitive pressure sensor including:
- a sensor body defining a chamber therein, the sensor body having a plurality of sensor inlets in fluidic communication with the chamber;
- a conductive deflectable diaphragm disposed in the chamber;
- at least one capacitive plate disposed in the chamber relative to the diaphragm such that diaphragm deflection generates a change in capacitance between the at least one plate and the diaphragm;
- and
- a non-conductive layer interposed between the at least one plate and the diaphragm;
- and
- a process media inlet operably coupled to one of the plurality of sensor inlets and adapted to couple to a source of process media to bring the process media into direct contact with the measuring diaphragm;
- a transmitter inlet operably coupled to the other of the plurality of sensor inlets;
- sensor circuitry coupled to the capacitive pressure sensor to generate a sensor signal based upon the capacitance of the capacitive pressure sensor;
- and
- transmitter circuitry coupled to the sensor circuitry to transmit information relative to the sensor signal over a process communication loop.
Dependencies are inferred from the claim text.