Industrial pressure sensor having enhanced dielectric fill fluid
First Claim
1. A capacitance-based pressure sensor comprising:
- a housing comprising;
an interior cavity within the housing; and
a channel extending from an exterior of the housing to the interior cavity;
a sensing diaphragm disposed within the interior cavity;
an electrode disposed within the interior cavity opposing the sensing diaphragm; and
a fill fluid occupying the interior cavity such that a pressure from the channel is conveyed to the sensing diaphragm to adjust a capacitance between the electrode and the sensing diaphragm;
wherein the fill fluid has a dielectric constant greater than about 3.5.
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Accused Products
Abstract
A capacitive pressure sensor for an industrial process transmitters comprises a housing, a sensing diaphragm, an electrode and a fill fluid. The housing includes an interior cavity and a channel extending from an exterior of the housing to the cavity. The sensing diaphragm is disposed within the interior cavity opposite the electrode. The fill fluid occupies the interior cavity such that a pressure from the channel is conveyed to the sensing diaphragm to adjust a capacitance between the electrode and the sensing diaphragm. The fill fluid has a dielectric constant higher than about 3.5. In various embodiments, the pressure sensor has a diameter less than approximately 3.175 centimeters (˜1.25 inches), the electrode has a diameter less than approximately 1 cm (˜0.4 inches), the pressure sensor has a capacitance of approximately 5 to approximately 10 pico-farads, and the fill fluid is comprised of hydraulic fluid having a liquid additive.
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Citations
27 Claims
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1. A capacitance-based pressure sensor comprising:
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a housing comprising; an interior cavity within the housing; and a channel extending from an exterior of the housing to the interior cavity; a sensing diaphragm disposed within the interior cavity; an electrode disposed within the interior cavity opposing the sensing diaphragm; and a fill fluid occupying the interior cavity such that a pressure from the channel is conveyed to the sensing diaphragm to adjust a capacitance between the electrode and the sensing diaphragm; wherein the fill fluid has a dielectric constant greater than about 3.5. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A pressure sensor comprising:
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a cell body comprising; an interior cavity; a sensing diaphragm disposed within the interior cavity to divide the interior cavity into first and second chambers; a first interior surface within the first chamber facing the sensing diaphragm; and a second interior surface within the second chamber facing the sensing diaphragm; a first electrode disposed on the first interior surface to form a first capacitor with the sensing diaphragm; a second electrode disposed on the second interior surface to form a second capacitor with the sensing diaphragm; a fill fluid disposed within the first and second chambers, the fill fluid being adapted to receive pressures to adjust the position of the sensing diaphragm and change the capacitances of the first and second capacitors; and wherein the fill fluid has a dielectric constant greater than about 3.5. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A pressure transmitter for measuring a pressure of a process fluid, the pressure transmitter comprising:
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a transmitter housing; a capacitance-based pressure sensor for sensing the pressure of the process fluid, wherein the pressure sensor; is disposed within the housing; comprises a cell body having a diameter less than approximately 3.175 centimeters (˜
1.25 inches); andhas a capacitance in the range of is approximately five to approximately ten pico-farads; a hydraulic relay system comprising; an isolation diaphragm positioned on an exterior of the transmitter housing; and an isolation tube extending from the pressure sensor to the isolation diaphragm; a pressure sensor fill fluid situated within the hydraulic relay system and comprising a high-dielectric constant liquid fluid selected from the group consisting of; isopropyl alcohol, acetone, ethylene glycol and glycerin; and transmitter electronics positioned within the housing, the transmitter electronics configured to receive and condition pressure signals from the pressure sensor. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification