Differential capacitive pressure sensor with over-pressure protection and method of providing over-pressure protection to a capacitive pressure sensor

Capteur capacitif de pression différentielle avec protection contre la surpression et procédé pour la protection d'un capteur de pression capacitif contre la surpression

Kapazitiver Differenzdrucksensor mit Überdrucksicherung und Verfahren zur Überdrucksicherung eines kapazitiven Drucksensors

Abstract

A pressure sensor (10) having over-protection for use in environments which subject the sensor to large pressure overloads, such as may occur when such sensor is exposed to jet and automobile engine backfires, explosive gas furnace ignitions and similar high pressure events. Essentially two capacitive sensors are bonded together, diaphragm-to-­diaphragm, with the diaphragms (111A/111B) spaced but juxtaposed and forming a closed, reference cavity chamber (114) between them, along with a central, side, wall spacer (116C). The capacitance variation with differential pressure is measured between, the two diaphragms and with reference to their respective bases (112A/112B). Each of the diaphragms preferably is provided with a center bearing or stops (115A/115B) for accepting the load when over-pres­sured. When in contact at the center, the stiffness of the combined pair of diaphragms is increased several fold over that of a single diaphragm. Furthermore, providing for bottoming stops for the combination on either side of the sensor prevents deflection to the breaking point, because the presence of the opposed bottoming stops stiffens its respective diaphragm.

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Patent Citations (3)

    Publication numberPublication dateAssigneeTitle
    EP-0059488-A1September 08, 1982Hitachi, Ltd.Capacitive pressure sensor
    GB-2042258-ASeptember 17, 1980Nissan MotorPressure sensor
    US-4586109-AApril 29, 1986Bourns Instruments, Inc.Batch-process silicon capacitive pressure sensor

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Cited By (4)

    Publication numberPublication dateAssigneeTitle
    EP-0524550-A1January 27, 1993Fibronix Sensoren GmbHPalpeur de pression relative rempli de gaz
    EP-0611221-A1August 17, 1994Sextant Avionique S.A.Kapazitiver Microsensor mit geringer Fremdkapazitanz und Herstellungsverfahren
    FR-2701562-A1August 19, 1994Sextant AvioniqueMicro-capteur capacitif à faible capcité parasite et procédé de fabrication.
    WO-2005024370-A1March 17, 2005Auxitrol S.A.Protection d’une membrane deformable contre de fortes deformations dans une structure micromecanique