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Capative Differential Pressure sensor for Harsh Environment

Abstract

A capacitive differential pressure sensor for the pressure range of 0–1 bar has been developed. The primary field of application is hydrodynamic flow measurements in hot petroleum wells. In these harsh environments the sensor has to survive high common mode pressure in the range of 1000 bar and temperatures up to 180°C. The pressure element is formed in a triple-stack of fusion-bonded silicon wafers. A bossed diaphragm etched in the upper wafer bends due to the differential pressure across it. The capacitance to the middle wafer is measured. A reference capacitor insensitive to the differential pressure enables compensation for capacitance shifts caused by ambient pressure and temperature changes. The lower silicon wafer is included to minimise the diaphragm stress from the package. An ASIC, certified for 230°C, which is developed at SINTEF, is used for signal read-out.The sensor is measured to have a low zero pressure signal drift, smaller than 2.5% of full-scale output, when the temperature is varied in the range 0–200°C and the ambient pressure in the range 0–1000 bar. The sensitivity of the sensor is sufficient for the application

Category

Academic article

Language

English

Author(s)

  • Sigurd T. Moe
  • Kari Schjølberg-Henriksen
  • Dag Thorstein Wang
  • E Lund
  • J Nysæther
  • Liv Furuberg
  • Maaike Margrete Visser Taklo
  • Truls Fallet
  • R W Bernstein

Affiliation

  • SINTEF Digital / Microsystems and Nanotechnology

Year

2000

Published in

Sensors and Actuators A-Physical

ISSN

0924-4247

Volume

83

Issue

1-3

Page(s)

30 - 33

View this publication at Cristin