发明授权
- 专利标题: High output capacitative gas/liquid detector
- 专利标题(中): 高输出电容气体/液体检测器
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申请号: US09221636申请日: 1998-12-23
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公开(公告)号: US06212956B1公开(公告)日: 2001-04-10
- 发明人: David K. Donald , Leslie A. Field , Phillip W. Barth , Storrs T. Hoen
- 申请人: David K. Donald , Leslie A. Field , Phillip W. Barth , Storrs T. Hoen
- 主分类号: G01L912
- IPC分类号: G01L912
摘要:
A gas or liquid detector that includes a capacitative sensor and a capacitance detector. The capacitative sensor includes a first electrode and a second electrode separated from one another, and additionally includes Debye elements extant in the liquid adjacent such portions of the electrodes that are in contact with the liquid. The Debye elements each include a Debye capacitor with an associated shunt conductor. The shunt conductor has an exponentially-increasing conductance versus voltage characteristic. The Debye element adjacent the first electrode and the Debye element adjacent the second electrode are connected in series by conduction through the liquid. The Debye element adjacent at least the first electrode has a substantially greater capacitance than the capacitance between the electrodes absent the Debye elements. The capacitance detector is connected to the capacitative sensor and measures the capacitance of the capacitative sensor by applying an alternating voltage between the electrodes. The alternating voltage has a voltage amplitude less than the voltage amplitude at which the Debye element extant adjacent at least the first electrode ceases to be predominantly capacitative. By measuring the capacitance of the capacitative sensor using an alternating voltage having a voltage amplitude less than the voltage amplitude at which the Debye element ceases to be predominantly capacitative, the capacitances measured are one or more orders of magnitude greater than the capacitances conventionally measured between electrodes in contact with a liquid.