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Title: Guarded capacitance probes for measuring particle concentration and flow

Guarded capacitance probe structures are constructed with guard electrodes surrounding one or more sensor electrodes and ground electrodes or grounded surfaces surrounding the guard electrodes. In a one sensor embodiment, the probe utilizes an apertured sensor electrode and the guard electrode both surrounds the sensor electrode and fills the aperture. This embodiment is particularly useful for measuring particle concentration in a fluid suspension contained within a vessel or pipe. The portion of the guard electrode within the aperture of the sensor electrode prevents electric field lines from emanating from the sensor electrode into the fluid suspension and toward infinity. A two sensor embodiment of the probe is useful for measuring flow velocities of fluid suspensions through cross correlation of the outputs generated by each sensor. The relative dimensions of the guard and sensor electrodes are selected to provide the most accurate measurements by confining the electric lines emanating from the sensor electrode or electrodes and terminating on the surrounding grounded surfaces to a small measurement volume of the fluid suspension near the vessel or pipe wall.
Inventors:
 [1]
  1. (Ithaca, NY)
Issue Date:
OSTI Identifier:
870563
Assignee:
Cornell Research Foundation, Inc. (Ithaca, NY) NETL
Patent Number(s):
US 5546006
Contract Number:
AC22-91PC90183
Research Org:
CORNELL UNIVERSITY
Country of Publication:
United States
Language:
English
Subject:
guarded; capacitance; probes; measuring; particle; concentration; flow; probe; structures; constructed; guard; electrodes; surrounding; sensor; ground; grounded; surfaces; embodiment; utilizes; apertured; electrode; surrounds; fills; aperture; particularly; useful; fluid; suspension; contained; vessel; pipe; portion; prevents; electric; field; lines; emanating; infinity; velocities; suspensions; correlation; outputs; generated; relative; dimensions; selected; provide; accurate; measurements; confining; terminating; measurement; volume; near; wall; accurate measurements; flow velocities; probe utilizes; guard electrode; sensor electrode; field lines; electric field; particularly useful; ground electrode; particle concentration; measuring particle; accurate measurement; surrounding grounded; surfaces surrounding; capacitance probe; prevents electric; outputs generated; measuring flow; sensor electrodes; guarded capacitance; guard electrodes; grounded surfaces; pipe wall; ground electrodes; electrodes surrounding; accurate measure; surrounding ground; rate measurements; capacitance probes; probe structures; /324/361/