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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. 14 figs.
Inventors:
Issue Date:
OSTI Identifier:
119054
Assignee:
Cornell Research Foundation, Inc., Ithaca, NY (United States) PTO; SCA: 440800; PA: EDB-95:150470; SN: 95001477075
Patent Number(s):
US 5,459,406/A/
Application Number:
PAN: 8-266,331
Contract Number:
AC22-91PC90183
Resource Relation:
Other Information: PBD: 17 Oct 1995
Research Org:
Cornell University
Country of Publication:
United States
Language:
English
Subject:
44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; SUSPENSIONS; FLUID FLOW; ELECTRIC PROBES; DESIGN; PARTICULATES; SPATIAL DISTRIBUTION; TWO-PHASE FLOW; FLOWMETERS