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Title: Capacitive proximity sensor

A proximity sensor based on a closed field circuit is disclosed. The circuit comprises a ring oscillator using a symmetrical array of plates that creates an oscillating displacement current. The displacement current varies as a function of the proximity of objects to the plate array. Preferably the plates are in the form of a group of three pair of symmetric plates having a common center, arranged in a hexagonal pattern with opposing plates linked as a pair. The sensor produces logic level pulses suitable for interfacing with a computer or process controller. The proximity sensor can be incorporated into a load cell, a differential pressure gauge, or a device for measuring the consistency of a characteristic of a material where a variation in the consistency causes the dielectric constant of the material to change. 14 figs.
Inventors:
Issue Date:
OSTI Identifier:
7183883
Assignee:
Dept. of Energy, Washington, DC (United States) PTO; EDB-94-103514
Patent Number(s):
US 5315884; A
Application Number:
PPN: US 7-756669
Contract Number:
AC09-89SR18035
Resource Relation:
Patent File Date: 9 Sep 1991
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; DISPLACEMENT GAGES; DESIGN; MEASURING INSTRUMENTS; POSITIONING; ELECTRIC CURRENTS; PRESSURE GAGES; PROCESS COMPUTERS; COMPUTERS; CURRENTS; 440800* - Miscellaneous Instrumentation- (1990-)