The sensor consists of an induction loop. Electric current generates a magnetic field, which collapses generating a current that falls asymptotically toward zero from its initial level when the input electricity ceases. The inductance of the loop changes according to the material inside it and since metals are much more effective inductors than other materials the presence of metal increases the current flowing through the loop. This change can be detected by sensing circuitry, which can signal to some other device whenever metal is detected.
Common applications of inductive sensors include metal detectors, traffic lights, car washes, and a host of automated industrial processes. Because the sensor does not require physical contact it is particularly useful for applications where access presents challenges or where dirt is prevalent. The sensing range is rarely greater than 6cm, however, and it has no directionality.
WIPO PUBLISHES PATENT OF SIEMENS FOR "INDUCTIVE SENSOR DEVICE AND INDUCTIVE PROXIMITY SENSOR WITH AN INDUCTIVE SENSOR DEVICE" (GERMAN INVENTOR)
Jan 16, 2012; GENEVA, Jan. 16 -- Publication No. WO/2012/004251 was published on Jan. 12. Title of the invention: "INDUCTIVE SENSOR DEVICE AND...
US Patent Issued to Pepperl + Fuchs on April 12 for "Method for the Detection of a Predamping State and Inductive Sensor with Predamping Detection" (German Inventor)
Apr 18, 2011; ALEXANDRIA, Va., April 18 -- United States Patent no. 7,924,105, issued on April 12, was assigned to Pepperl + Fuchs GmbH...