Method and apparatus for detecting the presence of metallic reinforcing elements in the interior of a concrete - component

摘要

The method is applied to detect the existence of a metal reinforcing element inside a concrete component within a predetermined distance from a bore made in the concrete. A magnetic or e.m. field of predetermined configuration and strength is produced by a probe introduced into the bore. A metal component, if near enough, will influence the field. This effect is used to generate an acoustic and/or optical signal. The probe (20) used consists of a shaft (22) insertable in a trail bore (16) in a concrete section (10). A generator at the front end of the shaft is used to generate the field. A sensor arrangement measures the field strength and/or flux of the field produced as well as detecting a change causes by the presence of a metal reinforcing element (14) near the bore. The field generator can consist of two permanent magnets (M) set at a distance from each other with like poles facing each other. The sensor arrangement can be provided by at least two field plates or Hall elements measuring the magnetic flux, an amplifying circuit receiving the electric signals produced.