Improvements in and relating to apparatus for detecting the presence of metallic particles in non-metallic substances

摘要

465,338. Magnetic tests; locating conductors. BRITISH THOMSONHOUSTON CO., Ltd., and MAYO, C. G. Nov. 5, 1935, No. 36282/34. [Class 37] Metallic particles in a non-metallic substance are detected by passing the substance through a magnetic field produced by a primary winding 2, detection being observed by providing two opposed closely balanced secondary coils 3 with their axes normal to the field direction so that normally the field produces no resultant induced voltage, but on the presence of a magnetic or non-magnetic particle 1 in the substance the field is distorted and a resultant induced voltage is applied to the amplifier 4. The output current of the amplifier may operate a relay to stop the flow of the substance under test.