Abstract: A scale removal device for scraping off scale deposited on the inner surface of a tube section comprising a rotary shaft to be received within said tube section for advancement and rotation under the action of fluid under pressure pumped into the tube section and having a spiral blade thereabout, a scraper head detachably connected to the leading end of said rotary shaft and having resilient scraper blades thereabout for yieldingly abutting against the inner surface of said tube section and connector means detachably connecting said rotary shaft and scraper head.

Abstract: An eddy current non-destructive metallic flaw inspection apparatus employing a pin coil detector. One end of the pin is made very sharp in order to effectively cause penetration of the concentrated magnetic flux emitted from the sharp point of the pin into the material to be inspected. An outside-type inspector is used to inspect rod products of ferromagnetic material. Two sets of pin coils radially confront to the product from its outside. An inside-type inspector is used to inspect pipe products. The inspector of this type is inserted within the pipe to be inspected and slides longitudinally along the pipe.