INSULATION COVERING OF ELECTRIC DRILLING STRING SEPARATOR Russian patent published in 2006 - IPC E21B47/12 E21B17/00 H01B3/00 

FIELD: mining, particularly electric spacers adapted to transmit drilling direction information.

SUBSTANCE: covering comprises steel substrate, damping layer, insulation layer and glass tissue layer, which are overlapped and connected to the substrate. The damping layer has nickel-aluminum base and is applied by gas-thermal spraying method. Insulation layer is formed of metal oxides, for instance of aluminum oxide, is impregnated with enamel or varnish and is applied by the same method. Glass tissue layer is impregnated with mixture including epoxy resin and metal oxide filler.

EFFECT: increased reliability and service life.

1 dwg