PURPOSE: To facilitate the exchange of electrodes and to prolong the exchange cycle by fitting a porous plastic pipe onto the plural aperture of the lower part of a protective pipe and providing a cylindrical casing on the outer side thereof, packing a carbon material into respective spaces, and holding the electrodes in the protective pipe.
CONSTITUTION: The porous plastic pipe 8 having open cells is fitted onto the synthetic resin protective pipe 3 having the plural apertures 5 in the lower part so as to shield the apertures 5 and the cylindrical casings 9, 9', 9'' are mounted coaxially onto this pipe 8. The plural electrodes 6 are held in the desired position in the protective pipe 3 and the carbon material is packed in the space in the protective pipe 3 and the spaces between the pipe 8 and the casings 9, 9', 9'', respectively. The electrodes 6 of the electrode device constituted in such a manner are connected to an embedded pipe 12 via a DC power source 11 by lead wires 10. The electrode device for corrosion prevention of the metallic material embedded underground which has a good installation characteristic and exerts a corrosion preventive effect even to a remote place is obtd. in this way.
KINOSHITA AKIRA
KOSHIMIZU YUICHIRO
HAYAKAWA TAKEO
SAYAMA DAIHACHI
ISHIKAWA MITSUO
NIHON BOSHOKU KOGYO