TECHNIQUE OF MANUFACTURE OF ELECTRIC DIVIDER OF DRILL PIPE STRING Russian patent published in 2003 - IPC

FIELD: geophysical investigations in holes. SUBSTANCE: invention is related to manufacture of electric divider of drill pipe string used as communication channel to transmit bottom-hole information. Technique includes winding of polymer composite material on threaded connection, screwing of subs along thread through polymer composite material and winding of polymer composite material over outer surface of sub. Winding on threaded connection is carried out in two stages. As result of first stage polymer composite material is formed with simultaneous polymerization, on completion of second stage package is formed over surface of thread by way of preforming. Then package is cooled , subs are screwed, cylindrical package of prepreg is formed over inner surface of subs and binder is polymerized. Layer of phenol- rubber coat can be applied to surfaces of subs prior to winding. Finely dispersed filling agent can be added into polymer binder. Prepreg layers are cut obliquely with regard to direction of base of reinforcing material. Additional separating layers of sealing glass-filled material, for instance, of phenol-rubber adhesive tape, are brought into package of polymer composite material. Prepreg package for inner sheath of divider is assembled from individual layers which width is smaller than circumference length of inner hole of divider. Package of layers of inner sheath is assembled on elastic mandrel and formation is carried out by way of gradual rise of temperature in mandrel with simultaneous growth of temperature. Erosion-resisting coat is deposited on all surfaces of divider. EFFECT: enhanced reliability of connection of sub with insulator, prolonged service life of electric divider. 7 cl, 1 dwg