AN ARRANGEMENT FOR JOINING DOUBLE-WALLED DRILL RODS AND DOUBLE-WALLED DRILL ROD

摘要

The invention concerns an arrangement for the joining of double-walled drill rods that, consisting of two rods (3, 4) one inside the other, limits a central inner channel (5) in which a first fluid can be led, an annular outer channel (6) located between the walls of the inner and outer rods through which a second fluid can led, whereby the arrangement for axial joining of the drill rods at their ends comprises a threaded outer connector (15) that in a fluid-tight manner allows the connection of the opposing outer rods (4) at a joint, and an inner connector (16) that in a similar fluid-tight manner allows connection of the two opposing inner rods 3 at a joint. In order to avoid mixing of fluids, the end of one inner rod is at an inner connector (16) at a joint provided with an arrangement (40) that limits axial passage of driving fluid through the joint, while allowing radial or sideways directed passage of driving fluid through the joint without significant resistance. The invention also concerns a double-walled drill rod.