Abstract: The graphite sample tube used in flameless atomic spectroscopy is mounted in coaxial bores of two separated heating electrodes, each supported by a cooling jacket for carrying off the excess heat produced by the sample tube. Instead of being sealed with sealing rings, the cooling jackets contain seamless tubing that is tightly pressed in the grooves and carries a flow of suitable coolant. The tubing eliminates fluid eddies and thermal stresses which inevitably leads to coolant leaks. An additional feature is that one of the two cooling jacket housings is pivotally movable by a pneumatic actuator for easy removal of the graphite sample tubes and the inspection of the bores of the electrodes.