Abstract: A combustion system includes a cylindrical horizontally extending ceramic combustion tube positioned in a furnace. The combustion tube is enclosed at one end and open at the opposite end for receiving a combustion boat carrying a sample to be combusted for subsequent analysis. The tube also receives a support block loosely positioned along the bottom of the tube and contacting the enclosed end for centering the combustion boat and for supporting one end of a sample withdrawal tube with an open end extending in the space surrounding the combustion boat and having an opposite end extending from the combustion tube. A lance tube also extends into the combustion tube for directing the flow of an oxidizing gas such as oxygen into the combustion boat to facilitate oxidation of a sample.

Abstract: A copper sleeve is employed to join a molybdenum disilicide heating rod with a conductor by a brazing process including fluxing the interior of the sleeve, positioning the sleeve partially over one end of the heating rod and heating the junction of the sleeve and rod in a nonoxidizing flame while applying a brazing alloy to the interior of the sleeve. The conductor is then crimped to the opposite end of the sleeve for providing an electrical and mechanical connection of the conductor to the heating rod.

Abstract: An electrode system for resistance furnace includes a pair of electrodes, one of which is movable to selectively clamp a resistive crucible between the electrodes. A specimen placed in the crucible is combusted by the application of electrical power to the electrodes in electrical contact with the crucible. One of the electrodes includes a demountable housing extending therefrom for surrounding a crucible held between the electrodes and sealing the crucible between the electrodes. The demountable housing permits easy cleaning of the system by removal of the housing. In one embodiment one of the electrodes includes a surface configurated to engage the crucible and provide self-centering of the crucible as the electrodes are moved to clamp the crucible therebetween.