Abstract: A resistance furnace provides an improved upper and lower electrode construction with significantly increased coolant flow. The lower electrode has a tip design that significantly lowers the electrode tip temperature during an analysis. The upper and lower electrodes also cooperate with an improved crucible design to significantly reduce the power required to fuse a specimen contained in the crucible. The furnace uniformly heats the floor and lower side walls of a crucible, which lowers the power requirement for specimen fusion and provides higher structural benefits to provide consistent analysis and manufacturing yields. The crucible has a cylindrical body and pedestal base with an annular smoothly curved concave indentation therebetween.

Abstract: An automatic cleaning assembly for an analytical furnace is detachable from the filter chamber above the combustion tube. The cleaning assembly includes a rotating brush which is lowered through the filter chamber and into the combustion tube while a vacuum is drawn through the lower seal of the combustion tube. This results in a higher vacuum pressure differential and improved flow rate for removing dust from the filter of the furnace and the combustion tube.

Abstract: A graphite crucible has a cylindrical body with an upper opening for receiving a sample for analysis and a disk-shaped pedestal base. The pedestal base includes a bottom surface with a centrally formed circular indentation. An inwardly projecting concave arcuate annular indentation extends between the body and pedestal base with a smoothly curved radius of curvature. The upper and lower walls of the arcuate indentation diverge outwardly at an angle of from about 56° to about 60°.

Abstract: A resistance furnace provides an improved upper and lower electrode construction with significantly increased coolant flow. The lower electrode has a tip design that significantly lowers the electrode tip temperature during an analysis. The upper and lower electrodes also cooperate with an improved crucible design to significantly reduce the power required to fuse a specimen contained in the crucible. The furnace uniformly heats the floor and lower side walls of a crucible, which lowers the power requirement for specimen fusion and provides higher structural benefits to provide consistent analysis and manufacturing yields. The crucible has a cylindrical body and pedestal base with an annular smoothly curved concave indentation therebetween.

Abstract: A graphite crucible has a cylindrical body with an upper opening for receiving a sample for analysis and a disk-shaped pedestal base. The pedestal base includes a bottom surface with a centrally formed circular indentation. An inwardly projecting concave arcuate annular indentation extends between the body and pedestal base with a smoothly curved radius of curvature. The upper and lower walls of the arcuate indentation diverge outwardly at an angle of from about 56 to about 60°. The pedestal base includes a bottom surface with a centrally formed circular indentation.

Abstract: An automatic cleaning assembly for an analytical furnace is detachable from the filter chamber above the combustion tube. The cleaning assembly includes a rotating brush which is lowered through the filter chamber and into the combustion tube while a vacuum is drawn through the lower seal of the combustion tube. This results in a higher vacuum pressure differential and improved flow rate for removing dust from the filter of the furnace and the combustion tube.