Leco Corporation

Charles W Berk

George J Sitek

Peter Markel Willis

Gordon C Ford

Charles B Vallance

Robert N Revesz

Michael P Tabbey

A calorimeter for determining the calorific value of a sample on the basis of the difference in temperature, measured on a real time basis, between the temperature of the water in a bucket containing the sample in a conventional calorimeter bomb and the temperature of the water in a reservoir maintained at substantially ambient temperature. The water from the reservoir is circulated by a pump through a heat exchanger, a water jacket surrounding the bucket and back to the reservoir in an effort to maintain the water in the system at ambient temperature. A method for calculating the corrected bucket temperature rise on the basis of Newton's Law of Cooling and for calculating the gross calorific value of the sample is also disclosed.

Isothermal calorimeter

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.

Electrode system for resistance furnace

An arc control circuit supplies voltage to an electrode of a portable analyzer for striking an arc against a specimen to provide an aerosol of the specimen material for analysis. The circuit includes a source of voltage and voltage dividing means for selectively applying different proportions of the source voltage to the electrode. Sensing means are coupled to the electrode for actuating bypass switching means coupled to the voltage dividing means when the electrode has made contact with the specimen to apply the full voltage of the power supply to the electrode to start the arc. As the electrode tip is withdrawn from the sample a predetermined distance, the desired arc is maintained. Means are provided for quenching the arc by opening the bypass switch to lower the electrode voltage once the arc has been maintained for a desired amount of time.

Arc control circuit

A resistance heating furnace employs a pair of spaced electrodes, one of which is movable to clamp a resistive crucible between the electrodes for passing current therethrough for heating a specimen positioned in the crucible to fuse the specimen. A passageway is provided through one of the electrodes to permit an inert carrier gas to remove gases from the crucible for subsequent analysis. The electrode construction includes a relatively highly conductive base material electrically coupled to a power source for actuating the electrodes and inserts coupled to the surfaces of the electrodes which engage the resistive crucible. The insert material has a relatively high melting point and hardness and a relatively high thermal and electrical conductivity to increase the heating of the crucible and improve the durability of the electrodes. At least one of the electrodes is movable and actuated by a fluid cylinder for clamping the crucible between the electrodes at a constant pressure regardless of the crucible length.

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St. Joseph, MI, United States of America

Charles W Berk