Leco Corporation

Joel C Mitchell

Ted J Casper

Peter Markel Willis

Gordon C Ford

Mikhail Yavor

Viatcheslav Artaev

Anatoli N Verentchikov

Carlos Guerra

Kim Alvin Marshall

John T Hoss

Steven J Rohaly

James L French

Viatcheslav Arteav

Mark A Hartfield

Brian W Pack

A reagent assembly for a combustion tube includes a reagent tube which is sealably and removably coupled to the open end of the combustion tube such that, when the reagent in the reagent tube is depleted, it can be easily removed without disassembly of the furnace or changing the combustion tube. The reagent tube includes a twist-lock cap to facilitate removal of the reagent tube.

Reagent tube for top loading analyzer

A multiple reflecting time-of-flight mass spectrometer (MR-TOF MS) and method of analysis are disclosed. The flight path of ions is folded along a trajectory by electrostatic mirrors. The longer flight path provides higher resolution while maintaining a moderate instrument size.

Multi-reflecting time-of-flight mass spectrometer and method of use

An analyzer having a combustion furnace includes a gas flow stream including a combustion detector in the stream of byproducts of combustion and a variable volume ballast chamber for receiving byproducts of combustion and which has a movable piston which moves in response to the introduced combustion byproducts. Subsequently, an aliquot sample from the chamber is forced through detectors for elements being detected. The method of analysis incorporating the present invention includes filling a variable volume ballast chamber with byproducts of combustion until combustion completion has been detected and, subsequently, forcing at least an aliquot sample of the combustion byproducts from the variable volume ballast chamber into a flow path including detectors for the elements of interest.

Analyzer with variable volume ballast chamber and method of analysis

An analyzer compensates for gas flow perturbations by providing a makeup flow of carrier gas to maintain the pressure and/or flow rate of analyte and inert gas through a detector constant such that a accurate determination of a low concentration of an analyte in the presence of a high concentration of a second analyte can be accurately determined. In one embodiment, a carrier gas is introduced through a valve responsive to the detected pressure in the gas flow stream between a scrubber and a subsequent detector for maintaining the pressure constant during an analysis. In another embodiment of the invention, a flow transducer is positioned in the gas flow path between the scrubber and detector and coupled to a flow control valve coupled to introduce carrier gas as a function of detected gas flow such that the flow rate of gas into the detector is maintained constant.

Analyzing system for high accuracy nitrogen determination

An analytical crucible is made of a ceramic material with openings to allow the escape of gaseous byproducts of combustion through the crucible while holding the sample. In a preferred embodiment, the crucible is made of a porous ceramic material having a mean pore diameter of from about 150 to 350 microns. The porous ceramic crucible is manufactured of a mixture of at least about 92% alumina and about 7.5% silica. In one embodiment, the crucible is generally cup-shaped.

Analytical crucible

This invention provides a gas atmosphere surrounding a seal between the face of a glow discharge lamp assembly and the sample surface to eliminate the possibility of the introduction of atmospheric gases into the glow discharge lamp. A groove concentric with the O-ring seal in the face of the glow discharge lamp is provided. This groove is supplied with gas slightly in excess of atmospheric pressure. This provides a gas blanket or jacket around the O-ring seal. Any leaks in the O-ring seal would draw the gas rather than atmospheric gases into the lamp. The incorporation of this modification is particularly important when a sample is being analyzed for elements which are also commonly present as atmospheric gases. The invention may be used on DC as well as RF glow discharge lamp assemblies.

Atmospheric seal for glow discharge analytical instrument

A non-conductive isolator for supporting a sample to be analyzed by radio frequency energy induced glow discharge techniques has a conductive ring for coupling a source of radio frequency energy to the same surface of a sample which is in direct contact with the induced glow discharge. An adapter kit for converting a direct current glow discharge analysis apparatus to a radio frequency energy induced flow discharge is also disclosed as well as the method of analyzing non-conductive and sample conductive using a source of RF energy coupled to the same sample surface being analyzed.

Glow discharge analytical instrument for performing excitation and

A multiple frequency plasma torch activation circuit includes a system driver circuit with a pair of different frequency sources and a selector switch which allows one of the sources to be coupled to a splitter assembly which applies signals to a pair of independent power amplifiers having their outputs applied to a combiner assembly and to the plasma torch inductor. A detector circuit provides signals to a power control circuit which includes forward and reflected power monitoring and an impedance matching circuit for optimum coupling of the frequencies to the inductive load.

Growing community of inventors

Bridgman, MI, United States of America

Joel C Mitchell