836 Series Elemental Analyzer: Determine Oxygen, Hydrogen, and Nitrogen in Inorganic Samples

Features

• A robust sample loading area simplifies routine maintenance and minimizes atmospheric contamination
• Triple IR cells for oxygen detection allows the widest detection range in the industry
• Increase laboratory productivity with automation options
  • Available autocleaner minimizes the need for manual cleaning between analysis
  • 20-position shuttle loader for both crucibles and samples
• Boom-mounted touch-screen interface provides improved ergonomics and intuitive operation
• State-of-the-art infrared (IR) and thermal conductivity (TC) detectors, with no moving parts and no manual adjustments
• Improved TC cell stability
  • Bypassable OMI-2 carrier gas scrubber for enhanced TC cell stability
  • Patented Dyanamic Flow Compensation further enhances TC cell stability

Special Purpose Derivatives

H836EN Model

• High precision analysis of low-level hydrogen in aluminum; ferrous, titanium, and other alloy types are also supported
• Software support for stepped temperature furnace profiles supporting the speciation of surface and bulk hydrogen of aluminum
• EN sample drop, upper electrode, and crucibles are designed to support larger low-level samples like aluminum slugs or depleted uranium pellets
• Replacement for RHEN602 Hydrogen Determinator

O836Si Model

• Unmatched low-level sensitivity with solid-state infrared detection, novel sample loading, and programmable impulse furnace
• Ideal for oxygen detection in the silicon industry (silicon wafers), metals industry, and the electronics industry (high purity copper)

Applications

The 836 series is ideal for the following applications: inorganic materials, ferrous and nonferrous alloys, copper, aluminum, titanium, and refractory materials.

Theory of Operation

The ONH836 Oxygen/Nitrogen/Hydrogen system is designed for simultaneous wide-range measurement of oxygen, nitrogen, and hydrogen content of steel, refractory metals, and other inorganic materials. The instrument features custom software designed specifically for touch operation.

A pre-weighed sample is placed in a graphite crucible which is heated in an impulse furnace to release analyte gases. Oxygen present in the sample reacts with the graphite crucible to form CO and CO₂. An inert gas carrier, typically helium, sweeps the liberated analyte gases out of the furnace, through a Mass Flow Controller, and through a series of detectors. CO and CO₂ are detected using non-dispersive infrared (NDIR) cells. The gas then flows through a heated reagent where the CO is oxidized to form CO₂, and H₂ is oxidized to form H₂O. The gas continues through another set of NDIR cells where H₂O and CO₂ are detected. The CO₂ and H₂O are then scrubbed out of the carrier gas stream, leaving the final analyte, nitrogen, as the only impurity.

A patented Dynamic Flow Compensation (DFC) system is used to add carrier gas as a makeup for the gas lost during the scrubbing process. A Thermal Conductivity (TC) detector is used to detect nitrogen. The detection system is comprised of both NDIR and TC detectors. NDIR cells are based on the principle that analyte gas molecules absorb infrared (IR) energy at unique wavelengths within the IR spectrum. Incident IR energy at these wavelengths is absorbed as the gases pass through the IR absorption cells. The complete set of CO and CO₂ NDIR cells is required to give the most accurate oxygen results for a wide range of sample types and concentrations. TC detection takes advantage of the difference in thermal conductivity between carrier and analyte gases. Resistive TC filaments are placed in a flowing stream of carrier gas and heated by a bridge circuit. As analyte gas is introduced into the carrier stream, the rate at which heat transfers from the filaments will change producing a measurable deflection in the bridge circuit.

The concentration of an unknown sample is determined relative to calibration standards. To reduce interferences from instrument drift, reference measurements of pure carrier gas are made prior to each analysis.