Midwest Research Institute

Brian R Cage

Paul G Gorman

Arbor D Drinkwine

Michael F Fischer

John E Going

Carroll E Ball

David H Steele

Michael J Thornburg

Daniel R Soderberg

A continuous emission monitoring system is disclosed for detecting toxic substances of various types in either stack gas or ambient air. Particular systems are illustrated for monitoring lewisite and chromium(VI). Each system employs a gas sampler that utilizes a high-volume, wet cyclone concentrator unit which scrubs the contaminants from the gas into water or another suitable scrubbing solution. In-line chemical processing of the contaminated sample thus obtained is accomplished either within the sampling unit or by an external chemistry processing module. After processing to provide an analyte in the sample indicative of the presence of a predetermined contaminant, the sample stream is delivered to an ion chromatograph or other analyzer to determine the presence and quantity of the analyte and indicate whether a danger level has been reached. This provides monitoring on an essentially real-time or near real-time basis.

Continuous emission monitoring system

A method is provided for use in generating a chemical vapor stream which may be used to calibrate vapor detectors and for other purposes. The vapor generator is provided with a column having a temperature controlled zone. The chemical is coated onto a carrier such as glass beads and is placed in a temperature controlled zone. A carrier gas is passed over the chemical at a rate which permits the concentration of chemical vapors in the carrier gas to be at saturation. The exiting carrier gas contains chemical vapors at a known concentration. In one embodiment, a second temperature controlled zone is provided downstream, and at a lower temperature than the first zone, to ensure saturation of the carrier gas passing through the second zone.

Method for generating vapor streams

Dissolved components of a liquid sample are recovered for analysis by delivering the sample to a concentrator comprising a cylindrical receptacle into which an uncontaminated gas, such as air, is introduced in a direction tangentially of the cylindrical wall. The gas is under sufficient pressure to effect swirling of the gas and liquid sample and atomization of the sample to rapidly evaporate the same and cause a residue containing the dissolved components to be deposited on the interior surface of the wall. A reconstituting solvent is then admitted to the receptacle to dissolve the residue and provide a reconstituted, concentrated sample for analysis. If desired, the sample may be concentrated to a given volume rather than to complete dryness. In nonlaboratory applications, a dilute liquid substance may be processed by rapid evaporation to provide a final product of desired concentration.

Rapid evaporation method for analysis

An instrument for removing chemical vapors from air and concentrating the chemical vapors in a liquid scrubbing medium has been invented. A cylindrical receptacle receives a preselected amount of scrubbing liquid. Air is pulled tangentially into the cylinder through an inlet slit and swirls toward the cylinder top, carrying the liquid with it so that the cylinder wall is coated with the liquid. At the end of a sampling cycle, the air flow is shut off and the liquid is allowed to settle before being drained off for analysis. A cleaning cycle between sampling cycles is possible, during which the cylinder can be heated by an electrical heater cable.

Growing community of inventors

Shawnee, KS, United States of America

Brian R Cage