Tsi, Inc.

Aerosol Dynamics Inc.

Daniel C Bjorkquist

Susanne Vera Hering

Gregory Stephen Lewis

Frederick R Quant

Robert Caldow

Richard Remiarz

Sreenath Avula

George John Chancellor

Sean Morell

Tyler Anderson

Steven Russel Spielman

Frank D Dorman

Kenneth Farmer

Stanley L Kaufman

Arantzazu Eiguren Fernandez

Miles R Finn

Melissa Grose

David Workman

A system includes a first and second condensation particle counter, each counter having an inlet port, a growth column, and an optical element for counting particles detected at the respective inlet ports. The counters are configured to include a wick in which the wick is wetted by water. A differential pressure sensor is coupled to the first inlet port and coupled to the second inlet port. The sensor is configured to provide a pressure signal. A processor is coupled to memory and configured to receive the first signal, the second signal, and the pressure signal and generate an output corresponding to a ratio of the first signal and the second signal and correlate the ratio with the pressure signal. A housing is configured to receive the first counter, the second counter, the differential pressure sensor, the processor, and the memory.

In situ respirator fit testing

Various embodiments include methods and systems for reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into multiple wicks used for transporting separate portions of an aerosol sample flow, with the wicks extending from a wick stand on a first end to a flow joiner on a second end, combining particles from the separate portions of the aerosol sample flow into a single aerosol stream within the flow joiner prior to transporting the combined aerosol sample stream into a particle detection chamber within the CPC, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water in a collection reservoir, and after receiving a signal corresponding to the excess volume of water, draining the excess volume of water from the collection reservoir. Other methods, systems, and apparatuses are disclosed.

Condensation particle counter false count performance

Various embodiments include methods of reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into one or more wicks, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water into a collection reservoir, and draining the excess volume of water from the collection reservoir. Other methods and apparatuses are disclosed.

Methods and apparatus for enhancing the accuracy of laser optical measuring instruments using fringe pattern spacing are disclosed. The apparatus in one embodiment includes a laser beam source 10, a beam splitter 14, and mirrors 22 to deflect the beams 18, 20 emitted from the beam splitter 14 to a sensing volume. Alternative embodiments include prisms 42, 44, gratings 62 or other optical devices in lieu of mirrors 22. Objects passing through the sensing volume scatter light which is detected by the instrument to determine, among other things, the velocity of the object. The emitted beams 18, 20 are automatically deflected in response to wavelength changes of the laser beam 16 such that variations in the fringe spacing, due to variations in laser beam 16 wavelength, are compensated by variations in the closing angle K of the emitted, deflected beams. The fringe pattern spacing is thereby held more nearly constant enhancing the accuracy of the instrument. Methods of enhancing the accuracy of measurements taken with laser optical measuring instruments are also disclosed.

Laser optical measuring device and method for stabilizing fringe pattern

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Maplewood, MN, United States of America

Daniel C Bjorkquist