Back to results
US 6,646,444 B2Granted
Plug-in photoionization sensor
AssigneeMocon, Inc.
InventorsBoris N. Dolgov, Donald K. Forsberg
Life of this patent
Estimating the term…
Abstract
A sensor for detecting volatile organic compounds in ambient air by positioning a detection cell adjacent a gas discharge device to cause molecules of organic compounds to become ionized, and applying an electric field across the collection cell to attract ions and free electrons formed in the cell to develop a current, and amplifying the current magnitude so created.
Claims18
A sensor for detecting small concentrations of volatile organic compounds in ambient air, comprising:
- a. a source of ultra-violet radiation confined in a closed housing having a transparent window;
- b. a detector cell positioned adjacent said window, said detector cell having a disk-shaped dielectric body with a pattern of holes therethrough, said holes being open to said ambient air and said volatile organic compounds;
- each of said holes further comprising an ionization chamber having a depth limited by the thickness of said disk-shaped body;
- metallic layers directly deposited on opposite outside surfaces of said disk-shaped body;
- and a dielectric coating over each of said metallic layers;
- c. means for applying a voltage difference to said metallic layers across said dielectric body, thereby to create an electric field across said body;
- and thereby to create an ion collection field in each of said ionization chambers;
- and
- d. conductors attached to said metallic layers and connected to an amplifier.
6 more elements
A sensor for detecting gases which are ionizable by radiation, comprising:
- a. a closed source of radiation having a window for permitting radiation to pass into the exterior;
- b. a detector cell on the exterior of said source and adjacent to said window, said detector cell further comprising a ceramic disk of a predetermined thickness and having a plurality of openings therethrough to opposite surfaces of said disk, and having a metallic layer deposited on each of said opposite surfaces, and having a dielectric layer overlaying each of said of said metallic layers;
- each of said metallic layer and said dielectric layer respectively having openings in alignment with said plurality of ceramic disk openings;
- said plurality of openings each further comprising an ionization chamber having a depth equal to the thickness of said ceramic disk;
- and
- c. a voltage source connected across said metallic layers for creating and electric field therebetween, and an amplifier connected to receive and amplify current flow created by said electric field.
3 more elements
A sensor for detecting volatile organic compounds in ambient air, comprising:
- a. a gas discharge device containing a gas which is excitable to produce photons in a radio frequency field;
- said discharge device being formed of glass and having an exterior surface at least partially transparent to said photons;
- b. a source of radio frequency and a pair of metallic areas on the exterior surface of said gas discharge device, said source of radio frequency connected to said pair of metallic areas to provide radio frequency excitation to said gas;
- c. a gas detection cell placed adjacent said gas discharge device, said cell being placed to collect ions of volatile organic compounds in ambient air;
- said cell being formed of a ceramic disk material having a predetermined thickness, said material having a plurality of openings therethrough to opposite surfaces of said ceramic disk material, each of said plurality of openings further comprising an ionization chamber having a length equal to said disk predetermined thickness;
- each of said opposite surfaces of said ceramic disk material having a metallic layer coated thereon, and said metallic layers having a dielectric overlayer;
- said respective metallic layers and said dielectric overlayers having a plurality of opening in respective alignment with each of said plurality of ceramic disk openings;
- d. a voltage source connected to said metallic layers to develop an electric field therebetween, and an amplifier connected to said metallic layers to amplify any current developed by said electric field;
- whereby photons from said gas discharge device may ionize molecules of volatile organic compounds in said cell, to form ions and free electrons, and said electric field may attract said ions and free electrons to form a current, and said amplifier may amplify said current.
6 more elements
Dependencies are inferred from the claim text.