Miniature devices useful for gas chromatography
Patent 4935040 Issued on June 19, 1990. Estimated Expiration Date: 
March 29, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 29, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorAssigneeApplicationNo. 330246 filed on 03/29/1989US Classes:73/23.22, For gas chromatography96/104, Plural separate and distinct stages96/417, WITH SIGNALS, INDICATORS, MEASURING, OR TESTING MEANS210/198.3Thin layer, e.g., plate, etc.ExaminersPrimary: Spitzer, RobertAttorney, Agent or FirmForeign Patent References
International ClassesB01D 015/08G01N 030/66 AbstractLaminated wafers with channels formed therein define a plurality of gas chromatographic columns in a body, with substantially minimal connecting channels between an injector and a detector. One or more of the columns at a time is selected by valve to be receptive of sample gas. Detector and injector cavities have surfaces with the adsorbent phase utilized in the column being further coated on the surfaces, whereby the detector and injector constitute an integral portion of the gas chromatographic column. A channel is formed between wafers each with grooves that have semicircular cross sections so as to form the channel with a circular cross section. A digital gas injector includes a plurality of chambers with respective measured volumes. Valves select one or more of the chambers at a time to be receptive of sample gas from the common inlet. A detector comprises a body having a passage therein receptive of a first flow consisting of a sample gas mixed into a carrier gas, and alternatively receptive of a second flow consisting of a reference gas. Preferably the first and second flows are oppositely directed by valves alternatively through the passage. Boron or silicon nitride film is utilized in cavities in the body so as to provide a structural component for membranes of the valves and for hot wire detectors.Other References
Field of SearchThin layer, e.g., plate, etc. | |
