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US 4,935,040 AGranted
Miniature devices useful for gas chromatography
AssigneeThe Perkin-Elmer Corporation
InventorMichel G. Goedert
Life of this patent
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AssigneeThe Perkin-Elmer Corporation
InventorMichel G. Goedert
Estimating the term…
Laminated 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.
A unitary gas chromatographic device comprising a body formed of a multiplicity of wafer members laminated together, the wafer members having mating surfaces with channels formed therein such as to define a plurality of gas chromatographic columns in the body, and further comprising injector means disposed in the body for injecting sample gas into the columns, and one or more gas valves disposed in the body for selecting one or more of the columns at a time to be receptive of the sample gas from the injector means.
A gas chromatographic device comprising a body having therein a gas chromatographic column with a gas inlet and a gas outlet, the column having inside column walls with an adsorbent phase being coated thereon, the body further having a detector cavity therein juxtaposed with the gas outlet to be receptive of sample gas from the column, the detector cavity having at least one component associated therewith in the detector cavity to provide detector means for detecting a characteristic of the sample gas, and the detector cavity and the at least one associated component having collective surfaces thereof in the detector cavity with an adsorbent phase being further coated on the collective surfaces, whereby the detector means constitutes an integral portion of the gas chromatographic column.
A gas chromatographic device comprising a body having therein a gas chromatographic column with a gas inlet and a gas outlet, the column having inside column walls with an adsorbent phase being coated thereon, the body further having a detector cavity therein juxtaposed with the gas outlet to be receptive of sample gas from the column, the detector cavity having at least one component associated therewith in the detector cavity to provide detector means for detecting a characteristic of the sample gas, and the detector cavity and the at least one associated component having collective surfaces thereof in the detector cavity with an adsorbent phase being further coated on the collective surfaces whereby the detector means constitutes an integral portion of the gas chromatographic column, the device further comprising injector means juxtaposed with the gas inlet for injecting sample gas into the column, the injector means being formed of at least one injector cavity in the body, the at least one cavity having injector surfaces thereof with an adsorbent phase being further coated on at least a portion of the injector surfaces whereby the injector means constitutes a further integral portion of the gas chromatographic column.
A gas chromatographic device comprising a body having therein a gas chromatographic column with a gas inlet and a gas outlet, the column having inside column walls with an adsorbent phase being coated thereon, the device further comprising injector means juxtaposed with the gas inlet for injecting sample gas into the column, the injector means being formed of at least one injector cavity in the body, the at least one cavity having injector surfaces thereof with an adsorbent phase being further coated on at least a portion of the injector surfaces whereby the injector means constitutes an integral portion of the gas chromatographic column.
A unitary gas chromatographic device comprising a body formed of a multiplicity of wafer members laminated together, the wafer members having mating surfaces with channeling formed therein such as to define in the body a gas chromatographic column having a column inlet and a column outlet and further define in the body an impedance channel having an impedance inlet and an impedance outlet, the impedance channel having a resistance to gas flow similar to that of the column, the body further having therein a carrier gas duct receptive of a source of carrier gas, the carrier duct having a first branch connected to provide a carrier gas flow into the column inlet and a second branch connected to provide a reference gas flow into the impedance inlet, the device further comprising injector means disposed in the body for injecting sample gas into the first carrier gas flow proximate the column inlet, the body further having a detector passage therein having a first terminal connected to the column outlet and a second terminal connected to the impedance outlet, the device further comprising a first valve in the body connected between the first terminal and a vent, a second valve in the body connected between the second terminal and a vent, valve control means for alternatively opening the first and second valves to oscillate between selecting the first flow or the second flow through the passage while simultaneously venting directly the second or first flow correspondingly, while bypassing the passage, detector means disposed in the passage for producing a time varying signal representing a characteristic of the gas in the passage, and processing means receptive of the signal for comparing signals for the first and second flows to present a differential characteristic representing the sample gas.
A gas injector useful for gas chromatography, comprising a body having therein a plurality of chambers with respective measured volumes, the body further having therein a common gas inlet receptive of sample gas and further having a common gas outlet, the injector further comprising valve means disposed in the body, the valve means being responsive to controller means for selecting one or more of the chambers at a time to be receptive of sample gas from the common inlet, and the injector further comprising pressure means for forcing the sample gas from the one or more selected cavities through the outlet, whereby the total of the respective measured volumes of the selected one or more chambers corresponds to a predetermined volume of sample gas forced through the outlet, and different predetermined volumes are provided by control of the valve means.
A detector for measuring a characteristic of a sample gas, comprising a body having a passage therein receptive of a first flow consisting of a sample gas mixed into a carrier gas, the passage alternatively being receptive of a second flow consisting of a reference gas, the detector further comprising valve means for selecting between the first and second flows in the passage, valve control means for controlling the valve means to oscillate between selecting the first flow or the second flow through the passage, detector means for producing a time varying signal representing a characteristic of the gas in the passage, and processing means receptive of the signal for comparing signals for the first and second flows to present a characteristic representing the sample gas.
Dependencies are inferred from the claim text.