초록 ▼

A highly accurate, long life, low cost gas sensor is disclosed, particularly useful for measuring carbon monoxide and other toxic gases in an environment. The gas sensor has a first, sensing electrode and a second, counting electrode. Positioned between the first and second electrodes is an ion cond

A highly accurate, long life, low cost gas sensor is disclosed, particularly useful for measuring carbon monoxide and other toxic gases in an environment. The gas sensor has a first, sensing electrode and a second, counting electrode. Positioned between the first and second electrodes is an ion conducting, solid electrolyte membrane. In response to the presence of a toxic gas introduced to the first electrode, an electric signal is produced between the first electrode and the second electrode. The electric signal changes in response to changes in the concentration of the toxic gas. Detection circuitry measures the electric signal to determine the concentration of the toxic gas. An electrically conductive, hydrophobic top membrane electrically connects the first electrode to the detection circuitry while preventing liquid water from contacting the first electrode. An electrically conductive, hydrophobic bottom membrane electrically connects the second electrode to the detection circuitry. The top and bottom membranes, though hydrophobic, are preferably also microporous so as to be gas permeable, including permeable to water vapor. Preferably the top and bottom membranes are ion insulating as well. Optionally the sensor is provided with a water reservoir to maintain constant relative humidity at the ion conducting electrolyte membrane. The sensor may also have a heating element. Internal and external self-diagnostic features to ensure that the sensor is functioning normally are disclosed, as well as self-calibration features, so as to ensure sensor accuracy.

대표청구항 ▼

[What is claimed is:] [1.]a first electrode and a second electrode;an ion conducting, solid electrolyte membrane positioned between the first electrode and the second electrode, wherein ions migrate through the solid electrolyte membrane in response to the presence of a reactive gas at the first ele

[What is claimed is:] [1.]a first electrode and a second electrode;an ion conducting, solid electrolyte membrane positioned between the first electrode and the second electrode, wherein ions migrate through the solid electrolyte membrane in response to the presence of a reactive gas at the first electrode; anda diagnostic device for diagnosing whether the sensor is operating properly, comprising:A) an applied voltage source coupled to the first electrode and the second electrode;B) a programmed processor, coupled to at least one of the electrodes and to the applied voltage source fori. applying a predetermined applied voltage across the electrodes during at least one charging portion of at least one test periodii. monitoring a monitored voltage across the electrodes in a discharge portion which occurs after the at least one charging portion of the test period and;iii. generating an output error signal if the monitored voltage corresponds to a faulty condition.