Object:

To provide a gas sensor having a small size and that can suppress gas detection problems caused by frost using only a small amount of power.

Solution: A first electrode terminal (12) includes at least one first connection part (121) connected to a first wire and a first arm part (123) extending from the first connection part (121) to one end (11a) of a resistor (11). A second electrode terminal (13) includes at least one second connection part (131) connected to a second wire and a second arm part (133) extending from the second connection part (131) to the other end (11b) of the resistor (11). The first electrode terminal (12) and the second electrode terminal (13) are fixed to each other and form a water vapor diffusion cavity (S2) extending from the resistor (11) to a wiring member or the vicinity of the wiring member, with at least part of the first arm part (123) and at least part of the second arm part (133) coated with insulation.

The invention relates to a dosimeter material for ammonia and/or amines, the indicator used, as well as processes for their manufacture and use, in particular for quality control of foodstuffs. The dosimeter material for ammonia and/or amines, in particular in the gas phase, comprises an indicator which undergoes an irreversible color change in the presence of ammonia and/or amines, and an immobilization matrix for the indicator that is permeable to ammonia and/or amines, wherein the immobilization matrix is water-impermeable, and wherein the indicator comprises a phosphorus porphyrin activated by covalent bonding to a silanol group and having the formula porphyrin-P(V)X.sub.3, wherein X is Cl or Br.

A measuring device for measuring a concentration of a gas component in a gas includes a flow generating device, a first conduit, a second conduit, and an electrochemical detector configured for sensing the gas component concentration in the gas. The first and second conduits are arranged in parallel, and the flow generating device is connected with an inlet of the first conduit and an inlet of the second conduit. The flow generating device is arranged for generating a gas flow in each of the conduits. The measuring device is arranged to alternately couple either an outlet of the first conduit or an outlet of the second conduit to an inlet of the detector, wherein the first conduit is provided with a reactant for absorbing or stripping the gas component.

Disclosed is a gas sensor for detecting hydrogen gas in a measurement gas atmosphere, including: a first installation part defining a first inner space in communication with the measurement gas atmosphere through a solid electrolyte membrane member; a second installation part defining a second inner space in direct communication with the measurement gas atmosphere; first and second sensor elements respectively installed in the first and second inner spaces; and a calculation unit configured to calculate the concentration of the hydrogen gas according to a potential between the first and second sensor elements. The gas sensor further includes a current detecting portion that detects a current flowing through the first and second sensor elements. The calculation unit is configured to, when the current detected by the current detecting portion is larger than or equal to a threshold value, judge that the hydrogen gas is present at high concentration.

Disclosed is a gas sensor for detecting a measurement target gas in a measurement gas atmosphere, including: a first sensor element; a first installation part defining a first inner space in which the first sensor element is installed; and a casing accommodating therein the first installation part. The casing has an opening formed to introduce the measurement target gas into an inside of the casing. The first installation part has: a first gas introduction hole formed to provide communication between the first inner space and the inside of the casing; and a membrane member arranged to cover the first gas introduction hole and having permeability to water vapor and substantially no permeability to the measurement target gas. At least a portion of the first installation part in contact with the membrane member is made of insulating ceramic material or resin material.

Disclosed is a gas sensor for detecting a measurement target gas in a measurement gas atmosphere, including first and second sensor elements respectively installed in first and second inner spaces of first and second installation parts. The first and second sensor elements have respective heating resistors connected in series and each has a resistance value that varies with change in temperature thereof so that the concentration of the measurement target gas can be calculated according to a potential between the heating resistors of the first and second sensor elements with the application of a constant voltage. The first and second installation parts are located at such positions that allow a maximum temperature difference of 0.4 C. or less between the first and second inner spaces during change in atmosphere temperature from 0 C. to 80 C.

A novel gas and fluid measurement system is provided that can assess undesired gas or fluid leakage in surface casing vents at wellbores or facilities under thermal production enhancement. The system can remove water vapour (steam and/or liquid water) from the gas flow, measure flow rates and volumes of fluids and gases, contain representative fluid and gas samples for collection, and monitor and measure, in real-time, the sulphur gas content, physical water parameters and combustible gas content.

An air monitoring system for analysing an air sample including: a duct arranged such that the air sample flows therethrough from an inlet to an outlet; a relative humidity sensor arranged to measure a relative humidity of the air sample; a heating module including a first heater arranged to heat the air sample; a temperature sensor arranged to measure a temperature of the air sample; a controller arranged selectively to operate the first heater if the measured relative humidity is above an upper threshold; and an analysis module including at least one chemical analysis transducer providing an output corresponding to a presence or concentration of a predetermined substance in the air sample.

A long term portable gas detecting and monitoring apparatus includes a case having a continuous sidewall including a first end closed by a first end cap, and a second end closed by a second end cap connected sealably and removably to the continuous sidewall. The continuous sidewall is triangular between the closed end and the open having three sides and three corners, two of the three sides being straight and equal in length, one of the three sides being rounded, and each of the three corners being rounded. A long term gas detection and monitoring unit mounted in the case includes gas, and temperature and humidity sensors in communication with an ambient atmosphere outside the case, a data processor operatively connected to the sensors, data storage, an information display viewable through the case, and a calibration unit for calibrating the gas sensor to a predetermined gas concentration measured by the gas sensors.

A sensor control apparatus for a gas sensor which detects a particular gas component contained in a gas under measurement. In the case where humidity detection is performed using an electromotive-force-type gas sensor, a sensor control apparatus changes a target voltage of an electromotive force cell to a second target voltage for humidity detection and then to a third target voltage which is lower than a first target voltage which is a target voltage used for detecting the concentration of the particular gas component. In the case where humidity detection is performed using a limiting-current-type gas sensor, the sensor control apparatus changes the voltage applied to a pump cell to a second application voltage for humidity detection and then to a third application voltage which is lower than a first application voltage which is an application voltage used for detecting the concentration of the particular gas component.