687 results about "Hydrogen sensor" patented technology

This invention provides ways to fabricate nanotubes and nanobead arrays by utilizing nanopores in anodic aluminum oxide (AAO) membranes. Nanotubes of bismuth and other low melting point metals with controlled diameters and lengths can be fabricated by sintering AAO coated with appropriate metals at temperatures above their melting points. Carbon nanotubes may also be readily formed by carbonizing a polymer on the interior walls of the nanopores in AAO membranes. Palladium nanobead arrays which can be used as ultrafast hydrogen sensors are fabricated by coating the flat surface of AAO membranes with controlled pore-wall ratios.

The invention relates to a hydrogen sensor and a Pd film hydrogen sensitive system, wherein the hydrogen sensor comprises introduction fiber, reflection fiber and a hollow tube, a surface of which has a Pd or Pb alloy film, the introduction fiber and the reflection fiber are respectively connected with two ends of a cavity of the hollow tube, two opposite fiber end faces are parallel and constitute an intervene cavity with the tube cavity. According to the Pd film hydrogen sensitive system, light with wide spectrum is transmitted to the introduction fiber of a hydrogen sensor, and intervene light generated on two opposite end of the introduction fiber and the reflection fiber is received, change of the length of the intervene cavity is determined through collecting intervene spectrum signals, further computing concentration of hydrogen. The invention overcomes problems that it is difficult to realize high resolution stable measurement due to light source fluctuation and optical fiber disturbance and the like, and is easy to be affected by temperature in prior art. Measurement result is correct and temperature is strong, cost is low.

A controller in a fuel cell system performs various operating parameter checks at a predefined schedule, including one or more of a stack current check; a stack voltage check; a cell voltage check; a purge cell check; an oxygen concentration check; a hydrogen concentration check; a stack temperature check; an ambient air temperature check; a fuel pressure check; and an airflow rate check; a hydrogen sensor heater check; a battery voltage check; a microcontroller self-check; and / or toggling a watchdog. The frequency of the checks are set relative to achieve an efficient control of the fuel cell system by selectively distributing the load on the microcontroller.

HEMT-based hydrogen sensors are provided. In accordance with one embodiment, a normalized sensor is provided having a control HEMT-based sensor connected in series to an active HEMT-based sensor. The control and the active sensor include functionalized gate regions. The gate functionalization for both the control and the active sensor is the same material that selectively absorbs hydrogen gas. The control sensor further includes a protective layer to inhibit its gate functionalization from being exposed to hydrogen. In one embodiment, the final metal for the contacts of the sensors is used as the protective layer. In other embodiments, the protective layer is a dielectric or polymer.

The invention discloses a full-automatic high-pressure container gas circular charging and discharging fatigue test system which not only can realize the full-automatic control of the high-pressure gas circular charging and discharging fatigue test but also can carry out the on-line automatic detection to the fatigue condition of the high-pressure container. The automatic control of the circular charging and discharging is realized through the dynamic response signals of a temperature sensor arranged inside the tested container, the dynamic response signals of each pressure sensor on the high-pressure pipelines and switching of solenoid valves controlled by the control strategy. The gas medium in the circular charging and discharging process can be recycled after the pressurizing by a pressure-releasing receiving tank and a gas compressor so as to avoid the gas waste and environment contamination. The dynamic fatigue states of the high-pressure container in the circular charging and discharging process are acquired through the changing of response signals of a hydrogen sensor arranged in a sealed bin of the tested container and the response signals of a strain sensor stuck to the surface of the tested container; and when the released hydrogen concentration reaches the set value or the strain of the container material exceeds the set value in the charging and discharging process, the fatigue test system is closed automatically.

The present invention provides a delay line SAW device fabricated on a lithium niobate substrate and coated with a bilayer of nanocrystalline or other nanomaterials such as nanoparticles or nanowires of palladiumn and metal free pthalocyanine which will respond to hydrogen gas in near real time, at low (room) temperature, without being affected by CO, O2, CH4 and other gases, in air ambient or controlled ambient, providing sensitivity to low ppm levels.

The invention discloses an integrated hydrogen sensor made from mixed graphene film, noble metal particles and metallic oxide materials and a preparation method of the integrated hydrogen sensor. The sensor comprises a substrate, a heating electrode, a heat-conducting insulation layer and a detection electrode; the heating electrode is placed on the substrate; the heat-conducting insulation layer is placed between the heating electrode and the detection electrode and further the sensor further comprises a metallic oxide film deposited on the detection electrode, the noble metal particles deposited on the metallic oxide film, and the graphene film covers the metallic oxide film on which the noble metal particles are deposited. The noble metal particles covering the metallic oxide film are single atoms, wherein the covering rate is 0.05-100 percent, the particle size is 0.2-0.4 nanometers, and the noble metal particles are randomly and uniformly arranged. The metallic oxide film is 10 nanometers to 2 micrometers in thickness. The graphene film is 0.5-1.2 nanometers in thickness. By adopting the integrated hydrogen sensor provided by the invention, high-sensitivity and high-selectivity detection and monitoring for hydrogen can be simultaneously achieved.

A degradation diagnosis method for simply performing degradation diagnosis of a gas sensor such as a hydrogen sensor. The hydrogen sensor has a reference detector member and common detector member, with each detector member respectively constituted of a detector element and temperature compensating element that form a pair. Power is normally supplied to the common detector member, which performs concentration detection of the hydrogen gas. When performing degradation diagnosis of this common detector member, concentration detection is performed simultaneously by each detector member for the gas of the prescribed hydrogen concentration by supplying power to both the common detector member and reference detector member and comparing the output value of the common detector member and the output value of the reference detector member.

The invention discloses a multi-layer composite sensitive film optical fiber hydrogen sensing probe and a manufacturing method thereof. The probe is formed by the butt welding of a D-shaped fiber grating (6) coated with a hydrogen sensitive film (10) and a reference grating (5) which has the same central wavelength and is not coated with film, wherein the D-shaped fiber grating (6) coated with the hydrogen sensitive film (10) is prepared by performing magnetron sputtering coating of a SiO2 film (13), a SiO2-Pd mixed film (14) and a Pd film (15) on a fiber grating which is subjected to side polishing treatment; and the SiO2 film has the thickness of 1-100nm, the SiO2-Pd mixed film has the thickness of 1-100nm, and the Pd film has the thickness of 10nm to 20 mu m. The manufacturing method comprises a step of combining the hydrogen sensitive film with the anti-electromagnetic interference D-shaped fiber grating to form an optical fiber hydrogen sensing probe. Due to the adoption of magnetron sputtering, heat treatment and a temperature compensation technology, the accuracy and sensitivity of the sensor are greatly improved; moreover, the volume of the sensing probe is greatly reduced, and the probe contributes to implementing the miniaturization of an optical fiber hydrogen sensor.

A hydrogen sensor 25 has a fitting base plate 29 in which a gas-sensing chamber 34 is formed, a specimen gas intake 35 formed on said fitting base plate 29, opening toward an exit passage 24 and introducing hydrogen gas into the gas-sensing chamber 34, a gas-sensing element 39 held in the gas-sensing chamber 34 and adapted to sense hydrogen gas, and a water-repelling filter 44 covering the specimen gas intake 35.

A hydrogen gas sensor and / or switch fabricated from arrays nanowires composed of metal or metal alloys that have stable metal hydride phases. The sensor and / or switch response times make it quite suitable for measuring the concentration of hydrogen in a flowing gas stream. The sensor and / or switch preferably operates by measuring the resistance of several metal nanowires arrayed in parallel in the presence of hydrogen gas. The nanowires preferably comprise gaps or break junctions that can function as a switch that closes in the presence of hydrogen gas. Consequently, the conductivity of the nanowires of the sensor and / or switch increases in the presence of hydrogen

The invention discloses a tail gas buffer dilution treatment method for safe emission of hydrogen from a fuel cell vehicle and a device thereof. The device comprises a hydrogen buffer, a flow control valve, a draining valve, a flame arrester, an earth terminal, an emergency hydrogen exhaust valve, a hydrogen sensor and a control module. The pulse hydrogen emitted from an anode side of the fuel cell is firstly buffered by the buffer, and a small stream of air introduced from an air path emitted from the cathode side dilutes and sweeps the hydrogen in the buffer; then the diluted hydrogen emitted from the buffer and the gas from a main air pipeline are mixed, thus the volume concentration of the tail hydrogen emitted from the fuel cell vehicle is controlled below the explosion limit concentration 4%, and the purified water discharged from a condenser can be recycled. The tail gas buffer dilution treatment device utilizes the techniques of self-diffusion, multi-tube pass buffer, air mixing and exchange, expansion, condensation and the like to buffer and dilute the hydrogen-containing tail gas emitted from the fuel cell vehicle and separate the water and gas in the hydrogen-containing tail gas, thus eliminating the possible fire hazard and ensuring the safe running of the fuel cell vehicle.

In a hydrogen gas line where the composition of the gas is primarily hydrogen, impurities present in the gas line will typically reduce the speed of sound. Accordingly, an acoustic sensor can be used in such a hydrogen gas line to indicate when impurities have accumulated in the gas line. In particular, the hydrogen gas line may be in a fuel line for an electrochemical fuel cell system. The sensor may comprise transducers, more particularly piezoelectric transducers, as both sound detectors and / or sound generators. Further, the sensor can measure either the speed or frequency of sound to determine the hydrogen concentration. If the fuel is recirculated back to the anode inlet, such a hydrogen sensor in the anode exhaust may be used to determine when it is beneficial to purge the anode exhaust to the external atmosphere.

A hydrogen sensor 25 has a fitting base plate 29 in which a gas-sensing chamber 34 is formed, a specimen gas intake 35 formed on said fitting base plate 29, opening toward an exit passage 24 and introducing hydrogen gas into the gas-sensing chamber 34, a gas-sensing element 39 held in the gas-sensing chamber 34 and adapted to sense hydrogen gas, and a water-repelling filter 44 covering the specimen gas intake 35.

The present invention provides for variable-range hydrogen sensors and methods for making same. Such variable-range hydrogen sensors comprise a series of fabricated Pd—Ag (palladium-silver) nanowires—each wire of the series having a different Ag to Pd ratio—with nanobreakjunctions in them and wherein the nanowires have predefined dimensions and orientation. When the nanowires are exposed to H2, their lattace swells when the H2 concentration reaches a threshold value (unique to that particular ratio of Pd to Ag). This causes the nanobreakjunctions to close leading to a 6-8 orders of magnitude decrease in the resistance along the length of the wire and providing a sensing mechanism for a range of hydrogen concentrations.

The present invention provides for a method and apparatus for hydrogen detection and dilution. The present invention uses an enclosure within which a variety of components of a fuel cell system are located and a ventilation stream to vent the enclosure which is induced by operation of a compressor that also is operable to supply the oxygen to the fuel cell system. The ventilation stream is directed through an outlet in the enclosure that contains a hydrogen sensor that is operable to both detect the presence of hydrogen and to consume hydrogen within the ventilation stream prior to being exhausted from the enclosure. The ventilation stream, alternatively, can be induced by operation of a fan driven by a motor which operates independently of the operation of the oxidant delivery system.

Single-walled carbon nanotubes (SWNTs) are decorated with metal nanoparticles to form high-performance flexible hydrogen sensors. The special process to form the high-performance flexible hydrogen sensors can combine a dry transfer printing technique and modification of SWNTs with palladium (Pd) nanoparticles to provide high-performance hydrogen sensors with excellent mechanical flexibility on plastic substrates. Two approaches can be used to decorate the SWNTs. One is physical deposition, such as electron beam evaporation (EBE) and the other is electrochemical deposition which can selectively grow palladium nanoparticles on the surface of the SWNTs, resulting in significantly decreasing the use of palladium. Preferably, the Pd nanoparticles are deposed on the SWNTs in a discontinuous arrangement so that the Pd nanoparticles are spaced away from each other to form individual discontinuous Pd nanoparticles rather a continuous Pd film. Advantageously, the SWNTs are arranged with substantial semiconducting pathways. Desirably, the high-performance flexible hydrogen sensors have an excellent response and recovery time, provide superior sensitivity for detecting hydrogen, and are bendable to conform to the contours of other structures.

A gas monitoring system and a gas monitoring method make it possible to identify plural gas sensors having a single specification and which are connected to one trunk line. Trunk line connectors have identification configurations for allowing information concerning positions where the trunk line connectors to be identified are arranged. Hydrogen sensors have a single specification (the same specification). When connectors of the hydrogen sensors are fitted to the trunk line connectors, the hydrogen sensors store the sensor IDs, which are assigned to the hydrogen sensors, in memory units based on the identification configurations of the trunk line connectors.

A hydrogen sulfide sensor is made from a metal acetate film, such as a thin film of copper acetate, formed on a set of monitoring electrodes, by evaporation of a metal acetate aqueous solution disposed on the electrodes, for detecting a weak gas, such as hydrogen sulfide, carried in a gas carrier, such as a nitrogen carrier, for detecting low concentration of the weak gas, such as ten ppm, when the conductivity of the film changes by several orders of magnitude, that produces a metal sulfide, such as copper sulfide, that is a good electrical conductor at room temperature, for example, as the metal acetate is converted directly to a metal sulfide upon exposure to hydrogen sulfide.

The invention is directed at a method of sensing hydrogen gas in a liquid comprising: providing a measuring device comprising a hydrogen sensing chamber and a palladium hydrogen sensor mounted in contact with said chamber, positioning a hydrogen permeable membrane between the liquid and the hydrogen sensor and creating a headspace, selectively providing air to the sensor headspace, thereby bringing air into contact with said palladium sensor to refresh the palladium, after the palladium sensor is refreshed shutting off air flow to the sensor headspace, bringing liquid into said chamber, allowing hydrogen to pass through the membrane and reach equilibrium, and reading the hydrogen concentration.

A preparation method of a titanium dioxide nanotube based hydrogen sensor comprises steps of: pretreatment on high purity titanium sheets; a first anodic oxidization on titanium sheets; a second anodic oxidization on the titanium sheets; an annealing treatment on titanium sheets with TiO2 nanotubes grown on, after the second anodic oxidization; deposition of precious metals Pt and Pd on the TiO2 nanotubes treated with the high temperature annealing to obtain the hydrogen sensor. A preparation technology of the method is simple, conveniently operated and reasonably designed; the TiO2 nanotube array hydrogen sensor has good sensitivity and selectivity, but requires a high operating temperature, so as to restrict application fields of the sensor. Noble metal coatings of platinum and palladium are compounded on the TiO2 nanotubes; the noble metal coatings have strong absorptivity to H2 and dissociation on H2 absorbed thereon, so as to accelerate interaction between dissociated H and the TiO2 nanotube surfaces, further enhance TiO2 sensitivity to H2, and effectively promote practicability process of the TiO2 nanotube array based hydrogen sensor.

A hydrogen detecting system is characterized by a passive surface acoustic wave (SAW) sensor. The sensor includes a piezoelectric substrate having a self assembled monolayer arranged on at least a portion of the substrate to create a hydrophobic surface. A palladium nanocluster thin film is deposited on the monolayer and an interdigital SAW transducer is disposed upon the piezoelectric substrate for conversion of an RF signal into an acoustic wave and vice versa. At least one additional SAW element is also disposed on the substrate and spaced from the SAW transducer. The SAW element receives a signal from the SAW transducer and produces a response signal. The response signal is modified by the palladium nanocluster film due to a change in conductivity of the palladium nanocluster film upon exposure to hydrogen. This change in the response signal is measured by an interrogator, and yields a measure of the hydrogen concentration to which the sensor was exposed.

The invention relates to a micro hydrogen sensor, in particular to preparation and performance detection of a palladium-nanometer-scale stannic oxide film type electrode in a hydrogen sensor. In the micro hydrogen sensor, aluminum oxide is used as a substrate, and palladium and nanometer-scale stannic oxide deposit on the substrate as a hydrogen sensitive material by adopting a method of electrode-free electrolysis. The invention provides a preparation method of the palladium-nanometer-scale stannic oxide film type electrode, the palladium-nanometer-scale stannic oxide film type electrode better enhance the performance of the hydrogen sensor as the hydrogen sensitive material, development and application of a nanometer-scale stannic oxide material are beneficial to enhancing the performance of the stannic oxide hydrogen sensor, and stannic oxide is doped into noble metals such as the palladium and the like to enhance the flexibility, reduce the response time and also lower the operation temperature. The invention has the advantages of shorter response time, better stability, better repeatability, micro sensor size, low processing cost and being beneficial to minaturization, integration and industrialization, is particularly suitable for room temperature detection and can also recycle ceramic wafers of a substrate carrier.

The present invention provides for novel hydrogen sensors and methods for making same. In some embodiments, such novel hydrogen sensors are continuous-range hydrogen sensors comprising Pd—Ag nanoparticles arrayed as nanowires or two-dimensional shapes on a resistive surface. Such continuous-range hydrogen sensors are capable of measuring a wide range of hydrogen gas concentration over a wide temperature range. Unlike existing hydrogen sensors that experience a large change in resistance at a certain hydrogen concentration, the continuous-range hydrogen sensor of the present invention changes resistance continuously over a broad range of hydrogen concentration. This continuous change varies slowly with hydrogen concentration and is predictable such that the continuous-range hydrogen sensor can be used to measure hydrogen concentration continuously from a few ppm to 40,000 ppm level or higher over a broad range of temperatures (e.g., −40° C. to +150° C.).

The invention relates to a hydrogen sensor, in particular to a piezoelectric hydrogen sensor and preparation and application of the same. The piezoelectric hydrogen sensor comprises a quartz crystal microbalance and hydrogen sensitive materials, wherein, the hydrogen sensitive materials are nanophase materials which are loaded with Pd nano microparticles and are then fixed on a wafer of the quartz crystal microbalance. The hydrogen sensor can quantitatively detect the concentration of hydrogen at room temperature, and have simple and convenient operation and good repeatability. The piezoelectric hydrogen sensor prepared adopts a carbon nano tube to load Pd, overcomes the defect of loose bonding force of the Pd and matrixes, improves the sensitivity of hydrogen detection and also has the advantages of simple technique, wide application range, low manufacturing cost and so on.

An apparatus comprising a processing unit; a feed conduit and an effluent conduit connected to the processing unit; at least one operating parameter device associated with the processing unit, the feed conduit, the effluent conduit or a combination thereof; a catalytic alloy hydrogen sensor in fluid communication with the processing unit, the feed conduit, the effluent conduit or a combination thereof; and a computer processor electrically connected to the catalytic alloy hydrogen sensor, has been developed. The apparatus may also have at least one operating parameter device and an electrical connection between the computer processor and at least one of the operating parameter devices. The apparatus may be used for the control of a processing unit or operation. A pressure indicator may be positioned to indicate the pressure of fluid passing through the catalytic alloy hydrogen sensor and there may be an electrical connection between the computer processor and the pressure indicator. The catalytic alloy hydrogen sensor may be a palladium-nickel catalytic alloy hydrogen sensor.

The invention belongs to the technical field of electric-power equipment detection, and in particular, relates to a detection device of dissolved gases in transformer oil based on infrared spectrum absorption. The device includes a light source system unit, a sensing arrangement unit and a detection acquisition and analysis unit; the light source system unit is composed of a high-power supercontinuum broadband light source, a light source controller and a photoswitch and is used for realizing output multiplexing control of the light source; the sensing arrangement unit is formed by arranging one sensing path of fiber Bragg grating hydrogen sensor series-connection wavelength division multiplexing and the other one sensing path of hollow photonic crystal optical fiber internal spectrum absorption sensing in a cavity body of an oil-immersed power transformer; the detection acquisition and analysis unit is composed of a wavelength demodulation device, a light intensity detector and a data acquisition and analysis device, the wavelength offset and the spectral absorption intensity of fiber Bragg grating hydrogen sensors are detected, and the data acquisition and analysis device records data and types and contents of corresponding fault gases are obtained by calculation; and on the basis, insulation conditions of the transformer oil are evaluated, positioned, analyzed and forecasted.