Abstract: A flow monitoring system includes a first temperature-sensitive resistive device, thermally coupled to a first portion of a fluid transfer apparatus, for producing a first temperature-dependant voltage signal representative of the temperature of the fluid within the first portion of the fluid transfer apparatus. A first current control device, coupled to the first temperature-sensitive resistive device, controls a first current signal flowing through the first temperature-sensitive resistive device. A second temperature-sensitive resistive device, thermally coupled to a second portion of the fluid transfer apparatus, produces a second temperature-dependant voltage signal representative of the temperature of the fluid within the second portion of the fluid transfer apparatus. A second current control device, coupled to the second temperature-sensitive resistive device, controls a second current signal flowing through the second temperature-sensitive resistive device.

Abstract: A sensor system for monitoring cryogenic gas flow through a tube/pipe has at least one sensor coupled to the tube/piping. An alarm circuit is coupled to the sensor for receiving measurement signals from the at least one sensor and for sending an alarm signal when the measurement signal deviates from a predetermined level.

Abstract: A heating element protection apparatus for a mass-flow sensor may include a heating element disposed in a gas, a gas temperature sensor disposed in the gas to sense a temperature of the gas, a slope detector to measure a slope of the temperature as power is supplied to the heating element, and a heating element controller to supply power to the heating element to replace heat dissipated by the gas. The heating element controller may detect a temperature of the heating element and may supply power to the heating element based on the heating element temperature and the gas temperature, and the power may be switched off for a predetermined period of time if a magnitude of the slope is greater than a reference magnitude.

Abstract: A heating resistor type air flow rate measuring apparatus is provided with a couple of heating resistors placed at the positions where those resistors may each interfere thermally with respect to an air flow, and a couple of driving circuits for driving those heating resistors. The air flow rate signal is obtained by calculating the difference between the output signals of a couple of heating resistors in terms of heat radiation rate effected by an air flow, and adding the difference value onto the output signal of one of heating resistors.

Abstract: A flow sensor for detecting flow of fluid includes a thin film portion. The thin film portion has a heater and a detector for detecting temperature around the heater. The heater is made of semiconductor. This flow sensor has high sensor sensitivity with low energy consumption. Further, the sensor has high detection accuracy, and the thin film portion has high endurance. Furthermore, the flow sensor with a passivation film has appropriate thickness so as to improve strength of a thin film portion.

Abstract: A sensor can be configured to generally include a flow channel block having a flow channel formed therein, and a sensor chip for sensing fluid flow, wherein a fluid in the flow channel surrounds the sensor chip. Alternatively, the sensor chip can be fastened at one side to a substrate and on another side of the substrate to a core tube inserted into the flow channel. This core tube provides electrical insulation and corrosion protection to the sensor chip, reduces flow noise, (and by the non-intrusive nature of the measurement) essentially eliminates the risk of fluid leakage, and maintains the fluid super-clean and contamination-free while improving structural integrity for the thermal measurements derived from the sensor chip. The use of such a core tube configuration also can protect the sensor from corrosion, radioactive or bacterial contamination, overheating, or freeze-ups.

Abstract: Gas temperature detection wiring is provided with a first wiring portion disposed parallel to and in close proximity to a flow rate detector portion for a length substantially equivalent to a length of the flow rate detector portion; and a second wiring portion disposed so as to extend from the first wiring portion to an end portion of a pectinate pattern of a gas temperature detector portion. The gas temperature detection wiring is formed so as to connect electrode terminals and the gas temperature detector portion. A high-thermal-resistance portion having increased thermal resistance is constructed by reducing a width of a portion of the second wiring portion.

Abstract: A heating resistor flow rate measuring instrument includes a sub-passage (3) disposed in a main passage (4). A heating resistor (1) and a thermally sensitive resistor (2) are disposed in the sub-passage (3). The sub-passage (3) comprises a first sub-passage having an upstream-side opening face substantially perpendicular to the forward direction of a fluid flow and a downstream-side opening face substantially parallel to the direction opposite to the forward fluid flow, and a second sub-passage having an upstream-side opening face substantially parallel to the forward direction of the fluid flow and a downstream-side opening face substantially perpendicular to the direction opposite to the forward fluid flow. The heating resistor (1) is disposed in the first sub-passage, and the thermally sensitive resistor (2) is disposed in the second sub-passage. The heating resistor (1) is heated to a temperature about 100° C.-300° C. higher than a fluid temperature Ta.

Abstract: Radio-frequency currents vary phases of the radio-frequency voltages appearing at both positive and negative input terminals of an operational amplifier depending on inductance and resistance of conductors forming an electronic device. If the phases of radio-frequency voltages appearing at both positive and negative input terminals of the operational amplifier are different, an offset voltage of the operational amplifier varies to change the operation point of the electronic device resulting in malfunction thereof.

Abstract: An integratable fluid flow and property microsensor assembly is configured to be operably embedded in a microfluidic cartridge of the type used in lab-on-a-chip systems. The assembly is a robust package having a microstructure flow sensor contained within a housing in order to achieve a robust sensing device. The cartridge provides a flow path to the assembly, which directs the fluid across the flow sensor and returns the fluid to the cartridge flow path. The flow sensor monitors the controlled flow of fluid and transmits signals indicative of that flow. The assembly structure provides a robust sensor that is operable and accurate in many different applications.

Abstract: The present invention provides a sensor element having a sensor substrate and a sensing portion supported by the sensor substrate. A resin film is provided between the sensor substrate and the sensing portion. The resin film has a high heat resistance to the temperature of the fabrication process and the use of sensor element, has excellent coverage of a three-dimensional structure, has a flat surface, applies a low stress to the sensing portion, is formed at low temperature, and prevents the sensing portion from being adversely affected in its fabrication process.

Abstract: A flow pickup circuit for receiving a flow signal from a flow sensor and providing a flow indicator signal corresponding to flow characteristics through the flow sensor includes an inner bridge circuit, an outer bridge circuit, and a processor. The inner bridge circuit operates in a constant current mode, and produces a first sensing signal. The inner bridge circuit includes four components connected in a series loop, two of which include the flow sensor. The outer bridge circuit operates in a constant temperature mode, and produces a second sensing signal. The outer bridge circuit includes four components connected in a series loop, one of which includes the inner bridge circuit. The processor receives the first sensing signal and the second sensing signal, and produces the flow indicator signal therefrom. The processor subtracts an ambient temperature component from the second sensing signal to produce a constant temperature flow indicator.

Abstract: Gas temperature detection wiring is provided with a first wiring portion disposed parallel to and in close proximity to a flow rate detector portion for a length substantially equivalent to a length of the flow rate detector portion; and a second wiring portion disposed so as to extend from the first wiring portion to an end portion of a pectinate pattern of a gas temperature detector portion. The gas temperature detection wiring is formed so as to connect electrode terminals and the gas temperature detector portion. A high-thermal-resistance portion having increased thermal resistance is constructed by reducing a width of a portion of the second wiring portion.

Abstract: A mass air flow sensor 10 including a housing 14, an air foil element 16, and at least one sensor element 22 mounted on the surface of the air foil element 16, whereby disruption to the air flow is minimized and performance of the mass air flow sensor 10 in lower air flows is improved.

Abstract: In a gas-flow measuring instrument for measuring a gas flow in an intake gas passage for sucking gas, an abnormal output, deterioration per hour, stain, and breakage of a flow measuring element caused by fluid and foreign materials contained in intake gas are reduced. A gas-flow measuring instrument disposed in an intake gas passage for sucking gas for measuring a gas flow includes a bypass passage for bringing gas flowing along the intake gas passage, a bypass passage inlet opened to the upstream side of a main stream direction of gas in the intake gas passage, and a flow measuring element disposed in the bypass passage.

Abstract: A method and device, employing positive-temperature-coefficient material, for sensing plural properties of a fluid, such as temperature and flow rate. Can be used in a wind gauge or in a device for sensing position of mechanical elements such as valve diaphragms. Single sensor device, with energy and ohmic resistors, produces two voltages which completely characterize temperature and flow rate of fluid under study.

Abstract: A thermal dispersion switch/transmitter for determining flow rate and liquid level in a non-contacting apparatus. A special preparation of one or more small spots in the outside surface of the wall of the conduit, standpipe or container enables one or more thermally sensitive elements to reside very close to the fluid on the opposite side of the wall. A temperature sensor is formed of a raster pattern electrical conductor deposited on a thin, electrically insulative, thermally conductive flat chip. One temperature sensor is time-shared and is periodically self heated and functions as the reference as well as the active or heated sensor of the invention. One alternative is to employ two temperature sensors, one being a reference sensor and the other being the active sensor. An alternative embodiment employs the same construction of one or more small, very thin membrane surfaces to which multiple detectors are mounted inside a probe inserted into the conduit.

Abstract: A thermal mass flow sensor having superior sensitivity and response time includes a flow sensor tube defining an interior channel for fluid flow between input and output ends, a heating element in thermal communication with a portion of the flow sensor tube for heating a fluid flowing through the tube, a pair of spatially compact thermal sensors located at the upstream and downstream ends of the heating element for sensing the temperature of the fluid flowing through the tube at their respective locations and providing a signal representative of the fluid temperature at those locations, and a pair of thermal grounding members on the flow sensor tube, yet positioned at specified locations substantially beyond the heated portion of the tube, for establishing reference temperatures for the fluid flowing therethrough at those locations.

Abstract: An apparatus is provided for determining the mass flow rate of a fluid using thermal means. The apparatus utilizes resistance temperature detectors having substantially linear temperature dependencies to determine the mass flow rate of a fluid. The apparatus maintains a constant ratio between resistances of the first and second resistance temperature detectors, the amount of current necessary to maintain the constant ratio corresponding to the mass flow rate of the fluid. The apparatus includes a microprocessor wherein an algorithm relating the current and mass flow rate including thermophysical properties of the fluid, sensor thermal resistance, and probe stem loss information provides the fluid mass flow rate based upon calibration information. Operation in alternate fluids without the need for recalibration is possible utilizing calibration constants obtained in the primary fluid and substitution of thermophysical properties and stem loss characteristics of each fluid in which operation is desired.

Abstract: The process for the construction of a micro-thermocouple sensor designed to be incorporated in a mass flow meter for the circulation of gaseous fluids, including of the following steps:

Abstract: A heating resistor type air flow rate measuring apparatus is provided with a couple of heating resistors placed at the positions where those resistors may each interfere thermally with respect to an air flow, and a couple of driving circuits for driving those heating resistors. The air flow rate signal is obtained by calculating the difference between the output signals of a couple of heating resistors in terms of heat radiation rate effected by an air flow, and adding the difference value onto the output signal of one of the heating resistors.

Abstract: In flow detection by a thermal-type flow measuring instrument, a flow rate valve with reduced measurement error due to temperature variation can be obtained even under environment where a fluid temperature and a circuit temperature are different. A measurement error due to temperature variation of the fluid of the thermal-type flow measuring instrument can be corrected on the basis of a temperature of the fluid by adjusting the measurement error to be constant ratio irrespective of the flow rate. On the other hand, a temperature characteristic of the circuit is adjusted to be substantially zero %.

Abstract: A first heating resistor is placed in a fluid flow path. A second heating resistor is placed downstream of the first heating resistor. A power supply unit supplies power to each of the first and second heating resistors. A measuring unit measures directly or indirectly a heating factor value of each of the first and second heating resistors. A subtracting unit subtracts the heating factor value of the first heating resistor from the heating factor value of the second heating resistor. A calculating unit performs one of multiplication and division on the subtracting result and the heating factor value of one of the first and second heating resistors.

Abstract: A probe for monitoring groundwater flow seepage velocity and direction has an electrical heater and a plurality of temperature sensors located equidistant from the heater. The probe with the heater and temperature sensors is lowered into a monitoring well and positioned so as to be immersed in the groundwater. Energy is sent to the heater, and the temperature response at the temperature sensors is measured and recorded. From the measured response to temperature, the groundwater flow velocity and direction are computed and recorded. The temperature sensors may be resistance temperature detectors, thermocouples, or any other state-of-the-art temperature sensing device.

Abstract: A thermal dispersion switch/transmitter for determining flow rate and liquid level in a non-contacting apparatus. A special preparation of one or more small spots in the outside surface of the wall of the conduit, standpipe or container enables one or more thermally sensitive elements to reside very close to the fluid on the opposite side of the wall. A temperature sensor is formed of a raster pattern electrical conductor deposited on a thin, electrically insulative, thermally conductive flat chip. One temperature sensor is time-shared and is periodically self heated and functions as the reference as well as the active or heated sensor of the invention. One alternative is to employ two temperature sensors, one being a reference sensor and the other being the active sensor. An alternative embodiment employs the same construction of one or more small, very thin membrane surfaces to which multiple detectors are mounted inside a probe inserted into the conduit.

Abstract: A thermal fluid flow or property sensor having no exposed contact wires or contact pads in the fluid flow path to obstruct measurements, flat fully passivated sensor surfaces and high corrosion resistance is implemented over a honeycombed thermal isolation chamber.