Abstract: There is disclosed a handheld air flow velocity measurement probe that includes a bridge circuit assembly having an airflow velocity sensor that is a resistance temperature detector (RTD) and a digitally controlled resistive element to dynamically adjust and maintain the resistance of the velocity sensor within the overheat temperature predefined range. The velocity measurement also uses a separate temperature sensor to sense the temperature of the air or gas flow. A humidity sensor is also included remote from the other sensors to measure humidity in the gas flow to be measured. All of the above described components are housed at a probe tip instead of a base as in most standard handheld probes and the digital interface at the probe tip allows the user to replace a bulky, expensive telescoping antenna with stackable extender scheme.

Abstract: A flow velocity sensor includes a substrate, a resistor, and a signal processing section. The substrate has first and second substrate surfaces outwardly opposite to each other. The first substrate surface is exposed to a fluid. The resistor is mounted on the second substrate surface. The resistor has a heat generating portion facing the second substrate surface. The signal processing section is configured to receive a signal from the resister. The signal from the resistor represents heat dissipation of the resistor. A fluid velocity is detected based on the signal from the resistor.

Abstract: A gases flow rate sensing system may be configured to operate in at least two different target temperature modes, based upon a measured temperature of the gases flow. In some embodiments, the gases flow sensing system may have a voltage divider containing a thermistor. The gases flow rate may be determined based upon a voltage output indicating an amount of power needed to maintain the thermistor at a target temperature as specified by the target temperature mode, and a measured temperature of the gases flow.

Abstract: A portable therapeutic fluid delivery device with a flow detector comprising a heating element and two temperature sensors is presented. Upon activation of the heating element, a flow condition of the fluid inside the delivery tube is determined based on a signal provided by the temperature sensors. A temperature gradient within the therapeutic fluid is detected. The determined flow condition can be one of: air bubbles within the delivery tube, occlusion within the delivery tube, or leakage within the delivery tube. The device can have two parts, for example, a reusable part and a disposable part. Upon pairing of these parts, the heating element and the temperature sensors touch the delivery tube.

Abstract: An apparatus includes a microfluidic channel and a flow sensor along the microfluidic channel. The flow sensor includes a heat emitting resistor for connection to an electric current source, analytical parameter sensor and electronics. The heat emitting resistor has a resistance that varies in response to temperature. The electrical parameter sensor is to sense an electrical parameter of the heat emitting resistor that is based on the resistance of the heat emitting resistor. The electronics determine a flow based on the sensed electrical parameter.

Abstract: A gas flow meter comprises a meter body, a tube, and a sensing unit. The sensing unit includes a base connected with one end of the tube; a speed transducer penetrating the base; a temperature transducer penetrating the base; a temperature compensator penetrating the base; and a microcontroller accommodated inside the meter body. The microcontroller is electrically connected with the speed transducer, the temperature transducer and the temperature compensator. The temperature transducer only functions to detect the temperature of the surrounding gas. The temperature compensator only functions to compensate the speed transducer for the temperature drop thereof. Each of them functions independently. Once the temperature of the speed transducer lowers, the temperature compensator directly compensates for the temperature drop, whereby the statistic error value is effectively decreased.

Abstract: A hydrogen leakage detector includes a sensor and a microcontroller. The sensor is sensitive to a concentration of hydrogen in air. A sensitive unit of the sensor is exposed directly to an in situ concentration of the hydrogen. The microcontroller is programmed to generate and output an analog signal corresponding to concentration information, based on a concentration measurement from the sensor, and to generate and output an analog signal indicating a correct operation of the detector.

Abstract: A portable therapeutic fluid delivery device with a flow detector comprising a heating element and two temperature sensors is presented. Upon activation of the heating element, a flow condition of the fluid inside the delivery tube is determined based on a signal provided by the temperature sensors. A temperature gradient within the therapeutic fluid is detected. The determined flow condition can be one of: air bubbles within the delivery tube, occlusion within the delivery tube, or leakage within the delivery tube. The device can have two parts, for example, a reusable part and a disposable part. Upon pairing of these parts, the heating element and the temperature sensors touch the delivery tube.

Abstract: The present invention provides a MEMS thermal flow sensor or meter for measuring the flow rate of a fluid without need for calibration of the flow sensor for that particular fluid. A response curve is determined by plotting the sensor output voltage against the volume flow rate divided by fluid thermal diffusivity for a calibration fluid of known thermal diffusivity, and storing response curve data in memory. A conversion factor is employed to provide a measure of correct flow rate of an unknown fluid. This conversion factor is derived from the ratio of the thermal time constant of the calibration fluid to the thermal time constant of the measured fluid, the time constants being measured at zero flow. These time constants are stored in memory. This conversion factor in conjunction with the response curve data is utilized by the processor to produce the correct flow rate.

Abstract: Embodiments provide a light emitting device package including a package body having a top-opened cavity disposed in at least a portion thereof, a first electrode layer and a second electrode layer electrically isolated from the package body with an insulating layer interposed therebetween, the first electrode layer and the second electrode layer being electrically isolated from each other at a bottom surface of the cavity, a light emitting device placed on the bottom surface of the cavity configured to emit light through the open region of the cavity, and a sensor placed on at least a portion of the package body at the outside of the cavity configured to measure output of the light emitting device.

Abstract: A method for compensating for changes in a property of water in a multiphase fluid during analysis of the multiphase fluid is provided. In one embodiment, the method includes providing a multiphase flow meter system configured to emit and detect nuclear radiation, to emit and detect microwave radiation, and to analyze a received multiphase fluid. The method can also include measuring a temperature and a microwave complex permittivity of the multiphase fluid. Further, the method includes compensating for changes in the property of water in the multiphase fluid during analysis of the multiphase fluid by using an empirical transformation between the fluid temperatures, microwave complex permittivities and nuclear mass attenuation coefficients for mixtures of different waters expected to be produced and received by the multiphase flow meter system. Additional systems, devices, and methods are also disclosed.

Abstract: A method is provided to operate a thermal anemometer flow meter to measure a property of a stream. The method includes measuring a first heat loss to the stream from operating at a first DeltaT above a temperature of the stream, measuring a second heat loss to the stream from operating at a second DeltaT above the temperature of the stream where the second DeltaT being greater than the first DeltaT. The method further includes determining the property of the stream based on the first and the second heat losses.

Abstract: A non-invasive thermal dispersion flow meter with chronometric monitor for fluid leak detection includes a heater, an ambient temperature sensor and a flow rate sensor which are configured to sense the temperature of a fluid in a conduit, and then monitor the flow of that fluid through the conduit. The fluid flow sensor is incorporated into a Wheatstone bridge circuit which is used to provide increased sensitivity to the outputs of the sensors. Based upon the ambient temperature sensor readings, the flow rate sensor and heater may be adjusted to optimize the operation of the system to detect leaks. An alternative embodiment utilizes a single sensor and separate heater which work together to determine heat propagation times which in turn is used to calculate flow rate.

Abstract: A flowmeter that improves a corrosion resistance is provided. The flowmeter includes a silicon substrate having a diaphragm where a heater is formed, an aluminum pad formed on a silicon substrate, an organic protective film laminated on the silicon substrate, and a mold resin that covers the silicon substrate. The diaphragm has an exposed portion exposed from the organic protective film, an adhesion surface high in adhesion property to the mold resin is laminated on the silicon substrate, and an adhesion film of the mold resin to the adhesion film is provided between the exposed portion and the aluminum pad.

Abstract: To reduce a signal variation of a bridge circuit connected with a temperature sensing resistor that is caused by a strain even when the strain is generated at a diaphragm portion of a substrate installed with a heater resistor and the temperature sensing resistor. In a thermal type flow rate resistor including a substrate, a diaphragm 13 formed at the substrate, and a heat generating resistor 2 and temperature detecting resistors 7 through 10 formed on the diaphragm for detecting a flow rate of a measured fluid by heating the heat generating resistor, strain detecting resistors 11 and 12 are formed on an upstream side and on a downstream side of a flow of the measured fluid relative to the heat generating resistor on the diaphragm, an amount of a strain generated on the diaphragm is detected by the strain detecting resistors, and a flow rate signal detected by the heat generating resistor and the temperature detecting resistors is compensated for the strain based on the detected amount of the strain.

Abstract: A sensor system has at least one first sensor element for measuring a first physical variable and a second sensor element for measuring a second physical variable. The first sensor element is part of an application-specific integrated circuit which, in addition to the first sensor element, has further electronic circuits. The second sensor element is arranged separately and outside the application-specific integrated circuit. The second sensor element is electrically connected to the application-specific integrated circuit via a first connection point. The application-specific integrated circuit is configurable via the first connection point and the measurement signal from the second sensor element can be read out via the first connection point.

Abstract: Airflow measuring apparatus compring: sub-passage that takes in part of flow of fluid flowing through an intake pipe; sensor element that is disposed in the sub-passage to measure the flow of fluid; a circuit part that converts the flow of fluid detected by the sensor element into an electric signal; connector part connected to the circuit part to output a signal externally; and casing that supports the sensor element and the circuit part, the sensor element being disposed in the intake pipe. The sensor element includes a cavity disposed at a semiconductor substrate, a diaphragm including a thin film part that covers the cavity. The sensor element on a lead frame have surfaces that are mold-packaged with resin so that a diaphragm of the sensor element and part of the lead frame are exposed. One hole is disposed at the lead frame for communication between the cavity and exterior.

Abstract: A method for detecting at least one flow property of a flowing fluid medium, at least one sensor element being used. The sensor element includes at least one heating element and at least two temperature measuring sensors. At least one first measured variable and at least one second measured variable, which is different from the first measured variable, are detected with the aid of the sensor element. The first measured variable and the second measured variable may be influenced by the flow property. At least one correction, in particular at least one correction factor and/or at least one correction vector, is generated from the first measured variable and the second measured variable. The flow property is determined from the first measured variable and the second measured variable under consideration of the correction.

Abstract: A constant temperature anemometer is disclosed. The anemometer includes electrically conductive pins including a first set of pins and a second set of pins. A conductor is coupled to the electrically coupled pins. A current source is configured to provide a current through the conductor between the first set of pins. A voltage sensor is configured to measure the voltage across the conductor between the second set of pins. The current source and voltage sensor are configured to maintain a constant resistance of the conductor between the first set of pins.

Abstract: To reduce a signal variation of a bridge circuit connected with a temperature sensing resistor that is caused by a strain even when the strain is generated at a diaphragm portion of a substrate installed with a heater resistor and the temperature sensing resistor. In a thermal type flow rate resistor including a substrate, a diaphragm 13 formed at the substrate, and a heat generating resistor 2 and temperature detecting resistors 7 through 10 formed on the diaphragm for detecting a flow rate of a measured fluid by heating the heat generating resistor, strain detecting resistors 11 and 12 are formed on an upstream side and on a downstream side of a flow of the measured fluid relative to the heat generating resistor on the diaphragm, an amount of a strain generated on the diaphragm is detected by the strain detecting resistors, and a flow rate signal detected by the heat generating resistor and the temperature detecting resistors is compensated for the strain based on the detected amount of the strain.

Abstract: A method of dispensing a volatile material comprises the steps of providing power to a volatile material diffuser having a diffusion element. The method further includes the step of operating the diffusion element for a randomly determined period of time, wherein the diffusion element is continuously activated and deactivated during the period of time at a randomly determined duty cycle.

Abstract: A constant temperature anemometer is disclosed. The anemometer includes electrically conductive pins including a first set of pins and a second set of pins. A conductor is coupled to the electrically coupled pins. A current source is configured to provide a current through the conductor between the first set of pins. A voltage sensor is configured to measure the voltage across the conductor between the second set of pins. The current source and voltage sensor are configured to maintain a constant resistance of the conductor between the first set of pins.

Abstract: A constant temperature hot-conductor anemometer includes a set of electrically conductive pins including a pair of inner pins and a pair of outer pins. A conductor is electrically and mechanically coupled to the pins. A current source is coupled to the inner pins. The current source is configured to provide a current through the conductor between the inner pins. A voltage sensor is coupled to the outer pins and configured to measure a voltage across the conductor between the outer pins. The current source and voltage sensor are configured to maintain a constant resistance of the conductor between the inner pins. In an example, a second set of pins, a second conductor and a second circuit are also used to measure dynamic temperature of a fluid and also to calibrate resistances at a known ambient temperature.

Abstract: The present invention provides a corrosion-resistant metal made sensor for fluid and a fluid supply device for which the sensor is employed. More specifically, the corrosion-resistant metal made sensor for fluid is equipped with a corrosion-resistant metal substrate, a mass flow rate sensor part comprising a corrosion resistant metal substrate, a thin film forming a temperature sensor and a heater mounted on the back face side of the fluid contacting surface of the corrosion-resistant metal substrate, and a pressure sensor part comprising a thin film forming a strain sensor element mounted on the back face side of the fluid contacting surface of the corrosion-resistant metal substrate, and the sensor is so constituted that the mass flow rate and pressure of the fluid are measured.

Abstract: A temperature compensating fluid flow sensing system is provided that comprises a resistance-based sensor element that is included in a constant voltage anemometer circuit configured to establish and maintain a command voltage across the first sensor element and to provide a constant voltage anemometer (CVA) output voltage corresponding to the resistance change in the first sensor element due to heat transfer between the first sensor element and the fluid. A controller is configured to establish the command voltage based on a desired overheat across the sensor and an actual overheat across the first sensor element. A power dissipation (PDR) module is configured to determine at least one fluid flow parameter and an actual overheat value based at least in part on the CVA output voltage and to transmit to the controller the actual overheat for use by the controller in updating the command voltage.

Abstract: A system is provided for controlling boundary layer shear stress adjacent a surface over which a fluid stream has been established. The system comprises a boundary layer control device adapted for altering at least one flow characteristic within a boundary layer in a selected region of the surface. The system further comprises a shear stress measurement system comprising a hot film sensor arrangement having at least one hot film sensor element appliable to the surface in the selected region. The at least one hot film sensor element is connected to an anemometer circuit configured to provide a sensor signal corresponding to heat transfer from the associated hot film sensor to the fluid stream. The system also comprises a control module in communication with the anemometer arrangement and the boundary layer control device. The control module is adapted for receiving and processing sensor signals signal from the anemometer circuit and for providing input signals to the boundary layer control device.

Abstract: A compensated flowmeter having a probe adapted to project into flowing media within a conduit. The probe includes a thermal dispersion sensor, and a compensating gas properties sensor contained within a no-flow chamber of the probe. The thermal flow sensor has active and reference sensor elements that responsively provide output signals relating to a flow rate of the media. The compensating gas properties sensor has compensating active and reference sensor elements that responsively provide output signals relating to the heat transfer of the media. A suitable processor is typically implemented for adjusting the measured flow rate detected by the thermal dispersion sensor to compensate for changes in heat transfer detected by the compensating gas properties sensor.

Abstract: According to the invention, to correct the curvature characteristic in output due to individual differences between frequency output type hot-wire flow meters, a frequency output type hot-wire flow meter includes a heating resistor disposed in the measurement target fluid and a voltage frequency conversion circuit for converting the air flow rate voltage signal that is proportional to the current flowing through the heating resistor. The voltage frequency conversion circuit converts the air flow rate voltage signal non-linearly to generate the output frequency.

Abstract: An intake passage upstream of a throttle valve is divided into a plurality of intake divided-flow conduits, and air flow meters are arranged in the respective intake divided-flow conduits. The throttle opening is obtained, and a throttle valve passing-through air amount, which is an amount of air passing through the throttle valve, is calculated on the basis of the throttle opening. Each air flow meter-detecting intake air amount, which is an intake air amount to be detected by the air flow meter, assuming that air flows through each intake divided-flow conduit by a part of the throttle valve passing-through air amount, the part being determined by a divided-flow ratio of the corresponding intake divided-flow conduit, is estimated, and a total value of the estimated air flow meter-detecting intake air amounts is then estimated. The engine is controlled on the basis of the total air flow meter-detecting intake air amount.

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: Methods and apparatus are provided for increasing the safety of a clogged or failed exhaust system. In accordance with a first embodiment, an apparatus is provided that includes (1) a tank adapted to contain a processing fluid; (2) an exhaust system coupled to the tank and adapted to exhaust a gas from the tank, the gas including a hazardous vapor of the processing fluid; (3) a sensor coupled to the exhaust system and adapted to detect a rate at which gas is exhausted from the tank; and (4) a fluid supply mechanism adapted to supply a diluting fluid to the tank so as to dilute the processing fluid contained by the tank if the rate at which gas is exhausted from the tank is less than a predetermined rate. Systems, methods and computer program products are provided in accordance with this and other embodiments.

Abstract: A device for measuring the flow-rate of gas in a duct, particularly for burners. The device includes a gas flow-rate sensor generating a first output signal proportional to the flow-rate detected, a temperature-compensation circuit receiving the first output signal and generating a second output signal proportional to the gas flow-rate detected by the sensor and independent of the temperature of the gas and/or the flow-rate sensor. The compensation circuit has a temperature sensor. The device also includes a calibration circuit receiving the second output signal. The calibration circuit generates a third output signal proportional to the gas flow-rate detected and independent of structural parameters of the flow-rate sensor and/or of the temperature sensor so that the third output signal is correlated with the flow-rate detected and independent of the temperature of the gas, the temperature of the flow-rate sensor, and the structural parameters of the flow-rate sensor.

Abstract: A gas flow determination method and a corresponding gas flow determination device. A sensor device including a diaphragm and a frame enclosing it is provided; a predetermined temperature profile is created on the diaphragm; the gas flow to be determined is directed over the diaphragm in a predetermined direction of flow; the change in the temperature profile caused by the gas flow is detected; and the gas flow is determined on the basis of the change thus detected. The temperature at a third location on the diaphragm upstream from the first location and optionally at a fourth location downstream from the second location is regulated at a value corresponding to the local value of the predetermined temperature profile. In this manner, the effect of soiling on the diaphragm may be minimized effectively.

Abstract: A gas flow meter having a gas flow detection circuit for detecting a current flowing through a resistor installed in a gas passage and a voltage generated across the resistor and outputting a voltage signal representing a gas flow passing through the gas passage; a noise reduction circuit for reducing external noise; and a digital adjusting circuit for digitally adjusting a signal representing the detected gas flow and outputting the adjusted signal; wherein a voltage signal based on the signal adjusted by the digital adjusting circuit is output.

Abstract: According to the invention, to correct the curvature characteristic in output due to individual difference between the frequency output type hot-wire flow meters, a frequency output type hot-wire flow meter comprises a heating resistor disposed in the measurement target fluid and a voltage frequency conversion circuit for converting the air flow rate voltage signal that is proportional to the current flowing through the heating resistor, wherein the voltage frequency conversion circuit converts the air flow rate voltage signal non-linearly to generate the output frequency.

Abstract: A system for compensation of contamination of a heated element in a heated element gas flow system in which the heated element becomes heated from an ambient temperature to an elevated temperature upon the application of electrical power to the heated element during a startup time period. The system includes a processing circuit having an input and an output. A voltage signal from the heated element is connected to the input of the processing circuit. The processing circuit reads a plurality of temporally spaced input signals as data from the processing circuit input during the startup time period. The processing circuit then computes the parameters of a transfer function corresponding to the data on its input. The processing circuit then calculates a contamination correction factor as a function of at least one parameter of the transfer function.

Abstract: A device for measuring the flow-rate of gas in a duct, particularly for burners. The device includes a gas flow-rate sensor generating a first output signal proportional to the flow-rate detected, a temperature-compensation circuit receiving the first output signal and generating a second output signal proportional to the gas flow-rate detected by the sensor and independent of the temperature of the gas and/or the flow-rate sensor. The compensation circuit has a temperature sensor. The device also includes a calibration circuit receiving the second output signal. The calibration circuit generates a third output signal proportional to the gas flow-rate detected and independent of structural parameters of the flow-rate sensor and/or of the temperature sensor so that the third output signal is correlated with the flow-rate detected and independent of the temperature of the gas, the temperature of the flow-rate sensor, and the structural parameters of the flow-rate sensor.

Abstract: The spirometer has a low thermal capacity. A circuit supplies power to the spirometer in pulses to heat the spirometer to body temperature. The circuit senses the temperature of the spirometer between intervals. The circuit can also be used in a calorimeter to measure the heat exchange during chemical reactions using the palladium hydrogen. The heating and sensing functions are performed by a single element to result in a small pocket sized device. The portability of the device increases its usefulness.

Abstract: When a micro-heater heats fluid using an external driving current, an upstream thermopile 8 detects the temperature of the fluid before it is heated to produce a first temperature detected signal and a downstream thermopile 9 detects the temperature of the fluid before it is heated to produce a second temperature detected signal. The flow rate is computed based on the difference signal between both detected signals. A right thermopile 11 and a left thermopile 13, which are arranged in a direction orthogonal to the flow direction of the fluid, detect the temperature of the fluid to produce a right temperature detected signal and a left temperature detected signal. The property of the fluid is computed on these right and left temperature detected signals. The flow rate is corrected on the basis of the property thus computed. The flow rate of an object fluid for measurement can be accurately measured by a flow sensor whose output characteristic varies when the kind or composition of the fluid changes.

Abstract: An air flow rate measuring apparatus generates a flow rate signal with a nonlinear characteristic from a flow rate detecting unit provided with a heat generating resistor and converts that into a signal with a linear characteristic by a linearizing circuit. Then, the flow rate signal is smoothed by a filter circuit to obtain a signal in which the measurement error due to a flow rate ripple is suppressed. Thereafter, the flow rate signal is again formed into a signal with a nonlinear characteristic by a nonlinear-form converting circuit to suppress resolution lowering due to analog-to-digital conversion.

Abstract: A hot wire gas flow rate sensor having a bridge circuit with a sensing resistor avoids saturation of the signal processing circuitry at high gas flow rates by increasing a bias signal to a differential amplifier in the signal processing circuitry in a step-like manner as the flow rate responsive signal to the differential amplifier from the sensing resistor increases. The differential input signal to the amplifier is thus maintained at a level that avoids saturation of the amplifier. Appropriate scaling is provided to the output circuitry of the sensor in accordance with changes in the bias signal so that the sensor output correctly indicates gas flow rates. Compensation is provided for changes in gas composition and when the sensing resistor is changed by determining the voltage drop across a first sensing resistor with a gas of known composition at a zero gas flow condition. The voltage drop across a second sensing resistor at the zero gas flow condition for the gas is also determined.

Abstract: A temperature regulator, circuit for an air-mass flow meter in which the temperature regulator circuit includes a bridge circuit one of whose bridge branches contains a temperature resistor of substantially higher resistance than a heating resistor in the other bridge branch. The resistance element of the temperature resistor normally requires a large amount of space on the sensor for this purpose. In order to reduce the size of the resistance element, a voltage divider is provided to reduce the input voltage applied to the temperature resistor. In order to maintain the bridge balance, additional circuit elements are provided in the other bridge branch containing the heating resistor.

Abstract: Gasmeter for determining a flow rate of gas within a channel is provided. The gasmeter includes a channel for passing through it a flow of gas along a first sensor and a chamber which is arranged for receiving and containing at substantially stand still gas from the channel and in which a second sensor is arranged. The sensors are heated during heating periods and subsequently let cooled down in cooling periods. The cooling rate of the sensors is determined and are used to calculate a value of the flow rate through the channel which is compensated for change of density of the gas.

Abstract: A heat-sensitive type flow sensor which can be manufactured by using discrete parts at low cost in a miniature size with high accuracy and reliability includes a correcting circuitry capable of compensating for a detected current indicating a flow rate of a fluid of concern and outputted from a flow rate detecting circuit.