Abstract: An air flow measuring device includes a passage forming housing, a sensor housing, and a sensor part. An inner wall surface of the passage forming housing defines a measured passage. The passage forming housing includes a sensor attaching part. Measured air flows through the measured passage. The sensor housing is attached to the sensor attaching part. The sensor part is disposed on the sensor housing and measures a flow rate of the measured air flowing through the passage. The passage forming housing includes a guiding device for guiding the measured air, which flows along the inner wall surface of the passage forming housing on an upstream side of the sensor attaching part in a measured air flow direction, further toward a center of the passage than the inner wall surface of the passage forming housing on a downstream side of the sensor attaching part in the flow direction.

Abstract: A flow sensor may be formed by bonding a sensor chip formed with a flow rate detecting part and a flow path-forming member that is provided on the sensor chip and is formed with a flow path for a fluid flowing in the flow rate detecting part to each other on the upper surface of a substrate. The flow path-forming member may be formed by bonding a transparent first flow path forming member and a second flow path-forming member to each other. The first flow path forming member has a plate shape, and is provided with an inflow port and a outflow port for the fluid to be measured, and the second flow path forming member has a plate shape, and is provided with a through hole that forms the flow path along the flow of the fluid flowing along the flow rate detecting part.

Abstract: A first conductive line, through which a midpoint electric potential of a first series circuit of a bridge circuit is outputted, is branched from a first midpoint connection on a sensor chip. A second conductive line, through which a midpoint electric potential of a second series circuit of the bridge circuit is outputted, is branched from a second midpoint connection on the sensor chip. The output point of the midpoint electric potential of the first series circuit is provided at a midpoint between two temperature sensor resistors, and the first midpoint connection is provided on a center line of a heater resistor. The output point of the midpoint electric potential of the second series circuit is provided at a midpoint between two temperature sensor resistors, and the second midpoint connection is provided on the center line of the heater resistor.

Abstract: A digital fluid flow meter for measuring fluid flow past a surface on one side of a wall including first and second reduced thickness areas in the wall spaced from one another, a first detector having a first temperature sensitive element thermally coupled to the first reduced thickness area to provide thermal transfer between fluid in contact with the surface and the first detector, a second detector comprising a second temperature sensitive clement thermally coupled to the second reduced thickness area of said wall to provide thermal transfer between fluid in contact with the surface and the second detector. The digital fluid flow meter includes means for sensing the temperature of the first and second temperature sensitive elements, first and second heating elements for heating the respective temperature sensitive elements proximate to the first and second detectors, respectively.

Abstract: A thermal mass flowmeter with a metal-encapsulated sensor system is provided. The sensor system included at least one heating resistor having a platelet geometry, and a sensor cap surrounding the at least one heating resistor. At least one distal end area of the sensor cap is formed with a flat rectangular cross section corresponding to the platelet geometry of the heating resistor, such that the distal end area of the sensor cap surrounds the heating resistor closely with an accurate fit (e.g., with a predetermined gap therebetween).

Abstract: To provide an indication of whether airflow is separated, as opposed to other states of flow, over a surface, two or more adjacent sensors at a location on the surface each produce an analogue signal representative of airflow. The analogue signals are correlated with each other, and the degree of correlation indicates whether the airflow is in a separated state. The correlation may be carried out by comparing processed values of the analogue signals, and thresholding the comparison result.

Abstract: A device for detecting at least one property of a flowing fluid medium is proposed, in particular for detecting an air mass flow of an intake air mass. The device includes at least one sensor housing which may be at least partially introduced into the flowing fluid medium. At least one sensor element for detecting the property is accommodated within the sensor housing. At least one temperature sensor, which has at least one electric contact, in particular at least one contact wire, is furthermore accommodated in the sensor housing. At least one contact pad is furthermore accommodated in the sensor housing, the electric contact being electrically conductively connected to the contact pad at least one connecting point. The connecting point is protected against the fluid medium by at least one electrically insulating potting compound.

Abstract: Thermal, flow measuring device and method for operating a thermal, flow measuring device. The thermal, flow measuring device has a first sensor with a first heatable resistance thermometer and at least an additional, second sensor with a second heatable resistance thermometer; wherein a decision coefficient is calculated according to the formula DC=(PC1?PC2)/PC1, with PC1(t=t1)=P1,1(t1)/(T1,heated;actual(t=t1)?Tmedium;actual(t=t1)) and PC2(t=t2)=P2,2(t2)/(T2,heated;actual(t=t2)?Tmedium;actual(t=t2)), with P being the heating powers consumed by the corresponding resistance thermometers at the points in time t, and T being the temperature values; wherein the value of the decision coefficient indicates the flow direction of a measured medium in the measuring tube.

Abstract: A method for the manufacture of a sensor for a thermal flow measuring device, wherein the sensor has at least one housing with a first open end and a second open end. The first open end is securable in a sensor holder; and at least one resistance thermometer is inserted into the housing through the second open end of the housing and the second open end of the housing is closed. Cables for electrical contacting of the resistance thermometer lead out of the housing through the first open end of the housing.

Abstract: Methods and apparatus for determining flow rate of air or other gas through a conduit independently of conduit cross sectional area include providing apparatus for and measuring temperature of the air or other gas at a first position along the conduit; providing apparatus for and heating the air or other gas in the conduit of the location downstream from the first position by application of a known power level to the air or other gas in the conduit; providing apparatus for and measuring air or other gas temperature at a second position downstream of the heating position along the conduit; providing apparatus for and subtracting air or other gas temperature at the second position from air or other gas temperature at the first position to obtain a temperature difference and thereafter providing apparatus for and dividing power applied to heat the air or other gas by the product of the temperature difference and the specific heat of the air or other gas.

Abstract: An object of the invention is to provide a thermal air flowmeter which can reduce a detection error occurring during pulsating air flow due to a difference of response between rising and falling of detected flow or due to air flow dependence of response. A thermal air flowmeter 1 includes a heat-generating resistor 7 which heats liquid, a heating drive circuit 5 which causes current to flow in the heat-generating resistor 7 and thereby controls heating of the heat-generating resistor 7, and a temperature-sensitive resistor 9 which detects a temperature of the fluid heated by the heat-generating resistor 7. The thermal air flowmeter 1 detects a flow Q of the liquid based on the amount of heat of the liquid heated by the heat-generating resistor 7.

Abstract: Provided is a heating temperature adjustment circuit in a thermal flow meter capable of adjusting fluctuations of a heating temperature of a heat-generating resistor due to fluctuations of resistances with high accuracy and low cost. The thermal flow meter comprises: a heat-generating resistor that generates heat when a current flows therethrough; a first temperature measuring resistor, a second resistor, a third resistor, and a fourth resistor whose resistance values vary due to temperature; and a fixed resistance having a resistance temperature coefficient lower than that of the first temperature measuring resistor, and measuring a flow rate of a fluid by controlling the heating temperature of the heat-generating resistor.

Abstract: A flowmeter includes a flow sensor capable of measuring instantaneous flow rates of forward and backward flows of a fluid, smoothing means for smoothing the measured instantaneous flow rate, an integrating counter for integrating the smoothed flow rate and outputting an integrated flow rate, determination means for monitoring the smoothed flow rate to determine whether or not the fluid is fluctuating, an auxiliary counter for integrating, in place of the integrating counter, the smoothed flow rate while the fluid is judged to be fluctuating by the determination means and when fluctuation of the fluid is detected, and control means for adding an integrated flow rate held by the auxiliary counter to that held by the integrating counter when it is judged by the determination means that the fluid has begun to flow regularly, and causing the integrating counter to restart integrating the smoothed flow rate.

Abstract: An object of the invention is to provide a thermal air flowmeter which can reduce a detection error occurring during pulsating air flow due to a difference of response between rising and falling of detected flow or due to air flow dependence of response. A thermal air flowmeter 1 includes a heat-generating resistor 7 which heats liquid, a heating drive circuit 5 which causes current to flow in the heat-generating resistor 7 and thereby controls heating of the heat-generating resistor 7, and a temperature-sensitive resistor 9 which detects a temperature of the fluid heated by the heat-generating resistor 7. The thermal air flowmeter 1 detects a flow Q of the liquid based on the amount of heat of the liquid heated by the heat-generating resistor 7.

Abstract: To provide an indication of whether airflow is separated, as opposed to other states of flow, over a surface, two or more adjacent sensors at a location on the surface each produce an analogue signal representative of airflow. The analogue signals are correlated with each other, and the degree of correlation indicates whether the airflow is in a separated state. The correlation may be carried out by comparing processed values of the analogue signals, and thresholding the comparison result.

Abstract: A method of making a plurality of flow sensors is provided, each flow sensor having a substrate with a sensing element and flow channel aligned over the sensing element. The sensing element senses at least one property of a fluid. The flow channel is aligned by one or more guide elements formed in an alignment layer. The flow channel across the sensing area is accurately and precisely aligned due to the guide elements provided at the wafer-level, facilitating reliable, low-cost, and consistent results among multiple flow sensors. The flow sensor is adapted for use in harsh environments.

Abstract: A flowmeter includes a flow sensor capable of measuring instantaneous flow rates of forward and backward flows of a fluid, smoothing means for smoothing the measured instantaneous flow rate, an integrating counter for integrating the smoothed flow rate and outputting an integrated flow rate, determination means for monitoring the smoothed flow rate to determine whether or not the fluid is fluctuating, an auxiliary counter for integrating, in place of the integrating counter, the smoothed flow rate while the fluid is judged to be fluctuating by the determination means and when fluctuation of the fluid is detected, and control means for adding an integrated flow rate held by the auxiliary counter to that held by the integrating counter when it is judged by the determination means that the fluid has begun to flow regularly, and causing the integrating counter to restart integrating the smoothed flow rate.

Abstract: A mass flow sensor is manufactured by a process of carrying out a micro-machining process on an N or lightly doped P-type silicon substrate with orientation <100>. This mass flow sensor comprises a central thin-film heater and a pair of thin-film heat sensing elements, and a thermally isolated membrane for supporting the heater and the sensors out of contact with the substrate base. The mass flow sensor is arranged for integration on a same silicon substrate to form a one-dimensional or two-dimensional array in order to expand the dynamic measurement range. For each sensor, the thermally isolated membrane is formed by a process that includes a step of first depositing dielectric thin-film layers over the substrate and then performing a backside etching process on a bulk silicon with TMAH or KOH or carrying out a dry plasma etch until the bottom dielectric thin-film layer is exposed.

Abstract: A water flow rate sensing device for water ducts, comprising a thermal sensor (20) capable of measuring the flow by measuring the removal of heat by a heater from the water; an elongated support (9)/in particular, tubular, having the sensor (20) mounted at a free end thereof so that the support is inserted laterally with respect to the duct through a hole and cantilevered in order to keep the sensor in a central zone of the duct. The free end of the support comprises a lamina-shaped extension member. Furthermore, the device comprises means (5,7) for transmitting a measuring signal to a remote control unit. The invention comprises also a method for measuring the water flow.

Abstract: A thermal management system includes an airflow sensor that measures airflow in an air path inside an enclosure to be cooled, wherein the air path includes a filter and a fan. A controller is responsive to the airflow sensor for monitoring the rate of airflow inside the enclosure and determining the condition of the filter. In one embodiment, the airflow sensor is an active type sensor, such as a thermistor, disposed on circuit boards. In further embodiments, the airflow sensor is disposed proximate a tube through the filter.

Abstract: A gas measurement system comprising a probe (10), the probe (10) comprises a sensor circuit comprising a thermal dispersion sensor (23) and a reference thermistor (24), the thermal dispersion sensor and the reference thermistor are disposed within a shroud (20), the shroud partially enclosing the thermal dispersion sensor and the reference thermistor such that a gas flow through the shroud is substantially representative of the gas flow through a gas duct, the probe further comprises an elongate member (27) having an aerodynamic form, the shroud is mounted to the elongate member, the elongate member mountable within the gas duct, and a microprocessor for receiving a signal from the thermal dispersion sensor and the reference thermistor, the microprocessor calculating and displaying a gas velocity and gas temperature.

Abstract: A thermal flow detecting apparatus detects fluid flow in a main flow passage. A bypass passage portion is provided through which some fluid bypasses the main flow passage. A detecting element is provided in the bypass passage portion and arranged at a location eccentrically displaced from the center of a cross section of the bypass passage portion. A throttle portion is provided upstream of the eccentric detecting element in the bypass passage portion for throttling the cross section partially on a side of the detecting element.

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 cooling system for an indwelling heat exchange catheter includes a heat exchange bath that is configured to receive a conduit that carries saline to and from the catheter. A heating/cooling fluid is in the bath and exchanges heat with the saline. The heating/cooling fluid flows through a heat exchanger that includes a refrigerant and two variable speed DC compressor for removing heat from the refrigerant. A gear pump circulates the working fluid to and from the catheter and is removably engaged with a pump support platform.

Abstract: A high-accuracy EGR sensor is provided. A recirculation system is provided which controls the flow rate of EGR by use of the sensor. A thermal gas flowmeter includes a heating resistor disposed in a flow of gas to be measured for detecting the flow rate of the gas, and an external circuit electrically connected to the heating resistor for outputting a signal according to the flow rate of the gas to be measured using the heating resistor. The heating resistor is controlled to be heated at a temperature equal to or higher than a vapor film forming temperature for forming a vapor film.

Abstract: An integrated mass flow sensor is manufactured by a process of carrying out a micro-machining process on an N or P-type silicon substrate with orientation <100>. This mass flow sensor comprises an upstream thin-film heater, an downstream thin-film heater, and a pair of thin-film heat sensing elements, and a thermally isolated membrane for supporting the heaters and the sensors out of contact with the substrate base. This mass flow sensor is operated with three sets of circuits, a first circuit for measuring a flow rate in a first range of flow rates, a second circuit for measuring a flow rate in a second range of flow rates, and a third circuit in a differential configuration for measuring a flow rate in said first range of flow rates or said second range of flow rates, to significantly increase range of flow rate measurements and provide an optional for concentration measurement, while maintains a high degree of measurement accuracy.

Abstract: An air flow measuring instrument, comprising: an auxiliary passage 8 arranged inside a main passage through which fluid flows, a tabular member 5 on which a pattern of a heating resistor for measuring an air flow is provided on one face 5a, the tabular member being disposed inside the auxiliary passage so that the one face 5a on which the heating resistor pattern of the tabular member is provided is disposed along a flow of fluid inside the auxiliary passage 8, a heating resistor pattern-side fluid passage 8a portion formed so that the fluid flows between the face 5a and a passage-forming surface 8d of the auxiliary passage, and a back-surface 8b side fluid passage portion formed so that fluid flows between a face 5b on a side opposite to the face of the tabular member and the passage-forming surface of the auxiliary passage. Guidance portion 13 guiding dust that collides against the end portion to back-surface side fluid passage portion 8b side is provided on upstream-side end of tabular member.

Abstract: A solution metering apparatus having temperature sensing function comprises a substrate; a sensor layer consisting of a first sensing member, a second sensing member, and a temperature sensing member, where the first sensing member and the second sensing member respectively have in horizontal direction a plurality of sidewardly extended parallel strip lines that are alternately arranged, and the temperature sensing member is made of equivalent resistor material and disposed on one side surface of the substrate; and a protective layer overlying the sensor layer. The solution metering apparatus makes use of the physical characteristics of fluid as measured by the sensor layer, particularly its temperature sensing member to determine temperature change based on change in resistance value.

Abstract: A process transmitter includes a temperature responsive indicator to indicate an operating condition of the process transmitter. The operating condition may represent a level of a sensed process variable or an operating temperature of the process transmitter.

Abstract: A fluid flow rate sensor includes a detection circuit which generates a first signal corresponding to an output voltage of a bridge circuit, and a second signal corresponding to a fluid temperature. A control module can more accurately and quickly determine the fluid flow rate based on the first signal, the second signal and a look-up table. The look-up table includes a plurality of curves plotted according to data, indicating relationship among the fluid temperature, the output voltage and the fluid flow rate. The fluid flow rate sensor is inherently temperature compensated and has a shorter response time.

Abstract: A thermal flow meter corrects flow rate detection errors produced by vaporization of liquid phase components included in a gas to be measured. The thermal flow meter includes a correction circuit 500 that applies respectively different predetermined voltages to heating resistors consisting of first heating resistor Rh1 and second heating resistor Rh2 of a sensor element disposed in the gas to be measured to set a first temperature state and a second temperature state, calculates a first flow rate value Q1 of the gas to be measured in the first temperature state and a second flow rate value Q2 of the gas to be measured in the second temperature state, and calculates a flow rate correction value ?Q based on a ratio (Q1/Q2) between the first flow rate value and second flow rate value or a fourth-power value (Q1/Q2)4 of the ratio to correct a flow rate of the gas to be measured.

Abstract: A thermal flow rate sensor includes: a bridge circuit having a heat-generating resistor generating heat by receiving a supplied current, a heating element temperature detector having a resistance value varying in accordance with a temperature of the heat-generating resistor and a fluid temperature detector having a resistance value varying in accordance with a temperature of a fluid; a comparison portion supplying a digital output indicating a difference between voltages at intermediate points in the bridge circuit; a DA converter converting an output from the comparison portion to an analog signal and supplying the resultant signal to the heat-generating resistor as the current; and an output operation portion accumulating outputs from the comparison portion for a prescribed period to output a result of accumulation as a flow rate for the prescribed period, of the fluid which is an object of measurement.

Abstract: A flow sensor readily obtains high sensitivity without errors due to tilting. The flow sensor includes a flow channel having a pair of parallel portions and temperature sensing resistors for heating a fluid to a preset temperature. The temperature sensing resistors are disposed on parts of the parallel portions of the flow channel, to detect a fluid flow rate based on a change in temperature distribution of a flow channel due to a change in flow rate of the fluid flowing through the flow channel. The temperature sensing resistors include a first upstream temperature sensing resistor and a first downstream temperature sensing resistor that are disposed in a line on upstream and downstream sides of one of the parallel portions, respectively; and a second upstream temperature sensing resistor and a second downstream temperature sensing resistor that are disposed in a line on upstream and downstream sides of the other parallel portion, respectively.

Abstract: A honeycomb body includes ceramic walls all being entirely formed of printed layers forming channels through which a fluid can flow. The channels lie next to one another. At least one of at least one measuring sensor or electrically conductive mass forms a monolithic, unitary structure with one of the ceramic walls. Sensor material may be used as an alternative to ceramic material. A method of producing the honeycomb body is also provided.

Abstract: A mass flow sensor is manufactured by a process of carrying out a micro-machining process on an N or lightly doped P-type silicon substrate with orientation <100>. This mass flow sensor comprises a central thin-film heater and a pair of thin-film heat sensing elements, and a thermally isolated membrane for supporting the heater and the sensors out of contact with the substrate base. The mass flow sensor is arranged for integration on a same silicon substrate to form a one-dimensional or two-dimensional array in order to expand the dynamic measurement range. For each sensor, the thermally isolated membrane is formed by a process that includes a step of first depositing dielectric thin-film layers over the substrate and then performing a backside etching process on a bulk silicon with TMAH or KOH or carrying out a dry plasma etch until the bottom dielectric thin-film layer is exposed.

Abstract: A mass airflow sensor is disclosed that includes a heating element comprising an upstream side and a downstream side. Two resistive temperature sensors are placed on each side of the heating element and assuming mass air/liquid flows in a direction from left to right. The resistors are configured electrically in a Wheatstone bridge configuration. A regulated voltage is applied across the mass flow sensing, Wheatstone bridge. The regulated voltage is set high enough to produce self-heating effects on the sensing bridge. The central heating element will also be heated. As mass air/liquid flows across the temperature sensors and the heating element, the upstream (RU1 and RU2) resistors are cooled and the downstream (RD1 and RD2) resistors are heated. The resistance in the resistive temperature sensors changes with temperature creating a differential voltage signal proportional to the regulated voltage applied to the sensing Wheatstone bridge and rate of mass air/liquid flow.

Abstract: A device for measuring a volume flow, especially a tidal volume flow sensor, with a flow channel (1) and with a sensor element (6) arranged within the flow channel (1), is shown and described. The task of providing such a device, in which the sensor signal, which is generated by sensor elements arranged in the flow channel, remains as free as possible from distortions during the transmission to an evaluating unit, is accomplished by providing an internal circuit (3), which is arranged within the flow channel (1) and includes the sensor element (6). An external circuit (7) is arranged outside the flow channel (1). The external circuit (7) is designed for contactless, inductive coupling with the internal circuit (3) for supplying same with energy and for reading.

Abstract: A flow sensor that is designed to overcome problems of conventional flow sensors and can readily obtain high sensitivity without errors due to tilting. A flow sensor includes: a flow channel having a pair of parallel portions; and temperature sensing resistors for heating a fluid to a preset temperature, the temperature sensing resistors being disposed on parts of the parallel portions of the flow channel, to detect a fluid flow rate based on a change in temperature distribution of a flow channel due to a change in flow rate of the fluid flowing through the flow channel, the flow sensor comprising: a first upstream temperature sensing resistor and a first downstream temperature sensing resistor that are disposed in a line on upstream and downstream sides of one of the parallel portions, respectively; and a second upstream temperature sensing resistor and a second downstream temperature sensing resistor that are disposed in a line on upstream and downstream sides of the other parallel portion, respectively.

Abstract: A system and method for a low cost fluid flow sensor is described. One embodiment includes a fluid flow sensor comprising a first resistance temperature detector configured for generating a flow signal, wherein the flow signal is based on a fluid velocity, and wherein the first resistance temperature detector is configured for a fluid temperature range; a second resistance temperature detector configured for generating a temperature signal, wherein the temperature signal is based on a fluid temperature; and a controller coupled to the first resistance temperature detector and the second resistance temperature detector, the controller configured for receiving the flow signal and the temperature signal, wherein the controller takes a first controller action when the temperature signal is within a temperature signal range substantially representative of the fluid temperature range, and the flow signal is within a flow signal range, wherein the flow signal range is determined based on the temperature signal.

Abstract: A thermal mass flow measuring apparatus comprises a sheath having an interior surface and a protective exterior surface. A liquid material having a thermal conductivity greater than about 12 w/(m·° C.) is disposed within the sheath in contact with the interior surface of the sheath. A sensor element, such as a thin-film thermoresistive element or a wire-wound thermoresistive element is at least partially submerged in the liquid material. The liquid material, which is preferably liquid metal, decreases the overall thermal resistance between the outer surface of the sheath and the sensor element.

Abstract: A method of thermally coupling a flow tube or like component to a thermal sensor comprises bonding the component to the thermal sensor such that thermally conductive portions formed on the component are thermally coupled to corresponding sensing/heating elements disposed on the thermal sensor. The method can be employed to form a capillary mass flow sensor system. Thermally conductive portions, such as metal bands, can be formed on the outer surface of a capillary tube for bonding with corresponding resistive heat sensing and heating elements disposed on the substrate of a micro mass flow sensor. Bonding metal pads can be formed on the sensor surface preparatory to solder bonding the tube metal bands to the resistive sensing and heating elements.

Abstract: A thermal-type fluid flow sensor technology for measuring more precisely the temperature of the heater for an improved sensibility of detecting flow measurements. The thermal-type fluid flow sensor for measuring the air flow rate includes a heating resistive element formed on the semiconductor substrate through a first insulating layer, temperature-measuring resistive elements for heating resistive element for measuring the temperature of the heating resistive element, upstream and downstream temperature-measuring resistive elements for detecting the temperature of air on the upstream side and the downstream side of the air heated by the heating resistive element, and an air temperature measuring resistive element for measuring the temperature of the air heated by the heating resistive element, and at least the temperature-measuring resistive element for the heating resistive element is disposed in the upper layer or lower layer of the heating resistive element.

Abstract: An apparatus and method for fluid flow measurement are provided. The apparatus includes a first thermistor; a second thermistor; a first deflecting member configured to shield the first thermistor from fluid flowing in a first direction; a second deflecting member configured to shield the second thermistor from fluid flowing in a second direction where the second direction is substantially opposite the first direction; and a circuit in electrical communication with the first thermistor and the second thermistor. The circuit includes a comparator for comparing a first signal from the first thermistor to a second signal from the second thermistor. The comparator provides an output indicative of a direction of fluid flowing past the first thermistor and the second thermistor.

Abstract: The output characteristics of the sensing device or the control quantity of the sensing element can be adjusted by extracting an adjusting terminal in addition to a power source terminal, a ground terminal, an output terminal and the like outside a housing containing and protecting an electronic circuit. Further, by arranging the adjusting terminal inside a connector housing containing terminals such as the power source terminal, the ground terminal, the output terminal and the like, it is possible to prevent contact of foreign objects to the adjusting terminal and to water-proof the terminals for preventing corrosion since an associated connector is attached to the connector when the sensing device is actually used.

Abstract: The conductor wire surface for constituting a circuit formed by print or junction on a substrate formed from a composite member of ceramics, resin, and an inorganic member and from a resin member is coated with glass, resin, solder, or silver paste, thus the corrosion resistance can be improved, and a highly reliable electronic device for car use can be provided. Further, the probing portion necessary for adjustment of the resistance and characteristics and the mounting portion for mounting parts are formed in a shape having no corners at 90° or less, for example, in a circular shape, in an elliptical shape, or in a shape that the corners of a tetragon are rounded (R) or chamfered (C).

Abstract: A thermal type gas flow measuring instrument measures gas flow with high precision by accurately correcting changes in radiation heat characteristics of a heating resistor due to contamination. The instrument comprises a second heating resistor 30 whose resistance value, which changes if contaminated, is calculated by measuring the terminal voltage thereof by calculating means 32, and the calculated value is compared with a temperature detected by a temperature detecting element 31. Based on the result of comparison, the level of contamination of the second heating resistor 30 is determined. The second heating resistor 30 and the first heating resistor 3 are disposed in similar environments such that their levels of contamination can be considered equal. Based on the level of contamination calculated from the result of comparison, a correction value is calculated and the output of the first heating resistor 3 is corrected in accordance with the correction value.

Abstract: An airflow sensor system for monitoring air inlet airflow and air outlet airflow of a vacuum cleaner is provided according to an embodiment of the invention. The airflow sensor system includes a vacuum cleaner air duct, a bypass tube connected to the air duct, and an airflow sensor positioned at least partially in the bypass tube. The airflow sensor is configured to generate a normal voltage differential range when the bypass tube airflow is within a predetermined normal airflow range, configured to generate an input blockage voltage differential range when the bypass tube airflow is greater than the predetermined normal airflow range, and further configured to generate an output blockage voltage differential range when the bypass tube airflow is less than the predetermined normal airflow range.

Abstract: A circuit for measuring the mass air flow rate through a duct is disclosed. The circuit includes a bridge circuit, a first amplifier, an oscillator, a comparator and a switch. The bridge circuit has a plurality of resistors arranged to output first and second bridge voltage signals. The first amplifier circuit receives the first and second bridge voltage signals and generates a differential bridge voltage signal. The oscillator provides an oscillating control signal. The comparator is in communication with the first amplifier circuit and the oscillator for comparing the differential bridge voltage signal to the oscillating signal to generate a pulse width modulated differential bridge voltage signal. The switch is in communication with the bridge circuit and the comparator. The switch selectively provides a power voltage signal to the bridge circuit at a frequency corresponding to the pulse width modulated differential bridge voltage signal.

Abstract: A thermistor is pulsed with energy, and a time constant of decay of temperature is calculated based on measured resistance of the thermistor over a number of known intervals. The time constant is representative of the mass air flow. The ambient air temperature may be found without waiting for the thermistor to reach the ambient air temperature.

Abstract: A device for determining flow parameters, particularly the temperature and flow speed and changes therein, in a fluid flow for monitoring and a fire recognition or oxygen measuring device provided with such a device are provided. A slow or sudden blockage, crack or break in a pipe system of an aspirative fire recognition device is recognized by a measurement technique, whereby an air flow sensor, operated with a constant excess temperature, is combined with a regulation algorithm, running in a microprocessor, for monitoring pipe system fluid flow or flow resistance. The required resistance of the air flow sensor can thus be calculated by an exact sensor calibration curve and a precise control loop formed. The measured values recorded by the air flow sensor are extremely reliable, such that changes in condition for the flow parameters provide information about the state of the pipe system or the intake system.