405 results about "Mass flow sensor" patented technology

The flow sensor comprises a semiconductor device (1) on which a heat source and, symmetrically thereto, two temperature sensors are arranged. The semiconductor device (1) is arranged on an exterior side of a tube section (2), and a liquid, the flow velocity of which has to be measured, is led through the tube section (2). The temperature sensors and the heat source are in thermal contact with the exterior side of the tube section (2). It has been found that such an assembly allows to carry out flow measurements with high accuracy and sensitivity.

The mass flow rate sensor includes a waveguide disposed in a flow passage having a bluff body facing in an upstream direction. Waves are pulsed along the waveguide for interaction with the fluid. A receiver is coupled to the waveguide to detect a propagated wave and provides a first output signal proportional to the transit time of the propagated wave for determining fluid density. The receiver also provides a second output signal proportional to the shedding frequency of vortices from the waveguide to determine velocity. An electronics module calculates mass flow rate from the velocity times density times area of the flow passage and a constant. In other forms, the velocity is ascertained by transmitting an ultrasonic beam through the shedding vortices to determine vortex frequency which is proportional to velocity.

A mass flow controller includes a mass flow sensor and a calibrator configured to perform a self-calibration on the mass flow controller. The calibrator generates flow measurements that are used as “standards” and flow measurements from the mass flow sensor are correlated to flow measurements from the calibrator.

A mass flow sensor calibrator employs a variable-flow fluid source, a receptacle of known volume, and a pressure differentiator. The variable-flow fluid source supplies gas at varying rates to the mass flow sensor being calibrated and at proportional rates to a receptacle of known volume. A pressure differentiator computes the time derivative of gas flow into the receptacle of known volume and, from that, the actual flow into the receptacle. Given the actual flow, the proportionate flow into the mass flow sensor may be determined and the flow signal from the mass flow sensor correlated to the actual flow.

A high mass flow sensor device having a flow restrictor formed by a body having a generally cylindrical shape with an upstream end and a downstream end separated by a center portion having pressure taps proximate the junction of the ends with the center portion. Flow passes from upstream to downstream. The upstream end has a decreasing tapering inner surface for contact with the flow and the downstream end having an increasing tapering inner surface for contact with the flow. A center portion has radial and axial restrictor elements positioned forming axial openings in the path of flow through the center portion. The restrictor elements having tapered leading edges. One opening is formed by a central tube having a predetermined diameter and the remaining openings are radially extending members supporting the central tube, each of the radially extending members having substantially the same cross-sectional area as the central tube.

Provided is a control device for an internal combustion engine, which is provided to allow a throttle opening degree to be controlled in accordance with a target engine intake air flow quantity even during transitional operation. The actual cylinder intake air flow quantity calculating unit (21) calculates a response delay model for an intake system from a volumetric efficiency equivalent value (Kv) calculated from a rotational speed (Ne) of an engine (1) and an intake manifold pressure (Pim), an intake pipe volume (Vs), and a displacement (Vc) of each of cylinders (2), and calculates an actual cylinder intake air amount (Qcr) from an actual engine intake air amount (Qar) obtained from an air flow sensor (4) and the response delay model. The intake air flow quantity controlling unit (24) controls the throttle opening degree (TP) in accordance with the target engine intake air amount (Qat).

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.

The detector for monitoring decrease in air flow rate due to air filter clogging. It is based on combination of three essential components: the air flow sensor, a threshold detector and an indicator. The air flow sensor is built in form of a novel thermo-anemometer which contains a thermistor, a heating element, and a thermal insulator. Temperature of the sensor is maintained above the air temperature by a constant value by means of an electronic servo circuit. The threshold detector is implemented either in a hardware or software. A novel design of a thermo-anemometer (closely related to a hot wire anemometer) automatically compensates for variations in the air temperatures. The thermo-anemometer triggers the threshold circuit when air flow rate drops below a preset level. For reduction of power consumption, the detector may employ two additional sensors: one is for detection of the blower operation and the other is a presence detector to enable the alarm in presence of people to perceive the alarm. The device automatically calibrates itself upon installation of a new or cleaned air filter. The applications include residential and commercial air conditioners, air heaters, internal combustion engines, vacuum cleaners and other systems where air filters are employed.

A non-intrusive sensor for measuring mass flow of a medium flowing through a tube comprises: a probe having a predetermined length disposed along an external wall of the tube; a heater for heating the probe at a first point along the length thereof; a first temperature measuring device disposed at the first point for measuring a temperature of the probe and for generating a first signal Th representative thereof; a second temperature measuring device disposed at a second point along the length of the probe for measuring another temperature of the probe and for generating a second signal Tt representative thereof; a third temperature measuring device disposed along the external wall of the tube a distance away from the probe for measuring an ambient temperature and for generating a signal Ta representative thereof; and circuitry coupled to the first, second and third temperature measuring devices for generating a mass flow signal based on a ratio of temperature differential signals (Th−Ta) / (Tt−Ta). A counterpart method is also disclosed.

A yield monitor system is configured to determine how the calibration characteristics of a grain mass flow sensor on an individual combine are affected by grain moisture content and / or other grain parameters which can be measured instantaneously or periodically by the yield monitor system or its operator, or which can be observed by the operator, or which can be determined from other reference information, such as maps of where different grain varieties or hybrids were planted. Other systems, methods, and apparatuses are also provided.

A high mass-flow sensing apparatus and method of forming the same, comprising a flow tube bypassed in a flow path defined by a flow channel, through which a fluid flows. A flow sensor can be disposed in the flow tube for measuring a flow rate of the fluid in the flow channel. A set of narrow rectangular flow restrictors can be molded into the flow tube and adjacent to the flow sensor. Each flow restrictor can include several rectangular cutouts that are molded into upstream and / or downstream portions of the flow tube in order to limit the flow rate of the fluid across the flow sensor. The flow restrictors can laminarize the flow rate of the fluid in the flow tube and thereby reduce flow turbulence and lead to optimal sensing performance of the flow sensor.

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.

The current invention generally relates to Micro Electro Mechanical Systems (MEMS) thermal mass flow sensors for measuring the flow rate of a flowing fluid (gas / liquid) and the methods of manufacturing on single crystal silicon wafers. The said mass flow sensors have self-cleaning capability that is achieved via the modulation of the cavity of which the sensing elements locate on the top of the cavity that is made of a silicon nitride film; alternatively the sensing elements are fabricated on top of a binary silicon nitride / conductive polycrystalline silicon film under which is a porous silicon layer selective formed in a silicon substrate. Using polycrystalline silicon or the sensing elements as electrodes, an acoustic wave can be generated across the porous silicon layer which is also used for the thermal isolation of the sensing elements. The vibration or acoustic energy is effective to remove foreign materials deposited on top surface of the sensing elements that ensure the accuracy and enhance repeatability of the thermal mass flow sensing.

An instrument and method for measuring the volume of a hermetically sealed, variable volume, pressure conforming container. The instrument includes a needle, a vacuum pump, a mass flow rate sensor and an integrator. The needle has a lumen operable for sealingly perforating a container and thereby placing the lumen of the needle in fluid communication with a retention chamber defined by the container. The vacuum pump evacuates the gaseous content from the retention chamber through the lumen defined by the needle and past a mass flow rate sensor for sensing mass flow rates pulled through the lumen and transmitting corresponding mass flow rate signals over time to the integrator. The integrator is programmed to integrate the received mass flow rate signals over time through achievement of an evacuated retention chamber to generate a total mass value, and calculate a volume from the total mass value employing the Ideal Gas Law.

The invention relates to a high frequency Coriolis mass flowmeter digital signal processing system. The high frequency Coriolis mass flowmeter digital signal processing system comprises a DSP chip, a first signal conditioning module, a second signal conditioning module, a constant flow source, a Pt100 platinum resistor, a first ADC, a second ADC, a third ADC, an analog driver module, an external expansion FLASH module, a PWM output module, a current output module, an external expansion UART module, an HART modulation module, a man-machine interface module, a power down protection module and software. For signal processing of a high frequency Coriolis mass flow sensor, a TMS320C6726 chip with the strong operational capability and the high processing speed is used as a core processor, and the high frequency Coriolis mass flowmeter digital signal processing system is invented. Based on the zero-cross detection algorithm and DTFT algorithm, the high frequency Coriolis mass flowmeter digital signal processing system solves the problem that the algorithm cannot guarantee real-time performance after sampling frequency of high frequency sensor signals is increased.

The utility model discloses an electronic mass flow gas meter; an airtight cavity is arranged in the casing of the gas meter. The gas pipelines in the casing are divided into an independent gas inlet pipe, and a flow testing tube and gas outlet pipe, which are connected together. The gas inlet and outlet pipes are respectively connected with the gas outlet and inlet interfaces of the casing. The lower end of the flow testing tube is connected with the gas outlet pipe and horizontally suspended inside the casing. A main flow airway and a bypass airway are arranged in the flow testing tube; wherein, a by-passing device is arranged in the main flow airway and arranged between the two through holes for communicating the bypass airways. The cross-sectional area of the bypass airway is smaller than that of the main flow airway, and a signal sensing module of thermal mass flow sensors is arranged on the inner wall of the bypass airway for detection. The utility model can carry out mass flow measurement of the passing gas, and can prevent the dust in the gas from attaching to the sensing element, thus improving the measuring accuracy and service life of the gas meters.

The invention relates to the field of flow detection, and provides a Coriolis mass flow transmitter based on DSP, which comprises an amplifying filter circuit, an analog-to-digital converter 1, an analog-to-digital converter 2, a voltage reference source, a voltage follower, a current source, a difference amplifier, an analog-to-digital converter 3, a simulation driver module, a digital signal processor DSP minimum system, an expanding SRAM, an expanding EEPROM, a man-machine interface, 4-20mA current output and pulse output, a power module and a software. The simulation driver module stimulates a vibration exciter in the Coriolis mass flow transmitter so as to lead a flow tube to vibrate with natural frequency. Two magnetoelectric sensors positioned at two sides of the flow tube output two ways of sine-wave signals which are amplified and filtered by two ways of conditioning circuits with same parameter, then respectively and simultaneously sampled by two analog-to-digital converters with same model, and converted in digital value, and delivered to DSP by two multichannel buffered serial ports of the DSP. DSP adopts digital filter to eliminate the noise of the signals, is self-adaptive to a lattice notch filter to calculate the frequency, and then adopts the DTFT algorithm taking negative frequency into account to calculate to phase difference, thus obtaining the mass flow finally.

A mass flow rate sensor uses a Reynolds number correction function to compensate for errors in a bypass ratio of the sensor for all gases, based on the fact that all bypass errors are functions of Reynolds number. The sensor includes a sensor tube and a bypass tube dividing flow, wherein a bypass ratio of the sensor equals a total flow rate through the sensor divided by a flow rate through just the sensor tube. Heater elements heat an upstream portion and a downstream portion of the sensor tube, and a circuit is connected to the heater elements for producing a voltage based upon a difference in resistance between the heater elements. The voltage is calibrated based on known flow rates of a reference gas, and the flow rate through the sensor is based upon the calibrated voltage multiplied by a multi-gas correction function and a Reynolds number correction function.

The invention provides a method for correcting a relation of voltage and airflow speed of a mass flow sensor. The method comprises the following steps: step one, placing a first mass flow sensor and a second mass flow sensor at an air suction port and an exhalation port of an anesthesia machine respectively; step two, setting the anesthesia machine so that the air can enter only from the exhalation port and can be exhausted only from the air suction port; and step three, providing gas of different flow speeds to the exhalation port, and synchronously correcting respective relation of the voltage and the airflow speed of the first mass flow sensor and the second mass flow sensor according to the voltage value corresponding to the measured airflow flowing through the first mass flow sensor and the second mass flow sensor respectively. Therefore, compared with separate correction, by adopting the method of the invention, the correction can keep better consistency, and the correction precision can be improved; and simultaneously, the correction method is simplified, unnecessary workload is reduced, and the correction efficiency is improved.

To determine air mass flows, especially for controlling internal combustion engines, a hot-film air-mass sensor is provided, which may be used especially for sensing air mass flows in the intake tract of an internal combustion engine. The hot-film air-mass sensor has a sensor chip having a sensor frame and a sensor diaphragm having at least one heating element and at least two temperature sensors. Furthermore, the hot-film air-mass sensor has a chip carrier for mounting the sensor chip, as well as at least one additional heating element. The sensor chip is able to be heated up using the at least one additional heating element, which is inserted into the chip carrier. Compared to the usual devices, the hot-film air-mass sensor has a lower susceptibility to contamination, especially by oil films.

In various aspects of the invention a flow vortex suppression apparatus for use in an air intake duct having a mass air flow sensor is disclosed. The flow vortex suppression apparatus includes an air flow permeable fibrous vortex dispersive media installed into the air duct in a position upstream of the mass flow sensor and configured to occlude the air duct such that air flow in the duct is constrained to pass through the vortex dispersive media. The vortex dispersive media is configured and adapted to diffuse vortices and reduce air turbulence of an air stream entering the mass flow sensor, thereby reducing variations and noise in a flow measurement signal from the mass air flow sensor.

Mass air flow sensing for internal combustion engines. In one aspect, a sensor adaptor for use in an internal combustion engine includes an inlet housing including an approximately 90-degree elbow and directing air within the inlet housing to the internal combustion engine in an airflow direction. A mass air flow sensor is coupled to the housing at a location after the 90-degree elbow with respect to the airflow direction and senses the air flowing within the inlet housing.