400 results about "Mass flow sensor" patented technology

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 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).

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 T_h 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 T_t 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 T_a 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 (T_h−T_a)/(T_t−T_a). 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.

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 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.

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.