Abstract: A spray system and method for testing the flow rate of individual nozzles in the spray system are disclosed. The spray system can include a spray tank for holding a fluid to be sprayed, a pump in fluid communication with the spray tank, a manifold in fluid communication with the pump, a plurality of spray nozzles in fluid communication with the manifold, a main flow meter located in a first branch line in fluid communication with the pump and the manifold, a nozzle check flow meter located in a second branch line in fluid communication with the pump and the manifold, and a valve assembly for operating the spray system between a normal operation mode and a nozzle test mode, wherein in the normal operation mode, the valve assembly directs flow to the main flow meter, wherein in the nozzle test mode, the valve assembly directs flow to the nozzle check flow meter.

Abstract: A concentration sensor assembly can include a vaporization chamber having a compound. The concentration sensor assembly may include a first flow path coupled to the vaporization chamber. The first flow path may direct a first gas to the vaporization chamber. A second flow path can direct a second gas out of the vaporization chamber. The second gas can include the compound and the first gas. A first sensor is disposed along the first flow path. The first sensor measures first data indicative of a first mass flow rate of the first gas. A second sensor is disposed along the second flow path. The second sensor measure second data indicative of a second mass flow rate of the second gas. A computing device may determine a concentration of the vaporizable substance within the second gas based on the first data and the second data.

Abstract: A method for controlling a flow of one or more fluids from a formation into a production tubing, includes measuring fluid properties of the one or more fluids passing through one or more fluidic oscillators of a flowmeter device disposed on the production tubing, adjusting the flow in a flow area based on the fluid properties through an inflow control device coupled to the production tubing and is in fluid communication with the flow meter device, and controlling, in response to change in the fluid properties, actuation of the inflow control device to adjust the flow by a controller coupled to the inflow control device.

Abstract: A process is described that includes flowing a carrier fluid through a transfer line, feeding polymer pellets into the transfer line at a feed location, measuring a first pressure value of the carrier fluid at a location in the transfer line upstream of the feed location, measuring a second pressure value of the carrier fluid and polymer pellets at a downstream location in the transfer line which is downstream of the feed location, and determining a mass flow rate of the polymer pellets flowing in the transfer line based on a differential pressure between the first pressure value and the second pressure value.

Abstract: Calibration of a valve in a vacuum system and providing a diagnostic indication in the vacuum system using the calibration includes measuring conductance of the valve as a function of angular valve position and generating a conductance calibration map or function for use during operation of the valve. An actual angular valve position is set based on the received set point angular valve position and a difference between the measured valve conductance and a predefined metric of conductance versus angular valve position. An actual system conductance and a difference between the actual system conductance and a reference system conductance for the system are determined. The diagnostic indication of a fault in the system is generated based on the actual angular valve position of the valve and the difference between the actual system conductance and the reference system conductance for the system.

Abstract: A cleaning liquid supply device for supplying a cleaning device with cleaning liquid includes a chemical liquid inlet portion and a dilution water inlet portion, a first chemical liquid control unit fluidically connected to the chemical liquid inlet portion and the dilution water inlet portion, and a second chemical liquid control unit fluidically connected to the chemical liquid inlet portion and the dilution water inlet portion. The first chemical liquid control unit includes a first chemical-liquid-flow-rate control unit, a first dilution-water-flow-rate control unit, and a first mixing portion. The second chemical liquid control unit includes a second chemical-liquid-flow-rate control unit, a second dilution-water-flow-rate control unit, and a second mixing portion.

Abstract: A gas meter having a sensor module and at least one bypass module is described herein. In an example of the gas meter, an enclosure defines an interior cavity within which a manifold may be configured to include a sensor module connector, at least one bypass module connector, and an exhaust port. A sensor module may be connected to the sensor module connector of the manifold and may measure a flowrate through the sensor module and into the manifold. A bypass module may be connected to the bypass module connector of the manifold to bypass gas around the sensor module. A processor may be used to compute a gas flowrate through the meter using inputs including the measured flowrate and data based on the measured flowrate to adjust for gas that bypassed the sensor module.

Abstract: A flow measurement system includes two or more flow sensors that may operate simultaneously and a plurality of connected flow paths for flow of fluids. Each flow sensor is positioned along a different flow path of the plurality of connected flow paths and includes at least one flow tube and a support that clamps the flow tube. The flow tube of each flow sensor has a different resonant frequency so that cross-talk between the flow sensors can be reduced or eliminated. In some embodiments, the flow tube of each flow sensor has a different tube length, wall thickness, material, and/or weight. The flow measurement system can also include one or more pumps for pumping fluid into the flow sensors and a dampener arranged between a pump and a corresponding flow sensor for mitigating interference on the flow sensor from operation of the pump.

Abstract: A technique facilitates monitoring fluid phases of a multiphase flow during, for example, well fluid production operations. According to an embodiment, data may be obtained from devices, such as chokes and pressure sensors. This data is then processed to identify phases of the multiphase well fluid flow. The use of data from such well related devices effectively establishes a virtual multiphase flowmeter. However, the output from the virtual multiphase flowmeter may be calibrated periodically by taking measurements from an actual multiphase flowmeter. In some embodiments, the data from a plurality of flow meters having differing physical operating principles may be correlated in a manner to obtain additional parameters related to the multiphase well fluid flow.

Abstract: Systems and methods for finding and solving problems with wet gas venturi meters in one or more gas well sites include one or more gas well sites configured to supply gas to a gas plant, each gas well site comprising a gas well connected to a piping, one or more valves installed on the piping, one or more pressure sensors, one or more temperature sensors, one or more venturi meters configured to measure a differential pressure of the gas in the piping, and one or more programmable logic controllers configured to receive the measured data from the pressure sensors, temperature sensors, and the venturi meters, receive a plurality of dimensions of the one or more venturi meters, receive a plurality of fluid properties values and, determine a first gas rate and first condensate rate for each of the well sites.

Abstract: Method and apparatus relating to ultrasound flow probes Measurement of time of flight of ultrasound pulses comprises: transmitting the pulses across a fluid flow; detecting a waveform (200) of the pulses, generating a cross-correlation between the waveform (200) and a tone (210) and identifying a plurality of peaks (220) in the cross-correlation; fitting a curve template (310) to the waveform at locations (300) corresponding to the peaks (220) and identifying the location (330) of the minimum error; performing a further cross-correlation (420) between the waveform (200) and the tone (210) over only a portion of the waveform (200) containing the minimum error location (330); and determining the temporal location corresponding to the maximum (430) of the further cross-correlation (430).

Abstract: An engine emissions test system according to the principles of the present disclosure includes a sampling conduit, at least one sample bag, a read circuit, and a fill circuit. The sampling conduit is configured to receive exhaust from an engine. The at least one sample bag is configured to store a sample of exhaust. The read circuit is configured to communicate the stored sample of exhaust between the at least one sample bag and an analyzer. The fill circuit includes a fill gas line configured to provide a fill gas to be mixed with the sample of exhaust. The fill gas line extends between a fill gas source and the read circuit.

Abstract: A method and device for determining a velocity of a flowing medium that allows an as high as possible measuring accuracy without requiring a complicated measuring construction is achieved in that a vortex is generated in the medium and an electromagnetic signal is emitted into the medium. Then, the permittivity of the medium is determined and the velocity of the medium is determined using the permittivity measurement.

Abstract: This invention is to improve procedures of maintenance of a fluid measurement system having a fluid measurement device and a control device. The fluid measurement system has a fluid measurement device and a control device to control the fluid measurement device, and the fluid measurement device comprises a fluid sensor and a related data store part configured to store fluid calculation related data for calculation of one or more fluid parameters with measurement data obtained by the fluid sensor, and the control device obtains the fluid calculation related data from the related data store part and calculates the one or more fluid parameters with the measurement data of the fluid sensor and the fluid calculation related data.

Abstract: An example system includes a separator that accepts and separates a multiphase flowback effluent stream into a plurality of secondary streams. A first sensor assembly monitors the multiphase flowback effluent stream and generates a first signal corresponding to at least one characteristic of the multiphase flowback effluent stream. A second sensor assembly monitors one of the plurality of secondary streams and generates a second signal corresponding to at least one characteristic of the one of the plurality of secondary streams. A signal processor receives the first and second signals and determines a mass flow rate of a substance present in both the multiphase flowback effluent stream and the one of the plurality of secondary streams.

Abstract: The cloud-based water quality and leak monitoring system contains a server device on the Internet and a pipe device containing a main pipe and an auxiliary pipe connected to the main pipe in parallel. The pipe device further contains a pH detection element, a water pressure detection element, a turbidity detection element, and a flowmeter element. Various data from these elements is transmitted to the server device via WiFi or 4G wireless communications. The server device stores the various data so that a user is able to access, download, and view these data using a computer or a mobile device.

Abstract: A method and system for measuring a flow profile in a portion of a flow path in a turbine engine is provided. The system includes a mass flow sensor assembly having a plurality of hot wire mass flow sensors, the mass flow sensor assembly disposed in the portion of the flow path at a location where the flow profile is to be measured. The system also includes a controller that converts signals from the temperature sensor, the pressure sensor and the plurality of hot wire mass flow sensors to flow profile measurements.

Abstract: A system and method of calibrating a meter of a product distribution machine, such as an agricultural air seeder is shown. The system uses one or both of optical and mass flow sensors to measure the product flow rate. The sensors are used to measure mass flow rate during a calibration process while the machine is in use. To improve sensor accuracy during the calibration process, the meter speed is changed to change the product flow rate to a rate at which the sensor accuracy is increased.

Abstract: Information in a data store may be efficiently accessed to perform boundary reading processing. In one example, register readings of one or more register channels that are linked to one or more interval channels may be retrieved from the data store to determine whether or not a boundary reading of a time span is missing. If a boundary reading is missing, but a proximate register reading exists, the boundary reading may be estimated from the proximate register reading and at least one interval reading.

Abstract: A regional security system includes a control panel which can receive one or more delay parameters, associated with a type of sensor or detector, or a portion of a region being monitored. The delay parameters can be stored in a programmable storage unit. When an alarm indicator has been received from one of the sensors or detectors, an alarm indicating message along with an associated, programmed and pre-stored delay can be forwarded to a central station. If the system is disarmed before the delay interval has terminated, a cancel message can be sent to the central station.

Abstract: The invention relates to a fuel management system for a vehicle. The fuel management system includes a fill-up sensor located at an inlet of a fuel tank of the vehicle, for determining the volume of fuel flowing into the fuel tank, a fuel supply sensor located in a fuel line between the fuel tank and an engine of the vehicle, for determining the volume of fuel flowing to the engine of the vehicle and a return line sensor located in the fuel return line of the vehicle, for determining the volume of fuel returning to the fuel tank. The system further includes a controller in communication with the fill-up sensor, fuel supply sensor and return line sensor, for collecting data from the sensors, calculating whether there is a fuel deviation between the amount of fuel entering the fuel tank and consumed by the vehicle, and generating fuel deviation events.

Abstract: An insert apparatus for installing a transducer assembly in a sensor port of a flow cell is disclosed. The transducer assembly is installed in the cavity of the insert body without the use of glues or adhesives to bond the transducer assembly to the cavity.

Abstract: Provided is a raw material gas supply device which includes: a raw material container; a carrier gas supply unit configured to supply a carrier gas into the container via a carrier gas flow path; a first flow rate measurement unit configured to measure a flow rate of the carrier gas flowing therethrough and output the same as a first flow rate measurement value; a raw material gas supply path configured to supply a raw material gas containing a vaporized raw material into a film forming apparatus; a second flow rate measurement unit configured to measure a flow rate of the raw material gas flowing therethrough and output the same as a second flow rate measurement value; and a flow rate calculation unit configured to calculate a difference between the first and second flow rate measurement values and to convert the difference into a vaporization flow rate of the raw material.

Abstract: The present invention relates to a method for carrying out measurement of gas distribution in an ESP and also relates to a gas distribution measurement system for measurement of gas velocities in an ESP. The gas distribution system (8) comprises probe carrier (9) that moves in the ESP 1, air velocity probe (10) that record the air velocity readings and a display controller (11).

Abstract: A method and system provides for monitoring, troubleshooting and acquiring diagnostics information from an aspirating dispensing system (10). The dispensing system (10) uses an aspirator (12) with a plurality of liquid inlet ports and a flow meter (30) connected in liquid communication with at least one of the liquid inlet ports and a liquid source. The system monitors, troubleshoots and acquires diagnostics information from one or more components of the dispensing system by monitoring operation of the flow meter (30).

Abstract: The purpose of the invention is to supply an apparatus and method for measuring the three-dimensional velocity and void fraction in gas-liquid two-phase flows. It mainly includes a measuring probe (1), four pressure sensors (18), three electrodes (3), a back-flushing system (19), a pressure-based electrode couple selection system (14), and a data acquisition and analysis system (28).

Abstract: An apparatus, method and system providing for calibration and/or control of a liquid dispensing system is disclosed. The hand-held calibration auditing tool includes a flow meter (36-37) with inlets adapted for quick connection to one or more liquid inputs and/or liquid outputs of a liquid dispensing system (10). A sensor (94-95) having a data output of liquid flow information for a liquid input to the dispensing system (10) is operably connected to a controller (12) to receive the liquid flow information for the liquid input. The controller (12) provides a dilution rate and other liquid flow information for a liquid product input to a dispenser. The tool may include any number of flow meters, and may also include a flow meter connected to an outlet of a dispenser (22) for providing flow information.

Abstract: A control method for controlling a wastewater network, said network including actuators suitable for influencing the flow rates of water in the network, with the behavior of the actuator depending on setpoints, the method comprising: a step of selecting a rain type from a list of predetermined rain types, as a function of forecast or measured rain; a step of selecting a set of setpoints from a list of predetermined setpoints, as a function of the selected rain type; and a step of sending the setpoints of the selected set of setpoints to said actuators. The method further comprises a step of obtaining first state information representative of the current state of the network, said set of setpoints being selected from the list of predetermined sets of setpoints as a function of the selected rain type and as a function of the first state information.

Abstract: A plasma processing apparatus includes at least three gas supply lines connected to a process chamber in parallel to allow a gas to flow therethrough, and at least three flow-rate controllers provided on the gas supply lines to detect the flow rate of the gas flowing through each of the flow-rate controllers to control the flow rate to a set value and a diagnosis method. The apparatus has a function of splitting and supplying a gas controlled to a predetermined flow rate by the third flow-rate controller, to a first flow-rate controller for the smallest detectable range of the three flow-rate controllers and to a second flow-rate controller, in order to test the operation of the control of the flow rate of the first flow-rate controller, based on the value obtained from the flow rate of the gas flowing through the second flow-rate controller and the predetermined flow rate.

Abstract: A bracket system and method to retrofit a subsurface water meter enclosure with a mount so as to provide secure positioning means suitable for components related to a water meter such as water-usage monitoring equipment. The system is only removable from the water meter enclosure via disassembling the water meter enclosure.

Abstract: A fuel valve for a gas turbine engine includes a passageway configured to direct a fuel to the engine and a flow restriction positioned in the passageway. The fuel valve may also include a first pressure sensor coupled to the passageway upstream of the restriction through an upstream port, and a second pressure sensor coupled to the passageway downstream of the restriction through a downstream port. The fuel valve may further include a third pressure sensor coupled to the upstream port through a first branch port, and a fourth pressure sensor coupled to the downstream port through a second branch port.

Abstract: The invention relates to a fluid meter (27) comprising a housing (28) defining at least one crankcase (29) and two cylinders (25, 26), a crankshaft (11) disposed in the crankcase (29), two pistons (3, 4) respectively mounted in the cylinders (25, 26) for reciprocal movement, a first connecting rod (12) connected to one of the pistons (3) and to the crankshaft (11) for rotating the crankshaft (11) in response to the movement of the one piston (3), and a second connecting rod (13) connected to the other piston (4) and to the crankshaft (11) for rotating the crankshaft (11) in response to the movement of the other piston (4), wherein the first and second connecting rods (12, 13) have yoke slots (16, 17) for receiving a crank pin (19) radially offset from the crankshaft (11).

Abstract: A fluid meter (27) comprising a housing (28) defining at least one crankcase (29) and two cylinders (25, 26), a crankshaft (11) disposed in the crankcase (29), two pistons (3, 4) respectively mounted in the cylinders (25, 26) for reciprocal movement, a first connecting rod (12) connected to one of the pistons (3) and to the crankshaft (11) for rotating the crankshaft (11) in response to the movement of the one piston (3), and a second connecting rod (13) connected to the other piston (4) and to the crankshaft (11) for rotating the crankshaft (11) in response to the movement of the other piston (4), wherein the first and second connecting rods (12, 13) have yoke slots (16, 17) with a circumferential periphery (62) for receiving a crank pin (19) radially offset from the crankshaft (11).

Abstract: A fluid flow meter estimates the velocity of water or another fluid flowing through pipe by comparing measurements of the water velocity to one or more pre-determined templates. The fluid flow meter may collect measurement signals from one or more flow sensors (e.g., ultrasonic transducers), estimate the fluid velocity or flow rate by comparing the measurement signals to the template(s), and either store the comparison results in local memory, transmit the results to a remote memory or server, or both. In some embodiments, the fluid flow meter transmits the results to a server via a wireless interface (e.g., a Zigbee, Bluetooth, or Wi-fi interface). The transducers and processing system can be powered by a battery, a power line, or, for manifolds installed outdoors, a solar cell. Example transducers and processing systems may also have a passive wake-up feature for power reduction; that is, they may only draw power when water or another fluid flows through the pipe.

Abstract: Appurtenances added to a pipe mitigate the effects of upstream valves, sluice gates or pipe elbows to condition the pipe flow for accurate flow rate detection by a reverse propeller meter. Further appurtenances allow the reverse propeller meter to be used in extreme debris situations such as weeds, vines and moss present in many canal systems. The system provides an electronic signal that indicates flow rate and accumulated flow volume, or the signal can be transmit to a central headquarters for remote gate control or canal automation.

Abstract: The present invention relates to a method for carrying out measurement of gas distribution in an ESP and also relates to a gas distribution measurement system for measurement of gas velocities in an ESP. The gas distribution system (8) comprises probe carrier (9) that moves in the ESP 1, air velocity probe (10) that record the air velocity readings and a display controller (11).

Abstract: A gas appliance monitoring apparatus includes a flow rate measurement unit for measuring the gas flow rate, a gas shut-off valve for shutting off a gas flow path at the abnormal time, an information storage unit for storing measurement results of the flow rate measurement unit, a wireless module for transmitting and receiving information, and a communication switch unit for switching a communication frequency band. The wireless module is integrated with a control circuit board forming the flow rate measurement unit and is housed in a gas meter. The wireless module has at least a communication frequency band with a base station and a communication frequency band with a plurality of gas appliances, and transmits an operation start signal detected by a specific gas appliance as appliance information using an appliance wireless module. The continuous use time of the specific appliance is detected or is changed based on the information.

Abstract: A remote water meter monitoring system is provided. A mesh network-type transceiver unit is coupled to a water meter housing having a water counting mechanism inside to transmit water consumption information as well as other sensor information, such as backflow detection, water pressure, and water metrics (e.g., residual chlorine and temperature) to a central server system via a bridge device and a corresponding mesh network. Mechanical energy from the water flowing through the water meter housing is converted to electrical energy via an energy conversion unit. An electrically powered shut off valve is remote addressable via the transceiver unit.

Abstract: The present invention refers to a flow distribution measuring system comprising a sensor matrix adapted to measure the flow distribution of permeate passing through a membrane filtration arrangement and also refers to a cap comprising such a sensor matrix; wherein the cap is adapted to be affixed to a membrane filtration arrangement. The present invention further refers to methods of using the flow distribution measuring system and the cap.

Abstract: A method and apparatus for determining a level of stratification of a multiphase fluid flow passing through a pipe is provided. The method includes, and the apparatus is operable to perform, the steps of: 1) determining a flow velocity of the multiphase fluid flow passing through a first radial region of the pipe; 2) determining a flow velocity of a portion of the multiphase fluid flow passing within a second radial region of the pipe, wherein the second radial region is above the first radial region; and 3) comparing the flow velocity from the first radial region and flow velocity from the second radial region to determine information indicative of the stratification of the multiphase fluid flow.

Abstract: The application is directed to methods, systems, procedures, networks and storage apparatus used to conduct conversions of data using remote conversion servers. In one embodiment of the present invention, recent query results may be stored and then used to solve subsequent conversions rather than querying a remote conversion server when the same conversion was previously completed. A counter may be referenced to determine if too much time has passed since the original query was stored in the buffer and, if too much time has passed, the buffer may be cleared and the remote conversion server may be queried to convert the pending data. The resulting conversion may be stored for subsequent use.

Abstract: The invention relates to a meter box for housing a utility meter and configured for associating a customer service line to a utility service line. The meter box may be configured to fit within an existing meter box and may be configured with side sections in a telescopic arrangement. Flow control components at an input of the meter box prevent backflow. The meter box comprises an electronic module that includes a variety of selectable features including datalogging, AMR, environmental monitoring, and resource monitoring. A remote monitor is provided for allowing a customer to view selected data including consumption data, pressure, pH, temperature, warnings, remote turnoff, and provide secured bill paying services. Imaging/audio components provide visual and audio data which may include an image of an analog readout for a meter register, images of the metering environment, and sound data for metering environment.

Abstract: The invention relates to a method and arrangement for measuring at least one physical magnitude, such as temperature, flow or pressure of the cooling fluid flowing in an individual cooling element cycle (3) of a cooling element (1) in a metallurgical furnace. The arrangement includes a supply header (2) for distributing the cooling fluid and for feeding it to the cooling element cycles (3) of the cooling elements (1), and a collection header (4) for collecting and receiving cooling fluid from the cooling element cycles (3) of the cooling elements (1). The arrangement includes a survey line (5) that is by intermediation of a valve arrangement (6) in fluid connection with at least one cooling element cycle (3), so that the cooling fluid is conducted alternatively through the survey line (5) to the collection header (4) or past the survey line (5) to the collection header (4).

Abstract: Techniques for airflow analysis are provided. In one aspect, a mobile sensing device is provided. The mobile sensing device includes an airflow sensing system having a plurality of airflow sensing units arranged in a grid. Each airflow sensing unit includes a first air passage that contains at least one first airflow sensor; a second air passage perpendicular to the first air passage, wherein the second air passage contains at least one second airflow sensor; and a third air passage perpendicular to the first air passage and the second air passage, wherein the third air passage contains at least one third airflow sensor.

Abstract: The improved monitoring device includes a data acquisition device with an accelerometer inside a bendable tube. One end of the tube is connected to a pole that may be secured to the top of a sewer manhole, while the other end is submerged in a fluid flow. The tilt, oscillations, and pressure exerted upon the tube due to fluid flow are measured and recorded. An improved method includes installing several monitoring devices into sewer system manholes, recording fluid level and flow, reading the recorded data, and displaying the data in chart or map form. Data may be displayed in two or three dimensional maps that may be overlaid with information of topography, street maps, and single or multiple sewer systems. Data displayed on the maps may include fluid flow rates, fluid levels, derivatives and integrals of flow rates, and differences in fluid levels or flow between monitoring devices.

Abstract: A system is provided for measuring flow in a pipeline which, in use, carries a stratified flow of a first liquid and a second, denser liquid. The system comprises: a section of the pipeline in which the stratified flow is uphill; a section of the pipeline in which the stratified flow is downhill; and a holdup meter on each of said pipeline sections for measuring the holdup in each section. The flow rates of the first and second liquids can be calculated from the measured holdups.

Abstract: A water meter has a meter register having an encoder having electromagnetic wave emitters, e.g., infrared emitters to measure water flow and direction of water flow through the meter. The encoder has two of three spaced emitters directing infrared rays at predetermined time intervals toward a rotating detector wheel having a reflective surface portion and a non-reflective surface portion facing the emitters and an infrared sensor. The reflective surface portion of the detecting wheel reflects the infrared rays incident thereon toward the sensor. A microprocessor connected to the sensor acts on signals from the sensor to determine material flow. The meter register transmits the signal to a distant receiver. The microprocessor of a meter register has an algorithm to prevent the meter register from sending signals until after the meter register or a water meter having a meter register is installed and water moved through the meter.

Abstract: An instrument for detecting leaks in a hermetically sealed package. The instrument includes (i) a hollow needle, (ii) a mass flow rate sensor in sealed fluid communication with the lumen defined by the hollow needle, and (iii) a vacuum pump. The vacuum pump is in fluid communication with the lumen defined by the needle for evacuating gas from the hermetically sealed package, and in fluid communication with the mass flow rate sensor for directing mass flow from the evacuated package into operable contact with the mass flow rate sensor so as to permit sensing of any continuing mass flow from the evacuated package. The instrument may further include an oxygen sensor in sealed fluid communication with the lumen defined by the hollow needle for analyzing the oxygen concentration of the gas within the hermetically sealed package.

Abstract: Provided are a flow meter and a flow-rate control system using the same that is capable of measuring a flow rate in a minute flow-rate region with excellent measurement accuracy by preventing or suppressing the generation of bubbles and in which accumulation of the fluid and the bubbles is less likely to occur.

Abstract: An arrangement for measuring air flow includes a source of measurement values and a processing unit. The source of measurement values is operable to generate measurement values representative of a difference in pressure from air obtained on a first side of an obstruction and air obtained on a second side of the obstruction. The processing unit is configured to, in one case, convert any negative measurement values of the measurement values to a less negative value. The processing unit is further configured to perform low pass filtering on the measurement values and convert the filtered measurement values to a flow value.