Showing papers on "Thermal mass flow meter published in 2009"

Mass flow meter and mass flow controller

Abstract: In order to improve a measurement accuracy of a mass flow meter, the mass flow meter comprises a flow rate calculating section that obtains an output signal from a sensor section having a thermosensitive resistive element arranged in a flow channel where a sample gas flows and that calculates a flow rate of the sample gas, a pressure measuring section that measures a primary side pressure in the flow channel, and a flow rate correcting section that corrects the measured flow rate obtained by the flow rate calculating section by the use of the primary side pressure obtained by the pressure measuring section and a gas coefficient determined by an isobaric specific heat of the sample gas.

A MEMS-Based Flow Rate and Flow Direction Sensing Platform with Integrated Temperature Compensation Scheme

Abstract: This study develops a MEMS-based low-cost sensing platform for sensing gas flow rate and flow direction comprising four silicon nitride cantilever beams arranged in a cross-form configuration, a circular hot-wire flow meter suspended on a silicon nitride membrane, and an integrated resistive temperature detector (RTD). In the proposed device, the flow rate is inversely derived from the change in the resistance signal of the flow meter when exposed to the sensed air stream. To compensate for the effects of the ambient temperature on the accuracy of the flow rate measurements, the output signal from the flow meter is compensated using the resistance signal generated by the RTD. As air travels over the surface of the cross-form cantilever structure, the upstream cantilevers are deflected in the downward direction, while the downstream cantilevers are deflected in the upward direction. The deflection of the cantilever beams causes a corresponding change in the resistive signals of the piezoresistors patterned on their upper surfaces. The amount by which each beam deflects depends on both the flow rate and the orientation of the beam relative to the direction of the gas flow. Thus, following an appropriate compensation by the temperature-corrected flow rate, the gas flow direction can be determined through a suitable manipulation of the output signals of the four piezoresistors. The experimental results have confirmed that the resulting variation in the output signals of the integrated sensors can be used to determine not only the ambient temperature and the velocity of the air flow, but also its direction relative to the sensor with an accuracy of ± 7.5° error.

A single chip, double channel thermal flow meter

Abstract: The fabrication and experimental characterization of a thermal flow meter, capable of detecting and measuring two independent gas flows with a single chip, is described. The innovative aspect of the sensor is the use of a plastic adapter, thermally sealed to the chip, to convey the gas flow only to the chip areas where the sensors are located. The packaging approach allowed placing two micrometric differential thermal anemometers, present on 4 × 4 mm2 silicon chips, into distinct flow channels. The reduced spacing between the sensing structures required positioning of the latter on channel bends, introducing sensitivity reduction and response asymmetries with respect to single channel devices presented earlier. These effects are explained using fluid-dynamic simulations.

Multi-sensor mass flow meter along with method for accomplishing same

Abstract: A device for measuring fluid flow rates over a wide range of flow rates The invention is particularly adapted for use in micro-fluidic systems including fluids administration to a body of a patient The device operates by producing characteristics variations in the fluid, or pulses, that are subsequently sensed by more than one detector spaced apart from the point of creation of the mark to derive a flow rate Each pulse comprises a small fluid volume, whose characteristics are different from the mean characteristics of the fluid, such as by composition variations created by electrochemical means, such as by electrolysis of a solvent, electrolysis of a dissolved species, or electrodialysis of a dissolved ionic species, or a thermal variation created by focused electromagnetic radiation The device comprises at least two detectors (also sometimes referred to as sensors) to improve the accuracy of the measurement in varying flow rates, to compensate for errors resulting from the drift of the pulses in the fluid, to compensate for varying or unstable flow rates, and to establish a positive signal for sub-range flow A method of measuring fluid flow rate is proposed where measurements comprising data of one mark from at least two sensor readings plus one other time event are combined to determine the reported flow rate

Vibratory flow meter for determining one or more flow fluid characteristics of a multi-phase flow fluid

Abstract: A vibratory flow meter ( 5 ) for determining one or more flow fluid characteristics of a multi-phase flow fluid includes one or more flow conduits ( 103 A, 103 B). The flow meter assembly ( 10 ) is configured to generate a very low frequency response that is below a predetermined minimum decoupling frequency for the flow fluid and to generate a very high frequency response that is above a predetermined maximum decoupling frequency for the flow fluid, independent of the foreign material size or the foreign material composition. The meter ( 100 ) further includes meter electronics ( 20 ) configured to receive one or more very low frequency vibrational responses and one or more very high frequency vibrational responses and determine the one or more flow fluid characteristics from the one or more very low frequency vibrational responses and the one or more very high frequency vibrational responses.

Low cost capillary flow meter

Abstract: This article introduces a project and some specifications of the capillary flow meter. The functioning of the presented flow meter is based on the measurement of pressure drop caused by the gas flowing through the capillary. The article includes in detail a description of the calibration process of the above-mentioned measuring device and presents its basic specifications and capabilities. The measurement results are barometric and temperature compensated. The upper range boundary of the presented device amounts to 45 μmol/s and the measuring error accounts for 0.3% of the full measuring range of the meter. The costs of material used for constructing the prototype of the capillary flow meter did not exceed US$ 30.

Method of measuring multiphase flow

Abstract: Multi-phase flow is estimated in a flow meter having a first and a second stage by empirically deriving an algorithm for the water and gas fractions, measuring pressures within the flow meter, and estimating a total mass flow rate based on the measured pressures. A corrected total mass flow rate is calculated using a liquid/gas slip correction technique. The oil fraction can be determined from the corrected total mass flow rate and gas and water fractions.

Method for operating a continuous flow steam generator

Abstract: A method for operating a continuous flow steam generator with an evaporator heating surface is provided. A target value for a supply water mass flow is fed to a device for adjusting the supply water mass flow. In order to improve the quality of a predictive supply water or mass flow control and to maintain the enthalpy of the flow medium at the evaporator outlet particularly stable especially when load changes occur, a correction factor is taken into consideration during production of the target value for the supply water mass flow. The correction factor is a characteristic of the temporal derivative of enthalpy or the density of the flow medium at the input of one or more heating surfaces.

Analyses of characteristics of ring-shaped electrostatic meter

Abstract: This article describes the characteristics of ring-shaped electrostatic pulverized fuel meters and their applications. At the University of Teesside, UK, the electrostatic technique has been used to measure pulverized fuel flow concentration, velocity, and mass flow rate under lean-phase condition. The mathematic model has been developed to express the relationship between the root-mean-square (rms) value of the meter's output voltage and solids mass flow rate. The effects of solids velocity and particle size on measurements have also been reflected in the model. Furthermore, the model presents the sensitivity variations over the cross-sectional area of meter and along the pipe axis. The article also introduces the research carried out at Southeast University in China, where the technique has been extended to measure dense-phase flow of pulverized coal, which is common in gasification and blast furnaces.

Upstream volume mass flow verification systems and methods field of the disclosure

Abstract: This disclosure relates to mass flow verification systems for and methods of measuring and verifying the mass flow through a mass flow measurement device such as a mass flow controller. A mass flow verification system comprises a preset volume, a temperature sensor, and a pressure sensor. The measured verified flow determined by the mass flow verification system can be adjusted to compensate for errors resulting from a dead volume within the mass flow measurement device.

Fluidic oscillator flow meter

Abstract: The present invention discloses a feedback type, hydrodynamic oscillator flow meter for measuring the flow of fluids such as gas, air, water and oil, flowing through a conduit. This flow meter gives very accurate measurements over a long period of time since piezoelectric sensors are employed. The working principle of this flow meter is based on the Coanda Effect, which guides the flowing fluid to pass through two feedback paths ( 103, 129 ) alternatively and a linear relationship is obtained between the fluidic oscillation frequency and the flow rate.

Chapter 4 Key Multiphase Flow Metering Techniques

Abstract: Publisher Summary This chapter reviews the measurement techniques, classified into those concerned with density measurement, velocity measurement, momentum flux measurement, mass flux measurement, and elemental analysis. The chapter indicates when the various techniques were first applied to the metering of multiphase flows, how they work, and the ones that have potential for further development. The density of a fluid flowing in a horizontal pipe could be determined directly from the weight of a section of the pipe. Turbine flow meters are frequently used in the measurement of single phase flow rates. The turbine meter operates simply as a hydraulic turbine. It is essentially a device that rotates as the fluid flows through the turbine blades. The rotational speed of the blades is related to the volumetric flow rate. The rate of flow of a single-phase fluid can be determined by measuring the pressure drop across an orifice and employing the Bernoulli equation for frictionless flow. The true mass flow meter (TMFM) is a radial circulation pump. It consists of a rotor with an axial inlet and radial outlet, and a radial stator. The neutron interrogation method determines the content of the respective phases in the channel by measuring the concentrations of specific atom species. After presenting the individual metering techniques, the multiphase flow meters currently available are also discussed in the chapter.

Microwave Mass Flow Meter for Industrial Applications based on a Lefthanded Transmission Line Resonator

Abstract: A particulates mass flow meter has been developed using a composite right/left-handed transmission line resonator. The presented sensor principle promises the possibility to design precise particulate solids mass flow meter with moderate costs. The autocorrelation function is applied to the CRLH-resonator in order to detect the velocity information and the material density from a single measurement. The areas of application of these sensors are gas/solids, gas/liquid and liquid/solids flows in various industrial applications.

Simulation and fabrication of a 2D-flow sensor for thermal characterization of fluids and for flow speed measurements

Abstract: An enhanced flow sensor is under development at IMTEK to enable simultaneous measurement of thermal properties of a fluid and its flow velocity. Simultaneous measurement of these properties is necessary to measure flow rates accurately by thermal means in cases where fluid properties fluctuate in time. Here, we report the design and the fabrication of our flow sensor and present the influence of fluid thermal conductivity on the measurement signals. We further discuss the possibilities of decoupling fluid thermal properties and flow velocity using time-dependent heating. Simulation results suggest that phase shift on a side thermistor location depends more on thermal conductivity than the other thermal properties. Therefore, it can be a key parameter in the measurement of thermal conductivity in the presence of a flow.

Very high frequency vibratory flow meter

Abstract: A very high frequency vibratory flow meter (100) is provided The very high frequency vibratory flow meter (100) includes a flow meter assembly (10) including one or more flow conduits (103A, 103B) The flow meter assembly (10) is configured to generate a very high frequency response that is above a predetermined maximum decoupling frequency for the flow fluid independent of a foreign material size or a foreign material composition The very high frequency vibratory flow meter (100) further includes meter electronics (20) coupled to the flow meter assembly (10) and configured to receive the very high frequency vibrational response and generate one or more flow measurements therefrom

Oil-water two-phase flow measurement using a venturi meter and an oval gear flow meter

Abstract: The performance of a hybrid flow meter for the measurement of oil-water two-phase flow rates is investigated. The hybrid flow meter consists of a venturi meter and an oval gear flow meter. Experimental investigations were undertaken on horizontal pipelines of 15 mm, 25 mm, and 40 mm diameters on an oil-water two-phase flow loop. The total flow rate of the oil-water two-phase flow is in the range of 1.2 ∼ 5.5 m3/h, while the oil volume fraction varies from 0 to 100%. The research verifies that the hybrid flow meter is feasible for oil-water two-phase flow measurement and the accuracy of the hybrid flow meter is satisfactory. Experimental results also indicate that the oil fraction has a significant impact on the selection of the meter coefficient of the venturi and hence the measurement results of density and total mass flow rate.

Thermal type flow meter

Abstract: There is provided a thermal type flow meter capable of accurately detecting a flow rate even when a fluid temperature varies rapidly or when the fluid temperature is high. A probe includes: a first main heating resistor; a second main heating resistor set at a temperature different from that of the first main heating resistor; and a sub-heating resistor for heating lead wires of the two main heating resistors. A CPU of a sensor control circuit finds a fluid temperature by using the two main heating resistors, and finds a fluid flow rate by using at least one of the two main heating resistors.

Modelling and calibration of a Ring-shaped Electrostatic Meter

Abstract: Ring-shaped electrostatic flow meters can provide very useful information on pneumatically transported air-solids mixture. This type of meters are popular in measuring and controlling the pulverized coal flow distribution among conveyors leading to burners in coal-fired power stations, and they have also been used for research purposes, e.g. for the investigation of electrification mechanism of air-solids two-phase flow. In this paper, finite element method (FEM) is employed to analyze the characteristics of ring-shaped electrostatic meters, and a mathematic model has been developed to express the relationship between the meter's voltage output and the motion of charged particles in the sensing volume. The theoretical analysis and the test results using a belt rig demonstrate that the output of the meter depends upon many parameters including the characteristics of conditioning circuitry, the particle velocity vector, the amount and the rate of change of the charge carried by particles, the locations of particles and etc. This paper also introduces a method to optimize the theoretical model via calibration.

Method and apparatus for determining a flow rate error in a vibrating flow meter

Abstract: A method for determining an error in a flow rate of a fluid flowing through a vibrating flow meter is provided. The method includes the step of receiving sensor signals from the vibrating flow meter. A first flow rate is determined using the sensor signals. A fluid density is determined. A fluid velocity is determined using the first flow rate, the fluid density, and a physical property of the flow meter. A flow parameter, V/p is calculated based on the fluid velocity and the density. A flow rate error is then determined based on the calculated flow parameter.

Method for operating a coriolis mass flow rate meter and coriolis mass flow rate meter

Abstract: The invention relates to a method for operating a Coriolis mass flow rate meter (1) and a Coriolis mass flow rate meter with at least one measuring tube (2, 3), through which a medium flows and which is excited so as to perform oscillations, with at least two oscillation pickups (24, 25), which are spaced apart from one another in the longitudinal direction of the measuring tube, for generating in each case one oscillation signal (5, 6) and with an evaluation device (26). In order to detect deposits in the measuring tube, first of all a first indicator variable (II) is used which is based on the damping of the oscillations of the measuring tube. If, on the basis of the first indicator variable, increased damping is established, a second indicator variable (12) is then used, which is based on the manifestation of harmonics in the frequency spectrum of an oscillation signal. This has the advantage that reliable detection of deposits and therefore an indication of the state of meters and pipelines in a process engineering installation are possible.

Microwave mass flow meter for pneumatic conveyed particulate solids

Abstract: A particulates mass flow meter has been developed using a composite right/left-handed transmission line resonator. The presented sensor principle promises the possibility to design precise particulate solids mass flow meter with moderate costs. The Spatial Filter Velocimetry is applied to the sensor in order to detect the velocity information. The simultaneous detection of the velocity and the solids/air concentration from a single measurement, ensure a true mass flow detector. The detector offers good prospects for industrial applications with various scenarios of gas/solids, gas/liquid and liquid/solids flows.

Flow sensor and mass flow controller using the same

Abstract: A low cost, compact, high performance flow sensor that can be made small in size even for use in a large flow rate and a mass flow controller using the same are provided. The flow sensor includes a bypass passage, a sensor passage, and a bridge circuit including heat-generating resistance wires that constitute a part of the bridge circuit and are wound around the sensor passage. The flow sensor determines a total flow rate of a fluid that flows in a branched manner through the bypass passage and the sensor passage at a predetermined flow ratio. The total flow rate is determined by detecting, as an unbalance of the bridge circuit, heat transfer caused by the fluid flowing through the sensor passage and is outputted as a sensor output of the flow sensor. In the flow sensor, the bypass passage includes a plurality of fine flow passages each having a cross-section defined by a substantially linear edge and a curve in contact with the substantially linear edge. The ratio of the equivalent hydraulic diameter (d) of the fine flow passages to the common logarithm of the length (T) of the fine flow passages is 0.27 or less. The flow sensor is installed in the mass flow controller.

Flow rate measurement of oil-water two-phase flow based on V-cone flow meter

Abstract: In petroleum industry, oil-water two-phase flow widely exists in production wells, and the measurement of oil-water flow is significant in oil well logging. One method in common use is to build a theoretic model to connect differential pressures generated by a throttling set with flow-rate. Several measuring models were adopted and compared for model selection and modification. A V-cone with 0.65 diameter ratio was selected as the throttling set because of its special structure and intrinsic advantages. In the experiments, the differential pressures measured under different flow range were processed with a homogeneous flow model. And the results show that the error is small in the condition where the oil and water are well mixed, while the error is big when they are not well mixed. A polynomial of the error and the water percentage was fitted to improve the model accuracy and widen the measurement range.

Recirculation type oscillator flow meter

Abstract: The present invention discloses a recirculation type hydrodynamic oscillator flow meter for measuring the flow of fluids such as gas, air, water and oil, flowing through a conduit This flow meter gives very accurate measurements over a long period of time since piezoelectric sensors are employed The principle of working of this hydrodynamic oscillator flow meter is the generation of a self induced jet where the frequency of oscillations of the fluid jet is proportional to the flow rate