Showing papers on "Thermal mass flow meter published in 1998"

Method and apparatus for detecting and controlling mass flow

Abstract: A process mass flow instrument for measuring the mass flow rate of a process fluid including a fluid inlet, a fluid outlet, a flow passage connecting the fluid inlet and the fluid outlet, a fluid flow sensor which provides a raw output signal corresponding to an unknown mass flow rate and a processor which contains an empirically derived conversion routine for converting the raw output signal to an adjusted signal indicating the mass flow rate of the process fluid. A method for determining an unknown mass flow using an empirically derived conversion function, the function being derived by correlating the output signals of a mass flow instrument sensing the flow of a calibration fluid with the output signals of the mass flow instrument sensing the flow of the process fluid.

Multiphase metering method for multiphase flow

Abstract: The present invention includes a method for multiphase metering of multiphase flow. the method begins with reducing gas volume to about 20% or less, then pumping the flow stream through two meters, a cut meter and a mass flow meter, arranged in series. Computations may be made on the flow stream to determine net oil rate, water cut, and gas fraction in the flow stream.

Micro mass flow control apparatus and method

Abstract: A micro mass flow controller (10) has a sonic choked flow restriction (28) with an oscillatable valve (26) for repetitiously opening and closing the sonic choked flow restriction (28) in a time-modulated sequence to set or vary mass flow rate of gas through the sonic choked flow restriction (28) over a period of time to something between no flow and maximum mass flow rate. A biomorph piezoelectric actuator (40) is coated in a sputtered dielectric layer (78) and then encapsulated in stainless steel or other metal cladding (80). A closure member (46) on the actuator (40) is registered to a valve seat (70) by actuating the actuator (40) to force the closure member (46) in a puddle of adhesive (86) against the valve seat (70) until the adhesive (86) cures.

Multiple-phase flow meter

Abstract: This invention is related to flow meter instrumentation. More particularly, the invention is related to obstruction flow meters which are used in series in a flow conduit to determine the volume flow rate of liquid and gas phases of fluid flowing within the conduit. Multiple flow meters including at least one obstruction type flow meter are positioned serially within a flow conduit such as a pipe. Mathematical equations are developed for each flow meter based upon measured quantities and phase flow rates within the liquid stream. These equations are then solved simultaneously to obtain the desired phase flow rates. Two flow meters are used to determine the gas and liquid flow rates. Alternately three flow meters are used to determine the flow rates of a gas and two liquid phases.

Measuring detector and system for the measurement of gas flow

Abstract: Measuring transducer and system for the measurement of gas flow, especially for the measurement of the pressure and/or flow of a patient's respiratory gas. The surface of the flow channel (1) wall (2) and/or a restricting element (3) in the flow channel which is directly exposed to the gas flow to be measured is provided with a material retaining water inside it.

Flow modulated mass flow sensor

Abstract: A sensor for measuring the flow rate of a fluid through a conduit. The fluid flow rate in the vicinity of a heated temperature sensor is made to cyclically vary from a minimum to a maximum to produce a cyclic signal indicative of the heat removed from the sensor by the fluid flow. The magnitude of the cyclic signal is representative of the mass flow rate of the fluid. A detection circuit responsive to the cyclic signal extrapolates therefrom the mass flow rate and provides an output signal related thereto. Mechanically and electrically balanced configurations enable high speed and high precision measurements to be obtained. Bypass and sampling embodiments are presented. In alternative preferred embodiments circuits are disclosed for determining and maintaining a constant average temperature difference between the sensors and the fluid being sensed, to thereby replace heat loss by the sensors as a result of contact with the fluid being sensed.

A clamp-on ultrasonic cross correlation flow meter for one-phase flow

Abstract: The correlation technique presented offers a good possibility for measuring the average rate of flow of fluids through pipes. The only physical parameter required for the measurement principle is the well known distance between the sensors. The new system presented consists of ultrasonic sensors, transforming the natural, stochastic fluctuations of velocity, pressure and density into two signals with a delay time T, and a real-time correlator, extracting the delay time from the signals and calculating the average rate of flow of the fluid. In contrast to established flow measuring methods, no bluff bodies are necessary and electrical conductivity of the fluid is not required. In contrast to time-of-flight flow meters, a small amount of air bubbles or particles causes no signal losses and does not interrupt the measurement process. In this paper a detailed theoretical signal model describing the interaction of sound waves in random continuum and turbulent media will be presented. With this model the phase modulation of the ultrasonic waves and systematic errors can be described and some design parameters can be optimized. Measurements have been carried out with 40 and 50 mm pipe diameters for direct fluid contact and clamp-on transducers. The measurement error of the new flow meter has been found to be less than 2% from the reference value for a Reynolds number range 25 000-250 000 and, even down to a Reynolds number of 4000, it has been found to be less than 3%.

Friction flowmeter with improved software

Abstract: A method in a pressure transmitter (144) and a pressure transmitter (144) for determining a mass flow rate of a fluid in a conduit (132) measure a differential pressure between two points (136, 138) in the fluid, where the conduit (132) has a substantially constant cross-sectional area between the two points. In one aspect, the mass flow rate is calculated by multiplying the square-root of the differential pressure by a mass flow constant.

Flow meter system with remote displays for each discharge

Abstract: A system for monitoring the volume rate of flow and total volume of liquid being drawn from a supply by way of a plurality of discharge conduits includes a flow meter transducer for associated individually with each of the discharge conduits with the transducers providing pulse information to associated flow meter circuits that are connected in series relationship with one another and to a master control module. Each of the individual flow meter circuits includes a pair of microprocessors, one for determining from the pulse information of its associated transducer the volume rate of flow of liquid out its associated discharge conduit. The second microprocessor is programmed to combine the flow information from its own transducer with combined flow information from an adjacent upstream flow meter circuit in the series string and produces a combined flow output signal for delivery to an adjacent downstream flow meter circuit. In this fashion, flow information associated with each of the discharge conduits can be individually displayed with the total volume rate of flow information being presented on a visual display associated with the master controller.

A remote measuring flow meter for petroleum and other industrial applications

Abstract: The blown venturi flow meter based on a Coanda switched venturi resistance, has been investigated for use in petroleum and other industrial applications. It produces self-induced oscillations in the fluid at a frequency proportional to the rate of flow and the pressure waves are transmitted via the flowing fluid and detected downstream. Experimental work has been conducted by measuring the attenuation of the waves in air flow along a 28.5 m long, 0.05 m diameter pipe downstream of the flow meter, ensuring that the remote flow metering concept is realized. Predictions of pressure pulse strength, pressure loss and frequency for the flow meter in an oil production string have been made. Potential applications of this meter to nuclear fuel reprocessing and other hostile environments have also been demonstrated. Furthermore, accuracy and limitations of the flow meter for engineering applications are considered.

Precalibrated flow meter

Abstract: Precalibrated flow meters which include electronic modules that contain, in a storage memory thereof, a plurality of calibration factors that correspond to a plurality of different fluids. The calibration factors can be chosen during field operations using a touch pad on the face of the meters. The precalibrated flow meters monitor current and accumulative totals of fluid volumes. The precalibrated flow meters can be used in conjunction with air flow compensators which sense the flow of air through a fluid flow passage.

Coriolis flow meter with adjustable excitation phase

Abstract: In a coriolis flow meter, two drivers are provided and a measure of mass flow rate derived from the adjustment of the input signals to each driver required to achieve a desired phase shift in the output. This may give higher accuracy compared to conventional meters in which the phase shift is simply measured, and may also enable determination of other characteristics of the fluid.

Method of measuring flow rates of respective fluids constituting multiphase fluid and flow meter for multiphase flow utilizing same

Abstract: A flow meter for a multiphase flow which comprises a cross-correlation flow meter ( 26 ) for measuring basic values to calculate component ratios of respective fluids constituting a multiphase fluid ( 2 ) comprising a gas and a plurality of liquids in a pipe ( 1 ) through which the multiphase fluid flows; and an arithmetic circuit ( 22 ) for calculating flow rates of the respective fluids, which acquires information concerning ratios of liquid phase components of the multiphase fluid ( 2 ) on the basis of both measured values obtained by the cross-correlation flow meter ( 26 ) at an instance when the pipe ( 1 ) is filled with liquid alone during the passage of the multiphase fluid ( 2 ) through the pipe ( 1 ) provided with the cross-correlation flow meter ( 26 ) and characteristic values of the respective fluids of the multiphase fluid ( 2 ), acquires information concerning ratios of the respective fluids from a time average of the measurements obtained by the cross-correlation flow meter ( 26 ) and the respective characteristic values, then obtains the component ratios of the respective fluids by utilizing the fact that a sum of the component ratios of the respective fluids becomes ( 1 ), calculates an average flow velocity of the multiphase fluid ( 2 ) from time between fluctuations of the measured values obtained by the cross-correlation flow meter ( 26 ), and calculates flow rates of the respective fluids by utilizing the respective component ratios and the average flow velocity.

Design of a new sensor for mass flow controller using thin-film technology based on an analytical thermal model

Abstract: Thermal mass flow controllers are widely used in the semiconductor industry to deliver accurate process gas compositions and concentrations to the processing chamber. The sensor, a stainless-steel capillary tube, is the most critical part of the mass flow controller. We have designed a new sensor using thin-film technology in order to improve its reliability and to decrease its response time. The two temperature sensors are deposited platinum on an electrical insulating layer directly upon the capillary tube (without exposure to the gas stream) whereas the sensor is constantly heated by a resistive wire. The so-obtained sensors are very promising and the new design and technology could give us improvements which the old design and technology (two resistive coils) would not have been able to give us. The physical mechanisms of this new sensor are described by a third-order steady-state analytical thermal model which gives good results when compared with experiments. This fundamental study also includes the evolution of the correction factors as a function of the flow. We present here the thermal model, the new structure of the sensor, and its advantages.

Measuring element, mass air flow meter therewith and compensating method for accurately measuring air flow

Abstract: An improved measuring element for a mass air flow meter is provided with a temperature sensor for detecting a typical temperature indicative of the impact of heat on a heating resistor. The element is formed on a heat transfer pass from a configuration member supporting a substrate on which the heating resistor for measuring an air flow rate is formed, and an air temperature sensor for detecting air temperature, formed on the substrate and out of the air flow impinging the heating resistor.

Coriolis mass flow meter with two drivers

Abstract: In a coriolis flow meter, two drivers are provided and a measure of mass flow rate derived from the adjustment of the input signals to each driver required to achieve a desired phase shift in the output. This may give higher accuracy compared to conventional meters in which the phase shift is simply measured, and may also enable determination of other characteristics of the fluid.

Induction heated mass flow sensor

Abstract: Sensors for measuring the flow rate of a fluid and for monitoring heat transfer. An induction-heated temperature-responsive sensor in contact with and cooled by the fluid, changes temperature in proportion to the quantity of heat removed by the fluid thereby providing a basis for determining flow rate or heat transfer. A flow modulation method and apparatus for improving the precision of flow rate measurement is also presented.

Rotary meter having flow conditioning chambers for pressure pulse reduction

Abstract: An improved rotary fluid meter is provided having expansion chambers for conditioning pressure pulses that may occur in the flow of fluids. The pressure pulses, which inhibit the meter's ability to accurately measure, may originate from within a metering device or from without it. The pressure pulses may be generated upstream of the meter. Fluid flows into the meter through a fluid flow conduit. At least one flow conditioning chamber which is of such a volume and a shape as to enable it to substantially dampen pressure pulses so as to improve the accuracy of the rotary meter is provided along the fluid flow conduit.

Automatic flow/flow ratio conversion data calibrating device and gas supplying device

Abstract: PROBLEM TO BE SOLVED: To make automatically calibratable the flow/flow ratio conversion data. SOLUTION: At the time of calibrating the flow/flow ratio conversion data of H 2 gas, a fluid flow controller 55 designates a prescribed target value in a mass flow controller 49. Also, the fluid flow controller 55, O 2 gas source 42, and a mass flow controller 50 supply O 2 gas in fluid flow corresponding to the target value of the mass flow controller 49 designated by the fluid flow controller 55 or less to the mass flow controller 49. Then, the fluid flow controller 55 calibrates the flow/flow ratio conversion data of H 2 gas based on the flow of O 2 gas supplied to the mass controller 49 and the detected value of the mass flow controller 49 at the time of supplying the gas in the flow to the mass flow controller 49. Then, the flow/flow ratio conversion data of O 2 gas is calibrated in the same way. COPYRIGHT: (C)1999,JPO

Interface apparatus for adapting a gas flow valve to a gas meter

Abstract: A gas flow valve is adapted to mimic an existing plumbing arrangement between the gas flow meter 10 and inlet and outlet plumbing at a point of use. By providing a similar arrangement of mating parts and union nuts, the gas flow valve 20 can be easily and quickly installed between the inlet and outlet plumbing and the gas flow meter without having to replumb the plumbing. The gas flow valve 20 can either directly connect between both the inlet and outlet plumbing and the gas flow meter, or could connect between either the inlet or the outlet plumbing and the gas flow meter 10, with the other connection being provided either by the original connection between the gas flow meter and the plumbing or by an additional inserted pipe.

Volumetric flow metering apparatus

Abstract: A volumetric flow meter that includes a defined volume and sensors that detect when liquid begins to fill the defined volume and when that volume is full. A circuit or equivalent logic is preferably provided to generate a signal representative of flow rate based on the size of the defined volume and time required to fill that volume. The flow meter is constructed of economical and durable components. A method of flow metering is also disclosed.

Method of testing and calibrating a mass flow meter e.g. in flow-line of IC-engine

Abstract: The method involves connecting a mass flow meter to be tested flow-wise in series with a reference mass flow meter, and varying the gas flow in the flow channel through both mass flow meters with regard to the mass flow. The gas stream through a final control element is varied, so that the mass flow in the flow channel changes from an initial value continuously to a final value, without regulation of the mass flow to fixed mass flow values in the flow channel. At the same time, the measured values of the mass flow meter being checked, together with the reference values of the reference mass flow meter, are ascertained.

Microprocessor based flow rate and flow volume indicator common for any flow sensor which gives pulse output

Abstract: Design of an Intel 8085 Microprocessor based flow rate and now volume indicator common for both Turbine flowmeters and vortex shedding flow meters are given. The above indicator can be used not only for the above two types of now meters but also for any other flowmeter which gives pulse output. The flowmeter can be used in any medium (liquid or gas). The only required information for the design are the Maximum Flow Rate and the mean "Meter Factor" of the flow meters; the design is applicable for flowmeters of any size/diameter. The mean "Meter Factor" should be present at site using 4 thumb wheel switches before the operation of the meter. The maximum flowrate and mean "meter factor" values of the flowmeter are used to decide the setting of the 5th Thumb wheel switch which in turn decides one of the four set durations for which the pulses from the flow sensor are to be counted periodically for calculation of flow rate information. The microprocessor reads the settings of the 5 Thumb wheel switches and pulse counter contents and calculates the flow rate and flow volume and displays them in digital form. The paper gives the block diagram and the flow chart for the operation of the indicator.

Method for measuring density and mass flux

Abstract: The invention concerns a method for measuring density and mass flux in dispersed systems with a gas as a liquid phase. To this end, sound velocity in the system is measured both in the direction of flow and against the direction of flow.

Fluid flow measurement

Abstract: Apparatus and method for determining an estimate of flow stability in addition to a measure of flow velocity distribution, by monitoring changes over time of flow measurements from a plurality of spaced apart measurement points.

Mass flow measuring device and method therefor

Abstract: PROBLEM TO BE SOLVED: To provide a device for measuring and controlling accurately the mass flow of a process gas without calibrating it with the process gas, by finding experimentally an output signal of the mass flow measuring device for calibration by relating it to an output signal of the mass flow measuring device for measuring the mass flow of the process gas. SOLUTION: A mass flow measuring device for process comprises a fluid inlet 13, a fluid outlet 14, a passage for connecting the fluid inlet 13 with the fluid outlet 14, a fluid flow sensor for outputting a raw output signal corresponding to an unknown mass flow, and a processor. The processor includes a conversion routine for converting the output signal into an adjusted output signal showing the mass flow of process fluid. The conversion routine is found experimentally by using a mass flow measuring device 26 for calibration similar to the mass flow measuring device for process. An output signal of the device 26 measuring a mass flow of calibration fluid different from the process fluid is related to the output signal of the device for measuring the mass flow of the process fluid.