Showing papers on "Thermal mass flow meter published in 1997"

Thermal mass flowmeter and mass flow controller, flowmetering system and method

Abstract: A flowmeter (100) or mass flow controller (101) used in a manufacturing process with toxic and reactive process fluids. A fluid flow sensor (114) sensesfluid flow. A set point is established based upon predetermined temperature and pressure conditions at which the fluid will be utilized in the process. A valve drive (124) operates a fluid flow valve (126) to the resulting fluid flow rate, this being based upon the sensed flow rate and the set point. A control unit (122) controls the valve drive. The control unit accesses a calibration data set to determine the amount of fluid to be delivered by the fluid flow valve based uponthe sensed flow rate and the set point. This calibration data set is created for the controller over its operational range using a calibration fluid having similar thermodynamic transport properties to a process fluid. The instrument is calibrated using the calibration fluid and the data set is produced by converting the calibration data using process fluid data stored in a data base (200). Accessing the data set stored in the instrument together with routing signals over a communication network (300) permits the instrument to precisely control process fluids without having to introduce external correction factors or other adjustments to the process.

Coriolis viscometer using parallel connected coriolis mass flowmeters

Abstract: A pair of flowmeters having unequal flow carrying capabilities are effectively connected in parallel to receive a material flow The material flow through the flowmeters supplies output signals to associated meter electronics which derives mass flow and other information for each meter The meter electronics is pre-programmed with information regarding the physical characteristics of each flowmeter The meter electronics uses the pre-programmed information and the derived material flow velocity for each meter and other information to determine the viscosity for the material in the flowmeters

Mass flow measuring device

Abstract: A mass flowmeter includes a hollow flow tube with a contoured longitudinal bore. Inserted into the contoured longitudinal bore are preferably four rods. The rods establish stable axial vortices within the hollow flow tube. Pressure pulses on the flow rods produced by the vortical flows are measured by pressure transducers and associated electronics then translated into an accurate measurement of mass flow. Total wide ranging flow stability and high signal output characterize this mass flowmeter as well as its ability to handle liquids, gases, and fluidized solids.

Method and apparatus for monitoring liquid flow through an enclosed stream

Abstract: A liquid flow meter is designed to monitor the flow of a liquid through an enclosed stream such as through the tubes or internal passageways of a device such as a filtration system. The liquid flow meter includes an axial-flow magnetic turbine and a detector such as a reed switch that monitors turbine rotation by counting pulses. The counted pulses are then used to determine the aggregate volume of liquid that has flowed through the flow meter. When the liquid flow meter is used in a domestic potable water filtration system or in a similar application, the counted pulses can also be used in conjunction with a timer to determine liquid flow rate as well as the remaining useful life of a filter cartridge of the filtration system and/or of the remaining volumetric filtration capacity of the filter cartridge. The liquid flow meter exhibits high linearity or consistency of flow measurement over a wide range of liquid flow rates--even at very low pressures and low flow rates. The liquid flow meter also exhibits a very small pressure drop thereacross, requires minimal electrical power for operation, and is also compact and versatile so as to be usable with minimal modification to existing filter assembly designs.

Velocity and mass flow rate profiles of dry powders in a gravity drop conveyor using an electrodynamic tomography system

Abstract: This paper describes measurements made on a gravity drop conveyor using two arrays of axially spaced electrodynamic sensors to measure axial velocities close to the wall of the conveyor and velocity profiles both of flowing sand and of plastic beads. The level of correlation obtained using pixels is investigated. The velocity profile is combined with a tomographic concentration profile to estimate the mass flow profile, which is summed over the measurement cross section to estimate the mass flow rate. A calibration of the tomographically determined mass flow rate versus the actual mass flow rate is presented.

Tangential rotor flow rate meter

Abstract: A flow meter is provided that can be used to measure the flow of fluids from a fluid source to a receiving system, and methods of using the flow meter to measure fluid flow. The flow meter is composed of a housing that contains a fluid flow sensing member in the form of a rotatable bladed rotor or turbine in one chamber and a sensor and a signal-conditioning circuit in a second separate chamber. The rotor rotates by fluid flow through the housing chamber. The rotor preferably contains a magnet that passes over a magnetically-operated sensor and triggers it to produce a signal that is processed by the conditioning circuit into a 4-20 mA output signal that indicates a range from no flow to full flow of the liquid through the flow meter.

A net mass liquid filler

Abstract: Liquid filling apparatus and method of producing a fill or dose of a defined quantity of liquid based upon the mass of the liquid. In one embodiment, a servo motor driven rotary positive displacement pump is used to produce flow through a Coriolis mass flow meter to feed a positive shut-off filling nozzle, wherein mass flow data from the meter is used to control the servo motor- pump-nozzle to produce a precise fill dose of liquid based upon its mass.

Apparatus to check calibration of mass flow controllers

Abstract: A calibration apparatus is applied to a gas control panel (46) that uses mass flow controllers (70,98,118) to control the flows of different gases to a processing chamber (42). The gas control panel (46) includes a mass flow meter (150) mounted on the gas control panel (46). The mass flow meter (150) is connected between pre-existing and unused gas valves (152, 156) on the gas control panel (46) in place of a mass flow controller that is also otherwise unused. The meter input valve (152) for the mass flow meter (150) is in fluid communication with the mass flow controllers (70, 98, 118). The input and output meter valves (152, 156) are connected to respective pre-existing solenoids (154, 158) which in turn are connected to a gas flow control (48). A final valve solenoid (82) controls a final valve (80) which is also in fluid communication with the mass flow controllers (70, 98, 118) and routes the gases to the processing chamber (42). The calibration system includes a switching device (162) mounted on the gas control panel (46) and connected between the output (163) of the final valve solenoid (82) and a control input (81) of the final valve (82). The switching device (162) has a control input (164) connected to an output of the meter input valve solenoid (154). Thus, in one state, the meter input solenoid (154) inhibits gas flow through the processing chamber (42) and permits gas flow from the mass flow controllers (70, 98, 118), through the mass flow meter (150) in order to check the calibration of the mass flow controllers. In an opposite state, the meter input solenoid (154) inhibits gas flow through the mass flow meter (150) and permits flow to the processing chamber (42).

Mass flow transducer having extended flow rate measurement range

Abstract: A multi-channel mass flow transducer (10) having a single laminar flow element (24) in a primary fluid flow path (14) and multiple secondary flow paths (16) in parallel with and in fluid communication with the primary flow path. An electric circuit (18) is coupled to each of the multiple secondary flow paths for measuring the corresponding flow rate in the primary flow path as a function of temperature of the fluid flowing in the secondary flow paths. A circuit (18) coupled to each of the secondary flow paths includes at least one temperature responsive element (20) in thermal communication with the fluid in the corresponding secondary flow path.

Valve for controlling gas mass flow

Abstract: A fuel admission valve for metering gas without using a mass flow sensor. The valve uses a flow control element and nozzle, an actuator, a fuel supply pressure sensor, a fuel supply temperature sensor, a flow control element position sensor, and a flow control circuit to meter gas in sonic flow with insensitivity to the discharge pressure.

Flow meter that measures solid particulate flow

Abstract: A non-contact solids flow meter for measuring solid particulate flow is comprised of a flow tube, a sensor, and an indicator. The product enters the flow tube at one end and flows downward by gravity past the sensor and then exits the flow tube at the bottom. The sensor is placed in a sensor tube at an angle to the flow of particulate solids. As the product passes the sensor signal (low microwave energy), this energy upon contacting the particulates undergoes a Doppler shift which is detected by the sensor. The width of the sensor beam has to be at least the diameter of the flow tube so that it covers the entire cross-sectional area of the flow tube. In this manner, all particulate materials flowing through the flow tube come in contact with the beam and are thus reflected. The instrument is calibrated and algorithms determined from the calibration to cause the indicator to provide a best fit function over the output range of the indicator.

Gas mass flow control system

Abstract: A gas fuel admission system for use with a gas fuel supply and an internal combustion engine having an engine control unit that produces a desired mass flow signal. The system has a continuously variable gas fuel admission valve having a flow control element and nozzle for metering gas in sonic flow from the gas supply to the engine with insensitivity to the valve discharge pressure. An actuator moves the flow control element relative to the nozzle. The system also has a flow control circuit that responds to the desired mass flow signal from the engine control unit, a gas supply pressure signal from a gas supply pressure sensor, a gas supply temperature signal from a gas supply temperature sensor, and a flow control element position signal from a flow control element position sensor to determine the appropriate flow control element position needed to achieve the desired mass flow at the present engine operating conditions.

Field Test of the In Situ Permeable Ground Water Flow Sensor

Abstract: Two in situ permeable flow sensors, recently developed at Sandia National Laboratories, were field tested at the Brazos River Hydrologic Field Site near College Station, Texas, The flow sensors use a thermal perturbation technique to quantify the magnitude and direction of ground water flow in three dimensions. Two aquifer pumping tests lasting eight and 13 days were used to field test the flow sensors. Components of ground water flow as determined from piezometer gradient measurements were compared with ground water flow components derived from the 3-D flow sensors. The changes in velocity magnitude and direction of ground water flow induced by the pump were evaluated using flow sensor data and piezometric analyses. Flow sensor performance closely matched piezometric analysis results. Ground water flow direction (azimuth), as measured by the flow sensors and derived in the piezometric analysis, predicted the position of the pumping well accurately. Ground water flow velocities measured by the flow sensors compared well to velocities derived in the piezometric analysis. A significant delay in flow sensor response to relatively rapid changes in ground water flow was observed. Preliminary tests indicate that the in situ permeable flow sensor provides accurate and timely information on the velocity magnitude andmore » direction of ground water flow.« less

Pressure compensated thermal flow meter

Abstract: A flow meter having reference and active thermal sensing elements and a pressure transducer configured to be placed in a conduit of flowing fluid. Appropriate computation apparatus is employed to modify the flow velocity reading resulting from normal comparison of the thermal sensors in accordance with pressure differences reflected by the pressure transducer.

A flow meter and a method of operating a flow meter

Abstract: A flow meter and a method of measuring flows, such as flows in liquids or gasses, are described, wherein ultrasonic signals are transmitted in two or more directions in different points - that is, one is detected before the next is transmitted - in time in order to, at a given transducer, remove the adverse effects of signals reflected back to a transducer reaching the transducer at the time it is to receive a signal. In addition, a measuring setup is described wherein varying impedances of the transducers are compensated for and wherein the impedances of the transmitting and the receiving electronics have no effect on the measurement. In this setup, the transmitting electronics and the receiving electronics are directly electrically connected, and the transducers are interconnected to this electrical interconnection.

Mass flow rate meter

Abstract: A meter to measure the mass flow rate of gases passing through a flow tube, with the flow tube being incorporated as part of a flow tube assembly mounted for continuous rotation about a spin axis and simultaneous deflection about a measurement axis. Also incorporated as part of the flow tube assembly are counterbalance masses mounted so as to provide radial forces that oppose Coriolis/gyroscopic forces generated from the flow tube. The flow tube assembly is mounted for deflection about the measurement axis using low friction rotary seals. The deflections of the flow tube assembly about the measurement axis have a linear relation to the mass flow rate of gas passing through the flow tube.

Device for measuring the mass of a flowing medium of air aspirated by an internal combustion engine

Abstract: Known devices for measuring the mass of a flowing medium, or flow rate meters, have a measurement element accommodated in a measurement stub, and a flow rectifier with a grid is provided upstream of the measurement element. For easy production and assembly and accurate alignment of a grid (21) with a flow rectifier (20) of the device (1), the grid (21) has integrally formed-on spring elements (30), which deform elastically when the flow rectifier (20) is installed so that by their spring force, in combination with a detent connection (33, 35) provided on the flow rectifier (20), they durably retain the flow rectifier (20) and the grid (21). The device is intended for measuring the mass of a flowing medium, especially for measuring the flow rate of air aspirated by internal combustion engines.

A two-dimensional flow sensor using integrated silicon spreading-resistance temperature detectors

Abstract: A simple silicon two-dimensional (2D) flow sensor for the measurement of both flow direction and speed is described. By integrating two couples of silicon spreading-resistance temperature (SRT) sensors in two perpendicular directions on the surface of a silicon chip, this sensor can detect flow speed and flow direction φ in a full range of 360°. Experimental results confirm theoretical analysis that the output of the sensor increases with the square root of the flow velocity, and the outputs in the two perpendicular directions are proportional to sin φ and cos φ, respectively. The effects of sensor layout are also discussed. With complete oxide isolation for the SRT sensors, the flow sensor could achieve higher sensitivity by operating above the intrinsic temperature of silicon (∼150 °C), or could be used to detect fluid flow at a temperature as high as 300 °C.

Flow measurement in micromachined orifices

Abstract: The flow conditions in micromachined orifices and gaps are discussed for cross section areas in the range of 0.5 to . Aligned to a small suspension beam, different plates with geometries of and reduce the cross section of the flow channel. The mass flow of water is calculated by an analytical model and by FE simulation. A good agreement with the experimental data is shown. The flow induces a plate deflection and a mechanical stress in the suspension. The mechanical stress is measured via an integrated piezoresistive Wheatstone bridge offering full scale output signals up to . Corresponding to the models, the output signal is proportional to the pressure difference and the square root of the mass flow. A sensitivity of is calculated for air flow rates from 0 to 4000 sccm/min. Different mass flow measurements of air and water are presented and aspects of different viscosity and plate geometries are discussed. Therefore, design scaling rules can be deduced for different applications.

Method of magnetic-inductive flow measurement in sewage systems, especially in partially filled pipes, channels, etc.

Abstract: The method involves using a magnetic-inductive flow meter in which the voltages of a number of electrode pairs are measured, the level detected and the volume flow derived using a semi-empirical algorithm. A level-dependent weighted addition of the voltages applied to the electrodes is performed, to homogenize the sensor working function , so that the resulting sensor working function is approximately constant. An Independent claim is also included for a flow meter for implementing the method.

Flow meter within caustic fluids having non-contaminating body

Abstract: A non-contaminating flow meter having an isolation member. The flow meter includes two pressure sensor transducers (42, 44), located on opposite sides of a restriction (35) in a conduit. Each of the pressure transducers is isolated by an isolation member (38) from exposure to fluids flowing through the conduit. The flow meter may be placed in line within a fluid flow line carrying corrosive materials. The square root of the difference in pressure between the two pressure sensors is calculated to determine the rate of low within the fluid line. The flow meter compensates for changes in temperature within the fluid flow line and activates an alarm if the pressure of flow rate within the fluid flow line exceeds or falls below a threshold level.

A flow meter based on using Coriolis forces

Abstract: The flow meter comprises a tube (4) that vibrates under drive from a generator (7) with the displacements of the tube being measured by two sensors (8 and 9) producing signals that are phase-shifted by the Coriolis force acting on the fluid flowing along the tube (4), in a manner that is indicative of its mass flow rate. The originality of the invention consists in a jacket (5) surrounding the tube (4) and in which a fluid (6) is contained and is kept automatically at the same pressure as the flow. This makes it possible to use tubes (4) that are thin and flexible even with flows that are at high pressure.

On the development of a two-phase flow meter for vertical upward flow in tubes

Abstract: A new method for measuring the volumetric flow rate of each phase for two-phase, air and water, flowing upwardly in a vertical tube is developed. This noble device, a Two Turbine Flow Meter System (TTFMS), is composed of two turbine flow meters, a valve, two thermocouples, and two pressure transducers. For a given twophase flow, the rate of rotation of the turbine flow meter is found to depend only upon the volumetric flow rates of gas and liquid at the point of measurement. A calibration model is developed for the turbine flow meter, which provides a simple, general, and accurate relationship between the output signal of a turbine flow meter and the actual two-phase flow rate. The volumetric flow rate of each of the two phases is determined by this model. TTFMS is a simple, durable, and inexpensive two-phase flow measuring device that does not require physical separation of a phase from the two-phase mixture.

Fluid flow meter for gas or liquid, e.g. water meter in large building

Abstract: The meter detects measurement values using sensors (13,15) and transmits them. The current for the sensors and electronics system is automatically generated by converting flow energy into electrical energy, e.g. using a turbine (1) and generator (2). The electronics system includes a pulse counter (8), a signal processor (9) and a memory (10) for storing measurement values, etc. An electromechanical, magnetic, acoustic or optical sensor may be connected to the turbine. A mechanical meter may be connected to the moving parts, e.g. to the turbine shaft.

Design and modelling for a thermal flow sensor

Abstract: Design and modelling have been made for a new type of integrated flow sensor for implementation in a CMOS compatible technology. The sensor is designed for both gas and fluid flow sensing in applications with transient velocity and temperature profiles. This appear also in microfluidics where there is a pulsating flow when drive is made with micropumps. The sensor is analysed for fluid flow and heat transfer. Modelling and optimisation of the sensor give results for the necessary geometrical parameters and materials of the sensor for maximising the sensibility in applications with a known fluid and in a given domain of fluid velocities and temperatures.

Method for calibrating a differential pressure fluid flow measurement system

Abstract: (57) Abstract: a main flow sensor, in a flow rate measuring system comprising a secondary electronic conversion apparatus for converting an electronic signal output representative of fluid flow rate of fluid high pressure signal and a fluid low pressure signal from the main flow sensor , a method of calibrating the system as an integral unit, and applying over the operating range of flow conditions the system a plurality of known reference fluid flow in main flow sensor for each of said plurality of reference fluid flow a step of detecting an electrical output of the secondary electronic conversion apparatus Te, the correction factor for each of the recorded values ​​of the electronic output having a tendency to linearize the relationship between the electrical output of the fluid flow rate measurement system calibration method comprising the steps of establishing and storing a correction factor to the non-volatile memory in the microprocessor which is part of the secondary electronic conversion apparatus.