Showing papers on "Thermal mass flow meter published in 1992"

Control apparatus and method for controlling fluid flows and pressures

Abstract: Control apparatus and method for controlling the flow of fluid across a valve includes a differential pressure measurement across the valve and a flow meter for measuring the flow, and the information from the differential pressure and from the flow meter is compared to predetermined parameters, and in response to the comparison, the valve is modulated to provide the desired flow.

Coriolis effect mass flow meter

Abstract: A Coriolis effect mass flow meter for measuring mass material flow in a conduit. The provided meter may be clamped directly onto an existing pipe or other conduit without diversion of the flow. The meter provides a driver (20), such as a magnetostrictive driver, to oscillate a section of pipe between two supports (12, 14). The driver (20) is mounted at or near an anti-node of the second harmonic mode of the natural frequency of the pipe section. A sensor (30) mounted adjacent the driver operates through a control circuit (Fig. 5) to control the frequency of oscillation of the pipe section. A second sensor (32), such as an accelerometer, is mounted at the node point of the second harmonic mode of the natural frequency of the pipe section during zero flow, (zero flow node point). The second sensor measures the amplitude of displacement of the zero flow node point due to the Coriolis effect forces from the mass of the material flowing through the oscillating pipe. This measurement is indicative of the mass flow rate of the material flowing through the pipe. The meter is not dependent upon phase shift detection and is not susceptible to extraneous noise and does not require a complicated mounting. In alternative embodiments, the meter is prefabricated on a section of pipe which can then be installed in a pipeline as an off the shelf item.

Thermal mass flow sensor

Abstract: A vertical flow thermal mass flow sensor for a vertical flow thermal mass flow meter of a vertical flow thermal mass flow controller has a sensor tube having a gas inlet for receiving a gas to be metered. The sensor tube includes a first curved convection trap and a second curved convection trap for preventing convective flow of the gas through the sensor tube. A thermally responsive winding is wound about the sensor tube and is energized from a source of electrical energy. The resistance of the thermally responsive winding is responsive to the rate of flow of the gas through the sensor tube and provides an indication thereof.

Gas supply apparatus

Abstract: According to this invention, a gas supply apparatus includes a bomb, a mass flow controller, a valve, and a heating means. The bomb is filled with a liquid gas. The mass flow controller controls a flow rate of an evaporated gas supplied from the bomb to supply the liquid gas having a vapor pressure lower than an atmospheric pressure to a vacuum vessel evacuated at a predetermined degree of vacuum through a long pipe. A valve is arranged between the bomb and the mass flow controller and performs supply/interruption of the gas flowing into the mass flow controller. A heater heats the mass flow controller, the valve, and a pipe for connecting the mass flow controller and the valve.

Flow sensor system and method

Abstract: A gas flow sensor system, using hot wire flow and temperature sensors, compensates and corrects for various factors, such as water vapor content and gas composition in the measured gas, gas temperature, physical differences in the sensors, ambient atmospheric pressure, and nonlinearities in the system Physical differences in the sensors are corrected by adjusting the magnitude of the constant current flowing to the temperature sensor Water vapor content and gas temperature corrections are made by modifying a flow temperature signal based on the resistance of the temperature sensor to form a flow reference signal indicative of a desired resistance difference between the resistances of the temperature and flow sensors, which resistance difference varies with the flow temperature signal The flow reference signal is compared to a flow resistance signal (indicative of the resistance of the flow sensor) and the resulting flow correction signal is used to control the current flow to the flow sensor A flow output signal based on the current flow to the flow sensor provides an indication of flow rate This flow output signal can then be corrected for the composition of the gas being measured This composition corrected output can then be further corrected for nonlinearities in the system by use of a look-up table This further corrected output signal can then be still further corrected for such factors as ambient pressure and standard temperature

Improved coriolis mass flow rate meter

Abstract: A flow meter apparatus for measuring the mass flow rate of a fluid using the Coriolis principle. A single straight flow conduit (1) is employed which is vibrated in a radial-mode of vibration. Coriolis forces are thereby produced along the walls of the flow conduit (1) which deform the conduit's cross-sectional shape as a function of mass flow rate. Additional embodiments are disclosed employing radial vibration of selected portions (21) of the flow conduit (1) walls. In addtion, a method is described to determine the pressure and the density of a fluid by simultaneously vibrating a flow conduit (1) in two modes of vibration and thereby determining pressure and density based on changes in each frequency.

Mass flow sensor for very low fluid flows

Abstract: A fluid flow sensing apparatus for measuring very low fluid flows comprising a fluid mass flow sensor for measuring the mass flow rate of a fluid from a temperature differential between predefined points within the sensor; a fluid flow channeling element for accepting the fluid at an input temperature and pressure and directing the fluid across the sensor, and wherein the input temperature and pressure about the sensor is maintained; and a fluid flow dampening element for providing an average fluid flow to the sensor.

Portable wastewater flow meter

Abstract: A portable wastewater flow meter particularly adapted for temporary use at a single location in measuring the rate of liquid flow in a circular entrance conduit of a sewer manhole both under free flow and submerged, open channel conditions and under fill pipe, surcharged conditions, comprising an apparatus having a cylindrical external surface and an inner surface that constricts the flow through the apparatus in such a manner that a relationship exists between (1) the difference between the static pressure head of liquid flowing through the entrance of the apparatus and the static pressure head of liquid flowing through the constriction, and (2) the rate of liquid flow through the apparatus.

Non-intrusive liquid flow meter for liquid component of two phase flow based on solid or fluid borne sound

Abstract: A method for measuring the liquid mass flow rate exiting a two phase (gas/liquid) feed nozzle includes determining the Power Spectral Density from the output of a vibrational sensor (accelerometer or dynamic pressure sensor) in close proximity to the nozzle or in contact with the fluid within the nozzle in a frequency band that includes resonant peaks whose magnitude or area is strongly dependent on the mass flow rate of the liquid and which increases as the flow increases. Measurement of the area of the resonant peaks or of a band of frequencies that includes them can be correlated with the liquid flow and is insensitive to the gas flow.

Electromagnetic flow meter with weir

Abstract: A weir is placed across a pipe section and an electromagnetic flow meter with multiple electrodes is located upstream of the weir. The liquid level and velocity of fluid in the pipe section are evaluated by the electromagnetic flow meter to determine flow rate.

Air flow rate meter

Abstract: A flow rate meter for determining the mass or flow rate of flowing air, having a temperature-dependent measuring resistor disposed in an air bypass conduit. The air bypass conduit has a convergent portion in the region of the measuring resistor in which the air flow is accelerated. As a result of the air flow the effects of any air disturbances upon the measuring element are reduced. The following geometric relationships are advantageous: l 1 /l s >3.8, l 1/2 >1.5, l 1 /1 3 >2.0, l 1/4 >9.0, l 5 /l s >1.5, l 5 /l 6 =1.7 to 1.9, b 1 /b s >40.0, b 1 /b 2 >2.0, l 1 /b 1 >3.5, and l 5 /b 3 =5.5 to 6. The air flow rate meter is especially suitable for determining the mass or flow rate of aspirated air in mixture-compressing engines with externally supplied ignition as well as air-compressing, self-igniting engines.

Coriolis-mass flow meter

Abstract: Shown and described is a mass flow meter for flowing media which operates according to the Coriolis principle, with a line inlet (1) leading to at least one the flowing medium Coriolis line (2), with a line outlet (3), with at least one of the Coriolis line acting, vibration generator, not shown, detected with at least one Coriolis forces and / or based on Coriolis forces Coriolis oscillations, Schwingungsmeswertaufnehmer not shown, and with a measuring device housing (5). According to the invention, a mass flow meter has been created, the "vibration-autonomous" is largely, namely the fact that a support system (4) with a carrying system's natural frequency that is substantially greater than the line resonant frequency and the Coriolis natural frequency, it is provided that the is the Coriolis line (2) to the support system (4) is connected, that the line inlet (1) and the line outlet (3) to the support system (4) are connected and that the measuring device resonant frequency is substantially smaller than the support system resonant frequency.

Mass flow controller flow rate verification system

Abstract: PURPOSE: To provide a mass flow controller rate examination system which can examine the flow rate measuring precision of mass flow controllers in a state where they are incorporated in piping as they are. CONSTITUTION: When cutoff valves 3A-3E are closed, and cutoff valves 9, 4A-4E and 2A-2E are opened, process gas is scavenged from within piping and the piping is filled with nitrogen gas with prescribed pressure. Then, the valve 9 is closed and nitrogen gas in the piping is discharged through the mass flow controllers 1A-1E. This when the indication value of a pressure gage 10 becomes a prescribed value is measured, and the real flow rates of the mass controllers 1A-1E are obtained. Thus, the abnormality of the mass controllers 1A-1E can be detected. COPYRIGHT: (C)1994,JPO&Japio

Operating experience using venturi flow meters at liquid helium temperature

Abstract: Experiences using commercial venturi to measure single phase helium flow near 4 K (degree Kelvin) for cooling superconducting magnets have been presented. The mass flow rate was calculated from the differential pressure and the helium density evaluated from measured pressure and temperature. The venturi flow meter, with a full range of 290 g/s (0.29 Kg/s) at design conditions, has been found to be reliable and accurate. The flow measurements have been used, with great success, for evaluating the performance of a cold centrifugal compressor, the thermal acoustic heat load of a cryogenic system and the cooling of a superconducting magnet after quench.

Method for determining the flow of exhaust gases

Abstract: To analyse the exhaust gas of motor vehicle engines, the flow rate of the exhaust gas is measured by means of flow meters in accordance with the principle of the Karman vortex street. Ambient air is mixed into the exhaust gas via a basic airline (7) with a flow meter (9) at a flow rate which is approximately equal to the lower limit of the measuring range of a flow meter (13) arranged in a first mixed gas line (12) carrying the exhaust gas and the basic air. An analysing device (3) and a computer (5) are furthermore provided. For particle determination in the case of diesel engines, a dilution tunnel (20) can be built into a second mixed gas line (25) with a flow meter (21). The invention is used for analysing the exhaust gases of motor vehicle engines.

Development and evaluation of a meter for measuring return line fluid flow rates during drilling

Abstract: The most costly problem routinely encountered in geothermal drilling is lost circulation, which occurs when drilling fluid is lost to the formation rather than circulating back to the surface. The successful and economical treatment of lost circulation requires the accurate measurement of drilling fluid flow rate both into and out of the well. This report documents the development of a meter for measuring drilling fluid outflow rates in the return line of a drilling rig. The meter employs a rolling counterbalanced float that rides on the surface of the fluid in the return line. The angle of the float pivot arm is sensed with a pendulum potentiometer, and the height of the float is calculated from this measurement. The float height is closely related to the fluid height and, therefore, the flow rate in the line. The prototype rolling float meter was extensively tested under laboratory conditions in the Wellbore Hydraulics Flow Facility; results from these tests were used in the design of the field prototype rolling float meter. The field prototype meter was tested under actual drilling conditions in August and September 1991 at the Long Valley Exploratory Well near Mammoth Lakes, Ca. In addition, the performance of severalmore » other commercially available inflow and outflow meters was evaluated in the field. The tested inflow meters included conventional pump stroke counters, rotary pump speed counters, magnetic flowmeters, and an ultrasonic Doppler flowmeter. On the return flow line, a standard paddlemeter, an acoustic level meter, and the prototype rolling float meter were evaluated for measuring drilling fluid outflow rates.« less

High accuracy fuel flowmeter. Phase 2C and 3: The mass flowrate calibration of high accuracy fuel flowmeters

Abstract: A facility for the precise calibration of mass fuel flowmeters and turbine flowmeters located at AMETEK Aerospace Products Inc., Wilmington, Massachusetts is described. This facility is referred to as the Test and Calibration System (TACS). It is believed to be the most accurate test facility available for the calibration of jet engine fuel density measurement. The product of the volumetric flow rate measurement and the density measurement, results in a true mass flow rate determination. A dual-turbine flowmeter was designed during this program. The dual-turbine flowmeter was calibrated on the TACS to show the characteristics of this type of flowmeter. An angular momentum flowmeter was also calibrated on the TACS to demonstrate the accuracy of a true mass flowmeter having a 'state-of-the-art' design accuracy.

Method for measuring local flow speed of a fluid flow in a channel.

Abstract: The invention relates to a method for measuring local flow speed of a fluid flow in a channel (1), the temperature of the fluid being measured in the channel at two points located one behind another in the flow direction (4) with the aid of a thermocouple (2, 3) in each case. According to the invention, the measurement signals of the two thermoelements are correlated and the flow speed is derived therefrom.

Positive-displacement fluid flow-measuring system

Abstract: A positive-displacement fluid flow measuring system, especially for hydrocarbon fuel dispensers. The measuring system comprises, in addition to a positive-displacement meter per se, a correction system for correcting the loss of head in the meter. The correction system comprises a differential pressure detector responsive to the difference between the pressures at the inlet and the outlet of the meter. The displacement of the membrane enables an external motor to be coupled to the shaft of the meter by means of the plates.

Non-intrusive flow meter for the liquid component of two phase flow based on solid, liquid or gas borne sound

Abstract: . The method includes determining the Power Spectral Density from the output of an accelerometer in close proximity to the restric- tion orifice controlling the gas flow, or determining the Power Spectral Density from the output of a pressure transducer in contact with the gas flow on the down stream side of the restriction orifice. The liquid flow can then be obtained from a predetermined correlation between the RMS Vibrational Signal and the mass or liquid flow rate.

Device for measuring the mass flow rate following the coriolis principle

Abstract: In order to increase the measurement accuracy when determining the mass flow rate of a conveyor material, in particular a multiphase flow composed of a bulk material and a gas, using the Coriolis principle, it is proposed to measure the mass flow rate (M3) of the conveyor fluid, in particular conveyor air, before entry into the Coriolis measurement wheel (4), and then to form the difference (M2) between the total mass flow rate (M1), determined at the measurement wheel (4) by the drive torque, of the conveyor material together with the conveyor fluid and the separately established mass flow rate (M3) of the conveyor fluid. In a preferred embodiment, the conveyor fluid measuring device is also constructed as a Coriolis measurement wheel. The proposed method and the corresponding device enable account to be taken of the conveyor fluid mass flow rate when determining the mass flow rate of the conveyor material. … …

A Slot Flow Meter for Large Bulk Solids Flows

Abstract: A slot flow meter to measure the flow rate of particulate solids consists of a chamber with one or more vertical slots in its sides, attached to a weighing device such as a load cell for continuously weighing the chamber contents. Solids enter the chamber from the top, and flow out through the slot or slots. Flow rate is proportional to solids height in the slot, but as height measurement presents practical difficulties an alternative approach has been followed. The weight of solids, which is easily measured, is proportional to height; and solids flow rate can be correlated with the output of the weighing device. A prototype meter capable of measuring flow rates up to 7.2 kg s-1 (26 tonnes per hour) has been installed in a urea plant in the North Island of New Zealand. The general design, the calibration methods used and the operating characteristics of the meter are discussed, and an outline of the theory governing the behaviour of the meter is presented.

Volumetric system to measure the flow rate of a fluid

Abstract: The invention relates to a volumetric system to measure the flow rate of a fluid, in particular for hydrocarbon distributors. The measuring system comprises, in addition to the volumetric meter (14) proper, a system (18) to correct load losses of the meter. The correcting system comprises a differential pressure sensor (38) subjected to the difference between the pressures at the intake (32) and the outlet (34) of the meter. The displacement of the diaphragm (40, 42) allows the coupling via the plates (56, 61) of an external motor (36) to the shaft (24) of the meter.