Showing papers on "Volumetric flow rate published in 1970"

Method and apparatus for mass emission sampling of motor vehicle exhaust gases

Abstract: An air blower draws a mixture of exhaust gases emitted from an internal combustion engine and ambient air through a through-flow duct having a valve means therein at a minimum volumetric flow rate for the mixture in excess of the maximum volumetric flow rate the engine is capable of emitting while a proportional sample of said total mixture is withdrawn into a sample container at a uniform volumetric rate during a test period, the sample thereafter being analyzed to determine the concentration of pollutants of gas constituents therein and compared with the concentration of such pollutants or gas constituents in the ambient air which is sampled concurrently at the same flow rate from an area adjacent that where the ambient air is drawn into the through-flow conduit, total mass or weight of such pollutants or constituents being calculable from the concentration thereof in said sample and the known total mass or weight of air and gas mixture drawn through the duct. Temperature sensing and transducer means produce a first or error signal which is a function of the temperature of gases flowing through said duct, volumetric flow rate sensing means and associated transducer means produce a second signal which is a function of volumetric gas flow through the duct and electrical circuit means are provided in association therewith to cause said second signal to modify said first signal to produce a control signal which causes operation of a servomotor to adjust the valve means until an actual required volumetric flow rate through the duct is attained for any given temperature thereof to maintain a constant mass or weight flow, said actual volumetric flow rate for said gases increasing with increasing gas temperatures above a standard initial flow rate for a standard temperature condition. Circuitry is provided for a system for maintaining constant the rate of mass flow of a gas through a conduit despite temperature changes. The system generates an error signal linear with the absolute temperature of the gas, generates a second signal which is linear with differential pressure across a fixed orifice in the conduit, and thus with velocity of flow therein, modifies the error signal by the second signal to produce a command signal of appropriate polarity to adjust the velocity of gas flow in an inverse feedback manner by controlling a throttling valve in the conduit.

Ultrasonic acceleration of liquid flow through porous media

Abstract: This investigation included a study of the effects of ultrasonic radiation upon the flow rate of crude oil through sandstone and also the effect on both water and oil flow through a porous stainless steel filter. When ultrasonic energy, having a frequency of 20 kHz, was introduced, there was a substantial increase in the rate of liquid flow through all the porous mediums tested. An increase in temperature of the system during ultrasonic radiation was found to increase the oil-flow rate several times beyond that which could be accounted for by the decrease in the viscosity of the oil. A plausible explanation is conjectured to be the fact that under the influence of ultrasonic radiation, a progressive change in the Poiseuille type of flow occurs in the micro-channels of the media as the temperature increased. An equation stipulating the conditions for this departure from Poiseuille flow by ultrasonics was formulated. It was found that the application of pressure on the insonated system increased the maximum rate of oil flow. However, an increase in ultrasonic power was required to attain this maximum oil-flow rate. The ultrasonic power increase needed was proportionately less than the resultant increase in the oil flow rate.

Fluid flow rate meter

Abstract: A device for producing electrical pulses at a rate corresponding to the volume flow rate of air in a passage, with means to discriminate between directions of flow. A vane member is rotatably mounted in the passage and surrounded by a distensible diaphragm. The vaned turbine member has a transverse aperture through which light impulses travel from a light source to a photocell both mounted externally of the passage.

Proportioning device, especially for water treatment systems

Abstract: A proportioning device for the admixture of an additive fluid into a fluid medium flowing in a pipe or conduit. The flow rate of the fluid medium is measured and the pump which introduces the additive fluid is controlled in response to the measured flow rate. The measuring system includes a body disposed to be moved linearly against the force of a spring by the fluid medium passing thereby. In one embodiment, this body has a surface which varies along its length and the additive fluid pump has a plunger in contact with this surface. As the body is moved by the varying flow rates of the fluid medium, the effective plunging stroke of the pump is controlled. In another embodiment, a magnetic field is used to detect changes in the position of the body.

Density corrected flowmeter

Abstract: A fuel management system capable of indicating the mass fuel flow rate, the total mass of fuel consumed and the hours of flight remaining. The mass fuel flow values are determined by multiplying the volumetric flow rates by the density of the fuel. Temperature correction is provided for determining accurate density values at the location of the volumetric measurement positions. Integration of the mass fuel flow rate provides the total mass fuel consumed.

The effect on conversion of flow rate variations in a heterogeneous catalytic reactor

Abstract: The unsteady state behavior of a tubular heterogeneous catalytic reactor, in which significant adsorption effects occur, has been investigated theoretically and experimentally. Transient responses of conversion to step increases and decreases of flow rate as well as to periodic variations in flow rate are considered. A simplified procedure for anticipating gross effects in cyclic processes is suggested.

Orifice structure having two different flow rates

Abstract: THIS INVENTION RELATES TO A NOVEL FORM OF OF ORFICE STRUCTURE PROVIDING A HIGH RATE OF FLOW IN ONE DIRECTION AND A REDUCED RATE OF FLOW IN THE OPPOSITE DIRECTION UNDER THE SAME CONDITIONS.

Apparatus for balancing fluid distribution systems

Abstract: Apparatus for balancing the flow of a gaseous substance in the branch of a fluid distribution system comprising a set of variable gates to regulate the volume flow input, a screen to establish a pressure differential along the length of the unit and a pressure differential measuring system capable of detecting and measuring the pressure drop in the unit due to the screen as a function of the input flow rate and to allow regulation of the output flow by altering the input flow rate in accordance with prior calibration of the measuring system.

Fluid flow meter

Abstract: A fluid is passed through first and second thermally conductive porous conduit elements spaced apart from one another along the path of fluid flow. A heater and a temperature sensor are mounted on each porous element and operated to maintain the two elements at constant preset differential temperatures. Flow rate of the fluid is indicated by the electrical power supplied to the heater on the second porous element to maintain the preset temperature differential. Temperature controlled metal cylinders surround the porous elements to insulate them from the adverse effects of the ambient temperature. A shaped conduit between the porous elements further minimizes heat loss from the fluid and improves measurement accuracy.

Means for determining flow rate and volume of a flowing fluid mass

Abstract: A system which includes a flow meter producing voltage pulses of a frequency proportional to the flow rate of a flowing mass, and a sensing element responsive to a physical condition of the flowing mass with a circuit which produces a DC voltage signal analogous to that condition. A generator provides linear sawtooth voltage pulses against which a comparator circuit compares the analog voltage from the sensing element and circuit. The voltage resultant of the comparison switches a portion of the voltage pulses from the flow meter to a divider circuit element and a subtractor circuit element of the system for conversion of relatively low order changes in the physical condition to their full range equivalents, and for correction of the flow rate or volume as a function of such changes. The flow rate or volume as thus corrected is registered on a suitable flow rate indicator or volume counter.

Experimental and theoretical investigation of continuous flow column crystallization

Abstract: A theoretical and experimental investigation of the separation achieved in a column crystallizer which utilizes a spiral conveyor was conducted to determine the effect of variables associated with continuous flow operation. A system that exhibits negligible solid solubility was used. Several feed mixtures containing less than 31,000 p.p.m. weight cyclohexane in benzene were employed. The principal variables evaluated in this study in a column of constant length were the feed position, internal crystal rate, and flow rates of terminal streams. A mathematical model is developed which considers axial dispersion and mass transfer between the liquid adhering to the crystals and the bulk liquid. The model satisfactorily explains the effect of the variables associated with continuous flow operation and shows that axial dispersion is more dominant in continuous flow than in total reflux operation. It is shown that multiple pass or cascade operation is necessary to produce material of purity higher than a critical level which is related to the feed composition. This occurs because of impurities in the crystal phase which are likely caused by volumetric inclusions.

Fluid sample analyzing apparatus

Abstract: In a method of analyzing a fluid sample employing an electrochemical sensor that has a selectively permeable membrane disposed in the sample chamber, sample fluid to be analyzed is introduced into the sample chamber at a first flow rate, and flow of the sample fluid across the membrane in the sample chamber is continued at a reduced rate for a length of time greater than that required to fill the sample chamber at the first flow rate.

Vapor Phase Etching of GaAs in the H 2 ‐ H 2 O Flow System

Abstract: The etch reaction has been studied as a function of flow rate, temperature, and surface area. Experimental and calculated equilibrium constants for the reaction have been compared. The formation of is considered. The variation of sample surface texture with gas composition is examined.

Fluid flow measurements inside the reactor vessel of the 50 MWe Dodewaard nuclear power plant by cross-correlation of thermocouple signals

Abstract: The determination of fluid flow velocities with conventional equipment is sometimes impossible owing to extreme environmental conditions or unacceptable disturbance of the flow pattern and increase in flow resistance. Transit time analysis of fluctuations in water temperature, pressure, radioactivity, etc., using suitable detecting elements can then still often be applied. In the downcomer region of the reactor system of the 50 MWe Dodewaard boiling water reactor with natural circulation, 30 pairs of fast response thermocouples are used to detect temperature fluctuations in the turbulent flowing water. After amplification and filtering, the signals of each thermocouple pair are fed into a multipoint polarity coincidence correlator to form the cross correlation function C12 (kΔτ). From this function the mean transit time τ1 of the temperature fluctuations to cover the distance l between the thermocouples is easily found. Then the local velocity follows from the simple relation VH2O = 1/τ1. The applied method has proved very useful in the determination of local fluid velocities in the range 0·15-1·50 m s−1. From these local measurements radial and axial velocity profiles and total recirculation flow can be derived.

Apparatus for measuring fluid flow

Abstract: IN APPARATUS FOR MEASURING THE MASS RATE OF FLOW OF A FLUID IMPARTING AN ANGULAR COMPONENT OF VELOCITY TO THE FLUID AND MEASURING THE FLOW RATE IN ARBITRARY TIME UNITS, THE ANGULAR VELOCITY IS IMPARTED TO THE FLUID BY AN IMPELLER. IN THIS INVENTION THE IMPELLER IS DRIVEN BY A TURBINE WHICH IS DRIVEN BY THE FLUID THE RATE OF FLOW OF WHICH IS TO BE MEASURED. VALVES ARE ALSO PROVIDED SO THAT SOME OF THE FLUID WILL AUTOMATICALLY BYPASS THE TURBINE IF THE RATE OF FLUID FLOW RISES ABOVE A PREDETERMINED VALUE. THIS ARRANGEMENT ENABLES THE TURBINE SPEED TO BE MAINTAINED SUBSTANTIALLY CONSTANT OVER A VERY WIDE RANGE OF RATES OF FLUID FLOW.

Fluidic digital pneumotachometer

Abstract: A device for measuring fluid flow comprises a fluid oscillator including a feedback path whose RC time constant may be varied in response to the flow being measured, such that the frequency of oscillation is proportional to the rate of flow. A proportional fluid amplifier has a power stream input and one output connected in the feedback path of a NOR-type oscillator, and the flow being measured is applied as a control input signal to the amplifier to effectively vary the RC time constant of the feedback path. The oscillator produces fluid output pulses at a rate proportional to the flow being measured, and these pulses are counted to provide a digital indication of the flow rate.

Fluid flow transfer device

Abstract: Materials are transported through a conduit by the action of an impelling fluid introduced at a low mass flow rate and high velocity into the conduit. The impelling fluid enters the conduit along the inside wall surface with a velocity vector parallel to the flow path of the conduit for smooth transfer of energy to a compatible carrier fluid under laminar flow conditions.

Apparatus for calibrating a volumetric flow metering device

Abstract: Apparatus for use in the calibration of volumetric flow metering devices, such as metering pumps, comprises a hollow receptacle divided into two separate chambers by a moveable wall member, one of the chambers being adapted to receive fluid from the flow metering device and the other being filled with a calibrating liquid and connected to a vessel for receiving the calibrating liquid and measuring the volumetric rate at which it is received. In calibrating a metering device, the outlet from the device is connected to the inlet of the fluid-receiving chamber and fluid flowing through the metering device discharges into this chamber and, after filling it, causes the moveable wall member to displace the calibrating liquid in the adjacent chamber at a rate commensurate with the flow rate through the metering device.

Time-dependent flow of quasi-linear viscoelastic fluids

Abstract: Transient flow behavior of an incompressible quasi-linear viscoelastic fluid under suddenly applied constant pressure as well as under a periodic pressure gradient was investigated using a three-parameter relaxation function. In the light of these solutions, the roll of viscoelastic relaxation in the overshooting of volumetric flow rate and the effect of viscoelastic parameters on the mean square velocity profile are discussed.

Continuous v/l measuring

Abstract: The ratio of vapor to liquid volumes produced by a volatile liquid like gasoline, is determined at selectable temperatures by moving a stream of the liquid at a precisely maintained rate and measuring flow rate evolved vapor. Such vapor flow rate gives desired ratio directly, and is preferably measured by laminar flow meter or mass flow meter or the like, to produce an output proportional to the volume rate of flow and readable as electrical signals. A series of protective safeguard devices guard against hazards and against being misled by a signal obtained while operating conditions are not proper.

Theoretical and Experimental Study on the Use of Gas Chromatography in Turbulent Flow Conditions

Abstract: It is relatively easy to carry out gas chromatographic analysis under conditions where the carrier gas flow is turbulent if open tube columns are used. This speeds up the mass transfer in the mobile gas phase. Conditions necessary to reach the turbulent flow region are given and equipment ia described. It is shown theoretically that in the fully turbulent flow of gas the retention times of all compounds should be independent of inlet pressure and of the carrier gas flow rate to the extent that the partition coefficients are themselves pressure independent, and the carrier gas ideal. Also, the HETP should be constant for all compounds, and for inert peak equal to about 5 times the column radius. Experimental data fully support these theoretical results. When the flow velocity is larger than the critical Reynolds number, the retention time decreases only slightly with increasing column inlet pressure, and the HETP decreases smoothly towards a limiting value equal to about 6r 0. The efficiency for r...

Analytical study of colloid annular thrusters

Abstract: Colloid annular thrustor performance, using low mass flow rate data and space charge formulas

Flow rate control method

Abstract: The flow rate of a fluid through a conduit, in which solids buildup occurs, is controlled by introducing a time varying signal to a valve to control the rate of flow. The changes in fluid flow caused by the time varying signal act to flush out solids which have built up in the valve and/or conduit. The mean rate of flow is measured and maintained at a desired level by controlling the average valve opening.