Showing papers on "Thermal mass flow meter published in 1980"

Calibratable system for measuring fluid flow

Abstract: A pair of mass flow sensors are used to separately monitor the mass flow rates of a carrier gas and of a mixture of carrier gas and source vapor formed a mixing station. The rates are compared, for example by substracting the carrier gas flow rate from the mixture flow rate, to generate a signal representing the mass flow rate of the source vapor. Flow of the carrier gas to the mixing station is modulated in accordance with the difference between this signal and a command signal representing a predetermined flow rate. The system can be calibrated by flowing the carrier gas alone through both sensors, by passing the mixing station, and adjusting the signal for one or both sensors so that the signals from both sensors are equalized.

Mass flowmeter with sensor gain control

Abstract: A mass flow rate meter is provided having two U-shaped tubular flow loops, means for vibrating the flow loops like the tines of a tuning fork Opto-electrical sensors on opposite legs of the flow loops generate signals indicative of the times between the passing of the sides of the loop through the static plane of the loop The times between the passing of the sides of the loops through the static plane may be combined to derive the mass flow rate of material flowing through the loops Means are provided for varying the gain of the opto-electrical sensors to provide for a constant performance under conditions of changing temperature, voltage variations and aging characteristics

Compound liquid flow meter

Abstract: A compound liquid flow meter comprised of a main flow path incorporating a turbine meter (2,36) and a downstream valve (3,24), and a parallel auxiliary low flow path incorporating a relatively small capacity meter (8,41) and a fixed orifice (16,53) discharging into the main flow path downstream of the valve. The orifice size is selected to cooperate with the diameter and spring characteristics of the valve so that on increasing flow rates the valve begins to open at 45 to 55 percent of the capacity of the low flow meter (8,41) and on decreasing flow begins to close at the same flow rate. The valve action is smooth and does not require, or create, pressure impulses or surges. Furthermore, the balanced relationship between the orifice and the valve virtually eliminates the traditional loss of accuracy associated with the "change over" of prior art compound meters. The valve actuation point is the same at increasing or decreasing flows and the valve is extremely simple containing no links, pivots, cams, or other items requiring adjustment or maintenance. A valve (15) may be connected in the low flow path and operated to limit the flow through that path when the downstream valve (2,24) is open and the flow through the main path is consequently high.

Quantity of flow meter

Abstract: A quantity of flow meter, includes two electrical conductors which are traversed by current and are physically traversed by a flowing medium to be measured. The increase of the current required for maintenance of the temperature difference between the two conductors is evaluated as a measurement of the quantity of flow. The meter is particularly versatile and can be employed for a wide voltage range and includes resistors as the electrical conductors which are thin resistor layers applied upon a thin carrier.

Method and a meter for measuring quantities of heat

Abstract: A method and a meter for measuring the quantity of heat abstracted from a circulating flow of liquid by a consumption unit. Indirect measurement of the volume flow rate of the liquid is made, while maintaining a sub heat flow (Q shunt) from or to the main heat flow transported by the flow of liquid and measuring the temperature at some points by means of temperature sensors (4). The volume flow rate of the flow of liquid is determined on the basis of the flow rate dependent heat transfer in the boundary layer (7) of the flow of liquid at the location, where the sub heat flow (Q shunt) leaves or enters, by determining the temperature differential (ΔT i ,b) across the boundary layer, and the sub heat flow (Q shunt) passing through said boundary layer (7). At least one absolute temperature of the flow of liquid is measured for correcting the temperature dependency of the material constants of the liquid involved in said determination of the volume flow rate.

Device for measuring the mass flow and the heat flow and method for determining the mass flow

Abstract: To measure the heat flow and the mass flow in a conveying system for fluids, a device is used which consists of (i) two fluid-carrying tubes, one mounted in the feed line and one in the return line, (ii) a heat-conducting section between these two tubes and (iii) temperature sensors. The heat-conducting section is made of material of low thermal conductivity, e.g., glass or a composite such as enamel or plastic-coated steel. It is designed such that the heat transmission through the heat-conducting section is lower than the heat transfer at the two interfaces between the fluid and heat-conducting section. At or close to the ends of the two heat transfer zones in the feed and return lines the temperatures or temperature differences of the fluid are measured and the heat flow or mass flow is derived from the results of these measurements.

The calibration of heat flow meters

Abstract: The heat flow meter electromotive force is first expressed as a function of the heat flow meter thermal conductivity and its correlation with temperature and density, as a function of the thermoelectric voltage of the couples of junctions of the thermopile in the heat flow meter, and as a function of the modulus of elasticity of the material used to build the heat flow meter. This relationship can define a heat flow meter model useful for predicting the range of operating conditions. The second step is to assume a model for the reference specimen used in the calibration, in order to set limits of thickness, thermal conductivity, temperature difference, and mean specimen test temperature, once the calibration accuracy is defined. The last step is to compare the calibration of the heat flow meters, using a double-specimen reference sample in a heat flow meter apparatus with a single meter and a single specimen, two meters and a single specimen, or a single meter between two specimens. The paper also gives an account of the speed and edge heat losses: moreover, the reader is cautioned against some possible errors in the use of the heat flow meters and in the interpretation of measured data.

Solids-concentration measurement and flow measurement of slurries and sludges using ultrasonic sensors with random data analysis: Part 2: Flow-velocity measurement

Abstract: The flow velocity is measured by cross- correlating the output signals from two axially spaced ultrasonic sensors, similar to the sensors described in Part 1 of this paper.A meter factor of 0.84 ± 0.02 was observed to calibrate the measured cross- correlation velocity against actual mean flow velocity, for flow of Reynold's number from 3× 10 3 up to 75 × 103. The meter performance was not affected by change in particle size and concentration; small quantities of gas bubbles (up to 5% by volume) do not affect the calibration curve.

Method of measuring flow rate and coriolis force type flow meter

Abstract: Method and apparatus for measuring mass flow, and particularly the sum or difference in mass flow of distinct streams of flowing materials, wherein a plurality of channels are provided in one or more conduits rotating or oscillating as a common unit with additive streams or a common stream being flowed through the channels in a first direction and subtractive streams being flowed through the channels in an opposite direction, and in which the net Coriolis force imposed upon the conduit unit is measured.

The Tribo-Electric Effect of Liquid Flow and Its Applications

Abstract: : The flow of liquids through dielectric tubes is shown to produce a frictional electromotive force, and an empirical relation is established between the voltage generated and the various experimental factors controlling it. The application of the effect to the measurement of the flow rate and the electrical resistivity of fluids is discussed.