Showing papers on "Thermal mass flow meter published in 1985"

Apparatus and method for continuously measuring mass flow

Abstract: An apparatus and method for measuring mass flow rate which utilizes a pair of parallel conduits having fixed ends. A driving mechanism is connected between the conduits near their mid-point for applying transverse oscillations to the conduits at a selected frequency. The fluid whose mass flow rate is to be measured is divided roughly equally and supplied through the parallel conduits. A motion sensor upstream of the driving mechanism and another one downstream of the driving mechanism produce signals which have the same frequency as the driving frequency but which lead or lag the driving frequency with regard to phase. This difference in phase is a measurement of mass flow rate. The apparatus can be constructed to self compensate for changes in temperature and/or thermal gradients.

Method and apparatus for determining mass flow rate and quality in a steam line

Abstract: A method and/or apparatus for determining the mass flow rate and the quality of steam in a flowing line. It involves directing the total flow to a liquid-vapor separator. The separated vapor and liquid have the flow of each metered and the flow of one regulated so as to hold the level of the separated liquid constant. Then, by measuring pressure and temperature of the separated flows upstream from the regulation, the mass flow rate and the quality of the steam may be determined.

Mass flow meter and signal processing system

Abstract: A signal processing system that directly determines the phase difference existing between two periodic electrical signals and a mass flow meter employing the system are provided. The system shifts together two comparison signals corresponding to the periodic electrical signals and accumulates the shift that is necessary to force the phase angles of the comparison signals to be equal. The mass flow meter employs a moving conduit through which the fluid whose mass flow rate is to be measured flows and which generates Coriolis forces. The Coriolis forces affect the motion of the moving conduit and motion sensors provide periodic signals corresponding to the motion of the conduit. Under flow conditions, the Coriolis forces cause the electrical signals produced by the sensors to be out of phase with each other to an extent that depends on the magnitude of the mass flow rate. The system provided by the invention is employed by the meter to measure the phase difference between the electrical signals to provide an indication of the mass flow rate through the moving conduit.

Immersed thermal fluid flow sensor

Abstract: An immersion-type thermal fluid flow sensor is disclosed in which the temperature dependent sensing resistor means is carried from a flexible ribbon-shaped septum immersed in the flow and arranged in a spiral, meander or other geometrical configuration to partition the total flow passageway into a plurality of parallel flow portions. In one embodiment, the partitioned flow passageways are dimensioned to have a length to cross-sectional dimension ratio for providing laminar flow conditions over the operating flow range of interest. In another embodiment, a heater is provided for heating the septum to a temperature near that of the sensing resistor to reduce the time constant of the flow measurement. In another embodiment, a thermal loading element is coupled in heat exchanging relation with the sensing resistors for increasing the critical flow rate and thus for increasing the operating range of the flow regime wherein the temperature difference ΔT between the upstream and downstream resistors is a direct function of mass flow rate. Also, in another embodiment, thermal gradient shields shield the flow sensing resistors from external thermal gradients.

Method of automatically measuring fluid flow rates

Abstract: A method comprises providing at least two fluid flow channels of different sizes wherein each contain a temperature sensitive resistance fluid flow sensor. An electronic controller is provided with the electrical information from the temperature sensitive resistance fluid flow sensor. The electronic controller is provided with a data base including at least the calibration data between fluid flow rate and the electrical information from the resistance sensor and the designated fluid flow rates at which each of the flow channels other than the smallest that could be opened or closed. Next, the fluid whose flow rate is to be measured is caused to flow through the smallest flow channel. Then the electronic controller compares the flow rate through the smallest flow channel with the designated flow rate for the smallest channel and opens the next larger flow channel to fluid flow if the designated flow rate is exceeded or closes such flow channel if such designated flow rate is not exceeded. If the next largest channel is to be opened, the proceeding three steps are repeated for each succeeding pair of flow channels until the flow rate does not exceed the designated flow rate or until there are no more flow channels to be opened. Finally, the flow rate information from all of the flow channels is combined.

A calibration system for the calibration of mass flow controllers.

Abstract: Calibration system for the calibration of mass flow controllers (MFC1, MFC2, MFC3) of an apparatus used for a chemical vapour phase growth. Practice has shown that already minor deviations of the characteristics of the mass flow controllers from the ideal may be very disadvantageous in the production of the preform of an optic fiber, for instance. For the elimination of said problems, the present system comprises at least one mass flow meter (MFM1, MFM2) for measuring the characteristics of the mass flow controllers (MFC1, MFC2, MFC3) and means for calculating correction coefficients for the different controllers. The system preferably comprises at least one flow meter (MFM1, MFM2) for measuring at least the adjoining ranges of the mass flow controllers (MFC1, MFC2) covering adjacent flow ranges.

Thermal mass flow meter and method of making same

Abstract: A thermal mass flow meter includes a comb-shaped structure having a plurality closely spaced septa carried from a common spine and disposed within the flow stream to be measured for partitioning the flow therein into a plurality of generally parallel elongated ribbon-shaped flow stream portions. Temperature-dependent fluid flow sensing resistor means is coupled in heat-exchanging relation predominantly with the narrow face of at least one of said ribbon-shaped flow stream portions for measuring the fluid flow. In a preferred embodiment, the comb-shaped flow partitioning structure is fabricated by anisotropically etching the parallel flow channels through the (110) face of diamond cubic material such as silicon. In another embodiment, a thermal loading member is disposed in heat-exchanging relation with the temperature dependent fluid flow sensing resistor means for thermally loading same and pushing the critical flow rate up to a higher flow to allow operation of the flow sensor in one mode of operation over a wider range of flow rates.

High‐pressure, thermal‐pulse, liquid flow meter

Abstract: A liquid flow meter for operation at high pressures is described. The meter uses a thermal pulse with time‐of‐flight detection to measure the flow rate. The thermal‐pulse generator and detector are located outside a metal capillary tube.

Mass Flow Measurement of Gravity Flow for High Temperature Dense Phase Solid Gas Two Phase Flow

Abstract: Moved bed gravity flow of solid is required for coal gasifier, metal ore direct reduction furnace, gas phase coal liquifier, etc. as energy conservation. Such a process is high pressure and or high temperature process and required for multi loop injection feeder. The authors developed a new noise flow meter for the process based on the authors' test and the prediction. The measuring method is an noninstrusive method using the simple lean noise sensors and sensing technique without sensing hole on the gravity flow pipe. The conclusion of the authors' test is that noise pressure level on 8kHz by C characteristics is suitable for the mass flow control without back ground noise calibration. Space filtering of the signal or cross correlation method of signal is more suitable for sensing technique. The sensor and senting technique is suitable for solid particle velocity meter of two phase transport pipe.

Float-type flow meter

Abstract: The invention relates to a float-type flow meter having a vertical, essentially tubular housing, through which the medium to be measured is to flow from the bottom to the top, and having a float which can be raised in a main flow channel, formed by the housing, by the flow of the medium, possibly against the action of a spring and possibly with continuous enlargement of a free flow cross-section, and is guided axially inside the housing In order to reduce the influence of the temperature and thus viscosity of the medium to be measured, the float-type flow meter is distinguished by a bypass channel which connects the inlet and outlet of the housing, which are separate from the main flow channel accommodating the float, and which has a valve arrangement which opens the bypass channel below a prescribed temperature of the medium to be measured and closes it above a prescribed temperature of the medium to be measured

Flow meter for measuring the flow rate of liquid

Abstract: A flow meter for measuring the flow rate of a liquid, capable of detecting the liquid level in the upstream space with respect to a weir and determining the flow rate of the liquid on the basis of the relationship between the liquid level and the flow rate of the liquid that flows through the weir, wherein the width of the weir is designed so that the ratio of the variation of the flow rate caused by a fixed variation in the liquid level to the total flow rate at the existing liquid level is constant regardless of the liquid level.

Calibration of sonic valves for the laminar flow control, leading-edge flight test

Abstract: Sonic needle valves were calibrated to measure and control airflow in the suction system for the leading-edge flight test. The procedure and results for the calibration flow test of 4:41 flight valves are given. Mass-flow rates, which ranged from 0.001 to 0.012 lbm/sec, and maximum back pressure were measured for total temperatures from -30 F to 75 F and total pressures from 120 to 540 psf. Correlating equations are obtained for mass-flow rate as a function of total pressure, total temperature, and valve opening length. The most important aspect of flow measurement and control is found to be the measurement of valve opening length.