Topic
Thermal mass flow meter
About: Thermal mass flow meter is a research topic. Over the lifetime, 1759 publications have been published within this topic receiving 21878 citations.
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Patent•
09 Apr 2010TL;DR: In this paper, a mass flow controller including a thermal mass flow sensor including at least two sensing elements coupled to a sensor tube of the Mass Flow Controller is described, which is designed to provide a first signal indicative of flow of a gas within a first flow-rate-range and a second signal indicating the flow of the gas inside a second-rate range.
Abstract: A mass flow controller among other embodiments and method is described. The mass flow controller including a thermal mass flow sensor including at least two sensing elements coupled to a sensor tube of the mass flow controller, the thermal mass flow sensor being designed to provide a first signal indicative of flow of a gas within a first flow-rate-range and a second signal indicative of flow of the gas within a second flow-rate-range; and a control portion figured to control a valve position of the mass flow controller responsive to the first signal when the flow of the gas is within the first flow-rate-range and control the valve position of the mass flow controller responsive to the second signal when the flow of the gas is within a second flow-rate-range.
30 citations
TL;DR: In this paper, the use of a capillary tube mass flow meter for measuring residential natural gas consumption, where the flow rate is extremely low, was proposed, and the simulation was accomplished for a sample natural gas composition with 94.38% methane, resulting to an uncertainty equal to 1.83%.
30 citations
Patent•
26 Sep 2008
TL;DR: In this article, a system and method for operating a mass flow controller thermal sensor is described, where each sensor provides a signal to a digital controller or other processing unit and the controller calculates the mass flow rates of a gas flowing through the unit as measured by sensors.
Abstract: A system and method for operating a mass flow controller is described. One embodiment validates the operation of a mass flow controller thermal sensor, including detecting zero drift and span drift in the sensor by comparing the thermal sensor output to a pressure sensor output. In one embodiment, each sensor provides a signal to a digital controller or other processing unit and the controller calculates the mass flow rates of a gas flowing through the unit as measured by the sensors. The mass flow rates may then be compared to determine if one of the thermal sensor is operating properly.
30 citations
TL;DR: In this article, a measurement correlation was established based on the differential pressure generated across the Venturi tube and the frequency extracted from the vortex flowmeter signal, which provided a simple and practical solution to the mass flow measurement of homogeneous gas-liquid bubble flows.
Abstract: Development of effective techniques for gas–liquid two-phase flow measurement is of interest to both academic research and industrial applications. This paper presents a novel approach to the measurement of the mass flow rate of homogeneous gas–liquid bubble flow with the combined use of a Venturi tube and a vortex flowmeter. The Venturi tube and the vortex flowmeter were mounted in the same pipeline with a spacing interval of ten times the pipe's inner diameter. A measurement correlation was established based on the differential pressure generated across the Venturi tube and the frequency extracted from the vortex flowmeter signal. Experiments were conducted on a vertical upward gas–liquid two-phase flow rig under the bubble flow pattern, with the air mass flow rate from 0.2 × 10−3 to 3.2 × 10−3 kg s−1, the water mass flow rate from 3.3 to 5.2 kg s−1 and the volumetric void fraction from 0.004 to 0.246. The results show that the relative errors of the correlation for the mixture mass flow rate measurement were within ±5%, and the maximum standard deviation of the relative errors was 2.0%. This method provides a simple and practical solution to the mass flow measurement of homogeneous gas–liquid bubble flows.
30 citations
Patent•
06 Nov 1995
TL;DR: In this article, a microcontroller-based processing circuit is employed to measure the capacitance of the probe sensors, and the circuit employs high speed timer and counter circuits to provide a high resolution measurement of the time interval required to charge each capacitor in the probe assembly.
Abstract: A quality and/or flow meter employs a capacitance probe assembly for measuring the dielectric constant of flow stream, particularly a two-phase flow stream including liquid and gas components. The dielectric constant of the flow stream varies depending upon the volume ratios of its liquid and gas components, and capacitance measurements can therefore be employed to calculate the quality of the flow, which is defined as the volume ratio of liquid in the flow to the total volume ratio of gas and liquid in the flow. By using two spaced capacitance sensors, and cross-correlating the time varying capacitance values of each, the velocity of the flow stream can also be determined. A microcontroller-based processing circuit is employed to measure the capacitance of the probe sensors. The circuit employs high speed timer and counter circuits to provide a high resolution measurement of the time interval required to charge each capacitor in the probe assembly. In this manner, a high resolution, noise resistant, digital representation of each of capacitance value is obtained without the need for a high resolution A/D converter, or a high frequency oscillator circuit. One embodiment of the probe assembly employs a capacitor with two ground plates which provide symmetry to insure that accurate measurements are made thereby.
29 citations