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.

Method and apparatus for measuring ratio of mass flow rates and energy flow in a gas pipeline

Abstract: The present invention is a method and apparatus for monitoring in real time the mass and energy flow rate of a gas through a pipeline The invention determines the mass flow ratio of a pipeline gas flowing through a pipeline compared to sample gas tapped from the pipeline line when the volumetric flow of pipeline gas through the pipeline is measured by a linear flow meter Sample gas tapped from the pipeline is flowed to a chamber having a section with a fixed volume until the pressure in the chamber section is substantially equal to the pipeline gas pressure The sample gas is maintained at substantially the same temperature as the gas in the pipeline while the sample gas is in the chamber section A timer measures the time interval for the sample gas to flow from the chamber section at a selected rate for a calculated pressure drop the selected rate being controlled by a flow controller The mass flow ratio is computed using the measured time interval and a signal from the linear flow meter The energy flow rate of the pipeline gas is determined by measuring the energy flow rate of the sample gas and relating that value to the mass flow ratio of the pipeline gas compared to the sample gas

Mass flow rate controller, assay method therefor, and semiconductor manufacturing equipment

Abstract: PROBLEM TO BE SOLVED: To provide mass flow rate controller which enables high-accuracy assay by reflecting both pressure and mass flow and also allowing for variation in tank volume. SOLUTION: This is the method for assay of the mass flow rate controller which comprises a valve for assay 42 installed in utmost upstream of channel 6, mass flow rate control valve mechanism 10; tank 44 mounted on the channel 6 of upstream from the mass flow rate control valve mechanism 10; mass flow detecting means 8, pressure detecting means 46, means 18 for controlling the mass flow rate control valve mechanism 10, and mass flow rate assay control means 48. The method includes (1) streaming the fluid of a defined mass flow rate to the channel 6, (2) for maintain opening of the mass flow rate control valve mechanism 10 so as to match the mass flow of the fluid with the defined mass flow; (3) closing the valve for assay 42, (4) for measuring pressure and mass flow rate of the fluid after flow of the fluid running out from the tank 44 is stabilized; (5) calculating the rate of change in pressure and mass flow rate with respect to the reference pressure and mass flow measured by the same procedure in the initial state, and then (6) conduct assay, depending on the rate of change. COPYRIGHT: (C)2008,JPO&INPIT

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