• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.2
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• pp.63-70
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• 2003

In this paper, an MFC (Mass Flow Controller) which is widely used in many semiconductor manufacturing processes for controlling the mass flow rate of a gas is designed and implemented using the PIC 16F876 of Microchip, Inc. The MFC implemented in this thesis has the form of hybrid-type, i.e., the mixed-type of the analog-type MFC, which has many problems such as low accurary, and digital-type MFC, which use an expensive DSP (Digital Signal Processor) and an ADC (Analog to Digital Convertor) with high precision. The MFC is consists of the sensor unit, the control unit and the actuator unit, and it has used the automatic calibration algorithm and the reference table method for the improvement of the performance.

• 연구논문집
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• s.22
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• pp.85-96
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• 1992

A mass flow controller(MFC) is commonly used in the semiconductor industries to control the flow rate of various process gases. The measurement and precise control of the of flow rate the gas are the key for a succesful IC fabrication. To eventually design a reliable MFC, a pre-proto type MFC was built and its flow characteristics were investigated. Most of the functional components of the pre-proto type were built for the present study, but the remainder were adopted from a commercial unit. The flow control characteristics were compared with that of a standard MFC. Major dimensions of an MFC for 0-10 SLM capacity were suggested.

• Journal of Biomedical Engineering Research
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• v.42 no.4
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• pp.193-200
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• 2021

Flowmeter and oxygen sensors are listed in COVID-19 essential medical devices. This article reports a Teensy microcontroller-based Oxygen mass flow controller (MFC), core part of the oxygen respirator or extracorporeal membrane oxygenation (ECMO). The developed MFC consisting of the microcontroller, MEMS flow sensor, and solenoid valve was able to accurately control 0 to 100 sccm of oxygen flow rate. The pressure of vacuum chamber increased proportionally to the flow rate (0.998 of Pearson correlation coefficient). The experimental results proved that the developed MFC exhibits comparable performance to a commercial MFC in accuracy, settling time, linearity with pressure, and repeatability of oxygen mass flow control. It is expected that this simple and cheap MFC is utilized for oxygen therapy against the severe acute respiratory syndrome coronavirus 2.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.595-600
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• 2001

Thermal mass flow meter(TMF) and thermal mass flow controller(MFC) were used to measure and to control the mass flow rate of gases. TMF and MFC were designed for specified working pressure and gas. For the case of different working pressure and gases, the flow rate measurement accuracy decreased dramatically. In this study, a TMF and MFC was tested with three different gases and pressure range from 0.2 MPa up to 1.0 MPa. Effect of specific heat causes to increase flow measurement error as much as ratio of specific heat compared with reference gas. Changing of pressure causes to increase flow rate measurement error about -0.2% as the working pressure decreased 0.1 MPa. Response time of MFC was below 3.12 s for the case of increasing of flow rate. But the response time was increased up to 6.92 s for the case of decreasing of flow rate. When the solenoid valve was fully closed, a initial delay time of output of MFC was increased up to 1.36 s.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.1
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• pp.19-25
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• 2007

The MFC(Mass Flow Controller) is an equipment that measures and controls mass flow rates of fluid. Most of the HFC system is still using the PID algorithm. The PID algorithm shows superior performance on the MFC system. But the PID algorithm in the MFC system has a few problems as followed. The characteristic of the MFC system is changed according to the operating environment. And, when the piezo valve that uses the control valve is assembled in the MFC system, a coupling error is generated. Therefore, it is very difficult to find out the exact parameters of MFC system. In this paper, we propose adaptive PID algorithm in order to compensate these problems of a traditional PID algorithm. The adaptive PID algorithm estimates the parameters of MFC system using LMS(Least Mean Square) algorithm and calculates the coefficients of PID controller. Besides, adaptive PID algorithm shows better transient response because adaptive PID algorithm includes a feedforward. And we implement MFC system using proposed adaptive PID algorithm with self-tuning and Ziegler and Nickels's method. Finally, comparative analysis of the proposed adaptive PID and the traditional PID is shown.

• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.99-106
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• 2010

In this paper, we propose an industrial fluid monitoring system which performs the flow control function and monitors fluid pressure transmitted from MFC(Mass Flow Controller) unit. This system consists of MFC unit, channel device, and monitoring management software. MFC unit transmits the measured data of the fluid pressure to the channel device which would provide the input/output interface between management software, monitoring and MFC unit. The monitoring and management software control and analyze by monitoring real time measurements of fluid pressure from each channel of MFC unit. This software can process 20 channels and 0.1 monitoring cycle which gives 200 data measurement per second (i.e., 720,000 data/hour). At this time, the storage space increases in proportion to the rise of input data. This growth of data and storage space makes loss of data access efficiency. Therefore, it demands the implementation by sensing scheme of change scope and data, which can effectively manage the data.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.3
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• pp.531-537
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• 2004

In this paper, the static and dynamic characteristics in the sensor tube of a mass flow controller(MFC) were studied by experiments. In the sensor tube of MFC. the difference of temperature between inlet and outlet was necessary for calculating the mass flow rate. Therefore, the relations among flow rate, heat generated by heating wire. and sensor location were investigated to find optimized condition. Finally, the relation between sensor voltage through analog digital conversion(ADC) and flow rate in the sensor tube can be represented. Based on this study, static and dynamic characteristics of sensor tube can be used for design of mass flow controller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.893-894
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• 2013

• Journal of Power System Engineering
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• v.7 no.3
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• pp.35-39
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• 2003

In this paper, the heat transfer phenomena in the sensor tube of a mass flow controller(MFC) were studied by experiments. In the sensor tube of MFC, the difference of temperature between inlet and outlet was necessary for calculating the mass flow rate. Therefore, the relations of flow rate, generated heat by heating wire, sensor location and tube thickness were investigated to find the optimized condition. Based on this study, static and dynamic characteristics of sensor can be used for mass flow controller.

• Journal of the Semiconductor & Display Technology
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• v.7 no.2
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• pp.55-58
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• 2008

The objective of the research is to design, manufacture and test a Mass Flow Controller(MFC) capable of measuring compressible fluid flows based on a "bucket and stop-watch"method. The basic principle is the measurement of time, where the time taken to fill and empty a bucket of known volume is measured. This method of flow measurement is a new concept when compared to a commercilized current mass flow controller. For the flow meter to be able to compete with established designs it not only must be comparable in cost and robustness, it must be very accurate and reliable as well. This device should be able to handle fluid flows in the range of 0.1ml/min to 10ml/min within an accuracy of ${\pm}$1%. A possible application for a device such as this is in electronics industry where arsenic gas is used in the production of silicon chips.