• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1680-1686
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• 2009

Flow characteristics of a differential pressure flow meters which have a shape of triangular separate bar (TSB) was investigated according to machining conditions in pressure tapping holes. Size of pressure tapping holes is machined with either 1.0 mm or 1.5 mm in diameter. Also, number of pressure tapping holes are drilled either 9 or 17. The mass flow rate of the TSB flow meters are calibrated with a laminar flow meter by connecting them in line. The mass flow rate in the TSB flow meters are plotted with a non-dimensional parameter H which includes the gas temperature, exhaust gas pressure and differential pressure at the flow meters, and atmospheric pressure. An empirical correlation between the mass flow rate at the TSB flow meter and the non-dimensional parameter H was obtained. The empirical correlation showed highly linear relationship between the mass flow rate and the non-dimensional parameter H. The hole size of the pressure tapping holes has a bigger effect on the flow rate than the number of the tapping holes.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.563-568
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• 2007

A separate triangular bar type differential pressure flow meter was developed for measuring exhaust gas flow rate from Diesel engine. Three kinds of the separate triangular bar flow meters whose aerodynamic angles are different one another are made and evaluated, respectively. The experimental results show that an aerodynamic shape has a effect on the pressure difference between upstream and downstream at the flow meter, that is, the thinner the shape of the separate triangular bar flow meter is, the smaller the pressure difference at the flow meter is. The separate triangular bar type flow meter was calibrated at both cold and high temperature of the gas flow. A burner system was designed for raising the gas temperature and it was well operated in controlling the gas temperature. An empirical correlation between mass flow rate and differential pressure at the separate triangular bar flow meter was obtained and the empirical correlation was also corrected by the gas temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.363-364
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• 2008

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.334-335
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• 2004

It is important that the contaminated air is not revealed to the outside of the facility. The inside of the facility should be classified into several zones according to the radioactivity and each zone should maintain tile differential negative pressure between the zones also. It is not easy to equilibrate the pressure during the operation. On the normal operation, the clogging of the HEPA filter and the opening of the doors/shutters influence very much. We could maintain the differential negative pressure between the zones by the constant watching and periodical replacement of the filters.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.384-390
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• 2013

The sizes of cryogenic vessels and storage tanks are becoming bigger due to strong demands from semiconductor and LCD industry as well as high-tech electronic industry. Conventional level and pressure gauges used for cryogenic vessels were analog types which made exact measurement difficult for the remained quantity at lower levels due to their poor accuracy. In this study, a design for a digital type gas level gauge which can measure the pressure and level inside of the cryogenic liquefied gas storage tanks has been proposed by using a differential pressure sensor, in which the measured data are monitored by a host PC and are transferred to a mobile printer for data confirmation at local station.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.4
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• pp.47-56
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• 2005

In GPS/INS/barometer navigation system for UAV, vertical channel damping loop was introduced to suppress divergence of the vertical axis error of INS, which could be reduced to the level of accuracy of pressure altitude measured by a pitot-static tube. Because static pressure measured by the pitot-static tube depends on the speed and attitude of the vehicle, static pressure error models, based on aerodynamic data from wind tunnel test, CFD analysis, and flight test, were applied to reduce the error of pressure altitude. Through flight tests and sensitivity analyses, the error model using the ratio of differential pressure and static pressure turned out to be superior to the model using only differential pressure, especially in case of high altitude flight. Both models were proposed to compensate the effect of vehicle speed change and used differential and static pressure which could be obtained directly from the output of pressure transducer.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.214-214
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• 2007

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.51-56
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• 2017

In this paper, we have developed a differential pressure flow sensor designed as a single capacitive type. And the sensor was fabricated using a MEMS process. Differential pressure flow sensors are the most commonly used sensors for industrial applications. The sensing diaphragm and bonding joint of the MEMS pressure sensor are easily broken at high pressure. In this paper, we proposed a structure in which the diaphragm of the sensor was not broken at a pressure exceeding the proof pressure, and the differential pressure sensor was designed and manufactured accordingly. The operating characteristics of the sensor were evaluated at a pressure three times higher than the sensor operating pressure (0-3 bar). The developed sensor was $3.0{\times}3.0mm$ and measured with a LCR meter (HP 4284a) at a pressure between 0 and 3 bar. It showed 3.67 pF at 0 bar and 5.13 pF at 3 bar. The sensor operating pressure (0-3 bar) developed a pressure sensor with hysteresis of 0.37%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.1-8
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• 2018

In this study, a small-scale siphon breaker experimental facility was designed to examine the validity of the Siphon Breaker Simulation Program (SBSP). To design the experimental facility, the simulation results of the C factor, Chisholm B coefficient, and Undershooting Height (UH) were obtained by SBSP. The major parts of the experimental facility were the upper tank, lower tank, downcomer, and Siphon Breaker Line (SBL). The area of the Upper tank was $0.09-m^2$ with a height of 0.65-m. The height of the downcomer was 1.6-m. Pressure transmitters and an electronic scale were used to obtain the experimental results. The experimental variables were the sizes of Loss of Coolant Accident (LOCA) and SBL. The experimental results were analyzed by UH. The SBSP well predicted the UH with an error of 2.5%. Overall, it is possible to design siphon breakers with various scales using SBSP.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.47.2-47.2
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• 2005