• Title/Summary/Keyword: Pressure

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Development of Pressure Monitoring System Using Silicon Pressure Sensor (실리콘 압력센서를 이용한 압력 모니터링 시스템 개발)

  • Lee, Young Tae;Kwon, Ik Hyun
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.4
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    • pp.76-79
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    • 2018
  • In this paper, we developed a pressure monitoring system using silicon pressure sensor. The pressure monitoring system was developed on the basis of a microcontroller, and a self-developed silicon pressure sensor was applied. The pressure monitoring system outputs the current pressure value via UART communication. In addition, it includes a function of displaying by LED when the preset three-step pressure (low, medium, high pressure) is reached. The silicon pressure sensor used in the pressure monitoring system was set to 0 kPa, 10 kPa, 26 kPa, and the pressure monitoring system was evaluated because the measured maximum pressure was in the range of 100 kPa.

The Study on Sizing of the Pressure Relief Valve for Overpressure Protection of a Reactor Pressure Vessel in Low Temperature Condition (저온 상태의 원자로 압력용기의 과압방지를 위한 압력방출밸브 용량 결정에 관한 연구)

  • Lee, Jun;Kim, Yoo
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.4 no.2
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    • pp.7-12
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    • 2008
  • The purpose of this study is to present a methodology to estimate the capacity of the pressure relief valve which prevents overpressure of the pressure vessel in a cold state. In this methodology, the transient behavior of the flow rate through the pressure relief valve and the pressure inside the pressure vessel are considered. The result of this study shows the followings; The more the relief valve capacity is considered in excess, the more the initial relief flow rate and the initial pressure inside the pressure vessel are high and low respectively. When the relief valve capacity is determined properly, the pressure inside the pressure vessel maintains almost the same value, so the ASME code requirement will be met.

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Borehole stability analysis in oil and gas drilling in undrained condition

  • Wei, Jian-Guang;Yan, Chuan-Liang
    • Geomechanics and Engineering
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    • v.7 no.5
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    • pp.553-567
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    • 2014
  • Borehole instability during drilling process occurs frequently when drilling through shale formation. When a borehole is drilled in shale formation, the low permeability leads to an undrained loading condition. The pore pressure in the compressed area near the borehole may be higher than the initial pore pressure. However, the excess pore pressure caused by stress concentration was not considered in traditional borehole stability models. In this study, the calculation model of excess pore pressure induced by drilling was obtained with the introduction of Henkel's excess pore pressure theory. Combined with Mohr-Coulumb strength criterion, the calculation model of collapse pressure of shale in undrained condition is obtained. Furthermore, the variation of excess pore pressure and effective stress on the borehole wall is analyzed, and the influence of Skempton's pore pressure parameter on collapse pressure is also analyzed. The excess pore pressure decreases with the increasing of drilling fluid density; the excess pore pressure and collapse pressure both increase with the increasing of Skempton's pore pressure parameter. The study results provide a reference for determining drilling fluid density when drilling in shale formation.

A Study on the Method of Equilibrium-Pressure Prediction from Transient Data (과도상태의 압력데이터로부터 평형상태 압력 예측방법 연구)

  • Lee, Jong-Kook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.7
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    • pp.19-28
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    • 2004
  • This study is concerned with the method of equilibrium-pressure prediction from transient data. Pressure measurement system consisted of pressure sensor and pressure tube. The surface orifice where pressure is measured is connected to a pressure sensor by a tube. In case of high orifice pressure, the pressure sensor responds rapidly to the orifice pressure. But when the orifice pressure is low the pressure sensor does not respond rapidly to the orifice pressure and time lag occurs seriously. Various test conditions are applied to investigate the time lag and to assess the methods of equilibrium-pressure prediction. The test time of the low-pressure measurement can be reduced by the method of equilibrium-pressure prediction of the present study.

Variations of Temperature and Pressure in the Cavity for Operational Conditions of Injection Molding (사출성형의 공정변수에 따른 캐비티 내의 온도와 압력의 변화)

  • Kim S. W.;Park H. C.;Lyu M.-Y.;Jin Y. S.;Kim D.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.70-74
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    • 2004
  • Pressure and temperature in the cavity of injection molding have been investigated. Special injection mold was designed to install pressure and temperature sensors. The sensors were supplied by KISTLER and the pressure and temperature were measured for various operational conditions, such as injection pressure, holding pressure, cooling time, mold temperature, and injection temperature. As injection pressure increased cavity pressure and temperature increase. There were no big differences in temperatures according to the holding pressures. As mold temperature increased pressure and temperature in the cavity increase. The flowability of resin increases as mold temperature increases subsequently the pressure in the cavity increases since the pressure loss is less in the low viscous medium than high ciscous medium. The cavity temperature highly depends upon mold temperature.

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Estimation of Target and Completion Pressure during the Cuff Inflation Phase in Blood Pressure Measurement (혈압측정시 가압 단계에서 목표압력 및 측정 종료압력 추정)

  • Oh, Hong-Sic;Lee, Jong-Shill;Kim, Young-Soo;Shen, Dong-Fan;Kim, In-Young;Chee, Young-Joan
    • Journal of Biomedical Engineering Research
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    • v.29 no.5
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    • pp.371-375
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    • 2008
  • In blood pressure measurement, the oscillometric method detects and analyzes the pulse pressure oscillation while deflating the cuff around the arm. For its principle, one has to inflate cuff pressure above the subject's systolic pressure and deflate below the diastolic pressure. Most of the commercialized devices inflate until the fixed target pressure and deflate until the fixed completion pressure because there is no way to know the systolic and diastolic pressure before measurement. Too high target pressure makes stress to the subject and too low target pressure makes big error or long measurement time because of re-inflation. There are similar problems for inadequate completion pressure. In this study, we suggest new algorithm to set proper target and completion pressure for each subject by analyzing pressure waveform while inflating period. We compared our proposed method and auscultation method to see the errors of estimation. The differences between the two measurements were -4.02$\pm$4.80mmHg, -10.50$\pm$10.57mmHg and -0.78$\pm$5.l7mmHg for mean arterial pressure, systolic pressure and diastolic pressure respectively. Consequently, we could set the target pressure by 30 mmHg higher than our estimation and we could stop at 20mmHg lower than our estimated diastolic pressure. Using this method, we could reduce the measurement time.

Differences in Blood Pressure among Adults in the Community according to Blood Pressure Measurement Time and Age (지역사회 성인의 혈압측정횟수 및 연령에 따른 혈압의 차이)

  • Park, Kyung-Yeon
    • Journal of Korean Biological Nursing Science
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    • v.21 no.4
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    • pp.275-282
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    • 2019
  • Purpose: This study aimed to identify the differences in blood pressure among adults in the community according to age and time of the blood pressure measurement. Methods: This was a secondary analysis study, using data from a 2015 community health survey, conducted by the Korea Centers for Disease Control and Prevention. The data of three-time-measured blood pressure were collected from 337 subjects, 25, 35, 45, 55, 65, 75 years old, which are median ages by each age group. Results: The primary systolic pressure was significantly higher than the secondary systolic pressure (t= 3.46, p= .001) and the tertiary systolic pressure (t= 4.83, p= .001). The secondary systolic pressure was higher than the tertiary measurement (t= 2.05, p= .041). There was no significant difference between the three-time-measured values for diastolic pressure. There was a significant interaction between measurement times and age in the systoic blood pressure readings (F= 1.95, p= .036). However, there was no significant interaction between measurement times and age in the diastolic blood pressure readings (F= 1.03, p= .418). Conclusion: The findings suggest that attention must be paid to the use of blood pressure values in studies or one-time-measured clinical blood pressure values. In particular, the differences in systolic pressure readings taken at different times in the older age groups were significant. Therefore, it is more important to carefully assess blood pressure in adults over the age of 45 compared to other age groups.

Variations of Air Temperature, Relative Humidity and Pressure in a Low Pressure Chamber for Plant Growth (식물생장용 저압챔버 내의 기온, 상대습도 및 압력의 변화)

  • Park, Jong-Hyun;Kim, Yong-Hyeon
    • Journal of Bio-Environment Control
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    • v.18 no.3
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    • pp.200-207
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    • 2009
  • This study was conducted to analyze the variations of air temperature, relative humidity and pressure in a low pressure chamber for plant growth. The low pressure chamber was composed of an acrylic cylinder, a stainless plate, a mass flow controller, an elastomer pressure controller, a read-out-box, a vacuum pump, and sensors of air temperature, relative humidity, and pressure. The pressure leakage in the low pressure chamber was greatly affected by the material and connection method of tubes. The leakage rate in the low pressure chamber with the welding of the stainless tubes and a plate decreased by $0.21kPa{\cdot}h^{-1}$, whereas the leakage in the low pressure chamber with teflon tube and rubber O-ring was given by $1.03kPa{\cdot}h^{-1}$. Pressure in the low pressure chamber was sensitively fluctuated by the air temperature inside the chamber. An elastomer pressure controller was installed to keep the pressure in the low pressure chamber at a setting value. However, inside relative humidity at dark period increased to saturation level.. Two levels (25 and 50kPa) of pressure and two levels (500 and 1,000sccm) of mass flow rate were provided to investigate the effect of low pressure and mass flow rate on relative humidity inside the chamber. It was concluded that low setting value of pressure and high mass flow rate of mixed gas were the effective methods to control the pressure and to suppress the excessive rise of relative humidity inside the chamber.

A Study on the Characteristic of Contact Pressure for CPB (Cold Pad Batch) Padder Roll Controlled by Hydraulic Single Cell (단일 유압 Cell로 제어되는 CPB(Cold Pad Batch)용 패더롤의 접촉압력 특성 연구)

  • Cho, Kyung-Chul;Lee, Eun-Ha;Jo, Soon-Ok;Park, Si-Woo;Hwang, Youn-Sung;Kim, Soo-Youn
    • Textile Coloration and Finishing
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    • v.29 no.2
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    • pp.86-96
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    • 2017
  • To make uniform pressure distributed over the contact surface was necessary to cold pad batch dyeing machine. In this study, to confirm characteristic of flexibility and the contact pressure distribution through experimental analysis of padder roll were controlled by hydraulic cell. When there were no load pressure only inner pressure, the value of displacement in the center of padder were greater than the end of the padder. The results of this study showed that the padder had the optimum value of inner pressure for uniform contact pressure distribution. Measuring the contact pressure in a padder system were driven by using a pre-scale film. Uniform contact pressure distribution of cell padder were a linearly with load pressure and inner pressure. When the load pressure was less than 8 tons, the inner pressure for the uniform contact pressure was 1~4 bar. The padder roll performance curves proposed in this study were available for practical production environments and various roll designs.