• Title/Summary/Keyword: Pressure regulation valve

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A Micro Shunt Valve with Anti-siphon Effect

  • Lee, Sang-Wook;Yoon, Hyeun-Joong;Yang, Sang-Sik
    • KIEE International Transactions on Electrophysics and Applications
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    • v.4C no.1
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    • pp.31-34
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    • 2004
  • This paper presents the fabrication and testing of a two-way pressure regulation micro shunt valve with an anti-siphon effect that can be implanted in hydrocephalus patients. This micro shunt valve consists of a silicone rubber membrane and a valve seat for the opening pressure control as well as the anti-siphon behavior. The two-way pressure regulation and the anti-siphon effect of the micro shunt valve are verified experimentally for various sizes of membranes and valve seats.

Analysis of Ratio Changing Characteristics of a Metal V-Belt CVT Adopting Primary Pressure Regulation (압력제어 방식 금속 벨트 CVT 변속특성 해석)

  • 최득환;김현수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.5
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    • pp.179-187
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    • 2001
  • In this paper, a primary pressure regulating type ratio control system is developed for a metal belt CVT, and the CVT ratio changing characteristics are investigated by simulation and experiment. The hydraulic part of the ratio control system has a simple structure with one 3-way spool valve as a main ratio control valve and one bleed type variable force solenoid as a pilot valve. The mathematical modelling of the CVT hydraulic system is derived by considering the CVT shift dynamics. Simulation results of CVT speed ratio and the primary pressure agree with the experimental results demonstrating the validity of the dynamic models. It is found from the simulation and experimental results that the response time of speed ratio and primary pressure can be shortened by increasing the ratio control valve port area, and the size of feedback orifice of ratio control valve gives a damping effect on the primary pressure oscillation.

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Liner Analysis of IMV Proportional Flow Control Valve Static Characteristics (IMV 비례 유량제어밸브 정특성 선형해석)

  • Jung, Gyuhong
    • Journal of Drive and Control
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    • v.16 no.4
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    • pp.56-64
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    • 2019
  • Recently, as the environmental regulation for earth moving equipment has been tightened, advanced systems using electronic control have been introduced for energy savings. An IMV(Independent Metering Valve), which consists of four 2-way valves, is one of the electro-hydraulic control systems that provides more flexible controllability and potential for energy savings in excavators, when compared to the conventional 4-way spool valve system. To fully realize an IMV, a two-stage bi-directional flow control valve which can regulate the large amount of flow in both directions, should be developed in advance. A simple design that allows proportional flow control to apply the pilot pressure from the current-controlled solenoid to the spring loaded flow control spool and thus valve displacement, is proportional to the solenoid current. However, this open-loop type valve is vulnerable to flow force which directly affects the valve displacement. Force feedback servo of which the position loop is closed by the feedback spring which interconnects the solenoid valve and flow control spool, could compensate for the flow force. In this study, linearity for the solenoid current input and robustness against load pressure disturbance is investigated by linear analysis of the static nonlinear equations for the IMV proportional flow control valve with feedback spring. Gains of the linear system confirm the performance improvement with the feedback spring design.

Safety Evaluation Based on Structural Analysis of Cylinder Valves for Fuel Cell Vehicles (구조해석을 이용한 수소 연료전지 자동차 압력용기 밸브의 안전성 평가)

  • Lee, Hyo Ryeol;Ahn, Jung Hwan;Shin, Jin Oh;Kim, Hwa Young
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.25 no.3
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    • pp.189-197
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    • 2016
  • Green vehicles include electric vehicles, natural gas vehicles, and fuel cell vehicles (FCVs). In FCVs, pressure vessels have cylinder valves to control hydrogen flow. These valves should be of high quality in terms of safety because hydrogen is stored at ultra-high pressure in pressure vessels. Hence, safety evaluation of these valves is necessary to secure the safety of the FCV. A structural analysis of the cylinder valve was conducted in this study by using a commercial finite element analysis code. The results showed that the safety factor of valve component ranged 1.06-186.44. After categorizing, the stress components at critical points of the cylinder valve parts were evaluated using the corresponding allowable design criteria in the ASME code. The pressurization cycle test was performed as per the regulation to evaluate the safety of the valve.

Study on Analytic of Opening Angles for Muffler Variable Valve of Automobile (자동차 머플러 내의 가변밸브의 열림 각에 관한 해석적 연구)

  • Park, Chungyeol;Kim, Kwonse;Kim, Jongil;Choi, Dooseuk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.2
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    • pp.190-196
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    • 2014
  • Exhaust system by reinforcement of environment regulation came to the foe study necessity. And Exhaust system has necessary to increase the engine performance and silence. From this cause, Automobile has significantly considered production expense. this study makes process for checking the characteristics about Exhaust variable valve within muffler. Variable valve might reduce the baffle within muffler, It was possible to remove the front muffler. Therefor, To miniaturize a size of muffler might be increased by performance through cost-cutting effect and controling of back pressure. Because the Study on Variable valve installed within muffler, to measure the real data was hardly resulted one of the assignments. From manufactured conduct device, might measure data one of piece which was up-graded of problem. Considering to these point, stressed pressure distribution has analyzed on cross section, floating characteristics about velocity distribution around variable valve using analysis as computational fluid dynamics of Ansys with completed measurement data.

Modeling and Design of an Active Pressure Regulating Valve(Implant) (녹내장 치료용 능동형 압력조절밸브(Implant) 모델링 및 설계)

  • Bae, Byunghoon;Kim, Nakhoon;Lee, Yeon;Kee, Hongseok;Kim, Seoho;Park Kyihwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.5
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    • pp.805-815
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    • 2001
  • Glaucoma is an eye disease which is caused by abnormal high IOP (Intra Ocular Pressure). High IOP is caused by the aqueous humor which is produced consistently but not drained due to malfunction of the trabecular system which has a role of draining the aqueous humor into the venous system. Currently, there are three methods to treat glaucoma-using medicines, surgical operation, and using implant device. The first and second methods are not long acting, so the use of implants is increasing in these days in order to drain out the aqueous humor compulsory. However, though conventional implants have a capability of pressure regulation, they cannot maintain IOPs desired for different patients, and too much aqueous humor are usually drained, to cause hypotony. To solve these problems, it is needed to develop a new implant which is capable of controling the IOP actively and copes with personal difference of patients. An active glaucoma implant consists of the valve actuator, pressure sensor, controller, and power supply. In this paper, firstly, we make an analysis of the operation of a conventional implant using a bond graph and show defects and limitations of the conventional valve analytically. Secondly, we design and analyze a valve actuator considering actuation principles, resistance elements, control methods, and energy sources focused on power saving problem. Finally, using simulations the possibility of the proposed valve actuator is investigated.

Fitness-for-Service Assessment for Instrument Valve Material by Tensile Test for Verification (계기용 밸브 재질의 검증 인장시험에 의한 사용적합성 평가)

  • In Hwan Shin;Chi Yong Park
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.17 no.1
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    • pp.49-55
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    • 2021
  • In this paper, an application example for fitness-for-service of material is shown. A kind of instrument valve is made of austenitic stainless steel fabricated by the cold working process. The tensile strength of the cold worked austenitic stainless steel has to be limited under 90 ksi to prevent the stress corrosion cracking in power plants. In industrial fields, tensile strengths of some materials were discovered to be over the regulation requirements in a certified material test report (CMTR). Owner's verification tests were performed to compare with that in a CMTR and to check the appropriateness. It is found that, in the case of verification test under the required test speed, valve materials could be used in the field. Although it is only one application sample of material check process in the power generation site, this case study could show an importance of basic experimental technology in academia and research circles.

Overflow Valve and Performance Evaluation System for Diesel Cars based on Spring Load (스프링하중을 고려한 디젤차량용 오버플로우 밸브 성능평가)

  • Yoon, Dal-Hwan
    • Journal of IKEEE
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    • v.20 no.2
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    • pp.200-204
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    • 2016
  • In this paper, we have estimated the performance of an overflow valve for EURO type CRDI(common rail direct injection) engine. In order to implement the overflow valve with friendly circumstance, it is necessity for considering spring load. Especially, the performance evaluation of diesel car with accuracy control will be considered a mileage improvement and circumstance regulation. In order to evaluate the performance of overflow valve, The leak test system checks the pressure, switching time and operating time under 3.0 bar below 100 cc, 3.3 bar among 150 cc and 200 cc, finally 4.0 bar upper 250 cc.

A Passive Flow-rate Regulator Using Pressure-dependent Autonomous Deflection of Parallel Membrane Valves (압력에 따른 평행박막 밸브의 자율 변형을 이용한 수동형 유량 제어기)

  • Doh, Il;Cho, Young-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.6
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    • pp.573-576
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    • 2009
  • We present a passive flow-rate regulator, capable to compensate inlet pressure variation and to maintain a constant flow-rate for precise liquid control. Deflection of the parallel membrane valves in the passive flowrate regulator adjusts fluidic resistance according to inlet fluid pressure without any external energy. Compared to previous passive flow-rate regulators, the present device achieves precision flow regulation functions at the lower threshold compensation pressure of 20kPa with the simpler structure. In the experimental study, the fabricated device achieves the constant flow-rate of $6.09{\pm}0.32{\mu}l/s$ over the inlet pressure range of $20{\sim}50$ kPa. The present flow-rate regulator having simple structure and lower compensation pressure level demonstrates potentials for use in integrated micropump systems.

The Performance Characteristics of Anti-Surge Devices for High Head Cooling Water Systems in 1,000 MW Thermal Power plants (고수두 1,000 MW 석탄화력발전소 냉각수계통 수격방지장치의 성능특성)

  • Kim, Keun-Pil;Yoo, Hoseon
    • Plant Journal
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    • v.15 no.4
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    • pp.36-42
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    • 2019
  • In recent, according to the tightening of environment regulation policy, the height of the site of the power plant is increased and the length of the cooling water pipe is increased. This has a serious impact on the stability of the plant. This study analyzes the transient phenomenon using LIQT 7.2, an unsteady state one-dimensional analysis software, to secure the stability of 1,000 MW high-capacity coal-fired power plant cooling water system with high head. To prevent water hammer, The effects on performance characteristics were predicted by individual and combination application. The surge pressure of the cooling water which occurs when the pump was stopped without installing the anti-surge devices was the largest at the pump outlet side. The most effective and simple way to reduce surge pressure in these cooling water systems is to combine a vacuum breaker with a hydraulic non-return valve, which is an essential device for pump protection.