• 한국가스학회:학술대회논문집
• /
• 1998.09a
• /
• pp.89-94
• /
• 1998

• 한국가스학회:학술대회논문집
• /
• 1999.09a
• /
• pp.34-40
• /
• 1999

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.4
• /
• pp.180-184
• /
• 2012

3-way ball valves have been mostly used for high temperature/high pressure valves using in petrochemical carriers and oil tankers, which requires high quality products with confidentiality and durability. As a larger disaster may be generated by leakage of oil or gas from valves, thus the present research applied a numerical analysis method with thermal-structural coupled field analysis and the performance test. The Max stress by parts was confirmed through thermal-structural coupled field analysis and develop the 3-way ball valve design, which is safe on operating condition. And its performance was verified by carrying out pressure test, leakage test and durability test for the manufactured 3-way ball valves with satisfying it's regulations.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.12
• /
• pp.3553-3558
• /
• 2009

This study has been conducted to improve coolant flow pattern in the gasoline engine. Flow field has been calculated for the coolant passage mainly around the exhaust ports and valves. For the original model, a flow stagnant region has existed between exhaust valves of the second cylinder. To improve coolant flow characteristics, coolant passage area has been re-modeled and optimized. Furthermore, for the improved coolant core model, coolant passage under the exhaust manifold has been added to reduce exhaust-gas temperature. It was found that the flow through a gasket plays a critical role for the flow in the cylinder head and around exhaust valves. Finally, coolant flow around exhaust valves and in the cylinder head has been improved in terms of flow rate distribution.

• Journal of the Korean Ceramic Society
• /
• v.42 no.11 s.282
• /
• pp.758-762
• /
• 2005

Gas valve for domestic use is used for flow control of LPG (Liquefied Petroleum Gas) or LNG (Liquefied Natural Gas) of which pressure is about $200\;mmH_{2}O(\fallingdotseq0.0196\;[bar])$. Currently, two kinds of valves such as rotary type and button type are widely used in many applications. But, these valves have some problems that they are not controllable and reliable. Piezo actuation combined with modem microelectronics provides a reliable, quiet, low energy, infinitely adjustable gas valve. In this paper, gas valve using piezo actuator which are bimorph and a circle type was studied. Also, Prototype for gas valve was manufactured and characteristics of the prototype gas valve were analyzed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.1083-1084
• /
• 2010

• Journal of Korean Society of Water and Wastewater
• /
• v.37 no.4
• /
• pp.215-229
• /
• 2023

In this study, non-destructive technologies that can be applied to evaluate the integrity of valve materials, safety against internal pressure caused by corrosion, and the blocking function of large-diameter water valves during operation without requiring specimen collection or manpower entering the inside of the valve were tested to assess the reliability of the technologies and their suitability for field application. The results showed that the condition of the graphite structure inside the valve body can be evaluated directly through the optical microscope in the field without specimen collection for large-diameter water butterfly valves, and the depth of corrosion inside the valve body can be determined by array ultrasound and the tensile strength can be measured by instrumented indentation test. The reliability of each of these non-destructive techniques is high, and they can be widely used to evaluate the condition of steel or cast iron pipes that are significantly smaller in thickness than valves. Evaluation of blocking function of the valves with mixed gas showed that it can be detected even when a very low flow rate of mixed gas passes through the disk along with the water flow. Finally, as a result of evaluating the field applicability of non-destructive technologies for three old butterfly valves installed in the US industrial water pipeline, it was found that it is possible to check the material and determine the suitability of large-diameter water valves without taking samples, and to determine the corrosion state and mechanical strength. In addition, it was possible to evaluate safety through the measurement results, and it is judged that the evaluation of the blocking function using mixed gas will help strengthen preventive response in the event of an accident.

• Journal of Mechanical Science and Technology
• /
• v.19 no.12
• /
• pp.2197-2204
• /
• 2005

The combination of Gas chromatography (GC) for separation and Flame Ionization Detection (FID) for detection and identification of the components of a mixture of compounds is a fast and strongly proved method of analytic chemistry. The objective of this research was to design a combined High-speed miniature screening Gas chromatograph along with a Flame Ionization Detector for quick, quantitative and qualitative analysis of gas components. This combined GC-FID system is suitable to detect the volatile and semi-volatile hydrocarbons present in a gas mixture. The construction made it less expensive, easy to use and movable. The complete gas path was developed. On/off valves, temperature and flow sensors and their interface electronics were used for controlling purpose. A Microcontroller was programmed to measure the temperature and gas flow using the sensors and to control and regulate them using the electronics and valves. A pocket PC with its touch screen served as a user interface for the system. Software was developed for the pocket PC, which makes the communication possible with the Microcontroller. The system parameters can be indicated in the Pocket PC as simple text and also the analysis result can be displayed.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.14 no.3
• /
• pp.85-93
• /
• 2006

The present study has been conducted to simulate dynamics of a gas engine-driven heat pump (GHP) for the design of control algorithm. The dynamic model of a GHP was based on conservation laws of mass and energy. For the control of refrigerant pressures, actuators such as an engine throttle valve, outdoor fans, coolant three-way valves and liquid injection valves were controlled by P or PI algorithm. The simulation results were found to be realistic enough to be applied for the control algorithm design. The model could be applied to build a virtual real-time GHP system so that it interfaces with a real controller for the purpose of developing control algorithm.

• Journal of Mechanical Science and Technology
• /
• v.20 no.2
• /
• pp.278-285
• /
• 2006

The present study has been conducted to simulate dynamics of a gas engine-driven heat pump (GHP) for design of control algorithm. The dynamics modeling of a GHP was based on conservation laws of mass and energy. For automatic control of refrigerant pressures, actuators such as engine speed, outdoor fans, coolant three-way valves and liquid injection valves were PI or P controlled. The simulation results were found to be realistic enough to apply for control algorithm design. The model can be applied to build a virtual real-time GHP system so that it interfaces with a real controller in purpose of prototyping control algorithm.