• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.962-966
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• 2004

Suction transfer system with air suctioning is widely used and continuously developed in production automation. Air suctioning has some drawbacks in use. To generate vacuum in the suction cup with air suctioning, complex of mechanical component like as air compressor, air tube, air value is need, and it needs continuous air supply. And if the failure of the suction in a cup in the multi-suction cup system which is generally used occurs then the suctions of all of the cup will be fail. To overcome these drawbacks, new suction mechanism which uses permanent magnet for the movement of the suction cup is proposed. The proposed mechanism activates each suction cup separately, so the air leakage of a cup is not critical. The proposed suction system wasdesigned and fabricated in real world. With some experiments, the usability and performance of the suction mechanism was proved. The strong points of the proposed suction mechanism are simple structure, high energy efficiency, and discrete energy supply.

• 대한기계학회논문집A
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• 제29권12권
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• pp.1645-1652
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• 2005

Pick-and-place systems using suction cups have been being widely used and continuously developed in production automation. There are, however, some drawbacks in constructing such systems. One of them is that it generates high level noise due to air compressors. And the system must have complex constitutions of mechanical component such as air compressors, air tubes, air valves, etc. Moreover, it needs continuous air supply to maintain vacuum in suction cups. If there is a failure in any suction cup, the total suction system may fail owing to air leakage. To overcome these drawbacks, we propose PMS (Permanent Magnet Suction) mechanism which has permanent magnets for vacuuming suction cups with no air compressor. The basic concept of PMS mechanism is to rotate permanent magnets with fixed angle. Simple rotation of permanent magnets changes the direction of the magnetic force applied at the suction cups. Since each suction cup has no direct connection with any of the others, the air leakage at one suction cup is not critical. The proposed suction mechanism was designed and fabricated. With some experiments, the feasibility and performance of the PMS mechanism was shown. The strong points of the PMS mechanism are in its simple structure, generating low noise, high energy efficiency, and no need of continuous energy supply.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.303-306
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• 2002

Liquid atomization by means of a spinning cup is widely used as a device for combustion, in cooling and spray drying. In this study, the blowing type rotary atomizer was experimental carried out the investigations on the characteristics of the blowing type rotary atomizer which is an air flow energy of blower instead of an electric motor most commonly used to a driven energy. The analysis on the rotary cup speed, air velocity with the blower conditions was performed and also the drop size was measured using LDPA. It was tried to analyzed on air-nozzle size and liquid flowrate as the result. It was found that the increase of the relative velocity between liquid and air improve significantly atomization liquid, and decrease of the liquid flowrate improved the maximum drop size though the mean drop size is really the same.

• 설비공학논문집
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• 제21권7호
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• pp.394-401
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• 2009

A manipulator is operated for the motion of mechanical hands or arms. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to viscous effect (the Reynolds number), the aspect ratio of the liquid inside the cup and the acceleration ratio (the Froude number). Through this study, the height of the free surface rise in a cup has been predicted and the detailed velocities in the liquid have been examined. Generally, the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. However, the influence of the aspect ratio on the maximum rise of the free surface is not negligible in the range of 10 < Re < 100.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 1999년도 춘계학술대회 논문집
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• pp.171-173
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• 1999

• 대한기계학회논문집B
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• 제38권8호
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• pp.671-676
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• 2014

볼텍스 컵은 실린콘 웨이프 제조공정과 같이 민갑한 물체을 이송시키는 방법으로 제안되었다. 볼테스 컵의 상부에 위치한 노즐을 통해 공기를 공급하면 내부 실린더에서 큰 선회유동이 생성된다. 공기는 볼텍스 컵과 바닥면 사이의 틈새로 빠져나가면서 흡입압력을 생성시키고 물체를 들어 올릴 수 있게 된다. 본 논문에서는 볼텍스 컵에 관한 3차원 유동 해석을 통해 실험 결과와 해석 결과를 비교하여 해석의 신뢰성을 확인하였다. 그리고 볼텍스 컵의 길이 변화와 형상 변화를 주어 해석을 통해 흡입 압력 생성에 영향을 미치는 정도를 분석하였고, 볼텍스 컵 형상의 최적 조건을 제시하였다.

• 한국분무공학회지
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• 제6권4호
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• pp.14-21
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• 2001

Rotary atomizer is widely used in practical application ranging from combustion, cooling, spray drying, agriculture, chemical system. Rotary cup atomizer has some advantages such as extreme versatility and liquid atomization successfully varying widely in viscosity. In rotary atomization, the feed liquid is centrifugally accelerated to high velocity and the liquid extends over the rotating surface as a thin film before being discharged into an atmosphere. The degree of rotary atomization depends upon peripheral speed, feed rate, liquid properties and atomizer design. An important asset is that thickness and uniformity of the liquid sheet can readily be controlled by regulating the liquid flow rate and the rotational speed. LDPA(Laser Diffraction Particle Analyser) and image aquisition system are used to measure drop size distribution and spray pattern. The atomization characteristics of the rotary cup atomizer is investigated experimentally by varing the liquid feed rate, rotary cup speed and air velocity for atomization. As a results, the effect of air velocity on the atomization characteristics such as drop size and spray uniformity is considerably greater than variation of those with liquid feed rate.

• 한국항공운항학회지
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• 제20권1호
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• pp.66-75
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• 2012

The purpose of this study is to analyze the effect of intervention variables which may affect the air travel demand for Jeju domestic flights and to anticipate the air travel demand for Jeju domestic flights. The air travel demand forecasts for Jeju domestic flights are conducted through ARIMA-Intervention Model selecting five intervention variables such as 2002 World Cup games, SARS, novel swine-origin influenza A, Yeonpyeongdo bombardment and Japan big earthquake. The result revealed that the risk factor such as the threat of war that is a negative intervention incident and occurred in Korea has the negative impact on the air travel demand due to the response of risk aversion by users. However, when local natural disasters (earthquakes, etc) occurring in neighboring courtiers and global outbreak of an epidemic gave the negligible impact to Korea, negative intervention incident would have a positive impact on air travel demand as a response to find alternative due to rational expectation of air travel customers. Also we realize that a mega-event such as the 2002 Korea-Japan World Cup games reduced the air travel demand in a short-term period unlike the perception in which it will increase the air travel demand and travel demands in the corresponding area.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1220-1225
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• 2009

A manipulator is operated for the motion of mechanical hands or arms. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to viscous effect (the Reynolds number), aspect ratio of the liquid inside the cup and the acceleration ratio (the Froude number). Through this study, the height of the free surface rise in a cup has been predicted and the detailed velocities in the liquid have been examined. Generally, the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. However, the influence of the aspect ratio on the maximum rise of the free surface is not negligible in the range of 10 < Re < 100.

• Journal of Biosystems Engineering
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• 제32권6호
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• pp.448-454
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• 2007

This study was conducted to develop a 100 kPa soil tensiometer mainly consisted of a porous ceramic cup, water-holding tube, and a digital vacuum gauge, through theoretical design analysis and experimental performance evaluation. Major findings were as follows. 1. Theoretical analysis showed that air entry value of a porous media decreased as the maximum effective size of the pore increased, and the maximum diameter of the pores was $2.9\;{\mu}m$ for measuring up a 100 kPa of soil-water tension. 2. Property analysis of tensiometer porous cups supplied in Korean domestic market indicated that main components were $SiO_2$ and $Al_2O_3$ with a porosity range of $33.8{\sim}49.3%$. 3. The porous cup selected through sample fabrication and air-permeability tests showed weight ratios of 87% and 11% for $Al_2O_3$ and $SiO_2$. The analysis of SEM (scanning electron microscope) images showed that the sample was sintered at temperatures of about $1150^{\circ}C$, which consisted of pores with sizes of up to 25% of those for commercial porous cups. 4. The prototype soil tensiometer was fabricated using the developed porous cup and a digital vacuum gauge that could measure water tension with a pressure of 85 kPa in air tests. 5. In-soil tests of the prototype conducted during a period of 25-day drying showed that soil-water tension values measured with the prototype and commercial units were not significantly different, and soil-water characteristic curves could be established for different soils, confirming accuracy and stability of the prototype.