• Title/Summary/Keyword: Vacuum Sealing

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Leakage-free Rotating Seal Systems with Magnetic Nanofluids and Magnetic Composite Fluids Designed for Various Applications

  • Borbath, Tunde;Bica, Doina;Potencz, Iosif;Borbath, Istvan;Boros, Tibor;Vekas, Ladislau
    • International Journal of Fluid Machinery and Systems
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    • v.4 no.1
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    • pp.67-75
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    • 2011
  • Recent results are presented concerning the development of magnetofluidic leakage-free rotating seals for vacuum and high pressure gases, evidencing significant advantages compared to mechanical seals. The micro-pilot scale production of various types of magnetizable sealing fluids is shortly reviewed, in particular the main steps of the chemical synthesis of magnetic nanofluids and magnetic composite fluids with light hydrocarbon, mineral oil and synthetic oil carrier liquids. Design concepts and some constructive details of the magnetofluidic seals are discussed in order to obtain high sealing capacity. Different types of magnetofluidic sealing systems and applications are reviewed. Testing procedures and equipment are presented, as well as the sealing capabilities of different types of magnetizable fluids.

Development of Tubeless-Packaged Field Emission Display (Tubeless Packaging된 Field Emission Display의 개발)

  • Ju, Byeong-Gwon;Lee, Deok-Jung;Lee, Yun-Hui;O, Myeong-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.4
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    • pp.275-280
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    • 1999
  • The glass-to-glass electrostatic bonding process in vacuum environment was developed and the tubeless-packaged FED was fabricated based on the bonding process. The fabricated tubeless-packaged FED showed stable field emission characteristics and potential applicability to the FED tubeless packaging and vacuum in-line sealing.

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Electrical and Optical Characterization of the Vacuum In-Line Sealed PDP Panel

  • Kwon, Sang-Jik;Kim, Jee-Hoon;Kim, Tae-Ho;Shon, Byeong-Kyoo;Yang, Hwi-Chan
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.832-835
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    • 2003
  • By using vacuum in-line driving and photoluminescence measuring method, we have observed the electrical and optical characteristics of the vacuum in-line sealing technology and analyzed the effect of the base vacuum level before filling the plasma gas. In the case of base vacuum level of $1{\times}10^{-3}$torr, the firing voltage of a 2-inch diagonal PDP panel was ranged from 310 to 345V depending on the plasma gas pressure of 200 to 300torr and luminous efficiency was ranged from 0.0227 to 0.0367 lm/W depending on the input voltage level of 330 to 225V. While, in the case of $1{\times}10^{-6}$, the characteristics were significantly improved. As a results, the firing voltage was ranged from 295 to 318V and luminous efficiency was from 0.0278 to 0.0451 lm/W.

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Changes of Chemical and Microbiological Quality of Home-delivered meals for elderly as affected by Packaging methods and Storage conditions 2 (노인을 위한 가정배달급식의 포장방법 및 저장조건에 따른 이화학적ㆍ미생물학적 품질 변화 2)

  • 김혜영;류시현
    • Korean journal of food and cookery science
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    • v.19 no.2
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    • pp.241-253
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    • 2003
  • Changes in chemical, microbiological quality of pan fried oak mushroom and meat, soy sauce glazed hair tail and roasted dodok in wrap packaging, top sealing, vacuum packaging were evaluated during storage 25$^{\circ}C$, 4$^{\circ}C$, -18$^{\circ}C$ for 5 days. The results were as follows: 1) The cases of chilled and frozen storage, there were small increases in the pH from the first day, with no differences between the different packaging methods, with the exception of the vacuum packaging, which was lower. The pH and Aw of the roasted dodok were lower than those of the other foods. The Aw for all three foods at room temperature significantly decreased in the wrap packaging and top sealing on day one, but the rate of reduction was lower when in chilled storage. The VBN increased with increasing length of storage, and temperatures, but the rate of increase was lower in the top sealing and vacuum packaging. The VBN of roasted dodok was considerably lower than with the other foods. The POV increased significantly on the first day or room temperature storage and the rate or increase was low in chilled End frozen storages, and in the vacuum packaging. 2) SPC of the roasted dodok at room temperature increased significantly within five days of storage. but was inhibited within five days in the vacuum packaging with chilled storage. The SPC of the soy sauce glazed hair tail was low in the top sealing and vacuum packaging when in chilled storage. The coliform of the pan fried oak mushroom and meat. on the fifth day of room temperature storage, was close to hazardous conditions for the wrap packaging. From the third day of chilled storage, few coliform were detected in the pan fried oak mushroom and meat, or the soy sauce glazed hair tail, but not in the vacuum packaging, within five days, for all three foods in frozen storage. The S. spp. had exceeded the standard in the wrap packaging and top sealing with the pan fried oak mushroom and meat on the third day at room temperature, but was not detected in the vacuum packaging within five days, and exceeded the standard in the wrap packaging on the fifth day of chilled storage. S. spp. was not detected in the soy sauce glazed hair tail within five days at all storage temperatures. S. spp. was not detected in the roasted dodok within five days of chilled and frozen storage, but was detected from the third day in the wrap packaging. and the fifth in the top sealing, at room temperature, which exceeded the standard. Sal. spp., V parahaemolyticus, E. coli O157:H7, L. monocytogenes were not detected. 3) The Aw was found to be influenced by storage temperature, period and packaging method, while the VBN was significantly influenced by the storage temperature and period. Regarding the SPC, the pan fried oak mushroom and meat was affected by the storage temperature and period, while the soy sauce glazed hair tail was influenced by the packaging method and storage period. The roasted dodok's microbiological quality was influenced by the method of packaging. The chemical, microbiological quality of home-delivered meals were preserved to be five days in the vacuum packaging, at. chilled and frozen storage.

Development of a Magnetic Seal and the Leak Test (마그네틱씰 개발 및 기밀 평가 시험)

  • Kim, Ock-Hyun;Lee, Min-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.2
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    • pp.79-83
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    • 2011
  • Magnetic seal uses a magnetic fluid to seal a gap between a rotating shaft and housing. It is distinguished from other kinds of seals from the fact that solid contact does not occur in the seal. This implies that it is free from solid rubbing thus dustless and provides a clean circumstance. That is the reason why the magnetic seal is used exclusively for most of vacuum chambers in semiconductor process where dustless clean circumstance is critical. A magnetic seal has been developed of which design parameters are determined based on published data, and an air pressure test has been done to examine its sealing capability. Effects of some design parameters have been studied through FEM analysis. The results show some notable aspects of design parameters and provide suggestions for developing the seals. Regarding the sealing capacity of the magnetic seal the factor to match the theoretical value with the actual one was found to be 0.4~0.7, which means still there is some discrepancy between theory and actual.

Effect of Beating Time and Fines Content on the Drainage Properties of BKP (고해처리와 미세분 함량에 따른 BKP의 탈수특성변화)

  • 성용주;이학래
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.31 no.1
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    • pp.52-60
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    • 1999
  • Drainage rate in wet-end, which has significant influences on the production capacity, product quality and process economics in papermaking, becomes an important factor in the modern high speed papermaking processes owing to increased level of fines contained in today's pulp materials and increased papermaking system closure. A study was carred out to investigate the influence of beating and fines content on natural and vacuum dewatering using a vacuum drainage tester. Increase in beating and accumulation of fines in the stock decreased natural dewatering, Vacuum dewatering effect, however, increased substantially as beating and fines content were increased. But this increase in vacuum dewatering decreased again when a stock is severely beaten or fines content is greater than 35%. Above this level of fines content, mobile fines migrates to the interstices of the forming web to cause sealing or plugging which restrict fluid movement through the web.

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Discharge characteristics of MgO-PDP manufactured by using "all-in-vacuum" process

  • Yano, T.;Uchida, G.;Uchida, K.;Awaji, N.;Shinoda, T.;Kajiyama, H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.28-30
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    • 2009
  • PDP panels with MgO protective layer are manufactured by using the "all-in-vacuum" process we have established [1]. This is the process aiming to keep the MgO surface as clean as possible after the evaporation. The panels are evaluated in term of discharge voltage, aging time, luminance, luminous efficacy, discharge time-lag. It is confirmed that the "all-in-vacuum" process particularly improves the aging time, discharge voltage and the discharge time-lag.

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Manufacturing and characterization of ECR-PECVD system (ECR-PECVD 장치의 제작과 특성)

  • 손영호;정우철;정재인;박노길;황도원;김인수;배인호
    • Journal of the Korean Vacuum Society
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    • v.9 no.1
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    • pp.7-15
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    • 2000
  • An ECR-PECVD system with the characteristics of high ionization rat다 ability of plasma processing in a wide pressure range and deposition at low temperature was manufactured and characterized for the deposition of thin films. The system consists of a vacuum chamber, sample stage, vacuum gauge, vacuum pump, gas injection part, vacuum sealing valve, ECR source and a control part. The control of system is carried out by the microprocessor and the ROM program. We have investigated the vacuum characteristics of ECR-PECVD system, and also have diagnosed the characteristics of ECR microwave plasma by using the Langmuir probe. From the data of system and plasma characterization, we could confirmed the stability of pressure in the vacuum chamber according to the variation of gas flow rate and the effect of ion bombardment by the negative DC self bias voltage. The plasma density was increased with the increase of gas flow rate and ECR power. On the other hand, it was decreased with the increase of horizontal radius and distance between ECR source and probe. The calculated plasma densities were in the range of 49.7\times10^{11}\sim3.7\times10^{12}\textrm{cm}^{-3}$. It is also expected that we can estimate the thickness uniformity of film fabricated by the ECR-PECVD system from the distribution of the plasma density.

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Influence of Ambient Gases on Field Emission Performance in the Frit-sealing Process of Mo-tip Field Emission Display (몰리브덴 팁 전계 방출 표시 소자의 프릿 실링에 있어서 분위기 기체가 전계 방출 성능에 미치는 영향)

  • Ju, Byeong-Kwon;Kim, Hoon;Jung, Jae-Hoon;Kim, Bong-Chul;Jung, Sung-Jae;Lee, Nam-Yang;Lee, Yun-HI;Oh, Myung-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.7
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    • pp.525-529
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    • 1999
  • The influence of ambient gases on field emission performance of Mo-field emitter array(FEA) in the frit-sealing step of field emission display(FED) packaging process was investigated. Mo-tip FEA was mounted on the glass substrate having a surrounded frit(Ferro FX11-137) and fired at $415^{\circ}C$ in the ambient gases of air, $N_2$ and Ar. The Ar gas was proved to be most proper ambient among the used gases through evaluating the turn-on voltage and field emission current of the fired Mo-tip FEA devices. It was confirmed that the Mo surface fired in Ar ambient was less oxidized when compared with another ones annealed in air and Ar ambient by the AFM, XPS, AES and SIMS analysis. Finally, the 3.5 inch-sized Mo-tip FED, which was packaged using frit-sealing process in the Ar ambient, was proposed.

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Vacuum packaging of MEMS (Microelectromechanical System) devices using LTCC (Low Temperature Cofired Ceramic) technology (LTCC 기술을 이용한 MEMS 소자 진공 패키징)

  • 전종인;최혜정;김광성;이영범;김무영;임채임;황건탁;문제도;최원재
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.11a
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    • pp.195-198
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    • 2002
  • 현재의 광통신, 이동통신 및 디지털 시대에서는 보다 소형화되고, 대용량의 데이터 저장 및 다기능 소자에 대한 요구가 많아지고 있다. 이러한 전자 산업 환경에서 MEMS 소자는 여러 요구조건을 만족시킬 수 있는 특징을 갖추고 있으며 실제 소자의 제작에 있어서 MEMS 소자를 이용하여 여러 물리 및 화학 센서 및 Actuator 제작에 응용이 되어지고 있고 Optical switch, Gyroscope, 적외선 어레이 센서, 가속도 센서, 위치 센서 등 여러 분야에서 실용화가 진행되어지고 있다. MEMS 구조물의 packaging 방법에 있어서는 내부 MEMS 소자의 동작을 위한 외부 환경으로부터의 보호를 위하여 Hermetic sealing에 대한 요구를 만족시켜야 한다. 본 발표에서는 이와 같은 MEMS device의 진공 패키지를 구현함에 있어서 기판 내부에 수동소자를 실장할 수 있는 LTCC 기술을 이용하여 진공 패키징하는 방법에 대하여 소개한다. 본 기술을 이용하는 경우 기존의 Hermetic sealing 이외에 향후 적층 기판 내부에 수동소자를 내장시켜 배선 길이 및 노이즈 성분을 감소시켜 더욱 전기적 성능을 향상시킬 수 있는 장점이 있게된다. 본 논문에서는 LTCC 기판을 이용하여 패키징 시킨 후, 내부 진공도에 영향을 줄 수 있는 계면들에서의 시간에 따른 진공도 변화의 특성치를 측정하여 LTCC 기판의 Hermetic sealing 특성에 관하여 조사하였다.

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