• Title/Summary/Keyword: Air table

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Removal of PVC from Granular Plastic Mixture by Using Air Table (Air Table을 이용한 입상플라스틱 혼합물로부터 PVC의 건식분리)

  • ;Hiroki Yotsumoto
    • Resources Recycling
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    • v.10 no.6
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    • pp.35-42
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    • 2001
  • A study was conducted in order to remove Poly vinyl chloride (PVC) from granular plastic mixture by using Air Table. The motion of plastic particle on Air Table was investigated, and separation test on the plastic mixture with the mixing ratio of PVC 10% and PE 90% was conducted. At the optimum condition obtained from this study, that is frequency of 9.2Hz, air velocity of 1.05 m/sec, End-slope of $7.5 ^{\circ}$, Side-slope of $1^{\circ}$, Feeding speed of 450 g/min, etc., we could separate the PE-PVC mixture to PE (99.96% grade and 98.9% yield) and PVC (88.7% grade and 99.6% yield).

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Active Control of Air-Spring Vibration Isolator (공기스프링 방진대의 능동제어)

  • 송진호;김규용;박영필
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.7
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    • pp.1605-1617
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    • 1994
  • Air-spring is widely used in vibration isolation to reduce the table vibration. When a disturbance is applied to a table, however, it starts virbrating with a low frequency, but has a large displacement due to the reacting force of air-spring. In this study, to solve the table vibration problem, an active vibration control device based on state feedback control using air-spring and proportional control valves was designed. This device can suppress the displacement of the isolation table within allowable range, even any kind of disturbances are applied to the table. Firstly, theoretical analysis of an air-spring isolator was done. Secondly, characteristics of the isolator was investigated via computer simulation and experiment. Finally, active control of air-spring isolator was tested using optimal(LQG) and fuzzy control algorithms was performed to show the effectiveness of the control schems.

Dry Separation of PVC Film from Plastic Film Mixture by Using Air Table

  • Song, Young-Jun;Hiroki Yotsumoto;Lee, Gye-Seung
    • Resources Recycling
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    • v.11 no.1
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    • pp.37-42
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    • 2002
  • This study was conducted in order to remove Poly vinyl chloride(PVC) from the waste plastic film mixture. The fittings of Air Table was modified to increase the separation efficiency of PVC and PE(poly ethylene). PE and PVC was successfully separated from PVC-PE film mixture with the yield of PE 90% or more and with his grade of 99% or more, using the improved Air Table. The details of the separation condition and results will be discussed in this paper. Dry separation, Waste plastic film, PVC, Air Table. The details of the separation condition and results will be discussed in this paper.

Design and Evaluation of a Rotation Table using Air Bearings for Electron Beam Mastering (전자빔 마스터링을 위한 공기베어링 응용 고진공 회전테이블의 설계 및 진공특성 평가)

  • Khim, Gyung-Ho;Song, Chang-Kyu;Park, Chun-Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.12
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    • pp.132-138
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    • 2008
  • Recently, mastering processes for high density optical disc such as Blu-ray disc rely on electron beams, which are operable in only vacuum. In the mastering process, one of the most important tasks is to design precision stages for providing precise positioning of the works with respect to the source in a high vacuum environment. In this paper, we have developed a precision rotation table usable in the electron beam mastering. The rotation table adopted air bearings for a high positioning repeatability and velocity stability. The air leakage from the air bearings has been minimized by employing the differential exhaust scheme using three steps of air drain. The design parameters such as diameters of exhaust lines, seal lengths, and pumping speeds were decided according to the optimization method using genetic algorithm. The performance on the vacuum level of the rotation table was evaluated experimentally and theoretically. The results indicate that a vacuum level of $10^{-4}$ Pa is achieved with operation of air bearings in a vacuum chamber, which is sufficient for the electron beam mastering.

Active Control of Isolation Table Using $H_\infty$ Control ($H_\infty$ 제어를 이용한 방진대의 능동제어)

  • Kim, Kyu-Young;Yang, Hyun-seok;Park, Young-Pil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.10
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    • pp.3079-3094
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    • 1996
  • Recently, the high-precision vibration attenuation technology becomes the essence fo the seccessful development of high-integrated and ultra-precision industries, and is expected to continue playing a key role in the enhancement of manufacturing technology. Vibration isolation system using an air-spring is widely employed owing to its excellent isolation characteristics in a wide frequency range. It has, however, some drawbacks such as low-stiffness and low-damping features and can be easily excited by exogenous disturbances, and then vibration of table is remained for a long time. Consequently, the need for active vibration control for an air-spring vibration isolation system becomes inevitable. Furthermore, for an air-spring isolation table to be successfully employed in a variety of manufacturing sites, it should have a guaranteed robust performance not only to exogenous disturbances but also to uncertainties due to various equipments which might be put on the table. In this study, an active vibration suppression control system using H.inf. theory is designed and experiments are performed to verify its robust performance. An air-spring vibration isolation table with voice-coil-motors as its actuators is designed and built. The table is modeled as 3 degree-of-freedom system. An active control system is designed based on $H_\infty$control theory using frequency-shaped weighting functions. Analysis on its performance and frequency responce properties are done through numerical simulations. Robust characteristics of$H_\infty$ control on disturbances and model uncertainties are experimentally verified through (i) the transient response to the impact excitation of the table, (ii) the steady-state response to the harmonic excitation, and (iii) the response to the mass change of the table itself. An LQG controller is also designed and its performance is compared with the $H_\infty$ controller.

Active Control of Vibration Isolation Table Using Air-spring (공기스프링을 이용한 방진테이블의 능동 제어)

  • An, Chae-Hun;Yim, Kwang-Hyeok;Jin, Kyong-Bok;Rim, Kyung-Hwa
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.7 s.124
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    • pp.565-571
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    • 2007
  • In the process of accurate manufacture and measurement, it is necessarily required to isolate external or internal vibration due to external disturbance and internal actuators. The higher vibration isolation system gets damping around resonance, the better it is generally. This paper analyzes the performance of an existing passive air-spring for vibration isolation table by using experiment and simulation. Optimal design for a passive air spring can be obtained by tuning the size of the orifice. Also design for an active isolation system is carried out by applying PID controller and considering non-linearity of pneumatic characteristics with help of look-up table. We have developed the active vibration isolation table with the better isolation performance.

Active Control of Vibration Isolation Table Using Air-spring (공기스프링을 이용한 방진 테이블의 능동 제어)

  • An, Chae-Hun;Yim, Kwang-Hyeok;Kwon, Hyeok-Jin;Jung, Jin-Hoon;Bae, Yoon-Hwa;Jin, Kyong-Bok;Rim, Kyung-Hwa
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.831-836
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    • 2006
  • In the process of accurate manufacture and measurement, it is necessarily required to isolate external or internal vibration due to external disturbance and internal actuators. The higher vibration isolation system gets damping around resonance, the better it is generally. This paper analyzes the performance of an existing passive air-spring for vibration isolation table by using experiment and simulation. Optimal design for a passive air spring can be obtained by tuning the size of the orifice. Also design for an active isolation system is carried out by applying PID controller and considering non-linearity of pneumatic characteristics with help of look-up table. We have developed the active vibration isolation table with the better isolation performance.

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Development of precision vibration isolation table and study of dynamic characteristics with experiment (정밀 제진대 개발 및 동특성에 관한 실험적 연구)

  • 김인수;김종연;한문성;김영중
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11a
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    • pp.329-334
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    • 2001
  • Recently, the high precision technology can not be developed continuously if we don't have anti vibration technology. Vibration isolation technology using an air spring and laminated robber bearing is widely used because it has excellent vibration isolation characteristics. We developed high precision vibration table with two good element(air spring and LRB) for semiconductor factory. Air Spring is used for isolating the vertical vibration and LRB is used for isolating the horizontal Vibration. As a result, It has D-Class degree in BBR-Criteria. In this paper, we talk about orifice characteristics in the self-damped air spring and design flow of the laminated robber bearing. The orifice characteristics is delicate shade of length and diameter. When we do experimentation to find orifice characteristics, length is fixed and diameter is changed. The orifice diameter is the wider and the air spring stiffness is the softer.

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Study on the Outdoor Conditions for Air Conditioning Design in Korea (한국의 공기조화설계용 외기조건)

  • 김효경
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.1 no.1
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    • pp.3-11
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    • 1972
  • The outdoor design conditions for the locality are the basic problem in the design of air conditioning system. The ideal solution to the basic problem is to design a building that has a capacity at maximum output just equal to the load which develops the most severe conditions for the locality occur, but in most cases, economics interferes the attainment of the ideal. Studies of weather records show that the most severe conditions do not repeat themselves every year. The weather conditions of principal cities such as Seoul, Inchon, Suwon, Taegu, Chonju, Ulsan, Kwangju, Pusan and Mokpo in Korea have been analyzed to determine the probability of occurrence of certain temperatures according to recent 10 years $(1960\∼1969)$ weather records. The outdoor conditions for winter air conditioning design are shown on Table 2. The outdoor conditions for summer air condioning design are shown on Table 7. Heating degree days are shown on Table 10 and 11.

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