• Title/Summary/Keyword: Transfer unit

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Study on the Design of Cam-type Transfer Unit using Conjugate Cam (복소캠을 이용한 캠 타입 이송장치의 설계)

  • 이택민;이동윤;양민양
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.844-847
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    • 2003
  • This thesis suggests design considerations and solutions for cam type transfer unit in which feed, lift, and clamp motions are occurred by cams. For fast transferring and avoiding cam breakage, each designed cam must satisfy the given specifications such like velocity, acceleration, jerk, pressure angle, ram thickness, and torque. To reduce absolute torque magnitude, conjugate cam is suggested. Conjugate cam eliminates the redundant pre-load by using complementary cam and follower to avoid jumping between them. The result from the prototype shows the reductions of the absolute torque value, and it indicates that conjugate cam could enhance the working speed of cam type transfer unit and extend of the life span of cam type transfer unit.

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Study on the Design of Cam-type Transfer Unit (대형 캠 타입 이송장치의 설계에 관한 연구)

  • 이택민;이동윤;양민양
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.1
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    • pp.31-39
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    • 2004
  • This paper presents design solutions for cam type transfer unit in which feeding, lifting, and clamping motions are generated by cams. In order to achieve faster transfer motion, each designed cam must satisfy the given specifications such as velocity, acceleration, jerk, pressure angle, cam thickness, and torque. To reduce absolute torque magnitude and torque variation, a conjugate cam and a torque reduction cam are used respectively. The conjugate cam eliminates the redundant pre-load by using complementary cam to avoid jumping between a cam and a follower. The torque reduction cam reduces the torque variation by applying opposite torque to a cam shaft. The experimental result shows the reductions of the absolute torque value and torque variation. The improvement of working speed and life span of cam type transfer unit can be expected.

An easy-to-use design procedure for multipass plate heat exchangers based on the performance plots (성능선도에 의한 다통로 판형열교환기의 간이설계법)

  • 유호선;이근휘;방보청
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.2
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    • pp.250-261
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    • 1999
  • Based on a set of performance plots relating the design variables to the imposed conditions, an easy-to-use and versatile design procedure for chevron-type multipass plate heat exchangers is developed. In order for the present procedure to cover multipass with unequal passes and non-unity ratio of heat capacity rate, each stream number of transfer unit is adopted as the basic design variable instead of the exchanger number of transfer unit. It is found that there exists a unique relation between the stream and exchanger number of transfer units regardless of the chevron angle and the plate length. In addition, for a given value of the pressure drop the heat transfer area per unit mass flow rate can be expressed in terms of the stream number of transfer unit only. These two relationships in the form of simple plots constitute the framework of design. The sample results in comparison with the available data indicate that the present procedure includes the previous ones as a subset, and that every design method is affected essentially by the selection of specific correlations for the heat transfer coefficient and the friction factor.

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Numerical Study for Heat Transfer Characteristics Varying Cross-Sectional Shape of a Tube (관 단면형상 변화에 따른 열전달 특성에 관한 수치해석적 연구)

  • Park, Hun-Chae;Choi, Hang-Seok;Kim, Seock-Joon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.7
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    • pp.560-566
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    • 2012
  • Numerical study has been carried out to investigate heat transfer and pressure drop characteristics for streamlined shape tubes. The flow and thermal fields are investigated with varying diameter ratio of the tube ranging from 0.4 to 2.5 and Reynolds number ranging from 10,000 to 30,000. The results show that heat transfer per unit fan power is maximum at $D_2/D_1=0.8$. Furthermore, the heat transfer per unit fan power of streamlined shape tubes was compared with circular tube. The heat transfer per unit fan power of streamlined shape tube was larger than that of circular tube.

Floated Wafer Motion Modeling of Clean Tube system

  • Shin, Dong-Hun;Yun, Chung-Yong;Jeong, Kyoo-Sik;Choi, Chul-Hwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1264-1268
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    • 2004
  • This paper presents a wafer motion modeling of the transfer unit and the control unit in the clean tube system, which was developed as a means for transferring the air-floated wafers inside the closed tube filled with the super clean airs. The motion in the transfer unit is modeled as a mass-spring-damper system where the recovering force by air jets issued from the perforated plate is modeled as a linear spring. The motion in the control unit is also modeled as another mass-spring-damper system, but in two dimensional systems. Experiments with a clean tube system built for 12-inch wafers show the validity of the presented force and motion models.

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A study on Removal of $NH_3$ Gas in a Towar using a Ralu-Pack 250YC as a Packing Material (Ralu-Pack 250YC를 충전한 충전탑에서 암모니아가스 제거에 관한 연구)

  • 김석택
    • Journal of Environmental Science International
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    • v.9 no.5
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    • pp.389-392
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    • 2000
  • In this study a packed tower was selected for the treatment apparatus of $NH_3$ gas produced in industry. Formerly latticework packing has been used in preventive facility of treatment of $NH_3$ gas. However recently metallic Ralu-Pack 250YC. structured packing is usually being used in petrochemical production plant. This study is for the application the packing to the $NH_3$ gas treatment in wet scrubbing process. In Air/water system hydraulic pressure drop dependent of specific liquid load and gas capacity factor was continuous and parallel from graph. The tower height can be determuined by the number of transfer unit and the height of transfer unit influenced on liquid distribution.

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Uncertainty and Transfer Anxiety of Pediatric Patients' Mothers upon Discharge from the Pediatric Intensive Care Unit (소아중환자실 퇴실 시 환아 어머니의 불확실성과 전동불안)

  • Song, Min-Kyung;Bang, Kyung-Sook
    • Korean Parent-Child Health Journal
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    • v.15 no.2
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    • pp.80-88
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    • 2012
  • Purpose: This study was done to investigate the level of uncertainty, transfer anxiety, and to identify the participant's characteristics those influence them by targeting the mothers of transferred patients from the pediatric Intensive Care Unit (PICU) to the general ward. Methods: This study was a descriptive correlational study. The participants were 94 mothers of children who had been scheduled to transfer from the PICU. Results: The item mean score for uncertainty was 2.16 (4 scale), transfer anxiety was 2.15 (4 scale). There were statistically significant positive correlation between uncertainty and transfer anxiety (r=.591). The level of uncertainty significantly differed according to education level (p=.035), duration of marriage (p=.043), and monthly income (p=.022). The level of transfer anxiety significantly differed according to religion (p=.044), duration of marriage (p=.043), and severity of illness at transfer (p=.047). Conclusion: In order to reduce the transfer anxiety and uncertainty of the mothers of patients, efficient communication with medical staff and clear informations are needed to reduce ambiguity. Also, standard protocol should be developed for improving communication among medical staffs.

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A Study on the Heat Transfer Characteristics of Heating Unit in DPH HVAC (수송용 DPH HVAC 히팅유니트장치의 열유동 시뮤레이션평가연구)

  • Roh, Hong-Koo;Lim, Kyung-Bin;Noh, Jong-Ho;Lee, Young-Ki
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.605-610
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    • 2008
  • The study aims to analyzed and identify the heat transfer characteristics of heating unit for room using 3-D numerical-analysis in order to design heating unit. The temperature comparison processes were done with various numerical conditions. In addition, the optimal conditions of heating unit design were proposed as inlet temperature, the inlet flow, heater power, and vessel size.

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Experimental study on the heat transfer characteristics of woofer speaker unit (우퍼 스피커 유닛의 열전달 특성에 대한 실험적 연구)

  • Kim, Hyung-Jin;Kim, Dae-Wan;Lee, Moo-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.5
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    • pp.2623-2627
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    • 2014
  • The objective of this study is to experimentally investigate the heat transfer characteristics of 200W woofer speaker unit with the input voice signals such as 500 Hz, 1000 Hz, 2000 Hz, and 3000 Hz. The temperature and heat transfer characteristics of the woofer speaker unit were evaluated with the input signals. As results. the temperature of the voice-coil for woofer speaker unit increased with a decrease of the input signals and the temperature differences between parts of the tested speaker unit increased with the decrease of the input voice signals. In addition, the voice-coil temperature for the input signal of 500 Hz showed 48.4 % lower than that of 3000 Hz during 18000 sec.

Analysis on the Thermal Performance of an Ammonia Unit Cooler (암모니아 유니트 쿨러의 열성능 해석)

  • 최재광;김무근;박병규
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.11
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    • pp.1125-1133
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    • 2001
  • Since the surface temperature of the evaporating tube in an ammonia unit cooled is lower than the dew point of atmosphere, the moisture in the atmosphere condenses and the frost grows on the tube. The frost of liquid film decreases the heat transfer rate. The reliable analysis of the heat transfer is required for the prediction of the optimal design of the ammonia unit cooler. For the specific commercial model, the performance was numerical1y estimated for the variation of operating condition and geometric configuration. It is found that there exists an optimum range for the parameters such as mass flow rate of air and refrigerant, humidity, refrigerant quality, fin pitch, the number of step, the number of rows and the pattern of refrigerant path.

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