• Journal of Biosystems Engineering
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• 제20권3호
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• pp.217-225
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• 1995

This study was conducted to find design factors of spraying device of the boom sprayer for low volume application. Four types of nozzles(standard flat nozzle, drift guard nozzle, even flat nozzle, and hollow cone nozzle) were used for the spray characteristic experiment. Spray patterns of the nozzles were distinguished by the nozzle type, spray distance, and spray direction. The flow rate was proportional to the square root of spray pressure in all nozzles. Increased nozzle height improved spray distribution at reduced pressures and/or increased spacing. Distribution tended to improve as pressure increased within the range of pressures used for fan nozzles.

• Journal of Biosystems Engineering
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• 제20권4호
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• pp.313-322
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• 1995

This study was conducted to find the design factors of spraying device of the boom sprayer for low volume application. Specific objectives of this study were 1) to select proper nozzles for broadcast spraying and row crop spraying by the nozzle spray characterisic experiment, and 2) to investigate the coverage characteristic of rice plant at the row crop spraying. The results of this study are summarized as follows. (1) From the tested results on the droplet diameter spectrum and spray pattern the standard flat-fan nozzle and drift guard nozzle were judged as appropriate for the broadcasting. Even flat-fan nozzle showed similar span values to standard flat-fan nozzles and drift guard nozzle : however, the nozzles were found to be inappropriate for broadcasting because of their spray pattern. Hollow cone nozzle showed relatively small span values and uniform spray pattern. (2) For the upper and lower sides of the rice plants, coverage rates of even flat-fan nozzles and hollow cone nozzles were maximum at the second row, but decreased rapidly after the third row. For the middle side of the rice plants, coverage rates of them were maximum at the first row, but decreased rapidly. When one nozzle was tested, C.V. values were in the range of 90~160% and 60~160% on entire heights of rice plant for even flat-fan nozzles and hollow cone nozzles respectively. C.V. values at other parts were poor. Spray coverage rate at the middle part was improved by overlapping the nozzles whereas there was little difference on the upper and lower part of rice plants. (3) For spraying lower part of rice plant between rows, even flat-fan nozzles and hollow cone nozzle were judged as appropriate, but in order to ensure the uniform coverage, distance between nozzles, recommended to be less than 90cm.

• Journal of Biosystems Engineering
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• 제23권3호
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• pp.245-252
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• 1998

The structural characteristics of a small scale rice polisher was analyzed to improve its performance. Spraying characteristic of nozzles used for rice polishing was also analyzed by a machine vision system. The internal pressure of the polishing chamber was measured according to outlet resistance, water spraying, and roller shaft speed. In addition, the performance of the rice polisher was evaluated to improve it in the basis of internal pressure in polishing chamber, whiteness, and broken rice ratio of clean rice according to the operating conditions. Actual nozzle discharge rate and drop size were 125 cc/min and 86~97 ${\mu}{\textrm}{m}$, respectively. In the case of water spraying on rices, the internal pressure showed 4.9~9.8N/$\textrm{cm}^2$ increase. broken rice ratio decreased, and there was no difference in whiteness. The internal pressure inueased up to two times with the increase of the outlet resistance. Also, the pressure at the upper part of screen was one and half times as high as the pressure at the lower part. In the case of water spraying rate of 150 cc/min, the roller shaft speed of 850 rpm resulted in no difference in whiteness and decrease of 0.3% in broken rice ratio, comparing to the roller shaft speed of 950 rpm.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1998년도 하계 학술대회 논문집
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• pp.206-216
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• 1998

The structural characteristics of small scale rice polisher was analyzed to improve its performance. Spraying characteristic of nozzles used for rice polishing was also analyzed by a machine vision system. The internal pressure of the polishing chamber was measured according to outlet resistance, water spraying , and roller shaft speed. In addition , the performance of the rice polisher was evaluated to improve it in the basis of internal pressure in polishing chamber, whiteness , and broken rice ratio of clean rice according to the operating conditions. Actual nozzle discharge rate and drop size were 125cc/min and 86.97㎛, respectively. In the case of water spraying on rices, the internal pressure showed 4.9-9.8N/㎠ increase, broken rice ration decreased , and there was no difference in whiteness . The internal pressure increased up to two time with the increase of the outlet resistance. Also, the pressure at the upper part of screen was one and half times as high as the pressure at the lower part. In the case of water spraying rate of 150 cc/min, the roller shaft speed of 850 rpm resulted in no difference in whiteness and decrease of 0.3%in broken rice ratio, comparing to the roller shaft speed of 950 rpm.

• 한국분무공학회지
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• 제21권4호
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• pp.195-199
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• 2016

Spraying of nozzles and design of tractor-attached boom sprayers have been studied for analysis of liquid spraying features. The following conclusions have been drawn. At all pressures, twin flat spray tips was finer than flat spray tips. A fine spray with VMD of 101 to 200 appeared at 1.5MPa. So, it was selected as the boom sprayer nozzle. In spraying uniformity analysis, Type B was proven to have more uniformity than Type A and Type C at 52.0 cm attached distance. Type A and Type C were proven to have more uniformity than Type B at 58.5 cm attached distance. It is concluded that these results reflect atomizing characteristics of nozzles during pest control with tractor-attached boom sprayer. Therefore, optimum setting will be putting Type C with 58.5 cm distance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.531-536
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• 2005

The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that cost less and are faster than previous semiconductor processes have been developed for the production of electric paper and RFID. The system proposed in this study prints by spraying the molten metal, and consists of a nozzle, heating furnace, operating actuator, and an XYZ 3-axis stage, As an operating system, the piezoelectric(PZT) method has very valuable uses. However, the PZT actuator has a very big hysteresis characteristic due to the ferroelectric characteristics of the PZT element. This causes problems in the system position control characteristics and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. The study proposed a inverse hysteresis model, a mathematic modeling method that can express the geometric relationship between voltage and displacement, in order to reduce the hysteresis of the PZT actuator. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good precision position control performance.

• 한국구조물진단유지관리공학회 논문집
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• 제24권2호
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• pp.9-14
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• 2020

필터가 장착 된 먼지 감소 팬을 포함하여 새로운 유형의 Composite Cyclone Scrubber를 개발하고, 목표 설치 및 유지 보수 비용에 대해서는 기존 도로 오염 저감 시스템 대비 64 %의 투자비 절감 (61 억 원 vs. 170 억 원), 기존 도로 오염 저감 조치 (72.6 억 원) 대비 사회적 비용편익이 43 % 증가, 50.8 억 원)가 예측되고 있다. 장치의 구성은 송풍기 형 나선형 가이드 베인이며, 분사 압력은 미세먼지를 포집한다. 분사 각도 및 접촉 범위가 다양한 노즐, 스프레이 액체 등과 순환 수를 이용한 스프레이이며, 분사 된 물이 Guide Vane과 45도 각도로 충돌로 인해 오염된 가스를 만나기 때문에 41.4 % 더 많은 미세 먼지를 포집한다. 이는 기존의 집진기보다 141 % 증가한 것이다. 포집 액체, 순환 빗물 및 우물 공급원과 관련하여 우리는 특허에서 막대한 양의 에너지와 경제적으로 절약되는 친환경 시스템을 기대한다. 가이드 베인 및 금속 필터는 90 % 이상의 미세 먼지를 줄였으며, 분무 된 물은 베인과 필터를 청소하여 유지 관리 예산을 최소화했다. 개발 된 설계의 예비 평가를 통해 특징적인 물분사로 인하여 유지 보수 예산을 줄일 수 있다.