• Journal of Biosystems Engineering
• /
• 제31권1호
• /
• pp.39-45
• /
• 2006

Fundamental informations on performance of sets of solenoid valve and nozzle were necessary to develop a target selectable spraying system. The experiments were performed for the sets of solenoid valves and flat spraying nozzles at 3 levels of the operating pressures, and the obtained results are as follows; Rise time of the system pressure to reach up to 90% of the operating pressure after the valve turned was affected by nozzle size and operating pressure. Maximum overshoot of the system pressure was about 170% not affected by the sets of valve and nozzle and operating pressure. The system pressure after its settle down within 5% of the set pressure showed good uniformity in any condition of the experiment as less as 2.3% of its coefficient of variation. Time requirement to lower the system pressure down to 50% after the valve power turned off was affected by valve and nozzle set and operating pressure.

• Journal of Biosystems Engineering
• /
• 제29권3호
• /
• pp.225-232
• /
• 2004

A new type of garlic peeling chamber has been developed which separates and peels garlic cloves using high-Pressure water Jets. The cylindrically-shaped chamber was fabricated with stainless steel plate and has a number of drilled holes, which function as solid-stream spray nozzles, on its interior wall. The chamber was divided into upper and lower section so that water can be applied at different pressures from each section. Three chambers of similar design were tested to evaluate their performances according to various pressure levels. The strongest correlation was observed between the pressure difference(lower-upper) and the proportion of unseparated and completely-peeled garlic cloves. Hanji-type garlic required higher or pressure difference to separate cloves from garlic bulbs than nanji-type garlic. On the other hand, protective leaves(skin) from the cloves were peeled more easily in case of hanji-type garlic. As a result of three consecutive peeling operations, the proportion of completely-peeled garlic cloves changed in the order of 80.1, 82.6, 84.1% in case of hanji-type, and 19.6, 29.1, 40.2% in case of nanji-type garlic.

• Journal of Biosystems Engineering
• /
• 제27권4호
• /
• pp.317-326
• /
• 2002

Characteristics of a twin-fluid spray with ultrasonic vibration were examined in order to obtain a high efficiency of cold-fog spray of the automatic pest control machine which has been widely used in protected horticulture recently. An electrostrictive vibrator of PZT BLT and a magnetostrictive $\pi$-type vibrator were used applied as the ultrasonic transducers with a frequency of 28 kHz. All experiments were conducted in 4 methods of spray ; a conventional spray method without ultrasonic forcing, an indirect vibration method with ultrasonic forcing, an improving-quality method by ultrasonic forced within liquid, and a combined-use method with both of the indirect vibration method and the improving quality method. It was found that the ultrasonic energy increased the atomization efficiency of spray droplets about 10% and especially much more in the case of the combined-use method.

• Journal of Biosystems Engineering
• /
• 제28권6호
• /
• pp.525-530
• /
• 2003

This study was carried out to develop a vacuum nozzle seeder for the automation of large seeds sowing of fruit vegetables and rootstocks. Moreover, the seeding efficiency was examined to find the optimum operating condition considering high precision seeding. The important operating factors for high seeding rate were typically nozzle diameter and absorbing vacuum pressure. The optimum nozzle diameters were found 1.5, 1.5 and 2.0 mm for Chambak, Tuktozwa and Hukjong while the optimum vacuum pressures were 8.0㎪, 10.6㎪ and 5.3㎪, respectively. Under the optimum operating condition, the results indicated that the maximum seeding rates were 97.6％, 98.8％ and 97.6％ respectively for Chambak Tuktozwa and Hukjong. The vibrating acceleration of the hopper did not make any significant effects on the seeding rate when the vacuum pressure reached 8.0㎪ and the sowing rate became higher with lighter seed. As the seed became heavier, the larger diameter of nozzle was recommended 1.5mm of the nozzle diameter was found to be applied for the experimental seeds. The vacuum pressure was also found 8.0㎪ - 13.3㎪ at that time.

• Journal of Biosystems Engineering
• /
• 제29권1호
• /
• pp.21-28
• /
• 2004

Spraying is one of the most efficient methods for pesticide and insecticide control. Generally, orchard sprayers(aircarrier sprayer) are used for such applications. However, when an orchard sprayer is used, only 20% of total amount of spray deposits on the target. The rest of spray are not only wasted but are also potential sources of environmental pollution. The research far the development of electrostatic spraying system for orchard sprayer was conducted to develop the new pesticide application technology for the reduction of environmental pollution and f3r the production of safe agricultural products. The spray characteristics for nozzles with the different charging methods were tested and the effect of electrostatic charge was analyzed, in the laboratory experiments. The results of this study indicate that the capacitive type of electrostatic spraying nozzle exhibits a large current deposition of water sprays on the sample target. The covering area ratio by conventional spraying system was 10.2%, while that of electrostatic sprays with pulse induction charging method gave the increased covering area ratio by 4.3 times.

• 한국산학기술학회논문지
• /
• 제22권2호
• /
• pp.638-643
• /
• 2021

농업분야를 비롯한 식품산업 등 다양한 산업에서 사용되고 있는 오일은 기능성 화장품 개발에도 주요한 원료로 사용되고 있다. 오일은 산소나 빛, 습기 또는 고온에 노출되면 화학적으로 불안정하고 산화되기가 쉬운 특징이 있어 이러한 환경에 그대로 노출되지 않도록 캡슐화하기 위한 다양한 시도가 이루어지고 있다. 오일보다 밀도가 큰 냉매 안에 오일을 주입하면, 오일과 냉매의 밀도차로 인한 부력에 의해 오일이 떠오르면서 오일을 캡슐화 할 수 있는데, 본 연구에서는 이러한 방식의 오일 캡슐레이션 장비를 개발함에 있어 오일 캡슐화의 최적의 장비 구동조건을 찾기 위하여 다상유동에 대한 전산해석을 이용하여 오일 캡슐레이션 현상을 모사하였다. 냉매로는 물이나 세럼(Serum)을 이용할 수 있는 데, 상대적으로 점도가 상당히 작은 물을 냉매로 사용했을 경우는 오일과 물을 지속적으로 주입시키는 방식으로 장비를 구동하더라도 오일액적이 잘 생성됨을 알 수 있었으나, 점도가 매우 큰 세럼을 냉매로 사용했을 경우는 오일이 액적의 형태로 노즐에서 이탈되지 않고 길게 늘어지는 양상을 나타냈다. 세럼을 냉매로 이용한 경우는 오일을 연속으로 주입시키는 방법 대신 짧은 순간 빠르게 주입한 후 얼마의 시간동안 주입을 멈춰 부력에 의해 오일액적을 노즐로부터 이탈시키는 방법을 이용하면 오일액적 생성이 가능함을 알 수 있었다.

• Journal of Biosystems Engineering
• /
• 제36권6호
• /
• pp.434-443
• /
• 2011

A large scale seeding system was stable in terms of techniques but a convenient seeding system of small size was unsettled. This study was performed to develop a semi-automatic seeder for small and medium sized scale farm. To investigate optimum needle diameter and vacuum pressure was used vacuum suction needle seeder. Although the needle diameter according to the kinds of seed was different, the needle diameter for salvia and lettuce seed was suitable for 0.34 mm needle nozzle and 0.4 mm taper nozzle. The prototype consisted a seeding frame attached with needle nozzle, seed hopper, vibrating device, seeding part, vacuum ejector, seed tube etc.. As the result with the experiments, the seeding rate of the seeder was 92% and more at 0.34 mm diameter needle nozzle and 0.4 mm taper nozzle. Eccentric weight for seed hopper vibration was suitable that weight is 11 g and eccentric distance is 0.5 mm. Vibration acceleration of upward direction was 0.363 m/$s^2$. Working capacity of the seeder was possible 160 trays per hour. It was possible for sowing small seeds but it was required to make compact and simple model.

• Journal of Biosystems Engineering
• /
• 제20권4호
• /
• pp.313-322
• /
• 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
• /
• 제33권3호
• /
• pp.179-185
• /
• 2008

The seeding rates of the vacuum suction nozzle seeders are affected by the jumping height of the seeds on the vibrating seed hopper. This study was performed to investigate the optimum vibration condition of the seed hopper on the vacuum suction nozzle seeder for improving seeding performance. Experiments were carried out to determine the vibration conditions of the seed hopper by air pressure and eccentric weight, and to optimize the seed-pickup performance of each nozzle by suction pressure. As the result with the experiments, the fluctuations of the jumping height of the seeds were showed at amplitude 0.4 mm and frequency 42 Hz, and jumping heights of the seeds were increased as the air pressure increase and the eccentric weight decrease, regardless number of seeds of the hopper. The best seeding rate of the seed hopper was 98% at the 300-seed cell, when the condition of the seed hopper was the suction air pressure of 94.6 kPa-abs., amplitude and frequency of the seed hopper vibration were at 0.57 mm and 43.6 Hz, respectively. The optimum vibrating conditions of the seed hopper were decided into frequency 43.6-43.8 Hz and the amplitudes 0.61-0.62 mm.

• Journal of Biosystems Engineering
• /
• 제31권3호
• /
• pp.153-160
• /
• 2006

This study was performed to evaluate some geometrical characteristics of disc type swirl nozzles and to develop nozzles having improved spraying performance for knapsack sprayers. Considered geometrical characteristics of the nozzles were disc thickness, orifice diameter, swirl chamber diameter and shape of the swirl chamber (nozzle chamber). 3 types of nozzle cores were compared. Main results of this study were as follows. 1. Spraying angle (A) was increased with decreasing disc thickness (x), and with increasing orifice diameter (y) or spraying pressure (z). The equation was as a follow. $$A=3.95\frac{1}{x}+73.50\sqrt{y}+18.97\sqrt{z}-60.16$$ 2. Spraying flow rate (F) was increased with decreasing disc thickness (x), and with increasing orifice diameter (y) or spraying pressure (z). The equation was as a follow. $$F=-89.95x+611.09y+620.49\sqrt{z}-868.20$$ 3. Mean spraying droplet size (V) was decreased with decreasing disc thickness (x), with increasing orifice diameter (y) in low spraying pressure, with decreasing orifice diameter (y) in high spraying pressure, and with increasing spraying pressure (z). $$V=148.77x^4-746.85x^3+1311.76x^2-917.31x$$ 4. The spray pattern was compared using CV values. The CV value of the nozzle core type 1 was 26.7% in spraying pressure $3\;kgf/cm^2$, the CV value of the core type 2 was 23.6% in spraying pressure $2\;kgf/cm^2$, the CV value of the core type 3 was 20.6% in spraying pressure $1\;kgf/cm^2$. 5. Minimum spraying pressure was improved from $1.5\;kgf/cm^2\;to\;1.0\;kgf/cm^2$ by changes of nozzle core shape.