|Title:||農試型循環式稻穀乾燥機之研究與試造||Other Titles:||Experiments on Tart-Type Tempering Dryer||Authors:||鄔清標
|Issue Date:||1-Dec-1977||Publisher:||農業試驗所||Journal Volume:||26||Journal Issue:||4||Start page/Pages:||255-278||Source:||中華農業研究||Abstract:||
1. 展循環式乾燥機，使乾燥中稻穀自動循環，一次乾燥量1.5~3噸，動力110V, 1-2HP馬達，適合個別農家、碾米廠或共同經營使用。其乾燥性能可兼用於搶救及一般乾燥，結構力求簡化適用以降低生產成本。
(4) 升穀機：使用杓瓢式提運機(Bucket elevator)較適合，但其揚穀量應注意滾筒的間歇性漏谷，高低含水率穀的流動差異性等安全係數，又皮帶以外層橡膠內層帆布者較能適應水份的影響及各種負荷的變化，以防打滑及阻塞。
Y=0.1187x+0.551 Y:當天重胴裂增加數(%) X：乾燥速度(%/hr)
This is an automatic circulation dryer developed under this project. The capacity of this dryer is 1.5 to 3 tons equiped with an electric motor of 110V and 1 to 2 HP. This dryer is suitable for individual farm household, rice mills orcooperative farms. One of the function of this dryer is for quick drying during rainy season, the other is for general purpose. The structure of this dryer is simple, so that the production cost can be reduced.
(1) Grain flow control system
(a) Metering rolls like a star in section and a screw elevator are adopted.
This kind of combination of flow control system performed very well. However, the structure is very complicated and the star type rolls will be clogged easily by broken rice panicles and small stones mixed with the rice grains. In the meantime, since the flow speed of wet grains in the very beginning and in the end of the process are different a lot, and the grain f low are moved intermittently during the process. Hence, the elevator is easily stopped.
(b) The star type metering rolls and a declined collecting board are adopted.
The structure of this system is simple than the previous one, however, this combination has the same defects mentioned above. Since there are considerable side pressures on the board, the wet grain flow will not be moved so easily on the board. This system is suitable for the square or column type grain dryer.
(c) Screw elevator control system is adopted.
The flow control of this system is very accurate and simple in structure. This system is suitable for rectangle type grain dryer. A variable screw pitch or a variable diameter of the screw or both are needed, so that a uniform grain flow will be achieved in the front as well as in the rear of the whole system. In the meantime, an adjusted plate is needed to be attached to both of the front and the rear of the system so as to control the grain quantity in the inlet and in the outlet of the dryer.
(2) Grain distributor in the upper of the bin
There are two kinds of grain distributors, one is the declined board type which is suitable for square or round type bin. The other kind of distributor is the screw type which is suitable for the rectangle type bin. Since the screw type distributor can only spread the grains linearly, therefore, an auxiliary attachment is needed when the short side of the bin is not so short.
(3) The inlet and the outlet of heat flow
The relative position and pattern of the inlet and the outlet of heat flow are very important factors for drying functions of the dryer. When the inlet and the outlet are nearly in the same level, the heat flow will pass the grain in a very short time, and the heat flow will be lost a lot, on the contrary, when there is a considevable height between the inlet and the outlet, the heat efficiency will be high, however, the broken rice will be increased also, moreover, the grains will become wet again when rice grains are high moistured. It is difficult to map a definite pattern of them because these factors such as the moisture content of grains, the quantity and the temperature of heat flow, circulation quantity of grains and the atmosphere conditions can effect the whole result. We arrange that the inlet is below the outlet in the very beginning, then we set the inlet and the outlet in the same level latter, finally, we set the inlet and the outlet in the same level, but the inlet is divided into two parts which can be adjusted freely as indicated in picture 12. This final arrangement can be met the necessity when the cereal capacity is varied.
(4) Grain elevator
The bucket elevator is very suitable for this dryer. However the capacity of this elevator should be met the character of intermittent flow of the star type roller, and different flow speeds of grains with different moisture content. The belt of the elevator is better made of rubber outside and cloth inside so to met the wet condition and various loads. This arrangement can prevent slippage and stoppage.
3. Drying function
(1) Moisture content 23-13%, heavy broken rice 5% after drying, ponlai rice.
(2) Moisture content 23-13%, heavy broken rice 10% after drying, ponlai rice.
(3) Moisture content 23-13%, heavy broken rice 5% after drying, native variety.
4. Drying cost:
The grain drying cost is NT $ 0.23-0.60 per Kg (rice moisture content 23-13%). The drying cost will be lower than the horizontal box type dryer if this grain dryer is properly used. However the cost of drying of this dryer will be still higher than the solar drying in southern Taiwan.
The excess cost of drying between this dryer and the solar drying is almost equal to the grain loss each year during the rainy season. Moreover, this grain dryer can be operated together with the rice combine in the same time.
|Appears in Collections:||1.台灣農業研究(1950～迄今)|
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