頁籤選單縮合
| 題 名 | 靜置式稻谷乾燥機應用雙向送風乾燥之研究 |
|---|---|
| 作 者 | 馮丁樹; | 書刊名 | 農業工程學報 |
| 卷 期 | 26:2 1980.06[民69.06] |
| 頁 次 | 頁89-103 |
| 關鍵詞 | 乾燥機; 稻谷; 靜置式; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 靜置式乾燥最大之缺點是穀層乾燥不易均勻。目前雖部份改成稻穀循環乾燥方式,但價格昂貴,難以普及。因此,就現有箱式乾燥機加以改良,實未失為一種經濟可行之方法。 為達此目的,往復通風乾燥方式可說是最佳之答案。往復通風方式係穀物靜置,而熱風之方向則定時以機械方式加以反向,使上下穀層均能獲得均勻之乾燥效果。此種反覆風向之觀念應用於稻穀乾燥可謂第一次。其基本應用條件是在熱風溫度不能過高,穀層厚度不能過大之場合,方可獲得優良之效果。而此項條件又頗適合於箱式乾燥。 本試驗主要目的乃在瞭解往復通風乾燥方式應用於稻穀乾燥時之各項因素變化。並依熱風溫度(45℃,40℃),穀層高度(50公分,45公分)、反覆時間(1小時,2小時)以及風量大小等因素加以控制,再逐步討論各因素對水分含量分佈與胴裂率之影響。 由試驗資料可知,只要溫度不超過45℃,全胴裂之增加率將低於10%,約僅及單向通風乾燥方式之四分之一。在水分佈上,水分差異則僅及單向者之一半,均勻度甚為良好。 稻穀之堆積高度應低於45公分,以30公分為最佳。厚度過大,水分差異變大,胴裂率也增高為最佳。厚度過大,水分差異變大,胴裂率也增高。此外,風量增大,雖可增加乾燥速率,但胴裂率相對增加。 根據本試驗所得資料顯示,往復通風乾燥方式應為目前靜置乾燥之較佳方式,但其反覆時間不應過短,適當之時間應在二至三小時左右。 |
| 英文摘要 | The main shortcoming of rice driers with stationary bed that always discourages the buyers is that the grain moisture within grain layers can hardly be reduced to a reasonable uniform range after drying. In general, the extreme moisture contents of rice grains in this type of driers would be four to five percent far from the desirable value, which would consequently induce lots of cracks on grain kernels if more even distribution of grain moisture is expected. Under such circumstances, both farmers and the Food Bureau men have been annoyed with this problem quite a long time and can not help encouraging the new buyers to choose the circulating type instead, which, nevertheless, still has a long way to become popular here in Taiwan because of its high cost. Therefore, the most economical and feasible way is to remodel the present small portable box-typed driers that fifteen thousand farmers have already owned for now. To solve this problem, however, we conclude an idea for this shallow bed drying by reversing the hot air directions either upward or downward, which can be controlled intermittently in every two hours. In order to prove that this idea works, we made both laboratory and field drying tests and results were very convenient and satisfactory. During this experiment, four factors are controlled and each has two levels, to see their influences upon the rice quality and moisture behavior. These four parameters include grain depth (45 cm & 30 cm), air temperature (45℃ & 40℃), the reversing period, (one & two hours), and air flow rate (0.05 CMM/kg & 0.15 CMM/kg), In each experiment, the grain moisture and kernel cracks are investigated and besides, grain temperatures are also recorded. According to the data obtained, we found that the total crack ratio will be lower than 10%, which will only be one quarter of those using continuous bed drying, as long as the air temperature is not higher than 45℃. It is very obvious that air temperature is a powerful factor in controlling cracks. It would affect, but not much, the moisture gradient throughout the grain bed, too. However, as compared with the one-way drying method, this new method has shown its advantage on controlling the discrepancy of gain moisture. Very uniform moisture distribution in grain bed has been found after drying . However, the grain depth still plays a restrictive role as it does in the one-way drying method. Generally, the grain depth should not be higher than 45 cm if result is expected to be satisfactory, and the deeper the drying bed, the lower the air temperature should be used. The deep grain layer may not only cause greater discrepancy of moisture, but also increase the crack ratio. Just as we have expected, high air flow rate will increase the drying rate constantly, because tempering period is involved in this method, however, it will also increase the crack ratio. In all, according to this experimental result, we know the appropriate operations for wet paddy drying are very important. We must carefully changing the air directions at least every two hours and gradually decrease the air temperature to 40℃ throughout the whole drying period. However, judging by the data we have, we conclude that this two-way drying method might be the best way to improve the present box-typed rice dries in Taiwan and could leave us to utilize the solar energy for drying in future. |
本系統中英文摘要資訊取自各篇刊載內容。