@article{oai:ir.kagoshima-u.ac.jp:00002080, author = {中富, 葆造 and NAKATOMI, Hozo and 川原, 浩一郎 and KAWAHARA, Koichiro}, journal = {鹿児島大学工学部研究報告, The research reports of the Faculty of Engineering, Kagoshima University}, month = {Sep}, note = {The electroacoustic-type Mill-level meter, developed by the author, indicates a different value according to the size of grain, even when the tube mill is running at the same mill level. As shown in this paper, after experimentally researching mutual relations between the mill level and the size of grain by using a small model mill, the following facts could be confirmed. In case of an air-swept tube mill, the mill-level meter faithfully indicates its mill level, and furthermore there is some linear functional relation between them at the range of normal running (except such a transitional case as mill over or empty mill). Now the result of the study is summarized as follows : (1) If mill level is of the same granulous size, the indication of the mill-level meter has a different value according to the size of grain. Hence, as in the case of a cemment mill, when a given quantity is once thrown into a mill, and is continually crushed without supplying raw materials and exhausting the powdered grain while the mill is in motion, this apparatus can be used as a meter of indicating the granulous size. (2) As an air-swept tube mill has a mechanism in which pulverized coal is exhausted by air-draft while raw coal is continuously fed, it is noticed that coal of many kinds of granulous size is found mixed in the mill. Therefore, if mill level consists of mixed grains of various size, a linear functional relation is established between the indication and the mill level. (3) Taking as an example pulverized coal with a grain size from 0.297 mm to 0.074 mm (48-200 mesh), the coal has the property similar to that of liquid, which gives a lubricating action to a mill ball like oil and a very noticeable effect to the indication. It may be said that character of pulverzed coal whose grain is smaller than 0.074 mm rather approaches a gasious state than a liquid. In fact, these particles manifestly tend to float above the mill level, the influence of which on the motion of a mill ball will be negligible.}, pages = {1--10}, title = {チューブミル用音響式炭面計の指示に対する解析と検討}, volume = {1}, year = {1961} }