高級モグサを製造するとき最後の精製を行う装置がである。
モグサ用とは異った構造の特殊な装置である。主要部分は, 高速度で回転する羽根車, 羽根車を取り囲む大きな円筒状の竹の箕及びこれを納める木製の箱型構造体から出来ている。
粗製モグサをに入れ, 羽根車を1分間70～120回の高速で回転すると不純物は簀の間隙から外へ排出され, 簀の内部には高級モグサが残る。
通常は先ず一番目ので粉状の不純物を大体除き, 二番目ので精製を仕上げる二段階方式をとる。所要時間は3～8時間であるが, 条件によっては更に増減がある。

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The purpose of this study was to investigate fundamentally the effects of curved blade shapes, and their unloading characteristics. Three curved blade shapes (Fig. 1), which could be designed for use in this winnowing fan, were selected. The radial and backward slant blades were selected in addition to the forward curved blades in order that three basic shapes could be studied. The results were as follows:
1. In each opening of the air suction port, the backward slant blades required the least power and the forward curved blades the most.
2. The overall efficiency of the forward curved blades is better than the others, because they required less power to obtain the same wind velocity. The highest efficiency may be obtained at the opening No. 3.
3. The vertical distribution of wind velocity is lower at upside than down side of the delivery port. The horizontal distribution of wind velocity is similar to the U type. The rate of wind velocity deviation is about 5% of the four blades fan at the opening No. 2.
4. The forward curved blades, cut both end obliquely, have equalized the horizontal distribution of wind velocity.

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(1) In order to survey the distribution of mean wind velocity and intensity of turbulence in the winnower, a set of recordihg hot wire anemometer is built.
(2) The anemometer consists of a pair of platinum hot wire with the diameter of 0.025mm, a bridge circuit, a D-C amplifier and a recorder.
(3) The measurement of mean wind velocily is done by means of so called constant resistance method, and the turbulence by constant current method.
(4) A calibrating wind tunnel, composed of a fan, guide tunnels, an orifice, a tapered tunnel, a measuring tunnel and a strainer, is constructed to calibrate the anemometer.
Calibration is performed by comparing the reading of the anemometer with that of the pressure difference led from the orifice, which had already been calibrated by comparing with the standard Pitot-static tube.
(5) The reading of mean wind velocity gotten by the anemometer may include the error estimated as 2.5%.
(6) The altitude of output may include the error evaluated as 4.0% caused by the imperfection of the compensation to the characteristics of hot wire, when frequency of turbulence is 50c/s.
(7) The error derived from the non-linierity may occur if the altitude of turbulence grows more thon ±0.7m/s.
(8) The pen-writng oscillograph is employed for the reason of the convenience of handling. In this case if the error which amounts to ±10% is permissible, the frequency range of DC-50c/s is measurable.

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To decide the air current of pneumatic separating path, the author applied Professor S. I. Pai's theory which found out phenomenon of the turbulent flow between two parallel plates, and decided that current of wind path was either turbulent flow or laminar flow, and in addition, drawn up the theoretical wind velocity curve.
In consideration, the author applied variation value and mean value of mean wind velocity, discharge quantity and pressure at the Reynolds equation about three direction at standard middle part in wind path, and satisfied the Navier-Stokes equation in similarly. But these differential equation had many unknown value, and so, the author gave boundary condition and solved it. There are four method in deciding these equation, and we adopted the case that the velocity of upper and lower part of wind path was unequal, because this case was the most often in the winnower. In this case the author considered influence of coefficient of friction and also used the Laufer's experimental curve of turbulent flow. On the experimental machine, the wind velocity was found by convert of cordinate about not only the section of advance direction of wind but also the section of breadth direction of wind path, calculated minutely about the main or vice winnower. From the graph of these results, the mean velocity was gotton by measuring of area.
For conclusion, [1] the author known either turbulent flow or laminar flow from wind velocity of two or three points, and it could be judged apart Reynolds number.[2] This application, applied to the condition of Poiseuilli's flow, was induced theoretically both distributing curve of wind velocity and equation, and was gotton about more complicated winnower's wind path than ordinary fluid machines.

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On the occasion of two viscous turbulent flow in the theory of turbulence boundary layer cause the incompressive symmetric mixing flow at the contact point, the thickness of mixing range of turbulence was decided. The winnower breadth was calculated by induction method, and the author checked up whether this breadth was suitable or not.
The calculation of winnower breadth was made to apply the mean velocity of turbulent flow that was in measuring points of air velocity by previous report. The maximum permissible length was decided by drawing curve parallel to curve that measured the real height at points of grain separation.
The calculation was applied at the inlet point, the grain flowing plate, and the way out of main winnower and sub-winnower of the experimental rice huller.
As the result, this condition was fully satisfied, because the practical breadth at each way out was smaller than the calculated size.

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1. The dust generated under hulling-work, not only ruins worker's health but also spoils mechanical function.
There upon, we devised, as its counter-measure, the dust elimination equipment that was manufactured in trial and then tested some experiments on it.
2. We observed the direction of air current in side same time measured the distribution of wind velocity within and without.
3. To show the effect of dust elimination, we temporally use the word dust elimination efficiency
η%=(q/Q)×100……(1)
Note: η……Duste limination efficiency
Q…The whole quantity of dust eliminated(g)
q…The quanty eliminated from all the dust generated(g)
4. By substituting the figures obtained of experiment in formule (1) we verified that its effect was great, the dust elimination efficiency representing 87.5% or an average.

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