The thickness of the water film falling on a vertical flat surface with countercurrent air flow was measured by the modified Dukler-Bergelin method using electrical capacitance. At the same time, quantitative data on wave motion on the falling film were obtained by the same technique using oscilloscope photographs. The resuits obtained are summarized as follows:
(1) Experimental values of increment of film thickness due to countercurrent gas flow agree closely with the values predicted from the modified Lamb equation over laminar and turbulent regions.
(2) The effects of ReL and ReG on statistically treated vaiues of wave height are representedby the following equations:

View full abstract

1) An empirical equation by which to calculate the power consumption of paddle-agitators were obtained as follows:
(27)
where
(19)
(22)
(23)
This equation has a wide range of applicability with slight errors.
The powers consumed by the impellers having various number of blades can be calculated by the method of approximation mentioned in the previous report¹⁾.
2) The maximum power consumption of paddle-agitators can also be calculated by Eq. (27), in which for Re are substituted the values of R_c, and R_θ obtained from the following equation.
For the paddle having a blade angle of 90°,
(28)
For the paddle having an arbitrary angle of θ,
(30)
3) Fairly good agreements were obtained between those values calculated by the equations and those obtained by the experiments.

View full abstract

The author¹⁾ had previously proposed a chart for finding the pertinence of some variables which are necessary for design and operation of aclosed-circuit grinding plant. The ideas was based upon some assumptions, of which the most important but mostvulnerable was that the feed powder would be completely divided into two parts fine and tailing with x_o as a parting size. This fictitious condition, however, does not apply to every classifier.
The present paper deals with a general use of the chart, with a new idea (a) expressing more concisely the performanco of a classifiert than the coiventional separating efficiency.The new idea (a) has been defined as the ratio of the specific surface of actual tailing which would be obtainpd if the ideal separation described above should take place.
According to the new concept, the parting size x_c is defined as the one at which the weight of the finer particles in the tailing becomes actually equal to that of the coarser ones in the fine, that is
where R, D are over-and undersize, suffixes T and P refer to the tailing and fine, respectively, and Cl is the circulating load, which is equal to T/P.
The following equation is assumed to be applicable to the particle size distribution of the taillng,
where x_a and k' are functioms of mand the circulating load Cl, respectively, and m is determined as the function of Cl and a. Hence index a will enables us to obtain not only the figures abeut an actual specific surface of the tailing and the fine, but their approximate size distributions from the chart, which was made on the assumption that the ideal separation could be established.

View full abstract

The work was undertaken to determine the reaction rates of the catalytic hydrogenation of 2-ethyl-hexen-2-aI-I in the vapor phase. Rates of the reactions were measured over a range of space velocities (0.2-4.0) and temperatures (150-200°C), using the meta1-oxide catalyst. When the reverse reaction is taken into consideration the reaction rates are expressed by the following equations;
rCHO: the reaction rate of the hydrogenation of aldehydes
r_F: the reaction rate of the hydrogenation of species containing a double bond
While the proposed rate-equations afford no information as to the interactions of reactants and products with catalyst, and hence as to the true mechanism, the results do provide us with a method of predicting the reaction rates over a range of operating conditions investigated. This information should be of value in designing commercial reactors. The optimum operating conditions were also determined for the reactor designed.

View full abstract

[in Japanese]

View full abstract