Calculation of a multi-effect evaporator by applying enthalpy-concentration diagram, had been reported by several researchers, but their methods were so complicated due to many assumptions on trial, that we felt the necessity of simplifying them.
Our calculation which was based on Matz's theory⁷⁾ consisted of three kinds of balance equation… heat balance, material balance and heat transfer balance…and the enthalpy concentration diagram. The only assumption needed at the start of this trial was the first effect pressure p1, which might easily be derived from Fig. 5 by one or two trials. We then proceeded on with our calculation by using p1 and the next given condition: concentration, temperature and feed rate of liquid to the first effect, the concentration of product liquor, the operating conditions (pressure and temperature of heating steam, number of effect, last effect pressure) and the over-all heat transfer coefficient of each effect. Last of all we derived on trial the necessary values (pressure, temperature and concentration) for each effect, by satisfying the terminal condition that the last effect temperature coincides with the given one. Further more, we easily came to know the heating surface and the liquor temperature of each effect, as well as the steam consumption and the amount of vapor leaving the last effect and going to the condenser.
It must be admitted, however, that the present method is also one of the approximate calculations, because it comprizes errors on drawing and the assumption that the heat requirement in the first effect of the "n" effects evaporator is 1/n of that of the single effect evaporator, having the same amount of product liquor as that of the "n" effects.

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This work was undertaken, with a view to studying the effects which physical properties of liquid … viscosity, surface tension, etc, … have on the wetted area in a packed column. The wetted area for 15-, 25- and 35-mm paper Raschig rings in a 5-in, column was measured by the same method as used by Mayo, Hunter and Nash. Gas rate, up to the loading point, had no measurable effect on it. The values of the wetted area were found to be in agreement with those obtained without gas flow, as shown in Fig. 1.
In this report the values of the fractional wetted area, a_w/a_t, are plotted on logarithmic scales against the liquid rate, L, with surface tension, σ, or viscosity, μ, as parameter. Data are represented by straight lines having the same slope of 1/3, as shown in Fig. 2-6.
For the range of surface tension from 30 to 65 dyne/cm, the fractional wetted area was proportional to σm, and the values of m were -1.07, -0.75 and -0.59 for 15-, 25- and 35-mm rings respectively.
Liquid viscosity had no effect on the wetted area for the range from 0.9 to 3.8c.p., as shown in Fig. 5.
Fig. 9 is the final correlation and shows the values of aw/at plotted against the values of the product L·(σ/20)^3m. All data points fall within ±10% of a single straight line represented by Equations (3') and (4).
The values of a_w/a_t obtained by the previous investigators are shown in Fig. 12, in comparison with the present data. The data by Fujita and Sakuma and those by Mayo, Hunter and Nash show good agreement with the present ones.

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In order to secure the basic knowledge on the vaporization of organic solvents into water-wet air, we studied the vaporization of the same from their wet-bulb surfaces into water-wet air. In the past, only a short discussion has been made on this subject by Colburn and Sherwood in the Sherwood's paper (1932).
Our experimental data are plotted on(t-t_a1) vs. (t-t_w1) diagrams (Figs. 3-7), in which it is shown that for nonhydroscopic solvents (toluene and carbontetrachloride) the wet-bulb temperature ta1 becomes higher than t_a1', when t_wd>t_a1', owing to the water contents in the air. For hygroscopic solvents (methyl alcohol and ethyl alcohol)
t_a1 is always higher than t_a1', so long as the air used is not perfectly dry. Likewise, the effects of water vapor upon ta1 can be represented by linear lines t-t_a1=b+a(t-t_w1), of which a and b are shown in Table 2, induced from the heat balance on the surface of solvent-wetbulbs, as in Equations (1) and (7).
For the humidity charts of toluene, carbon tetrachloride, methyl alcohol, and ethyl-alcohol, the wetbulb-temperature lines might be based on the values (β₀h/k'=)β₀(s_c/p_r)1/2C_H obtained from Table 3 when solvent-wet-bulb temperatures are not affected by water vapor, or on the values(εβ₀ h/k'=)εβ₀ (s_c/p_r)1/2 C_H induced from Table 3 and Fig.9 (a), (b), (c) and (d), when the wet-bulb temperatures change with water contents in the air.
By Lewis h/(k'C_H) for water was shown as approximately equal to 1, but we obtained, for organic solvents, h/(k'C_H)=β₀(s_c/p_r)^1/2>1 or even h/(k'C_H)=εβ0(sc/pr)^/2>>=1 when the effects of water contents were exerted on ta₁.

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Filtering capacity of the continuous vacuum filter varies with its number of revolution.
In the previous paper¹⁾, one of the authors presented their theoretical consideration on the subject together with the charts obtained by calculation. Here they report their experimental verification of it.
The filter employed in the experiment is a simplified type, (Fig. 1). with its drum of 295φ×260. Slurries put to test are sweet potato strach and potato starch suspended in water, with their specific gravities, 10°Bé and 15°Bé, respectively.
Number of revolution is varied from 0.43r.p.m. to 1.87r.p.m.
In this case, the capacity varies with the number of revolution as shown in Fig. 5. We may be able to select the optimum number of revolution by Eq. (14).

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As a continuation of the study described in the previous report^{1), 2)}, crushing tests were carried on by the authors usimg the drop-weight crushing apparatus with the plungers having different weights. The result revealed that the relations previously reported by the authors might be applicable to the present case, too. That is to say, Eq. (1) presented in the previous report might be generally applicable to every case of their experiments, whether with or without plumger weight, and regardless of the difference in crushing conditions, such as drop weight, drop height and so on, provided the value of C in Eq. (2) was constant.

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