Yoshikazu Nakada.
-Every blast furnace man desires to avoid of the beakout from the blast furnace if possible, because it spoils a great deal of furnace conditions and may accompany sometimes dangerous to men. It is a very popular fact that at the tip of an inhaler, owing to a strong flow of steam, there occurs a pretty powerful depression, by which a volume of water in a vessel putdownward, can easily be sucked up. A similar phenomenon may occur, too, at the tuyre end in blast as everyman can easily understand. In the latter case, however, instead of water, some hghly heated molten materials will be drawn up or from the other point of view, they will attack against a tuyre tip, where a depression occurs, and bring this at last to break.
The stronger the blast, the more mighty the depression, and an impinging action will become more effective. It is able to say therefore that the blast is a powerful destro ger of tuyres.
Naturally almost all pant of blast blown in, flowa directly upward along its upper lip and not any along the lower pant. This upward flow serves to disturb or weeken the depression and to blow about, too molten materials comming to tuyres, but on the contrary not any at the lower. Thus it will be able to explain why breakouts occur mostly, as every man see, at their lower lips. Intending to avoid the paltial upward fllow of the blast and disperse it for all directions, the tuyre end is cut on the bias as shown on a sketch. With the new form the lower. end being shorter, a flow begines earlier from the point "b" and natully this flow takes its way somewhat downward. An inclination "α" has duty to keep always the direction of the tuyre and the flow, too, down ward, even such a case that the tuyre will be thrusted up by growing up of the breast wall very possible by heat.
The following comparison tells us how much the improved tuyre gave a good result. "a" blast furnace. Kamaishi.
On sep. 26^th. 1926 all tuyeres were changed with the new forms and after that the breckout has reduced to onesixth while the production increased to 111.5% having compared with the last four mouths.

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Mikio Mukaiyama.
-The production of pig iron in electric furnaces might be considered as essentially different from that of the ordinary blast furnaces, from a theoretical point of view. Here, the auther predicates on the theory of the production of pig iron that the essential differences in the two processes, are the equilibrium of the system and the velocity of the reaction, i.e. in electric furnaces the chemical equilibrium of the system is the dominating factor for the quality (composition) of the finished product and therefore its structure, and in the ordinary blast furnaces, the reaction velocity plays the most important role.
After a discussion of the mechanisms of the production of pig iron in electric furnaces theoretically from this stand point, the auther made many experiments dealing with the reduction under a constant pressure of carbon-monoxide gas at different temperatures in an electric furnace, especially for the absorption of carbon and the reduction of silicon, which are, generally, accepted as the most important elements in pig iron.
As a result of the experiments, he was able to create a space model about the equilibrium of the system.
By means of this model, one can easily and exactly find the conditions for the smelting of iron ore in electric furnaces for a given composition of pig iron.
The bases of this new space model are given in the following short explannations.
(I). For silicon content in pig iron, the auther states that the reduction of silica to silicon with solid carbon should be a reversible reaction. Therefore, the reaction attains its equilibrium for each temperature, under a constant pressure of CO gas, i.e. SiO₂+2C Si+2CO Then, the higher the temperature and the concentration of SiO2 in slag, the greater the concentration of Si in pig iron. And the concentration of Si in pig iron is dominated by this equilibrium, in spite of its large solubility in molten pig iron.
(2). The system is bivariant under a constant pressure.
(3). For the carbon content in pig iron, he mentions that the absorption of carbon in pig iron is due to its solubility in iron, which changes with both the temperature and the concentration of silicon in the iron. That is, the higher the temperature and the smaller the concentration of Si, the larger is the solubility of carbon in pig iron.
He made demonstrative experiments on an industrial scale with a 3 phase-200.K.W. electric furnace by smelting magnetic sand. By means of the new space model, he choiced several kinds of slag for the refining of the magnetic sand and at certain temperatures and under a constant pressure, he could produce pig iron of the expected composition.

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