The alteration of the system of cooling the ingots allowed scrap for reasons of surface quality to be com- pletely eliminated. Under the new system of cooling the speed of the belt should not exceed 8-9 m / m i n with ingots weighing 45-50 kg and 12-14 m / m i n with ingots weighing 25 kg; in addition, in places of constriction an ingot weighing 25 kg should have a thickness of 20-25 mm, and one weighing 45-50 kg should have a thickness of 25-30 mm.

Our experience indicates that in order to obtain ingots with good surface quality the following conditions should be met:

1) The cooling of the iron on the casting machine should begin after solidification of the surface. 2) The cooling intensity shoutd be minimum at the beginning and a maximum at the end of cooIing.

AN E L E C T R I C S A F E G U A R D A G A I N S T

FOR THE ORE C H A R G E

V. E.

Translated from Metallurg, No. 8, pp. 10-11, March, 1962

O V E R F I L L I N G THE HOPPER

The hoppers of the blast-furnace ore scales for various reasons become overfilled, leading to the filling in of the skip pit for the ore charge and occasioning long furnace standstills while the pit is cleaned of charge, tn particular instances the standstills last six hours and more.

In the Magnitogorsk Metallurgical Combine, on the recommendation of A. V. Meshkov, P . I . Kosukhin, N. P. Pogozhikh, and D. S. Konishchev, an electric safeguard (Fig. g) was installed onthe hoppers ofthreeblast furnaces in order to eliminate the standstills related to the overfilling of the hoppers. An opening is cut in one of the walls of the hopper (the north) and a lever with a paddle is inserted into the hooper. The paddle is held back in hinges; a weight deviates it to a position corresponding to closed contact of the electric circuit of the mechan-

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Fig. 2. Arrangement of the safeguard against overfilling of the hopper at the scales. 1) Hopper; 2) lever with pad- dle; 3) contact; 4)weight.

ism feeding material into the hopper. The location of the paddle cor- responds to the level of maximum filling of the hopper. Under normal operation the material does not reach the level of the paddle, When the hopper is overfilled, the material presses down the paddle with its weight and thus switches off the transporting mechanisms, Further weighing is possible only after intervention of the machine operator.

The introduction of this improvement eliminated standstills of the blast furnaces for reason of filling in the skip pit, which for only three furnaces saved about 6000 rubles per year, .The improvement is to be recommended for use at other plants as well,

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