The practice of carrying melted cast iron direct from the blast furnace
to the Siemens hearth or the Bessemer converter saves both money and
time. It has rendered necessary the construction of special plant in the
form of ladles of dimensions hitherto quite unknown. Messrs. Stevenson &
Co., of Preston, make the construction of these ladles a specialty, and
by their courtesy, says _The Engineer_, we are enabled to illustrate
four different types, each steel works manager, as is natural,
preferring his own design. Ladles are also required in steel foundry
work, and one of these for the Siemens-Martin process is illustrated by
Fig. 1. These ladles are made in sizes to take from five to fifteen ton
charges, or larger if required, and are mounted on a very strong
carriage with a backward and forward traversing motion, and tipping gear
for the ladle. The ladles are butt jointed, with internal cover strips,
and have a very strong band shrunk on hot about half way in the depth of
the ladle. This forms an abutment for supporting the ladle in the
gudgeon band, being secured to this last by latch bolts and cotters. The
gearing is made of cast steel, and there is a platform at one end for
the person operating the carriage or tipping the ladle. Stopper gear and
a handle are fitted to the ladles to regulate the flow of the molten
steel from the nozzle at the bottom.
[Illustration: LADLES FOR CARRYING MOLTEN IRON AND STEEL.]
Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It
requires no description. Fig. 3 shows a tremendous ladle constructed for
the North-Eastern Steel Company, for carrying molten metal from the
blast furnace to the converter. It holds ten tons with ease. It is an
exceptionally strong structure. The carriage frame is constructed
throughout of 1 in. wrought-iron plated, and is made to suit the
ordinary 4 ft. 8½ in. railway gauge. The axle boxes are cast iron,
fitted with gun-metal steps. The wheels are made of forged iron, with
steel tires and axles. The carriage is provided with strong oak buffers,
planks, and spring buffers; the drawbars also have helical compression
springs of the usual type. The ladle is built up of ½ in. wrought-iron
plates, butt jointed, and double riveted butt straps. The trunnions and
flange couplings are of cast steel. The tipping gear, clearly shown in
the engraving, consists of a worm and wheel, both of steel, which can be
fixed on either side of the ladle as may be desired. From this it will
be seen that Messrs. Stevenson & Co. have made a thoroughly strong
structure in every respect, and one, therefore, that will commend itself
to most steel makers. We understand that these carriages are made in
various designs and sizes to meet special requirements. Thus, Fig. 4
shows one of different design, made for a steel works in the North. This
is also a large ladle. The carriage is supported on helical springs and
solid steel wheels. It will readily be understood that very great care
and honesty of purpose is required in making these structures. A
breakdown might any moment pour ten tons of molten metal on the ground,
with the most horrible results.
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APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE
SURFACE OF CONDUCTORS.
Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and
ingenious apparatus which permits of demonstrating that electricity
develops only on the surface of conductors. It consists (see figure)
essentially of a yellow-metal disk, M, fixed to an insulating support,
F, and carrying a concentric disk of ebonite, H. This latter receives a
hollow and closed hemisphere, J, of yellow metal, whose base has a
smaller diameter than that of the disk, H, and is perfectly insulated by
the latter. Another yellow-metal hemisphere, S, open below, is connected
with an insulating handle, G. The basal diameter of this second
hemisphere is such that when the latter is placed over J its edge rests
upon the lower disk, M. These various pieces being supposed placed as
shown in the figure, the shell, S, forms with the disk, M, a hollow,
closed hemisphere that imprisons the hemisphere, J, which is likewise
hollow and closed, and perfectly insulated from the former.
[Illustration]
The shell, S, is provided internally with a curved yellow-metal spring,
whose point of attachment is at B, and whose free extremity is connected
with an ebonite button, K, which projects from the shell, S. By pressing
this button, a contact may be established between the external
hemisphere (formed of the pieces, S and M), and the internal one, J. As
soon as the button is left to itself, the spring again begins to bear
against the interior surface of S, and the two hemispheres are again
insulated.
The experiment is performed in this wise: The shell, S, is removed. Then
a disk of steatite affixed to an insulating handle is rubbed for a few
instants with a fox's "brush," and held near J until a spark occurs.
Then the apparatus is grasped by the support, F, and an elder-pith ball
suspended by a flaxen thread from a good conducting support is brought
near J. The ball will be quickly repelled, and care must be taken that
it does not come into contact with J. After this the apparatus is placed
upon a table, the shell, S, is taken by its handle, G, and placed in the
position shown in the figure, and a momentary contact is established
between the two hemispheres by pressing the button, K. Then the shell,
S, is lifted, and the disk, M, is touched at the same time with the
other hand. If, now, the pith ball be brought near S, it will be quickly
repelled, while it will remain stationary if it be brought near J, thus
proving that all the electricity passed from J to S at the moment of
contact.--_La Lumiere Electrique_.
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