292 
NATURE 
[ Fan. 13, 1870 
THE BESSEMER PROCESS UNDER 
PRESSURE 
h R. BESSEMER has lately patented a method of conducting 
V1 his process of converting cast-iron into steel wnder pressure, 
in order to raise the temperature of the metal during the process | 
of conversion, and to obyiate the inconvenience experienced when | 
ce-tain of the purer qualities of Swedish pig-iron made with | 
charcoal, and also some of the less grey and the white hematite 
pig-irons of this country, when treated by the ordinary process, 
do not produce sufficient heat in the converting vessel to allow 
all the steel made from them to retain complete fluidity until 
it is poured into moulds. 
The following description of the apparatus is extracted from 
Engineering, to the editor of which journal we are indebted for 
the use of the woodcuts. 
In the annexed engravings, Fig. 1 is a vertical section of a 
Bessemer converter constructed on this plan, a being the upper 
part of the converting vessel; ax, the lining of ganister; and 
' i ary ee 1 ene Satyr = 
g, the strong riveted iron shell or vessel on the inside of the ! flanges, #1, and one or more hoops, 
mouth of which the iron hoop, ¢, is riveted; while ¢@ is a 
flanged iron ring bevelled on the inside, and secured by screwed 
studs or cotter bolts to the hoop, «. A moulded ring, ¢, of fire- 
brick or other suitable refractory material, forms the escape 
opening or mouth of the vessel ; it is retained in place by means 
of the flanged ring, d. : 
Che aperture in the movable mouth of the vessel thus formed 
may in some cases be made small enough to retain the gaseous 
products resulting from the combustion of the carbon or other 
matter contained in the pig-iron under a pressure much above 
that of the surrounding atmosphere, so that the combustion 
going on in the converting yessel may be under “high pressure,” 
anl by reason of the combustion so taking place under a 
pressure much greater than that of the external atmosphere a 
more intense heat would be produced and imparted to the metal. 
As a guide to the workmen, Mr. Bessemer states that for the con- 
version of the purer kinds of Swedish charcoal pig-iron and for 
mottled or white hematite pig-iron mixed with grey a back pres- 
sure in the vessel from $ to 15 lb. on the square inch will give 
good results, and in but few cases will a pressure of 2olb. per 
square inch be necessary. It will be understood that the pres- 
sure of the blast of air forced into the converting vessel must be 
increased in proportion to the back pressure caused by the pen- 
ning up of the gases within the vessel. 
Another arrangement is illustrated in Fig. 2, which represents 
| a vertical section of the upper portion of a converting vessel or 
chamber in which molten pig or other carburet of iron is to be 
treated either by the injection of the fluid nitrate into the molten 
metal, as patented by Mr. Bessemer in March last, or in which 
vessel the nitrates or other oxygen-yielding salts or substances 
are so brought in contact wlth the hot metal as to be decom- 
posed. The outer shell, Z, of the vessel or chamber is made of 
thick plates of iron or steel securely riveted and caulked at all 
joints, and capable of withstanding safely a pressure of from five 
to ten or more atmospheres. For the convenience of lining the 
vessel, the upper part may be removed by unbolting the stout 
h®, are riveted to the ex- 
terior of the vessel to strengthen it. 
ganister, or other refractory material, 7, is used to defend the 
outer shell from the high temperature generated within ; and pre- 
A lining of fire-brick, 
vious to its use for conversion, Mr. Bessemer prefers to make a 
fire in the interior, so as to highly heat the lining and lessen its 
power of absorbing heat from the metal. 
On the upper part of the dome an iron ring, 7, is riveted, 
to which a flanged ring, 7, is fitted. The inside of this ring is 
conical, and is made to embrace the conical fire-clay ring, 7, 
through which the gaseous matters evolved during the process 
are allowed to escape. A cone of fire-clay or of iron, g, is at- 
tached to the guide rod 7, for the purpose of closing or diminish- 
ing the area of the outlet opening in the fire-clay ring 7, and on 
the upper end of the rod 7 are placed weights, s, to regulate the 
pressure. The rod 7 is guided vertically upward and downward 
by passing through the tubular guides and stuffing-box formed 
at ¢¢, on the curved exit passage 7, which leads to a chimney 
and conveys away the gaseous products escaping from the con- 
