AN IMPROVED CONSTRUCTION OF FURNACE FOR RE-HEATING STEEL, PREPARATORY TO THE HARDENING, TEMPERING, OR ANNEALING PROCESS
Year: 1859

page_text: PROVISIONAL SPECIFICATION left by Alfred Vincent Newton at the
Office of the Commissioners of Patents, with his Petition, on the 28th
March 1859. A communication from abroad by Perry Green Gardiner,
of New York.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Mechanical Draughtsman, do hereby declare tho.
nature of the said Invention for "AN IMPROVED CONSTRUCTION OF FURNACE FOR
RE-HEATING STEEL, PREPARATORY TO THE HARDENING, TEMPERING, OR ANNEALING
PROCESS," to be as follows:-
The object and nature of this Invention consists in so arranging the furnace
as to cause the flame and heat to act upon a closed oven or chamber or
chambers, in which the metal to be operated upon is placed, in such manner
as to distribute the heat, under, above, and on the back of the oven or
chambers, and to communicate a powerful and steady heat to the interior of
the oven or chambers, while such interior and its contents have no communi-
cation with the flame or gases of combustion, and as little as possible with the
external atmosphere.
The reheating of steel for the purposes of hardening or tempering, or
annealing, has heretofore been effected in reverberatory furnaces, the flame and
heated gases coming in direct contact with the metal. In some instances ovens.
have been constructed in which the flame and gases passed under the floor of
the heating oven (so as not to come in contact at first with the metal itself);
and then passed above the metal, but in the same chamber with the metal.
The difficulty with all such methods of re-heating stool arises from the fact that

page_text: the steel being exposed to the flame and atmosphero of the furnace contracts
impurities that impair its qualities, the carbon in the steel becoming oxidated
by the oxygen of the atmosphere, and from one part being more heated than
another, the steel loses its uniformity of texture.
In order to obtain a better result in the re-heating of steel, the Inventor
employs an improved construction of furnace, the general shape of which is
rectangular and oblong. The brick walls and structure are continued above
the body of the stack in reduced size for the exit flue and damper. Iron
clamps with tapped rods and nuts are provided for securing the brickwork
together; there are two doors to the heating oven (which is divided into two
chambers by partition wall). A blast pipe communicating with the fire-
place is employed, but is used only occasionally when tho fire is first started.
There is another air tube which runs along at the bottom and back of the
vertical flues. The grate bars of the furnace and the floor of the heating
ovens are placed nearly upon the same plane, the oven floor being a little
lower than the grate bars, the grate bars and chamber for fuel being at one
end of the furnace, extending across the body of the furnace and parallel with
the oven. The door of the fire-place is in the back of the furnace upon the
side opposite to that on which the doors of the oven are placed. Behind the
bridge wall of the fire-place, which extends along the whole length of the fire-
chamber, are four vertical flues through which all the beat and flame from
the fire passes, the bridge wall being lower than the sides of the flues in order
to leave horizontal openings into the flues. The four vertical flues are con-
tinued downward until they are at a point sufficiently below the floor of the
oven, when they are turned at right angles, and run horizontally until they
reach beyond the floors of the heating oven. The floor of this oven is con-
structed of fire tiles. The sides and top of the oven are arched and built of
fire brick; the flues after passing under the oven ascend vertically, and the
flame and beat are thus carried into extended horizontal flues or spaces at
right angles to each other. By means of these spaces or extended fire flues,
the upper portions of the back and of the side of the oven farthest from the
fire chamber are exposed to the heat like the other parts. The heat and
flame are then carried up vertically to the level of the exterior of the roof of
the oven; it is then continued from the front to the back of the roof of tho
oven by dividing walls extending part way across, so that the heat and flame
are conducted in a circuitous direction back and forth on the roof of the oven
before ascending into the exit flue or chimney. The flue at the top is pro-
vided with a sliding damper to close or open it; openings are constructed in
the walls of the furnace for the admission of air to keep the oxterior of tho

page_text: furnace from being too highly heated. At the foot of the vertical descending
flues a metal air tube is placed which extends along the whole length of the
grate bars on the opposite side of the bridge wall. Where the tube crosses
the descending flues, it is pierced with many holes, so as to supply the external
air freely to the smoke and flame and gases of the fuel.
The steel to be reheated is placed within the ovens upon fire bricks,
trestles, or supports slightly elevated from the floor; the door should be tightly
closed, and kept tight during the operation. This arrangement of the oven
into two distinct parts is convenient for having a constant supply of the
properly heated metal.
The ovens thus constructed and heated, if kept closed, will retain their heat
a very long time, and the heat can be graduated to the degree desired with
ease and accuracy. The blast through the air tube will rarely be required, .
and only at the first starting of the fires. After the steel has been heated to
the desired degree, it is to be submitted to a process of hardening, tempering,
or annealing.