Improvements in and relating to Kilns, and Cupola and other Metallurgical Furnaces.
Year: 1893

page_text: Date of Application, 24th Oct., 1893-Accepted, 2nd Dec., 1893
COME ELE DIEUIFICATION.
Improvements in and relating to Kilns, and Cupola and other
Metallurgical Furnaces.
I, EDWARD JAMES BIRD, a citizen of the United States of America, residing
at Big Stone Gap, in the County of Wise, and State of Virginia, one of the United
States of America, Manufacturer, do hereby declare the nature of this invention,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to certain improvements in lime kilns, and cupola and
other metallurgical furnaces of that class in which the fuel and materials to be
reduced are placed in layers or scaffolds in the furnace and the combustion is urged
by a blast of air introduced into the lower part of the kiln or furnace.
In such kilns or furnaces the scaffolds or sections of fuel or limestone and ore,
tend to pack above the zone of reduction, and form an impenetrable bridge, which
prevents the passage of the products of combustion upward, through the stack,
thus retarding the combustion and reduction below, and materially interfering with
the operation of the kiln or furnace.
It is the object of my invention to obviate this difficulty, and this I accomplish
by means of an auxiliary draft tube, provided with suitable valves, in connection
with the flue or furnace, by which a direct draft from about the zone of reduction
may be established, so as to ensure a proper reduction temperature when the
scaffolds or sections pack and bridge the passage in the stack, until the superincum-
bent weight of the scaffolds or sections breaks down the obstruction, as the fuel
below is consumed and the material reduced.
The above-mentioned objects are attained by the means illustrated in the accom-
panying drawings, in which is represented a vertical sectional view of a lime kiln or
cupola furnace showing my invention applied thereto.
Referring to the drawings, the numeral 1 indicates a kiln or furnace of the
ordinary construction, 2, the hearth thereof, and 3 the tuyeres through which
the air blast is introduced. The line 4, 5, indicates the zone of reduction, and the
numeral 6 a tube leading outward from the kiln or furnace at about the said zone
of reduction. The said tube is carried upward and is bent inwardly, entering the
stack near its upper end, so that the products of combustion may be conducted into
the stack. The tube is also provided with a direct uptake 7, by which the products
of combustion may be discharged into the open air when desired.
Near the upper and lower ends the tube is provided with valves 8 and 9, by which
the draft from the furnace may be turned on and off, or directed into the open air
at will
The tube is also provided with relief valves, 10, and 11, which may be of any
suitable construction, but which in the present instance consist of hinged plates
opening outwardly, so as to blow open and permit the escape of generated gases in
case of explosion.
The object of carrying the upper end of the tube into the stack of the furnace, is
to utilize the hot products of combustion for heating the blast, or a steam boiler or
boilers, as is usual in this class of kilns or furnaces, the kiln or furnace being
provided with the usual conduits for conveying such products to the place of use.
As such construction is common to this class of kilns and furnaces, it is unnecessary
to illustrate or further describe it.
The operation of my invention will be readily understood in connection with the
above description and is as follows:
When the combustion and the consequent reduction in the kiln or furnace is
retarded by the packing of the material in the upper part thereof, the lower valve

page_text: of the auxiliary draft tube is opened, allowing the products of combustion at the
zone of reduction to pass off.
By opening or closing the upper valves, the products may be directed into the
upper stack, to serve as heating agents as before mentioned, or may be allowed to
pass directly into the open air, in case they are not necessary for such purposes.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a lime kiln or other furnace, the employment of an auxiliary draft tube
leading from about the zone of reduction for the purpose of establishing a direct
draft from about said zone.
2. The combination in a lime kiln or other furnace, of an auxiliary draft tube
leading outward from the zone of reduction and provided with a suitable controlling
valve, substantially as specified.
3. The combipation in a lime kiln or furnace, of an auxiliary draft tube, leading
from the zone of reduction to the upper part of the stack, and provided with
suitable controlling valves, substantially as and for the purposes specified.
4. The combination with the auxiliary draft tube leading from the zone of
reduction, of the relief valves adapted to be automatically blown open in case of
explosion, substantially as specified.
5. The combination with the auxiliary draft tube leading from the zone of reduc-
tion, of the uptake leading to the open air, and the valves, whereby the products of
combustion may be directed into the stack or the open air, substantially as set
forth.
Dated
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.