Improvements in Sheet-metal Annealing Furnaces.
Year: 1889

page_text: Date of Application, 9th July, 1889
Complete Specification Left, 21st Mar., 1890-Accepted, 26th Apr.,
1890
PROVISIONAL SPECIFICATION.
Improvements in Sheet-metal Annealing Furnaces.
We EVAN JAMES FRANCIS and CHARLES BANFIELD, both of Leechburgh in the
County of Armstrong and State of Pennsylvania, United States of America,
Inventors, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to provide improvements in sheet heating furnaces
by which the heat is permitted to heat the sheets to be annealed very uniformly.
The invention consists in a bottom for the heating chambers of sheet heating
furnaces, formed of segregated masses, broken pieces, or fragments of non-
combustible material having interstitial passages, and presenting a broken or uneven
surface.
It is necessary to have a bottom made of some material that will allow the heat
to pass freely under the sheets in order to heat them uniformly.
The material at present employed is generally coke which is broken into small
pieces and spread over the bottom of the furnace to a depth of about six inches, and
presents a broken or uneven surface which allows the heat to pass readily under
the sheets, thus furnishing a very even heat. There are certain objections to this.
According to our invention the sheet heating furnace is provided with a fire
place connecting with the space in which the sheets to be heated for the rolling
mill are placed. The space connects with the chimney and the bottom of the said
space is formed by a non-combustible material placed on the bottom plate preferably
made of metal and having its supports in the sides and the end of the furnace and in
the bridge wall. At the front end of the furnace is formed an opening for the intro-
duction of the sheets to be heated, into the space and which also serves for the renewal
of the bottom whenever necessary.
The non-combustible material forming the bottom of the space may be broken pieces
or fragments of cinder or slag, or any other oxide of iron, or the said material may be
asbestos, soap-stone, etc. The non-combustible substances described furnish a clean
and remarkably cheap and durable bottom, and as the said substances will not burn
away their durability is unlimited, and as they do not contain any heat in themselves
they do not get hotter than the rest of the furnace, and consequently the bottom sheets
to be heated which are held in the space are heated to the same degree as the top
sheets. The segregated character of these pieces or fragments causes interstitial
passages to be formed, through which the heated gases are free to pass, and the upper
side of the bed presents a broken or uneven surface. The pile of sheets therefore will
as above stated be heated to the same degree at the bottom as at the top. The bottom
does not furnish any dust, ashes or sulphur, and hence the sheets to be heated are not
marked or spotted and no not stick together. A bottom made as described will last
a long time, thus saving a great expense to the manufacturer and labor for the
workman.
COMPLETE SPECIFICATION.
· Improvements in Sheet-metal Annealing Furnaces.
Wė, EVAN JAMES FRANCIS and CHARLES BANFIELD both of Leechburgh in the
County of Armstrong and State of Pennsylvania, United States of America, Inventors,
Price 8d1

page_text: 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-
The object of this invention is to provide improvements in sheet heating furnaces by
which the heat is permitted to heat the sheets to be annealed very uniformly.
The Invention consists in a bottom for the heating chambers of sheet heating
furnaces, formed of segregated masses, broken pieces or fragments of non-combustible
material having interstitial passages and presenting a broken or uneven surface, as
will be hereinafter fully described and claimed.
Reference is to be had to the accompanying drawing, forming part of this specifica-
tion, in which the figure illustrates a sectional side elevation of a sheet heating furnace
provided with our improvements.
In heating sheets in sheet heating furnaces, it is necessary to have a bottom made
of some material that will allow the heat to pass freely under the sheets in order to
heat them uniformly. The material at present employed is generally coke made from
coal. This material is broken up into small pieces and spread over the bottom of the
furnace to a depth of about six inches and presents a broken or uneven surface which
allows the heat to pass readily under the sheets thus furnishing a very even heat.
The coke, however on account of the great heat in itself, causes the bottom of the
heating chamber to become hotter than the rest thereof and consequently the bottom
sheets become too hot, thereby causing spoiling of the sheets. Besides this, the coke
soon burns away and only leaves a residue which has to be removed frequently and
the bottom has to be renewed. Unless extreme care is taken, the residue unites with
the sulphur and adheres to the sheets so as to cause them to become marked and
spotted and frequently causes the several sheets to stick together, thereby spoiling
said sheets which have to be thrown away. The daily and almost hourly renewal of
the bottom entails a great expense upon the manufacturer besides causing a great
amount of extra labor for the workinen. With our improvement, presently to be
described, the difficulties above mentioned are overcome.
The sheet heating furnace A, of any approved construction, is provided with a fire-
place B connecting with the space Cin which the sheets to be heated for the rolling mill
are placed in any suitable manner. The space connects with the chimney D and the
bottom of the said space C is formed by a non-combustible material F placed on
the bottom plate E preferably made of metal and having its supports in the sides and
the end of the furnace A and in the bridge wall G. At the front end of the
furnace A is formed an opening H for the introduction of the sheets to be heated into
the space and which also serves for the renewal of the bottom F whenever
necessary. The non-combustible material F forming the bottom of the space C may
be broken pieces or fragments of cinder or slag or any other oxide of iron or the said
material may be asbestos, soapstone, etc. The non-combustible substances described
furnish a clean and remarkably cheap and durable bottom and as the said substances
will not burn away, their durability is unlimited and as they do not contain any heat
in themselves they do not get hotter than the rest of the furnace and consequently
the bottom sheets to be heated which are held in the space Care beated to the same
degree as the top sheets. The segregated character of these pieces or fragments
causes interstitial passages to be formed, through which the heated gases are free to
*pass and the upper side of the bed presents a broken or uneven surface. The pile of
sheets therefore, will, as above stated, be heated to the same degree at the bottom as
at the top. The bottom does not furnish any dust, ashes, or sulphur, and hence the
sheets to be heated are not marked or spotted and do not stick together. A bottom
made as described will last a long time, thus saving a great expense to the manu-
facturer and labor for the workman.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is ;
A bottom for heating furnaces formed of segregated masses broken pieces or

page_text: fragments of non-combustible material having interstitial passages and presenting a
broken or uneven surface, substantially as set forth.
Dated this 21st day of March 1890.
E. J. FRANCIS.
C. BANFIELD.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.