IMPROVEMENTS IN REGENERATOR FURNACES
Year: 1874

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton.
Buildings, Chancery Lane, in the County of Middlesex, for the
Invention of." IMPROVEMENTS IN REGENERATOR FURNACES."-A com-.
munication from abroad by Morrison Foster, of Alleghenny City,
PROVISIONAL SPECIFICATION left by the said Charles Denton Abeļ*
at the Office of the Commissioners of Patents, with his Petition,
on the 16th July 1874.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN REGENERATOR FURNACES,"
to be as follows :—
This Invention relates to that class of regenerator furnaces in which
the products of combustion on their way to the chimney are utilised to
heat either the incoming air or gaseous fuel used, or both the air and

page_text: the fuel, and is more especially adapted to that class of regenerators
wherein tubes or tubular passages permit the products of combustion to
escape in one direction to the chimney, while the air and gaseous fuel, or
either, is passing to the furnace by passages surrounding the said tubes,
the heat being continuously absorbed by and taken up from opposite
surfaces; but it can be used with good effect in regenerators where the
heat is imparted to and taken up from the same surface, and the
operation of which may be termed intermittent.
Regenerator furnaces as a rule are used in the manufacture of steel
where high temperatures are required, and the products of combustion
escape from the hearth at such a high temperature as to affect injuriously
the tubes or brickwork of which the regenerator is composed. The
general form adopted in building furnaces of this class is such that the
hearth and regenerating chamber are closely connected, so that no time
is permitted for loss of heat by the products of combustion in passing
from the hearth to the regenerator which is generally situated just
beneath the hearth. As a consequence of this construction great
difficulty is encountered in constructing regenerator furnaces, so that
the portion of the tubes upon which the products of combustion first
strike shall last; the burning out of the tubes and the breaking due to
expansion and contraction being a constant cause of expense and
annoyance.
.
The object of this Invention is to so modify the construction of the
regenerator that this difficulty shall be overcome, and greater durability
of and more uniform distribution of heat through the regenerators shall
be obtained. For this purpose according to this Invention a checker-
work or reticulated barrier is placed in such relation to the mouth of the
regenerating chamber that it shall break the first force of the products
of combustion, and protect the regenerator from the intense heat of the
products of combustion. Such reticulated barrier may be constructed
either by piling up bricks of fire-clay or other suitable refractory
material in such a manner as to leave interstices between them through
which the products of combustion pass, or they may be of fire-clay
slabs or blocks having apertures formed in them; the barrier is con-
structed in a chamber formed between the mouth of the regenerator
and the downtake or flue, through which the products of combustion
escape from the hearth of the furnace, so that the products of combustion
in passing from such flue through the checkerwork or reticulated barrier

page_text: give off a portion of their heat to the same before entering the
regenerator. The apertures of the said barrier are by preference made
to increase in size or number from top to bottom or other line of retreat
of the flame, so that the products of combustion are more uniformly
distributed to the regenerator.
The barrier in absorbing a portion of the heat of the products of
combustion also acts as a storehouse of heat which is given off at such
times as it may be desirable to stop the furnace, keeping the temperature
of the regenerator at such a point that but little time is required to
raise the furnace again to working heat. It will be evident that the
said barrier may also be employed to operate in like manner in
combination with hot blast stoves.
:
The Invention consists further in providing stoppered apertures in
the wall of the furnace directly opposite that side of the barrier through
which the products of combustion enter it, through which apertures
external air may be allowed to pass in and mix with the products of
combustion so as to reduce the temperature thereof before entering the
barrier when required.
According to another part of the Invention such stoppered apertures
for the admission of air are also used in combination with regenerator
furnaces that are not provided with the before-described reticulated
barrier, for the purpose of controlling the temperature of the products of
combustion in the downtake or flue leading from the hearth to the
regenerator. A series of such stoppered apertures being provided in the
walls of the downtake in such positions that the temperature of the
products of combustion escaping from the hearth may be reduced at
any desired point before reaching the regenerator, by the admission of
air through one or more of the apertures. Such apertures may also.
serve as sight holes by which the condition of the before-described
barrier or of the regenerator may be examined from time to time.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Denton Abel in the Great Seal Patent
Office on the 14th January 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane, in
the County of Middlesex, send greeting.
-
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of July, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
eighth year of Her reign; did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles Denton Abel, Her special
license, that I, the said Charles Denton Abel, my executors, adminis-
strators, and assigns, or such others as I, the said Charles Denton
Abel, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN REGENERATOR FURNACES," a communication to
me from abroad by Morrison Foster, of Alleghenny City, State of
Pennsylvania, United States of America, upon the condition (amongst
others) that I, the said Charles Denton Abel, my executors or admini-
strators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Charles Denton Abel, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, reference being had to the
accompanying Sheet of Drawings and to the figures and letters marked
thereon, that is to say :-
This Invention relates to that class of regenerator furnaces in which
the products of combustion on their way to the chimney are utilised to

page_text: lieat either the incoming air or gaseous fuel used, or both the air and
the fuel, and is more especially adapted to that class of regenerators
wherein tubes or tubular passages permit the products of combustion to
cscape in one direction to the chimney, while the air and gaseous fuel, or
cither, is passing to the furnace by passages surrounding the said tubes,
the heat being continuously absorbed by and taken up from opposite
surfaces; but it can be used with good effect in regenerators where the
heat is imparted to and taken up from the same surface, and the
operation of which may be termed intermittent.
Regenerator furnaces as a rule are used in the manufacture of steel
where high temperatures are required, and the products of combustion
escape from the hearth at such a high temperature as to effect injuriously
the tubes or brickwork of which the regenerator is composed. The
general form adopted in building furnaces of this class is such that the
heartli and regenerating chamber are closely connected, so that no time
is permitted for loss of heat by the products of combustion in passing
from the hearth to the regenerator - which is. generally situated just
beneath the hearth. As a consequence of this construction great
difficulty is encountered in constructing regenerator furnaces, so that the
portion of the tubes upon which the products of combustion first strike
shall last; the burning out of the tubes and the breaking due to
expansion and contraction being a constant cause of expense and
annoyance.
The object of this Invention is to so modify the construction of the
regenerator that this difficulty shall be overcome, and greater durability
of and more uniform distribution of heat through the regenerators shall
be obtained. For this purpose according to this Invention a checker-
work or reticulated barrier is placed in such relation to the mouth of
the regenerating chamber, that it shall break the first force of the
products of combustion and protect the regenerator from the intense
heat of the products of combustion. Such reticulated barrier may be
constructed either by piling up bricks of fire-clay or other suitablo
refractory material in such a manner as to leave interstices between
them through which the products of combustion pass, or they may be of
fire-clay slabs or blocks having apertures formed in them; the barrier is
constructed in a chamber formed between the mouth of the regenerator
and the downtake or flue through which the products of combustion
escape from the, hearth of the furnace, so that the products of com-

page_text: bustion in passing from such flue through the checkerwork or reticulated
barrier give off a portion of their heat to the same before entering the
regenerator. The apertures of the said barrier are by preference made
to increase in size or number from top to bottom, or other line of retreat
of the flame, so that the products of combustion are more uniformly
distributed to the regenerator.
•
The barrier in absorbing a portion of the heat of the products of
combustion also acts as a storehouse of heat which is given off at such
times as it may be desirable to stop the furnace, keeping the temperature
of the regenerator at such a point that but little time is required to
raise the furnace again to working heat. It will be evident that the
said barrier may also be employed to operate in like manner in
combination with hot blast stoves.
The Invention consists further in providing stoppered apertures in the
wall of the furnace directly opposite that side of the barrier through
which the products of combustion enter it, through which apertures
external air may be allowed to pass in and mix with the products of
combustion so as to reduce the temperature thereof before entering the
barrier when required.
1
According to another part of the Invention such stoppered apertures:
for the admission of air are also used in combination with regenerator
furnaces that are not provided with the before-described reticulated
barrier, for the purpose of controlling the temperature of the products of
combustion in the downtake or flue leading from the hearth to the
regenerator. A series of such stoppered apertures being provided in the
walls of the downtake in such positions that the temperature of the
products of combustion escaping from the hearth may be reduced at
any desired point before reaching the regenerator by the admission of
air through one or more of the apertures. Such apertures may also
serve as sight holes by which the condition of the before-described
barrier or of the regenerator may be examined from time to time.
.
regenerator furnace with reticulated barrier; Fig. 2 shews a sectional
perspective view; Fig. 3 shows a transverse section on line y, y, Fig. 1. 3

page_text: Fig. 4 shows a longitudinal section of the before-described regenerative
furnace without the reticulated barrier but with air holes; and Fig. 5
shews an end view of the furnace.
In Figs. 1 to 3, A represents the hearth to which the gaseous fuel and
air are delivered through the passages a, a', the products of combustion.
escaping through the passage or throat b; B represents the tubes of the
regenerators.
In the majority of regenerative furnaces of the continuous class;
these tubes are composed of either fire-clay or iron, and conduct the
waste products from the regenerator to the chimney, the air and gas on
their way to the furnace being heated by passing around the said tubes.
through the chambers C, which connect with the furnace by means of
the passages a, a¹. D is a chamber into which the products of com-.
bustion are conducted from the hearth. This chamber may be
considered in reality nothing more than an enlargement of the flue
through which the waste products pass to the regenerator. Within this.
chamber or enlargement of the flue a barrier E is erected in the
following manner:--As illustrated in the Drawing it is built from
bricks which may be fire-clay or any other refractory, material, and is of
regular form constructed by piling the bricks in such a manner as to
allow of a series of passages increasing in size in this case from top to
bottom, and it is located directly in front of the tubes B or the mouth of
the regenerator.
Instead of using bricks of uniform size and constructing this barrier
with a regular checkered appearance as here presented, the object will be
accomplished if any form of brick or block is used which will permit of
passages between them; or of the construction of passages increasing
either in number or size from top to bottom, or in the direction in which
the flame is moving across the first range of them for the passage of the:
products of combustion. Against this barrier the intensely heated waste
gases first strike.
The object in increasing the diameter of the openings is to cause a
more uniform distribution of the gases, a smaller volume passing through
where the flame first impinges on the barrier than at the distant points
where the temperature is lower, for the reason that the gases will be.
more highly heated at the first point than at the latter, and the pressure.
will also be greater. Directly opposite the barrier E in the face of the

page_text: imparted to the regenerator, and all waste heat of the products of
combustion utilized. But it is evident when we consider that even for
steel making from 3600° to 4000° Fahrenheit, is the highest heat
required on the hearth, and at the time the combustion takes
place the elements entering into the flame are raised 1200° Fahr. or
thereabouts, it is not necessary that the temperature of the regenerator
should exceed 2400° to 2800° Fahr. (provided the regenerator is of
sufficient capacity for the work expected of it); and if the temperature:
of the products of combustion passing from the hearth to the regenerator
are so controlled as to maintain the regenerator at or about that
temperature, the useful purposes of a regenerator will be attained and
the heats which have been heretofore so detrimental will be avoided.
The construction of regenerator furnaces heretofore employed is not
such that the temperature of the products of combustion passing to the
regenerator can be regulated, but must vary, according as a reducing,
neutral, or melting flame is used.
The object therefore of the second part of the present Invention is to
provide a means for controlling the temperature of the products of
combustion as herein-before stated.
In the Drawings referred to, A indicates the hearth of the furnace;
a, the flue for the admission of heated air; a¹, the flue for the admission
of heated gas; B, the downtake or flue leading to the regenerator;
C, the heating chamber through which the air and gas pass on their way
to the hearth; D, the hollow bricks or tubes of which the regenerator is
constructed, and through which the products of combustion pass on
their way to the chimney, and around which the incoming air and gas pass
to take up the heat. These are or may be all of the usual or any
approved construction. Through the outer wall of the downtake or
flues B a series of openings 6 for the admission of air to the downtake
to reduce the temperature of the products of combustion on their
passage from the hearth A. These openings may be partially or entirely.
closed at will by a series of plugs or other devices 6'. They may extend
the whole length of the downtake or so far up as is found by practice in
each case to be best. By this means the products of combustion coming.
from the hearth can be diluted at any point that may be desired, either.
in the upper portion near the throat or lower down at the points.
opposite the regenerator proper, as circumstances may dictate.

page_text: Third. The combination with the barrier E of the air inlets c,
substantially as and for the purpose described.
Fourth. The method of controlling the temperature of the products
of combustion in regenerator furnaces after their escape from the hearth
by the admission of air, substantially as specified.
Fifth. The use for the purpose referred to in the preceding claim of a
series of stoppered openings in the downtake flue of the furnace for the
admission of air, substantially as herein described.
In witness whereof, I, the said Charles Denton Abel, have here-
unto set my hand and seal, this Fourteenth day of January,
in the year of our Lord One thousand eight hundred and seventy-
five.