IMPROVEMENTS IN HOT BLAST OVENS
Year: 1864

page_text: LETTERS PATENT to Henry Everard Clifton, of the City and County of
Saint Louis, State of Missouri and United States of America, for the
Invention of "IMPROVEMENTS IN HOT BLAST OVENS."
Sealed the 23rd August 1864, and dated the 10th March 1864.
PROVISIONAL SPECIFICATION left by the said Henry Everard Clifton
at the Office of the Commissioners of Patents, with his Petition, on the
10th March 1864.
I, HENRY EVERARD CLIFTON, of the City and County of Saint Louis,
State of Missouri and United States of America, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN HOT BLAST OVENS," to be
as follows:-
The object of this Invention is to effect great economy in the construction
and working of hot blast ovens. To this end the air-heating pipes are formed
in such manner that the air shall traverse over heating surfaces nearly twice
the length of the pipes before it escapes from the oven. These heating surfaces
I form, by preference, of refractory clay, as they will then admit of exposure to
irregular and excessive heat without suffering like metal from contraction and
expansion. The cylindrical heating pipes connect severally with their supply
and discharge pipes, and are thus made independent of each other so as to
allow of any one of the series being thrown out of use. The heating surfaces

page_text: consist of one pipe or cylinder placed within the other. The outer diameter
of the inner pipe or cylinder (the front end of which extends beyond the outer
cylinder) is somewhat less than the interior diameter of the outer cylinder in
order to afford space for the passage of air all around, and at suitable
intervals apart the inner pipe is furnished on its periphery with rings which
serve to break the current of air flowing between the pipes, and thus ensure
its particles being equally heated, and producing a uniformity of temperature
in the blast. These rings or stops may fit into the bore of the outer cylinder
with tolerable accuracy, channels or passages being formed in them at irregular
points to allow the air to pass. To the outer ends of these two cylinders a
metal cap or head-piece is attached by bolts or equivalent contrivances, and
provided with a supply pipe for the admission of cold air which is conducted
to the interior of the inner cylinder, and with a discharge pipe which com-
municates with the spaces between the two cylinders where the air is heated.
The cold air-supply pipe communicates with the inner pipes or cylinders (for
the admission of air thereto) by means of a flexible tube which will allow of
any one head-piece being moved on one side should the heating surfaces in
connection therewith require to be removed for repair. The hot air discharge
pipe must be connected with the main discharge or blast pipe in such a manner
that it will be capable of expanding longitudinally without the risk of deranging
the parts by the expansion of the metal. A valve is provided for each of these
pipes for cutting off connection when required with the main discharge or blast
pipe. At the rear ends of the heating pipes or cylinders the oven wall is pro-
vided with circular openings somewhat larger in diameter than the pipes to allow
of their withdrawal for repairs should such an operation be necessary; these
openings in the oven wall are closed by doors mounted on hinges. In order
to clean the outside of these heating pipes or cylinders a semicircular rake or
scraper with a long handle is employed, and may be introduced through the
openings at the rear end of the oven.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed 3
by the said Henry Everard Clifton in the Great Seal Patent Office
on the 10th September 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
EVERARD CLIFTON, of the City and County of Saint Louis, State of Missouri
and United States of America, send greeting.
38

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of March, in the year of our Lord One
thousand eight hundred and sixty-four, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Henry Everard Clifton, Her special license that I, the said Henry
Everard Clifton, my executors, administrators, and assigns, or such others
as I, the said Henry Everard Clifton, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time
and at all times thereafter 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 HOT BLAST OVENS," upon the condition (amongst
others) that I, the said Henry Everard Clifton, by an instrument in
writing under my hand and seal, 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 Henry Everard Clifton, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):
:-
It is well known that the metallic devices, viz., the heating pipes with their
necessary rings, joints, and connections as ordinarily constructed and arranged
within hot blast ovens are very liable to material damage by cracking and
giving way under irregular and excessive heat, that at best they cannot with-
stand the very high temperature so desirable in hot blasts, and also that the
unequal expansion and contraction of the metal is exceedingly liable to open
and disarrange the joints of the pipes, which being within the oven cannot by
any possibility be repaired or replaced without stopping the operation of the
hot blast for a considerable length of time, thereby involving vast expense
and
much labor.
The objects of this Invention are to overcome the aforesaid and other
difficulties, to effect great economy in the construction and operation of hot
blast ovens, to increase the efficiency and durability thereof, and at the same
time to produce a simple furnace for heating air, which without damage or
injury to the heating devices may impart to the blast a much higher degree of
beat than can be obtained by means of metallic devices now in common use for

page_text: These I
like purposes. To this end I employ refractory clay or other equivalent
earthen substance as the material for constructing the pipes or heating
cylinders used as air passages or receptacles within hot blast ovens.
construct and arrange in a novel manner, employing annular rings or stops
for breaking the current of the air, and facilitating the heating of the same.
I also employ certain detachable connecting devices and flexible connections
for facilitating the removal of a defective heating cylinder from the oven; and
I further construct the rear wall of the oven so that the heating cylinders may
be cleaned while in the oven, or readily removed therefrom without disturbing
the brickwork.
-
In reference to the accompanying Drawings, Fig. 1 is a front elevation of
the oven, shewing the external connections, pipes, and joints; Fig. 2 is a
partial back view of the oven in transverse vertical section, shewing the
adjustment of the heating cylinders within the oven; Fig. 3 shews a com-
pound heating cylinder detached, the outer part being in section to exhibit
the arrangement of the annular rings or stops and the adjustment of the inner
heating cylinders; Fig. 4 is a longitudinal cross section of the inner and outer
heating cylinders, shewing their connections with the external pipes; Fig. 5
is a sectional view of the main discharge pipe intended to represent the
arrangement of valves that may be employed therein; Figures 6 and 7
represent a device that may be employed for cleaning the cylinders.
of
A, A¹, A", represent the walls of the oven, which may be of suitable
masonry lined with fire bricks, as in the ordinary manner of constructing
devices for like purposes, and the said oven may be heated as is usual by
means of the waste heat of the furnace and suitable fuel. B, C, represent the
heating cylinders, which are formed of refractory clay or other suitable equi-
valent earthen material, and arranged one within the other substantially in
the manner represented in Figures 3 and 4, the extreme diameters of the
inner cylinders C being somewhat less than the interior diameters of the
cylinders B in order to afford proper spaces between them for the
passage
air, and for a like purpose the rear ends of the cylinders C, which in all cases
will be open when arranged for use, will be so adjusted as to afford suitable
spaces as e, seen clearly in Fig. 4. The front ends of the cylinder C extend
beyond those of the outer cylinders B in order to facilitate the arrangement
of devices for supplying cold and conducting hot air, as herein-after set forth.
The said cylinders C are provided at suitable intervals with annular rings or
stops d of the same material as, and moulded either separate from or together
with the cylinders. These rings or stops d fit with tolerable accuracy the
bores of the cylinders B, but a close or perfect fit is not essential, and there is

page_text: formed in them at irregular points channels or passages g. By this arrange-
ment the progress of the air which may be undergoing the process of being
heated will be obstructed and delayed, and its current broken in such
manner that all its particles may be equally heated, thereby securing to the
blast greater unformity and a higher degree of temperature than can be
attained by other known methods. The front ends of the cylinders, B, C,
extend through and are supported by the front wall A¹ of the oven, and are
secured therein in such manner as to be easily removable, and also to prevent
the heat from escaping from the oven around them, their rear ends may be
sustained by means of suitable standards extending from the base of the oven
or projections from the rear wall A".
In the rear wall A" opposite to the rear ends of the cylinders B are formed
openings, see Fig. 2, of somewhat larger diameter than the cylinders; these
openings are covered with suitable hinged doors h, by opening which the cleaner k
or an equivalent device may be inserted in the oven for the purpose of removing
any injurious deposits upon the cylinders B, or the said cylinders may be
removed from the oven when necessary. Suitable caps must be provided to
close the openings in the front wall A¹ that may be occasioned by the tem-
porary removal of any of the heating cylinders for such time as may be
necessary for repairing or renewing said cylinders so removed. m represents
the detachable connecting devices, through the medium of which cold air may
be admitted to and hot air conducted from the heating cylinders. These
connections m are provided with supply pipes n communicating with the
interior of the inner cylinder c and with discharge pipes p communicating with
the interior spaces fof the cylinders B, as seen clearly in Fig. 4. The supply
pipes n may be made to extend through the heads of the connections m into
the cylinders C, or equivalent tubes extending inwardly, and adapted to fit
nicely; the bores of the cylinders C may be cast with and made to form a part
of the connections m, as shewn in Fig. 4. The pipes n, p, may be made in
sections or joints provided with flanges, and secured together by means of
bolts or otherwise in such manner as to be readily disjointed when necessary
for repairs. The said connections may be made with flanges (see Figures 1
and 4), and they will be secured to the front ends of the cylinders B by
means of bolts and nuts or other efficient means in such manner as to ensure
good and substantial joints, and at the same time to be readily detachable.
The pipes n have communication with the cold air cylinders by means of
the short pipes, which are made of india-rubber or other suitable flexible
material, so that the connections m, when detached from the cylinders B, and
disjointed from the pipes p, may be moved aside sufficiently to allow the

page_text: heating cylinders to be withdrawn from the front of the oven without dis-
arranging any of the joints or connections of the cold air pipes. The several
pipes p communicate with the main discharge pipe 7 (see Fig. 1), and their
joints and connections therewith may be of such character as to allow the said
pipes to work longitudinally in order to compensate for the necessary expansion
and contraction of metal of which they may be formed, and thus preserve
intact the joints, and increase the durability of the discharge pipes.
All the openings leading from the main discharge piper to the pipes p.
and thence to the cylinders B will be provided with suitable valves (see t,
Fig. 5) constructed and arranged to operate in such manner as to prevent the
gases of the furnace from entering the oven, and also to prevent the hot air
from escaping during the operation of the blast through the openings com-
municating with those particular cylinders that may be temporarily removed
from the oven. The cleaner k, Fig. 7, is formed with two prongs k¹, which
are adapted to fit closely the exterior surfaces of the cylinders B, so that by
being inserted through the openings in the rear wall A" of the oven, and
properly actuated, all foreign matter or deposits may be readily and rapidly
removed from the cylinders even during the operation of the hot blast.
Suitable valves will be required to control and regulate the admission of cold
air. The number and capacity of the heating cylinders may be varied in
accordance with the size of the oven and the nature of the blast required,
and they may be removed from the front or rear of the oven as may be found
most convenient.
.
The operation of this Invention will be readily and fully understood by
persons familiar with other devices for like purposes without further expla-
nation. It will now be clearly seen that each particular set of heating
cylinders is independent of all the others, and in case any one of them should
prove defective, or from any cause require repair or renewal, the same may
be removed from the oven and be replaced therein again without interrupting
the operation of the hot blast. The heating cylinders being formed of suitable
clay are capable of withstanding a much higher temperature without injury
than metallic devices in ordinary use. For like purposes they will be made
of a much greater thickness than the ordinary iron pipes, so that they will
retain heat longer, and, as I believe, will conduct and impart heat to the air
in a more regular and uniform manner; the hot blast is therefore much
improved, and at the same time the cost of construction will be materially
diminished. All the joints and connections in my improvement being outside
the oven, and therefore not exposed to intense heat therein, may be of suitable
wrought or cast metal, cast iron being preferred; they are also arranged in

page_text: such manner that any fault or imperfection may be at once seen and repaired
without difficulty or loss of time.
I do not wish to confine myself to the precise construction and arrangement
of the connections, pipes, and joints outside the oven, as it is quite obvious
the same may be varied to some extent without departing from the spirit of
my Invention; neither do I confine myself to the use of clay or earthen
material for the construction of the heating cylinders, as it is plain that
metallic devices constructed and arranged as herein described, with reference
to the cleaning and removing of the cylinders, and to the detachable con-
nections upon the outside of the oven, constitute a decided improvement which
is clearly embraced in the subject matter of my Invention. The connections m
may be secured in various ways, but I prefer that they shall be attached
directly to the front ends of the cylinders B, as herein-before described, the
most reliable and perfect joints being thereby effected.
Having now set forth the nature of my Invention of "Improvements in
Hot Blast Ovens," and explained the manner of carrying the same into
effect, I wish it to be understood that under the above in part recited Letters
Patent, I claim,—
First, the construction and arrangement of beating cylinders, as and for
the purposes set forth.
Second, in combination with the cylinders B, C, the employment of detach-
able connecting devices arranged outside the oven for admitting cold air to
and conducting hot air from the heating cylinders, substantially as herein
described and represented.
Third, the use of the flexible pipes in combination with the pipes n and
cylinder or pipes as and for the purposes named.
Fourth, constructing the rear wall of the oven with suitable openings through
the medium of which the heating cylinders may be removed or cleaned, as
herein specified.
In witness whereof, I, the said Henry Everard Clifton, have hereunto
set my-hand and seal, the Twenty-fourth day of August, in the year of
our Lord One thousand eight hundred and sixty-four.
HENRY EVERARD CLIFTON. (L.S.)
HENRY EVERARD CLIFTON. (L.S.)