IMPROVEMENTS IN FURNACES FOR HEATING AIR, STEAK, AND OTHER ELASTIC FLUIDS
Year: 1863

page_text: LETTERS PATENT to Edward Alfred Cowper, of No. 354; Great George
Street, Westminster, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN FURNACES FOR HEATING AIR, STEAK, AND OTHER ELASTIC
FLUIDS."
Sealed the 22nd January 1864, and dated the 5th August 1863.
PROVISIONAL SPECIFICATION left by the said Edward Alfred Cowper'
at the Office of the Commissioners of Patents, with his Petition,
on the 5th August 1868.
I, EDWARD ALFRED COWPER, of No. 354, Great George Street, West-
minster, in the County of Middlesex, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN FURNACES FOR HEATING AIR, STEAM, AND
OTHER ELASTIC FLUIDS," to be as follows:-
My Invention relates to furnaces in which pipes are heated externally by.
means of a fire, whilst internally air, steam, or other elastic fluids are pumped
or forced through them, whereby such elastic fluids become heated. In'
furnaces hitherto employed for this purpose cast-iron pipes have invariably
been made use of, and in consequence no very high degree of temperature has-

page_text: been attainable on account of the melting or injury to the pipes that has
occurred whenever it has been attempted to raise the temperature of the elastic
fluid much above 700 degrees Fahrenheit.
In the Specification to certain Letters Patent granted to me, and bearing date
the 19th May 1857, (No. 1404), I mentioned that "pipes of fire-clay cannot
be employed in the ordinary furnaces, as they would leak or crack, and the air
would escape." Now my present Invention consists in making such pipes of
fire-clay or other refractory material capable of being employed for the above
purpose, by the following means:-I line such pipes of fire-clay or other refrac-
tory material with a coating of glaze, litharge, flux, porcelain, or other fine clay,
or other suitable close-grain substance that will not permit the passage of the
elastic fluid through the sides of the pipes. I prefer the refractory material for
the pipes to be fire-clay, blacklead, or materials such as are used for crucibles.
In some cases I incorporate a portion of the above-named air-tight materials
with the fire-clay, so as to render the pipes as nearly as possible air-tight.
Furthermore in order to allow of the expansion and contraction of the pipes
of refractory materials without the connections or joints leaking, or being
broken, or the pipes: becoming cracked, I cause the extremities of such pipes
to pass through the brickwork of the furnace, and there connect them by
means of connecting pipes in the following manner: I arrange strong'iron
bars, girders, or beams, such as "buck staves," outside the furnace, well tied
together by bars or rods above and below. or beyond the furnace, and against,
these, as points of resistance, I arrange screws or equivalent means to force
the connecting pipes against the pipes of refractory material, and between such
screws and the connecting pipes I place springs or suitable elastic materials,
whereby whilst exerting the requisite. pressure upon the connecting pipes to
insure perfect joints the pipes of refractory material are nevertheless at liberty
to expand and contract freely. Or in place of the screws and springs, I employ
bell-crank levers with long arms weighted to any required degree, or attached
to springs of any required degree of tension, and short arms.pressing against
the connecting. pipes so as to exert the requisite pressure for maintaining a
good joint, and yet, to yield to the expansion and contraction of the pipes;
or I attach the connecting pipes to the pipes of refractory material... by
means of screw bolts, fixed to lugs formed on the latter, with or without an
elastic-medium between,the pressing surfaces. The connecting pipes may
with advantage be, made curved and of wrought iron, so as to yield to a
slight extent should the pipes, of refractory: material expand. or contract
uneanelle- T

page_text: By the foregoing arrangement I am enabled to get at the joints of the
pipes with the greatest facility, and to make good any leaky joints that may
possibly occur, without either cooling down the stove or stopping the use of
the same except for a very short space of time.
In combination with the above described arrangement I sometimes form a
portion of the heating pipes. of cast iron, of the ordinary construction, and
cause the elastic fluid to pass. first through these on entering the furnace and
afterwards through the pipes of refractory material, the iron pipes should in
this case be placed in the coolest part of the furnace so as not to become
heated beyond their powers of resistance.
The arrangement of the pipes as regards their position in the furnace may
be variously modified; "thus they may be horizontal, vertical, or inclined, but
they should be so placed that the heated currents from the fire passing over
their outer surfaces should be broken up, and brought into good contact with
the same; but in most cases the heat from the fire can be best arranged to
enter from one end or the bottom of the furnace, whilst the air, steam, or other
elastic fluid enters the pipes from the other end or the top, and passes back-
wards and forwards through the same, and finally issues at the opposite end
of the furnace to that at which the heat escapes, in a manner well, understood
and forming no part of my present Invention. .
Furthermore I provide the pipes. with plates or pieces of refractory
material placed inside to break up or divide the streams of elastic fluid as they
pass through, so that they may the more thoroughly become heated. These
furnaces can be advantageously heated by the combustion of gas obtained
from such ccke ovens as those patented by Charles William Siemens, on the
18th April 1863, (No. 972), or from such gas producers as those patented
by Charles William Siemens and Frederick Siemens, on the 22nd January
1861, (No. 167), or they can be advantageously, heated by gas from the top
of blast furnaces or from common coke ovens, or by a common fire, or by heat
produced in any other convenient manner.
:
The above-described Invention in most advantageously applicable to the
heating of blast for blast furnaces, puddling furnaces, or refineries, or for the
heating of steam to be used in distilling tallow, palm oil, stearine, stearic acid,
petroleum, boghead coal, shale, or other bituminous substances.
÷ 31.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Alfred Cowper in the Great Seal Patent Office
on the 5th February 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
Alfred Cowper, of No. 354, Great George Street, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of August, in the year of our Lord One
thousand eight hundred and sixty-three, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Edward Alfred Cowper, Her special licence that I, the said Edward
Alfred Cowper, my executors, administrators, and assigns, or such others
as the said Edward Alfred Cowper, 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 Invention for
"IMPROVEMENTS IN FORNACES FOR HEATING AIR, STEAM, AND OTHER ELASTIC
FLUIDS," upon the condition (amongst others) that I, the said Edward
Alfred Cowper, my executors or administrators, 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 Edward Alfred Cowper, 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 Drawings, and
to the figures and letters marked thereon, that is to say :-
My Invention relates to furnaces in which pipes are heated externally
by means of a fire, whilst internally air, steam, or other elastic fluids are
pumped or forced through them, whereby such elastic fluids become heated.
In furnaces hitherto employed for this purpose cast-iron pipes have invariably
been made use of, and, in consequence, no very high degree of temperature bas
been attainable, on account of the melting of or injury to the pipes that has

page_text: occured whenever it has been attempted to raise the temperature of the elastic
fluid much above 700 degrees Fahrenheit.
In the Specification to certain Letters Patent granted to me, and bearing date
the 19th May 1857, (No. 1404,) I mentioned that "pipes of fire-clay cannot
be employed in the ordinary furnaces, as they would leak or crack, and the air
would escape." Now my present Invention consists in making such pipes of
fire-clay or other refractory material capable of being employed for the above
purpose, by the following means:-I line or coat such pipes of fire-clay or other
refractory material with a coating of glaze, litharge, enamel, flux, porcelain,
or other fine clay, or other suitable close-grained substance that will not
permit the passage of the elastic fluid through the sides of the pipes. I prefer
the refractory material for the pipes to be fire-clay, blacklead, or materials
such as are used for crucibles. In some cases I incorporate a portion of the
above-named air-tight materials with the fire-clay, so as to render the pipes as
nearly as possible air-tight. Furthermore, in order to allow of the expansion
and contraction of the pipes of refractory materials without the connections or.
joints leaking or being broken, or the pipes becoming cracked, I cause -the
extremities of such pipes to pass through the brickwork of the furnace, and
there connect them by means of connecting. pipes in the following manner :-
Larrange strong iron bars, girders, or beams, such as "buck staves," outside
the furnace, well tied together by bars or rods above and below or beyond
the furnace, and against these, as points of resistance, I arrange screws or
equivalent means to force the connecting pipes against the pipes of refractory
material, and between such screws and the connecting pipes I place springs or
suitable elastic materials, whereby, whilst exerting the requisite pressure upon
the connecting pipes to insure perfect joints, the pipes of refractory material
are nevertheless at liberty to expand and contract freely. Or in place of the
screws and springs, I employ bell-crank levers with long arms weighted to
any required degree of tension, and short arins pressing against the connecting
pipes, so as to exert the requisite pressure for inaintaining a good joint, and
yet to yield to the expansion and contraction of the pipes; or I attach the
Fonnecting. pipes to the pipes of refractory material by means of screw bolts
fixed to lugs formed on the latter, with or without an elastic me betwee
the pressing surfaces. The connecting pipes may with advanti be mad
curved, and of thin wrought or cast iron, steel, or copper, so to yield to a
slight extent should the pipes of refractory material expand or contract.
unequally,
.
By the foregoing arrangement I am enabled to get at the joints with the

page_text: greatest facility, and to make good any leaky joints that may possibly occur,
without either cooling down the stove or stopping the use of the same except
for a very short space of time.
In combination with the above-described arrangement I sometimes form
some of the heating pipes of cast iron, of the ordinary construction, and cause
the elastic fluid to pass first through these on entering the furnace, and after-
wards through the pipes of refractory material; the iron pipes should in.this
case be placed in the coolest part of the furnace so as not to become. heated
beyond their powers of resistance.
-
The arrangement of the pipes as regards their position in the furnace may
be variously modified; thus they may be horizontal, vertical, or inclined, but
they should be so placed that the heated currents from the fire passing over
their outer surfaces should be broken up, and brought into good contact with
the same; but in most cases the heat from the fire can be best arranged to
enter from one end or the bottom of the furnace, whilst the air, steam, or
other elastic fluid enters the pipes from the other end or the top, and passes.
backwards and forwards through the same, and finally issues at the opposite
end of the furnace to that at which the heat escapes, in a manner well under-
stood and forming no part of my present Invention.
. Furthermore I provide the pipes with plates or pieces of refractory-material
placed inside, to break up or divide the streams of elastic fluid as they pass
through, so that they may the more thoroughly become heated. These furnaces.
can be advantageously heated by the combustion of
gas obtained from such
coke ovens as those patented by Charles William Siemens, on the 18th April
1863 (No. 972), or from such gas producers as those patented by Charles
William Siemens and Frederick Siemens, on the 22nd January 1861 (No.
167), or they may be advantageously heated. by gas from the top of blast
furnaces or from common coke ovens, or by a common fire, or by heat produced
any other convenient manner.
ju
The above-described Invention is most advantageously applicable to the
heating of blast for blast furnaces, puddling furnaces, or refineries, and other
metallurgical operations, or for the heating of steam or gas to be used in
Silimllow, palm oil, stearine, stearic acid, petroleum, boghead coal, or
lis
terminous or non-bituminous substances, or for boiling saponaceous
compounds and other substances, also for heating steam to be passed through
coal, coke, or other carbonaceous materials, for, the production of carbonic
oxi-le, and hydrogen gases, or carburetted hydrogen therefrom, and generally
to such operations in which the air, steam, gas, or other elastic fluids require

page_text: to be heated to a high degree without contact with the fuel or products of
combustion.
Figures 1 to 4, on Sheet I. of the accompanying Drawings, shew one
arrangement of a furnace for heating air, steam, gas, and other elastic fluids, in
which coated heating pipes of fire-clay or other suitable refractory material
are employed according to my Invention.
Figure 1 shews a plan of the same. partly in section; Figure 2 shews a
Jongitudinal section; Figure 3 shews a transverse section; and Figure 4 shews
an end elevation. Similar letters of reference indicate similar parts in each of
the Figures.
The furnace is composed of a fire-brick chamber A communicating at one
end with the spaces B, B, where the requisite heat is produced, and at the
other end by means of the flue C with the chimney. Inside the chamber A
are placed the vertical fire-clay heating pipes D, D, D, coated with any of
the before-mentioned close-grained materials and arranged in such positions as
effectually to break up the currents and absorb the heat from the products of
the combustion of solid or gaseous fuel at B, B, and each zig-zag row of pipes
thus formed is connected at the coolest end of the furnace to the inlet main E,
and at the end nearest the fire-grates to the outlet main F by means of the
connecting pipes G, G¹; the communication between the pipes of each row
being effected at top and bottom by means of the bent iron connecting pipes
H, H, H, and I, I, I, in such a manner that the elastic fluid passes from the
pipe E through the connecting pipe G down the first heating pipe D, and
thence through the bend I, up the second heating pipe D, whence it passes
through the connecting pipe H, down the third heating pipe D, and so on alter-
nately up and down through the whole row until it passes heated to the required
extent into the outlet main F. The outlet main F-is lined with fire-brick in
order to prevent the rapid cooling of the elastic fluid through radiation after it
has left the furnace. The lower connecting pipes I, I, I, are carried by tho
girders J, J, J, resting on the foundation below the furnace, and are protecte:1
from immediate contact with the beat by means of fire-brick slabs K, K, K,
fitting round the ends of the heating pipes D, D, and resting upon flanges
formed upon the connecting pipes I, I, I, the slabs K, K; K, thus forming'
the floor of the furnace. Openings i, i, i, are provided in the side walls of the
furnace below the floor K, K, for the admission of air for keeping the pipes
I, I, I, sufficiently cool. The roof of the chamber A is also formed by means
of slabs of fire-clay K', K', fitting round the upper ends of the heating pipes
D, D, and resting on rims formed: on the same: The upper connecting pipes.

page_text: H, H, are so forced down upon the ends of the heating pipes as to form an
air-tight joint, and yet allow of the heating pipes expanding and contracting.
This is done by the following means:-A series of light iron girders L, L,, L,
are tied to the lower girders J, J, J, by means of the tie rods M, M, and
are provided with series of set screws N, N; these screws are made to
press upon the top of the curved springs 0, 0, 0, the ends of which resting.
upon the flanges of. the connecting pipes H, H, are thus made to press the
same with considerable force against the ends of the heating pipes D. In order
to maintain the connections air-tight, should the heating pipes expand and con-
tract unequally, the connecting pipes are formed as thin as practicable, so as to
to a certain extent elastic, and I prefer to form the ends of the same for this
purpose with an elastic joint P, the arrangement of which and mode of con-
necting the same to the heating pipes will be more fully described hereafter..
It is well known that although with ordinary hot blast stoves constructed
with iron heating pipes, it would be more economical to cause the air to
first enter the pipes at the coolest part of the stove, and issue at the hottest
end near the fire, still such a course is altogether inadmissible, owing to
the fact that the iron heating pipes would in consequence be destroyed very
quickly indeed.
Now it will be seen that by the above-described arrangement [this great
and well-known advantage of causing two currents to pass in close contact
in. opposite directions is here fully obtained, and it is possible to do this on
account of the good fire-resisting properties of the fire-clay pipes, enabling.
those in the hottest part of the furnace to stand the heat without its.
being necessary to cool them by sending the cool elastic fluid first into
them, before it has become partially heated by first entering the pipes at.
the cooler end of the furnace. Thus the heating of the elastic fluid is
effected in the most economical manner, and whilst the products of com-
bustion are thus cooled down,much lower before they pass into the chimney.
the elastic fluid is heated very much hotter than is the case in any stoves
constructed with iron heating pipes exposed to the fire in the usual manner.
If however it is preferred in certain cases to adopt the plan of sending the cool
elastic fluid in at the hottest end, it may be so arranged.
Figures 5 to 8, on Sheet II. of the Drawings, shew an arrangement of
heating furnace generally similar to that just described, with the exception of
the mode of connecting the heating pipes at bottom. Figure 5 shews a plan
partly in section; Figure 6 shews,a longitudinal section; Figure 7 shews a
transverse section ;.and Figure 8 shews an end elevation.
"

page_text: In this arrangement, instead of each zig-zag row of heating pipes D, D,
being connected separately at bottom by means of curved connecting pipes,
cast-iron boxes. I, I, I, are provided, formed as shewn, so as to connect the
lower ends of two of the zig-zag rows of heating pipes together. These boxes
are thereby rendered capable of being made of such a size that a man can
enter them through man-holes Q, Q, Q, for the purpose of making the joints
between the heating pipes and the boxes, and for clearing away through the
holes S', S¹, S, any accumulations of dust, &c., or dirt that may have been
deposited in the chamber A, or on the outside of the pipes. These boxes are
made to fit close together, so as to support the floor of the furnace, composed
of the fire-brick slabs K, K; the brick walls of the furnace stand upon the
boxes as shewn. The boxes are provided with lugs R, R, R, through which
the tie bolts M, M, M, to the girders L.L, L, pass. The other parts of the
furnace are arranged in precisely the same manner as in the before-described
arrangement, and are designated by the same letters of reference, and there-
fore require no further description.
Figures 9, 10, and 11, on Sheet III. of the Drawings, shew another arrange-
ment of furnace. Figure 9 shews a plan of the same; Figure 10 shews
an end elevation partly in section; and Figure 11 shews a longitudinal
section.
In this arrangement the fire-clay heating pipes D, D, D, are placed in a
horizontal position in the chamber A, the fire-grates B, B, being at bottom,
and the flue C to the chimney at top. Gaseous or solid fuel may be used at
B, B. The heating pipes are arranged in zig-zag rows communicating at top
with the inlet main E, and at bottom nearest the source of heat at B, B, with
the outlet main F, and are connected externally at either end by means of
connecting pipes H; H, I, I, in a similar manner to the first-described arrange-
ment, with the exception that in this case the connecting pipes at both ends'
are pressed against the heating pipes by means of the springs O, O, and set
screws N, N, carried by the girders J,.L. These girders are supported in
their required positions by means of distance pieces S, S, S, S, and tie bolts
T, T, T, T, passing through the same, and those on the one side are tied to
those on the other side as in the first arrangement by means of the tie bolts
M, M. As the heating pipes D, D; are placed too closely together to allow
of independent brick walls being built for carrying the ends of the same, I
close in the end surfaces of the chamber A in the manner indicated more clearly
at Figures 54 and 55 on Sheet III. Figure 54 shews a transverse section
hrough the ends of three contiguous heating pipes, and Figure 55 shews a

page_text: section on line X, X, Figure. 54. The. ends of the heating pipes D, D,
are enlarged externally to a slight extent, and formed of a hexagonal
shape, and pieces of fire-clay tile K, K, are inserted between the contiguous
hexagonal sides of the pipes, leaving spaces K', K. externally, that are filled in
with fire-clay luting. The corners of the hexagonal projections on the heating b
pipes are cut off to a slight extent, and the apertures thus formed are. filled
in with fire-clay plugs K, K³, which may be removed when required, .to
observe the interior of the furnace, and for the purpose of introducing imple-
ments through the apertures for freeing the outer surfaces of the heating pipes
from accumulations of dust. As the whole of the heating pipes are by this means ]
-made to rest upon each other, and a certain strain is, thus put upon the side
walls of the furnace, these are firmly tied together by means of the buck staves
U, U, U, U, and tie rods V,.V, V,. V.
:
In place of employing solid fuel for the purpose of heating the furnaces:
gaseous fuel may with advantage be used, particularly in cases in which gases:
can be obtained at a cheap rate, as for example, from the top of a blast furnace.
or from coke ovens, such as patented .by. Charles William Siemens on the
18th April 1868 (No. 972),. or from gas producers such as patented by:
Charles William Siemens and Frederick.: Siemens, on the 22nd January
1861 (No. 167), or from common coke ovens, and a convenient mode of s
arranging the gas burner is shewn in section.and front view at Figures 12 and
13, on Sheet III., where the combustible gas passes from the .pipe a into
the space b, b, whence it issues into the furnace at B, whilst the atmospheric.
air passes through the apertures c, c, in the regulating valve d, and through the
pipes e, e, into the space b, b, whence it issues into the furnace at B and enters
into combustion with the gaseous fuel. The working of the furnace may be
observed. through the apertures c, c. This apparatus is well known and forms.
no part of my Invention.
When, the fire-clay heating pipes are placed in a horizontal position, I
sometimes form them arched, as .shewn in front and end elevation at:
Figures 14 and 15, Sheet III., in order to render them stronger for carrying.
their own weight, and in some cases I form them with a catenary curvature,
as shewn in Figures 16 and 17, either making them the full length shewn, or
of any shorter length, as indicated by the dotted lines..
.
As the heating pipes when made of fire-clay.must necessarily be of a large:
diameter when required to be of any, considerable length, the sectional area of
the pipe is in some cases so large, that if the elastic fluid were allowed to pass
through in a mass undisturbed, the central portion might be imperfectly

page_text: heated, I thereferé prefer to introduce into the pipes loose pieces of fire.
clay or "bafflers," so as to break up the current of the elastic. fluid and
insure the whole of it being brought into intimate contact with the sides of the
pipes, as has long been done-in ordinary superheating apparatus constructed of
metal for superheating steam for steam engines.
Figures 18 to 24 shew longitudinal and transverse sections of fire-clay pipes
with various forms of such "bafflers" a, b, c, d, e, introduced in various posi-
tions for effectually breaking up the current. When the heating pipes are in
vertical positions, as at Figure 25, I introduce into them alternately central
blocks a, a, a, and discs b, b, b, of various forms, as shewn in the transverso
sections at Figures 26, 27, and 28:
Figures-29. and 30, on Sheet IV. of the Drawings, shew a part sectional
plan and sectional elevation of an arrangement in which the fire-clay.heating
pipes D, D, are closed at one extremity and have a partition d formed in them
passing up towards the closed end, thus in effect forming a double pipe. The
openings of the double pipe communicate with separate connecting boxes I, I,
or with separate compartments of the same connecting box, so that the elastie
fluid passes: first up one part of the pipe and then down the other part
of the same, and through the connecting box into another pipe. Three:
rows of pipes. are. here shewn communicating with one set of connecting
boxes.
.
Figures 31 and 32 shew a plan and section of an arrangement in which the
heating pipes D, D, are closed at the lower extremity: Upon the open upper:
ends of the same are fixed metal boxes D¹, D', connecting two of them-
together and bent metal connecting pipes D2, D3, are connected to straight
vertical pipes D³, D³, which pass through these boxes (resting upon the same
with the flanges d, d,) and down to nearly the bottom of the pipes D, D, so that
the current of elastic fluid passes first down the metal pipes D' and D³, then
up through the annular space between the pipes D³ and D, and thence through
the box D' into the second heating pipe D, where it passes down through the
annular space and up through the pipe D³, and so on through the whole.
row.
. By this means the elastic fluid is brought into very intimate contact with:
the sides of the heating pipes, and the convenience of having all the joints at
the top is obtained.
In some cases the external springs need not be employed, but the connecting
pipes and bends may be attached to the ends of the fire-clay pipes by means:
similar to those used for fixing the mouth-picces of ordinary gas- retorts,

page_text: such as the arrangement shewn at Figure 33, where the connecting pipe
His fixed to the heating pipe D by means of T-headed bolts a, a, a.
For this purpose the end of the heating pipe is made somewhat thicker and
recesses are formed in the same into which the T-headed bolts fit.
Figures 34 and 35 shew a plan and elevation of an arrangement for.
pressing the connecting pipes H against the ends of horizontal heating pipes
by means of weighted bell-crank levers O hinged to the girders L, made fast as
before described. The short arm o of the lever is pressed against a stud or
projection on the connecting pipe with a force due to the weighted long arm
o of the lever..
Figure 36 shews an elevation of a similar arrangement with the girder L
placed in a horizontal position and a set screw N interposed between the con-
necting pipe H and the bell-crank lever O.
Figure 37 shews a different arrangement of the weighted lever O with the
girder L placed vertical and a link N in place of a set screw. When the
heating pipes are in a vertical position an ordinary straight weighted lever
may be employed in place of a bell-crank lever.
-
Figure 38 shews an arrangement in which a double coach spring O is
substituted for the curved spring shewn on Sheets I., II., and III. of the
Drawings; and Fig. 39 shews an arrangement in which the spring Q is made
of a spiral form.
:
Figures 40 to 52 shew various forms of connecting pipes arranged so
as to afford the requisite amount of flexibility to allow of the heating pipes
expanding or contracting without causing leakage. In Figure 40 the cast-
iron connecting pipe H is cast with thin wrought-iron or steel discs b, b, inter-.
posed behind the pipe and the end flanges h of the same. The latter are
formed with projecting rims, between which the ends of the fire-clay heating
pipes D, D, fit, and an air-tight joint between the meeting surfaces is made by
means of a cement composed by preference of red lead cement and cast-iron
dust mixed into a stiff putty, annular grooves being made in the two surfaces
to receive the same, as indicated at Figure 53.
....
Figure 41 shews an arrangement in which one thin metal disc b is rivetted.
to the connecting pipe H, and another disc 6 is rivetted to the flange h, and
the outer circumferences of both discs are rivetted together with a metal ring c
intervening.
Figure 42 shews the same arrangement as at Figure 41, with the pipe H
and flange cast to the discs 6, 6. Figure 43 shews an end view applying to
רד
10

page_text: .
Figures 44 and 45 snew a section and end view of an arrangement similar
to the foregoing with the discs b; 6', rivetted together at their circumferences
without any ring being interposed. In this arrangement also, two set screws
N, N, are shewn pressing directly against the connecting pipe H, the requisite
elasticity being afforded by the discs 6, 6', alone.
Figures 46 and 47 shew a section and end view of an arrangement in which
the discs b; b¹, are formed with annular corrugations to allow of a greater
extent of motion.
Figure 48 shews an arrangement in which the connecting pipe H is enlarged
and the discs b, b¹, project inwardly and are connected at their inner edges by
the ring c.
Figures 49 and 50 shew a section and side view of an arrangement in
which the connecting pipe H is formed of thin wrought iron, steel, or copper,
and the flanges h, h, of cast iron. O, O, are the springs that are pressed
against the flanges h, h, by the set screws N, N, carried by the girder L;
d, d; are sight holes closed by plates e, e, and such holes may be used with any
of the other forms of connecting pipes. Any of the arrangements of connecting
pipes may be protected to some extent by pipes or pieces of fire-clay placed
inside.
Figures 51 and 52 shew a section and side view of such an arrangement in
which the connecting pipe H is formed of thin metal. lined with fire-clay, with
enlargements at b, b, to afford the requisite amount of flexibility. The flanges
of the connecting pipes may also be protected by separate rings of fire-clay, as
shewn at e, e. The chimneys of the furnaces are to be provided with dampers
as is usual with hot blast stoves, and the ash-pit may conveniently be pro-
vided with doors when solid fuel is used, and in cases where gaseous
fuel is employed it is convenient to have valves or dampers to shut off
the gas at pleasure, as for instance at "tapping time" with a blast furnace.
: I have found a very useful cement for making the joints of the fire-
clay pipes with the bend pipes or boxes, to be that commonly used for
superheating apparatus for steam engines, consisting of good red lead cement
mixed with a large proportion of cast-iron dust, so as to form a stiff kind of
putty; it is convenient alsó, in order to retain the cement in its place, and
make a good joint, that there should be one, two, or more grooves in the faces.
of the joints exactly matching each. other, so that when well screwed together
there shall be not only cement between the faces, but a body of cement in the.
grooves. Vulcan" cement or other cement capable of standing a high tem-
perature may be used.
-66
:

page_text: Amongst other materials that may be employed besides those herein-before
mentioned as applicable for coating or glazing the fire-clay heating pipes,
oxide of iron, such as is obtained from "mill furnaces," may be employed,
as affording a cheap material for that purpose, or "salt glaze" may be used,
and may even be renewed from time to time by using a little salt when
the heat is well up.
Having now described the nature of my Invention, and the best means
I am acquainted with of performing the same, I wish it to be understood
that I do not limit myself to the various arrangements of furnaces as
herein-before described with. reference to the accompanying Drawings, as
these only serve to indicate some of the various means that may be employed
for carrying the principle of my Invention into practice, nor do I claim gene-
rally the employment of heating pipès of fire-clay or other refractory material,
but what I claim is,-
Firstly, coating pipes of fire-clay or other suitable refractory material
to be employed for heating air, steam, gas, and other elastic fluids, with a
coating of glaze, litharge, enamel, 'flux, porcelain, or other suitable close-
grained substance, separately or in combination, that will prevent the
passage of the elastic fluid to be heated through the sides of the pipes.
Secondly, constructing furnaces for heating air, steam, gas, or other elastic
fluid, in which the heating pipes are formed of fire-clay or other suitable
refractory material coated with a coating of glaze, litharge, enamel, flux, por-
celain, or other suitable close-grained substance, separately or in combination,
that will prevent the passage of the elastic fluid through the sides of the pipes.
Thirdly, incorporating with heating pipes of fire-clay or other suitable
refractory material such close-grained substances of a more or less refractory
nature as will resist the passage of the elastic fluid to be heated through the
sides of the pipes..
Fourthly, forming the joints between the heating pipes of fire-clay:or
other. suitable refractory material and the connecting pipes outside of the
furnace..
Fifthly, making the external.connecting pipes to heating pipes of fire-
clay or other refractory material of thin wrought or cast iron, steel, or
copper, so formed and arranged as to yield somewhat to the unequal expan-
sion and contraction of the heating pipes without causing the joints to become
leaky.
Sixthly, maintaining an air-tight connection. between the heating pipes:
and connecting pipes, by pressing the latter against the former by means of

page_text: springs or weighted levers, so arranged that whilst a constant and sufficient
pressure is maintained, the heating pipes are allowed to expand or contract
without danger of fracture.
Seventhly, combining in furnaces for heating air, steam, gas, and other
elastic fluids, heating pipes of metal with heating pipes of fire-clay or other
suitable refractory material, so arranged that the pipes of metal are situated
in the coolest part of the furnace, and serve to receive the air, steam, gas, or
other elastic fluid before it passes into the fire-clay pipes.
In witness whereof, I, the said Edward Alfred Cowper, have hereunto
set my hand and seal, this Fifth day of February, in the year of
our Lord One thousand eight hundred and sixty-four.
Witness,
C. D. ABEL,
EDWARD ALFRED COWPER. (L.S.)
20, Southampton Buildings, .
Chancery Lane.