IMPROVEMENTS STEAM GENERATORS AND FURNACES
Year: 1868

page_text: LETTERS PATENT to Alexander Clark, of 53, Chancery Lane, in the
County of Middlesex, Engineer, for the Invention of "IMPROVEMENTS
STEAM GENERATORS AND FURNACES,"-A communication from abroad
by S. Lloyd Wiegand, of Philadelphia, in the State of Pennsylvania,
United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Clark.at
the Office of the Commissioners of Patents, with his Petition, on
the 25th April 1868.
I, ALEXANDER CLARE, of 53, Chancery Lane, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN STEAM GENERATORS AND FURNACES," to be as
follows:-
This Invention. consists in forming boilers with double tubes in
several separable sections, and in combining with boilers so formed certain
devices for promoting the activity of the circulation of water therein
[Price 8d.]

page_text: contained, and thus promoting the cleanliness, efficiency, and durability
thereof, and further in the improvement of the furnace, which is so
adapted and applied to said boilers that very great economy of fuel
together with perfect facility of inspection and repairs are cheaply
secured. The boiler is composed of a series of tanks made preferably
of cast iron, although other material will answer
the purpose.
These
tanks are placed side by side in a horizontal position at the top of
the apparatus, and are strongly filletted at all the internal angles,
while the apertures at the ends are closed by means of elliptic plates
with a bridge and bolt in the manner of manholes of boilers. Upon
the bottom side of the tanks are formed conical trumpet-shaped
adjutages (which strengthen the bottom of the tank and facilitate
the flow of fluids from the tubes into the tanks) with their larger
ends or
mouths inside of the tanks, and into which adjutages are
screwed metallic tubes (lap-welded wrought iron or steel tubes answering
the purpose very well) of suitable diameter and length, which tubes
are closed at their lower extremities by metal caps screwed thereon.
Inside of each of the tubes already described and resting upon a
support in the caps is placed a smaller tube extending up into a
portion of the tanks, upon the outer side of which tubes I place spiral fins
or feathers which operate to produce rotative motion of the ascending
water columns contained in the annular spaces between the internal
and external tubes. These spiral fins or feathers may be either of
a uniform or accelerated pitch, or may be either continuous spirals
or interrupted segments, and if used in the adjutages present an
appearance of a Jonval turbine water wheel. The rotative motion
produced in the water column contained in the annular spaces
between the external and internal tubes is continued by reason of the
momentum of the water after it reaches the interior of the tanks, and
the current is spread and diffused in such a manner as to prevent
the bubbles of steam that may be carried up with the water from
the tubes rising in such close contiguity to the inside smaller tubes as
to
interfere with an ample supply of water entering the upper ends
of the smaller tubes. The upper ends of the internal tubes above
mentioned which extend into the tanks are made with mouths upon
the sides so formed, and directed towards the external current as to
collect a supply of water from the revolving current. The upper end
may be made either of a tapering form or expanded. Above the tops
of the internal tubes I place a perforated plate or plates which break

page_text: up and distribute the bubbles of steam, which rise from the tubes
in such a manner that the steam is liberated from the water nearly
uniformily over the whole surface of the water, and in this manner
dry steam is furnished without necessitating the use of superheaters,
The several sections or
or dry pipes or any height of steam drum.
tanks are connected together by means of a steam drum and are
supplied with water from branches of tube extending from the main
feed pipe to the several tanks. The level of water in each of the tanks
or sections, since they are all connected both above and below the
water line, will be uniform in all the tanks, and may be ascertained by
guage cocks placed in a stand pipe or by any of the known appliances
for the purpose. A safety valve of the usual form is also applied to this
boiler. The furnace used to supply the heat to this improved steam boiler
is arranged with a chamber above the grate in which combustion of
the gaseous products of the fuel is completely effected, and the flame
Underneath
and gases pass between the several tubes to the chimney.
the lower ends of the tubes is a chamber which affords access to
the tubes and caps of the steam boiler, for the
and repair of those parts, and which may be
at the back of the ash-pit or in the side wall.
fuel it is advantageous to place a perforated arch and a perforated
partition wall in the furnace chamber, thus forming a second chamber
and causing all the gaseous products of the fuel to pass into it and
the second chamber, and there mingling with air to burn before passing
This
into the chamber containing the tubes of the steam generator.
more convenient inspection
entered from a door either
With some varieties of
is found in practice to be a very advantageous arrangement, and in
cases where steam is generated from the waste gases of smelting
furnaces and cupolas the intermediate combustion chamber in which
gas is mixed with air and burned before coming in contact with the
heating surface of the boiler is found to be almost imperatively essential
to demonstrate a good economy. In other respects from those already
I
described the furnace does not differ from those in general use.
sometimes instead of screwing the caps upon the lower ends of the
water tubes directly upon the tube have a cup or box screwed upon
the lower end of the tube, the bottom of which is removable like
the elliptic plates which are employed by engineers to close the man-
holes of steam boilers, and when in position are kept there by the pressure
of the contents thereof, thus affording a ready means of inspecting and cleaning
L

page_text: this steam generator
and
realized in causing
being heavier than
Having described the construction of
furnace I will now describe the mode of using the same. Having
filled the tubes with water above the level of the, perforated diaphragm I
ignite the fuel in the furnace, and by the heat so produced expanding
the water contained in the annular.. spaces between the small tubes
and the large tubes, an ascending current is produced, which is fed
in the caps below by the specifically heavier column of water contained
in the tubes flowing down from the tanks. This action gradually
accelerates until steam is formed, when it becomes very rapid. The
water in the tubes in rising does not rise perpendicularly, but meeting
the spiral guides, rotates spirally and disperses tangentially from
the adjutages in the tanks.
the water to rotate in the
the steam bubbles, therein
centrifugal force, is forced into more intimate contact with the internal
surfaces of the tubes; and second, the rising of the steam and water
from the external tubes into the tanks. does not interfere with a
descent of a supply of water in the internal tubes; and third, a
thorough agitation of the water overlying the bottoms of the tanks
prevents the precipitation of mud or sediment upon the bottoms of
the tanks. The bubbles of steam rising from the tubes are inter-
cepted and broken by the perforated diaphragms, so that they leave
or separate from the water nearly uniformly over the entire surface,
thus enabling me to use tanks or vessels of very inconsiderable
height as compared with any other boiler heretofore used, and I thus obtain
an ample supply of dry steam without incurring the risks inseperable from the
use of large containing vessels.
A threefold advantage is
tubes. First, the water
contained, and therefore having a greater
[ ..
"
The following advantages are realized in the use of a boiler so
constructed: It is safe from any possibility of disastrous explosion,
because none of the vessels containing the steam are large enough
to do any mischief if bursted when under pressure, and the caps at
the lower ends of the tubes being the weakest part of the boiler, and
at same time the cheapest, are always the parts that break and are
cheaply and quickly replaced. It does not require skilled labor in
its erection; it is capable of indefinite extension; being in sections it g
can be transported in parts more readily than other boilers; it can
be made at a less cost than other boilers; it can be repaired more readily
than other boilers and at less cost; it is self-cleaning it

page_text: economical in fuel; it is lighter than other boilers of equal steam generating
capacity; it is more compact than other boilers of the same power; it costs
less to erect than other boilers; it can be inspected in all parts readily
when in use.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Clark in the Great Seal Patent Office on the 5th
September 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer, send
greeting.
!
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of April, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-first
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Alexander Clark, Her special licence that I,
the said Alexander Clark, my executors, administrators, and assigns,
or such others as I, the said Alexander Clark, my executors, adminis-
trators, 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 STEAM
GENERATORS AND FURNACES," a communication to me from abroad by S.
Lloyd Wiegand, of Philadelphia, in the State of Pennsylvania, United
States of America, upon the condition (amongst others) that I, the' said
Alexander Clark, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals,
should particularly described and ascertain the nature of the said
Invention, and in what manner the same
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 'Letter's
Patent.

page_text: be performed, to be particularly described and ascertained in and by-the
following statement, reference being had to the Sheet of Drawings here-
unto annexed, and to the letters and figures marked thereon (that is
to say):-
in
This Invention consists in forming boilers with double tubes
several separable sections, and in combining with boilers so formed certain
devices for promoting the activity of the circulation of water therein
contained, and thus promoting the cleanliness, efficiency, and durability
thereof, and further in the improvement of the furnace, which is so
adapted and applied to' said boilers that very great economy "of fuel,
together with perfect facility of inspection and repairs are cheaply
secured.
.
This Invention is illustrated in the annexed Drawings forming part of this.
Specification. The same letters of reference apply.to the same parts of the
several Figures.
Figure 1 shows a top plan of the apparatus; Figure 2, a front
elevation; Figure 3, a side elevation, and Figure 4, a sectional side
elevation of same; Figure 5 shows an enlarged section of a portion
of one of the tanks and the tubes connected therewith; Figure 6 shows a
view of the hand hole plate for closing the ends of the tanks; Figures 7,
8, and 9 show modifications of the internal tubes, while Figures 10
and 11 show a modification of the cap for closing the ends of the
tubes.
preferably of cast
These tanks are in
C, C, C, C, represent a series of tanks made
iron, although other material will answer the purpose.
the boiler shown in the Drawing in external dimensions four feet
eight inches in length, eight inches in width, and ten inches in height,
exclusive of the adjutages and projections for connecting the steam
The thickness of metal in these
and water pipes herein-after described.
tanks C is three-fourths of an inch, and they are strongly filletted in all
the internal angles, while the apertures at, the ends are closed by means
of elliptical plates D with a bridge E and bolt F in the manner of man-
holes of boilers. Upon the bottom side of the tanks C are formed
conical trumpet-shaped adjutages G (which strengthen the bottom of
the tank and facilitate the flow of fluids from the tubes into the tanks)
with their larger ends or mouths inside of the tanks, and into which
adjutages are screwed metallic tubes H (lap-welded wrought iron or
steel tubes answer the purpose very well), for example, of two inches

page_text: and a fourth external diameter, two inches internal diameter, and five
feet in length, which tubes H are closed at their lower extremities by
metallic caps I screwed thereon. Inside of each of the tubes already
described, and resting upon a support K in the caps I is a small tube L
extending up into a portion of the tanks C, upon the outer side of which
tubes I place spiral fins or feathers M which operate to produce a
rotative motion of the ascending water columns contained in the annular
spaces between the internal and external tubes; these spiral fins or
feathers M may be either of a uniform or accelerated pitch, or may
be either continuous spirals or interrupted segments, and if used in
the adjutages G present an appearance of a Jonval turbine waterwheel, as
shown in Figure 9. The rotative motion produced in the water column
contained in the annular spaces between the external and internal tubes
is continued by reason of the momentum of the water after it reaches
the interior of the tanks, and the current is spread and diffused in such
a manner as to prevent the bubbles of steam that. may be carried up
with the water from the tubes rising in such close contiguity to the
inside smaller tubes as to interfere with an ample supply of water entering
the upper ends of the smaller tubes. The upper ends of the internal
tubes L which extend into the tanks are made with mouths N upon
the sides, so formed and directed towards the external current as to
The upper end
collect a supply of water from the revolving current.
may be made either of a tapering form, as shown in Figure 7, or
expanded, as in Figures 8 and 9. Above the tops of the internal
tubes L I place a perforated plate or plates O which break up and
distribute the bubbles of steam which rise from the tubes in such a
manner that the steam is liberated from the water nearly uniformly
over the whole surface of the water, and in this manner dry steam is
furnished without necessitating the use of superheaters or dry pipes or
any height of steam drum.
The several sections or tanks C are connected
together by means of a steam drum P, and are supplied with water
from branches of a tube Q, Q, Q, extending from the main feed pipe R
to the several tanks C. The level of the water in each of the tanks or
sections, since they are all connected both above and below the water
line will be uniform in all the tanks C and may be ascertained by guage
cocks S placed in a stand pipe T, or by any of the known appliances
for the purpose.
A safety valve of the usual form is also applied
to this boiler upon the drum P. The furnace used to supply the heat to
this improved steam boiler is arranged with a chamber A above the grate,

page_text: in which the combustion of the gaseous products of the fuel is com-
pletely effected, and the flame and gases pass between the several tubes
to the chimney. Underneath the lower ends of the tubes is a chamber U
which affords access to the tubes and caps of the steam boiler for the
more convenient inspection and repair of those parts, and which may
be entered from a door V in either the back of the ash-pit or in the side
wall. With some
varieties of fuel it is advantageous to place a
perforated arch W and a perforated partition wall X in the furnace chamber,
as shown by the dotted lines in Figure 4, thus forming a second
chamber Y, and causing all the gaseous products of the fuel to pass
into it and the second chamber, and there mingling with air to burn
before passing into the chamber containing the tubes of the steam
generator. This is found in practice to be a very advantageous arrange-
ment, and in cases where steam is generated from the waste gases
of smelting furnaces and cupolas the intermediate combustion chamber Y,
in which gas is mixed with air and burned before coming in contact
with the heating surface of the boiler is found to be almost imperatively
essential to demonstrate a good economy. In other respects from those
already described the furnace does not differ from those in general use. I
make the caps I upon the lower ends of the tubes H sometimes as shown in
Figures 10 and 11, where instead of being screwed directly upon the tube I
have a cup or box screwed upon the lower end of the tube, the bottom of which
box is removable, like the elliptic plates which are employed by engineers to
close the manholes of steam boilers, and when in position are kept there by
the pressure of the contents thereof, thus affording a ready means of inspecting
and clearing the tubes.
Having described the construction of this steam generator and furnace I will
now describe the mode of using the same.
Having filled the tubes with water above the level of the perforated
diaphragm I ignite the fuel in the furnace, and by the heat so produced
expanding the water contained in the annular spaces between the small
tubes and the large tubes an ascending current is produced, which
is fed in the caps below by the specifically heavier column of water con-
tained in the tubes flowing down from the tanks. This action gradually
accelerates until steam is formed, when it becomes very rapid. The
water in the tubes in rising does not rise perpendicularly, but meeting
the spiral guides rotates spirally and disperses tangentially from the
adjutages in the tanks. A three-fold advantage is realized in causing

page_text: the water to rotate in the tubes. First, the water being heavier than
the steam bubbles therein contained, and therefore having the greater
centrifugal force, is forced into more intimate contact with the internal
surfaces of the tubes; and, second, the rising of the steam and
water from the external tubes into the tanks does not interfere with a descent
of a supply of water in the internal tubes; and, third, a thorough
agitation of the water overlaying the bottoms of the tanks prevents
the precipitation of mud or sediment upon the bottoms of the tanks.
The bubbles of steam rising from the tubes are intercepted and broken
by the perforated diaphragms, so that they leave or separate from
the water nearly uniformly over the entire surface, thus enabling me to
use tanks or vessels of very inconsiderable height as compared with any
other boiler heretofore used, and I thus obtain an ample supply of dry
steam without incurring the risks inseparable. from the use of large
containing vessels.
The following advantages are realized in the use of a boiler so con-
structed: It is safe from any possibility of disastrous explosion, because
none of the vessels containing the steam are large enough to do any
mischief if bursted when under pressure, and the caps at the lower ends of
the tubes being the weakest part of the boiler, and at the same time the
cheapest are always the parts that break, and are cheaply and quickly replaced;
it does not require skilled labor in its erection; it is capable of indefinite
extension; being in sections it can be transported in parts more readily than
other boilers; it can be made at less cost than other boilers; it can be repaired
more readily than other boilers and at less cost; it is self-cleaning; it is most
economical in fuel; it is lighter than other boilers of equal steam generating
capacity; it is more compact than other boilers; it can be inspected in all parts
readily when in use.
Having described the nature of this Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is,―
1st. The making of boilers with double tubes in separate sections susceptible
of indefinite extension, as described.
2ndly. The conical adjutages uniting the tubes with the tanks, as described
and shown.
3rdly. The caps upon the lower ends of the tubes as shown and
desesibed

page_text: 4thly. The spiral guides or wings, substantially described and shown.
5thly. The lateral mouths formed on the internal tubes, as shown.
6thly. The perforated diaphragm described and shown.
7thly. The chamber below the tubes, as described, affording access to the
tubes.
8thly. The combination of the furnace made as described, with the steam
generator formed and placed as drawn and described.
this
Fourth day of
Fourth day of September, in
In witness whereof, I, the said Alexander Clark, have liereunto
set my hand and seal,
the year of our Lord One
eight.
thousand eight hundred and sixty-
Witness,
A. M. CLARK,
Patent Agent,
53, Chancery Lane,
London.
ALEXR. CLARK. (L..S.)