IMPROVEMENTS IN STEAM BOILERS
Year: 1880

page_text: LETTERS PATENT to George Hermann Babcock, of Plainfield, in the County of
Union and State of New Jersey, one of the United States of America, and
Stephen Wilcox and Nathaniel Waterman Pratt, both of Brooklyn, in the
County of Kings and State of New York, also one of the United States of
PROVISIONAL SPECIFICATION left by the said George Hermann Babcock
and Stephen Wilcox and Nathaniel Waterman Pratt at the Office of the
Commissioners of Patents on the 29th June 1880.
GEORGE HERMANN BABCOCK, of Plainfield, in the County of Union and State of
New Jersey, one of the United States of America, and STEPHEN WILCOX and
NATHANIEL WATERMAN PRATT, both of Brooklyn, in the County of Kings and
State of New York, also one of the United States of America. " IMPROVEMENTS
IN STEAM BOILERS."
Our improvements are more especially intended for use on ship-board. The
steain space and separating chamber constituting the main body or barrel, is a
horizontal cylinder or barrel with a furnace at one end at a considerably lower
level.
An important portion of the heating surface is formed by a series of inclined
straight tubes arranged parallel to each other and extending over the fire, being
highest at the front end: These parts are secured at the front end in sectional
chambers or front connections, and at the rear end in corresponding sectional or
back connections, which communicate with the rear end of the barrel by a series
of pipes standing slightly inclined.
The furnace is enclosed by tubes, so also is the flue space for the passage of the
gaseous products of combustion under the main barrel. The tubes may be vertical
or slightly inclined. They are connected in sections with provisions for circulating
the water actively through the whole.
We employ a suitable grate and fire bridge. Partial partitions are introduced
to compel the hot gases to move several times across the spaces between the
horizontal pipes.

page_text: The side tubes are connected to the top and bottom chambers, which are by
preference horizontal, and the holes for the insertion of the tubes are by preference
correspondingly inclined, when the tubes are inclined.
We provide a sufficient number of the upright outside tubes to form a wall and
covering to the whole of both sides of the furnace, and also to the combustion
chamber and the flue space through which the hot products of combustion are
carried away.
These are made by preference in several sections on each side, that is, the layers
of tubes which cover one side of the boiler are divided into three or other number
of sets. Each set connects with a corresponding short chamber at the bottom.
The caps of the several chambers are connected by a steam tight joint to the
exterior of the main barrel, each chamber covering and communicating with an
orifice leading to the main barrel.
Being bolted or otherwise fastened, with its openings against a corresponding
opening leading to the main barrel, there is a free passage for the steam and
accompanying water rising from the sides tubes and flowing into the main barrel.
Whenever required for repairs, cleaning, and the like, any section may be removed
and replaced without necessarily disturbing the whole.
We provide a communication between the bottom chambers of the several
sections. This may be effected by means of short thimbles, which are tapped or
otherwise strongly fitted in the adjacent ends of any two chambers, and form a
connection through which the water may circulate.
The sections forming a side therefor operate as one, and the water displaced by
the energetic production of steam in the side pipes at the front immediately against
the furnace may be supplied by a descending current through the side pipes
further rearward, where the heat is less, so that the steam there generated will
offer but slight obstruction to the descent.
A mud drum extends across under the rear of the apparatus, and connects by
pipes to the bottoms of the sectional chambers, and also at each end to the side
chambers.
Provision is made for blowing out or taking out the sedimont at short intervals
by suitable apertures.
A casing, by preference removable in sections, encloses the apparatus.
Orifices may be provided for the insertion of hose for blowing out any ashes,
soot, or any other deposit which may accumulate within the apparatus.
To allow for such cleaning, we provide proper openings through or between tho
several sectional chambers at the front and rear.
The separate sections are mounted a sufficient distance apart, and flanges are
provided which close all the space except the orifices for the insertion of the steam
nozzle.
Doors or openings may also be provided in the sides.
The hot products of combustion are retained within the space under the barrel of
the boiler, and prevented from passing too directly rearward by means of partitions,
thereby forming an "uptake" or ascending flue under the rear end of the barrel.
The gases, on arrival at the bottom of the rear end of the barrel, riso upward
through short flues into horizontal flues.
The horizontal flues are by preference continued out at both ends of the boiler,
and their rear ends covered by doors adapted to be closed when the apparatus is
working.
At the front end of the barrel the gases are collected in a smoke chamber or
"breeching," from whence they flow freely to the stack.
We provide a continuous bed under the whole apparatus, which may serve as a
pan to contain water.
The partition between the base of the smoke chamber and the ash pit may be
formed with a door for the removal of any slight ashes accumulating in the back
part. Ordinary gauges and appliances may be used in conjunction with our
apparatus.

page_text: Hand holes secured by covers may be provided in the top caps and bottom
chambers of the apparatus for the accommodation of the expander in setting
the tubes, or for cleaning or repairs. Our boilers may be arranged singly or in
sets.
The side tubes may be round, oval, or with flattened sides suitably stayed; or
the whole of a side may be made in a single chamber if desired.
Similar letters of reference indicate corresponding parts in all the Figures.
Some of the parts correspond to similar parts in our ordinary well known style.
of steain boiler for land purposes.
Referring to Figs. 1, 2, and 3, an important portion of the heating surface is.
formed by a series of inclined straight tubes arranged parallel to each other, and
extending over the fire, being highest at the front ends. These ordinary parts in our
boiler are indicated by M. They are secured at the front end in sectional chambers
or front connections D, and at the rear end in corresponding sectional chambers
or back connections G, which latter connect with the rear end of the barrel A. by a
series of straight pipes standing slightly inclined, as indicated at H. The grate is
marked B, and the fire-bridge C. Two partial partitions E, F, are introduced in
the ordinary manner to compel the hot gases to move several times across the spaces
between the pipes M.

page_text: These principal members may be like the corresponding parts of our ordinary
land boiler, except for certain modification in the barrel A as follows :—
At each side is formed a series of holes a, which are covered by caps connected
to the upper ends of the sets of side tubes, and allow a strong current of steam and
water to enter the barrel from theso sources.
P, P, etc., are these caps; T are the tubes oxtending up and down at the sides;
and P' are chambers which connect the tubes T together at the bottom. These
tubes are inclined, being further back or towards the rear of the boiler at their
upper ends. The top cap P and bottom chamber P¹ being level it is important that
the holes for the insertion of the tubes T are correspondingly inclined.
We provide a sufficient number of the tubes T to form a tight wall, touching or
nearly touching each other, and covering the whole of both sides of the furnace and
also of the combustion chamber, and the liberal flue space through which the hot
products of combustion move.
But we make these in several sections. We have shown them as three sections on
each side, that is to say, the layer of tubes which extend up and down on one side of
our boiler are divided into three sets; each set connects with a corresponding short cap
at the top and short chamber at the bottom. The caps P of the several chambers
are bolted or riveted with a steam tight joint to the exterior of the barrel A, each
chamber. covering and communicating with one of the orifices a.
Each cap is open
on the face towards the boiler; being bolted with its opening against a corre-
sponding opening a, there is a free passage for the steam and accompanying water
rising from the tubes T and flowing into the barrel A.
Whenever required for repairs, cleaning, or the like, one section P,.T, P¹, can be
taken out and replaced without necessarily disturbing the whole.
We provide a communication between the bottom chambers P₁ of the several
sections. This is effected by means of short thimbles O, which are tapped or
otherwise strongly fitted in the adjacent ends of the chambers and form a liberal
connection through which the water may circulate. The three sections forming a
side therefor operate as one, and the water displaced by the energetic production
of the steam in the pipes T at the front immediately against the furnace may be
supplied by a descending current through the pipes T further rearward, when the
heat is less, so that the little steam there generated will offer but slight obstruction
to the descent.
A chamber I extends across under the front of the grate. It is connected by
pipes J to the bottom of the front chamber D; theso pipes aro of course omitted
opposite to the door. The chamber I connects at each end to one of the bottom
chambers P¹
K is a mud drum extending across under the rear. It connects by pipes L to
the bottoms of the chambers G and also at each end to the side chambers P'.
Provision is made for blowing out or taking out the sediment at short intervals by
hand holes k.
N is a casing of cast or sheet iron, or partly of each, which is removable in
sections of convenient size to allow access to the interior parts when required.
It is important to provide orifices for the insertion of a hose for blowing out
ashes or soot which may accumulate on the pipes M. We attain this by providing
sufficient spaces between the sectional chambers D at the front. This is clearly
shown in Fig. 3, where G are the chambers, made serpentine, as shown, to hold the
tubes M in staggered positions. The serpentine sections are mounted a sufficient
distance apart, and flanges are provided which close all the spaco except the
required small orifices to allow the insertion of the steam nozzle not represented.
We correspondingly construct the back connections G so that a nozzle connected by
a strong hose to the steam space in the barrel above may be successively
introduced in the small orifices at the front to blow out the light matter
accumulated on the tubes M.
The orifices thus provided at the front and rear allow the cleaning of the spaces
between the tubes M at both ends, but there is liable to be an accumulation of such

page_text: light material near the middle of the length, which the strong blast from either end
cannot well reach. We provide high and narrow doors n in the sides of the
casing N, through which a corresponding nozzle or other cleaning agency may bo
introduced laterally to clean the mid-height of the tubes.
We esteem it important to retain the hot products of combustion within the
space under the barrel of the boiler, and not to allow them to pass rearward beyond
the rear ends of the tubes M. To this end we arrango the partial partitions E, F,
as shown, so that there is an up-take or an ascending flue for the gases under the
rear end of the barrel. The gasses on arrival at the bottom surface of the rear of
the barrel find a passage upward into the horizontal flues A', through short vertical
flues A. The flues A are continued out at both ends of the boiler for convenience
of construction and cleaning, but the rear ends are covered by doors, which are
always closed when the boiler is working.
At the front end of tho barrel A the gases are collected in a smoke chamber or
breechen As, from whence they flow freely upward to the stack A*.
We provide a continuous bed of cast or wrought metal under the whole. This
may be made to serve as a pan to contain water, when desired, for additional
safety against fire or other purpose. The partition R between the base of the
smoke chamber and ash pit is formed with a door, which opens forward by
turning on a horizontal axis at the bottom. When this is opened any light ashes
accumulating in the back part can be readily removed through the ash pit.
Our Invention does not prevent the use of the ordinary gauges and other
appliances. We propose to use it with any and all of the ordinary or suitable
styles of boiler attachments.
Hand holes secured by covers 2 are liberally provided both in the top caps P and
and in the botton chambers P' to accommodate the expander in setting the tubes,
and to facilitate repairs.
Our boilers may be used singly or in sets. For a large steam vessel we would
make the parts of moderate size, and obtain the required large production of steam
by using a number of sets.
There is a tendency of the gaseous products of combustion to move obliquely
across the furnace, and clinging close to the top edge of the fire bridge or partition E,
to pass without sufficiently bathing the extreme front end of the boiler. Wo
provide a horizontal extension E' from the front of E near its top, sustained in
position by the tubes M. This, which many inay term a horizontal partition or
horizontal bridge, compels the gases to strike the boiler at the extreme front end,
and to flow along over this horizontal or nearly horizontal bridge, producing their
fullest possible effect till they drop to pass under the partition E.
In the modification shown in Figs. 4 and 5 some general characteristics are
involved, but with points of difference which may be in some situations be very
important. Instead of the side tubes T, the back tubes H, and connections D and G
being gently inclined, as in Fig. 1, all these parts are upright. Instead of the front
connection D and the back tubes H opening into saddling pieces which are under
the body of the boiler, in this modification they open into chambers which aro
formed in one with the adjacent ends of the boiler, and are upon a level with the
lower parts of the boiler ends. Instead of the side tubes T having small ends so
that sufficient strength of metal is afforded in the connections, while the bodies of
the tubes lic in contact or very nearly in contact, in this modification the tubes are
of equal size throughout, and the bodies are necessarily an inch or some other
appreciable distanco apart, and a stratum of fire brick V is provided to resist heat
which is allowed to pass the side tubes by reason of their open arrangement.
In this modification, Figs 4 and 5, there are no flues through the drum. There is
no breechen A³ at the front. The stack forms a direct up-take for the gases as
soon as they have passed through the traverso under the shell. There is a layer of
fire-brick under the bottom of the ash-pit. The mud-drum K instead of being
under the rear ends of the bottom connections P is a considerable distance in rear
thereof, being connected by a short length of pipe. There is no space corresponding

page_text: to the space n in Fig. 1 to allow the introduction of a steam nozzle or other agency
for cleaning. Some or all of these features may be employed in place of the
corresponding features before described.
But what we esteem the most important difference in this modification relates to
the mode of attaching the top connecting chambers P to the barrel A. We have
in this modification made these top chambers complete in themselves, and joined
them by a sufficient number of inclined tubes P, which may be of any required
length, and being expanded or otherwise efficiently joined both to the shell and
the henter; the considerable spaces between these connections P* may be availed
of as openings for the insertion of the clearing hose to blow off the ashes from the
pipes M; W, W, are tiles laid over the lines of connections P* to cover that
important part of the furnace. A little space is left above this, and then a
removable top pieco on each side makes a complete finish. To get at the tubes for
cleaning, it is necessary simply to first lift off the top cover X and then the tiles W ;
then the interior of the furnace may be reached for removing ashes by introducing
a steam or water pipe through the spaces between the pipes P.
This construction among other advantages allows a given width of furnace, and
a given efficiency of boiler to serve with a smaller shell A.
Having thus described our Invention, we would have it understood that we do
not confine ourselves to the exact details as shown and described, so long as the
peculiar character of our Invention be retained, substantially as described.
But what we do claim is,-
First. In a steam boiler having a barrel A with connected heating tubes M, and
their connections D, G, the side tubes T, and connecting chambers P, P', in
combination with each other, and with the connecting-thimbles O adapted to allow
the water to descend in the rearmost tubes T and to ascend in those against the
furnace, as borein specified.
Second. The horizontal-flues A' and connecting-flues A³ in combination with the
barrel A, main heating tubes M, connections D, G, partial partitions E, F, side
tubes T, and enclosing caso N, as herein specified.
Third. In combination with a boiler having a barrel A, main heating-tubes M,
and connections D, C, having orifices for cleaning the exterior of the tubes, the
casing N and side doors n adapted to facilitate the cleaning of the mid-lengths of
tubes, as hercin specified.
Fourth. In combination with the barrel A extending from front to rear of the
boiler, tubes M, front partition E, and one or more partial partitions F in rear
thereof, the horizontal bridge E' arranged as shown to compel the hot gases to
strike the barrel at its front end, as herein specified.
In witness whereof, we, the said George Hermann Babcock, and Stephen
Wilcox, and Nathaniel Waterman Pratt, have hereunto set our hands and
seals, this Fourteenth day of October, in the year of our Lord One thousand
eight hundred and eighty.
Witnesses,
GEORGE HERMANN BABCOCK.
STEPHEN WILCOX.
(L.S.)
(L.S.)
NATHANIEL WATERMAN PRATT. (L.S.)
WILLIAM COLBORNE BROOKES.
CHARLES CAREY STETSON.