IMPROVEMENTS IN STEAM BOILERS AND GENERATORS
Year: 1869

page_text: LETTERS PATENT to Silas Covell Salisbury, of the City of New York,
and State of New York, in the United States of America, Civil
Engineer, for the Invention of "IMPROVEMENTS IN STEAM BOILERS AND
GENERATORS."
Sealed the 11th January 1870, and dated the 28th October 1869.
PROVISIONAL SPECIFICATION left by the said Silas Covell Salisbury
at the Office of the Commissioners of Patents, with his Petition,
on the 28th October 1869.
I, SILAS COVELL SALISBURY, of the City of New York, and State of
New York, in the United States of America, Civil Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN STEAM
BOILERS AND GENERATORS," to be as follows:-
The furnace of the boiler or generator consists of an inner or fire
chamber B, called the preparing chamber, in which the fuel is burned,
and an outer chamber B', called the combustion chamber, in which the
gases and products of combustion evolved from the burning of the fuel
are burned and utilized. The water chamber consists of two separate

page_text: chambers, the inner one C of which is generally of smaller capacity than
the outer one A, and is placed between the preparing and combustion
chambers, so that both sides thereof are subjected to the greatest heat,
thereby evaporating the water rapidly; such inner chamber is connected
with the outer one by pipes b, b, at its base, and c at its crown, so as to
produce rapid circulation. The inner or preparing chamber of the
furnace may be placed some little distance within the main water
chamber of the boiler, as shewn in Figure 1, and the outer or combustion
chamber B¹ extends over and down upon the sides of the preparing
chamber, as also shewn in such Figure. To each such chamber large
quantities of air are supplied from below through openings 9, 9, which
may be so arranged that the same openings will supply both chambers
at the same time. Superheated steam may also be supplied to such
chambers at the same time by a perforated tube connected with the
boiler, or any steam supplied which may be so placed as to discharge the
superheated steam under and into the openings furnishing the air. The
pressure and velocity of the steam thus supplied will cause increased
draft, and consequently an increased quantity of oxygen will be supplied.
The walls or sides of the inner or preparing chamber of the furnace are
pierced with horizontal openings or fitted with horizontal tubes f, f,
through which the air and decomposed steam are continually supplied to
such chamber on every side thereof in small or divided jets at or near
the top of the burning fuel, as also at different points below, so that
such air and steam are presented to and distributed through every part
of the burning fuel. The decarbonization of the fuel thus commences or
is carried on most actively from the top and side of the furnace instead
of principally from the bottom, thereby producing an intensified heat
with a comparatively slow combustion of fuel. The grate bars thus
remain comparatively cool, and are consequently durable. Com-
munication between the inner or preparing chambers and the outer or
combustion chamber is effected by openings or tubes d, d, passing
through the arch or crown of the preparing chamber, which is the inner
water chamber of the boiler. The carbonic oxides and products of
combustion formed in the fire chamber in passing through such tubes
into the combustion chamber are divided into numerous small currents,
and thereby come in complete and intimate contact with and are
effectually mixed with the jets of air and steam supplied to the com-
bustion chamber, and an immediate chemical union and utilization of
such gases of the coal and air or air and steam takes place, and their

page_text: complete combustion is produced. Air is also admitted through the
grate bars, the openings in which should be numerous and large. The
inner water chamber C which separates the preparing and combustion
chambers of the furnace is best made of boiler plates firmly rivetted
together and braced, and of the shape adapted for a fire-box, placed
generally about two inches apart, so as to bring a comparatively small
quantity of water in immediate contact with the hottest parts of the
furnace, and thus accelerate evaporation. Communication between the
main water chamber A and the inner chamber C is effected by tubes b, b,
entering the bottom of such inner chamber, and other tubes c, c, which
extend from the top of such inner chamber and open into the main or
outer water chamber. By such connection and the action of the fire
upon the comparatively small body of water in the inner chamber a
constant and active circulation of the whole body of water in the boiler
is secured towards that part of the boiler where the heat is the greatest.
The fire surface of such inner water chamber is increased by the extent
of surface of the tubes d, d.
The construction of inner water chamber, as described, with numerous
fire tubes or pipes d, d, is best adapted when using hard or anthracite
coal. When soft or bituminous fuel is used a construction of inner
water chamber, such as is shewn in Figures 4 and 5, is preferable.
Here the plates forming the inner chamber instead of being pierced with
tubes are entire or continuous, but a portion of such water chamber is
cut away, as shewn at 1, Figure 4, so that the gases and products of
combustion can pass from the inner or preparing chamber of the furnace
into the combustion chamber in a body or mass. When the front part
of the water chamber C is thus cut away the doors or front plates of the
boiler are perforated, as shewn in Figure 4, for the admission of air into
the combustion chamber to be mixed with such gases and products of
combustion and secure their combustion. In return flue boilers when
the products of combustion pass up at the rear of the water chamber air
will be supplied through perforations behind or in the bridge wall of the
furnace.
A modification of this arrangement of separate fire and water
chambers as applicable to upright tubular boilers with water legs at the
sides of the fire chambers is shown in Figure 3. In this case the inner
water chamber C, which separates as in the constructions before
described the preparing and combustion chambers, is formed by con-

page_text: necting the opposite water legs by a thin shell C', which opens into each
opposite leg; such shell is pierced and fitted with numerous tubes d¹, d¹³,
as in the first-described arrangement, through which the gases and
products of combustion pass from the preparing to the combustion
chamber, to the latter of which air is admitted. From the top of such
inner water chamber rise one or more water pipes c', c', which pass into
the main water chamber of the boiler and extend up to or above the
ordinary water line, and open into such chamber through numerous
orifices h in the sides of such pipes, as shewn in the Figure, the ends of
such pipes being closed. Circulation between the inner and outer water
chambers is effected as before described, but the water from such tubes
is discharged horizontally in numerous jets or streams amongst the
hot-air tubes of the boiler.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Silas Covell Salisbury in the Great Seal Patent
Office on the 28th April 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SILAS
COVELL SALISBURY, of the City of New York, and State of New York,
in the United States of America, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of October, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Silas Covell Salisbury, Her
special licence that I, the said Silas Covell Salisbury, my executors,
administrators, and assigns, or such others as I, the said Silas Covell
Salisbury, 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 STEAM BOILERS AND GENERATORS," upon the condition
(amongst others) that I, the said Silas Covell Salisbury, 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

page_text: 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 Silas Covell Salisbury, 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 :-
The objects of this Invention are to economise the use of fuel in
generating steam, and to render the same more effective by utilising
its gases and securing their more perfect or complete combustion, and
by the peculiar construction and arrangement of the water chambers
of the boiler to as well increase the fire surface as cause the most intense
heat to be applied to a small portion of the water, and also produce
and secure a continual and rapid circulation of the whole body of the
water toward that part of the boiler acted upon by the greatest heat,
accomplishing these results by the combustion of a comparatively small
quantity of fuel.
This Invention and its mode or manner of operation will be shewn by
reference to the accompanying Drawings, and the letters of reference
marked thercon.
Fig. 1 is a view, partly perspective and partly sectional, showing one
form of construction of my Invention.
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2 is a partial view of the bottom of Figure 1 taken through it
just above the grate bars.
3 is a view showing the application of my Invention to the
ordinary upright tubular boiler.
4 is a sectional view, lengthwise, of a different construction
embodying my
Invention.
5 is a sectional view, crosswise, of the same construction shown
in Figure 4.
The external construction or form of the main or outer water
chamber A of the boiler may be substantially the same as in boilers
generally heretofore constructed, and having when desired water legs a, a,
extending down on the sides of the fire chamber. The furnace B, B',
is placed inside the boiler, or between its water legs, or their equivalent,
as in ordinary cases, and the grate or grate bars are substantially like

page_text: those generally used, except that the openings or air passages therein
should most preferably be as large as possible, and be divided into
many distinct passages, so as to not only supply large quantities of air
to the bottom of the fire, but also to divide the air as it is admitted to
the fire into numerous currents. The fire chamber B, and which is
called the preparing chamber of the furnace, instead of being directly
in contact with or its walls forming the inner walls of the main water
chamber A may be placed within the outer or combustion chamber B',
and separated some little distance from the main or outer portion of the
boiler, as shown in Fig. 1. Such chamber is formed except as to its
grate surface by a shell or hollow chamber C, which is the inner water
chamber, which is made of boiler iron firmly riveted together and braced
and of the shape required or desired for a fire-box, the plates forming
such shell being generally about two inches apart. The space or chamber
between such plates is a water space or chamber, within which the water
of the boiler is heated and through which it circulates, such shell or
inner water chamber C connecting with the main or outer water chamber
at either side and near the bottom by two or more tubes or pipes b, b,
which open into the main or outer water chamber or its water legs a, a,
and by similar tubes or pipes c, c, extending from the top of such shell
and which open into the main water chamber A above the furnace.
The shell or inner water chamber C will thus be kept continually full
of water from the main or outer chamber, and as the water in such shell
becomes heated it rises and passes out through the tubes c, c, into the
outer water chamber, while at the same time the water from such
chamber rushes into the inner chamber or fire shell C through the
pipes b, b. A constant and active circulation of the whole body of the
water in the boiler is thus secured, and such circulation is constantly
towards and in contact with that part of the boiler where the heat is
the greatest and the evaporation is most rapid. The tubes c, c, extend-
ing from or near the top of the shell C into the water chamber above
it should be numerous and large enough to allow the water to be freely
and rapidly discharged through them, but they should not be so numerous
but that the water will pass from the inner to the outer water chamber
with a considerable force or pressure so as to ensure a more rapid circulation
of the whole body. The walls of such shell or water chamber C are also
perforated with numerous holes scattered over their entire surfaces to
within about a foot of the bottom, as shown in Fig. 1, and which are fitted
with tubes d, d, Fig. 1, of about an inch or thereabouts in diameter properly

page_text: These tubes are fire
tubes and form the means of connection between the fire or preparing
chamber B and the outer or combustion chamber B'. The direct action.
of the burning fuel is thus rendered effective not only upon the wall of
the fire chamber or the inner plate of the water chamber C, but also upon
the surfaces of the tubes d, d, by the passing of the heated products of
combustion through them, and the fire surface of the boiler directly
acted on by the burning fuel is thus increased by the extent of the
surface of all such tubes. For about a foot from the bottom of the fire
chamber or furnace B the sides or walls of such chamber are pierced
and fitted with about three-cighths inch tubing f, f, f, and which are
placed about two inches apart or distant from each other. These are air
tubes for the admission of air into the fire or preparing chamber B,
such air being supplied or admitted through suitable and sufficient
openings g, g, in the bottom. Surrounding such lower part of the
chamber C, and covering the mouths of the tubes f. f. f. I place wire
gauze or loosely woven asbestos cloth to divide or fractionise the air as
it passes through such tubes into and upon the burning fuel, and also to
heat it as it passes to the fuel. By means of such tubes air is continually
furnished to the fire or preparing chamber, and enters such chamber in
small or divided jets on every side of the burning fuel, and at or near
the top thereof and at different points below, and is thus presented to
and distributed through every part of the burning fuel. To such fire or
preparing chamber B there is also admitted through or by means of a
pipe extending underneath the openings 9, 9, and opening into them by
means of small perforations or jets steam or superheated, steam (taken
from the boiler or any convenient or suitable source), which becomes,
decomposed in passing into or on entering such chamber, furnishing
additional oxygen, and also hydrogen, and thereby assisting to perfect a
more complete and perfect combustion of the fuel. By thus supplying
the fire or preparing chamber on every side thereof and on the top of
and at different points of the burning fuel with divided jets of air and
decomposed or decomposing steam, the decarbonisation of the fuel
commences or is carried on from the top and from the outside of the
furnace instead of principally from the bottom, but at the same time
the intense heat penetrates the centre and completely effects. the same
results there. A very intensified heat is thus produced, and with a
comparatively slow combustion of fuel, and as such combustion is
carried on most actively from the top and sides of the fire the under
swedged or tightly fixed in such openings.

page_text: surface of the grate bars, notwithstanding the great intensity of the
heat, remain quite cool comparatively, and consequently will last much
longer than they could under ordinary circumstances with a fire of a
much less intensity. The combustion chamber B¹ is outside of and
surrounds the fire or preparing chamber B, communication between
those two being solely through or by means of the small tubes or
pipes d, d, which pass through the inner water chamber C. The carbonic
oxydes and products of combustion formed in the fire or preparing
chamber by passing through the tubes d, d, are divided into numerous
small currents, and enter such combustion chamber at many different
angles, and are thus caused to come in more complete and intimate
contact with and thereby be more effectually mixed with the jets of
air and steain which enter such chamber as well as the fire or preparing
chamber. Air and steam are supplied to the combustion chamber B
through the same openings g, g, and by means of the same steam pipe
which supply the air and steam to the fire chamber. A perforated plate
or diaphragm i placed just above the series of air tubes f, f, f, allows
the air and steam entering below to pass upward, part of it into the
combustion chamber, at the same time dividing the air and steam so
entering the combustion chamber into numerous currents, so as to
ensure their more general distribution among and mixture with the
products of combustion and gases entering such chamber from the
fire or preparing chamber. Such diaphragm also serves to arrest or
obstruct the passage upward of the air and steam, and deflects the
larger portion backward and downward, and causes them to enter the
fire or preparing chamber through the tubes f, f, f, for the purposes
specified. The air becomes heated while passing to the combustion
chamber, and is rendered lighter than the carbonic oxydes continually
being poured into such chamber from the fire chamber, and an immediate
chemical union and utilisation of such gases of coal, air, and steam takes
place, and their complete and perfect combustion is produced. The
pressure and velocity of the steam escaping upward from the pipe sup-
plying it also produces or causes an increased draft, and consequently
an increased amount of oxygen is carried in and supplied to both the fire
and combustion chambers. Actual experiment has proved that such use
of steam in such chambers adds greatly to the economy produced by the
general combination. The quantity of air and steam supplied to the fire
and combustion chambers may be governed and regulated by a sliding
plate so arranged as to graduate or vary the size of the openings g, g.

page_text: The heat and products of combustion after leaving the combustion
chamber pass off through the tubes k, k, into the smoke stack or chimney.
By thus making a part of the boiler form the fire chamber or chamber
in which the fuel is burned, and placing such part of the boiler between
the two chambers of the furnace, communication between which is by
means of fire tubes passing through that part of the boiler making the
fire chamber, an inteuse heat is made effective upon both sides of a com-
paratively small body of water, and also in many directions through
such body of water, thereby causing large and rapid evaporation, and by
means of the peculiar mode or connection between the inner and outer
water chambers of the boiler a continuous and rapid circulation of the
whole body of water in both chambers is going on and every portion of
the water brought in contact with the most intensely heated surfaces, a
largely increased evaporation or production of steam is thus obtained,
and by the consumption of a comparatively small quantity of fuel. Such
fire chamber shell or inner water chamber may also be composed of a
series of horizontal water tubes, generally about two inches in diameter,
and placed about an inch from each other, which connect at either end
with and open into hollow arched chambers, such chambers connecting
with the main or outer water chambers by means of tubes at the bottom
and at the top as before described, and by which circulation is effected
substantially the same though perhaps not quite so rapid as when the
inner water chamber is constructed as shown in Figure 1. A covering
of heavy wire cloth upon the outside of the horizontal water tubes serves
to more effectually divide into separate currents the carbonic oxydes
and products of combustion as they pass from the fire to the combustion
chamber, and thus prepare them to be more easily and completely mixed
and combined with the air and steam entering that chamber. By the
use of a furnace and boiler thus constructed the escape of sparks is
prevented, the small particles of fuel escaping from the fire chamber
are consumed in the combustion chamber and consequently the flues
are but little if any injured by them, the fire-box or chamber is far less
likely or liable to bo burned out than when ordinary furnaces are used
and thus a great saving in repairs is effected, there is far less liability to
injury and breakages from or by reason of the great strain produced by
extreme contraction and expansion when one plate is kept so very hot
and the other is comparatively cool, as in ordinary boilers and as the
water is rapidly conveyed to the hottest part of the boiler from the
colder parts it absorbs or takes up the extreme heat, thus heating the

page_text: water as fast as it comes in contact with such hotter part, and as this is
discharged above the water in the main boiler it at once becomes steam.
The steam generating capacity of a boiler when so constructed is increased
very largely nearly or quite one third. Such construction of steam
generator has been found to operate highly satisfactorily and with
greatly effective results when anthracite or other hard coal is used as fuel,
but does not operate so satisfactorily or effectively when soft coal or
wood is used as fucl, as the pipes passing from the inner to the outer
furnace chamber are then liable to be more or less filled with the heavy
products of combustion evolved in the inner furnace chamber.
Figures 4 and 5 show a steam generator constructed upon the same
general principles, but more especially adapted to the burning of the
soft or bituminous and semi-bituminous coals, wood, and other fuels
producing when burned thick dense vapors or smoke. Instead of having
the plates of the inner water chambers C pierced and connected by tubes
as before described, I make such inner water chamber with continuous
or solid plates and cut away such plates at one end and at the top as
shown in Figures 4 & 5, so as to make the connection between the
inner and outer chambers of the furnace by means of a single large
opening instead of by means of many small ones distributed over the
entire surface of the preparing chamber B of the furnace. Through such
opening the products of combustion and gases generated in the preparing
chamber pass into the outer or combustion chamber where they are con-
sumed. Circulation between the inner and outer water chambers is
effected as before described, by means of tubes b, b, entering the bottom
of the inner chamber and discharging tubes c, c, rising from the top
thereof. In the case of a direct flue boiler such as is used in locomotives
such opening will best be placed or made through the front end of the
inner water chamber as shown in Fig. 5, as by such position the heat
will be rendered most effective upon such chamber, the heated gases, &c.
being first brought in contact with the inner wall of such chamber and
then upon or over the outer wall before they enter the flucs of the
boiler. In the case of a return flue boiler such opening may be made
at the rear end of the crown of the inner water chamber C, the gases, &c:
being returned over the outer wall of such chamber toward the front of
the boiler and thence back again to the smoke stack. The combustion
and utilisation of the gases and products of combustion that pass from
the inner chamber B of the furnace to the outer chamber B¹ is effected

page_text: by the admission of air, which is broken up and subdivided into small
currents or minute quantities by means of numerous small perforations
e, e, made at or about the place where the great volume of flame and gases
pass from the inner furnace or preparing chamber into the outer or
combustion chamber. In a boiler or generator such as is shown in the
Drawing, such perforations are made in doors and front plates D. If the
flame and gases pass up at the back part of the furnace and over the top
of the water chamber C, the air may be admitted through a suitable box
placed just under the bridge wall and covered with fine wire gauze to
divide the air into numerous small currents or jets. In either case the
air thus admitted meets and is mixed with the unconsumed particles of
carbon when they are in a condition most favorable to receive such air,
and thereby ensures their utilisation and combustion, and converts the
watery vapors then existing into combustible carbonic gases or in other
words consumes the black smoke, which is nothing but the watery
vapors then not combustible mixed with the unconsumed particles of
carbon.
Figure 3 shows an application of my Invention to the ordinary upright
tubular boiler having water legs extending down on each side of the
fire chamber. Between such water legs a, a, and connecting therewith
and in or towards the upper part of the space ordinarily occupied by
the fire chamber is placed an arched shell two or three inches in width,
which makes the inner water chamber and which divides the fire
chamber into two parts, the lower one constituting the preparing, and
the upper one constituting the combustion chamber. Such arched shell
or inner water chamber is pierced and fitted with tubes as in the con-
struction first described, through which the products of combustion
pass from the preparing into the combustion chamber. From the top
of such inner water chamber pipes extend upward into the main
water chamber, so as to produce active and continual circulation of the
water between the two water chambers. Such pipes extend up to or
above the water line of the boiler, and are closed at their upper ends,
but have numerous openings in their sides at their upper ends, so
that as the water passes therefrom it will be discharged horizontally
in every direction against and amongst the hot-air tubes standing in
the water chamber, and thereby be more effectually converted into
steam.

page_text: 11 nay 10 статей аз лот 18,
1. The arrangement in combination with the main water chamber
of a boiler of an inner water chamber forming the shell of the fire
chamber, such inner and outer water chambers being connected together,
substantially as described.
2. The arrangement in combination with such an inner water chamber
forming the fire chamber of the fire tubes e, e, passing through such
water chamber, substantially as described.
3. Locating a portion of the water chamber of a boiler within the
furnace chamber, or between that part of the furnace where the coal
is burned and that part where the gases and products of combustion
are consumed, substantially as described.
4. The combination with a boiler consisting of two water chambers,
an inner and an outer connected together, of a furnace having two or a
preparing and combustion chamber, when the inner water chamber is
between the preparing and combustion chambers of the furnace, and
the combustion chamber of the furnace is between the inner and outer
water chambers.
5. The construction and arrangement, substantially as described, and
as shown in Figures 4 and 5, of the inner water chamber so as to
prevent the gases and products of combustion to pass into the outer or
combustion chamber in a volume or body substantially as and for the
purposes set forth.
6. In combination with such a construction of inner water chamber
as last-mentioned the arrangement of perforated plates for supplying
air in finely divided currents to the volume or mass of the gases and
products of combustion pass from the inner to the outer chamber of the
furnace.
7. In combination with the main or outer water chamber of an
upright boiler connecting the sides of such chamber by an arched
shell C¹ provided with discharge tubes c, such shell dividing the fire
chamber into two chambers, and forming an inner water chamber,
substantially as shown in Fig. 3 for the purposes set forth.
8. Constructing or forming the discharge water tubes of the inner
water chamber with side perforations at or near their upper ends, so as

page_text: to discharge the water therefrom horizontally for the purposes set
forth.
In witness whereof, I, the said Silas Covell Salisbury, have here-
unto set my hand and seal, this Fourth day of April, in the year
of our Lord 1870.
SILAS COVELL SALISBURY. (L.S.)
SILAS COVELL SALISBURY. (L.S.)