IMPROVEMENTS IN STEAM GENERATORS
Year: 1881

page_text: LETTERS PATENT to Benjamin Brazelle, of Saint Louis, in the County of
Saint Louis, State of Missouri and United States of America, Engineer, for
an Invention of "IMPROVEMENTS IN STEAM GENERATORS."
PROVISIONAL SPECIFICATION left by the said Benjamin Brazelle at the
Office of the Commissioners of Patents on the 26th April 1881.
;
BENJAMIN BRAZELLE, of Saint Louis, in the County of Saint Louis, State of
Missouri and United States of America, Engineer. "IMPROVEMENTS IN STEAM
GENERATORS."
The object of the Invention is to provide a steam generator of strong and simple
construction, in the operation of which a constant, rapid, and thorough circulation
of water shall be effected, the volume of contained water relatively to a given
amount of heating surface be reduced, the tendency to foaming be diminished, and
the production of drier steam correspondingly ensured, and the economization of
fuel be promoted by the utilization, as far as may be, of the heat of the escaping
products of combustion.. To this end the improvements consist.in the combination
of a cylindrical shell, closed at both ends, and adapted to be located above a
furnace, a fire tube or tubes traversing said shell, and a steam receptacle located
within the shell. below the water levél; also, in the combination with a cylindrical
shell having closed ends of a series of fire tubes traversing said shell, a steam
chamber located within said shell below the water level, and a series of water
tubes; also in the combination with a furnace having an upwardly projecting
throat or outlet for the products of combustion of a vertical shell enclosing
steam and water receptacles, a fire tube or tubes traversing said shell, and a
return flue or flues opening into the furnace below the level of the 'throat or
outlet.

page_text: SPECIFICATION in pursuance of the conditions of the Letters. Patent, and
of an Order of the Lord Chancellor, filed by the said Benjamin Brazelle in
the Great Seal Patent Office on the 4th November 1881.
BENJAMIN BRAZELLE, of Saint Louis, in the County of Saint Louis, State of
Missouri and United States of America, Engineer. "IMPROVEMENTS IN STEAM
GENERATORS."
The object of my Invention is to provide a steam-generator of strong and simple
construction, in the operation of which a constant rapid and thorough circulation
of water shall be effected, the volume of contained water relatively to a given
amount of heating surface be reduced, the tendency to foaming be diminished, and
the production of drier steam correspondingly insured, and the economization of
fuel be promoted by the utilization as far as may be of the heat of the escaping
products of combustion.
To this end my improvements consist in the combination of a cylindrical shell
closed at both ends and adapted to be located above a furnace, a fire tube or tubes
traversing said shell, and a steam-receptacle located within the shell below the
water-level; also in the combination with a cylindrical shell having closed ends of
a series of fire-tubes traversing said shell, a steam-chamber located within said
shell below the water-level, and a series of water tubes; also in the combination
with a furnace having an upwardly-projecting throat or outlet for the products of
combustion of a vertical shell inclosing steam and water receptacles, a fire tube or
tubes traversing said shell, and a return flue or flues opening into the furnace below
the level of its throat or outlet. The improvements claimed are hereinafter more
fully set forth.
In the accompanying Drawings, Figure 1 is a vertical central section through a
steam-generator embodying my improvements; Fig. 2, a horizontal section on
an enlarged scale through the same at the line x, x, of Fig. 1; Fig. 3, a vertical
central section through the furnace taken at right angles to Fig. 1; Fig. 4, a view
in elevation of the same; Fig. 5, a plan view of the same with the ash-pit door in
section; Fig. 6, a horizontal section through the furnace-casing at the center of
the fire-door; Figs. 7 & 8, vertical central sections showing modified forms of
my improvements; and Figs. 9 and 10, horizontal sections through the same at the
lines y, y, of Fig. 8, and 2, 2, of Fig. 9 respectively. To carry out my Invention I
provide a cylindrical shell A of iron or steel plate which is closed at top and
bottom by flanged heads a, a¹, the lower of which, a', is preferably placed a short
distance above the lower end of the shell, as in Figs. 1 and 8, to form a combustion-
chamber, and in such case is usually connected to an inner ring a², which is united
at bottom to the shell by a bar or a plate of -section in the ordinary manner.
The shell A is located above and supported upon a cylindrical furnace B provided
with a grate b, fire-door b¹, ash-pit ba, and ash-pit door 63, and having a suitable
lining of fire-brick or other non conducting inaterial. The heads a and a¹ are
connected by a series of fire-tubes a³, through which the products of combustion
pass to the uptake a¹¹, to which is connected an exit-flue at provided with a
damper a Flanged circular heads a, a, are riveted to and inade steam-tight
with the shell A between the heads a, a', thereby dividing the shell into an upper
and a lower water-chamber, the upper portion of the former constituting a steam-
space, as in the ordinary vertical tubular boiler and the space between the
heads a, a, less that portion thereof which is occupied by the tubes, forming
separate steam-chamber A' below the normal water-line of the generator, said
chamber communicating with the steam-space A in the upper water-chamber
above the water-line by a central steam-pipe as, which is open at both ends and
passes steam-tight through the upper head as of the steam-chamber A¹ from a
point near the top of the steam-space A2 to the lower portion of the chamber A¹.
a

page_text: The heads a, a, of the steam-chamber A¹ are connected by a series of
water-tubes, each surrounding and concentric with one of the fire-tubes a³,
so that an annular water-space is formed between each fire-tube and its encircling
water-tube, and a series of return water-tubes a connects the heads a, a, the
return-tubes being arranged in a circle about the series of fire-tubes and between
the same and the shell A. A pipe A³ connected to the shell at the upper portion
of the steam-space A2, and below the lower head ², serves for the attachment of
a glass water-gage A*, steam-gage A', and gage-cocks. Steam is supplied to the
engine from a pipe A communicating by connections A', As with the steam-space A²
and steam-chamber A', and furnished with a valve or cock A, by means of which
steam may be taken from either receptacle as desired. A suitable safety-valve A
is connected to the pipe A and pipes A", A" are connected to the lower portion of
the shell for the attachment respectively of check and blow-off valves for the
supply and discharge of water to and from the generator. In the modifications
shown in Figs. 7 to 10 inclusive the internal steam-chamber A' is an annular vessel
located within the water-space aud surrounding a single fire-tube, Figs. 7 and 9, or
a series of fire-tubes, Figs. 8 and 10, and having a free circulation of water around,
above, and below it, the water passing downward on its outer and upward on its
inner side, as indicated by the arrows. The vessel A' is closed at top and open at
bottom, and its outer wall projects downwardly below the inner, forming a
deflecting-ring, which is interposed between the opening of the chamber and the
downwardly-moving currents of water between the exterior thereof and the shell.
The steam from the chamber A¹ passes out continuously under the edge of the
shorter inner wall to the steam-space A2, whence it is supplied to the engine, and
its place is supplied by accretions of steam generated from the water passing
around and under the outer wall. My improvements, so far as hereinbefore set
forth, are capable of use with a furnace of the ordinary description and a direct
draft, but are especially designed and adapted for the greater economization of fuel
by their combination with means for utilizing heat, which would otherwise pass
directly from the upper ends of the fire-tubes to the chimney. To this end I provide
a circular throat or outlet B1 for the products of combustion, said throat extending
up to or slightly above the bottom of the shell A and communicating through the
combustion-chamber at the lower end of the shell with an annular passage B²
surrounding the throat, said passage being connected by a return flue or flues B³
with the uptake a¹ The connection of the return-flue B3 with the passage B
must be below the top or opening of the throat B', which requirement will be
answered either by extending the throat upwardly, as in Figs. 7 and 8, or by
forming a downward extension of the shell or its botton water-space ring, as in
Fig. 1. A series of arms or projections in the passage B radiating from the central
throat supports the generator in proper relation to the throat B without
interrupting communication between the throat, the annular passage, and the
return-flues. The return-flues B³ may be either within or external to the sheil A,
as preferred, and in Figs. 1 and 2 a single annular return-flue is shown, the same
being formed between the shell and a concentric cylindrical casing. B* connected_at
top to the uptake a" and at bottom to the periphery of the annular passage B².
In Figs, 7 to 10 inclusive a series of tubular return-flues is arranged within the
shell A extending from one head thereof to the other similarly to the direct-draft
fire-tubes. In operation a constant and rapid circulation is induced by the action
of the heat upon the water in the annular spaces surrounding the fire-tubes A, the
currents ascending through said spaces and descending through the return
water-tubes aº. The steam generated passes into the upper steam-space A² and
thence through the pipe as into the steam-chamber A¹, in which it will be seen it
is entirely out of contact with the water and is further subjected to the
superheating action of the return flue or flues B³. In addition to the provision of
superior facilities for circulation a capacious reservoir of dry steam is substituted
for the unduly large water-space existing in vertical tubular boilers of the ordinary
construction, materially reducing the volume of contained water as compared

page_text: 'therewith and correspondingly facilitating the free and rapid generation of steam.
The thorough circulation also prevents accumulation of scale or deposit in the
tubes and the provision of a separate steam-chamber effectually obviates foaming,
even with an exceptionally high water-level. The effect of the upwardly-
projecting throat of the furnace in connection with the surrounding annular
passage is to create an upward draft through said passage, inducing a downward.
draft through the return-flues which open thereinto and correspondingly rendering
available the heat of products of combustion which would otherwise escape.
unutilized into the chimney.
I claim as my Invention, and desire to secure by Letters Patent,-
1. The combination in a steam-generator of a cylindrical shell closed at both
ends, a fire tube or tubes traversing said shell, and a-steam-receptacle located within
the shell and surrounding the fire tube or tubes below the water-level, substantially.
as set forth.
2. The combination in a steain-generator of a cylindrical closed-ended shell, a
series of fire-tubes traversing said shell, a steam-chamber located within said shell
below the water-linė, and a series of water-tubes traversing said steam-chamber,"
substantially as set forth."
3. The combination in a steam-generator of an upper and a lower water-chamber,
a series of fire-tubes traversing said chambers, a series of water-tubes connecting
said chambers, each forming an annular water-passage around one of the
fire-tubes, and a series of return water-tubes, each presenting its entire cross
section for the passage of water from one to the other chamber, substantially as set
forth.
:
t
4. The combination in a steam-generator of a cylindrical closed-ended shell, a
steam-chamber having its upper and lower walls formed by two flanged heads
secured to the shell below the water-level, a series of fire-tubes connecting 'the
heads of the cylindrical shell, a series of water-tubes connecting the heads
of the steam-chamber, each surrounding one of the fire-tubes and presenting
an annular section for the passage of water, a series of return-tubes connecting 'the
heads of the steam-chamber, each open through its entire extent for the passage of
water, and a pipe establishing communication between the steam-chamber and the
steam-space above its upper head, substantially as set forth.
'
5. The combination in a steam-generator of a furnace having an upwardly-
*projecting throat or outlet for the products of combustion, a vertical shell inclosing
steam and water receptacles and located above said furnace, a fire-tube or tubes
traversing said shell, and a return flue or flues communicating with the fire-tubes
around the throat of the furnace and below the upper level thereof, substantially as
set forth.
6. The combination in a steam-generator of a vertical shell having a series of
direct-draft fire-tubes, and an internal steam-chamber located 'below the water-line,
'a return-flue surrounding said internal steam-chamber, a furnace having an
upwardly-projecting throat or outlet for the products of combustion, and an
annular passage connecting the direct-draft tubes and return-flue around the
throat of the furnace and below the upper level thereof, substantially as set
'forth.
In witness whereof, I, the said Benjamin Brazelle, have hereunto set my
Witnesses,
A. W. TEMPLE.
GEO. H. 'BARRUS.
BENJAMIN BRAZELLE., (L.S.)