IMPROVEMENTS IN STEAM BOILERS
Year: 1877

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
STEAM BOILERS." A communication from abroad by René Constant Duchesne,
of Paris, in the Republic of France.
Sealed the 15th September 1877, and dated the 10th April 1877.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 10th April 1877.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN STEAM BOILERS." A communication from abroad
by René Constant Duchesne, of Paris, in the Republic of France.
This Invention relates to an improved steam boiler or generator, which is based
on the principle of the employment of an internal furnace arranged in such a
manner that the flame from such furnace, while acting powerfully for the heating of
the generator, may extend as far as to the smoke box, or to a collecting and distri-
buting chamber into which unignited gases evolved in one or more other furnaces
are conducted, the flame from which is distributed in tubes presenting a large
amount of heating surface.
By means of this arrangement the products of combustion, which have been
cooled by passing through tubes surrounded by the water in the boiler, when they
arrive at the smoke box or collecting and distributing chamber, become re-ignited
by the direct flame from the internal furnace, and all the products of the various
furnaces subsequently pass through tubes which present a large amount of heating
surface in order to reach the chimney, after transferring the greatest possible part
of their heat, either to the water in the boiler for the purpose of converting it into
steam, or to the steam in the said boiler to superheat it, or simultaneously to the
water and the steam for the purpose of converting the former into steam and super-
heating the latter.
This calorific capacity of ignited gases may be employed in various ways, the
object of the Invention being to re-ignite by means of the flame from one or more
furnaces the gaseous products of one or more other furnaces, the calorific capacity of
which has been utilized under favourable conditions by their passage through

page_text: numerous tubes passing through the boiler, and presenting a large amount of
heating surface, in such a manner that on re-igniting these products they may be
utilized simultaneously with those from the direct acting furnace or furnaces for
heating the water or the steam in the boiler while returning to the chimney through
tubes presenting a large amount of heating surface.
According to one mode of carrying out this Invention, three furnaces are em-
ployed, vizt., a central furnace and two side furnaces. The central furnace is direct
acting, and extends (of the same width throughout) to the smoke box or collecting
and distributing chainber, which is situate at one end, and is surrounded with the
water of the boiler. On the right and on the left respectively of the central furnace
are arranged the two other furnaces, the products of combustion from which are
conveyed into the same smoke box or chamber through two series of tubes. The
flame from the central furnace arriving without any impediment in the smoke box,
meets the gases from the two lateral furnaces therein, which have been divided by
passing through the two series of tubes herein-before referred to, and re-ignites
then, and the whole of the ignited gases are conveyed to the chimney, a portion of
such gases passing through a series of tubes leading direct from the smoke box or
chamber through the water space to the chimney, whilst the remainder pass through
another series of tubes arranged above the water level of the boiler, the ono part
being thus utilized for heating the water in the boiler, and the other part for drying
and superheating the steam which has been already generated.
The smoke box or chamber, which is made with a slightly flattened surface at its
upper part, may be strengthened by the addition of angle irons.
"
if preferred, the chimney, in lieu of being situate in front, may pass through the
steam dome, the peculiar forms and relative positions of the furnaces remaining the
same.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Scal Patent Office on the 9th
October 1877.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN STEAM BOILERS." A communication from abroad
by René Constant Duchesne, of Paris, in the Republic of France.
The said Invention, relating to improvements in steam boilers, consists in the
employment of an internal furnace or furnaces arranged in such a manner that the
flame from such furnace or furnaces, while acting powerfully for the heating of
the boiler, extends as far as to the sinoke box, or to a collecting or distributing
chamber into which are conducted unignited gases evolved in one or more other
furnaces, the flame from which is distributed in tubes having a large amount of
heating surface.
By means of this arrangement the products of combustion, which have been
cooled by passing through tubes surrounded by the water in the boiler, when they
arrive at the smoke box or collecting and distributing chamber, become re-ignited
by the direct flame from the internal furnace or furnaces, and the whole of the pro-
ducts of the various furnaces subsequently pass through tubes having a large
amount of heating surface on their way to the chimney, where they arrive after
having transferred the greatest possible part of their heat, either to the water in
the boiler for the purpose of converting it into steam, or to the steam in the said
boiler in order to superheat it, or simultaneously to the water and the steam for the
purpose of converting the former into steam and superheating the latter.
This calorific capacity of ignited gases may be employed in various ways, the
object of the Invention being to re-ignite by means of the flame from one or more
furnaces the gaseous products of one or more other furnaces, the calorific capacity
of which has been utilized under favourable conditions by such gaseous products

page_text: being conducted through multiple tubes passing through the boilor, and having a
large amount of heating surface, in such a manner that on re-igniting the said pro-
ducts they may be utilized simultaneously with those from the direct acting furnace
or furnaces for heating the water or the steam in the boiler while returning to the
chimney through another series of tubes, likewise having a large amount of heating
surface.
In carrying out the said Invention various arrangements may be adopted, but I
have shewn by way of example in the accompanying Sheet of Drawings one of those
which appears calculated to give good results in practice.
Figure 1 of the Drawings represents a central longitudinal section of a steam
boiler constructed according to the said Invention; and Figure 2 is a transverse
section of the same taken along the line 1, 2, (Figure 1).
In the arrangement shown in the Drawings three furnaces are employed, videlicet,
a central furnace and two side furnaces. The central furnace a is direct acting, and
extends (of the same width throughout) to a smoke box or collecting and distri-
buting chamber b. On the right and on the left respectively of the central furnace
there are arranged the two side furnaces c, c, the products of combustion from which
are conducted into the smoke box or chainber 6 through two series of tubes d, d.
The flame from the central furnace a, which enters the smoke box or chamber b
without any impediment, meets therein the gases from the two side furnaces c, c,
which have been divided by passing through the tubes d, d, and re-ignite such gases.
The whole of the ignited gases are then conducted to a chimney g, a portion of such
gases passing through a series of tubes e surrounded by the water in the boiler,
whilst the remaining portion passes through another series of tubes f arranged
above the water level of thic boiler; the one portion is thus utilized for heating the
water in the boiler, and the other portion for drying and superheating the steam
which has been aleady generated.
The Invention, whilst enabling a convenient water level to be obtained, admits of
a simple and substantial construction of boiler; for example, in the arrangement
shown in the Drawings the three furnaces may be readily connected with each other,
and the smoke box or chamber may be connected with the end of the boiler by
means of suitable stay h.; and in other modifications, of which the system is suscep-
tible, similar facilities are afforded.
The smoke box or chamber, which is made with a slightly flattened surface at its
upper part, may be readily strengthened, as shown in the Drawing, by the addition
of angle irons i.
The furnace doors, the man-holes, and fire-bridges are constructed in a similar
manner to those of ordinary carefully constructed boilers.
If desired, the chimney, in lieu of being situate in front, may pass through a
steam dome, the peculiar forms and relative positions of the furnaces remaining the
same,
The form of the parts and the accessory arrangements may also be variously
modified, whilst retaining the principle of the Invention.
Having now described and particularly ascertained the nature of the said In-
vention, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original, and
therefor claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,-
First. Constructing boilers with two or more furnaces arranged in their interior
in such a manner that the flame from one or more of the furnaces on entering a
smoke box or collecting and distributing chamber shall be caused to meet and ignite
the gascous products of combustion from another furnace or furnaces, which pro-
ducts have been cooled by being utilized in passing through a series of tubes, the
whole of the products of combustion in the said smoke box or collecting and distri-
buting chamber being thence conducted to the chimney through another series of
tubes for the purpose of further utilizing the heat contained in such products, sub-
stantially as herein-before described.

page_text: Secondly. The combination in a steam boiler of three internal furnaces, one with
a direct acting, flame, and the others with series of tubes inside the boiler conducting
the products of the furnaces to a rear chamber, where they are re-ignited, the united
products of the three furnaces being subsequently caused to pass through another
series of tubes surrounded by the water in the boiler and by the steam on their way
to the chimney, where they escape after having transmitted the greatest possible
amount of heat during their passage, substantially as herein-before described and
illustrated by the accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my Speci
fication set my hand and seal, this Ninth day of October, One thousand
eight hundred and seventy-seven.
J. HENRY JOHNSON. (L.S.)