Year: 1886

page_text: Date of Application, 11th Dec., 1886
Complete Left, 8th Sept., 1887.
Complete Accepted, 11th Oct., 1887.
I, MATTHEW MURRAY JACKSON, of No. 47 Norton Road, Brighton in the County
of Sussex, Engineer, do hereby declare the nature of this invention to be as
follows:-
In the construction of steam boiler now more particularly used for marine engines
a cylindrical shell of large diameter and comparatively short length contains in its
lower part the furnace and in its upper part the fire tubes through which the flames
and combustion gases pass forward after leaving the back end of the fire tube and
furnace chamber in the lower part, and the necessary steam space requiring also to be
left above the fire tubes. The large diameter of boiler shell necessitated by this
construction renders it impossible to employ very high pressures with safety with
ordinary thicknesses of plate, while the use of thick plates for resisting higher
pressures not only entails structural inconveniences but causes insecurity owing to
the fact that thick plates are not so perfect and trustworthy as thinner plates.
According to my present invention, I obviate these defects by employing in place of
a single large cylindrical shell containing the furnace, the fire tubes and the steam
space as above described two separate cylindrical shells situated one above the other,
the lower one of which contains the furnace only, while the upper one only contains
the fire tubes and steam space, the water spaces of the two shells being suitably con-
nected by tubes so as to ensure an effectual circulation of the water. By thus using
two shells of reduced and moderate diameter I am enabled to construct boilers that
will effectually withstand the high pressures now generally required, with the ordinary
perfectly safe moderate thickness of plate. I construct such boilers either single or
double, that is to say, with two boilers placed end to end with a combustion chamber
between them and the furnace being fired at each outer end, as in boilers of present
construction. In this case the two boilers may either be complete in themselves,
their inner ends being a sufficient distance apart to form the combustion chamber
between them, this space being enclosed by a sheet metal casing lined with fire clay
and formed to fit closely between the upper and lower shells of each boiler. The
bottom of the combustion chamber is formed by a hollow box on which is placed the

page_text: fire bridge common to two furnaces, and the top of the combustion chamber is by
preference formed with a flat arch reaching above the top rows of the fire tubes.
The upper and lower shells of each boiler are connected together by a short vertical
connecting tube of large diameter at about the middle of their lengths; or there may
be two or more such connections.
According to another arrangement instead of constructing the double compound
boilers as two separate boilers, I construct a single upper and lower shell of a length
equal to the combined length of two boilers.
The two shells are connected together at their middle by a vertical cylinder, and
through this connection passes a fire flue or uptake connecting two combustion
chambers, one in the lower and the other in the upper shell. The lower combustion
chamber receives the furnace and contains the fire bridge, while the upper one is
reserved for the fire tubes, and forms the tube plates for the inner ends of the two sets
thereof.
According to another modification of this araangement, instead of passing the flue
or uptake through the vertical or connecting cylinder between the upper and lower
shells I construct the upper shell with its combustion chamber separate from the lower
shell with its combustion chamber, I enclose the space between the opposite openings
of the two combustion chambers with a sheet iron enclosure lined with fire clay, so as
to form a continuous uptake or combustion chamber, and I establish connections
between the water spaces of the two parts by means of two connecting tubes, one on
each side of the combustion chamber.
In applying my invention to single boilers, I connect the back end of the furnace
of the lower shell with the back tube plate of the upper shell by means of an enclosing
casing lined with fire clay to constitute the combustion chamber, which may be sup-
ported on a hollow iron box as in the first described arrangement. Two or more of these
single boilers may be arranged side by side, with their combustion chambers joining
on to each other at their back ends.
When a forced draught and a closed ash pit are employed, a current of air may be
admitted through the said hollow box, at the bottom of the combustion chamber, so as
to issue through the passages formed below the fire bridge and under the grate. The
furnace may in either of the above cases be made of corrugated instead of plain
cylindrical plates.
In some cases instead of constructing my improved steam boiler with two shells as
described, I employ in place of the one lower shell, two such, of proportionately smaller
diameter, each containing a furnace and each having their water spaces connected to
a single upper shell by the connecting tubes before described, and, if necessary,
having their water spaces connected with each other as well as with the upper shell.
Dated this 11th day of December 1886.
also

page_text: I, MATTHEW MURRAY JACKSON of No. 47 Norton Road, Brighton in the County of
Sussex, Engineer do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement:-
In the construction of steam boiler now more particularly used for marine engines
a cylindrical shell of large diameter and comparatively short length contains in its
lower part the furnace and in its upper part the fire tubes through which the flames
and combustion gases pass forward after leaving the back end of the fire-tube and
furnace chamber in the lower part, and the necessary steam space requiring also to
be left above the fire tubes. The large diameter of boiler shell necessitated by this
construction renders it impossible to employ very high pressures with safety
with ordinary thicknesses of plate while the use of thicker plates for resisting
higher pressures not only entails structural inconveniences but causes insecurity
owing to the fact that thick plates are not so perfect and trustworthy as thinner
plates.
My present invention relates to a construction of boiler in which these difficulties
are obviated by employing in place of a single large cylindrical shell containing the
furnace, the fire tubes and the steam space as above described two separate cylindrical
shells situated one above the other, the lower one of which contains the furnace only,
while the upper one only contains the fire tubes and steam space, the water spaces of
the two shells being suitably connected by tubes so as to ensure an effectual circulation
of the water, while the furnace or furnaces of the lower shell is or are connected to
the fire tubes of the upper shell by a combustion chamber at the one end, constructed
separate from the shells. By thus using two shells of reduced and moderate diameter
I am enabled to construct boilers that will effectually withstand the high pressures
now generally required with the ordinary perfectly safe moderate thickness of plate.
1 construct such boilers either single or double, that is to say, with two boilers placed
end to end with a combustion chamber between them and the furnace being fired at
each outer end as in boilers of present construction. In this case the two boilers may
either be complete in themselves, their inner ends being a sufficient distance apart to
form the combustion chamber between them, this space being enclosed by a sheet
metal casing lined with fire clay and formed to fit closely between the upper and

page_text: lower shells of each boiler. The bottom of the combustion chamber is formed by a
hollow box on which is placed the fire bridge common to two furnaces and the top of
the combustion chamber is by preference formed with a flat arch reaching above the
top rows of the fire tubes.
The upper and lower shells of each boiler are connected together by a short vertical
connecting tube of large diameter at about the middle of their lengths; or there may
be two or more such connections.
According to another arrangement instead of constructing the double compound
boilers as two separate boilers, I construct a single upper and lower shell of a length
equal to the combined length of two boilers.
The two shells are connected together at their middle by a vertical cylinder, and
through this connection passes a fire flue or uptake connecting two combustion
chambers, one in the lower and the other in the upper shell. The lower combustion
chamber receives the furnace and contains the fire bridge, while the upper one is
reserved for the fire tubes, and forms the tube plates for the inner ends of the two sets
thereof.
'
According to another modification of this arrangement, instead of passing the flue
or uptake through the vertical or connecting cylinder between the upper and lower
shells I construct the upper shell with its combustion chamber separate from the lower
shell with its combustion chamber. I enclose the space between the opposite openings
of the two combustion chambers with a sheet iron enclosure lined with fire clay so as
to form a continuous uptake or combustion chamber, and I establish connections
between the water spaces of the two parts by means of two connecting tubes, one on
each side of the combustion chambers.
In applying my invention to single boilers, I connect the back end of the furnace
of the lower shell with the back tube plate of the upper shell by means of an enclosing
casing lined with fire clay to constitute the combustion chamber, which may be
supported on a hollow iron box as in the first described arrangement. Two or more
of these single boilers may be arranged side by side, with their combustion chambers
joining on to each other at their back ends.
When a forced draught and a closed ash pit are employed, a current of air may be
admitted through the said hollow box, at the bottom of the combustion chamber so as
to issue through passages formed below the fire bridge and under the grate. The
furnace may in either of the above cases be made of corrugated instead of plain
cylindrical plates.
In some cases instead of constructing my improved steam boiler with two shells as
described, I employ in place of the one lower shell two such of proportionately smaller
diameter, each containing a furnace and having their water spaces connected to a
single upper shell by the connecting tubes before described, and, if necessary, also
having their water spaces connected with each other as well as with the upper
shell.
Fig. 1 of the accompanying drawings shews a longitudinal section of two boilers
constructed according to my above described invention, arranged back to back, and
Fig. 2 shews a cross section through the combustion chamber. A A are the lower
cylindrical shells containing the furnaces B, and A' A' are the upper shells containing
the fire tubes C and the steam spaces, the parts A¹ A¹ being connected together by
cylindrical connecting pieces DD. The space left between the inner ends of the
two boilers is formed into a combustion chamber E through which the flames and
combustion gases pass from the furnace B to the fire tubes C and thence to the
uptake F.
The combustion chamber E is constructed entirely independently of the boiler,
being formed of a hollow iron or steel box G at bottom which supports a casing H
slightly arched at top and lined with fire brick, enclosing the sides and top of the
space. When a forced draft is used the box G may with advantage serve for the
introduction of the air beneath the furnace grates, for which purpose it is connected
with the blowing apparatus at the one end, and is formed with suitable openings

page_text: below the grate bars for the issue of the air. Upon the top of the box G is formed
the fire brick bridge 1 serving for the furnaces of both boilers.
The joints of the combustion chamber with the circular surfaces of the boilers are
made air tight by fireclay or other suitable means.
Figs. 3, 4 and 5 shew respectively a cross section a part longitudinal section and
a sectional plan of a modification of the above described construction in which the
sides and top of the casing H are formed hollow so as to constitute a chamber through
which the whole of the feed water for the boilers is made to pass; the water being
supplied by pumps through an opening at K and being drawn off through an opening
at K¹ and forced into the boilers by a feed pump or other arrangement. A raised
partition I is provided at top over which the water overflows so as to insure that a
sufficient depth of water shall always be maintained over the top of the fire chamber.
The feed heater thus constructed is not subject to any internal pressure. The boiler
is otherwise constructed the same as above described.
.
Figs. 6, 7 and 8 shew respectively a cross section, a longitudinal section and a part
plan of a single boiler constructed as first described, the parts being indicated by the
same letters of reference.
Figs. 9, 10 and 11 shew respectively an end view, a part sectional plan and a side
view of a group of three boilers constructed as above described, having a combustion
chamber divided into three separate compartments by partitions. Fig. 12 shews a
cross section of two boilers side by side, each of which has two lower shells A A
containing the furnaces, connected by cylindrical connecting pieces D to one upper
shell A¹ containing the fire tubes.
Figs. 13, 14 and 15 shew respectively a longitudinal section and a transverse section
and a part cross section through the combustion chamber in which, instead of forming
two separate boilers with a separate combustion chamber between them as first
described, a single boiler of about double length has a combustion chamber E formed
at its middle, which passes up from the lower shell A through the central cylindrical
connection D¹ into the upper shell A¹ where it forms the inner tube plates to the two
sets of tubes C C. The fire brick bridge I to the two sets of furnaces is supported
upon the lower part of the combustion chamber. D D are cylindrical connections for
connecting the water spaces of A and A¹ in addition to the connection D'.
Figs. 16, 17 and 18 shew respectively a part sectional elevation part cross section
and part sectional plan of another modification of the last described arrangement in
which, instead of carrying the combustion chamber E through a cylindrical connection
of the shells A and A¹, the parts of the combustion chamber in each shell are made
separate from each other, and are made to communicate by means of a rectangular
connecting piece M lined with fire clay, which is made in halves bolted together, as
shewn, so as to allow of its being fixed in position between the two shells, these being
connected by the cylindrical connections D D as before.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed I declare that what I claim is :-
1. Constructing steam boilers of two cylindrical shells arranged one above the
other, the lower one containing the fire grate and the upper one the fire tubes, the
water spaces of the two shells being connected together at one or more points of their
length by a connecting tube or tubes, while the inner ends of both shells are made to
communicate with a separately constructed combustion chamber through which the
flames and combustion gases rise from the furnace in the lower shell to the fire tubes
of the upper shell, substantially as herein described with reference to Figs. 1 to 12 of
the drawings.
2. In steam boilers constructed as set forth in the preceding claim, arranging two
or more such boilers back to back with a space between them in which is situated a
separately constructed combustion chamber common to both or all substantially as
herein described.
3. In steam boilers constructed as set forth in the preceding claims forming the

page_text: bottom part of the separate combustion chamber as a hollow box through which the
forced air supply to the furnace is made to pass, substantially as herein described
with reference to Figs. 1 to 5 of the drawings.
4. Constructing steam boilers of a lower cylindrical shell containing the furnaces
and an upper cylindrical shell containing the fire tubes and steam space, the two shells
being connected by a central connecting tube for the water spaces, and a central
combustion chamber, extending from the furnace tubes in the lower shell up to the
fire tubes of the upper shell, substantially as herein described with reference to Figs. 13
to 15 of the drawings.