Improvements in Marine and other High Pressure Steam Boilers.
Year: 1888

page_text: Date of Application, 1st Aug., 1888
Complete Specification Left, 1st May, 1889-Accepted, 15th June, 1889
PROVISIONAL SPECIFICATION.
Improvements in Marine and other High Pressure Steam Boilers.
I, GEORGE FREDERICK REDFERN, of the firm of G. F. Redfern & Co., the General
Patent Office, No. 4 South Street, Finsbury, in the County of Middlesex, Patent
Agents, io hereby declare the nature of this invention (a communication from
abroad by Alexandre Lagrafel and Jules d'Allest, both of Marseilles, in the republic
of France, Engineers) to be as follows:-
The change which has been effected during the last two or three years in marine
steam boilers which consists in the employment of steam at pressures varying from
12 to 15 K expanding successively into three or four cylinders, necessitates the
abandonment of cylindrical boilers with interior furnaces as hitherto employed as
owing to their large dimensions and the high pressure to which they are
subjected they cannot be so strongly plated as to enable them to withstand such high
pressures.
This invention relates to the construction of a kind of tubular boiler especially
adapted to allow of the employment of high pressures, certain very important
modifications being made to ensure a perfect combustion which up to the present has
not been attained with steam boilers of this construction.
It is well known that with steam boilers of this construction the ignited gases
produced on the furnace bars by the combustion of the coal rise vertically and come
in contact with a very large tubular surface which quickly cools and extinguishes
them; under these conditions the carbonic oxide which is produced on the surface of
the coal and which only burns above the furnace bars and the volatile carburets which
are disengaged fróin fresh coal when the furnace is charged fall below their
temperature of combustion, and escape through the chimney carrying away their heat
of combustion and imparting only their specific heat to the water in the boiler ;
further, the gases rising vertically mix badly with the air, the effect of which is also
to prevent complete combustion even if the flame is not extinguished too soon.
On the other hand it is well known that in the ordinary marine steam boiler which
bas an internal furnace fire box and return flues for the flame the combustion is
perfect; the furnace does not present large cooling surfaces, the presence of the
bridge and of the fire box ensures the mixture of the gases by forcing the flame to
reverberate and the cluster of return tubes takes up the whole of the heat contained
in the products of combustion after the combustion is completed.
The improved boiler which forms the subject of this invention is so constructed as
to obtain the same results.
Each boiler is constructed with a cluster of tubes for a current of water to circulate
in, and connecting two prismatic boxes firmly stayed and forming the front and back
of the boilers.
These boxes communicate with a cylinder placed at their upper part in which the
level of the water is maintained and which forms a receptacle for the steam.
The tubes arranged in rectilinear rows are inclined to the horizon sufficiently to
allow of water circulating through them; this circulation is effected through the
prismatic boxes and the cylinder.
The novel and principal feature of the invention consists in the construction of
the furnace.
Each furnace grate is placed beneath the first row of tubes which is covered with
bricks and forms the crown of the furnace; the gases of combustion produced on the
grate pass over a bridge and into a combustion chamber formed between the tubes ;
the flames or the extinguished gases then return through a serios of upper tubes
(the last row of which is also covered with bricks) and pass into a suioke box

page_text: and thence escape through a chimney after having heated the lower part of the
steam cylinder.
In cases where two boilers are connected together the fire box is common to both
boilers; its lower part is provided with a number of tubes for taking up the heat
radiating from the flame; by this arrangement when the furnace is charged the gases
first generated are mixed with and burned by the hotter gases from the grate directly
they meet in the fire box.
In the case of a single boiler the vertical side of the fire box is closed by one or
two rows of tubes. The grate can be arranged in two different ways, that is to say,
either parallelwise or perpendicularly to the tubes; in the first case the furnace doors
are made in the prismatic front of the boiler; in the second case they are at the
sides the ash-pit dampers are placed below. This arrangement of grate furnace
and fire box can be adapted to all boilers of the class to which this invention relates.
The tubes covered with bricks to form the crown of the furnace and the cluster of
tubes) and the rows of tubes, in the case where a single boiler is employed, can be
replaced by water spaces well stayed for forming a communication between the
prismatic boxes.
By these improvements consisting in the employment of a furnace having a bridge,
of a combustion chamber and of a return passage consisting of a cluster of tubes the
conditions of combustion and of circulation of the gases which have been obtained
with ordinary cylindrical marine steam boilers can be attained with tubular boilers.
This arrangement which has never been employed with boilers of the kind to
which it is now proposed to adapt it ensures a total combustion of the gases issuing
from the coal and a complete taking up of the heat which it contains whereby a boiler
is obtained well adapted to support high pressures of 15 atmospheres and above and
further effecting as perfect a ultilization of the fuel as is obtained with ordinary steam
boilers.
G. F. REDFERN & Co,
4, South Street, Finsbury, Londo... Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Marine and other High Pressure Steam Boilers.
I, GEORGE FREDERICK REDFERN, of the firm of G. F. Redfern & Co., the General
Patent Office, No. 4, South Street, Finsbury, in the county of Middlesex, Patent
Agents do hereby declare the nature of this invention (a communication from abroad
by Alexandre Lagrafel and Jules d'Allest both of Marseilles in the Republic of
France, Engineers) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The change which has been effected during the last two or three years in marine
steam boilers which consists in the employment of steam at pressures varying from
12 to 15 K expanding successively into three or four cylinders, necessitates the
abandonment of cylindrical boilers with interior furnaces as hitherto employed as
owing to their large dimensions and the high pressure to which they are
subjected, they cannot be so strongly plated as to enable them to withstand such high
pressures.
This invention relates to the construction of a kind of tubular boiler especially
adapted to allow of the employment of high pressures, certain very important
modifications being made to ensure a perfect combustion, which up to the present has
not been attained with steam boilers of this construction.
It is well known that with steam boilers of this construction, the ignited gases
produced on the furnace bars by the combustion of the coal, rise vertically and
come in contact with a very large tubular surface which quickly cools and extinguishes
them under these conditions the carbonic oxide which is produced on the surface of
the coal and which only burns above the furnace bars and the volatile carburets which

page_text: are disengaged from fresh coal when the furnace 15 charged fall below their
temperature of combustion, and escape through the chimney carrying away their
heat of combustion and imparting only their specific heat to the water in the boiler:
further, the gases rising vertically, mix badly with the air, the effect of which is also
to prevent complete combustion even if the flame is not extinguished too soon. .
On the other hand, it is well known that in the ordinary marine steam boiler which
has an internal furnace, fire box and return flues for the flame, the combustion is
perfect; the furnace does not present large cooling surfaces, the presence of the
bridge and of the fire box ensures the mixture of the gases, by forcing the flame to
reverberate, and the cluster of return tubes takes up the whole of the heat contained
in the products of combustion after the combustion is completed.
The improved boiler, which forms the subject of this invention is so constructed as
to obtain the same results.
Each boiler is constructed with a cluster of tubos, for a current of water to circulate
in, and connecting two prismatic boxes A and B firmly stayed and forming the front
and back of the boilers.
These boxes communicate with a cylinder placed at their upper part, in which
the level of the water is maintained and which forms a receptacle for the steam.
The tubes arranged in rectilinear rows are inclined to the horizon sufficiently to
allow of water circulating through them; this circulation is effected through the
prismatic boxes A, B and the cylinder C.
The novel and principal feature of the invention, consists in the construction of
the furnace.
Each furnace grate D is placed beneath the first row of tubes E which is covered
with bricks and forms the crown of the furnace; the gases of combustion produced
on the grate D, pass over a bridge F and into a combustion chamber G, formed
between the tubes; the flames or the extinguished gases then return through a series
of upper tubes (the last row of which is also covered with bricks) and pass in the
direction of the arrow H, into a smoke box I and thence escape through a
chimney K, after having heated the lower part of the steam cylinder C.
In cases where two boilers are connected together, as illustrated in Figures 1, 2
and 3, the combustion chamber G is common to both boilers; its lower part is
provided with a number of tubes L for taking up the heat radiating from the flame;
by this arrangement, when the furnace D is charged, the gases first generated are
mixed with and burned by the hotter gases from the grate B', directly they meet in
the fire box.
In the case of a single boiler, as illustrated in figures 4 and 5, the vertical side of
the fire box is closed by one or two rows of tubes N. The grate can be arranged in
two different ways, that is to say, either parallel with the tubes, as shewn in figures
1, 2 and 3 or perpendicularly to the tubes, as shown in figures 4 and 5; in the first
case, the furnace doors are made at M in the prismatic front of the boiler; in the
second case, they are at the sides; the ash pit doors which can be made of a relatively
very large size are placed below. This arrangement of grate furnace and fire box
can be adapted to all boilers of the class to which this invention relates.
The tubes E and E, covered with bricks to form the crown of the furnace and
the cluster of tubes, and the rows of tubes N, in the case where a single boiler is
employed, can be replaced by water spaces well stayed for forming a communication
between the prismatic boxes, as shewn in figure 5.
By these improvements consisting in the employment of a furnace having a
bridge, of a combustion chamber and of a return passage, consisting of a cluster of
tubes, the conditions of combustion and of circulation of the gases which have been
obtained with ordinary cylindrical marine steam boilers can be attained with tubular
boilers.
This arrangement which has never been employed with boilers of the kind to
which it is now proposed to adapt it, ensures a total combustion of the gases issuing
from the coal and a complete taking up of the heat which it contains whereby a boiler
is obtained well adapted to support high pressures of 15 atmospheres and above and

page_text: further effecting, as perfect
steam boilers.
utilization of the fuel as is obtained with ordinary
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
The improvements in marine and other high pressure steam boilers substantially as
hereinbefore described with reference to the accompanying drawings.
Dated the 1st use of May 1880
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.