Improvements in Cylindrical Marine Boilers.
Year: 1899

page_text: Date of Application, 1st Nov., 1899
PROVISIONAL SPECIFICATION.
Improvements in Cylindrical Marine Boilers.
I, FRANCIS DRAKE, 157, Fenchurch Street, London, E.C., Marine Engineer, do
hereby declare the nature of this invention to be as follows:-
My within invention relates more particularly to the class of cylindrical marine
boilers to be employed on board screw, or paddle steamers, and my object is to
provide a boiler which will give a greater strength to the internal parts, and
give a greater heating surface, & better combustion, and cause a greater circula-
tion of the water throughout, & also to reduce the quantity of water to be used in
the boiler, as against the ordinary multitublar boiler now in use.
In order that my invention may be more clearly understood, reference is had
to the accompanying drawings, which show central vertical_sections, and horizontal
sections, of so much of a cylindrical marine boiler, constructed according to my
invention as is needful to an understanding of my improvements.
As shown in (Figs. 1, & 2,) the saddle plates and combustion chambers are
returned over the crowns of the furnaces, for a sufficient distance to allow of one,
or more diagonal water tubes being fitted between the saddle plates and the
crown of the combustion chambers, the longitudinal fire tubes are thus shortened,
altho' this method does not contract the water space materialy, a greater heating
surface, better combustion, & a freer circulation of the water in the boiler is thus
obtained.
(Fig. 3) shows an enlarged section of improved corrugation to be used in the
manufacture of the furnaces, combustion chambers, tubes, and the like, but, plain
plates, and tubes can be applied without departing from the invention.
To further describe my invention, reference is had to (Figs. 4, & 5,) the com-
bustion chambers, & saddle plates being returned over the crowns of the furnaces,
to allow the diagonal water tubes to be fitted between the saddle plates, and the
combustion chamber crowns, in the same manner as described above.
The longitudinal fire tubes being dispensed with, I, therefore apply water tube
boxes, fitted between the combustion chambers, and the front end of the boiler,
with vertical water tubes fitted therein.
(Fig. 6) shows one method of applying the water tubes in the tube boxes.
I may mention that cylindrical, or oval water tube boxes, and larger or smaller
straight or bent tubes can be fitted as desired, without departing from the inven-
tion, altho' this is not shown in the accompanying drawings.
In the event of round, or oval water tube boxes being used, vacant spaces would
be left at the sides, and corners of the combustion chambers, those spaces I.
provide in my invention to be filled in with longitudinal fire tubes making a
combination of water tube, & multitublar boiler, thus utilising all available space
for the purpose of generating steam.
In this method of applying my invention, as shown in (Figs. 4, & 5,) a gain
of more than double the heating surface, better combustion, larger steam space.
and a more rapid circulation of water throughout the boiler will thus be obtained,

page_text: the weight of water to be used in the boiler being reduced by tons, steam can
therefore be raised in less than half the time usually taken by the cylindrical
multitublar boilers now in use.
This invention does not only apply to boilers having three furnaces, as shown in
the accompanying drawings, but is applicable to boilers having a greater or
lesser number of furnaces and combustion chambers.
בד
1
improvements in Cylindrical Marine Boilers.
I, FRANCIS DRAKE, of 157, Fenchurch Street, London, E.C., Marine 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:-
My invention relates to cylindrical marine boilers. but more especially to that
class of cylindrical boiler employed on steam vessels and my object is to provide
a boiler which will possess greater strength in the internal parts, greater heating
surface, better combustion, increased water circulation, and at the same time
reduce the quantity of water used in the said boiler as against the ordinary multi-
tubular boilers at present in use.
Referring to the accompanying drawings which illustrate so much of a cylin-
drical marine boiler constructed in accordance with my said invention as is needful
in order that the same may be clearly understood.
Fig. 1, represents a part front elevation and part vertical section of my improved
boiler.
Fig. 2, is a longitudinal vertical section on line x, x Fig. 1.
Fig 2, an enlarged view of an improved form of corrugation used in various
parts hereinafter referred to.
Fig. 3, represents a part front elevation and part vertical section of a modified
form of my improved boiler and
Fig. 4, a vertical longitudinal section on line y y Fig. 3.
Like letters of reference indicate corresponding parts in the several figures.
Referring first to Figures 1 and 2, A represents the generator or boiler as a
whole, and B, B, B the furnaces thereof. C the combustion chambers, and D the
saddle plates.
In carrying my invention into practice the saddle plates D) and combustion
chambers C are returned over the crowns of the furnaces B for a sufficient distance
to allow of one or more diagonal tubes E being fitted between the saddle plates
and crown of the combustion chambers, said crowns being rounded off as shown,
by this arrangement the longitudinal fire-tubes F are shortened between the walls
of the combustion chambers and the front end plate F¹ of the boiler. Although
this method of construction does not contract the water space materially, a greater
heating surface, better combustion, and a freer circulation of the water in the
boiler is obtained.
Fig. 2 illustrates on full sized scale the improved form of construction of
corrugation preferably used in the walls of the furnaces combustion chambers,
tubes and the like, but plain plates and tubes may be used without departing from
the nature of my invention.
Taking 1, 1 as centre line of plate, the undulations alternate on either side of
said centre line.

page_text: Distance centre to centre of undulation 3 inches.
Radius (outer) of crown 14 inches.
Radius of connecting curves 1 inch.
Thickness of plate
inch.
Referring now to the form of construction iustrated in Figs. 3 and 4. the com-
bustion chambers and saddle plates are returned over the crowns of the furnaces
to meet the front end plates of the boiler the diagonal water tubes being fitted
between the saddle plates and the crowns of the combustion chambers as herein-
before described.
In this form of construction, I dispense with the longitudinal fire tubes, and in
place thereof I use water tube chambers G arranged between the combustion
chambers C and the front end plate F¹ of the boiler. provided with vertical water
tubes G fitted therein.
In the present instance the water tube chambers are square, but round or
oval chambers may be used and the tubes varied in size and shape, (for instance
bent in S shape or corrugated) the chambers being stayed externally or internally
it desired.
The tube G may also be arranged in other ways than vertical, for instance on
the cross.
In the event of round, or oval water tube chambers being used, vacant spaces
would be left at the sides and corners of the combustion chambers, these spaces,
I may if desired, fill in with longitudinal fire tubes, thus making a combination of
a water tube and multitubular boiler and utilising all these available spaces for
the purpose of generating steam by increasing the heating surface.
It has been found in practice that the front row of the water-tubes G are
seriously affected by the intense heat, and to obviate this, I place in front of the
hereinbefore mentioned water tubes G the diagonal water tubes E, said tubes E
distributing the flames before entering the water chamber G¹, besides giving
greater staying power to the crown of the combustion chamber and causing
increased water circulation at the back of the boiler.
In this form of construction a gain of more than double the heating surface,
better combustion, greater steam space and a more rapid circulation of the water
throughout the boiler is obtained.
The quantity of water in the boiler being reduced by tons, steam, can therefore
be raised in half the time usually occupied by the cylindrical multitubular boilers
in use at the present time.
It is not necessary to keep the lower and upper plates of the combustion
chambers on a level as they may be raised at the front end of the boiler, more-
over the bottom corner of said chambers may be rounded off the same as at the
top, and I may if desired support the saddle plate from the crown of the furnace.
The inner walls of the two side combustion and the water tube chambers, may
be connected by stay-tubes to the side walls of the centre combustion chamber
and water-tube chamber thus giving increased heating surface.
I may further extend the tubes G as in Figs. 3 and 4 beyond the saddle plate
on either side and back of the combustion chamber as at G* connecting the
crown with the bottom plate of said combustion chamber, thereby causing the
circulating water to arrive from the bottom of the boiler.
The advantages of these forms of boilers are (1) Combustion is more effectually
completed (2) A considerable saving in fuel (3) The escaping gases are of a
much lower temperature (4) Heating surface is increased, creating a greater
circulation of the water, thereby preventing incrustation, and loosening all
scale (5) Less tendency to produce smoke and lower funnel temperature
(6) Expansion and constraction between the furnaces combustion chambers, and
tube plates more in unison. (7) A still further advantage is obtained by using one
boiler of a larger size to replace two smaller boilers, thus gaining more space in
the ships capacity for cargo or for coal bunkers.

page_text: My invention is not only applicable to boilers having three furnaces, as shown
in the accompanying drawings, but also to boilers having a greater or less number
of furnaces and combustion chambers, double or single ended boilers.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
(1) A cylindrical marine boiler characterized by the employment of corrugated
furnaces, combustion chambers, tubes and the like, shortened longitudinal fire
tubes, the return of the saddle plate over the crown of the furnace to allow of
fitting the diagonal water tubes on same all substantially as described
illustrated with reference to Fig. 1 and 2, of the accompanying drawings.
and
(2) A multitubular cylindrical marine boiler substantially as described with
reference to Figs. 3 and 4 of the accompanying drawings.
(3) In cylindrical marine boilers the use of corrugated furnaces, combustion
chambers, tubes and the like constructed substantially as illustrated and described
with reference to Fig. 2 of the accompanying drawings.
(4) Cylindrical marine boilers characterized by the combination of a water tube
and multitubular boiler substantially as described.
Dated this 30th day of July 1900.
LAWRENCE HARDIE DRAKE,
For Francis Drake.