IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS OR GENERATORS FOR STATIONARY OR MARINE PURPOSES.
Year: 1877

page_text: "
LETTERS PATENT to William Henry Mirfin, of the City of Manchester,
Engineer, for the invention of IMPROVEMENTS IN THE CONSTRUCTION OF
STEAM BOILERS OR GENERATORS FOR STATIONARY OR MARINE PURPOSES.
Sealed the 18th December 1877, and dated the 21st June 1877.
PROVISIONAL SPECIFICATION left by the said William Henry Mirfin at
the Office of the Commissioners of Patents on the 21st June 1877.
WILLIAM HENRY MIRFIN, of the City of Manchester, Engineer. "IMPROVEMENTS
IN THE CONSTRUCTION OF STEAM BOILERS OR GENERATORS FOR STATIONARY OR
MARINE PURPOSES,"
The object of this invention is to construct steam boilers or generators for
stationary or marine purposes of great strength, large heating surface, and which
shall be readily accessible for examination, cleaning, and repairs.
Une section of this my improved construction of steam boiler or generator
consists of an horizontal main cylinder, having two or more cylinders placed in
longitudinal contact with each other, and upon the same level at a suitable dis-
tance above and parallel with the main cylinder, each of such upper cylinders
being connected to the main cylinder by one or more rows of conical or parallel
tubes or pipes placed in a vertical or in an inclined position.
When conical connecting tubes are used I attach their smaller ends to the upper
part of the main cylinder, and their larger ends to the under part of the upper
cylinders, which I purpose shall be of sufficient diameter to admit a person inside
them, and thus be readily accessible for examination, repairs, or any other purpose.
For stationary purposes the water level in this boiler is situated at or about
the centre of the said upper cylinders, the remaining space thus constituting
the steam space.
The furnace is placed beneath the main cylinder herein-before mentioned, and
the flues, by preference, are so arranged that the flames and products of com-
bustion shall pass along its under surface to the back, and return along its upper
surface, passing meanwhile between the lower part of the connecting tubes or

page_text: pipes to the front, and then travel along the under surface of the upper cylinder,
passing meanwhile between the higher part of the same connecting tubes or
pipes to the back of the boiler, and thence to the chimney; or in some cases I
dispense with the middle flue. I connect the feed water and blow-off pipe or pipes
to the fore end of the main cylinder, which cylinder is also fitted with a man-
hole for obtaining access to the inside.
In some cases I place one or more steam receivers above the upper horizontal
cylinders, and in communication with them, situated, by preference, transversely
with the body of the boiler, but longitudinally if more convenient, and when
more than one steam receiver is used 1 connect them together.
By another arrangement I sometimes attach conical or parallel tubes or pipes
to the under part of the main cylinder, and connect their lower ends to a tube or
mud collector placed longitudinally below the level of the grate bars, and there-
fore not exposed to the action of the fire, and when conical connecting tubes are
used I connect their smaller ends to the said tube or mud collector, and I some-
times introduce the feed water through the said tube or mud collector, which is
also provided with means for blowing out or removing the deposit or sediment.
For stationary purposes one of the sections herein-before described being set
in brickwork constitutes a boiler of itself, but in case greater boiler power is
required a number of such sections are arranged and combined together in one
furnace, according to the power required.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Henry Mirfin in the Great Seal Patent Office on the
20th December 1877.
WILLIAM HENRY MIRFIN, of the City of Manchester, Engineer. "IMPROVEMENTS
IN THE CONSTRUCTION OF STEAM BOILERS OR GENERATORS FOR STATIONARY OR
MARINE PURPOSES."
The object of this invention is to construct steam boilers or generators for
stationary or marine purposes of great strength, large heating surface, and which
shall be readily accessible for examination, cleaning, and repairs.
One section of this my improved construction of steam boiler or generator
consists of an horizontal main cylinder, having two or more cylinders placed in
longitudinal contact with each other, and upon the same level at a suitable dis-
tance above and parallel with the main cylinder, each of such upper cylinders
being connected to the main cylinder by one or more rows of conical or parallel
tubes or pipes placed in a vertical or in an inclined position.
When conical connecting tubes are used I attach their smaller ends to the upper
part of the main cylinder, and their larger ends to the under part of the upper
cylinders, which I purpose shall be of sufficient diameter to admit a person inside
them, and thus be readily accessible for examination, repairs, or any other purpose.
The furnace is placed beneath the main cylinder herein-before mentioned, and
the flues, by preference, are so arranged that the flames and products of con-
bustion shall pass along its under surface to the back, and return along its upper
surface, passing meanwhile between the lower part of the connecting tubes or
pipes to the front, and then travel along the under surface of the upper cylinders,

page_text: passing meanwhile between the higher part of the same connecting tubes or
pipes to the back of the boiler, and thence to the chimney; or in some cases I
dispense with the middle flue. I connect the feed water and blow-off pipe or pipes
to the fore end of the main cylinder, which cylinder is also fitted with a man-
hole for obtaining access to the inside.
In some cases I place one or more steam receivers above the upper horizontal
cylinders, and in communication with them, situated, by preference, transversely
with the body of the boiler, but longitudinally if more convenient, and when
more than one steam receiver is used I them together.
By another arrangement I sometimes attach conical or parallel iubes or pipes
to the under part of the main cylinder, and connect their lower ends to a fube or
mud collector placed longitudinally below the level of the grate bars, and there-
fore not exposed to the action of the fire, and when conical connecting tubes are
used I connect their smaller ends to the said tube or mud collector, and I some-
times introduce the feed water through the said tube or mud collector, which is
also provided with means for blowing out or removing the deposit or sediment.
And in order that this my said Invention may be the more readily seen and
understood, I have hereunto annexed a Sheet of Drawings, illustrating severa!
modifications of my improvements in steam boilers or generators. similar letters
marked upon the several views being used to indicate similar parts.
Fig. 1 is a longitudinal view partly in section, and Fig. 2 is a transverse see-
tion of a generator constructed in accordance with my Invention Fig. 3 is a sec-
tional plan of Fig. 2, across the line a—; Fig. 4 illustrates a modification of
Fig. 2.
Figs. 5, 6, and 7 represent similar views respectively of the same generator,
but with the addition of a mud collector applied thereto, and also showing
the flues and connecting tubes differently arranged.
Figs. S, 9, 10, 11, 12, and 13 are transverse sections of modifications of my
improved construction of steam generators.
In all the views A is the main cylinder, and B. B, the upper cylinders, which in
all cases are arranged upon the same level, and as near as practicable to each other,
and parallel with the main cylinder. The said upper cylinders are of sufficient
diameter to admit a person inside them, and are connected to the main cylinder A
by conical or parallel tubes or pipes (but conical by preference), which are
arranged either vertically as indicated by the letters or in an inclined direc-
tion, as shewn by the letters D, and when conical tubes are used their smaller
ends are connected to the upper part of the main cylinder A, and their larger
ends to the under part of the upper cylinders B, B, as illustrated. E is the fur-
nace, which in all cases is placed underneath and outside the main cylinder A,
and the intervening space between the main and upper cylinders constitutes
one or more flues, and in the latter case being divided by either horizontal or
vertical partition walls, arches, slabs, or plates.
In Figs. 1, 2, 3, and 4 the main cylinder A rests for part of its length upon a
longitudinal midfeather E, and in this case the products of combustion pass along
each side of the said midfeather towards the back end of the generator, where they
rise through suitable openings at each side of the main cylinder, and then enter
the intermediate flue F: they then pass along it in contact with the upper surface
of the main cylinder and the lower ends of the conical tubes on their way towards
the front of the generator, where they once more rise and follow the direction of the
arrows in contact with the under surface of the upper cylinders and the higher
ends of the same connecting tubes until they finally escape into the chimney.
In Fig. 4 is illustrated the same generator with the intermediate space
divided into two flues by a vertical division Fl
In the modifications represented by Figs. 5, 6, & 7 the boiler only differs in
construction from the one illustrated in Figs. 1, 2, 3, and 4 in the main cylinder
being connected to the upper cylinders by conical tubes, which are not in parallel
rows, but alternate in and out, as scen more clearly in Fig. 7. and in the main
cylinder being connected to a mud collector (and feed water heater) G, which is

page_text: situated below the level of the grate bars, and is connected to such main cylinder
by two parallel rows of conical tubes H. This mud collector rests upon cast-iron
frames or stands I, and is not exposed to the direct action of the fire. In this
modification the flame and products of combustion pass round and in contact
with the back end of the main cylinder before reaching the intermediate flue.
In both the foregoing modifications ready access is obtained to the flues
through the apertures J.
In Fig. S I illustrate a modification, shewing the main and upper cylinders
of about equal diameters, and connected by conical tubes arranged in the
same manner as in Fig. 6, and the mud collector G being connected to the
main cylinder by only one row of conical tubes H.
In Fig. 9 the upper cylinders are shewn of smaller diameter than the main
cylinder, and are connected to the latter by conical tubes having their centres
radiating from centre to centre of the cylinders.
In all the preceding modifications of my improved steam generator I shew the
upper cylinders in communication with a steam receiver placed transversely
above them, but in Fig. 10 I represent three upper cylinders of smaller diameter
than the main cylinder, and each of such upper cylinders communicating with
one common steam receiver 0 arranged longitudinally.
Figs. 11 and 12 illustrate a combination of two sections of my improved steam
generator, each communicating with one common mud collector G. and one
common steam receiver 0, and placed over one common furnace F. the inter-
mediate space between the main and upper cylinders in the case of Fig. 11 being
subdivided into two horizontal flues by the horizontal fire-clay slabs K, which
are supported at their edges as shewn, and may be further supported by suitable
projections secured to the conical tubes, and the same intermediate space in the
case of Fig. 12 is subdivided by a vertical slab or partition wall L, in order that
the flames and products of combustion from the same fire after reaching the
back end of the generator may come through one flue N to the front, and then
return through the other flue P to the chimney, or by leaving out the parti-
tion L may come forward and escape either at the front or sides.
Fig. 13 represents the same generator as in Figs. 11 and 12, but shews a
separate mud collector and furnace for each section. The flues from each furnace
are also distinet, except that the whole flame and products of combustion may
pass into one common upper flue R, or such flue may be again subdivided, as
in the case of the lower flues.
When I employ a mud collector I prefer to cover the space wherein the same
is placed by metal plates M, or in some cases by a thin arch.
It will be readily apparent that one section of my improved steam generator
being set in brickwork constitutes a boiler of itself, but in case greater boiler
power is required two or more of such sections may be connected together in one
furnace, according to the power required, and it is obvious that more than one
furnace would sometimes be advantageous.
In all the modifications the water level is arranged at or about the centre of
the upper cylinders B, B. the remaining space serving as steam room, and com-
municating as illustrated with the steam receivers 0, which may be one or
more in number, or in some cases may be dispensed with altogether.
This invention is equally applicable in the construction of a steam generator for
marine purposes by substituting metal plates or blocks or cellular iron casings
(which casings may sometimes serve as feed water heaters) in place of the ordi-
nary brick walls and other brickwork used in the erection and "setting" of
stationary steam generators, and the said metal plates, blocks, or cellular ion
casings may be protected against the action of the fire by a lining or covering
of fire-bricks or slabs of other fire resisting material or composition affixed thereio
in any convenient manner. For a
marine boiler, however, I use what other-
wise would be the steam receiver, as an additional water space, and I arrange
the working level of the water to be at or about the centre of such receiver

page_text: or receivers, and thus the upper cylinders will be kept constantly full from
the water in the steam receiver or receivers, and I obtain additional steam space
by applying a steam holder situated at a higher level, and in communication
with the said receiver or receivers.
Having thus particularly described and ascertained the nature of this my said
Invention, together with the best methods with which I am acquainted for carry-
ing the same into practical effect, I wish it to be distinctly understood that I do
not confine myself to the precise details, relative proportions, or dimensions
of the various parts of the steam generator herein-before described and illus-
trated on the accompanying Drawing, as the same may be considerably varied
without departing from the Invention, and that I do not claim any of the parts
separately or except as used in combination and with the fire outside and beneath
the main cylinder or cylinders; I further wish it to be understood that I claim,
1st. The combination, arrangement, and mode of constructing the several modi-
fications of steam boilers or generators with the fire beneath the main cylinder or
cylinders, and with or without a mud collector, substantially as and for the
purposes herein-before described and illustrated on the accompanying drawing.
2nd. Using separately or combining together any part or parts of the several
modifications herein-before described and illustrated on the accompanying
Drawing in the construction of a steam boiler or generator.
In witness whereof, I, the said William Henry Mirfin, have hereunto set
my hand and seal, this 19th day of December, in the year of our Lord
One thousand eight hundred and seventy-seven.
WILLIAM HENRY MIRFIN. (L.S.)