IMPROVEMENTS IN OR APPLICABLE TO BOILERS FOR GENERATING STEAM."
Year: 1880

page_text: LETTERS PATENT to William Henry Mirfin, of the City of Manchester, in the
County of Lancaster, Engineer, and Emanuel Nield, of Oldham, in the said
County, Manager, for an Invention of "IMPROVEMENTS IN OR APPLICABLE
TO BOILERS FOR GENERATING STEAM."
PROVISIONAL SPECIFICATION left by the said William Henry Mirfin and
Emanuel Nield at the Office of the Commissioners of Patents on the 4th
December 1880.
WILLIAM HENRY MIRFIN, of the City of Manchester, in the County of Lancaster,
Engineer, and EMANUEL NIELD, of. Oldham, in the said County, Manager.
"IMPROVEMENTS IN OR APPLICABLE TO BOILERS FOR GENERATING STEAM."
Our Invention refers to boilers having internal flues, and consists in improved
combinations of the same, whereby a better combustion of the gases and a greater
heating surface is obtained, and which heating surfaces are so disposed and
arranged as to divide, divert, and break up the currents of heated gases and so
compel them to pass in contact with, and give up their heat more fully to, the
surfaces to be acted upon. One of our improved combinations consists of a
cylindrical shell, having one or two flues extending from end to end of the shell
these flues we prefer to make of cylinders connected by flanges on the exterior of
the cylinders and rivetted together; but instead of making the flue or flues as in
the ordinary mode of construction we omit one or more cylinders forming the
ordinary flue or flues, and substitute in place of them a section formed of a series
of flue tubes, one of which is sufficiently large to allow a man to pass through to
clean or repair the tubes or flues.
The interposed sections of tubes are formed by two end or tube plates, which
are secured to exterior flanges on the cylindrical portions of the main flue, and
the tubes have exterior flanges by which they are secured to the tube plates; or
the tube plates are bent out and formed to an angle to receive the ends of the large
tube, or both tube plates and main flue are enlarged to form a lap joint, the smaller
tubes being secured in the ordinary manner of securing tubes in multitubular
boilers.
We prefer that the large tube should be in the centre and surrounded by smaller
tubes.

page_text: In some places we place conical or other water tubes or "water pockets" across
parts of the main flue or flues.
Another combination and arrangement, according to our Invention, refers to the
flues of boilers formed of a series of cylinders of small and large diameter, in which
the ends of the small cylinders are enlarged to make an overlapping joint with the
large cylinders, and this modification of our Invention consists in forming the
smaller cylinders of the flue or flues, or some of them, with corrugations, the wave
of the corrugation passing longitudinally so that cross sections of the cylinder are
circles, but of varying diameters. The large cylinders of the flue or flues are plain,
and in and across them we form or place conical or other water tubes, which
increase the circulation of the water and strengthen the large cylinders of the flue
or flues, and we sometimes provide the said large cylinders with "water pockets"
projecting inwardly from the shell of the cylinders.
Another combination and arrangement, according to our Invention, relates to
and consists of boilers having two furnace flues, which form a junction with an
oblong or oval chamber, which again branches into two flues, and again forms a
junction with an oblong or oval chamber, and again branches into two flues, and
so on, as often as desired.
By our Invention we connect the oblong chambers by means of corrugated
cylinders, which are secured to saddle plates in the chambers or to the end plates
of the chambers, or to flanges on the ends of the chambers, and we place conical or
other water tubes in a vertical or inclined position in the said chambers, and we
sometimes combine "water pockets" therewith.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Henry Mirfin and Emanuel Nield in the Great Seal Patent
Office on the 1st June 1881.
WILLIAM HENRY MIRFIN, of the City of Manchester, in the County of Lancaster,
Engineer, and EMANUEL NIELD, of Oldham, in the said County, Manager.
"IMPROVEMENTS IN OR APPLICABLE TO BOILERS FOR GENERATING STEAM."
Our Invention refers to boilers having internal flues, and consists in improved
combinations of the same, whereby a better combustion of the gases and a greater
heating surface is obtained, and which heating surfaces are so disposed and arranged
as to divide, divert, and break up the currents of heated gases, and so compel them
to pass in contact with, and give up their heat more fully to, the surfaces to be acted
upon.
One of our improved combinations consists of a cylindrical shell having one or
two flues extending from end to end of the shell; these flues we prefer to make of
cylinders connected by flanges on the exterior of the cylinders and rivetted
together, but instead of making the flue or flues as in the ordinary mode of
construction we omit one or more cylinders forming the ordinary flue or flues, and
substitute in place of them a section formed of a series of flue tubes, one of which
is sufficiently large to allow a man to pass through to clean or repair the tubes or
flues.
The interposed sections of tubes are formed by two end or tube plates which are
secured to exterior flanges formed on the cylindrical portions of the main flue, and
the tubes have exterior flanges, by which they are secured to the tube plates, or.
the tube plates are bent out and formed to an angle to receive the ends of the large
tube, or both tube plates and main flue are enlarged to form a lap joint, the smaller
tubes being attached by flanges to the tube plates or secured in the ordinary
manner of securing tubes in multitubular boilers.
In some cases we place conical or other "water tubes" or
across parts of the main flue or flues.
"water pockets"
Another combination and arrangement according to our Invention relates to and
consists of boilers having two furnace flues which form a junction with an oblong
or oval chamber which branches into two or more flues or tubes, and again forms a
junction with an oblong or oval chamber, and again branches into two or more.
flues or tubes, and so on, as often as desired.
By our Invention we connect the oblong chambers by means of corrugated
cylinders, which are secured to saddle plates in the ends of the chambers or to
tube plates at the ends of the chambers, or to flanges on the ends of the chambers,
and we place conical or other water tubes in a vertical or inclined position in the
said chambers, and we sometimes combine "water pockets" therewith. Fig. 1
shows a plan view of a boiler according to one modification of our Invention with
the shell (a) of the boiler in section, and an outside view of the furnaces and flue
tubes; and Fig. 2 shows a similar view of a different arrangement of the sections.
forming the flue tubes, but omitting to show those portions of the tubes forming
the furnace part of the boiler.
Fig. 3 shows a view similar to that shown by Fig. 2 of a modification of boiler
according to our Invention, but with "water pockets" formed in the cylindrical
lengths of the flues in place of water tubes shown in Figs. 1 and 2.
It will be seen from Figs. 1, 2, and 3 that by our Invention the flue tubes are
made up of sections formed of single tubes (6) with sections formed of a series of
small tubes d and d', and that in arranging these sections one, two, or more plain.
cylindrical sections (b) are or may be connected together alternately with sections
formed by a series of small tubes d and d',
i

page_text: The sections formed by a single plain cylinder (b) in the main flues have each
one or more conical or cylindrical water tubes 6' secured across them in either a
vertical or diagonal position, or they may have "water pockets" (6²) (see Fig. 3)
formed in them or "water pockets" (62) combined with water tubes (6').
Figs. 4, 5, 6, and 7 are each cross sections of this modification of our improved
boilers, showing the arrangement of those sections of the flue tubes formed of a
series of small tubes (d and d¹).
Fig. 4 illustrates our improved flue as applied to single flued boilers, and Figs. 5,
6, and 7 our improved flues as applied to double flued boilers, a being the shell of
the boiler in each case.
Figs. 8, 9, and 10 are enlarged views of portions of our improved flues detached
to show the mode of connecting the plain sections 6 with the tube sections formed
of a series of tubes d and d³ of our improved flue tubes.
Fig. 8 illustrates the mode of connecting together the sections of the flue when
the series of smaller tubes & and d' are arranged as illustrated by Figs. 4 and 5.
Fig. 9 illustrates the mode of connection when the sections of smaller tubes
(d and d) are arranged as shown in Fig. 6, and Fig. 10 the mode of connection
when the series of tubes (d and d³) are formed, secured, and arranged as illustrated
by Fig. 7.
It will be seen that in all arrangements of those sections of the flues formed by
a series of smaller tubes (d and d¹) there is one tube (d) sufficient in size to allow
a man to pass through, which enables every part of the flues from end to end to be
inspected and repaired when required from the inside of the flue.
Both ends of each series of smaller tubes d'and d are secured to or in a tube
plate d².
In the illustrations shown by Figs. 4, 5, and 6, and by Figs. 8 and 9, each end of
the smaller tubes d¹ and the "man tube d, Figs. 4, 5, and 8, is flanged outwards,
as shown, and that portion of the flange of each tube d and d² which comes to the
outer edge of the flue is formed and arranged to be secured by the same rivets as
are used for connecting the tube plate d² and the flange of the large cylinder or
tube (b) of the flue, as shown. To give longitudinal elasticity to the flues and
so make the joints as not to be liable to leak, and in such manner as to be easily
made tight by caulking from the inside of the flue when required, we flange the
large cylinders (b) outwards and place a caulking ring (d³) between the tube
plate (d2) and the flange of the large tube (b) of the flue with which it is united.
In the arrangements illustrated by Figs. 6, 7, and 9 the tube plates are formed with
a cylindrical projection for the central "man tube" (d) to be secured by rivets,
as shown.
In the arrangement shown by Fig. 7 the tube plates d² are bent and formed so
as to be united with the enlarged portion (6) of the ends of the main flue, as shown
in Fig. 10.
The smaller tubes d', shown in Figs. 7 and 10, are secured in the tube plates (²)
by any of the ordinary methods of securing tubes in the tube plates of boilers, but
they may have external flanges formed upon each end and be secured to the tube
plate d by rivets.
We have shown the tubes of both sections formed of a series of smaller tubes d
and das cylinders, which form we prefer, but do not limit ourselves to it, as the
tubes may be oval or of any other desired form, and the "man tube" may be
made oval in cross section, and if this tube in each section is large enough for a
man to pass through the other tubes d' may be of any convenient number, or
diameter, or arrangement.
The furnace parts of the flues are shown in Fig. 1 as formed of plain cylinders 6*,
with flanged seams,
but we do not limit ourselves to such plain cylinders, as we
can also form the furnace part of the flues of corrugated cylinders or any other
suitable form of tubes.
Fig. 11 is a plan view showing the shell (a) in section of a boiler according to
another modification of our Invention; Fig. 12 is a plan shewing corrugated

page_text: furnaces combined with an oblong mixing chamber, and Figs. 12ª, 12b, and 12°,
show mixing chambers with different arrangements of water tubes and pockets.
Fig. 13 is a partial plan section on an enlarged scale showing one mode of
connecting the corrugated flues with the oblong chambers.
Figs. 14 to 21, inclusive, are vertical cross sections, showing various forms of
oblong combustion or mixing chambers, which are connected by corrugated flues
according to our Invention.
In Fig. 14 water tubes are shown, and in Fig. 16 water tubes combined with
water pockets; in Figs. 15, 17, 18, 19, 20, and 21 the tubes and water pockets are
not shown.
In Fig. 15 the section is supposed to be through the flues just in front of the end
plate of the chamber.
Fig. 22 is a section illustrating a method of forming corrugated flues; and Figs. 23,
24, and 25 are outside views of such flues, each Figure showing a different mode of
forming the connection with the oblong chamber.
In Fig. 11 the furnace flues are shown formed of plain cylinders 6*, connected
together by what are known as " bowling" hoops (63). But the furnace part of the
tubes may be made entirely of plain cylinders with flanged seams, or are or may
be formed entirely of cylinders (64) corrugated as illustrated by Fig. 12.
In Fig. 11 each combustion or mixing chamber e is shown with three conical or
other water tubes e¹, but any convenient number of tubes arranged in any convenient
manner may be used with or without "water pockets" e³, as illustrated by
Figs. 12, 12, 12b, and 12º.
In Figs. 11 and 12 the outside parts of the ends of the corrugated flue tubes f
are rivetted to the circular sides of the oblong chamber e, and the inner parts to a
flanged saddle plate e³.
In Fig. 13 the entire end of the corrugated flue or tube f is shown rivetted to a
plate e forming the end plate of the chamber e, which is bent to join with the plates
forming the sides of the oblong chambers e as shown.
The plates forming the corrugated cylinders f may have the corrugations formed
before or after the plates are made into cylinders, or the cylinders may be constructed
of rings made and formed similarly to what are known as "bowling" hoops, and
combined or connected with plain rings of plate to form the lengths required, as
illustrated by Figs. 22 to 24, inclusive, and such rings may either be rivetted or
welded together to make up the entire length of corrugated cylinder required, and
such cylinders are secured to the oblong chambers as herein before described and
illustrated by Figs. 22 to 24, inclusive.
We have now particularly described the nature of our Invention and the modes
of carrying it into effect, and we may here state that we are aware that flues have
been proposed where one large flue has branched into a series of small flue tubes,
and that "water tubes" and "water pockets" across flues are well known, and that
flues combined with oblong combustion chambers having "water tubes" in them
have been proposed, and that corrugated cylinders and flues are old, and therefore
we make no claim to these parts in themselves, but what we do claim as new and
our Invention is,―
Firstly. The combination, as hereinbefore described and illustrated by the
Drawings, of a flue or flues formed by a cylinder or cylinders (b) of large diameter
with a series of tubes (d and d) of smaller diameter (one of them being large
enough for a man to pass through), the sections formed by the cylinders b and the
tubes d and d being united as hereinbefore described, and more particularly
illustrated by Figs. 8, 9, and 10 of the Drawings.
Secondly. The combination of large flue cylinders (b) with a series of smaller
tubes d and d', the cylinders 6 having "water tubes" or "pockets" 6' and b²,
substantially as herein before described and illustrated by Figs. 1 to 10, inclusive,
of the Drawings.
Thirdly. The combination of combustion or mixing chambers (e) having "water
tubes" (e¹) or "pockets" (e²), connected to and combined with corrugated tubes or

page_text: cylinders (f), substantially as hereinbefore described and illustrated by Figs. 11
to 24, inclusive, of the Drawings.
Fourthly. The combination of furnace tubes formed of plain cylinders (b*), having
flanged seams, or made of plain cylinders (b*) and "bowling" hoops, or formed of
corrugated cylinders (6) only, with flues constructed and combined together as
.hereinbefore described and illustrated by the Drawings.
In witness whereof, we, the said William Henry Mirfin and Emanuel Nield,
have hereunto set our hands and seals, this Thirty first day of May, in the
year of our Lord One thousand eight hundred and eighty one.