IMPROVEMENTS IN STEAM BOILERS
Year: 1875

page_text: LETTERS PATENT to John Henry Mac Ilwaine and Richard Lewis,
both of Abercorn Basin, Belfast, for the Invention of "IMPROVEMENTS
IN STEAM BOILERS."
Scaled the 9th December 1875, and dated the 11th October 1875.
PROVISIONAL SPECIFICATION left by the said John Henry Mac Ilwaine
and Richard Lewis at the Office of the Commissioners of Patents,
with their Petition, on the 11th October 1875.
We, JOHN HENRY MAC ILWAINE and RICHARD LEWIS, both of
Abercorn Basin, Belfast, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM BOILERS," to be as follows:-
This Invention has for its object improvements in steam boilers.
The improvements relate to the flues of Lancashire, or Cornish, or
any other boilers which consist of an outer shell and an inner fluc or
flues.
The improvements consist in dividing the flue or flues into lengths or

page_text: chambers, the first length or chamber extending from the front of the
boiler to any desirable distance behind the bridge, and strengthened by
external expansion rings, and the remainder of the flues into any
number of lengths or chambers, according to the pressure to be used and
other circumstances. Into each end of each length or chamber we
put a disc, flat or dished, of the same diameter as the flue, and connect
same by angle iron rings or flanges formed on discs. Across each length
or chamber we introduce a tube or tubes according to the length of
such chamber, and in such position as best to obstruct the passage of
the heated gases through it. Into any part of these discs we put a hole
of sufficient size but no larger than will allow the flame and heated
gases free vent in their passage from the furnace to the chimney.
The chambers aro placed end to end in the shell of the boiler with the
discs a suitable distance apart, by preference 5 or 6 inches, but this
distance may be increased or decreased, and from disc to disc we fit a
tube, in diameter equal to the before-mentioned hole, put in the discs,
and in length the distance of the discs apart, and connected to discs by
flanges formed on the tubes themselves or by angle iron rings fitted on
them.
The advantages obtained by this Invention are,—
First. The strengthening of the flues by the discs, by reason of which
we are able to make the flues of thinner plates than would otherwise be
necessary and yet have them sufficiently strong for very high pressures.
The thinner plates offering less resistance to the passage of the heat to
the water insure greater economy.
Second. Additional heating surface added to the flues by the intro-
duction of the discs, and as the flames and heated gases must impinge
on them they constitute the best heating surface in a boiler.
Third. A much better admixture of the gases and consequently more
perfect combustion than is possible in an ordinary flue caused by the
obstruction offered by the discs.
Fourth. The constant changing of places of the gases in the centre of
flue which have not come in contact with the surface to be heated with
those at the sides which have partly or wholly given up their heat.
Fifth. Causing a much larger portion of the circumference of the flue

page_text: and a much greater length of the tubes placed in the flue to be heated
by compelling the flame and heated gases to pass lower down than is
the case in any ordinary plain flue.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Mac Ilwaine and Richard Lewis
in the Great Seal Patent Office on the 10th April 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
HENRY MAC ILWAINE and RICHARD LEWIS, both of Abercorn Basin,
Belfast, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of October, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
ninth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said John Henry Mac Ilwaine and
Richard Lewis, Her special license that we, the said John Henry
Mac Ilwaine and Richard Lewis, our executors, administrators, and
assigns, or such others as we, the said John Henry Mac Ilwaine
and Richard Lewis, our executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN STEAM BOILERS," upon
the condition (amongst others) that we, the said John Henry Mac
Ilwaine and Richard Lewis, our executors or administrators, by an
instrument in writing under our or their hands and seals, or under
the band and seal of one of us or them, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.

page_text: The improvements relate to the flues of Lancashire, or Cornish, or
any other boilers, which consist of an outer shell and an inner flue or
flues.
The improvements consist in dividing the flue or flues into lengths or
chambers, the first length or chamber extending from the front of the
boiler to any desirable distance behind the bridge and strengthened by
external expansion rings, and the remainder of the flues into any
number of lengths or chambers, according to the pressure to be used and
other circumstances. Into each end of each length or chamber we put
a disc, flat or dished, of the same diameter as the flue, and connect same
by angle iron rings or flanges formed on discs. Across each length or
chamber we introduce a tube or tubes according to the length of such
chamber, and in such position as best to obstruct the passage of the
heated gases through it. Into any part of these discs we put a hole of
sufficient size, but no larger than will allow the flame and heated gases
free vent in their passage from the furnace to the chimney.
The chambers are placed end to end in the shell of the boiler with the
discs a suitable distance apart, by preference 5 or 6 inches, but this
distance may be increased or decreased, and from disc to disc we fit a
tube in diameter equal to the before-mentioned hole put in the discs and
in length the distance of the discs apart, and connect it to discs by
flanges formed on the tubes themselves or by angle iron rings fitted on
them.
The annexed Drawings show our improvements.
Figures 1, 2, 3, and 4, show a two flued boiler made on our principle;
Figure 1 is a longitudinal section of boiler with one flue shown in

page_text: Figures 5, 6, 7, 5, show our improvements as applied to a one flued
boiler, and correspond to Figures 1, 2, 3, 4, as above..
In Figures 1 to Sa is shell of boiler; b, first chamber or furnace ;
c, strengthening rings; d, chambers of flue; e, discs in ends of
3 chambers; f, cross tubes in chambers; g, connecting tubes.
Figures 9, 10, 11, drawn to a larger scale show means by which we
attach connecting tubes to discs in ends of chambers.
Figures 12, 13, show a sectional elevation and plan in section of an
upright boiler constructed on our principle. a is shell of boiler;
b, furnace; c, chamber; d, cross tubes; e, discs; f, connecting tubes.
The advantages obtained by this Invention arc,-
First. The strengthening of the flues by the discs, by reason of which
we are able to make the flues of thinner plates than would otherwise
be necessary, and yet have them sufficiently strong for very high
pressures. The thinner plates offering less resistance to the passage of
the heat to the water insure greater economy.
Second. Additional heating surface added to the flues by the intro-
duction of the discs, and as the flames and heated gases must impinge
on them they constitute the best heating surface in a boiler.
Third. A much better admixture of the gases and consequently more
perfect combustion than is possible in an ordinary flue caused by the
obstruction offered by the discs.
Fourth. The constant changing of places of the gases in the centre of
5 flue which have not come in contact with the surface to be heated with
those at the sides which have partly or wholly given up their heat.
Fifth. Causing a much larger portion of the circumference of the flue
and a much greater length of the tubes placed in the fluc to be heated
by compelling the flame and heated gases to pass lower down than is
the case in any ordinary plain flue.
Sixth. Making a perfectly elastic flue for expansion and contraction

page_text: What we claim is the construction of steam boilers substantially as
described.
In witness whereof, we, the said John Henry Mac Ilwaine and
Richard Lewis, have hereunto set our hands and seals, this
Twenty-third day of March, in the year of our Lord One thou-
sand eight hundred and seventy-six.
JOHN H. MAC ILWAINE. (L.S.)
RICH. LEWIS.
(L.S.)