IMPROVEMENTS IN STEAM BOILERS
Year: 1854

page_text: LETTERS PATENT to John Mac Farlane, of Renfrew, in the County of
Renfrew, North Britain, Manager, for the Invention of "IMPROVEMENTS
IN STEAM BOILERS."
Scaled the 22nd August 1854, and dated the 31st May 1854.
PROVISIONAL SPECIFICATION left by the said John Mac Farlane at
the Office of the Commissioners of Patents, with his Petition, on the
31st May 1854.
I, JOHN MAC FARLANE, of Renfrew, in the County of Renfrew, North
Britain, Manager, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM BOILERS" to be as follows:-
This Invention relates to various arrangements of steam boilers of the ver-
tical tubular kind, and capable of use for all the ordinary purposes to which
steam boilers are applied. Under the marine form, the tubes ranged in rows
in the usual way are disposed vertically through the main flue, and being
open at each end they form communications between the upper and lower
layers of water in the boiler, the water being made to circulate through the
tubes, whilst the furnace heat plays upon the outsides of the tubes. Instead of
being plain cylinders, the tubes are made of what may be termed a differential
transverse section, that is to say, they are of the egg-oval or other similar

page_text: form, in transverse section, whilst at the same time the calibre tapers, or is
narrowed from end to end. The small end is downwards, so that the generated
steam, in passing off upwards from the interior, has greater facility of escape
clear of the water than in common tubes. The tubes are set with the narrow
side of the oval next to the flame, so that the flame may envelope the greater
part of the tube. In plan the tubes are not set in rows behind one another,
but the second row fills up the interstices of the first row, which splits the
draught and makes it go round the thick side or back side of the oval tube,
thus making the entire tube available for the generation of steam. The tubes
or sectional spaces may be of various transverse sections, so as to carry out
the herein-before described views, and they may also bo variously arranged
as regards their position in the boiler.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Mac Farlane in the Great Seal Patent Office on the 25th
November 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MAC FARLANE, of Renfrew, in the County of Renfrew, North Britain, Manager,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of May, in the year of our Lord
One thousand eight hundred and fifty-four, in the seventeenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Mac Farlane, Her special license that I, the said John
Mac Farlane, my executors, administrators, and assigns, or such others as I,
tho said John Mac Farlane, my executors, administrators, or 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 "IMPROVE-
MENTS IN STEAM BOITES," upon the condition (amongst others) that I, the
said John Mac Farlane, by an instrument in writing under my hand and seal,
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
immediately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said John Mac Farlane, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment, reference being had to the accompanying Drawings, and to the letters
and figures marked thereon, that is to say :-
My said Invention relates to various arrangements of steam boilers of the
vertical tubular kind, and capable of use for all the ordinary purposes to which
steam boilers are applied. Under the marine form, the tubes ranged in rows
in the usual way are disposed vertically through the main flue, and being open
at each end they form communications between the upper and lower layers of
water in the boiler, the water being made to circulate through the tubes whilst
the furnace heat plays upon the outsides of the tubes. Instead of being plain
cylinders, the tubes are made of what may be termed a differential transverso
section, that is to say, they are of the egg-oval or other similar form, in trans-
verse section, whilst at the same time the calibre tapers, or is narrowed from
end to end. The small end is downwards, so that the generated steam in
passing off upwards from the interior has greater facility of escape clear of the
water than in common tubes. The tubes are set with the narrow side of the
oval next to the flame so that the flame may envelope the greater part of
the tube. In plan the tubes are not set in rows behind one another, but the
second row fills up the interstices of the first row, which splits the draught and
makes it go round the thick side or back of the oval tube, thus making
the entire tube available for the generation of steam. The tubes or sectional
spaces may be of various transverse section, so as to carry out the herein-
before described views, or some of them. As an example, plain conical or taper
tubes may be adopted, that is to say, the tubes may be circular in transverse
section, the taper or differential formation being merely in the direction of
the tubes length. The tubes may also be variously arranged as regards their
position in the boiler.
And in order that my said Invention may be properly understood, I shall
now proceed to describe the several explanatory Figures on the two Sheets of
Drawings hereunto attached. Each Sheet of the said Drawings illustrates a
separate modification of my improved arrangement of steam boiler as adapted
for marine purposes.
On Sheet 1 of the Drawings, Figure 1 is a front elevation of one form of
marine steam boiler, as constructed according to my improvements, one half
being in section through the tubes; Figure 2 is a vertical section taken
through one of the furnaces and through the main flue; Figure 3 is a hori-
zontal section, one half being taken just above the fire bars and the other half

page_text: .
through the tubes; and Figure 4 is a plan, as far as regards the upper half,
the lower half being a horizontal section taken above the upper tubo plate..
On Sheet 2 of the Drawings, Figure 1 is a front clevation of a marine steami
boiler, one half being in section through the tubes; Figure 2 is a vertical
section taken through one of the furnaces and through the main flue; Figure
3 is a horizontal section, one half being taken just above the fire bars and the
other half above the upper tube plate; and Figure 4 is a plan, as far as regards
the upper half, the lower half being a horizontal section through the tubes.
In the modification of boiler, represented on Sheet 1 of the Drawings, there
are two furnaces A near the bottom of the boiler, and these furnaces extend
from front to back, and are surrounded by water spaces in the usual manner.
The flames and heated gases pass off at B, at the back of the furnaces, and
enter the vertical tube chamber C, above the furnaces, this chamber C being
separated from the furnaces by the horizontal water space D passing through
this chamber C from back to front; the flames and gases next enter the main
up-cast flue E by lateral or side openings F, and pass off at G up the chimney.
The tube chamber C is traversed by a series of vertical tubes II, of peculiar
form, set in rows across the boiler, the tubes of each row being opposite tho
interstices of the adjacent rows. These tubes are tapered in calibre from end
to end, the smaller ends being downwards, and they are fixed in top and bottom
tube plates in the usual way. In transverse section they present a contour
resembling an egg-oval, the narrow side I being towards the advancing line of
the flames, so that the flames envelope cach tube very completely in passing;
this action being assisted by the position of the tubes immediately behind,
which causes the currents of flames to be split and bent laterally so as to act
to some extent on the enlarged back J of the tube in each case.
In the modification represented on Sheet 2 of the Drawings, very nearly
the same general arrangement as that represented on Sheet 1 is adopted.
Here the two furnaces A discharge their products of combustion into the back
passage B, leading into the tubo chamber C, which is bounded at top and
bottom by the horizontal water spaces D. In this way the gaseous current
reaches the front of the boiler, when it gains the throat E of the up-take flue
leading off to the chimney at G. The tubes H are tapered from end to
end in the same way as those in the former modification, the smaller ends
being downwards; they are also arranged in transverse rows, the tubes of each
row being opposite the interstices in the adjact rows. In transverse section,
however, they are of circular contour, tubes of this form being of casier con-
struction than those represented in the first modification.
that tubes of various other transverse sections may be adopted, such tubes
It is also obvious,

page_text: being in all cases tapered either uniformly or diffirentially, and being arranged
with their narrow ends downwards. And it is obvious that the same descrip-
tions of water space tubes may be adopted for land and other kinds of boilers,
the general arrangement of furnaces and flues being modified to suit par-
ticular forms of boilers and particular localities.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of my Invention; but what I
consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,
First, the general arrangement and construction of steam boilers, as herein-
before described.
Second, the application and use in steam boilers of vertical tapered tubes
communicating with the water spaces and passing through the main flue,
these tubes being arranged with their small ends downwards, as herein-before
described.
Third, the application and use in steam boilers of vertical tubes com-
municating with the water spaces and formed with a transverse sectional
contour, resembling an egg-oval, as herein-before described.
Fourth, the system or mode of obtaining effective tubular heating surface in
steam boilers by the use of tubes of oval or differential transverse section, so
as to produce a superior overlapping or enveloping action of the flame and
heated current.
In witness whereof, I, the said John Mac Farlane, have hereunto set my
hand and seal, this Twenty-third day of November, in the year of our
Lord One thousand eight hundred and fifty-four.
JOHN MAC FARLANE. (L.S.)