CERTAIN IMPROVEMENTS IN STEAM BOILERS OR GENERATORS
Year: 1855

page_text: LETTERS PATENT to William MacNaught, of Manchester, in the County
of Lancaster, Engineer, for the Invention of "CERTAIN IMPROVEMENTS IN
STEAM BOILERS OR GENERATORS."
Sealed the 16th November 1855, and dated the 21st May 1855.
PROVISIONAL SPECIFICATION left by the said William MacNaught at
the Office of the Commissioners of Patents, with his Petition, on the
21st May 1855.
I, WILLIAM MACNAUGHT, of Manchester, in the County of Lancaster,
Engineer, do hereby declare the nature of the Invention for "CERTAIN IN-
PROVEMENTS IN STEAM BOLLERS OR GENERATORS" to be as follows:-
My improvements are effected by placing the furnaces or fire-places
employed in steam boilers or generators above the water line, or within the
upper portion of such boilers or generators, instead of, as heretofore, below it.
Any suitable number of circular flues or tubes of varying or of the same areas
may be used, by which the heat and gases generated in the furnaces are caused-
to be returned through the boiler and beneath the furnaces, and thence, by
any suitable arrangement of flues or brickwork, allowed to escape to the main
shaft or flue.

page_text: Amongst the advantages attained by the adaptation of these improvements
are, great increase of heating surface, additional strength in the boiler, caused
by the longitudinal circular flues or tubes acting as stays, and also the prevention
or consumption of smoke.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William MacNaught in the Great Seal Patent Office on the
20th November 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
MACNAUGHT, of Manchester, in the County of Lancaster, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of May, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William MacNaught, Her especial license that I, the said William
MacNaught, my executors, administrators, and assigns, or such others as
I, the said William MacNaught, my 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
"CERTAIN IMPROVEMENTS IN STEAM BOILERS OR GENERATORS," upon the condition,
amongst others, that I, the said William MacNaught, 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.
NOW KNOW YE, that I, the said William MacNaught, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement and accompanying Drawing (that is to say):-
The principal object of this Invention is to obtain a great amount of internal
heating surface in a steam boiler, combined with simplicity of construction and

page_text: limited length; also to admit the whole external surface of the boiler to be
exposed to the heat, which will be equally applied to the boiler.
My improvements are effected by placing the furnaces or fire-places employed
in steam boilers or generators above the position of the ordinary water line, or
within the upper portion of such boilers or generators, instead of, as heretofore,
placing the furnaces in the lower portion of the boiler or generator. Any
suitable number of flues or tubes and of varying or of the same areas may be
used, by which the heat and gases generated in the furnaces may be returned
through the boiler and beneath the furnaces, and thence, by any suitable
arrangement of flues or brickwork, allowed to escape to the main shaft or flue.
In the construction of my improved boiler, the internal flues or tubes will,
from their size and position, lessen the strain on the ends of the boiler, and
at the same time increase the resisting power, thus dispensing with the use of
longitudinal or "gusset" stays in the construction of flat-ended boilers.
A further advantage attained by the adaptation of these improvements is,
the great increase of heating surface, and also the prevention or consumption
of smoke; and from the comparative shortness of the tubes or internal flues of
this improved boiler, they will be less liable to collapse than the flues in a
boiler of the usual length. Comparing this with the ordinary two-flued boiler,
it will be equal to it in power with the same diameter and one half the
length, and superior to it in economy and safety, and in the more rapid
generation of steam.
In order that my improvements may be more clearly shewn in detail, I have
attached to these presents a Sheet of Drawings, fully illustrating my Invention,
and have marked the same with figures and letters of reference corresponding
with the following description thereof, similar letters indicating corresponding
parts of the boiler, &c. in all the Figures.
Fig. 1 of the annexed Drawing represents a longitudinal section of the
boiler through the line a, b, in Fig. 2; Fig. 2 represents a plan of the same
with the upper part of the brickwork removed; Fig. 3 represents a transverso
section of the boiler through the line c, d, in Fig. 2; Fig. 4 represents a front
view of the boiler. The remaining parts of the Drawing represent different-
modifications of the same principle, and will be more particularly described'
hereafter.
The boiler, represented by Figs. 1, 2, 3, and 4, is intended to be made with
a shell e, e, e, about the diameter used in the construction of the double-flued.
boiler, but with this difference, about one-half its usual length, and to have two
internal flues ff, placed in the upper part of the boiler, and having three

page_text: return flues in the under part of the boiler, represented in the Drawings by
9.9.9, space being allowed between the upper and under flues for a man to get
between them by the man-hole door to clean or repair when required. The
upper flues f,f, are intended to be used as the furnaces or firing flues, and the
under flues g, 9, 9, as the return flues. The boiler is represented with the usual
mounting and two domes, in one of which the man-hole is to be placed for
obtaining access to the upper part of the boiler.
The flame or heat, after passing through the flues f,f, returns through the
flues 9,9,g, then passes through one of the under flues 7, 1, and returning
through the other, the flame or heat passes to the flue m, exposing the upper
part of the boiler to the action of the heat, and thence it passes through the
damper frame to the main flue and chimney, thus exposing the whole of the
external surface of the boiler (except that in immediate contact with the brick-
work, to the action of the heat, and twice the surface for a given length usually
obtained in the ordinary two-flued boiler.
The size and position of the internal flues, by exposing a diminished surface
in the ends to the pressure of the steam, and at the same time adding to their
resisting power, will obviate the necessity of employing stays (longitudinal or
gusset) in the construction of the boiler.
Although the foregoing description refers to a boiler with two internal flues
above, and three below, I do not confine myself to carrying out my Invention
in this manner exclusively. The size and number of the flues may be altered
and varied, as for example: In the annexed Drawing, at Figs. 5, 6, and 7 is
represented a Drawing of a boiler with one internal flue for firing, and five
internal return flues; and instead of two steam domes, a longitudinal tube or
steam chamber is fixed over the boiler; also at Fig. 8 is represented a boiler
constructed with two upper internal flues for firing, and a multitude of small
tubes for returning the flame or heat; or might be constructed with one return
flue, as shewn at Fig. 9. In all cases it is intended to keep the boiler quite
or nearly full of water, and expose the whole of the external surface to the
action of the heat.
Having now described the nature of my said Invention, and the manner in
which the same is to be performed, I desire it to be understood that I claim
the general arrangement or construction of steam boilers or generators
exhibited in the several Figures of the Drawing annexed, and herein-before
fully set forth and described, whereby I am enabled, from the position of
the internal tubes or flues in such boilers, to obviate the necessity of employing
either longitudinal or gusset stays in the construction of flat-ended high-

page_text: pressure boilers, and whereby I am also enabled to place the furnaces or
fire-places in the uppermost flues or tubes, by which means the heat and
gases generated in the furnaces may be returned through the lower tubes
also within the boiler, and underneath the said furnaces or fire-places.
In witness whereof, I, the said William MacNaught, have hereunto set
my hand and seal, the Nineteenth day of November, in the year of our
Lord One thousand eight hundred and fifty-five.
WM M NAUGHT. (L.S.)