IMPROVEMENTS IN STEAM BOILERS
Year: 1884

page_text: I, GRAHAM STEVENSON, of the Airdrie Engine Works, Airdrie, in the County of
Lanark, North Britain, Engineer, do hereby declare the nature of my said
invention for "IMPROVEMENTS IN STEAM BOILERS," to be as follows:-
My said Invention comprises improved heating surface combined with improved
arrangements for securing thorough combustion of the fuel employed. The boiler
is composed of an upper vessel of a horizontal cylindrical or other convenient form
to contain some water whilst its upper part forms the steam space. The principal
heating surface consists of large tubes with the water inside of them and which are
attached by their upper ends to the upper vessel. The tubes, which are made and
fixed in an improved manner hereinafter described, extend down vertically or
nearly so across two horizontal flues, and projecting through the lower horizontal
partition of the bottom flue have mud pockets screwed on their lower ends, which
pockets can be removed periodically for cleaning purposes. The furnace is placed
at one end at a little distance below the upper vessel, and from its inner end a
short flue extends forwards above it, and at its forward end communicates with
the upper of the two flues hereinbefore referred to. The short flue above the
furnace forms a combustion chamber in which the heat of the fire gases .becomes
thoroughly developed before the gases impinge on the comparatively cold metal
surfaces of the boiler, the complete combustion of the gases being insured by air
admitted at the inner end of the combustion flue or chamber. The fire gases pass
along the upper flue immediately under the upper vessel and amongst the upper
parts of the tubes to the back end, and then return along the lower flue amongst
the lower parts of the tubes. From the front end of the lower flue the fire gases
pass along a higher flue over the upper vessel to the chimney.
The tubes are about four inches in diameter but have their ends reduced by
cressing and drawing or forging to a diameter of about two inches. Each tube is
fitted in a conical hole in the upper cylinder or vessel of the boiler and is fixed by
a nut screwed upon the end projecting into the vessel. The nut is made with a
narrow or sharp cylindrical flange which bears on the plate or shell and which
indenting the latter slightly insures a tight joint. Instead of having the part of
the tube passing through the plate or shell conical it may be cylindrical, and nuts
with the sharp cylindrical flanges may be applied on both sides of the plate; or a
shoulder may be formed on the tube to bear on the outside of the plate. Those
tubes which are fixed to curved or inclined parts of the shell of the upper vessel
have their necks or upper ends bended so as to pass normally through the shell.
Dated this twenty-eighth dow of July 1884

page_text: COMPLETE SPECIFICATION.
: I, GRAHAM STEVENSON, of the Airdrie Engine Works, Airdrie, in the County, of
Lanark North Britain, Engineer, do hereby declare the nature of my said invention
for "IMPROVEMENTS IN STEAM BOILERS" and in what manner the same is to be
performed, to be particularly, described and ascertained in and by the following
statement, that is to say :-
My said Invention comprises improved heating surface combined with improved
arrangements for securing thorough combustion of the fuel employed.
A sheet of explanatory drawings is hereunto appended on which figures, 1, and 2,
are transverse and longitudinal vertical sections of a steam boiler and furnace
arrangements made according to my Invention whilst figures, 3, 4, and 5, are
enlarged sections of parts of tubes forming part of the heating surface.
The boiler is composed of an upper vessel, 6, of a horizontal cylindrical (or it
might be of other convenient form) to contain some water whilst its upper part
forms the steain space. The principal heating surface consists of large tubes, 7,
with the water inside of them and which are attached by their upper ends to the
upper vessel. The tubes, 7, which are made and fixed in an improved manner
hereinafter described, extend down vertically or nearly so across two horizontal
flues, 8, 9, and projecting through the lower horizontal partition, 10, of the bottom
flue, 9, have mud pockets, 11, screwed on their lower ends, which pockets can be
removed periodically for cleaning purposes. The furnace, 12, is placed at one end
at a little distance below the upper vessel, and from its inner end'a short flue, 13,
extends forwards above it, and at its forward end communicates with the upper, 8,
I of the two flues herein before referred to. The short flue, 13, above the furnace, 12,
forms a combustion chamber in which the heat of the fire gases becomes thoroughly
developed before the gases impinge on the comparatively cold metal surfaces of the
boiler, the complete combustion of the gases being insured by air admitted by
passages, 14, at the inner end of the combustion flue or chamber, 13. The fire gases
pass along the upper flue, 8, immediately under the upper vessel, 6, and amongst
the upper parts of the tubes, 7, to the back end, and then return along the lower
flue, 9, amongst the lower parts of the tubes, 7. From th efront end of the lower
flue the fire gases pass up side flues, 15, up to and along a higher flue, 16, over the
upper vessel to the chimney.
The tubes, 7, are about four inches or somewhat more in diameter but have their
ends reduced as shown in figures, 3, 4 and 5, by cressing and drawing or forging
to a diameter of about two inches. Each tube, 7, is fitted in a conical hole in the
upper cylinder or vessel, 6, of the boiler and is fixed by a nut, 17, screwed upon
the end projecting into the vessel as shown in figure, 3. The nut, 17, is made with
a narrow or sharp cylindrical flange which bears on the plate or shell, 6, and which
indenting the latter slightly insures a tight joint. Instead of having the part of
the tube, 7, passing through the plate or shell, 6, conical, it may be cylindrical,
and nuts, 17, 18, with the sharp.cylindrical flanges may be applied on both sides of
the plate, 6, as shown in figure, 4, or a shoulder, 19, may be formed on the tube, 7,
to bear on the outside of the plate, 6, as shown in figure, 5. Those tubes, 7, which

page_text: are fixed to curved or inclined parts of the shell of the upper vessel, 6, have their
necks or upper ends bended so as to pass normally through the shell.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare that what
I claim is
1-The combination of parts forming the improved steam boiler substantially
as hereinbefore described and as shown in figures, 1, and 2, of the accompanying
drawings.
2-The improved heating surface formed by the large tubes having water inside
of them, and connected to the larger vessel by contracted ends or necks curved to
enter the said vessel normally substantially as hereinbefore described.
3-The mode of securing the tubes to the larger vessel by nuts made with
narrow or sharp cylindrical flanges substantially as hereinbefore described.
'
EDMUND HUNT,
Applicant's Agent.