IMPROVEMENTS IN STEAM BOILERS
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, JAMES M°GOWAN M°CULLOCH of 10 Heald Street, Garston, in the County
of Lancaster, Engineer do hereby declare the nature of my said invention for
"IMPROVEMENTS IN STEAM BOILERS," to be as follows:-
This invention has for its object a boiler with very large and effective heating
surface easy of construction and repair with good circulation. It can be arranged
horizontally, vertically, or inclined, but if made vertical the flues do not extend
through the boiler, but join a little below the water level. I will describe it first
for horizontal or inclined boilers, and then afterwards show how to modify the
design where space or other consideration demands a vertical boiler.
This horizontal boiler consists 1st in a furnace flue or flues extending nearly or
quite the full length of the boiler and in height from the bottom or from near the
bottom of the boiler to a little below the minimum water level of the boiler.
2nd in piercing the upper portion of this flue or flues with a series of transverse
slightly inclined and preferably conical water tubes. If there be two furnace flues
they are placed a trifle more than their breadth apart. If there be only one I
leave a space a trifle more than its breadth on one or both sides of it for admitting
and taking out tubes. The return fue consists of a single large flue between the
two furnaces below the level of the lowest transverse tube, or if there be a single
furnace a single flue on each side, or on one side only, but below the level of the
transverse flues, or if desirable a series of longitudinal tubes can take the place of
this return flue or flues. If a single or two large return flues be used, I prefer to
introduce into them a series of vertical or nearly vertical water tubes. The division
between the furnace and the return flue can be a simple removable plate or
partition of iron or fire brick or it could be a water diaphragm if desirable, I
prefer a simple removable plate if the junction between the flues takes place in the
boiler, this partition does not extend to the end and I prefer to form the end of
the flues of a feed heating chamber placed against the boiler to protect the end plate
from the heat and to economise heating space. The furnace and bridge are of the
usual description. A space wide enough for a caulker to work in must be arranged
for at bottom and sides between the tube plate and the shell of the boiler.
The shell is preferably cylindrical but can be of any other suitable design.
If the boiler be very inclined care must be taken to keep the flues below water,
and if vertical the flues must join and end below low water level. To make up for
"

page_text: this shortening of the flues, tubulous portions can be placed on all four sides of the
centre instead of on only two or three sides as in horizontal boilers, as what in
horizontal boilers is the underneath side can be used. The space can be divided
between furnace and return tube as desired, but I prefer a simple diagonal
partition on one side the furnace at bottom opening out into two tubulous wings, &
and half the centre and the return flue being the other half. It can however be
arranged as in horizontal boilers with only two or three tubulous wings. In all
cases whether horizontal, vertical, or inclined there is the main central flue space
with squarish sides and tubulous flue spaces projecting from those sides with the
preferably slightly inclined tubes opening out into the rectangular or nearly 1
rectangular space formed by the tubulous projections from the main flue, and
this arrangement, whatever the form of the boiler, is the main essence of my
invention.

page_text: COMPLETE SPECIFICATION.
I, JAMES MCGOWAN MCCULLOCH, of 10 Heald Street, Garston, in the County
of Lancaster, 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:-
This invention has for its object a boiler with very large and effective heating
surface, easy of construction and repair, with good circulation.
Figures 1 and 2 are transverse and longitudinal sections of a boiler with two
flucs.
Figures 3 and 4 are longitudinal and transverse sections showing a boiler with
one furnace and one return flue.
The invention consists, essentially, first, in a furnace or furnaces extending the
full length of the boiler, and in height from the bottom or from near the bottom
of the boiler to a little below the minimum water level of the boiler; second in
piercing the upper portion of the furnace or furnaces with a series of transverse
slightly inclined and preferably conical water tubes; third in bringing the return
flue or flues back alongside the furnace but below the level of the water tubes in
the furnaco; fourth, in placing a series of preferably conical, vertical or nearly
vertical water tubes through this return flue.
Referring to the drawings; in which like letters refer to like parts throughout,
A is the boiler shell, preferably cylindrical but other forms, if well stayed, could be
used; B furnace preferably round-topped when space admits of it, as in Figures 1
and 2; but in the case of small boilers, where it would reduce the available number
of transverse tubes too much, I make it flat topped, or nearly so, and well stayed
as in Figures 3 and 4, C fire bars of any ordinary construction; D bridge;
E transverse tubes, preferably conical, with bottom surface about level but where
parallel tubes are used I incline them upward somewhat toward the space over the
return Blue. I prefer to so design the boiler that at even the small ends of all
tubes there shall be a vacancy beyond, of about eighteen inches in breadth to
enable a man to go in and calk or unscrew or tighten them. The tubes I prefer to
form with a thread screwed into each tube-plate, and having a nut or nuts at each
end to still further hold the tube and make a tight joint. If nuts be used, the
tubes should be parallel where they enter the tube plate, and a little on each side,
so as to give the nuts fair play. The tubes thus act as stays, 'even though conical.
F combustion chamber common to all flues; G return flue. H vertical tubes,
preferably conical, and screwed at each end into the tube plates, as above
described; I space sufficiently wide and deep to enable a repairer to withdraw the
tubes 'through it, J water space at small or lower end of tubes, preferably about
eighteen inches wide, for working in, K man-hole, L staying devices to prevent
collapse of flue, M water chamber attached externally to back end of flue, forming
a feed heater and chest, where any sediment from the feed water may collect.
Not being a vital part of the boiler, the chest can be renewed at small cost. The
object is further to prevent overheating of the back plate. N is a plate forming
the sides of the ash pit, and separating it from the return flue; it is cast with a

page_text: WP. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
and 323, High Holborn, London,
Patent Agents for the Applicant.
Dated this 21st day of May 1885.
WP. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
and 323, High Holborn, London,
Patent Agents for the Applicant.