IMPROVEMENTS IN THE CON- STRUCTION OF STEAM BOILERS OR GENERATORS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Julius Drewsen and Robert Bruce
Smith at the Office of the Commissioners of Patents on the 14th January
1878.
JULIUS DREWSEN and ROBERT BRUCE SMITH, both of Glasgow, in the County of
Lanark, North Britain, Consulting Engineers. "IMPROVEMENTS IN THE CON-
STRUCTION OF STEAM BOILERS OR GENERATORS."
This Invention has reference specially to improvements in the construction of
horizontal internal furnace and flue steam boilers or generators, for the purpose of
giving them greater furnace and heating surface, and a more perfect circulation
of the water, with greater facilities for inspecting and repairing the tubes and
concealed or enclosed parts; these improvements and boilers being either suitable
for land or marine purposes or service.
And the nature and novelty of the Invention or improvements consist,--
First. Under one modification or arrangement in forming the outer shell of a
long horizontal cylindrical shape with ends all as usual, but with three cylindrical
furnace flues formed in the front end, extending back to the central end or division
plate at the back of the furnaces or flame bridges, all leading into one large
cylindrical flue jointed to the said middle dividing end or plate, and led back
and rivetted to the back end plates of the boiler, all these parts being fitted
sufficiently low in the main outer case to allow a usual water space below, between
them and the outer case, and also be quite covered with water on the top when the
boiler is filled within a foot or inore of the top, fitted with one or more steam
receivers, preferably made cylindrical, with domed ends, and laid parallel to and
over the outer shell, and jointed to the steam space at top by two branches towards
the ends.
A further improvement consists in fitting within the large back flue a long
cylindrical water-heating and circulating chamber, either concentrically or eccen-
trically thereto, and continued out beyond this flue and the main shell across. or
through the flue at the back of the boiler leading to the chimney, but having the
upper and lower space between this water heater and the interior of the back flue
filled with small radiating water-heating and circulating tubes above and below,
leaving a narrow radial space on each side between the upper and lower set of tubes

page_text: for convenience of access for inspection and cleaning. The ends of all these tubes
can be easily got at for expanding and fixing them as usual, except a very few at
the centre of the lower water space, where they may have screw nuts, all easily got
When this central water vessel
at for plugging or removal when a leakage occurs.
is arranged eccentrically in the back flue it would be set near the lower side, and
connected to the lower water space by two large water branches for the water to
circulate up through to pass into the set of small water tubes, all set radially round
and across the widest part of the eccentric flue space above the water vessel, with an
open space below the shortest tubes on each side, and this back water vessel and
space between the furnace flues may be connected by a central water tube or branch,
which would allow direct circulation below, between these water spaces, and act as a
stay also between their end plates.
By a third arrangement the large central back flue might be formed right through
from the front to the back end of the boiler or outer shell, and have one large fire-
grate and furnace chamber fitted in the front part or end in front of the new central
water vessel and radial heating tubes, instead of their ordinary sized ones as in the
former arrangements. This large front furnace flue part (where there are no heating
cross tubes to strengthen it) and also the outer shells are both constructed with
outer welded rings, which give additional strength and security to these new or
improved constructions of boilers.
The main improvements consist in placing within the back flues of steam boilers
or generators a central water-heating vessel concentrically or eccentrically with
radiating water-heating and circulating tubes between these joining the main water
space of the boiler, giving the greatest heating surface with the greatest strength
of tubes, flues, and ends, with less body of water, all important advantages.
Suitable man-hole doors would be fitted on the end of the new and ordinary
water spaces for getting at the tubes for instection and repair, and safety valves
and other ordinary mountings would also be fitted to these improved steam
generators.