Improvements in Steam Boilers.
Year: 1888

page_text: Date of Application, 27th Dec., 1888
Complete Specification Left, 27th Sept., 1889-Accepted, 2nd Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in Steam Boilers.
I, WILLIAM DUFF, 20 Saint Vincent Crescent, in the City of Glasgow, Engineer,
do hereby declare the nature of this Invention to be as follows:-
This Invention relates to improvements in steam boilers having for object to ensure
better combustion of the fuel used in the furnaces and more complete utilization
of the heat generated thereby for generating steam whilst making provision for
heating and causing circulation of the water lying in proximity to the bottom of
the boiler and thereby, more especially in the case of Marine boilers, avoiding
leakage and deterioration of the structure occasioned by unequal expansion of the
boiler plates.
In carrying out the Invention I provide the boiler with two or more, but preferably
two, furnaces or fire grates the said furnaces terminating in flues, or as is preferred in
a single flue, extending to the rear of the boiler and communicating through a
chamber with return tubes in the upper part of the boiler as in an ordinary marine
boiler. The return tubes instead of communicating with the usual "uptake" lead
into a gas chamber or "downtake" in front through which the fire gases passing
from the furnaces by the flues and return tubes are led into a flue constituting a gas
furnace extending through the boiler in proximity to the bottom and in a space under
and intermediate between the fire grate flues and communicating at the rear with a
chimney or funnel. This gas furnace or flue is divided by a water space which may
extend throughout its length, or by cross tubes, to provido for rapid heating and
circulation of the water in the lower part of the boiler; and the gas furnace is fitted
with a wedge fire brick to serve the two-fold purpose of protecting the boiler shell
from direct action of the heat and of dividing the flame and directing it against the
sides of the flue. Air to effect combustion of the gases led by the return tubes into
the gas chamber in front of the boiler is supplied through tubes provided with
regulating valves and led down by ventilators from the decks when on board ship
or it may be supplied by fans or blowers when it is desired to employ forced
draught.
In practice the fire grates will be supplied alternately with solid fuel so that the
bulk of the smoke generated in firing may be consumed in the furnace flue or flues
whilst the unconsumed gases flowing through the return tubes into the gas chamber
in front will be therein ignited on meeting with the air supplied thereto and the
resultant flame will be carried through the lower or gas furnace flue of the boiler.
Dated this Twentyfourth day of December 1888.
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in Steam Boilers.
I, WILLIAM DUFF, 20 Saint Vincent Crescent, in the City of Glasgow, Engineer,
do hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement :-
This Invention relates to improvements in steam boilers having for object to ensure
better combustion of the fuel used in the furnaces and more complete utilization of
the heat generated thereby for generating steam whilst making provision for heating
and causing circulation of the water lying in proximity to the bottom of the boiler

page_text: and thereby more especially in the case of marine boilers avoiding leakage and
deterioration of the structure occasioned by unequal expansion of the boiler plates.
As represented in elevation at figure 1 and in longitudinal section at figure 2 of
the accompanying drawings the improved boiler is provided with two or more, but
preferably two, furnaces or fire grates AA the said furnaces terminating in flues B B or
in a single flue or combustion chamber C at the rear of the boiler and communicating
through said chamber with return tubes D D'in the upper part of the boiler as in
an ordinary marine boiler. The return tubes.D D instead of communicating with
the usual uptake" lead into a gas chamber or "downtake" E-in front through
which the fire gases passing from the furnaces by the flues and return tubes are led
into a flue F constituting a gas furnace extending through the boiler in proximity to
the bottom and in a space under and intermediate between the fire grate flues B B and
communicating at the rear with an uptake G leading to the chimney or funnel. This
gas furnace or flue F is fitted with cross water tubes H, to provide for rapid heating
and circulation of the water in the lower part of the boiler, or as represented at.
figures 3 and 4 the flue F may be divided by a water space I extending throughout
its length, a wedge fire brick J being fitted in front to serve the two fold purpose of
protecting the front shell of the water space from direct action of the heat and of
dividing the flame and directing it against the sides of the flue F. Air to effect
combustion of the gases led by the return tubes D into the gas chamber E in front
of the boiler is supplied through a perforated tube or tubes L provided with regulating
valves and led down by ventilators from the decks when on board ship or it may be
supplied by fans or blowers when it is desired to employ forced draught.
In lieu of the large flue F fitted with cross tubes or a water space as described
the number of large fire tubes K may be carried through the lower water space
of the boiler from the downtake in front to the uptake at rear as represented at
figures 5 and 6.
In practice the fire grates will be supplied alternately with solid fuel so that the
bulk of the smoke generated in firing may be consumed in the furnace flue or flues B
and combustion chamber whilst the unconsumed gases flowing through the return
tubes Dinto the gas chamber E in front will be therein ignited on meeting with the
air supplied thereto through the air pipe L and the resultant flame will be carried
through the lower or gas furnace flue of the boiler a small grating e being fitted
at the bottom of the gas chamber E on which burning fuel is placed to ignite the
flame at starting.
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 :-
A steam boiler formed with a gas chamber in front to receive the fire gases
passing through the return tubes, means for supplying air to effect combustion of
the unconsumed gases and a gas flue or flues in the bottom of the boiler through
which the gas flame passes to an uptake at rear substantially as and for the purpose
set forth.
Dated this Thi
L
1
2
1000
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.