IMPROVEMENTS IN STEAM CARRIAGES FOR TRAMWAYS AND OTHER PURPOSES
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Thomas Robertson, junior, at the
Office of the Commissioners of Patents on the 16th June 1876.
THOMAS ROBERTSON, junior, of Glasgow, in the County of Lanark, North
Britain, Engineer.
"IMPROVEMENTS IN STEAM CARRIAGES FOR TRAMWAYS AND
OTHER PURPOSES."
This Invention has reference to new or improved modes and means of, or
arrangement of the mechanism for, preventing the escape of black smoke from the
boiler furnaces of steam carriages, and the noise of the exhaust steam escaping
from the high-pressure steam engines and boilers of the said steam carriages, so as
to render these suitable for tramways and other purposes in streets, roads, and
towns, without inconvenience or annoyance to other traffic, or to persons or animals
engaged therein.
And the nature and novelty of the Invention or improvements consist all as
follows:-In the use of one of the best known forms of steam boilers for the quick
raising of steam with a good draught, preferably of the tubular, vertical, or "Davey
Paxman" construction, which would take up the smallest possible surface floorage,
so that it could be set in a side compartment of the carriage with its weight and
that of the engine, fuel, and attendant so near or over the driving traction shaft
as to secure the greatest possible steadiness of the vehicle and frictional tractional
action of the wheels on the rails or roads.
"
The boiler would be fitted with the best ordinary mountings such as a "Cock-
burn or other good safety valve, water and steam gauges, blow-off cocks, and
injector feed arrangements, so that water could be fed into the boiler while the
engine or carriage was standing as well as when running; and under one of my
improvements the boiler is made with a closed-in ash-pit below the fire-grate, so
that all the air required to support combustion is forced in through this close
chamber, preferably by one of "Korting's well-known air blowers," or it might be
by any other jet or constant blower, which would give a nearly uniform blast
without noise.
The engine may be of any of the ordinary types of double cylinder, vertical, or
horizontal engines heretofore used for driving railway, tramway, or road traction
or portable engines; but another improvement consists in leading the exhaust
steam into an air-receiving box fitted to the entrance or air-supply branch of the
blower, so that the force and noise of the exhaust steam would be destroyed in this
chamber, and be utilized in heating and propelling the air into the blower, a trap
being provided in the lower part of this air-supply chamber to receive the hot
[Price 2d.1

page_text: water condensed from the exhaust steam by the air, which is thus heated before
entering the closed ash-pit, and dried in passing up through the grate or furnace
bars and fire thereon.
A hollow conical, cylindrical, or other shaped vertical branch or nozzle is placed
over or through the fire-grate, projecting a foot or more up into the firebox, with a
rose or other perforated top so as to conduct a sufficient current or blast of the
hot air direct from the ash-pit up through and spread it over the fire to mingle
with and burn the gases before they form smoke or escape into the throat of the
chimney or waste gas pipe from the fire-box, which is fitted with the usual throttle
valve or damper.
By these improvements also the hot waste gases (instead of being led into a
chimney direct to the air above) are conducted down through a pipe within a long
feed water trough below the carriage or seats so as to cool the gases before allowing
them to escape close to the ground behind the carriage without noise or smoke, and
at the same time heat the water for the injector. or feed pump to supply to the
boiler.
A good arrangement of the steam cylinders, crank shaft, and other working parts
would be to carry the whole as a horizontal engine on a portable hanging frame
bolted up to the cross beams of the carriage below the floor or platform, a part of
which being made to lift as a trap to allow easy access for lubricating and
tightening the working parts all between the two main axles and, sets of. wheels,
one set of which would be coupled or geared to the, crank shaft of the engine by
spur wheels, while strong brakes would be fitted on the wheels of the other set,
which might be made to act by the power of the steam let into a special cylinder
for the purpose, or worked by a friction clutch from the engine shaft, and when
the force of the exhaust steam from the engine was not desired to be taken advan-
tage of to force the air into the air blower or into the-close ash-pit it might be
made to enter the air chamber or a hot feed water chamber by a trumpet-shape
nozzle pipe or by a double- nozzle pipe which would circulate the water through
them, and in either case soften or destroy the force of the escaping blast, and prevent
the noise usually caused by its free escape into the air.
These improvements in no way interfere with the form or construction of the
carriages further than stated, so that these may be made in all other respects as
heretofore, or as suitable for the particular traffic and purposes desired.