IMPROVEMENTS IN THE PRODUCTION OF HOT-AIR GAS, AND IN THE USE OF THE SAME FOR MOTIVE PURPOSES AND FOR ILLUMINATION."
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Andrew Nicol Porteous at the Office
of the Commissioners of Patents on the 15th February 1878.
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ANDREW NICOL PORTEOUS, of Edinburgh, Scotland, Engineer. IMPROVEMENTS
IN THE PRODUCTION OF HOT-AIR GAS, AND IN THE USE OF THE SAME FOR MOTIVE
PURPOSES AND FOR ILLUMINATION."
My Invention has for its object the production of gas from liquid hydrocarbons
by means of hot air, and using such gas in engines for producing motive power
suitable for propelling tramway cars and for other purposes, also in using such gas
for illuminating purposes.
And my Invention consists in forcing air by means of a pump or blower into
a tank, so as to obtain the required pressure therein, then passing air therefrom
under pressure through a furnace, by which it becomes heated to the required
degree, such heated air being then passed through a chamber containing a sponge
or other suitable porous material saturated with paraffin or other suitable hydro-
carbon.
The heated air in passing through the sponge absorbs or evaporates a portion
of the liquid, more or less, according to its temperature and dryness, and regulated
in such quantity as to render the mixture an explosive gas. This gas is thence
passed to the engine, and there expanded to atmospheric pressure and afterwards
exploded, thereby causing a vacuum for the return stroke of the engine, or it may
be regulated in such quantity as to render the mixture an illuminating gas, and
used in works for the purpose of illumination or in the furnace for the purpose of
heating.
The furnace consists of a circular or other suitably formed chamber, around which
are formed jackets or receptacles for the air intended to be heated, and heat is
applied to the furnace by means of any suitable number of gas jets. The gas for
the purpose is taken from an extra chamber in the tank that contains the sponge
or other porous substance capable of becoming saturated with hydrocarbon. The
furnace is also used for exploding the gas in the engine or engines. This method
of producing gas may be applied to existing gas vacuum engines, and when used
for stationary purposes the air may be heated in any convenient furnace.

page_text: The form of engine used, by preference, is a three-cylinder single-acting engine,
fitted with an oscillating plug valve driven by an eccentric from the shaft for the
supply of the gas in such quantity as may be suitable for expansion, and for
reversing the engine or engines. And on each cylinder at the end of the piston
stroke there is a small part fitted with a self-acting valve in order to explode the
gas as required, and these cylinders are also fitted with an exhaust or relief valve
to allow of the escape of the gas down to atmospheric pressure before exploding;
these valves would only be used when starting the engines, as after that the gas
would be brought to atmospheric pressure by expansion in the cylinders alone.
In the adaptation of this engine for the purpose of driving tramway cars, the
supply air would be kept at considerable pressure for the purpose of easily starting
the car at high pressure, and thereafter, by means of the plug valve, expanding to
any grade required.
The air pump is connected to the shaft in such a manner that it can be taken off
when required in going up gradients, or when extra power is required.
The whole machinery is placed underneath the car, and the tank for the supply
of the paraffin or hydrocarbon is placed on the top of the car in any suitable place,
for the purpose of giving a pressure or head to the fall of the liquid.
The machinery is under the control of the driver from both ends of the car by
suitable connections with the engine, air pump, and other parts working in com-
binations therewith.