IMPROVED MEANS OF AND APPARATUS FOR INCREASING THE ILLUMINATING POWER OF COAL GAS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by John Macdonald at the Office of the
Commissioners of Patents on the 4th November 1880.
JOHN MACDONALD, of Queen Victoria Street, in the City of London. "IMPROVED
MEANS OF AND APPARATUS FOR INCREASING THE ILLUMINATING POWER OF COAL
GAS."
The object of this Invention is to cause coal gas to be enriched by passing it
through or over a carburetting material (such as gasoline, for example) in such a
manner as to allow only a small portion of the carburetting material to be exposed
to the action of the gas at a time, by which the illuminating power of the
carburetting material remains uniform throughout, instead of deteriorating after
being exposed to the action of the gas for a short time, as heretofore, also a
means whereby coal gas saturated with hydrocarbon vapour is rendered a permanent
gas.
In order to effect the above I construct an apparatus substantially as follows:-
I employ a closed chamber having an inlet and outlet pipe, and containing one
or more tubes tapered towards the bottom; these tubes extend to about an eighth of
an inch of the bottom of the aforesaid chamber, the outlet at bottom of the
tubes being very small, and having a suitable valve to close them automatically
during charging. Around the tubes I place sponge or other suitable absorbent
material in such a manner that the latter is continually kept saturated by the
action of the hydrocarbon, as hereafter described. Around the aforesaid chamber I
fix a water tight jacket in such a manner as when filled with water or other suitable
liquid it prevents any leakage of the hydro-carbon.
Having first charged the tubes in the aforesaid chamber with the carburetting
material I close the tube, which causes the valves at the bottom to open
and allow a sufficient portion of the carburetting material to pass into bottom of
the chamber and saturate the sponges therein. I then allow the gas to pass through
the inlet pipe and make its way through and between the sponges and tubes, thus
allowing it to absorb sufficient and uniform quantity of carburetting material to
enrich it and increase its illuminating power. In order to render the coal gas
(saturated with the vapor of the hydrocarbon employed) permanent I subject such
saturated gas to a heat sufficient to convert it into a permanent gas. For this
purpose I cause the said saturated gas to pass through a series of pipes or tubes in

page_text: the form of a coil by preference; this series of pipes or coil I surround with a
casing of metal or other suitable material (where sheet iron is employed
this casing is jacketted so that the space within the jacket may be filled with a
material being a non-conductor of heat). I then fill in and around the series of pipes
or coil with asbestos or other suitable non-combustible material, and beneath I fix
a Bunsen or other suitable gas burner, in such a manner that the flame from the
burner when lighted may permeate the non-combustible material so as to heat the
series of tubes or coil and keep saine at at constant heat sufficient to decompose
the hydro-carbon vapour.
The coal gas is thus permanently enriched, so that no condensation from any
change of temperature takes place in the pipes, which is unavoidable when simply
a mechanical mixture of the coal gas and hydrocarbon vapour is made by the
ordinary method of carburetting. Instead of heating the tubes or coil as above
described, they may be otherwise suitably heated.
When the above named means are not employed to decompose the hydrocarbon
vapour, in this case, in order to prevent condensation in the pipes, I connect to
the outlet of aforesaid carburetting chamber another chamber containing an
absorbent material, cuttings of Turkey sponge, by preference, which may be
renewed from time to time. When sponge is employed I place it in such a way as
to prevent contact with any metal that may be employed.
I may employ one or more of these absorbing chambers as found desirable
according to the distance the carburetted gas has to travel.