IMPROVEMENTS IN GAS ENGINES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Charles William Siemens at the
Office of the Commissioners of Patents, with his Petition, on the 28th
July 1862.
I, CHARLES WILLLAM SIEMENS, of No. 3, Great George Street, Westminster,
in the County of Middlesex, do hereby declare the nature of the said. Invention
for "IMPROVEMENTS IN GAS ENGINES," to be as follows:-
My Invention has reference to that class of engines in which motive power
is obtained by the expansive action resulting from the combustion of a mixture
of an inflammable gas or of inflammable gases or vapours and atmospheric
air within a closed chamber or cylinder, of which class of engines several
varieties have been described by me in the Specification to former Letters
Patent granted to me, and bearing date the 28th August 1860, No. 207.4.
One part of my present Invention consists in certain improved means of
igniting the mixed gases and atmospheric air as they enter the combustion
chamber or cylinder. The combustible gases employed (which may be gene-
rated in the manner described in the Specification to the herein-before men-
tioned Letters Patent already granted to me, or in any other known. manner,)
and atmospheric air are forced, by means of a pump or pumps, into a strong
receiver or reservoir in such proportions as to constitute a combustible or
explosive mixture. The pressure maintained in the reservoir should exceed
the working pressure to be attained in the combustion chamber or chambers.
which are connected with the working cylinder or cylinders. A small quantity
of the explosive gaseous mixture is caused to flow continuously into the

page_text: working cylinder or cylinders, entering, firstly, through an exceedingly small
aperture, admitting of mechanical adjustment, into a tube of a somewhat larger
diameter than this aperture, and thence passing through a rose head or divided
aperture into a passage or channel, formed in refractory material, in which
the mixed gases are ignited and continue to burn, and whence the flame
resulting from this combustion issues in the form of a small jet into the
passage or chamber where it is required to effect the periodical combustion of
the greater volumes of the explosive gaseous mixture that are employed for
working the engine. This igniting jet may be caused to vary in its intensity
during each stroke of the engine so as to reach a maximum of volume at the
moment when the ignition of the gases working the engine is to take place.
Another part of my Invention consists in lining that portion of the working
cylinder or cylinders in which the combustion of the gases takes place, or into
which the products of this combustion enter, with plumbago, fire-clay, or other
refractory material, as also in covering that part of the working piston or
pistons which comes in contact with the flames or bot products of combustion
with refractory material. By these means the gases can expand behind the
working piston at a higher temperature than could otherwise be maintained,
and the entire or perfect combustion of the gases employed will be also more
fully insured, whence greater power and economy will result.
Another part of my Invention has reference to the mode of admitting the
combustible gases and air into the working cylinder, and of discharging the
products of combustion therefrom after-expansion.
In working my improved gas engines I prefer to discharge the whole of the
products of combustion, into the atmosphere after they have served to propel
the working piston; but in order to save a portion of the sensible heat of such
products of combustion I prefer to dischargo the same through a regenerator
or chamber, filled with metal or other good conductor of heat, presenting a
considerable amount of surface for the absorption of the heat of the gases.
The combustible gases and air required to effect the succeeding working
stroke of the same piston are passed, either separately or combined, through
the same regenerator in the opposite direction, in order that they may take up.
the heat there deposited previous to their combustion taking place. Ordinary
slide or other valves aro employed to regulate the admission of the combustible
gases into the working cylinders, as also the discharge of the products of com-
bustion after expansion. As herein-before mentioned, the combustible gases
and air employed for working the engine have to be considerably compressed
before entering the working cylinders. For this purpose the end of the
working cylinder or cylinders which does not receive the heated products of

page_text: combustion may be closed and provided with valves so as to constitute a pump
or pumps, serving to force the gases either directly into the heated end of
another working cylinder, if four such are employed combined in one working
system, or into a reservoir, whence they are admitted, at proper intervals,
through slide or other valves, as before-mentioned, into the same or other
working cylinders; or a separate pump or pumps may be employed for the
compression of the gases. I sometimes admit water with the gases into the
pumping cylinder or cylinders for the several purposes of cooling and lubri
cating the same, and of generating, by the heat evolved in compressing the
combustible gases, the vapour of water, which it is found enhances the effect
of the gases in combustion. The excess of water accumulating in the receiver
is allowed to pass back to the pump through a contracted orifice, thus
performing a circuit. The valves and pumps and other working parts of the
engine may be advantageously surrounded with cold water, which may be
gradually changed, so as to keep those parts cool.
Another part of my Invention consists in certain improved means for pre-
venting the destruction of the reservoir through an accidental explosion of the
combustible gas and air, when these are contained therein in the form of an
explosive mixture. For this purpose I provide the reservoir with an aperture,
closed by means of a curved plate or cover of very thin and tough metal,
which, in case of an accidental explosion, as before-mentioned, will not oppose
the inertia of a great mass to counteract the sudden increase of pressure
produced, as is the case with ordinary safety valves, but which will readily
yield to any increase of pressure sensibly exceeding the usual working pres-
sure, thereby preventing the risk of the reservoir itself being destroyed.
Instead of igniting the mixture of combustible gas and air for working my.
improved gas engine by means of the arrangement herein-before described,
I sometimes employ an electric spark for this purpose, or I employ the
arrangements as described in the Specification to the herein-before mentioned
Letters Patent already granted to me.