IMPROVEMENTS IN APPARATUS FOR PRODUCING COMBUSTIBLE GASES, PART OF WHICH IMPROVEMENTS ARE APPLICABLE FOR INDICATING THE PRESSURE OF GASES AND FLUIDS GENERALLY
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Charles William Siemens at the
Office of the Commissioners of Patents, with his Petition, on the 10th
June 1864.
I, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street, West-
minster, in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS FOR PRODUCING COMBUSTIBLE GASES,
PART OF WHICH IMPROVEMENTS ARE APPLICABLE FOR INDICATING THE PRESSURE OF
GASES AND FLUIDS GENERALLY," to be as follows:-
My Invention has for its object the entire conversion of the combustible
matter in coal or other fuel into gases suitable for heating and lighting
purposes. For this purpose the fuel is made to descend gradually through
one or more vertical or inclined retorts formed of cast iron, fire-brick, or other
suitable material, and is made to pass from the lower end of such retort or
retorts over or upon a fire-grate, where it enters into combustion. The
thickness of the layer of fuel upon the grate being comparatively large, the
oxygen of the atmospheric air which enters through the grate takes up
sufficient carbon to form carbonic oxide, which is a combustible gas. The
mixture of carbonic oxide and nitrogen resulting from this combustion passes
round or over the external surface of the retort, through which the fuel
descends, and imparts sufficient heat to the same to effect the partial or entire
carbonization of the fuel during its descent; the gases thereby evolved in the

page_text: retort also descend to the foot of the same, where they mix with the carbonic
oxide and other gases which are generated upon the grate. Or the gases
generated in the retort may be conducted away separately, and may be
rendered available for illuminating or other purposes where a comparatively
rich hydrocarbon gas is required. The efficient working of this apparatus
depends in a great measure upon an accurate adjustment of the pressure in
different parts of the apparatus. Thus, at the fire-grate, the gas pressure
must be inferior to the atmospheric pressure in order to insure an indraught
of atmospheric air, whereas in the flues and passages surrounding the retort
or retorts, and leading to the gas furnace, the pressure of the gas must exceed
the atmospheric pressure, to prevent indraught of atmospheric air through
unavoidable crevices in the surrounding brickwork. Again, in drawing off
illuminating gas from the retort, it is necessary to regulate its flow, so as to
prevent the inferior gases formed at the lower extremity of the retort from
ascending and mixing with the same. In order therefore to be able to
regulate the fuel upon the grate, and the exit valves for the gases, so as to
fulfil the above-mentioned conditions, it is necessary to obtain indications at
different points of the apparatus of the existing gas pressure. These differences
of pressure are so exceeding small that none of the existing pressure gauges
would indicate them. I effect however the desired object by attaching to the
apparatus at various points a syphon pipe of glass, each leg of which terminates
in a bulb or reservoir, one of which reservoirs communicates with the interior
of the gas producer, and the other with the atmosphere. The lower portion
of the two legs of the syphon contains water, spirits of wine, ammonia solution,
or other suitable liquid, while the upper portions of the syphon legs and a
portion of the two bulbs or reservoirs above mentioned contain another liquid,
such as oil of turpentine of slightly inferior density than the liquid in the lower
portion of the syphon, and of such a nature that the two liquids will not mix.
One of these liquids contains a suitable coloring matter for the purpose of
showing clearly the limits of the two liquids in the tubes. A very slight
excess of pressure upon the large area of liquid in the reservoir at the top of
the one leg or the other of the syphon will cause the points of juncture of the
liquids in the tubes to move through a considerable distance, proportionate
to the difference of pressure, in order to effect the necessary displacement
from the one reservoir to the other; or the two liquids may be so divided that
one reservoir and part of one leg of the syphon contains the one liquid, while
the second reservoir and the remaining portion of the syphon is filled with the
other liquid of comparatively greater density. In this arrangement of the
apparatus only one point of juncture between the two liquids exists, the motion

page_text: of which is read upon a scale. This arrangement of a transparent syphon
with two reservoirs, and two kinds of liquid of different colour and density,
may also be employed irrespective of the other part of my improved apparatus
for indicating slight statical and dynamical pressures of gases and fluids
generally.