IMPROVEMENTS IN GENERATORS FOR COMBINED STEAM AND CALORIC ENGINES
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents, with his Petition, on the
14th October 1874.-A communication from abroad by Pierre
Augustin Samuel, of Paris, France.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN GENERATORS FOR COMBINED STEAM
AND CALORIC ENGINES," to be as follows:-
This Invention relates to improvements in generators for combined
hot air and steam engines.
The difficulty of controlling these generators or boilers has hitherto
prevented their general use, as the hot air and products of combustion
often attain a temperature of 1,300 degrees Fahrenheit, which causes
the parts of the engine to chafe and become set fast, or, as sometimes
happens the water comes into contact with and extinguishes the fire.
According to the present Invention the combination of the steam, air,
gases of combustion is effected on an entirely novel principle, which
is free from the objections above alluded to..
and

page_text: through the valves, and prevent the same passing off with the steam, as
well as to prevent priming.
The boiler is further provided with all the usual adjuncts, such as
water and pressure gauges safety valve, although not shown in the
.Drawing.
The whole being arranged as described the following is the action of
the boiler:―The covers c, f, are removed and the furnace chamber 6
filled with fuel, which is then ignited, and sufficient steam is formed in
boiler a in the usual way to work the engine, as also the feed pump and
pump to supply air beneath the grate for combustion. The covers c, f,
are then put on, whereupon the interior of furnace chamber 6 acquires a
pressure superior to that of the boiler, exceeding it by, for example,
1/10 th of an atmosphere. This excess of pressure destroys the equilibrium
and thus opens valves m and allows the heated air and products of
combustion to escape into the water, by which they are deprived of their
excess of caloric, the temperature of the water being correspondingly
increased.
The springs n of the valves are arranged to open under a pressure of
10 th of an atmosphere in excess, but will immediately close the valves
on the pressure in the furnace being reduced by the escape of the air
and heated gases. On the closing of the valves the pressure in the
furnace again increases, and the valves again open as before, and
so on.
From the foregoing it will be understood that the steam, air, and
heated gases at the upper part of the boiler have an equal temperature,
or in other words the equalization of the temperature is not effected by
the mixing of the steam with the air and gases, but the steam, air, and
gases pass off from the water at the same temperature. In this manner
the temperature of the air and heated gases can never exceed that
corresponding to the pressure in the boiler.
Any kind of fuel, either solid or liquid, may be used, and instead of
having a continuous mechanical feed for the fuel it is preferable to have
two similar furnaces in connection with the same boiler, so that while
the one is being charged with fuel the engine need not stop working,
This arrangement is illustrated in the central vertical section, Figure 5,
the same reference letters being used for indicating the same parts as in
the preceding Figures.

page_text: In this arrangement it will be seen that the same principle is
employed, the boiler A, A, being however independent, while it com-
municates with the furnaces 6 by pipes as before. In this case the
valves m close by their own gravity instead of by springs as before, their
weight being so calculated that they will open when the pressure in the 5
furnace exceeds by 10 th of an atmosphere that in the boiler.

page_text: LONDON Printed by GEORGE. EDWARD EYRE and WILLIAM SPOTTISWOODE
Printers to the Queen's most Excellent Majesty 1875