A NEW MODE OF AND APPARATUS FOR UTILIZING HEAT AS A MOTIVE POWER
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Harry Whiteside Cook at the Office
of the Commissioners of Patents on the 7th June 1876.
HARRY WHITESIDE COOK, of Stondon Massey, in the County of Essex, Gentleman.
"A NEW MODE OF AND APPARATUS FOR UTILIZING HEAT AS A MOTIVE POWER."
The essential feature of my Invention is the use of gases produced by, and
remaining over froin the combustion of fuel (either alone or combined with a
supplementary supply of air) to work the piston of an engine. The heating of
these gases and air (or as I shall henceforth call it of the air) may be made to
produce an increase either of volume or of pressure. In the former case the
arrangement will be as follows:-The fuel is placed in a strong closed chamber
supplied with compressed air, and into which chamber air is further forced by
means of a pump or other analogous device.
Means are provided either by valves or otherwise whereby any given proportion
of air may be made to pass through the fuel, so that the amount of combustion and
the mean temperature of the air may be varied at will. If now the heated air be
made to work a piston of the same stroke as the air pump, and if the air be used
expansively so that its mean pressure shall be equal to that in the air pump, its
area must be larger than that of the pump in proportion to the increase of volume
produced by the heat, and this increased area (which represents the total effect of
the heat) represents also the effective power of the engine after working the air
pump; the whole of the heat is thus utilized, whereas in the steam engine about
30 per cent. escapes up the chimney, and 60 per cent. is wasted in evaporating the
water. The present Invention thus secures an economy (as compared with the
steam engine) of 90 per cent.
In stationary engines (where space is not of importance) the same principle of
expansion may be employed in the following manner: The fuel (as before) is
contained in an air-tight chamber and is fed with air by a fan or blower, thereby
producing a certain pressure, and the heated air in passing to the chimney is made
to actuate a windmill working in a closed tube, which indeed may form part of the
chimney itself. A very simple and economical engine is thus obtained, though the
economy of fuel will not be so great as in the former arrangement. If however it
be geared so as to run fast and a rotatory motion be given to the air by properly
disposed diaphragms (as in Fourneyron's turbine) a windmill working in a tube
will transmit about 70 per cent. of the power applied to it, so that such an engine would

page_text: consume per horse power one seventh of the fuel required by a steam engine. It
will thus be evident that in any case the fuel has to burn in a chamber containing
compressed air. In some instances (viz., when an engine is intended to run a
specified time) the chamber may be inade large enough to contain the necessary
supply of fuel. In other cases means have to be provided for introducing the fuel
without allowing the escape of the air; this may be done in various ways, but the
simplest plan is to let the fuel be contained in an upright tube within the air
chainber and extending above it; at the bottom of this tube is a grating for
combustion, so that the coal sinks in the chamber as it is consumed. This tube is
furnished near the top with two valves or air-tight doors, so arranged that either
of them can be opened or closed at will without opening the other, the space
between them can therefore be filled with fuel without letting the air escape; and
then the top door or valve being closed and the bottom one open the fuel will be
ready to find its way to the grate.
Instead of utilizing the increase of volume resulting from the heating of the air
the increase of pressure may be turned to account. In this case the amount of air
introduced by the air pump is limited to the quantity necessary to support
combustion, but on the whole this machine will be more cumbersome than the other
arrangement, and a supply of water will be necessary; as however (in some cases)
such an engine may be convenient I will proceed to describe its action.
The coal is burned in an upright tube as before; there are three closed chambers,
one high pressure, the second low pressure, and the third varying; this third
chamber is connected with the other two, and the air in it is treated alternately
with a jet of flame from the furnace, and a jet of water from a pump, and as the
pressure is thus varied it will alternately suck air from the low-pressure and force
air into the high-pressure chamber, the proper valve being of course supplied
to enable it thus to act as a pump. The surplus air which is continually pumped
in may be allowed to actuate a small auxiliary engine as it escapes. When a very
large cylinder and slow piston movement are employed the the 1st and 2nd
chamber may be dispensed with, and the 3rd chamber connected directly with the
cylinder.