IMPROVEMENTS IN APPARATUS FOR GENERATING STEAM
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by George William Hart at the
Office of the Commissioners of Patents, with his Petition, on the
27th January 1873.
I, GEORGE WILLIAM HART, of 11, Palace Road, Upper Norwood, in
the County of Surrey, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN APPARATUS FOR GENERATING STEAM," to be as
follows:-
I construct a furnace chamber which may be lined with fire-clay and
I place such chamber by preference in the centre of the boiler, where a
vertical boiler is used, and in longitudinal boilers such as those of
locomotives, or whenever it may be more convenient to construct the
boiler longer in horizontal measurement than vertically, then the
furnace may be placed in any desired part of the interior of the boiler.
The upper end of the furnace terminates in a combustion chamber which
is separated from the steam chest and other portion of the boiler by a
tube plate through which a number of tubes pass into the water, these
tubes are open at both ends and the lower ends thereof are consequently
filled with water; when the steam is to be employed in obtaining

page_text: motive power, the steam or combination of gaseous products and steam
pass off by a steam pipo to the cylinder and piston as in ordinary
engines, and as the pressure in the steam chest is less than in the com-
bustion chamber the gaseous products of combustion descend through
the tubes into the water in the boiler, thereby coming into direct contact|
with the water, whereby a rapid generation of steam is created, which
passage downwards of the highly heated products of combustion
continues so long as there exists a difference of pressure between the
combustion chamber and the steam chest, and to provide against the
pressure becoming greater in the steam chest than in the combustion
chamber there is a valve opening upwards from such steam chest into
the combustion chamber, so that the water cannot be forced upwards
into it. The exhaust pipe from the cylinders of the engine may either
lead to a condenser or into the atmosphere as in non-condensing engines.
Motion is given from the engine to an air pump which forces into the
furnace the necessary supply of air for combustion, and also when
requisite to another pump to inject the liquid fuel into the furnace
chamber, or where a gas is used as fuel this pump condenses it to an
equal or slightly higher degree of pressure than that existing in the
furnace and combustion chamber. When liquid hydrocarbons or oils
are used I prefer to allow such to enter the furnace chamber by force of
gravity, which I effect by connecting the upper portion of the reservoir
in which such hydrocarbon or oil is contained with the steam chest so
that the pressure may be equal in the reservoir, and in the steam chest
a piston may be interposed between the surface of the hydrocarbon and
the steam, or a pipe from one of the pumps may be used to compress the
air or vapour in the hydrocarbon reservoir so as to cause an equable flow
of the oil or hydrocarbon into the furnace chamber. To start the engine
after lighting the gas or oil or hydrocarbon a few strokes may be made
with the pistons both of the engine and pumps; by this means air for
combustion is forced into the furnace, and at the same time a vacuum
is formed in the steam chamber causing a circulation of the products of
combustion through the liquid in the boiler until sufficient pressure
exists to enable the engine to be self-acting. Link motions attached
to the piston rods of the pumps enable the supply of both air and fuel to
be regulated independently of each other, and the fire can be ex-
tinguished by simply turning off the supply of fuel and air.
The following are amongst the advantages of the construction before
described: Steam can be raised almost immediately upon lighting the
-

page_text: fire or turning on the gas. The temperature of the gaseous products of
combustion although very high are yet by the close contact which they
have in passing through the tubes with tlic water or other liquid in the
boiler enabled to absorb sufficient moisture to prevent the destruction to
which pistons and cylinders are liable when the products of combustion
are used directly from the furnace without passing through water, on
the other hand the steam is sufficiently superheated. The air and fuel
may be both heated if desired by the waste or rejected heat of the steam;
after leaving the cylinders of the engine water is supplied in the usual
way to the boiler.