IMPROVEMENTS IN AIR, GAS, AND VAPOUR ENGINES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Echlin Molyneux, at the Office
of the Commissioners of Patents, with his Petition, on the 25th March
1862.
I, ECHLIN MOLYNEUX, junior, of Seaview, Enniskerry, in the County of
Wicklow, Ireland, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN AIR, GAS, AND VAPOUR ENGINES," to be as follows:-
The Invention consists partly in a novel method of alternately heating and
cooling air, gas, or vapour confined in an air-tight vessel or vessels, and
employing the resulting differences of elastic force due to these differences of
temperature to produce motive power. The engine which the Inventor pro-
poses to use consists partly of two air-tight vessels, tubular in form, for confining
the air, gas, or vapour to be alternately heated and cooled, the apparatus
for producing the alternations of heat and cold; and the working cylinder, with
its piston, by which the power generated is utilized.. The generating vessels
are similar in every respect; each contains at one end a reservoir of metal,
maintained in a state of fusion by a suitable furnace, and at the other a
reservoir of water. A combination of metallic surfaces, so arranged that air
can only traverse it in minute streams, (such as coil of wire, wire gauze,) and
which the Inventor calls the generator, occupies a part of the interior of each
generating vessel, and admits of being moved freely therein from end to end
by a rod passing through a stuffing box at one extremity. One extremity of
the generator when in motion, is heated by immersion in fused metal on

page_text: 'arriving at the bot end of the generating vessel, and the other is cooled by
contact with cold water on the completion of return stroke; but the inter-
mediate part is subject to neither of these extremes of temperature. To
prevent heat passing by conduction from the hot part of the generator to the
intermediate, and from the intermediate to the cold, they are separated by the
interposition of rings of any material which is a bad conductor of heat. The
generator acts in the following manner:-When it cominences to move toward
the cold end of the generating vessel the contained air has its minimum
temperature; as the generator makes its stroke it presents a succession of
metallic surfaces, each of a higher temperature than the preceding to the air,
which will necessarily become heated. When the motion of the generator is
reversed the air has attained its maximum temperature, and as during this
stroke the coldest parts of the generator are last presented the air will be
cooled. The intermediate part of the generator, which is neither brought in
contact with the fused metal or the cold water, serves to prevent the radiation.
of heat from the hot end of the generator and generating heat to the cold
by absorbing the emanating rays, and to economise the heat taken from the
air in the operation of cooling by presenting to it a succession of metallic
surfaces, each colder than the preceding, which retain the great part of the
heat, and restore it by a reverse process during the return stroke of the
generator to the air which is being heated. The Inventor converts the dif-
ferences of elastic force of the air confined in the generating vessel (obtained
by heating and cooling it alternately in the manner previously described) into
motive power through the medium of a piston working air-tight in a cylinder,
each compartment of which has a generating vessel attached to and in free
communication with it by causing the temperature, and consequently the
pressure of the air in one generating vessel, to be alternately greater and less
than in the other, a reciprocating motion of the piston is produced. Of course
it is necessary that at the same point of the thermometric scale the air in each
generating vessel shall have the same elastic force.
Recapitulation. Firstly, the Inventor claims the improved method of
causing the metallic surfaces employed to impart heat to the air to travel
through it, instead of as in all preceding air engines, forcing the air to travel
over the heated metallic surfaces. The advantages of the Inventor's method
are, that the air is more rapidly, completely, and economically heated, the
heating apparatus less complicated and costly, and the use of a forcing pump
to put the air in motion dispensed with.
Secondly, the Inventor claims the method of instantaneously restoring heat
to the metallic surfaces used for the purpose of raising the temperature of the

page_text: air by bringing ing them into contact with fused metal contained in the gene-
rating vessel.
Thirdly, the Inventor claims the arrangement of generator as described, by
which a great economy in the expenditure of heat is obtained.
The Inventor claims the following modification of the engine described
above:-The generating vessel may be cylindrical in form, and the generator
revolve on a spindle passing through the axis of the cylinder; the reservoirs
of melted metal and water being so placed that the generator is brought into
alternate contact with each of them at each semi-revolution of the spindle..
The communications between the working cylinder and the generating vessel
may be placed either above or below the water line in the cold water
reservoir; if placed above the water line, the piston is driven by cold air; if
below, the cylinder is filled with water, and the piston is driven by the
pressure of the air on the surface of the water in the reservoir.
The Inventor sometimes makes no provision for depriving the water in the
water reservoir of the heat which it receives from the generator, and the
engine is then driven by superheating the steam thus produced. In all other
respects the arrangement and working of this engine is exactly similar to
that already described, except that a safety valve, which can open only when
the vapour has its minimum temperature, is provided to prevent the pressure
coming excessive.