IMPROVEMENTS IN HOT-AIR ENGINES
Year: 1879

page_text: LETTERS PATENT to Gilbert Lewis, of Moss Side, Manchester, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN HOT-AIR
ENGINES." A communication from abroad by Hugo Wippermann, of Essen
on the Rhine, in the Empire of Germany.
Sealed the 11th July 1879, and dated the 25th January 1879.
PROVISIONAL SPECIFICATION left by the said Gilbert Lewis at the Office of
the Commissioners of Patents on the 25th January 1879.
GILBERT LEWIS, of Moss Side, Manchester, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN HOT-AIR ENGINES." [A communication from abroad by Hugo
Wippermann, of Essen on the Rhine, in the Empire of Germany.]
The Invention relates to the class of hot air engines having circulating or
transferring pistons, which alternately transfer the air from the beating to the
cooling, and from the cooling to the heating parts of the apparatus. Previously to
the said Invention reciprocating pistons have been employed for this purpose.
According to the said Invention pistons or bodies revolving around axes are
employed in lieu of the said reciprocating pistons. In each case the body revolves
within a cylindrical chamber around an axis, which occupies the axial line of the
chamber or thereabouts, and the said chamber is heated on one side and cooled on
the other. The said body in what is considered to be the most suitable forın
consists of a semi cylinder, which may or may not be hollow for sake of lightness.
One part of the circumference of the said chamber, say, the lower part, is heated,"
and the opposite part is cooled by means of water or by other suitable means..
When the said body, is below the axis the charge of air. is exposed to the cooling.
effect, and when the said body moves into position above the axis, the said charge
is transferred into the lower half of the chamber and is exposed to the heating.
effect. The heated air is admitted to act upon the working piston of the engine.
When used as a pumping engine the water may be delivered into a casing enclosing
the upper part of the chamber. In single acting engines the said body is balanced

page_text: by means of a weighted fly-wheel or by other suitable means, and as the said body
is a revolving weight it acts in assistance of the fly-wheel if properly balanced. In
double acting engines the two bodies are placed on opposite sides of the axis so as
to balance each other, and in such a case the ordinary fly-wheel-may-be-dispensed
with. The circumferences of the said chamber and revolving body may be plain,
_or_if_it_is_considered to be desirable to increase the heat conducting surfaces the
said circumferences may be fluted, or be provided with gills, or be otherwise-formed
as.considered to be most suitable. The sides of the said parts may also be fluted,
-or-be-provided-with-gills,-or_be_otherwise formed to increase the heat conducting
surfaces
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Gilbert Lewis in the Great Seal Patent Office on the 25th July
1879.
'
GILBERT LEWIS, of Moss Side, Manchester, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN HOT-AIR ENGINES." [A communication from abroad by Hugo
Wippermann, of Essen on the Rhine, in the Empire of Germany.]
The Invention relates to the class of hot-air engines having circulating or
transferring pistons, which alternately transfer the air from the heating to, the
cooling, and from the cooling to the heating parts of the apparatus..., Previously to
the said Invention reciprocating pistons, have been employed for this purpose.
According to the said Invention pistons or bodies revolving around axes are
employed in lieu of the said reciprocating pistons. In each case the body revolves
within a chamber around an axis which occupies the axial line of the chamber
or thereabouts, and the said chamber is heated-on-one side and-cooled on-the-
other. In single acting engines the said body is balanced by means of a weighted
fly-wheel or by other suitable means, and as the said body is a revolving weight it
acts in assistance of the fly-wheel if properly balanced. In. double acting engines
the two bodies are placed on opposite sides of the axis so as to balance each
other, and in such a case the ordinary fly-wheel may be dispensed with.
In order that the said Invention may be fully understood, I have attached
hereunto a Sheet of Drawings made to a scale of about three inches to the foot,
and marked with letters of reference, to which Drawings reference will be made in
the following description of the Invention. In the said Drawings Fig. 1 represents
a vertical section, and Fig. 2 a plan of a single-sliding hot air engine constructed
in accordance with the said Invention. In the said Figs. A is the chamber;
the heating furnace, and C is the cylinder. In the example, the chamber A is
made of a globular form, and is formed by bolting or securing together two parts
a and a¹. The part a forms the crown of the furnace. The part a¹ is cast or
B is

page_text: formed with an outer shell, and water is caused to circulate in the space between
the inner and outer shells. The effect of this arrangement is that the lower part of
the chamber is heated by the fire in the furnace, and the upper part is cooled by
the water in the said space; a shaft d passes through the chamber a and occupies a
central position therein. The said shaft is fitted to revolve in bearings which are
formed with glands or stuffing boxes in order to prevent the passage of air through
the bearings, and in the example are screwed into the walls or shells of the upper
part a' of the chamber. Upon the said shaft is fixed a hollow body E. One half
of the said body is in the form of a hemi-sphere which is so formed and pro-
portioned as to clear the interior surface of the chamber A when the said body is
revolved therein, and at the same time to closely approach the said surface as
indicated in the Drawings. The other half e is so formed as that a space f exists
between the said body and the inner surface of the chamber. The said space
contains a volume of air, and it will be seen that at each revolution of the body E
the said air is exposed alternately to the lower heated part of the chamber, and the
upper cooled part of the same. In the example, an annular shell extends a short
distance over the part e of the said body, but the said shell may be dispensed with
if not considered to be necessary. Upon one end of the shaft d is fixed a crank
disc f¹ in which is fixed a crank-pin, which is connected by means of a link g with
a piston h which is fitted to slide to and fro within the cylinder C, which is open at
the end which is the lower end in the example. Upon the other end of the shaft d
is fixed a fly-wheel I, which is formed or fitted to balance the body E supposing
that the part e is not sufficiently heavy to balance the part marked E. The
upper end of the cylinder C is connected by means of a passage k with the upper
part of the chamber A. The said cylinder is provided with an inlet valve / which
opens to admit air whenever the pressure within the chamber or cylinder falls
below the atmospheric pressure. A suitable cock is applied at m in order that the
passage may be closed when desirable, as for example, when a pressure of air
within the chamber is to be obtained prior to the starting of the engine. The
piston h is packed in any suitable manner and by suitable means, in order that it
may slide within the cylinder in a suitably air-tight manner.
In the example
a tube n attached to the piston slides in a gland formed in the cylinder cover.
Lubricants can be introduced through the said tube to the upper connecting link
joint, but the use of the said tube may be dispensed with. In the example, the
parts are so proportioned as that the cubical contents of the space f shall be about
equal to the cubical displacement of the stroke of the piston, but these proportions
may be varied, being made such as are found to give the most satisfactory results.
The action of the engine may be described as follows:-A fire is lit within the
furnace B and water is supplied to the water space in the upper part of A. It is
considered that the best results are obtained by obtaining an initial pressure of
about fifteen pounds and upwards above the atmospheric pressure within the
chamber A before starting the engine. This may be effected by turning the shaft d
by means of the fly wheel, so that air is drawn in at l at one part of the stroke,
and is forced into the chamber A at another part of the stroke.
The pressure
produced by one stroke may be maintained until another stroke has been or is
being effected by closing the cock m. The volume of air within the space f
becomes heated by contact with the crown a of the furnace, and the pressure of the
air is thereby increased. The air expanded by the absorption of heat presses upon
the piston, and thereby effects the rotation of the crank-shaft. This rotation of the
crank-shaft moves the space f towards the upper and cooler part of the chamber, so
that when the piston is making its up stroke the cooling and as a consequence the
contraction of the air in the said space causes air to return from the cylinder to the
chamber. It will be seen that the continued rotation of the body E will cause a
flow of air alternately to and from the cylinder, and will thereby effect. the rotation
of the crank-shaft; I have selected a globular form of chamber as being the form.
of chamber considered at the time to be the most suitable, but the form of
chamber and of the revolving body may be greatly varied without departing from

page_text: the nature and intent of the Invention, as for example, the said chamber may be of
a cylindrical form, or of a double vee, or of an elliptical form in section on the
plane of the crank shaft axis, or of any other suitable sectional form on the said
plane, and if it be considered to be desirable to increase the heat conducting
surfaces, the inner surface of the chamber and the outer surface of the revolving
body may be fluted, or be provided with gills, or be otherwise formed as considered
to be most suitable. In cases wherein the engine is employed to actuate a pump,
the water raised may be caused to flow through the water space indicated-in-the-
Drawings. When arranged as a double-acting engine two chambers are provided
and the revolving bodies are fixed on opposite sides of the crank-shaft in order that
-they may balance each other, in which case the ordinary fly-wheel may or may
not be dispensed with.
Having now fully set forth and indicated the nature of the said Invention and
means whereby the same may be carried into effect, I would have it to be under-
stood that I claim,
First. The hot-air engine constructed. and acting substantially as set forth and
indicated herein before, and in and by the accompanying Drawings.
And, Secondly. The employment of bodies fixed to shafts and revolving within
chambers, substantially as and for the purpose set forth and indicated.
..In witness whereof, I, the said Gilbert Lewis, have hereunto set my hand and
seal, this Twentythird day of July, in the year of our Lord One thousand
eight hundred and seventy nine.
Signed and sealed by the
said Gilbert Lewis in
the presence of
EDWARD K. DUTTON,
Agent to the Patentee,
St. Ann's Churchyard,
Manchester.
GILBERT LEWIS.
(L.S.)