IMPROVEMENTS IN HOT-AIR OR CALORIC ENGINES
Year: 1884

page_text: C
I, FRANCIS KNOEFERL, of 100 Bolsover Street, Portland Place, London, in the
County of Middlesex, Engineer do hereby declare the nature of said Invention
for "IMPROVEMENTS IN HOT-AIR OR CALORIC ENGINES" and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My Invention relates to hot air or caloric engines. In engines of this class as
heretofore constructed, the noise caused by the air entering and leaving the open
end of the cylinder has been very unpleasant, especially where the said engines
have been placed in work-rooms for driving sewing machines or the like.
The object of my Invention is to avoid this noise, and to this end it consists
essentially in arranging an independent working cylinder in combination with two
chambers within each of which works a displacer, one of the said chambers being
connected with the working cylinder on one side of the piston and the other
chamber on the opposite side. With this arrangement the same air is used
continuously thereby obviating the necessity for connecting the interior of the
cylinder with the atmosphere.
In the accompanying Drawing
Figure 1 is a sectional elevation of an engine constructed according to this
Invention, the displacer chambers being arranged vertically.
Figure 2 is a similar view showing the displacer chambers in an inclined
position.
Similar letters of reference indicate corresponding parts in both Figures.
Referring first to Figure 1. A indicates a metal casing containing two
chambers a a¹ which are preferably cylindrical, but which may be of any other
suitable shape. Within each chamber a displacer a* works in the ordinary manner.
At the bottom of each displacer I form a flange a' which enters a corresponding
recess a³ in the base of the cylinder. The said flanges tend to prevent the air from
passing too rapidly into the heating chamber, whereby the air is more effectually
heated.
On the top of the chambers a a¹ is arranged a standard c to which is pivotted a
ever done end of which is extended, as shown at d. To the said lever the rods e
of the displacers are connected which rods are provided with joints e¹. The end d¹
of the lever d is connected by a rod f to the crank f' of the crank shaft g of the
ngine. The said shaft is provided with a second crank g¹ to which the piston
od h of the working cylinder i is connected.

page_text: The cylinder 18 pivotted to a bracket projecting from he want which
a water jacket around the upper parts of the chambers a a¹. The said cylinder
therefore oscillates as the crank shaft rotates.
The upper end of the cylinder i is connected by a pipe 2, (which is either flexible
or suitably jointed,) to the chamber a and the lower end of the said cylinder is
connected by a pipe to the chamber a¹.
m m indicate gas burners or other suitable means for generating heat, and o o
legs for supporting the apparatus.
In cases where the engine is required to work for a considerable length of time
it will be necessary to provide suitable pipes for admitting cold water around the
cylinder to keep the latter cool.
The operation of the engine is as follows, that is to say :-
Assuming the parts to be in the position shown in the Drawing, the fly-wheel is
turned by hand until the displacer in the chamber a¹ is at the top of its stroke
and the piston is at the centre of its stroke. The air below the said displacer is
then heated and expands so that the air in the upper part of the chamber a' is
forced through the pipe into the space below the piston and exerts an upward
pressure upon the said piston. At the same time the displacer in the chamber a
being at the bottom of its stroke, the air in the upper part of the said chamber is
cooled and condensed and the pressure above the piston is thus diminished. The
said piston, therefore, rises and through its rod h and the crank gb rotates the
crank-shaft g. While the piston is thus acting, the displacer in the chamber a²
descends and the displacer in the chamber a ascends so that the air in the chamber a¹
is displaced from the lower or heated end to the upper or cool end thereof, whilst
the air in the chamber a is displaced from the upper or cool end of the said
chamber to the lower end thereof where it is heated or regenerated. Therefore,
after the momentum of the fly-wheel has caused the crank g' to pass its upper
dead centre, the expansion of the air in the chamber a and the condensation of the
air in the chamber a¹ will cause the piston to move downward.
It will thus be seen that the air within the engine is not changed, but is
alternately heated and expanded and cooled and condensed in each of the aforesaid
chambers, the cooling being effected in the ordinary manner. The lower end of
the displacer, by reason of its peculiar shape, retards the passage of the heated air
from the bottom to the top of the chamber a or a¹, the expansion of the air below
the displacer, therefore, assists in raising the same.
In the engine shown in Figure 2, the displacer-chambers a, a' are inclined
towards each other as shown and the cylinder i, instead of oscillating, is fixed.
With this arrangement, the lever d is dispensed with and the displacers are
connected directly to the cranks g² g³ of the shaft g. Also the piston-rod h, instead
of being connected directly with the crank shaft, has a connecting rod .
this arrangement guides a are placed at the bottoms of the displacer chambers to
prevent the displacers from bearing against the sides of the said chambers.
With
The operation of this engine is substantially the same as that of the engine first
described.
By disconnecting one displacer from the oscillating lever in the case of the engine
shown in Figure 1, and from the crank shaft in the engine shown in Figure 2, and
also disconnecting the pipe between the corresponding chamber and the working
cylinder, the engine may be used as a single-cylinder engine. This is very
advantageous in cases where only a small amount of power is required.
I sometimes arrange in the tubes connecting the displacer chambers and working
cylinder, throttle-valves for preventing the too rapid exchange of air. The said
throttle valves may be operated simultaneously by any suitable governor.
Having now particulary described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is:-
First. In a hot air or caloric engine, the combination with a working cylinder,
of two displacer-chambers, one of which is connected with the upper part of

page_text: the said cylinder, and the other with the lower part thereof for the purpose
specified.
Second. The hot air or caloric engine constructed substantially as described with
reference to Figure 1 of the accompanying Drawing, and the modification thereof
as described with reference to Figure 2.