Year: 1886

page_text: I WILHELM EIMECKE of the firm of Messrs Gebruder Eimecke of Braunschweig
in the Empire of Germany, Engineer do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :—
And in order that my invention may be better understood I have caused to be
appended hereunto one shoet of drawings marked with letters of reference to
which I will now refer.
Figs. 1, 2, 5, 6 & 12 are vertical cross sections, & Figs. 3, 4, 7, 8, 11, 13, 14 and 15,
sectional plans, and Fig. 10, a side elevation of my invention.
In carrying out my invention and referring to Fig. 1, I set into the furnace
concentrically, several annular jackets m, by means of which, hollow spaces are
formed containing stationary air bodies.
As a stationary air body column is a very bad conductor of heat, and a suitable
number of such air bodies may be employed consecutively, the heat given off gets
greatly reduced.
It will be found most practicable to form the inner body n out of fire-proof
material, and arrange around the same the other annular jackets m for the
formation of the intended hollow spaces. The latter may also be filled with non-
heat-conducting material, and that most practically, the first one with the very best
non-heat-conducting material even if expensive, and in the other spaces cheaper
and better heat conducting material.
Fig. 1 represents a furnace intended for coal fuel.
A furnace for gas, spirits, or petroleum, would have to be altered to suit
circumstances.
The fire pot B, with cooling jacket G, is on its inner or outer or on both
peripheries, provided with rib-like axial projections or hollow spaces, by means of
which a uniform passage of the working air body or hot gases, and an increase of
the heat or cooling surface, is obtained.
By means of the axially arranged projection E on the outside of the fire-pot B,
see Figs. 1 to 3, fluest of uniform section, all around the same are formed, through
which the hot air on its way to the chimney, passes, which ensures a uniform
passage of the hot air & thereby a uniform heating of the fire-pot surface.
This effect is increased by the distributing flange C provided with openings v, v.
The same purpose in effect, is produced by the rib-like projections or hollow
spaces arranged axially in the interior of the fire-pot, which in this case, see
Figs. 1-3, are formed by means of drilled holes 8 in which are bars r. By this.

page_text: construction exceedingly small, and in the sectional average, perfect uniform
hollow spaces are produced through which the working air body passes, which is
afterwards permitted to leave below, heated quite uniformly.
These bars are set at suitable distances apart, see Fig. 2, and are held in the
middle of each opening by means of suitable projections. Above these bars r,
Fig. 4, is situated the regenerator R which may be constructed in a similar manner
as described.
The same is shown in the drawing, see Fig. 4, as consisting of a cast iron
cylindrical jacket with ribs arranged axially.
To effect the same purpose the cooling jacket G, Figs. 1 & 5, is also constructed
in the same manner. The outer ribs serve for the increase of the cooling surface,
and the inner hollow spaces formed through the bars have for their purpose, the
production of exceedingly small, and as great surfaces, as possible, representing
passages whereby a quite uniform passage and cooling of the working air body is
obtained.
Figs. 6 to 8 show the fire-pot B made out of corrugated sheet metal, which
is particularly suitable for engines of small power. Fig. 8 shows the lower end of
the displacing piston x also of a corrugated section, so that in this case, it corre-
sponds just the same as when made of cast iron see Figs. 1-4, the sections of the
passages for the working air body, being produced as small as possible.
Below the displacing piston x, Fig. 1, a piston y provided with regenerator
pipes is arranged, Into the pipes z are telescoped other metal pipes which are
kept equal distances apart from each other by means of projections, see Fig. 9, in
order that a part of the air coming from the cooling jacket G, has to pass through
these pipes and will become heated by their large surface.
Underneath these pipes is placed a heating plate a over which passes the
already heated air, which thus get heated most intensely.
To regulate the air body in the engine (working cylinder) self actingly, that is
to say, to equilibrize an unfavourable vacuum or compression, which may be caused
through loss of air or on stoppage of the engine, by the air being drawn in; a
cut-off valve d, see Fig. 1, is employed at the working cylinder, by which communi-
cation can be effected either to the inside or outside. By regulating the pressure
of a spring, the cut-off arrangement can be suited and set exactly for the highest
or lowest pressure to be admitted. If these limits are overstepped in one or
another direction, the suction valve will open inwardly, or the back pressure valve
outwardly.
To regulate the pressure for the engine from its governor, the working cylinder
is provided with a cut off arrangement (cock e valve, etc) which is opened and
closed by the governor.
Behind this cut off arrangement is also arranged a valve box f, which opens
inwardly & outwardly. If the normal speed of the engine is overstepped in one or
the other direction, the cock e, or other suitable cut-off arrangement, is opened.
The air stream which is of more than atmospheric pressure, then leaves the
working cylinder, & will lift the back pressure valve of the valve box f, and
escape.
During the vacuum period the suction valve opens and the entering air stream
passes through the cock, c, etc, into the working cylinder in order to reduce the
number of revolutions of the engine.
The displacing piston x and the working piston W are in this construction
connected with the crank shaft M in the following manner.
In the two bearings K, Figs. 10 and 11, is mounted the forked balance lever F,
which on one side is connected to the crank shaft M by means of a connecting
rod, and on the other side by means of the double links u, u¹ with the working
piston W. On the rotating shaft U which passes through the balance lever F, is
keyed the forked lever see Fig. 11, which latter is connected with the double
guide rods and, by means of the cross head L, fixed to the piston rod of the
displacer x.

page_text: On the end of the rotating shaft U is mounted the crank lever S which latter is
connected by means of a guide rod, to the crank lever N, fixed on the crank
shaft M.
The lever N is about 150° to 180° in advance of the crank pin Q of the crank
shaft M.
that an
The lining out of the furnace A, in Fig. 12 is done in such a manner,
annular air chamber is formed, to prevent as much as possible, the escape of heat
to the exterior.
The cooling of the working air body takes place in the engine illustrated in
Fig. 12, in the usual manner, while the heating of the air is performed in the
following way. The fire pot B is inwardly provided with teeth, while the
regenerative heating cylinder C, which reaches nearly to the bottom is provided
with teeth outwardly, see Fig. 13. Into the inner teeth of the fire pot B, I fit
with a uniform play space, for the passage of the heating and working air body,
the outer regenerative heating cylinder C. As will be seen on Fig. 13, a great
heating surface is obtained by means of the teeth fitting into each other and
having a corresponding play space, through which the air is conducted, in
corresponding thin air bodies.
.
In the same manner the cooling of the working air may be effected, and the
teeth of the toothed surfaces may be of different shapes.
The teeth extent along the whole height of the inner cylindrical surface of the
fire pot B, Fig. 12, and along the same height of the regenerative heating cylinder C,
inserted into the fire pot, In order to obtain also a large heat receiving surface,
the fire pot B, Fig. 14, may also be provided outwardly with ribs or projections, or
the fire pot B, Fig. 14, may be provided with hollow ribs between which I insert the
regenerative heating cylinder C in such a manner as also to leave a corresponding
play space for the passing & becoming heated, air. The bollow small ribs of the
regenerative heating cylinder C in Fig. 14, may be substituted by inserting loosely,
flat iron, or other metal bars.
These arrangements have for their purpose, the production of spaces for the
passage of air becoming heated, which are everywhere uniform in width and very
narrow, whereby the largest heating surfaces possible are produced.
The teeth of the regenerative heating cylinder C, in Fig. 13, may also be sub-
stituted by bars, of iron or other metal, having the form of teeth and being loosely
inserted, but such loose inserted teeth must be provided with a few projecting pins,
by means of which the same lay themselves against the inner teeth, cast on the
fire pot B, in order that a corresponding space for the passage of the passing air is
formed.
The employment of flat iron bars, in Fig. 14, takes place in the same manner.
If the form of the lower part of the fire pot would be the same as in the hot air
engine of Stenberg, the inner cylindrical surface of the pot may be provided with
outer teeth, and the outer also, which get touched by the fire, with inner teeth;
the regenerative heating cylinder, which in this case would nearly reach to the
bottom of the annular space would then be provided with inner and outer teeth, or
the same may be arranged on both or more surfaces.
If the displacer D, Fig. 12, is ascending, the air coming in this case from above
out of the cold space, would pass below into the small space between the surface of
the displacer and cooling jacket surface, passing on below, until where the inner
portion of the regenerative heating cylinder surface C, becomes a little narrower in
diameter. In the latter place is moving with as little play as possible, and
consequently as tight as possible, but without friction, the lower end of the
displacer D.
Around & close underneath the flange E, of the regenerative heating cylinder C,
are drilled holes, as illustrated, through which the air from above passes, down-
wards between the surface of the fire pot provided with inner teeth and the
regenerative heating cylinder surface provided with outer teeth and becoming
heated in entering under & passing through the inner flange of the regenerative

page_text: heating cylinder into the heated space above the fire pot bottom, which course the
air on its return also takes when the displacer is descending. In Fig. 12, the
arrangement of the fire-pot B and the regenerative heating cylinder is as shown in
Fig. 13. From below the fire pot B, is slid over the regenerative heating cylinder C,
and fixed to the flange E of the regenerative heating cylinder, by means of screws.
The lower end of the regenerative heating cylinder C is inwardly provided, for
the purpose of strength, with the already named flange.
The fire pot B, fig. 12, is formed at a suitable height with the already described
drilled flange. Fig. 15 shows a modification of the fire pot B, or more particularly
the arrangement of ribs on the same. In this modification the ribs of the cylinder
surface are also continued on the bottom of the fire pot & finish in a ring the
height of the ribs.
The perforated flange C through which the hot gases are drawn to the chimney,
may also be arranged inclined instead of horizontally to the cylinder axis, and in
such a manner that the highest point is opposite the chimney pipe in order to
ensure on such place, as long ribs and heating surface as possible.
Having now particularly described and ascertained the nature of my said
invention & in what manner the same is to be performed I declare that what
I claim, is:-
In a closed hot air engine.
Ist The employment of annular jackets m set into the furnace concentrically, for
the purpose of the formation of hollow spaces, containing stationary bodies of air,
which may be filled up with bad heat conducting material.
Ilad The employment of axially arranged rib-like projections for the formation
of hollow spaces on the inner or outer or both surfaces of the fire-pot B. and
cooling jacket G for the combined purpose of effecting a uniform passage of the
working air body or hot gases & of increasing the heating & cooling surfaces.
IIIrd The combination of the regenerator pipes z. with the heating plate a
employed below the same for the purpose of intensely heating the air bodies by
passing them over the highly heated heating plate.
IIIIth The employment of an inwardly and outwardly communicating valve
arrangement & & f on the working cylinder for the purpose of a self-acting & from
the governor controlled, regulation of pressure of the working air body.
Vth The combination of the working & displacing piston with the crank
shaft M by means of the double links u & u³, connecting rods 7, the forked
balance lever F double lever P crank, levers S and N & connecting rods belonging
to the latter.
VIth Dispensing with the cooling arrangement, pipes & plate on the displacing
piston, & substituting therefore the arrangement of the fire pot named in Claim II,
consisting in the arrangement of inner teeth on the fire pot, in combination with
outer teeth on the regenerative heating cylinder for the purpose of producing great
heating surfaces & narrow passage of the air to be heated as shown in section in
Figs. 13 & 14.