IMPROVEMENTS IN CALORIC ENGINES
Year: 1875

page_text: Sealed the 7th. March 1876, and dated the 8th September 1875.
PROVISIONAL SPECIFICATION left by the said Oscar Stenberg at the
Office of the Commissioners of Patents, with his Petition, on the
8th September 1875.
I, OSCAR STENBERG, of Helsingfors, Finland, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN CALORIC ENGINES," to
be as follows:-
According to this Invention I make the cylinder of cast iron, and
form a back continuation thereof of thin sheet iron terminating in a cast.
iron inverted hollow closed head, which is exposed to the furnace heat.
The piston is hollow, and has a cup leather packing; movement is.
transmitted therefrom to the crank by connecting rod or rods. The
piston terminates behind in a shect-iron hollow closed head, which serves

page_text: as a cooling appliance or bad conductor of heat. Between this piston
head and the aforesaid closed cylinder head I place a freely working
partition, the central part of which consists of one or more layers of
bad conductors of heat, such as wood and ashes, and the front and back
continuations of which consist of sheet-metal ring jackets enclosing
respectively the cooling part of the piston and the cylinder head, but
with an air space between for the passage of cool air. The partition
-receives reciprocating movement from cam or eccentric on the crank
shaft by weigh shaft and connecting rod or otherwise, the stroke being
about 3, that of the piston being 2.
Machines constructed as aforesaid may be made double acting (thus
for some purposes, such as small vessels, dispensing with a fly whoel)
by adding another cup leather placed the reverse way, and by placing a
small suction valve on the piston, which valve opens automatically in
the moment that the piston has got quite to the end of the back
stroke.
The cylinder is cooled by the air which by the fire is drawn into a
fluc enclosing the cylinder. Part of the air passes into a heated state
to the furnace for supporting the combustion, thus causing economy of
fuel. In hot climates this flue or jacket may also be kept cool by means
of cold water.
The play or space between the cylinder and the moving partition
being only 1/8 inch for large or small engines it is obvious that it becomes
comparatively smaller for the larger ones, and that pressures of com-
pression and expansion (vacuum and expansion) also become greater for
the same.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, OSCAR 30
STENBERG, of Helsingfors, Finland, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of September, in the.

page_text: year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Oscar Stenberg, Her special
licence that I, the said Oscar Stenberg, my executors, administrators;
and assigns, or such others as I, the said Oscar Stenberg, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for " IMPROVEMENTS IN:
CALORIC ENGINES," upon the condition (amongst others) that I,. the said
Oscar Stenberg, my [executors or administrators, by an instrument. in
writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
!.
:
NOW KNOW YE, that I, the said Oscar Stenberg, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings
and to the letters of reference marked thereon, that is to say:-
1
·
This Invention will be best understood by reference to: the accom-
panying Drawings, of which Figure 1 is a vertical longitudinal section
of a caloric engine constructed according to this Invention; Figure 2, a
plan section through the centre of the cylinder; Figure 3, end view of
the cylinder with part of the framing in section; and Figure 4 is an
outside elevation of the engine to a smaller scale.
Figures 5 to 11 are diagrams explaining the action.
According to this Invention I make the cylinder a' of cast iron, and
form a back continuation a thereof of thin sheet iron terminating in a
cast-iron inverted hollow closed head b, which is exposed to the furnace
heat. The piston c is hollow, and has a cup leather packing; movement
is transmitted therefrom to the crank by connecting rod or rods d. The
piston c-terminates behind. in a sheet-iron hollow closed head fi.which

page_text: {
"
serves as a cooling appliance or bad conductor of heat. Between this
piston head and the aforesaid closed cylinder head I place a freely
working partition i, the central part of which consists of one or more
layers of bad conductors of heat, such as wood and ashes, and the front
and back continuations of which consist of sheet-metal ring jackets
enclosing respectively the cooling part of the piston and the cylinder
head b, but with an air space between for the passage of cool air. The
partition receives reciprocating movement from cam or eccentric on the
crank shaft in this case by a curved slot, levers p and m on a weigh
shaft n, and piston rod 7, or connecting-rod-or-otherwise, the stroke being
about 3, that of the piston c being 2. The rod 2 passes through the
centre of the piston c in this case; a roller on the fly wheel works
in the curved slot of the lever p, and this communicates motion
thereto.
The action of the engine is as follows:-Figure 5 shews the position
in which the movable partition iis, quite at the back; atmospheric air
can then enter into the cooling space. The engine moving in the
direction of the arrow the piston c goes back, but the partition i remains
standing, because the roller, works in the curved slot, the radius of which
is equal to the distance from the centre of the shaft e. By this return
of the working piston c the air in the cooling space will be compressed
until the position is arrived at shewn at Figure 6.
The next moment (as shewn at Figure 7) by a sudden quick advance of
the partition, the piston c remaining meanwhile almost stationary, the
compressed air goes into the fire-space, obtains a higher temperature and
elasticity, and drives the piston c forward. The roller q in the curved
slot goes back again, the partition i follows the piston c exactly, and so
that the cold air layer between both is always ½ inch, and thus a com-
plete expansion takes place until come to the position, Figure 9. When
come to this position the partition i begins its return stroke, equalizes
the pressure, and sucks fresh air in through the cup leather s, if by any
chance a loss should occur by leakage...

page_text: Engines constructed as aforesaid may be made double acting (thus for
some purposes, such as small vessels, dispensing with a fly wheel) by
adding another cup leather placed the reverse way, and by placing a
small suction valve on the piston, which valve opens automatically.
in the moment that the piston has got quite to the end of the back
stroke.
.:
Figure 11 shows an indicator diagram of such an engine by dark
cherry red hot head.
The action of such a double-acting engine is as follows:-Figure 6 is
now the starting position of the piston; as the valve opens at the end of
the return stroke of the piston there is atmospheric air in the cooling
space, which in the next moment, position Figure 7, arrives to the hot
space, and expands to the position shown at Figure 9; the movable
partition at that point commences its return stroke, equalizes the
pressure, and arrives into the position shown at Figure 5, where the
original quantity of air at atmospheric pressure must fill the now larger
cooling space, the piston c remaining in its forward position. The
pressure behind the piston c will thereby be lowered below the pressure
of the atmosphere, and the pressure of the outer air (the cup leather
being applied from without) will push the piston back till it comes into
the position at Figure 6; the engine then starts afresh, as described.
Several engines constructed as aforesaid have already been made; the
indicator diagrams shown are from an engine with 9 inch diameter and
5 inches stroke, English measure. The proportion of waste space to
the working quantity of air was consequently as 1 to 3, and is by larger
engines found to be much less. .
The cylinder is cooled by the air which by the fire is drawn into a
flue enclosing the cylinder; part of the air passes into a heated state to
the furnace for supporting the combustion, thus causing economy of
fuel. In hot climates this flue or jacket may also be kept cool by means
of cold water.
The play or space between the cylinder and the moving partition
being only '/th inch for large or small engines it is obvious that it becomes
comparatively smaller for the larger ones, and that pressures of com-
pression and expansion (vacuum and expansion) also become greater
for the same.

page_text: And having thus fully described the nature of this Invention I declare
that I claim, the construction and application of caloric engines with a
working piston c and movable partition i constructed and operating sub….
stantially as set forth.
In witness whereof, I, the said Oscar Stenberg, have hereunto.
set my hand and seal, this Twenty-eighth day of February, in the
year of our Lord One thousand eight hundred and seventy-
six.
stantially as set forth.
In witness whereof, I, the said Oscar Stenberg, have hereunto
set my hand and seal, this Twenty-eighth day of February, in the
year of our Lord One thousand eight hundred and seventy-
six.