To all whom it my concern:
Be it know that I, John Ericsson, of the city, county, and State of
New York, have invented certain new and useful improvements in Air-Engines;
and I do hereby declare that the following is a full, clear and exact description
of the same, reference being had to the accompanying drawings, making a
part of this specification.
My invention consists in so constructing, arranging, and actuating the
supply and working pistons within a single cylinder, that the cold supply
air in being transferred to the heater for the purpose of having its tension
augmented, shall cool that portion of the cylinder in which the working
piston moves and keep it at so low a temperature that any kind of metal
or any other suitable material, such as leather, may be employed for rendering
the piston air-tight. In order to effect this, I connect the working and
supply pistons to the crank of a flywheel shaft by a system of levers,
rockshafts and connecting rods of such a nature that an alternating accelerated
and retarded reciprocating movement will be imparted to the two pistons,
capable of effecting the desired transfer of the air and cooling of the
working cylinder and at the same time to produce motive power.
My invention also consists in conveying the supply air from the cold
end of the cylinder to the opposite end by such means that every particle
of the air to heated is made to traverse the entire length of the heater;
all of which will be shown by the following description, reference being
had to the drawing, which represents a longitudinal section of an air-engine
with a single cylinder.
To enable others to apply my invention to use, I will proceed to describe
its construction and operation.
A, is an open working cylinder.
a, is a working piston.
a', is an airtight leather packing secured to the piston
by means of a follower.
a'', a'', is the piston-rod, composed of
a broad flat bar kept in a parallel position by a guide-piece b.
c, is the supply piston made hollow with a concave head
c'. This piston is elongated toward the heater, the elongation
forming an open cylinder as shown at c'', c''; the hollow
part between the two heads c and c' is to be
filled with pounded charcoal or other non-conducting substance. The circumference
of the supply piston c is notched all around as shown at
c''', the notches resembling the spaces between the cogs
of a spur wheel. The supply piston is also provided with a metallic packing
ring c4, which fits the bore of the working cylinder
and forms an airtight joint when pressed against the back face of the supply
piston-head during the inward motion of the supply piston. During the outward
motion of the piston, the ring is permitted to move back against the cheek
pins c5, a communication being thereby established
which allows the air to pass freely through the notches and behind the
packing ring toward the heater.
d, is the piston-rod of the supply piston, made to pass
through a stuffing box d' in the main piston and held in
parallel position by the guide piece b.
e, is the heater, consisting of an open cylinder with
a spherical head c'', the open end being secured to the flange
of the working cylinder or to its prolongation as shown at e'.
The said open end of the heater is provided with a brick front e''',
and firedoor e4.
f, is the fireplace; f', the grate; f'',
brick lining placed a short distance from the heater to allow the heat
after leaving the fireplace to act properly on the inside of the heater.
f''' is the ashpit, and f4 the
flue for carrying off the products of combustion. In engines of small power,
I carry this flue directly to the chimney; but in engines of greater power,
I first pass the products of combustion through the annular space formed
between the working cylinder or its prolongation and a surrounding jacket
composed of some non-conducting substance.
g, is a cylindrical casing, open at both ends, resembling
a telescopic tube large enough to allow the supply piston to work freely
within. This tube is secured to the inside of the working cylinder or its
prolongation by small socket bolts passing through the space between the
cylinder and the tube, or by other methods that do not interfere with the
free passage of the air through this space.
A' is a cavity formed on the inside of the working cylinder
or its prolongation for conveying the air readily from every part of the
circumference to the exhaust valve h. This valve is to be
actuated by suitable valve gear connected to the fly-wheel shaft in such
a manner that the valve will open when the supply piston has performed
the outward stroke, and close somewhat in advance of the completion of
the inward stroke of that piston.
i, is the inlet valve inserted in the main piston, guided
by the stem i', and held against the valve seat by a spring
or balance weight.
K, is the rockshaft extending across the cylinder, terminating
a short distance behind it and supported at each end by pillow blocks secured
to the flange of the open end of the working cylinder or otherwise supported
by appropriate side frames.
k', is a lever attached to said rockshaft for moving
the supply piston by means of friction rollers k'', and a
crosshead d''.
k''' is another lever, also attached to said rockshaft,
outside of the cylinder.
l, is another rockshaft extending across the cylinder
and supported by pillow blocks as before stated.
l', is a lever attached to rockshaft l,
for transmitting the motive power of the working piston. The upper end
of this lever is inserted into the main piston rod, appropriate bearing
brasses being applied in the rod for receiving the thrust of the lever.
l'' is another lever also attached to the rockshaft l,
close by the side of the lever k'''.
m, is the fly-wheel shaft; m', the crank
attached thereto, connected to the levers k''', and l'',
by means of connecting rods n, and o.
It will be evident on examining the drawing and the relative position
and movement of the crank, connecting rods and levers described, that the
two pistons will complete the outward stroke nearly at the same time; and
that during the inward stroke, the supply piston not only performs a much
longer movement than the working piston, but also that the former completes
its movement before the latter. It has been stated that the exhaust valve
h opens at the termination of the outward stroke of the supply
piston. It will therefore be seen that as this piston moves away from the
working piston during the inward movement, fresh cold air will be drawn
in through the self-acting valve i, filling the space formed
between the two pistons; at the same time the heated air behind the supply
piston will pass off through the exhaust valve h. It will
further be seen that during the outward motion of the supply piston, its
packing ring will be drawn back and thereby allow the air to pass through
the notches c''', from the cold to the hot end of the cylinder.
Further examination of the crank and lever movement will show that when
the working piston has performed a very small portion of the outward stroke,
the supply piston is far advanced, and that it soon overtakes the former
and moves with it to the end of the stroke. The cold air drawn in and confined
between the two pistons during their inward movement will consequently
be transferred to the space between the heater and supply piston. The pressure
produced by the increase of temperature during this transfer will propel
the working piston through the outward stroke and thus supply motive force.
The return stroke is effected by various means, such as
What I claim as my invention, and desire to secure by Letters-Patent, is:
HENRY T. BROWN,
WM. TUSCH.