IMPROVE- MENTS IN AIR ENGINES
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Michael Henry at the Office
of the Commissioners of Patents, with his Petition, on the 23rd June
1864. A communication from abroad by Louis Dominique Girard, of
33, Boulevart Saint Martin, Paris, France.
I, MICHAEL HENRY, of 84, Fleet Street, in the City of London, Patent
Agent, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN AIR ENGINES," communicated to me from abroad by Louis Dominique
Girard, of 33, Boulevart Saint Martin, Paris, France, to be as follows:-
In this engine, while the air is being heated after having been compressed, its
volume remains unaltered, so that an increased pressure is obtained beyond that
of the compressed cold air. The temperature may be partially or wholely recon-
stituted during expansion. Part of the heat carried off with the escaping air
is regenerated by a set of tubes and flat metal plates, and a portion of the air
not deprived of heat supplies the furnace. There is a force and pressure
pump and a double receiver composed of two heads or cylindrical portions, in
which work two displacing pistons on one rod; the receivers, which may be cast
with the pump, temporarily accumulate compressed air; the whole charge
compressed by the compressing piston is received within them, such air being
at rest till displaced by the piston; such movement is effected by a fresh volume
of air, which tends to become compressed at the other side of the compressing
piston, and moves the second displacing piston, thus displacing the first
measure of compressed air. A double slide valve is worked by the driving
piston without cams. The regenerators are placed on each side, that is, one

page_text: in
before the mouth of each receiver; the air passes through them twice, once
taking up heat and next parting with it before escaping. There are two
heaters corresponding with the receivers and regenerators for heating the air,
which when displaced passes into the regenerator and takes up an initial
position at the other side of the displacing piston, which it leaves immediately
after; each heater, receiver, and regenerator does its work separately. There
is a working or motive cylinder and piston, with appendages for transmitting
the power applied on each side of the piston. When the furnaces have been
lighted and the engine started the air in the compressing cylinder will move
the first piston, and the second piston will displace the air in the corresponding
receiver, which will pass through the valve opening and into the regenerator
in a cool state, and thence into the heater, where it will be heated and increase
pressure, but not in volume, and will take its initial position at the other
side of the displacing piston, whereupon air will pass again into the heater,
become heated, and work the working or motor piston, at the same time the
crank having overcome its dead point will make its first throw. The pressure
becomes reduced as the air expands and the piston continues its stroke, the
air not being compressed first; it will be otherwise after the first throw, the
other side acting in like manner, but with air which, though not compressed
to the full pressure on account of the initial position of the compressing
piston, has power enough to keep the engine at work. The expanded hot air
after working the piston will escape into the regenerator, part with some of its
heat, and thence flow into the furnace. The hot air which did not pass into
the cylinder, but remained in the receiver after expanding, will flow through
the heater into the regenerator. At each stroke of the feed piston the dis-
placing pistons drive compressed air through the regenerators and heaters into
the receiver on the other side of the displacing piston, while the motor or
working piston completes and recommences its stroke; immediately afterwards
the hot air passes into a heater, expands, resumes its temperature, and acts on
the piston during its stroke. The heaters may be heated by a furnace under
a dome, and the air in them may be forced through narrow diametrically
opposite passages, so that to escape it must pass all round the dome. The
regenerators may contain a number of thin metal plates. For the piston
packing weak springs may be used, the packing being applied or rested
against the cylinder; between each round face of the segments is a little fluid
under the variable pressure acting on the pistons; the segments may be grooved
on the outer side and some play left between the flat sides of the segments
and the supporting surfaces, so that the fluid may press on the projecting
surface of the segments and pass into the small space between segments and

page_text: piston; there may be several segmental rings. An improved bearing is used
consisting of two boxes or shells excentric on their outer circumference and
resting on blocks of corresponding shape, so that when screwed together at
their larger ends the bearings describe an angle and bring their hollows near
together, i.e., the portions most exposed to wear are brought closest. An
improved clutch box for reversing the shaft is used when driving screw pro-
pellers, whereby the shock is reduced. In or in combination with one or
both portions of the clutch box is a double or extra clutch piece, collar, box,
or friction piece for exerting friction on the former till the vis inertiæ be
expended. The friction surfaces may be two annular conical pieces fitting into
each other and brought together by a nut. Portions of elastic packing ring
being introduced between the adjacent parts, a coating may be inserted
between the rubbing surfaces. The extra clutch box or friction piece has two
sets of teeth to gear into the driving or transmitting teeth; springs are fitted
to the clutches to control them as they come into gear, and thus prevent
liability to fracture from too sudden an engagement of the teeth.