IMPROVEMENTS IN ENGINES WORKED BY HEATED ATMOSPHERIC AIR
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
10th April 1875.-A communication from abroad by Robert
Holdorff and Wilhelm Bruckner, of the Firm of Holdorff and
Bruckner, of Vienna, Empire of Austria.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN ENGINES WORKED BY
HEATED ATMOSPHERIC AIR," a communication, to be as follows:-
According to these improvements I construct an engine with a furnace
hermetically closed, within which atmospheric air forced in by an air
pump is caused to expand, being thereupon conducted to the piston of a
single-acting cylinder.
The air pump and the working cylinder are in one piece, erected at
one side of the furnace. In a line with both is the fly wheel shaft, set
in motion by a beam oscillating below the furnace. A shaft for working
the valves is fitted between the cylinder and the furnace, and it is
rotated directly from the beam by means of a small connecting rod.

page_text: This shaft is connected with a governor by means of a pair of bevelled
wheels, in such wise that it can regulate the admission of the cold air
into the furnace.
The furnace is fitted to the upper part of the cast-iron framing. It
consists of a cylinder of iron plate of sufficient height to contain thio ash
pan and the fire-box, it is lined with fire-brick and fitted at the top
with a cover of the same material The space intermediate between the
cylinder of iron plate and the outer cylinder on the framing is used to
heat the fresh air as it is admitted. The ash pan and the fire-box space
are each fitted with air-tight doors, and both are also provided with
openings communicating with the space for initially heating the air;
thus may be termed the feed air heater. The heated air escapes from
the furnace at two branch pipes in the top of the fire-box space, which
unite where they open into the valve chest. The whole is closed by an
air-tight cover. Below this is a funnel-shaped vessel, into which the
fuel for the furnace is supplied during the working of the engine. The
remaining space between the furnace and the upper part of the casing is
filled up with slow conducting material.
The engine cylinder is held to the furnace by means of two flanged
hollow passages or conduits bolted thercon. The lower pipe serves to
conduct the cold air out of the bottom part of the cylinder into the feed
air heater, and thence into the furnace. Contained within the upper
passage are supply valves for regulating the admission of heated air into
the cylinder, and it is also connected with the conduit leading to the
smoke stack. The said engine piston is hollow, and extended from to its
bottom side is a hollow trunk of smaller diameter fitted to the connecting
rod for working the beam. The annular surface resulting from the
difference between the area of the piston and that of the trunk is used
as the piston area of the air pump. Thus annular surface is preferably
so proportioned relatively to the area of the top of the piston on which
the beated air acts that the pressure on both sides are equal or nearly so.
Both the main piston and the plunger thereon are preferably tightened
by means of leathern rings. The clack valves for the air pump are fitted
inside with small conical cylinders cast on the bottom part of the main
cylinder. The governor works in such wise that as the balls rise the
arms on which they are suspended press down a pin on the hollow
spindle, and thereby open a cylindrical slide valve within the passage for
the cold air. By this means a portion of the cold air from the air pump

page_text: may be allowed to escape, a corresponding reduction of pressure inside
the furnace being the result.
The said enginc in its entirety works as follows:-On the pistons
rising the lower part of the cylinder space gets filled with fresh air,
which enters through the suction valve at its bottom. On the descent
of the piston this air is forced through the outlet valve into the space
for initially warming the air. This air may, as required, enter either
below the fire-bars or direct into the fire-box, according as the respective
inlets thereto are opened or closed; it thence flows through the air valve
into the cylinder, impelling the piston downward, the bottom part of
the piston at the same time forces another portion of air into the furnace,
and so on.
Towards the end of the stroke the inlet valve for the air is
caused to shut, and the exhaust valve to open, letting the spent air
escape into the chimney. When the engine is standing both the hot-air
valves are kept open by suitable gear, whereby direct communication of
the furnace with the smoke stack is kept up. The doors at the sides of
the fire-box and ash box are used only while the engine is standing.
The fuel is first fed into the funnel at the top; the outer door is then
closed, and a conical valve covering the bottom of the funnel opened,
whereupon the funnel emptics itself of fuel upon the grate.
It will be evident that the relative positions of the furnace, the
cylinder, the governor, and the fly wheel can be varied without departing
from the essence of this Invention. The governor may in such case be
driven by belting acting by means of bell-crank levers and rods upon a
suitable valve, regulating the inlet of the cold air into the furnace.
•
The details of the gear for working the inlet and exhaust valves for
the hot air may be variously modified.