AN IMPROVED HOT-AIR ENGINE
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Thomas Tertius Chellingworth
at the Office of the Commissioners of Patents, with his Petition,
on the 9th July 1870.
I, THOMAS TERTIUS CHELLINGWORTH, of 8, Great Queen Street,
Westminster, in the County of Middlesex, Civil and Mechanical
Engineer, do hereby declare the nature of the said Invention for "AN
IMPROVED HOT-AIR ENGINE," to be as follows:-
This Invention relates to various improvements in the construction of
and arrangement of hot-air engines.
My first improvement relates to the position and construction of the
working cylinders, which are placed at the end of the furnace furthest
from the fire-door, these cylinders are fitted with hollow pistons with
connecting rods driving two cranks placed in opposite directions. The
valves are placed on the sides of the cylinders furthest from the furnace
and a passage is cast round the side of the cylinder bottom connecting
them with the furnace, the length of this passage being sufficient to

page_text: protect the valves from the action of flame. In the back plate of the
furnace is a valve made to close with a lever and screw. When the fire
is lighted and is burning previous to the engine being started the heat
and flame from the furnace passes through the said valve, and under and
around the cylinder bottom, causing them to become heated, so that
on the starting of the engine the air from the furnace will pass into
cylinders, the bottoms of which are already at a high temperature,
preventing the cooling and contraction of the hot air, which would
otherwise occur if it passed into cold cylinders.
The second part of my Invention relates to the construction and
arrangement of air pump and furnace. The air pump is made double-
acting and bolted to the frame or side of the smoke box which contain
the cylinder bottoms, and is driven by a connecting rod attached to a
face plate or crank on end of the crank shaft. The furnace is constructed
of cast and wrought iron, the bottom being a cast-iron plate, which also
forms the bed plate for the whole of the engine; the back is fitted with
a flue valve before described, and the front plate is fitted with fire and
ash-pit doors, the whole of the doors and valves being made to fit air-
tight; the top of the furnace is arched and the sides and top are of
wrought iron bolted or rivetted to flanges on front plate, back plate, and
base plate; on the top of the furnace is a feed hopper for supplying the
furnace with fuel; the furnace is lined with fire-brick with openings at
back for the flue valve and passages leading to the working valves; at a
short distance from the back plate is a bridge built of solid fire-bricks
for some distance above the fire-bars, the remaining portion being built
of perforated bricks; the air is admitted to the furnace from the air
pump by a pipe in which is the throttle valve and also a valve for
directing the air either under or above the fire; the air passage under-
neath the fire is through the bridge and the passage above the fire are
on the sides of the furnace in the fire-brick lining, the bottoms of these
passages being connected with a tube or passage cast in the bed plate
and the top ends terminating in perforated fire-brick openings.
My third part of my Invention consists in the construction of the
governor, the pendulums of which are cast larger at the bottom ends
and tapering towards the joints, and at the top end are small levers
working between broad collars on spindle, this spindle is made to pass
down the upright shaft and is made to raise and lower a lever connected

page_text: with throttle valve; on the rocking shaft of the governor is a lever with
shifting weight for adjustment.
The fourth part of my Invention consists in the arrangement of cams
and levers, the cams being keyed on the crank shaft depressing levers,
the opposite ends of which are connected to the valves by slings and are
caused to return to their seats by steel springs.