IMPROVEMENTS IN STEAM ENGINES, AND BOILERS
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Esau Rowing at the Office of
the Commissioners of Patents, with his Petition, on the 15th April
1864.
I, ESAU ROWING, of Norwich, in the County of Norfolk, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN STEAM
ENGINES, AND BOILERS," to be as follows:-
In carrying out this Invention I employ a double piston valve, the two
pistons being mounted on one valve rod, and the steam admitted between them,
so as to act equally upon both. Each piston valve works in a cylindrical
casing, in which opposite to each induction port of the cylinder is an annular
recess, so that a very slight motion of the piston valve uncovers a sufficient
area to admit steam to the whole cylinder at once. The valve rod is jointed
to a link having a pin at the other end, working in a slot in a lever capable
of vibrating on a fixed centre. The connecting rod from the excentric is also
provided with a pin working in the same slot, so that the motion of the
excentric is communicated through the connecting rod, slotted lever, and link
to the double piston valve. The "governor" of the engine is placed over the
excentric rod, and the sliding boss of the former is connected to the latter by a
link or links, so that as the balls of the "governor " expand the excentric rod
is raised, causing its pin to rise in the slot of the lever, and communicate a
decreased motion to the piston valve, and vice versâ, and by this means a
variable expansion motion is obtained. I make the piston hollow, and nearly
half the length of the steam cylinder, and I place the exhaust port midway
in the cylinder, so that the piston itself acts as the exhaust valve, opening and

page_text: closing the exhaust port as it passes the centre of the cylinder. I construct the
boiler of three longitudinal tubes placed at a convenient distance apart in the
same horizontal plane, and connected together by a series of smaller transverse
tubes. There are also two other longitudinal tubes placed between the above,
for superheating the steam after it leaves the other tubes, and before it pro-
ceeds to the cylinder. A series of small tubes projects downwards from each
of the main tubes in a vertical direction along the whole length of the latter.
These vertical tubes are provided with inner tubes so as to separate the
currents of steam and water. The sides of the fire-place immediately outside
the vertical tubes, and the top of the same above the transverse tubes
throughout the whole length of the boiler, are enclosed by fire-brick walls
and ceiling or otherwise, and outside the same is an air space, by means
of which air is admitted from the smoke box end of the boiler, and absorbing
the heat radiated from the fire-brick passes in a heated state, to an enclosed
ash-pit beneath the furnace. Arranged longitudinally below the boiler is a
feed-water tank, kept at a constant level by means of a pump, and into this
tank, above the surface of the water, the exhaust steam from the cylinder
passes, thus heating the feed-water before its admission to the boiler. The
working parts of the engine are fixed on the top plate, which supports the
longitudinal tubes of the boiler.
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