CERTAIN IMPROVEMENTS.IN..STEAM ENGINES
Year: 1856

page_text: application for. Letters Patent was not given within the time prescribed
by, the Act.).
י
PROVISIONAL SPECIFICATION left by Jaines Prescott Joule at the Office
of the Commissioners of Patents, with his Petition, on the 26th February
1856.
I, JAMES PRESCOTT JOULE, of Manchester, in the County, of Lancaster,
Fellow of the Royal Society, do hereby declare the nature of the said Inven-
tion-of "CERTAIN IMPROVEMENTS.IN..STEAM ENGINES," to be as follows:-
out.
My improvements relate to apparatus for condensing steam, as applied to
steam engines, as follows: The, steam, after performing its expansive action
on the piston of the steam cylinder, is conducted through a pipe or pipes,
surrounded with water or other refrigerating substance, as in the method
originally employed by Watt. The pipes are placed either in a vertical or
in an inclined position, the highest end being that at which the steam enters,
and the lower or lowest that at which the air and condensed water is pumped
The condensing pipes may be conveniently made of iron tubing, of one
or one and a half inches diameter, and should present about three square feet
of superficial surface per each horse power of the engine. If constructed of
copper, two square feet of surface will be sufficient for each horse power. The
water or other refrigerating substance is made to pass in a contrary direction
to the steam, as in the apparatus known by the name of "Liebig's Condenser."
Where water has to be pumped for the purpose of refrigeration, it is advisable
to have the means of regulating the velocity or stroke of the pump so as to

page_text: use no larger quantity than required. Where the engine is situated near a
stream of water, or where water service pipes are at hand, the use of a pump
may be dispensed with, as also in marine steam engines, where by the motion
of the vessel the sea water may be made to pass along the condensing pipes.
Where a large quantity of water cannot be obtained, the atmospheric air itself
will answer the purpose of a refrigerating substance by making the condensing
pipes of sufficient superficial area. A pump draws the air and condensed
water out of the condensing pipes, and forces the water only into the steam
boiler. This pump may be worked either directly by the bean of the engine,
in which case its cubical content need not be greater than one-hundredth of the
cubical content of the steam cylinder, or at a diminished velocity, as in the case
of the ordinary force pump of a small high pressure engine. The air is got rid
of by causing the condensed water and air in their way towards the boiler to pass
a part of the conveying tube or a receptacle in connexion therewith higher than
the adjacent part nearer the boiler. This receptacle for the air may be con-
veniently placed immediately over the upper clack of the pump. Wherever
'it is placed, all that is necessary for the discharge of the air as it accumulates
is to provide an orifice of sufficient dimensions to allow it to escape into the
atmosphere. For this purpose a loose screw, a small stop-cock, even a flaw in
the metal would answer the purpose required, which is to allow the air to escape
before it can enter the boiler, and thence pass again to the condensing tubes.
These improvements are applicable to all steam engines, of whatever size or
for whatever purpose intended.