IMPROVEMENTS IN MOTIVE-POWER ENGINES FOR PROPELLING VESSELS AND FOR OTHER PURPOSES
Year: 1876

page_text: "
PROVISIONAL SPECIFICATION left by the said Abraham Pope at the Office
of the Commissioners of Patents on the 22nd March 1876.
ABRAHAM POPE, of No. 190, Edgware Road, in the County of Middlesex.
IMPROVEMENTS IN MOTIVE-POWER ENGINES FOR PROPELLING VESSELS AND FOR
OTHER PURPOSES."
This Invention has for its object improvements in motive-power engines for
propelling vessels and for other purposes.
For propelling steam launches and other small vessels I pass steam from a boiler
to an injector, and cause it to draw water from the outside of the vessel and force
it as a powerful current through a turbine. The turbine. has a vertical axis which
by spur gear drives at a lower speed another vertical axis carrying two loose
bevelled pinions, and between them is a bevelled wheel which is fast upon the shaft
of the screw propeller.
In connection with the bevelled pinions are friction cone clutches by which
either pinion can be made fast with its axis. The clutches are actuated by a
reversing lever.
In piston engines actuated by steam or other clastic fluid I cause the valves to
be worked by fluid pressure in the following manner:-As the main piston
approaches the end of its stroke (in either direction, for the arrangements of the two
ends of the cylinder are similar) it passes a small port in the cylinder side, and
steam from behind the piston enters a cylindrical chamber which contains a secondary
piston. This piston when it moves carries the valve of the main cylinder with it.
The valve is an ordinary slide valve working over the usual ports; the piston which
works it is double, and the valve is situate between the two faces in a space which
serves as a steam chest. The steam passing from the main cylinder moves the
secondary piston until the slide valve lias moved from end to end of its course, and
then the secondary piston comes to rest without striking the end of the cylindrical
chamber in which it works; this is brought about by providing in the side of the
chamber a port, which as soon as it is uncovered permits the steam behind the
secondary piston to pass to the exhaust. There is also a small clack or piston valve
provided in the passage by which the steam passes from the main cylinder to work
the slide valve; it is lifted by the steam in passing through the passage, but as
soon as the slide valve commences to admit steam to cause the return of the main
piston, the steam, finding its way by a channel provided for the purpose, acts upon the
Price 211

page_text: top side of the clack valve and closes it, and the travel of the slide valve-is completed
by the expansion of the steam already behind the secondary piston. When the
clack or piston valve falls, at the same time that it closes the passage between the
main cylinder and the chamber in which the secondary piston works it opens a
passage between this chamber and the exhaust, so that there may be no back
pressure to obstruct the return of the secondary piston.
The arrangement may be modified by causing the clack or piston valve when it
lifts to open a communication between the exhaust and the chamber in which the
secondary piston works. In this case no steam is allowed to pass from the main
cylinder to act on the secondary piston; but this is perforated on both its faces, or
is not tightly fitted so that steam leaks past the faces, and the piston moves to the
end of the chamber which is open to the exhaust.