IMPROVEMENTS IN MARINE ENGINES
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Henry Glaysher at the Office of
the Commissioners of Patents, with his Petition, on the 16th April
1872.
I, HENRY GLAYSHER,, of Newport, in the Isle of Wight, Medina
Cement Works, Medina River, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN MARINE ENGINES," to be as follows:-
In marine engines constructed according to my Invention there are
three box or chest shaped stationary cylinders made with cross ribs
outside to ensure strength; they range by the side of each other and
are fixed to a foundation plate. The centre cylinder is intended to
work at a high or medium pressure while the two outside cylinders
work at a low pressure. Each is provided with pistons made with
three sets of segments having springs, two sets having parallel pieces
with mitre joints at the angles, and the middle set being made with
angular pieces for crossing the joints. There are two piston rods fixed
to each piston, which rods' work through two stuffing boxes on the
cylinder covers, and a cross head is fixed thereto, the centre of which
has two gudgeons for connecting the rods to the cranks. The ends of
the cross heads also work on the frame rods which serve as guides, the
whole forming a very strong and steady parallel motion.

page_text: I should here state that the centre cylinder only is supplied with
steam from the boiler, which exhausts itself back into a receiver fixed
in the steam chest of the boiler, from whence issue two steam pipes
which supply the two low-pressure cylinders with steam. The slides
are reversed by the ordinary link motion. The air pump works from
a direct motion at the back of the engine over a surface condenser.
In order to make the theory upon which my Invention is based
better understood, let it be supposed that a steam vessel is about to
start. It is now that the paddles and floats have sufficient time for
exerting their entire pressure on the water as it is comparatively still;
but when the vessel has attained its full speed the paddles begin to
lose their previous effect, because the water is passing the vessel so
rapidly that the floats cannot overtake it in time to render any further
effect. The paddles thus require greater speed to enable the floats to
overtake the passing water in order to urge the vessel still faster.
This object I propose to effect in the following manner:-The cranks
and paddle shafts of the low-pressure cylinders make three revolutions
while the crank of the high-pressure cylinder makes only two; this
method of working not only economises the steam and fuel but keeps
the paddles at a great speed from the exhaust steam of the high-
pressure cylinder. Again instead of having large low-pressure cylinders
as is usual for expansion in compound engines the extra speed allows
of their being made of a more uniform size and of smaller dimensions
and also prevents too much back pressure, and compared with the room
taken up by the vibration or oscillation of the cylinders of the ordinary
oscillating engines the three box-shaped cylinders previously mentioned
will represent an area of piston surface of nearly five to one in
comparison with two round cylinders of the same diameter in nearly the
L
same space.