IMPROVEMENTS IN MARINE ENGINES
Year: 1883

page_text: LETTERS PATENT to James Hargreaves of Widnes in the County of
Lancaster Chemist for an Invention of "IMPROVEMENTS IN MARINE
ENGINES"
PROVISIONAL SPECIFICATION left by the said James Hargreaves at the
Office of the Commissioners of Patents on the 30th October 1883.
JAMES HARGREAVES of Widnes in the County of Lancaster, Chemist, "IMPROVE.
MENTS IN MARINE ENGINES
"
In order to obtain on board ship easily reversed propeller engines with the parts
in more compact form and to dispense with long shafts I use a prime mover, say a
steam caloric, gas or thermo-dynamic engine, to force water or other fluid at high
pressure into an air or other suitable accumulator. The said water or other fluid
is afterwards employed to actuate a reversible hydraulic motor coupled or geared
to the propeller or its shaft.
My invention is not confined to any particular form of prime mover or pump to
force the water into the accumulator, nor any particular class of accumulator, or
hydraulic motor as these may be greatly varied; the scope of my invention extends
to any prime mover operating a pump and also an accumulator and a hydraulic
engine adapted to impart motion to the propeller.

page_text: Fig 1 is a view showing part of a ship in outline and also the positions, arrange-
ment, and connections between the pumps operated by the prime mover, the
accumulator, the hydraulic motor and the propeller and shaft. Fig 2 is an end
view of the hydraulic motor.
A prime mover say a steam caloric gas or thermo dynamic engine is coupled to the
plunger, pumps a which force water oil or other liquid at a pressure of about
50 to 70 atmospheres through the pipe b into the accumulator cand thence to the
top compartment of the valve box d. The accumulator ĉ acts by the compression
of air and is provided with a small pumpe whereby the said accumulator is kept
charged with air as it escapes or is absorbed and carried away by the water oil or
other liquid, is an air vessel on the pipe b near to the valve box d to act as a
cushion and relieve the parts of strain due to the varying motion of the water oil
or other liquid through b. From the valve box the water passes through the
cylinders of the motor g which is here shown with three cylinders of the reversible
Oscillating type. Froin the said cylinders the water passes again through the lower
compartment of the valvo box to the pipe h and thence past the air vessel i and
vacuum chamber to the pumps a. The piston or plunger rods of the cylinders g
are connected direct to cranks on the propeller shaft k. propeller. m lever for
operating valve in box d for the purposo of starting reversing and stopping the
motor.
There is sufficient water oil or other suitable liquid put in the accumulators to fill
one of them about quarter full, and in the event of the hydraulic engine being stopped
the prime mover forces the whole of the water into the pressure accumulator, and
then draws out nearly all the remaining air from the vacuum chamber.
this is done. the prime mover begins to move more rapidly, but this is checked
automatically by an ordinary governor.
When
It will be obvious that the various parts may be of any usual construction
suitable for the purposes required and that the relative positions of the parts may
be altered, the distance between the propeller and the motor and the motor and the
pumps being varied to suit circumstances.
Amongst the advantages derived from my invention are: The power of the
hydraulic motor is given out close to the propeller instead of being conveyed
through a long shaft, the prime mover can be placed in any convenient position

page_text: without reference to the propeller; and the pipes for conveying power from the
prime mover to the motor may be carried along the bottom or sides of the ship or
in any convenient position away from the cargo space; the velocities of of the prime
mover and the propeller are not required to be the same, as is the case where the
prime mover drives the propeller directly. The relative velocities are dependent
upon the dimensions of the force pumps, and of the working pistons of the
bydraulic cylinders, which may be varied as circumstances require.
Having now described and illustrated the said invention in such manner that
others will be enabled to carry the same into effect I claim :-
The improvements in marine engines substantially as herein described and
setforth.
In Witness Whereof I the said James Hargreaves have hereunto set my hand
and seal this twenty eighth day of April in the year of Our Lord one thousand
eight hundred and eighty four.
J. JOHNSON
Patent Office
4 Clayton Sqr
Lpool
Witness
JAMES HARGREAVES. (L.S.)