IMPROVEMENTS IN THE MEANS AND APPARATUS FOR CONTROLLING THE SPEED OF STEAM ENGINES
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Frederick William Durham at the
Office of the Commissioners of Patents on the 9th March 1881.
FREDERICK WILLIAM DURHAM, of Station Road, New Barnet, in the County of
Herts. "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR CONTROLLING THE
SPEED OF STEAM ENGINES."
In the Specification to Davies' Patent, No. 1846, of 1857, and others, it was
proposed to control the speed of marine steam engines by providing a chamber or
air vessel at the stern of the ship communicating at bottom by an opening in the
ship's side with the sea, and at top by a pipe with a cylinder or vessel having a
flexible diaphragm or piston connected to a lever actuating the steam supply valve,
so that assuming the air vessel to be partly filled with water, then on the stern of
the ship rising (thereby raising the propeller more or less out of the water), the
height of the water in the air vessel decreasing would cause the air in the same
and in the diaphragm-vessel to become more or less rarefied, and the consequent
decrease of pressure would cause the diaphragm to be depressed by the external
atmosphere or by a spring, and thus the closing of the steam supply valve to the
engine would be effected.
Such arrangements have the great disadvantage that one or more holes have to
be made in the side of the ship for establishing the communication betwen the air
vessel and the sea, so that if the connection with the air vessel should become
broken or leaky the sea would enter the ship through such hole. According to
one part of my present Invention I obviate this defect by means of the following
arrangement: I provide in the stern of the ship a tank containing water.
connected by a pipe to an air vessel situated nearer the ship's engine, which air
vessel also communicates by a pipe with a cylinder or vessel having a diaphragm
or piston connected to the lever of the steam supply valve in a similar manner to
the above described arrangement; thus, on the rising of the ship's stern, the tank
being raised in a corresponding manner relatively to the air vessel, water will flow
from the former into the latter to an extent corresponding to the increased head,
and the consequent increased compression of the air in the air vessel and diaphragm
vessel will cause the diaphragm to operate the steam supply valve so as to cut off
the steam supply more or less. On the stern of the ship sinking again the reverse
action will take place; thus the same mode of governing the steam supply as above

page_text: described is obtained without any hole being formed in the side of the ship for
the purpose.
In some cases the air vessel may be dispensed with and the tank be connected
directly by a pipe with the diaphragm vessel.
According to another part of my Invention I make use of the same action as
above described, namely, causing the raising or lowering of a column of water to
act upon a diaphragm or piston connected to the steam supply valve so as to effect
the opening or closing thereof for assisting the action of steam engine governors
of any known construction in moving heavy steam supply valves; for this
purpose a small tank, vessel, or tube containing water or other liquid connected in
a similar manner to that above described to a vessel with diaphragm or piston
actuating the steam valve is suspended or supported, so that it can be easily moved
up and down, for which purpose I prefer to counter balance the tank or vessel in
any convenient manner. This vessel is connected by gearing or levers to that part
of the governor which is moved on an increase or decrease of the engine's speed
occurring, so that, for instance, on an increase of speed taking place, the tank or
vessel will be raised by the motion of the governor, and by the increased pressure
thus produced in the diaphragm vessel by the increase of head of water the steam
valve will be more or less closed, while on the tank being lowered again by the
governor on a decrease of speed taking place, the valve will be opened again; thus
it will be seen that by the comparatively small power of the governor a
comparatively large balanced body of liquid can be raised or lowered so as to act
with comparatively great power on the diaphragm.