IMPROVEMENTS IN AUTOMATIC GOVERNORS FOR MARINE ENGINES
Year: 1879

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN AUTOMATIC GOVERNORS FOR MARINE ENGINES." A communication from
abroad by Charles William Cooper, of the City, County, and State of New
York, United States of America.
Sealed the 12th August 1879, and dated the 17th June 1879.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark at the
Office of the Commissioners of Patents on the 17th June 1879.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN AUTOMATIC GOVERNORS FOR MARINE ENGINES."
A communication from abroad by Charles William Cooper, of the City, County,
and State of New York, United States of America.
The object of this Invention is to provide means for automatically arresting or
retarding the rotation of a steam-ship propeller as soon as the propeller during the
pitching of the vessel is raised out of the water, and automatically to re-apply
steam and cause the propeller to operate as soon as the latter re-enters the water.
The Invention consists in providing means for governing the engine and its
action by the variation of the height of the water as compared with that of the
vessel at the place where the propeller is situated, so that in fact the shutting off of
the steam will be gradual and not sudden at any time. To this end I attach to the
throttle valve certain mechanism that extend to a chamber located near the stern
of the vessel in such manner that the weight of the water on a diaphragm in that
chamber will open the throttle valve, whereas the moment such weight is removed
or reduced the valve will be closed in corresponding degree.
Figure 1 of the accompanying Drawings is a longitudinal section of a propeller
steam-ship provided with the improved automatic governor; Figures 2, 3, 4, and 5
are longitudinal sections of modifications of the same.
Similar letters of reference indicate corresponding parts in all the Figures.
In Figure 1 is illustrated one form of the Invention.
A is a chamber, provided

page_text: with an elastic air and water tight diaphragm a, and located near the stern of the
vessel or the part where the propeller is situated. The diaphragm is supported by
a disc on the outside against pressure from within; or the chamber may be a
cylinder provided with a piston, or may be constructed in any way in which a
variation of pressure from within operates the mechanism hereinafter described.
By a tube b or otherwise the chamber A communicates with the water outside of
the vessel near the propeller; one or more of such tubes b may be provided. The
disc or piston a of the chamber A connects by rods e, levers, or chains with the
throttle valve for other governing valve of the engine in such manner that the
pressure on the disc or piston tends to open the valve and to hold it opened, but
such pressure is opposed by a spring g, or by a weight or other force, which in turn
tends to close the throttle valve.
The object is to shut off the steam more or less as the propeller gets wholly or
partly out of the water. As soon as in elevating the propeller, or as the water
recedes from the propeller, the height of the water near the propeller is lessened,
the pressure of the water in corresponding degree becomes less on the diaphragm a,
and thereby enables the spring g or its equivalent to move the throttle valve and
shut off the steam according to the height to which the propeller is raised out of
the water.
The spring g or its equivalent should be of such tension only that the pressure
on the diaphragm or piston shall suffice to rotain the valve fully open, or at least
as far open as may be desired (for which purpose a suitable stop could be supplied
to the throttle valve) until the propeller is about to appear at the surface, when the
pressure on the diaphragm becomes reduced sufficiently to allow a partial closing of
the valve by the spring.
It will be observed that if the water is to act directly upon the diaphragm or
piston, as just described, it will be necessary to place the chamber A near to the
bottom or lower part of the propeller, and in order that the pitching of the vessel
shall not materially change its lovel with respect to that of the propeller it must be
as near to the propeller as possible. In cases where such an arrangement is not
convenient I locate the governing chamber A close to the valvo f, as in Figure 2,
and instead of having the water press directly upon the diaphragm or piston a I
'use compressed air as a medium through which the pressure of the water at the
propeller is transmitted to the governor. This apparatus or modification is shown
in Figure 2. In this Figuro it is shown that the chamber A is near the throttle
valvo, and that it communicates by a tubo i through an opening in the stern of the
vessel with the water near the bottom of the propeller. The chamber A and tube i
constitute an air chamber.
By means of a small air pump; operated by the motion of the engine, or other-
wise, air is forced into the chamber A or pipe i at any desired point at a rate
sufficient to compensate for any wastage and for the contraction in the pipe when-
ever the pressure increases.
Surplus air when pumped into the chamber A will find its way out at the bottom
of the pipe through the water. The pressure of the water against the air in the
pipe holds it compressed to a greater or less degree, according to its height, and
transmits its power to the diaphragm or piston, determining thereby the consequent
opening of the throttle valve according to the height of tho water about the propeller.
By proper adjustment this valve can be made to close so that the engine may go as
fast or slow as may be desired, if the propeller is entirely or partly out of the water.
In other words the moment the pressure of the water at the lower end of the pipe i
is reduced the pressure of the compressed air upon the diaphragm is reduced in
corresponding degree, enabling the spring g to partly close the throttle valve; and
if the lower end of the pipe i is entirely out of the water there will be no effect
upon the diaphragm by anything contained in the chamber a, thus giving the spring g
or its equivalent full power to close the valve.
By having a chamber or an enlargement of the pipe at the bottom of sufficient

page_text: capacity to compensate for the contraction of the air when the pressure increases
constant pumping may not be necessary, and a hand pump worked occasionally
may be sufficient. This same arrangement would be properly operated if the
chamber A is placed near the stern part of the vessel.
Another modification is shown in Figure 3, and consists in the use of a per-
pendicular or pendant bar or block k, having a limited vertical movement, which
block or bar is suspended either in a sheath or covering near the stern of the vessel
in such manner that the sea water has free access to and around it. The sheath
may be omitted and the block or bar freely suspended into the water. In new
vessels a hollow metallic stern piece may be made to contain said block or bar. The
bar may be made of any suitable material, either of greater or less specific gravity
than that of the water, a metallic cylinder or pipe with the ends closed would be
very suitable. The length of the bar and the height at which it is placed should
about coincide with that of the diameter of the propeller, although it may project
far above if desired.
If the bar is so light that it tends to rise spontaneously when the level of the
water is at the top of the propeller a spring or weight should be supplied to it for
the purpose of holding it down. The top of the bark is connected by chains m,
rods, wires, or otherwise to the throttle valve, so that the weight of the bar tends
to close the valve; but a spring g or other equivalent device at the valve tends to
counteract the weight of the bar and to open the valve. The spring g or its
equivalent should be of such tension that it should keep the valve open or to the
required opening until the propeller is about to appear at the surface of the water,
when being less buoyed by the water the bar becomes heavy enough to overcomo
the spring g and a closing of the valve takes place, and a consequent reduction
of motion of the engine in proportion as the water leaves the propeller.
In Figure 4 I have illustrated still another modification, which consists in using
a bar or rod which may be made of such specific gravity that its buoyancy instead
of its weight shall be the force opposed to the spring at the valve. In other words,
if the bar , shown in Figure 4, is in the full depth of water it will be elevated to
open the valve, whereas if the propeller is raised out of the water the buoyancy is
reduced, allowing the spring g to close the valve. In such a case tho bar should
be made as light as possible, and a connection be made either at the bottom or the
top of the same in such manner that as the water leaves the propeller exposed and
the buoyancy of the piece becomes less the spring at the valve will suffice to close
it to the desired extent.
Figure 5 is another modification of the Invention, in which instead of placing the
chamber A near the bottom of the propeller I place it near to or above the top, but
carry the inlet pipo i so as to receive the water low down, as in Figure 1.
In this case when the water gets below the top of the propeller the water volume
outside becomes less than that in the chamber, thus causing a suction upon the
diaphragm or piston. This suction I employ to close the valve and oppose it by a
force that tends to open it.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as new and desire to secure by Letters
Patent is,―
First. The connection of the throttle or governing valve of a marine engine with
mechanism communicating with the water near the propeller for affecting tho
position of the throttle valve by the depth to which the propeller enters the water,
substantially as specified.
Second. The combination in a propeller steam-ship of the throttle or governing
valve with mechanism communicating with the water near the propeller, and
having the tendency to open the valve by the weight of the water in which the
propeller is contained, in combination with a spring g or equivalent device, which
counteracts said mechanism and tends to close the valve, or vice versa, substantially
s specified,

page_text: Third. The chamber A placed in communication with the sea water near the
propeller and with mechanism connected to the throttle valve, substantially as
specified.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Seventeenth day of June, in the year of our Lord
One thousand eight hundred and seventy nine.