IMPROVED MEANS FOR RENDERING MARINE GOVERNORS MORE EFFECTIVE
Year: 1876

page_text: LETTERS PATENT to John Mackenzie, of Blyth, in the County of Northumber-
land, Engineer, for the Invention of "IMPROVED MEANS FOR RENDERING MARINE
GOVERNORS MORE EFFECTIVE."
aled the 28th March 1877, and dated the 6th October 1876.
PROVISIONAL SPECIFICATION left by the said John Mackenzie at the Office
of the Commissioners of Patents on the 6th October 1876.
JOHN MACKENZIE, of Blyth, in the County of Northumberland, Engineer. "Iм-
PROVED MEANS FOR RENDERING MARINE GOVERNORS MORE EFFECTIVE.'
The governors attached to marine engines have hitherto been found deficient in
their ability to regulate the speed of the engine with promptitude and certainty.
This imperfection is due to the exhaust side of the piston or pistons exerting a force
which continues after the supply of steam to the cylinder or cylinders has been
reduced or shut off. This shows that the forces acting upon the piston or pistons
are not all under the controlling power of the governor attached to the engine,
consequently the action of the governor is not at once communicated to the engine
and the speed thereof expeditiously regulated. To remedy this evil is the object of
my Invention, for which purpose I fit or place a valve, slide, sluice or cock, or other
similar contrivance in the exhaust passage or eduction pipe of the engine. This
valve, slide, sluice, or cock may be attached by rods and bell cranks to the throttle
valve of the steam pipe, or it may be connected directly to the governor and worked
thereby in conjunction with the throttle valve. The parts are so arranged that the
valve, slide, sluice, or cock shall open or close in unison with the throttle valve.
From the foregoing it will be observed that directly the steam passage is enlarged
or reduced in area so in like manner is the exhaust passage, consequently the engine
receives at once the full benefit of the action of the governor and is not influenced
by the exhaust.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said John Mackenzie in the Great Seal Patent Office on the 6th April 1877.
JOHN MACKENZIE, of Blyth, in the County of Northumberland, Engineer.
PROVED MEANS FOR RENDERING MARINE GOVERNORS MORE EFFECTIVE."
"IM-
The governors attached to marine engines, and to those especially of the com-
pound class, have hitherto generally been found deficient in their ability to regulate
the speed of the engine with promptitude and certainty. This imperfection is due
in most cases to the exhaust side of the low pressure piston receiving from the
condenser a propelling force, due to the vacuum therein, and which continues after
the supply of steam to the high pressure cylinder has been reduced or cut off. This
shows that the forces acting upon the pistons in the high and low pressure cylinders
are not all under the controlling power of the governor attached to the engine,
consequently the action of the governor is not speedily communicated to the engine
and the racing thereof expeditiously regulated.
Many devices have been designed and contrivances applied to remedy this evil,
but hitherto they have been found either defective, useless, or to produce such
deleterious results as to endanger thereby the stability of the engine. To obviate
these objections without entailing a more dangerous feature in the working of the
engine, is the aim of my Invention, which I purpose to carry out in the following
manner:-
In the exhaust passage or eduction pipe of the engine to be provided with my
Invention I fit a valve of a special form, to be herein-after described. The spindle
of this valve may be worked by rods and suitable levers from and in accordance
with the throttle valve of the steam pipe, or it may be worked directly from the
governor in conjunction and in unison with the said throttle valve.
The most suitable form of valve for the purpose of my Invention is a circular or
elliptical disc having a spindle passing through and projecting from opposite points
of the periphery, and forming the axle on which the valve works. The said spindle
is not diametrical, but passes through the disc rather on one side of the centre;
thus the valve is divided into two unequal sides or flaps, and consequently not in
equilibrium. When fitted in the exhaust pipe this valve should be so placed that
the action of the exhaust or condenser upon the larger flap, being in excess of that
exerted upon the smaller flap, shall always tend to open it. Indeed, it is essential
to the successful carrying out of my Invention that this valve should never com-
pletely close the exhaust pipe, which would occasion by concussion an undue strain
to act upon other parts of the engine and air pump. The means I adopt to insure
the proper working of this valve will be herein-after fully explained.
Although I profer the above-mentioned valve to be of the form and construction
above described, as being not only efficient but also economical, yet the same results
would follow if the said valve were made with equal sides or flaps, the equilibrium
of the same being destroyed by a suitable spring or by the following means,
namely-drilling a hole or holes through or bending back that flap which is not
to receive upon it the full power from the condenser. An equilibrium valve without
any one of these devices would occasion by concussion damaging effects upon the
low-pressure cylinder, and likewise overload the air pump.
I will now proceed to explain my Invention more fully by aid of the accompany-
ing Drawing, reference being had to the letters and figures marked thereon.
Figure 1 is a plan, partly in section, of a compound marine engine provided with
my improved means for rendering marine governors more effective. Figure 2 is an
elevation, partly in section, of the same on line A, B, (Figure 1,) and Figures 3, 4,
4x, 5, 6, 7, 8, 9, and 10, various details (drawn to a larger scale) to be herein-after
specified.

page_text: In Figures 1 and 2, C, D, are respectively the high and low pressure cylinders
supplied in the usual manner with steam from the steam pipe S, 8* being the
spindle of the throttle valve (herein-after described as the "steam valve "), the handle
or lever of which is suitably attached to a rod F which is in communication with
any approved governor for regulating the supply of steam to the engine. To this
rod is linked by a hinged joint f¹ the rod F* connected by a bent arm or lever G
and suitable attachments to the spindle rod H, by which latter a special valve K
(herein-after described as the "exhaust valve ") is worked in the exhaust or eduction
pipe E leading to the condenser. The bent arin or lever G is keyed on the spindle
rod H and provided with a curved slot i (see Figure 3) for the purpose of regulating
the travel of the exhaust valve in relation to that of the steam valve, for upon this
in a great measure depends the successful working of the Invention, it being
distinctly understood that the former valve should never entirely close the exhaust
pipe; consequently, the latter valve must, when closing or partly closing, perform
its journey in the time that the exhaust valve completes say seven-eighth only of a
similar distance. This eventuality is obtained to any desired degree by suitably
placing and fixing the sliding block i* (Figures 4 and 4*) (which forms the means
of attachment between the rod Fx and the bent arm G, see Figures 1 and 2) in the
curved slot i (Figures 2 and 3); thus, should the said block when in position
coincide with the point marked Í in Figure 3, the exhaust valve would then perform
its duty at a slower rate of speed than that performed by the steam valve; con-
sequently when the latter becomes shut, the former continues partly open. By
raising or lowering the sliding block (the rod F* being hinged at f1 for that purpose,
see Figures 1 and 2) the area of this aperture may be increased or diminished at
will.
The curve of the slot in the bent arm or lever G, Figures 2 and 3, is described
from the hinged joint f1 (Figure 2), by which means the initial position of the
exhaust valve is unalterable while its final position may be varied to any extent in
a manner already explained to suit the working conditions. Figure 4 is a side
view, and Figure 4* a plan of the sliding block, or it may be of any approved
construction, and secured in the said slot and the rod Fx attached thereto by means
BO well understood as to require no further description.
The exhaust valve might be made of a less diameter than the exhaust pipe; this
would ensure the non-closing of the exhaust pipe. I prefer, however, as being more
efficacious, the arrangement above described, which also permits the area of the
aperture remaining in the exhaust pipe at the closing of the steam valve being
regulated according to circumstances by the engineer.
Figure 5 shows a plan, and Figure 6 an elevation, of the exhaust valve K
(Figures 1 and 2). It is so fitted in the exhaust pipe E that the action of the
condenser upon the said valve when partly closed shall, by reason of the larger
flap being then in the position shewn in Figure 6, always tend to reopen it and
thereby assist the governor, through the rods H and Fx (Figure 1), in putting steam
on again. The presence and duly working of this valve in the exhaust pipe prevents
the condenser exerting in opposition to the governor any perceptible propelling
power upon the exhaust side of the low pressure piston, and for reasons before
explained produces no pernicious effects upon the governor, engine, or air pump.
Figures 7 and 8 are plans, and Figures 9 and 10 side views of modified forms of
the exhaust valve, which from the Drawing and foregoing description are so readily
understood as to require no further explanation.
I am aware that a slide, sluice, or cock fitted in the exhaust pipe and worked as
above directed may produce moderately good results, but they are each liable when
the speed of the engine is reduced to load the governor and thus retard the action
of the same and delay the engine's accession to power.
Having now set forth the nature and object of my said Invention, together with
the manner of carrying the same into effect, I wish it to be understood that I claim
as my Invention secured to me by the above in part recited Letters Patent the

page_text: method and means above described and illustrated on the accompanying Drawing
of rendering marine governors more effective.
In witness whereof, I, the said John Mackenzie, have hereunto set my hand
and seal, this Fourth day of April, in the year of our Lord One thousand
eight hundred and seventy-seven.
JOHN MACKENZIE. (LS.)