Year: 1886

page_text: I, FRANCISCUS HENDRICUS EIJDMAN of Dordrecht in the Kingdom of Holland,
Engineer do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement :—
This invention relates to improved apparatus for governing the speed of steam
engines so as to prevent "racing" when the screw propeller, is raised out of the
water.
When a steamer runs on an even keel, no matter how much she may Poll on her
longitudinal axis, the screw propeller always remains submerged to the same extent,
so that the pressure of the water thereon does not vary materially, and consequently
the speed of the engine does not vary. If on the other hand the vessel pitches, or
the waves run in the direction of its length, the screw will be more or less
uncovered at intervals, requiring that the speed of the engine should be controlled
at those times in order to prevent "racing."
· The governors or controlling apparatus for steamers used up to the present time,
are so little suited for the purpose, that as a rule they are not employed, and the
steam supply to the engines is varied by hand when the vessel pitches.
The main disadvantage of existing governors consists in their spasmodic action,
in either suddenly cutting off the steam supply entirely or admitting the full;
supply, without effecting any gradual adjustment of the supply in proportion to
the extent to which the propeller is uncovered..
My present invention relates to automatic governing apparatus that acts quite
independently of the motion of the engine, and that regulates the speed of the
latter by the action of physical laws dependent upon the pitching motion of the
vessel, and in proportion to the extent to which the propeller is uncovered.
The apparatus will be readily understood on reference to the accompanying
drawings, in which Fig. 1 shews a part longitudinal section of a screw steamer,
with my invention applied thereto, and Figs. 2 and 3 show two different arrange-
ments of the apparatus to a larger scale.
A is a vessel situated at the stern of the ship and communicating by a pipe a
with a cylinder B aituated. in the engine room. The cylinder B contains a piston,
not shewn, which is connected by a rod b with a valve apparatus D for controlling
וווו..

page_text: the steam supply to the engine. The connection between the piston and this
apparatus may either be direct, as at Fig. 2, or indirect as at Fig. 3; in both cases
however a device F is applied for lengthening or shortening the distance between
the piston and valve or slide D. The latter is applied at a point between the steam
engine and the cut-off valve, as shewn at Fig. 1.
The regulating apparatus is actuated by means of hydrostatic pressure exerted
by any suitable liquid upon the piston: According to well known physical laws
this pressure is determined by the product of the sectional area of the piston
multiplied with the height of the column of liquid and its specific gravity. The
liquid employed may be oil, water, neutral salt solutions not affecting the metal of
the apparatus, glycerine, mercury &°. The greater the specific gravity of the liquid,
the smaller can be the diameter of the pipe and cylinder. I will assume the vessel A
to be partially filled with liquid while the pipe a and the cylinder B, up to the
underside of the piston, are entirely filled therewith, the liquid level in A being so
much above its level in B that the pressure exerted on the underside of the piston
is sufficient to support the weight of the latter and its appendages, and to overcome
the friction thereof. When the ship remains on an even keel the apparatus in this
condition constitutes a balance in equilibrio, but on the pitching of the ship, the
raising of A and sinking of B, or vice versa, will cause an increase or decrease of
the head of liquid in A, producing a rising or falling of the piston and a consequent
reduction or increase of the inlet area of the steam supply pipe, thus reducing or
increasing the steam supply to the engine, to a corresponding extent.
If the proportion between the pressure of the water on the area of the screw
blades, and the steam pressure that drives the screw were constant, that is to say,
if for example when the screw projected half out of the water, the regulating valve
were exactly half closed, while the engine made the same number of strokes as
when the screw was entirely immersed, then, as both the screw and the steam pipe
form circular planes, on any further rising of the screw out of the water a further
closing of the steam pipe in exactly the same proportion would be sufficient to
maintain the speed of the engine constant under all circumstances.
As however this cannot always be the case, it is expedient to form the aperture
of the steam pipe that is closed by the slide, or the slide itself, as a parallel trapeze,
the one converging side of which is formed with a determined curvature, which is
calculated from the work performed by the engines in its various phases. The
width of the pipe corresponds to the sectional area of the piston, the stroke of which
depends on the stroke of the slide and the manner in which the motion is trans-
mitted from the former to the latter.
According as the depth to which the ship is immersed varies, the angle of its
inclination at which the screw will become uncovered will also vary. In con-
sequence hereof the slide would, without some special provision, cut off the steam
either too soon or too late under certain circumstances. To prevent this, the slide
rod b may either be so constructed that it can be lengthened or shortened in
proportion to the degree of immersion, or the necessary adjustment may be effected
by increasing or decreasing the load on the piston. The most suitable would be, to
apply both these means, the coarser adjustment being effected by attaching more
or less of the weights E to the piston rod, while the finer adjustment is effected by
turning a screwed nut F on the two separate parts of the piston rod b, provided
with right and left handed screw threads.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. The use for automatically controlling the speed of marine engines, of apparatus
consisting of a vessel A, situated at the stern of the ship and partly filled with
mercury or other liquid, communicating by a pipe a with a cylinder B, situated in
the engine room, and having a piston which on the pitching of the ship is raised or
lowered by the increase or decrease of liquid pressure in the cylinder, and is thus
#1

page_text: made to more or less open or close the steam supply valve or slide, the adjustment
of the valve or slide according to the greater or less immersion of the ship being
effected by varying either the load on the piston or the length of the connection
between piston and valve or slide, substantially as herein described.
2. In apparatus such as is referred to in the preceding claim, constructing the
opening of the regulating valve or slide through which steam is admitted, or the
valve or slide itself of parallel trapeze, shape, the one converging side of which is
formed with a curvature that is calculated from the work performed by the engines
to which the apparatus is to be applied substantially as herein.described.
1
1
1000
ABEL & IMRAY,
Agents for the Applicant.