Improvements in the Regulation of the Admission of Steam to Engine Cylinders.
Year: 1898

page_text: Date of Application, 7th Sept., 1898
Complete Specification Left, 6th June, 1899-Accepted, 29th July, 1899
PROVISIONAL SPECIFICATION.
Improvements in the Regulation of the Admission of Steam to
Engine Cylinders.
I, ALEXANDER BASIL WILSON, of Holywood, in the County of Down, Ireland,
Engineer, do hereby declare the nature of this invention to be as follows:―
The object of my invention is the attainment of practically uniform speed in
steam engines irrespective of power produced thereby or moderate variations in
steam pressure by the regulation of the quantity of steam admitted to each end of
each cylinder.
This invention applies more particularly to single-acting engines with
rotating admission and exhaust valves.
In this invention the amount of steam admitted into each end of each cylinder
and which is equivalent to the portion of stroke of the piston during which the
space swept through thereby is open to the source of supply of steam, and which
is hereinafter called the cut-off."
A long portion of the stroke being called a long cut-off, and a short portion an
early cut-off. Is regulated by the action of a centrifugal governor revolving at a
definite ratio to the speed of the engine in the well-known manner, the motion
due to the change in radial distance of the centre of gravity of the balls from the
centre of revolution arising from variations in speed, being made use of to
regulate the cut-off.
Whereas, in my Provisional Specification No. 10160/98 the speed of the engine
is regulated by a governor working within the steam chest and throttling the
admission of steam to the cylinder or cylinders, and whereas by such throttling
a less complete use is made of the energy of the steam passing through the
steam engine at varying powers, than if the cut-off be varied by the governor
according to the demand for power and the pressure of steam available.
Now in my invention. I place the governor which may be of the ordinary
gravity or spring operating type within the steam chest, and driven direct by a
rotating spindle, as described in Provisional Specification No. 10160/98 and I so
construct the balls of said governor that their motion is communicated to a ring
surrounding a portion of the steam valve, in which ports are cut, which ring
revolves at an equal rate with the rotating steam valve with similar ports, except
in so far as the motion of the governor balls, hereinafter called the balls, advances
or retards it with respect to the motion of the steam valve through a few
degrees of arc.
Outside and surrounding said ring, hereinafter called the live ring, I place a
second ring, hereinafter called the dead ring, in which ports are also cut, the
dead ring being so secured that it does not revolve with the steam valve, and live
ring.
The ports in these rings, and in that portion of the valve which is surrounded
by the live ring are so placed that when the balls are at their inmost position
with respect to the centre of the governor spindle by reason of the speed of the

page_text: engine being below the normal revolutions, the three ports, that is to say, the
port in the valve, in the live ring, and in the dead ring are opposite each other
at the moment of the full opening of steam admission to the cylinder, and when
the balls are furtherest out on account of the engine speed being above the
normal, the live ring is so far revolved round the valve and through a sufficient
arc to entirely close the aforesaid ports, or the opening from the steam chest into
the valve port, and at intermediate positions of the balls corresponding to different
speeds, the aforesaid opening is greater or less in proportion to such position.
The essential point of my invention consists in the use of a surface A, having
ports there-in and forming part of the rotating steam valve. A fixed surface C,
having ports there-in, opposite the ports in A, at the period of full admission of
steam to the cylinder. Situated between these two surfaces, the equivalent of a
plate B, having faces approximately steam tight to both A & B, surfaces, and with
ports cut there-in to correspond, which plate revolves with A, but is moveable by
the governor in the plane of its revolution, advancing or going back with
respect to A, in accordance with the inward or outward motion of the balls.
The surface A, corresponds and is part of the rotating steam valve. The plate B,
corresponds to the live ring, and the surface C, to the dead ring in the previous
paragraph.
At another part of the steam valve there is provided a port which corresponds
to an opening to the cylinder in the well-known manner, and having a similar
action in respect to the admission of steam to the cylinder as an ordinary slide
valve. This port in the steam valve is in addition to the aforesaid port, which can
be closed by the live ring, and which is hereinafter called port A. The port or
ports in the live ring are hereinafter called port B, and the port or ports in the
dead ring are hereinafter called port C.
In the admission of steam to the cylinder its commencement is determined by
the leading edge of the valve port uncovering the opening to the cylinder, which
period of commencement of admission is approximately at the beginning of the
stroke, and is in all cases so far as my invention is concerned, determined by the
position of such leading edge.
The period of cut-off in my invention is determined by the position of 'the
trailing edge of port B, closing the opening of port C. The extent of the cut-off
is determined by the position of the trailing edge of port B, which position is
regulated by the distance the balls are in or out in consequence of change of speed,
that is to say, when the balls are in and the engine running below normal speed,
the trailing edge of B, port closes C, port, at the same time as the main opening
into the cylinder is closed by the port corresponding thereto passing it, when.
however, the balls revolve at a greater distance from their centre of revolutions,
the plate B, is advanced in relation to the opening of steam port into cylinder and
its advance causes it to close port, C, more or less early in the stroke according
as the advance is greater or less.
Whereas, it is sometimes desirable that the speed of the engine can be reduced
for a short time below its regular working rate, I provide a means by which
the surface C, or the port C, or the dead ring, as hereinbefore mentioned, can be
moved through a few degrees of arc, against the direction of rotation of ports A
& B, so that the closing of the opening through ports B & C, may take place
earlier in the period of the revolution of the engine; the effect of such regulation
of the position of port C, which may be done by a screw or handle, or equivalent
means from the outside of the steam chest, being to entirely cut-off the admission
of steam to the cylinder when the governor balls are at less than their full out
position. As an example. With an engine arranged to run at the normal
speed of 400 revolutions per minute, with the governor balls at two-thirds of
their extreme distance from the centre of governor, and with the construction of
governor so arranged that the balls will go to their extreme distance with the
engine running at 408 revolutions, and that when the balls are at their

page_text: extreme distance the opening through ports B & C, is closed at the beginning of
the stroke, and that the governor balls when running at one-third their extreme
distance from the centre of rotation correspond to an engine speed of 392
revolutions per minute, and that with the balls at this position the opening
through ports B & C, is sufficient to fully supply the engine with steam, so that
the range of speed from 392 to 408 constitutes the working range of revolution
of the engine, and corresponds to the outer two-thirds of the position of
governor balls.
And if the governor be so arranged that at its inmost position the engine runs
at 384 revolutions per minute. If then the ring or port C, be advanced against
the direction of the rotation of the valve until the openings through ports B & C
are closed, when the balls are at two-thirds their distance from the centre of
rotation, corresponding to an engine speed of 400 revolutions, the range of
speed of the engine becomes reduced by such adjustment of port C, so that
400 revs. becomes its maximum speed, and 384 its minimum, its mean speed being
392, or 2% lower than its previous speed.
.
2003
Improvements in the Regulation of the Admission of Steam to
Engine Cylinders.
I, ALEXANDER BASIL. WILSON, of Holywood, in the County of Down, Ireland,
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 the regulation of the admission of steam to engine
cylinders, and it applies more particularly to single acting engines with rotating
admission and exhaust valves.
The object of the invention is the attainment of practically uniform speed in
steam engines irrespective of the power produced thereby, or of moderate
variations in the steam pressure, by the regulation of the quantity of steam
admitted to each end of each cylinder.
In an engine constructed according to this invention the amount of steam
admitted into each end of each cylinder, and which is equivalent to the portion
of the stroke of the piston during which the space swept through thereby is open
to the source of supply of steam, which portion is hereinafter called the cut-off,
(a long portion of the stroke being called a long cut-off, and a short portion
an carly cut-off) is regulated by the action of a centrifugal governor revolving at
a speed having a definite ratio to the speed of the engine in the well known
manner, the motion due to the change in radial distance of the centre of gravity
of the balls from the centre of revolution arising from variations in speed, being
made use of to regulate the extent of the cut-off.
In steam engines constructed in accordance with the Specification of Patent
No. 10160 of 1898, granted to me, the speed of the engine is regulated by a
governor working within the steam chest and throttling the admission of steam
to the cylinder or cylinders, and by such throttling a less complete use is made
of the energy of the steam passing through the steam-engine at varying powers,
than if the cut-off is varied by the governor according to the demand for power
and the pressure of steam available.
Now according to my present invention I place the governor, which may be of

page_text: the ordinary gravity or spring operated type, within the steam chest as described
in the Specification of my aforesaid Patent, and I so construct the said governor
that its motion is communicated to a cut off plate ring or valve, which cut-off
plate, ring or valve rotates at the same number of revolutions, or at half the
number of revolutions as the case may be, of the steam engine. The angular
advance of such plate, ring, or valve in relation to any point in the path of the
crank pin of such engines is determined by the position in or out of the governor
balls. In this plate, ring, or valve I arrange suitable ports.
This plate, ring, or valve, called hereinafter the governor valve, rotates on or
around a fixed plate, ring, or valve, or the equivalent of such, hereinafter called
the fixed valve. The surfaces of the governor valve and the fixed valve are
fitted together so as to be practically steam tight. In the fixed valve, I provide
a port or ports corresponding to those in the governor valve.
The passage way
through the aforesaid ports forms the means of entrance of the motive fluid into
the body of the main valve which admits steam to the cylinder during one
part of its revolution, and exhausts the steam from the cylinder during another
part of its revolution as described in the Specification of my aforesaid Patent.
This valve is hereinafter called the main valve.
The ports in the governor valve are so arranged in relation to the ports
in the fixed valve that when the governor balls are in their inmost position
the steam opening through the port of the governor valve into the port of the
fixed valve and from thence into the main valve corresponds in degree of opening
with the steam opening of the port of the main valve into the cylinder, and I
connect the governor valve to the governor, and so arrange the ports in it in
relation to the port of the fixed valve, that when the governor balls are in their
outward position the governor valve has so far covered the port in the fixed
valve that the passage through the ports is closed to the main valve, and at
intermediate positions of the governor balls the ports are open to a like proportion
of the degree that the governor balls are out; the cutting-off edge of the port of
the governor valve being advanced in relation to the revolution of the engine,
thus producing an carlier cut-off of the supply of steam as the balls fly out.
As it is sometimes desirable that the speed of the engine shall be able to be
reduced for a short time below its regular working rate, I provide means by which
the fixed valve can be rotated in such a direction that the complete cutting-off
action of the port edge of the governor valve takes place before the governor
balls are at their extreme distance out. Such rotation of the fixed valve may be
done by a lever or screw, or any convenient means.
As an example, if in an engine arranged to run at a speed of 400 revolu-
tions per minute with the governor balls at two thirds of their extreme distance
out, the governor is so arranged that the balls will run at their extreme distance
with the engine running at 408 revolutions, and that when the balls are at their
extreme distance, the opening through the valve is closed as aforesaid, and if
with the governor balls running at one-third their extreme distance out with
an engine speed of 392 revolutions, and with the balls at this position the
opening through the ports is sufficient to supply the engine with steam, then the
working range of speed is from 392 to 408 revolutions corresponding to the outer
two thirds of the position of the governor balls.
If therefore the governor runs at its inmost position at 384 revolutions per
minute, then by the alteration of the fixed valve in position, the cut-off action
of the governor can be made to take place between 384 and 400 revolutions in
place of between 392 and 408 revolution's.
The mean speed of the engine in the one case is 400 revs., and in the other
392 revs.
In the accompanying illustrative drawings:
1
Fig. 1 is a central vertical section through the steam chest of a vertical
single-acting engine, showing the valves and. the governor constructed in
1

page_text: Fig. 2 is a horizontal section on the line 2-2 of Fig. 1.
Fig. 3 is a part vertical section taken at right angles to Fig. 1.
Fig. 4 is a part horizontal section taken on the lines 4-4 and 4° -4° of Fig. 1,
showing the valves in the position in which they cut off the steam supply to
the cylinder.
A is the governor valve, B is the fixed valve, C is the main valve, D D are
the governor balls sliding on and driven by a guide frame E E; they are
connected to the governor valve by links F F. The balls are held in against
centrifugal force by springs G G which bear against the frame E E. The
fixed valve B is surrounded by the governor valve A, having ports a and b as
shown. The main valve C has a port c, corresponding to the cylinder port c c.
The fixed valve is retained in position by the spindle H which has a square
part provided on it at h corresponding to a square opening in the fixed valve B
so as to connect the two together. The spindle H has a flange H H, and can be
rotated through an opening in the casing cover J, by means of the square h h
when desired. It is secured in position by the nut P and washer por similar
means. The edge of the washer p may be graduated to suit a pointer on the
cover J.
The main valve spindle L rotates with the engine and drives the governor
through the frame E, it also drives the main valve C, but does not drive the
fixed valve B.
In Figure 1 no springs are shown, but they rest in the spring chamber gas
shown in Fig. 2 and Fig. 3.
The action of the governor is as follows:-Any variation in the speed of the
spindle L causes the balls D to assume a position of greater or less distance from
their centre of rotation and their movement and position is communicated by the
links F to the governor valve A, the ports of which thereby close sooner over the
ports in B as the balls assume an outward position, and later as they go inwards,
so that the passage of steam through the ports a and b is thereby varied
correspondingly. The rotation of the spindle H by varying the position of the
fixed valve B causes the closing action of the ports of the valve A to take
place with the balls at more or less distance out from their centre of rotation.
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. In a steam engine a fixed valve or its equivalent in combination with a
rotating main admission valve, and a rotating governor valve, for regulating the
admission of steam to the engine cylinder substantially as described and shown.
2. An arrangement for altering and adjusting the position of a fixed valve such
as referred to in the preceding claim, by rotating it in relation to the governor
valve for the purpose of altering the speed of the engine substantially as
described.
3. In a steam engine the combination of a rotating governor valve and an
adjustable fixed valve for the purpose of regulating the supply of steam to the
engine cylinder and varying their speed substantially as described and shown.
Dated this 6th day of June 1890
J. C. MEWBURN & ELLIS.
55 and 56. Chancery Lane, London,
Chartered Patent Agents.