Improvements in Expansion Valve Gear for Steam Engines, also Applicable to other Valve Gear.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
Improvements in Expansion Valve Gear for Steam Engines, also
Applicable to other Valve Gear.
We, CHARLES JOHN GALLOWAY and JOHN HENRY BECKWITH both of Knott
Mill Iron Works, Manchester in the County of Lancaster, Engineers, do hereby
declare the nature of this invention to be as follows:-
Our invention has mainly for its object to adapt the ordinary slide valve with
expansion plate to work with a tripping expansion motion in such manner that the
expansion plate, while receiving its motion from the same excentric as the main slide,
is closed sooner or later by the action of the governor with a quick tripping motion
for effecting the cut off.
For this purpose a rod or bar sliding in guides and connected at one end to the
main slide valve and at the other end to the excentric rod, carries the spindle of the
expansion plate, which is connected thereto by an elastic connection, whereby, while
the spindle with its expansion plate is free to move to and fro relatively to the said
bar and main slide, the elastic connection tends always to bring the spindle back to a
middle position, in which the expansion slide closes the steam passage or passages of
the main slide. By preference we construct the elastic connecting device as follows.
The sliding bar of the slide valve carries a pivotted arm or crank, the pin of which is
connected to the expansion-plate spindle and on the axis of this crank is a double
ended lever with curved or flat under surface against which presses the flat or curved
surface of a frame, also carried by the sliding bar, and which is urged upward by a
spring so as to tend to keep the double ended lever in its middle position, in which it
also holds the expansion plate.spindle in the middle or closed position by means of the
crank. When the expansion plate is held in this position while moving to and fro
together with the slide valve, it will be seen that no steam will enter the cylinder, and
5 Price 8d. Í

page_text: consequently in order to admit steam during a certain part of the stroke, the expansion
plate must be prevented during a certain interval of time from moving together with
the slide valve; or in other words, it must be held back, so as to uncover the steam
passage of the slide valve and allow steam to enter during a certain part of the stroke,
after which it must be liberated so as to allow it to be brought quickly back to its
middle position by the above mentioned elastic connection. We effect this by a
tripping device of the following arrangement.
On the expansion-plate spindle is a projecting plate, on each side of which are two
opposite pawls or catches on a fixed bracket, which, when not actuated, present their
extremities on each side of the plate, and in thus preventing this, and consequently
the spindle and expansion plate from moving while the slide valve is performing its
strokes, causes the steam passage of the slide valve to be opened as long as the steam
port of the cylinder is open. If on the other hand, as the expansion plate spindle
moves to and fro with the slide valve, these catches were alternately raised so as not
to come in contact at all with the plate on the rod as it passes, the expansion plate
would remain in the middle position and no steam would be admitted; if however as
the spindle moves in the one direction or the other, the corresponding catch he
allowed to drop so as to obstruct the farther movement of the spindle and to remain
so far a certain length of time the expansion plate will uncover the steam passage
during a corresponding length of time after which, the catch being raised, the spindle
will be liberated, and the expansion plate will be brought back to the middle position,
closing the steam passage, by the elastic connection.
The above described action on the tripping catches may be effected in various ways
from the slide valve eccentric and the governor, for varying the amount of cut off. Thus
according to one arrangement the eccentric rod is connected to a link motion in the
slot of which is a sliding block connected to the governor and also by a rod to a
tappet situated between two tails of the said catches, so that as the link motion is
moved to and fro by the excentric it imparts a greater or less to and fro motion to
the tappet, and the latter, in coming in contact with the tail of the catches, raises
these for a greater or shorter length of time, according to the extent of motion
imparted to the tappet, and thus effects the stopping and liberating of the expansion-
plate spindle as above described.
In order to avoid wear due to the coming in contact of the catches with the edges
of the tripping plate while this is moving with some speed, as may happen when the
engine is running fast, we prefer to attach the tripping plate to the expansion plate
spindle by means of an elastic device which will allow it to yield to a slight extent in
either direction when the catches come in contact therewith.
a
This elastic connection is by preference effected by forming on the tripping plate
curved loop passing through a slot in the rod and containing a curved block on a
lever pivotted at one end to the rod and bearing at the other end with an adjusting
screw upon a spring disc, so that the tripping plate is held in a central position by the
elastic pressure of the lever's block upon the curved surface of the loop, and when,
by the impact of the catches against the tripping plate, this is pushed slightly
to one side, the said spring action will tend to bring it back to the central position
again.
The above described valve gear may also be applied to expansion slide valves that
work on a fixed valve face with admission port or ports, instead of upon the main
slide. In this case the before described spindle with crank and double ended curved
lever, together with the frame and spring operating together therewith, instead of
being carried by the sliding bar of the main slide valve, are carried by a fixed part of
the engine, so that they tend to bring the expansion slide to a fixed middle position,
in which the steam port is closed thereby. The catches of the tripping gear would in
this case he carried by the sliding bar of the main slide, instead of by a fixed bracket,
so as, in moving to and fro, to push the expansion slide out of its middle position
and open the steam port, or, when raised out of gear, to allow this to be closed by
the slide.

page_text: The said valve gear is also applicable to a stamper valve which requires to be lifted
twice in every revolution of the crank shaft. The spring mechanism for bringing
the expansion slide to the middle position may also be used for bringing to rest the
semirotating valves of the Corliss Engine, in place of the usual dash pot or air
5 cushion.
Dated this 10th day of June 1888.
ABEL & IMRAY,
Agents for the Applicants.
CUMI LEIE
Improvements in Expansion Valve Gear for Steam Engines, also
Applicable to other Valve Gear.
We, CHARLES JOHN GALLOWAY and JOHN HENRY BECKWITH, both of Knott
Mill Iron Works Manchester in the County of Lancaster Engineers do hereby
declare the nature of this Invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement
Our Invention has mainly for its object to adapt the ordinary slide valve with
expansion plate to work with a tripping expansion motion in such manner that the
expansion plate, while receiving its motion from the same eccentric as the main slide,
is closed sooner or later by the action of the governor with a quick tripping motion
for effecting the cut off.
For this purpose a rod or bar sliding in guides and connected at one end to the
main slide valve and at the other end to the eccentric rod carries the spindle of the
expansion plate which is connected thereto by an elastic connection, whereby, while
the spindle with its expansion plate is free to move to and fro relatively to the said
bar and main slide, the elastic connection tends always to bring the spindle back to
a middle position in which the expansion slide closes the steam passage or passages of
the main slide.
According to one arrangement we construct the elastic connecting device as
follows: The sliding bar of the slide valve carries a pivotted arm or crank, the pin
of which is connected to the expansion plate spindle, and on the axis of this crank is
a double ended lever with curved or flat under surface, against which presses the
flat or curved surface of a frame, also carried by the sliding bar, and which is urged
upward by a spring, so as to tend to keep the double ended lever in its middle
position, in which it also holds the expansion plate spindle in the middle or closed
position by means of the crank.

page_text: When the expansion plate is held in this position while moving to and fro together
with the slide valve it will be seen that no steam will. enter the cylinder, and con-
sequently in order to admit steam during a certain part of the stroke, the expansion
plate must be prevented during a certain interval of time from moving together
with the slide valve; or in other words, it must be held back so as to uncover the
steam passage of the slide valve and allow steam to enter during a certain part of
the stroke, after which it must be liberated so as to allow it to be brought quickly
back to its middle position by the above mentioned elastic connection. We effect this
by a tripping device of the following arrangement.
On the expansion plate spindle is a projecting plate on each side of which are two
opposite pawls or catches on a fixed bracket, which, when not actuated, present their
extremities on each side of the plate, and in thus preventing this, and consequently
the spindle and expansion plate, from moving while the slide valve is performing its
stroke, causes the steam passage of the slide valve to be opened as long as the steam
port of the cylinder is open. If on the other hand, as the expansion plate spindle
moves to and fro with the slide valve, these catches were alternately raised so as not
to come in contact at all with the plate on the rod as it passes, the expansion plate
would remain in the middle position and no steam would be admitted; if however as
the spindle moves in the one direction or the other, the corresponding catch be allowed
to drop so as to obstruct the farther movement of the spindle and to remain so for a
certain length of time, the expansion plate will uncover the steam passage during a
corresponding length of time after which the catch being raised the spindle will be
liberated and the expansion plate will be brought back to the middle position closing
the steam passage by the elastic connection.
The above described action on the tripping catches may be effected in various ways
from the slide valve eccentric and the governor, for varying the amount of cut-off.
Thus according to one arrangement the eccentric rod is connected to a link motion in
the, slot of which is a sliding block connected to the governor, and also by a rod to a
tappet situated between two tails of the said catches, so that as the link motion is
moved to and fro by the eccentric, it imparts a greater or less to and fro motion to the
tappet, and the latter in coming in contact with the tail of the catches, raises these for
a greater or shorter length of time according to the extent of motion imparted to the
tappet and thus effects the stopping and liberating of the expansion plate spindle as
above described.
In order to avoid wear due to the coming in contact of the catches with the edges
of the tripping plate while this is moving with some speed, as may happen when the
engine is running fast, we prefer to attach the tripping plate to the expansion plate
spindle by means of an elastic device which will allow it to yield to a slight extent in
either direction when the catches come in contact: therewith.
Other modifications will be presently described with reference to the drawings.
Figures 1 to 5 of the accompanying drawings show our above described invention
applied to an ordinary slide valve with expansion plate. Figure 1 shews a side
elevation. Figure 2 shews a sectional plan and Figures 3. 4 and 5 shew enlarged
details.
The slide valve A. is connected to the rod of the eccentric B by means of a bar C
carrying in a bracket C an axis D having thereon a crank D' and double ended
lever D as shewn more clearly in the cross section at Figure 4. The pin of the
crank enters a sliding block E in the slot of the spindle F of the expansion plate F,
this spindle being carried in loops C2 C2 on the bar C so as to be free to slide to and
fro relatively to the bar C.
The bar also carries a helical spring G through which passes a rod 'attached at
one end to the bar C and having at the other end a head H which is presented to
the double ended lever D². The head H bears with a rounded face against a flat
face of the lever D2 which has a bead at each end fitting corresponding recesses
in the head.
The spindle F¹ carries a plate I having a projection I¹ to either side of which
are presented the ends of two catches J J pivotted to a bracket K on the engine

page_text: framing and having tails JJ' between which is situated a tappet lever L connected
by rod L and levers to the eccentric B.
The tappet lever L is pivotted to an arm M carried by the bracket on the engine
frame and connected by lever M¹ and rod M² to the governor of the engine.
From this arrangement it will be seen that the bar C of the slide valve A in being
actuated by the eccentric B will be made to carry the spindle F of the expansion
plate with it in either direction by means of the crank D¹ unless this is prevented
by the tripping catches JJ, and that during such motion the plate F will be in the
middle position in which it closes the steam inlet of the slide valve.
If however during such motion one of the tripping catches J be presented in the
path of the projection I¹ of the plate I so as to prevent the motion of the spindle F¹
and plate F while the valve A continues to move, the inlet port of the slide valve. will
be uncovered so as to admit steam to the cylinder.
When the motion of F¹ is arrested in this manner its crank connection with the axis D
will cause this to be turned somewhat, and the lever 12 will thereby be made to
force back the head H and compress the spring Gas indicated at Figure 5. As soon
as the catch J that holds F¹ is raised by the action of the tappet lever. L on its
tail J, the spindle and expansion plate are rapidly brought back to their middle
position by the action of the spring G and head H on the lever D² which, together
with the crank D', is brought back to the middle position Figures 1.and 3. By
rounding the face either of the head H or the lever D² such return to the. middle
position is effected without shock or noise.
It will be seen that the tappet lever L is connected to the eccentric B in such a
manner that on the rotation of the latter the tappet will at the commencement of the
stroke of the valve in one direction, leave the catch J situated on the side lying
in that direction in the path of the projection I', so as to cause the expansion: plate
to uncover the steam inlet, but after the slide has performed a certain part of that
stroke, the tappet lever L will be moved so as to raise the catch J, and, in thu
allowing the plate F to spring back to its middle position, effect the cut off.
The tappet lever L being mounted on the lever M controlled by the governor, it
will be seen that when the speed of the engine increases above the normal, the
governor in causing the pivot of the lever to be raised will advance the movement at
which the lever L comes in contact with the tail of the catch, and will consequently
make the cut off take place earlier while the converse will take place when the
engine runs too slow.
To prevent wear of the edges of the catches J J and projection I as much as
possible, it is preferred to connect the plate I in an elastic manner to the valve
spindle F so that the projection can yield slightly to the impact of the catch when
moving at a high speed.
For this purpose a construction is employed which will be more clearly under-
stood on reference to Figure 6 shewing this device in connection with a different
arrangement of the tripping gear.
The plate 1 has on its underside a loop 12 passing through a slot in the spindle F1;
in the curved bottom of this loop is, a block P carried by a pin on a lever P¹, one end
of which is pivotted to the spindle F1 while the other end bears with an adjusting
screw P2 on a disc spring Q carried by F¹.
Thus it will be seen that when either of the catches J comes in contact with the
projection with a certain degree of force, and thereby pushes the plate I slightly to
the one side or the other, the curved loop I2 will draw up the block P and lever P¹
against the action of the spring Q.
Figures 7 and 8 shew respectively a sectional elevation and a sectional plan of a
modification of the above described expansion gear, in which the expansion plate F
is situated in a separate valve chest and works on a fixed valve face. In this case the
axis 1) with its crank D¹ and double ended lever D2 as also the spring G and head_H
are carried by a fixed bracket K on the engine frame, while the tripping catches J J
are carried by the slide valve bar G, the plate I with projection I¹ being, us before, on
the expansion plate spindle.

page_text: The governor actuates two tappets L L in such manner that when the engine is
running too fast, the ends of the tappets are moved outwards, while they are moved
inwards when the engine runs too slow.
On the commencement of the eccentrics' stroke, the one or the other catch carries
with it the spindle F', thus causing the expansion slide to open the steam port while
at the same time the crank D¹, being carried along with F¹ effects the compression of
the spring Gas above described, until the tail of the catch is brought in contact with
the tappet L when the catch being raised out of gear with I¹ the spring G will force
the spindle F¹ and slide F back into the middle position, thus effecting the cut-off.
Figure 9 shews the application of the before described lever and spring device
to the gear of Corliss valves in place of the usual dash pot or air cushion for bringing
them back to the closed position.
The levers D are for this purpose fixed on the valve spindles and acts against the
heads H of the springs G as above described, the stems carrying the springs being
pivotted to the bracket R of the engine; so that when the levers D₁ of the valves are
acted upon by the tripping gear (which may be of any known construction) so as to
bring the valves into the open position, the levers D₁ are made to compress the
springs, as shewn on the right hand side, while when the tripping gear releases the
levers 11, the springs G force the valves back into the closed position, as shewn on
the left hand side.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The use, in combination with a slide valve and its expansion slide or plate, of an
elastic connection between their rods or spindles, so arranged that the main slide is
made to carry the expansion slide with it, unless the latter is retained by a tripping
device, the expansion slide being made to resume its original position when released
by the tripping gear, substantially as and for the purpose herein described.
2. In expansion slide valve gear, carrying the spindle of the expansion slide or plate
by the rod or bar of the main slide, and connecting it thereto by an elastic connection
which holds the expansion slide in the middle position and allows of its relative motion
in either direction, such mechanism being so combined with tripping gear that the
latter holds the expansion slide stationary during part of the stroke of the main slide,
so as to uncover the steam port of the latter while on the release of the expansion
slide by the tripping gear, the expansion slide is brought back into the middle
position, in which it effects the cut off substantially as herein described with reference
to Figures 1 to 5. of the drawings.
3. In expansion valve gear constructed and operating as set forth in the preceding
claims the use of a helical spring such as G with head H carried by the rod of the
main slide operating in combination with a double ended lever D² on an axis D, also
carried by the main slide rod, and having a crank D' that is connected to the expansion
slide spindle substantially as and for the purposes described with reference to
Figures 1 to 5.
4. In combination with valve gear constructed and operating as set forth in the
preceding claims, the use of tripping catches such as J J carried by a fixed support,
acting on a plate II on the expansion slide spindle and operated by a tappet lever
acted upon both by the eccentric of the main slide and by the governor in such
manner that the catches are made to release the expansion slide sooner or later
according to the degree of cut off required, substantially as described with reference
to Figures 1 to 5 of the drawings.
5. In combination with a slide valve and an expansion slide working on a fixed
valve face, the use of tripping catches carried by the main slide rod which carry the
expansion slide spindle with them against the action of a spring device so arranged as
to bring the expansion slide back to the middle position when it is released from the
tripping catches substantially as and for the purposes herein described with reference
to Figures 6. 7. and 8 of the drawings.

page_text: 6. In expansion valve gear constructed and operating as set forth in the preceding
claim, the use of tripping catches such as J J. carried by the main slide rod, and
made to carry with them the expansion slide spindle the latter being connected by a
crank D¹ to a lever D² carried by a fixed spindle D and operated by a spring G with
head H in such manner that when the tripping levers are made to release the
expansion slide spindle by the action of tappets L actuated by the governor, the said
spring device brings the expansion slide back to the middle position, substantially as
described with reference to Figures 6, 7 and 8 of the drawings.
7. In tripping gear for slide valves, connecting the plate on which the tripping
catches act, to its slide-rod by means of an elastic connection arranged and operating
substantially as herein described with reference to Figure 6 of the drawings for
the purposes set forth.
8. The use for controlling the motion of slide valves, of a spring device consisting
of a spring G with head H operating in combination with a lever D³ connected
directly or indirectly to the valve for bringing it to a position of rest, the acting face
either of the head or of the lever being rounded so as to prevent shock when
coming to the position of rest, substantially as herein described with reference to
the drawings.
1 1000