Improvements in or relating to Valve Mechanism for Engines.
Year: 1894

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Valve Mechanism for Engines.
1, WILLIAM ALFRED DREWETT of 130 Rutledge Street, Brooklyn, King's
County, State of New York, United States of America, Mechanical 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 that class of engines in which the valves are moved for
a part of the distance by some operating part of the engine and the movement is
then completed by the pressure of the motor fluid; and my invention consists in
constructing the valve operating devices as fully set forth hereinafter and as
illustrated in the accompanying drawings in which:
Fig. 1 is a longitudinal sectional elevation of a steam engine provided with my
improved valve device.
Fig. 2 is a like elevation showing the parts in a different position.
Fig. 3 is a longitudinal section of the valve device enlarged.
Fig. 4 is a transverse section on the line 4-4, Fig. 3.
Fig. 5 is a transverse section illustrating said valve operating devices in
connection with control devices embodying my improvement.
Fig. 6 is an enlarged section of valve control devices, taken on line 5-5,
Fig. 5.
Fig. 7 is a diagrammatic view illustrating in plan the arrangement and connection
of engines in direct acting duplex engines embodying these improvements.
"
This invention is illustrated in connection with "direct acting duplex engines'
arranged as shown diagrammatically in Fig. 7, where there are two engines I, J, each
provided with a valve device A, the valve of each device having connections with
a moving part of the other engine, which imparts motion to said valve.
The valve device A, may be used with any suitable construction of engine having
a cylinder B, piston C, piston rod D, inlet ports 5, 6, extending to the ends of the
cylinder and exhaust port 7, all extending to a face upon which slides a
D" or
other valve E.
66
The valve casing 8, of the valve device A, is preferably a cylinder within which
slides a hollow cylindrical valve piston F, to which the valve E, is connected, or of
which it forms a part, steam passing to the interior of said piston from the inlet
pipe 9, and passing from the said piston to the ports 5, 6, through ports 10, 12,
according to the position of the piston and its valve E, the escaped steam passing
from ports 5, 6, to the port 7, through the valve E, as usual.
My improved valve device is of that class in which the valve after having
been carried to either extreme position is moved to a certain extent from some
moving part of the engine, and while there is full steam pressure upon both ends
of the valve operating piston, and is then shifted by the steam pressure at one
end of the said piston when the pressure at the opposite end is reduced by
exhausting the steam from said piston; and in order to reduce the cost and
avoid the complexity of such constructions wherein this result is obtained
I combine with the parts above described the features which I will now set
forth.
4

page_text: With the interior of the casing 8, at any suitable points between the centre
and the ends communicate two ports 14, 15, from each of which a channel leads
to the exhaust 7, and each of these ports is controlled by a supplemental valve
in the construction shown, which is in part, a part t, of the piston, and in part
an independent sliding section or valve 16 or 17, which may be an annular or
ring valve within an annular chamber or recess e, in the piston F, as shown,
but whatever the construction may be, the said valve is of such character that
the sliding movements of the piston will cause the supplemental ports to be
opened and closed at proper times. In the construction shown where there are
two ring valves 16, 17, in annular recesses or chambers in the piston, the said
recesses are of such size that the piston may move to a limited extent indepen-
dently of the valves, which will remain in place by frictional contact with the
bore of the casing until the slides of the recesses in the piston, or other contact
shoulders or projections are brought against the edges of the valves and shift
them.
In each end of the piston F, there is a small port or channel a sufficient to
permit the steam to escape from the interior of the piston into the chamber,,
at the opposite ends thereof to balance the piston until the pressure is relieved
at one end or the other, in which case the preponderating pressure at the
opposite end will throw the piston and its valve. This pressure is relieved at
one end or the other of the piston after the latter has been moved to a certain
extent towards the said end by the action of the engine, by opening a communi-
cation between said end chamber 2, and the port 14 or 15, through a port or
channel, communicating with the chamber of the valve 16 or 17. In the
construction shown a channel y, of a greater cross-sectional area than the
perforation, extends from each end of the piston to the annular chamber e,
containing the valve 14 or 15.
Any suitable connection may be made between a moving part of the engine and
the piston F. As shown, the spindle 19, of the piston F, carries two stops 20, 21,
secured adjustably thereto, and between which plays a block 22, reciprocated from
'the piston rod D, through the medium of a lever 23, and connecting rod 24.
Assuming the parts to be in the position shown in Fig. 1, with the valve piston F,
at the right, and the main piston C travelling in the direction of its arrow towards
the right, the block 22, as the piston C, approaches the end of its stroke will be
brought against the contact 20, and the piston F, will be moved by the engine until
the chamber e, at the left of the piston F, is brought over and communicates with
the port 14, when the steam will escape from the chamber z, at the left of the piston
through the channel y, and chamber e, and flow through the exhaust port 14, and
thence 'to the exhaust port 7, suddenly reducing the pressure at the left of the piston
so that the preponderating pressure at the right will throw the said piston to the
left, as in Fig. 2, just as the main piston C, reaches the end of the cylinder at the
right, when the said end of the cylinder will be put in communication with the inlet
steam port and passage while the space at the left of the main piston will be put in
communication with the exhaust.
As the piston F, reaches its position at the left the valve 16, is brought in position
to cover the port 14, the valve 17, is carried from the port 15, which is covered by
a part t, of the piston, so that when the piston F, is moved to the right by the
action of the engine as the piston C, approaches the left position, the valve 16, has
closed the port 14, against the passage of steam, but steam can pass from the right
hand end of the piston F, to the port 15, as soon as the part t, of the piston uncovers
the port and the channel or chamber e, is thus brought to communicate with said
port 15, when the pressure at the right of the piston F, is relieved and said piston
is thrown to the right by the preponderating pressure at the left, and then the
valve 17, is brought above the port 15, while the valve 16, the part t to the left,
still covers the port 14.
It will be seen that by the construction above set forth, I am enabled to positively
shift the valve E, regularly and with certainty, and to effect. this result by appliances

page_text: of an extremely simple character that can be constructed at practically a fraction of the
expense heretofore required for mechanism for securing the same results. Thus it will
be seen that there is no forging or hand fitting as the valve casing can be finished by
usual operations in a boring machine the chambers in piston F, may be formed by
the tools of a lathe or slotter; the valves 14 and 15, may be split rings sprung into
place, and when the chambers e, are formed by slotting across the piston, said valves
may consist of simple metal blocks. It will be evident that no packing is required
except between the ports 10 and 12, and the chambers e, e, where there are two
ring packings 30 30, simple in character and durable inasmuch as they do not have
to traverse any of the ports. Additional packings 39, are shown, but they may be
dispensed with.
While I have referred to the chambers at the ends of the valve casing as being
in communication with the piston F, through the perforations x, x, it will be evident
that the said perforations a, may be in the valve casing near the ends and commu-
nicate with any part of the steam supply chambers or channels with like effect.
It will be seen that as the pressure is always on the top of the valves 16, 17, and
the exhaust below, they will be kept firmly to their seats. It will also be seen
that by making the chambers, or arranging the contacting shoulders that move
said valves, so as to allow the piston to move independently of the valve
sections 16, 17, to a limited extent, and by providing the parts t, t, on said piston
to act as parts of the auxiliary valves for closing and opening the ports 14, 15, I
am enabled to close one port as the piston moves to one end, then move the piston
back to an extent sufficient to open the other port, and then shift the valve of the
first port to such a position (without opening said port) that on the return movement
of the piston, the port will be first put in communication with the chamber and
then on the further movement of the piston, be closed by said valve. Each port is
thus opened to permit the steam to exhaust from the adjacent chamber z, and is
then closed to prevent such exhaust on the return movement of the piston F.
e,
In connection with the devices described, or with any other valve device in
which there is normally an equal pressure at opposite ends of the valve operating
piston, with means for relieving the pressure at either end to shift the valve,
I make use of the devices which I will now describe, and which are shown in
Figs. 3 to 6.
T, is a valve casing of an auxiliary valve device containing a channel 9, which
communicates with a valve chamber w, and also at each end with a port 31; a.
channel 32, leading to each port 31, from one of the ports 14 or 15, of the valve
device described, or with the corresponding exhaust ports of any other available
form of valve device.
A port 34, leading to the chamber w, connects with a channel extending to the
exhaust port 36, and this port 34, is controlled by any suitable valve, as for
instance a rocking valve G, upon a rock-shaft 37, extending through the casing of
the valve device T, and provided with an arm 38,.connected through any suitable
connections with any moving part of the opposite engine.
The valve operating piston of the engine cannot be actuated by the exhausting
of the steam from either end of said piston, even when the engine valves are in
position to permit such exhaust, until the valve G is moved by the opposite engine
to open communication between the chamber w, and the exhaust port 34, but when
the valve G thus opens the exhaust port 34, the steam will at once be permitted to
escape from one of the chambers z, when the preponderating pressure in the
opposite chamber will shift the piston and its valve.
It will thus be seen that the valve device T, is of such a character that each
engine controls a valve that governs the exhaust from the valve piston operating
chambers of the other engine, to thereby so shift the valve of such other engine as
to insure unison of action between the two engines.
Different forms of valves and different arrangements may be employed with like
effect.
In my improved engine, no shifting of the valves or disconnecting of the parts

page_text: is necessary to make repairs if one engine gets out of order. Thus, I provide a
by-pass or channel d, connecting the chamber w, with the exhaust 36, and in this
channel d, I place a valve 40, of any suitable character. As shown, there is a
disc valve operated from a handle 41, outside of the casing T. Normally the
channel d, is closed, but when I desire to put one of the engines out of operation,
I open the channel d, of the other engine, when the exhaust steam from the casing
of the valve operating piston will escape through the ports 31, channel 9, and
channel d, to the exhaust 36, so that the valves of the engine in operation will be
controlled wholly by the valve operating devices of said engine, the exhaust under
the action of said devices passing directly to the port 36, without in any way being
controlled by the valve G. It will thus be seen that I form a by-pass channel
around the valve G, controlled by a valve which may be opened to practically put
the said valve G, out of operation without the necessity of disconnecting the said
valve from its moving devices or of shifting any of the valves to the apparatus
except the valve that controls the by-pass channel.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I wish it to be
understood that without limiting myself to the precise construction and arrange-
ments shown and described, what I claim is ;-
1. The combination with a piston and cylinder of a steam engine having inlet
and exhaust ports and passages a main valve controlling the same and a valve
controlling piston in a valve casing and means for moving said piston from the
engine to a limited extent from each end of the casing, of a contracted steam inlet
channel or port communicating with each end of the casing an exhaust channel
leading from the main exhaust port to a supplemental exhaust port between the
main exhaust port and each end of the casing a channel leading from each end of
the valve operating piston to the supplemental exhaust port and a supplemental
alve controlling the channel between each supplemental port and the main
xhaust port and means for shifting said supplemental valve by the valve operating
iston substantially as set forth.
2. The combination of the valve casing having main ports communicating with
e ends of the cylinder an exhaust port and supplemental ports communicating
ith the exhaust valves sliding over said supplemental ports and a piston having
oulders arranged to make contact with and move said valves while permitting a
limited independent movement of the piston, substantially as described.
3. The combination in a valve device of a casing having ports 5, 6, and 7, and a
valve controlling the same and supplemental exhaust ports 14, 15, communicating
with the port 7 a piston operating the main valve and provided with chambers e
containing supplemental valves controlling the supplemental ports and channels
between the ends of the piston and the chambers e substantially as set forth.
4. In a direct acting duplex engine the combination with the main valve of each
engine piston for actuating the same means for imparting initial movements to said
piston and exhaust valves and ports for exhausting the pressure at the ends of said
piston of a valve device having an exhaust port passages communicating with the
ports of said exhaust valves, and a valve controlling said exhaust port and devices
for operating said valve connected with a moving part of the other engine
substantially as set forth.
5. The combination in a direct acting duplex engine, of the main valve of one
engine the operating piston of said valve and means for actuating the same supple-
mental exhaust ports and means whereby said supplemental ports are controlled
and a casing with which said exhaust ports communicate and provided with an
exhaust port, as 34 a valve controlling the exhaust port 34 and connections between
said valve and a moving part of the other engine, substantially as set forth.
6. The combination with the main valve valve operating piston and means for
actuating the same and supplemental valves and ports of an engine of a casing
having a chamber communicating with said supplemental ports and provided with

page_text: an exhaust port and valve and a by-pass channel as d extending from said chamber
to the exhaust port of the engine and provided with a valve, substantially as and
for the purpose set forth.
البحر
A1 1004
W. P. THOMPSON & BOULT,
Agents for the Applicant.