Valves of Steam Engines and Compressed Air Engines.
Year: 1885

page_text: Valves of Steam Engines and Compressed Air Engines.
We JOHN HENRY TANGYE of Cornwall Works Soho in the County of Stafford
Mechanical Engineer and WILLIAM JOHNSON the younger of Moxley near
Wednesbury in the County of Stafford Mechanical Engineer do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN AUTOMATIC CUT-OFF
MECHANISM FOR THE SLIDE VALVES OF STEAM ENGINES AND COMPRESSED AIR
ENGINES to be as follows:-
"
Our invention consists in combining with the slide valves of steam engines and
compressed air engines an oscillating valve (or valves) and the appliances herein
after described for the purpose of automatically cutting off the steam or compressed
air at any desired position of the stroke of the slide valve and thereby using the
steam or air expansively and regulating the speed of the engine.
We will describe our invention as applied to a horizontal steam engine.
We mount upon the top of the ordinary slide valve of the steam engine an
oscillating valve having about the same length as and jointed at its middle to the
slide valve. The ends of the said oscillating valve are situated over the steam
ports in the slide valve. By the motion of the oscillating valve upon its joint or
centre one of the steam ports in the slide valve can be closed and the other at the
same time opened. Near the outer end of one arm of the oscillating valve is a
stop or pin and on the outer end of the other arm and on the opposite side is a
similar stop or pin. Situated in the steam chest are two sliding regulating bars
one bar being situated on one side and the other on the opposite side of the
oscillating valve for the stops or pins described on the oscillating valve to travel
upon. The said regulating bars are coupled together and are capable of a sliding
motion in opposite directions the said bars being acted upon by the governor of
the engine. The action of the cut-off mechanisin is as follows:-Assuming that
the slide valve is making its stroke from left to right the left hand end of the
oscillating valve is supported in its raised position during the first portion of its
stroke by the stop or pin on the said end of the oscillating valve travelling upon
the regulating bar. The stop or pin having travelled to the end of the regulating
bar and the port in the slide valve having been put into communication with the
steam passage to the cylinder the further motion of the slide valve causes the stop

page_text: to escape from the said regulating bar and the raised end of the oscillating valve
being no longer supported is closed against the face of the slide valve by the
pressure of the steam in the steam chest thereby cutting off steam to the cylinder
and using the said steam expansively. The same action takes place at the opposite
end of the oscillating valve when the motion of the slide valve is reversed.
In order to put the oscillating valve into equilibrium and thereby permit of the
ready descent of the raised end on the return stroke of the slide valve the steam
port in the slide valve under the closed end of the oscillating valve is put into
communication with the live steam in the steam chest thereby equalizing the
pressure on the said oscillating valve.
So long as the engine is working at its normal speed the steam is automatically
cut off at the proper times by the action of the oscillating valve and regulating
bars but when the speed of the engine exceeds its normal speed the governor
operates upon the regulating bars and gives them such a position that the steam
is cut off earlier by reducing the length of the travel of the stops over the
regulating bars.
We do not limit ourselves to the arrangement described of the two regulating
bars on opposite sides of the oscillating valve as the two regulating bars may be
arranged at the same side of the oscillating valve and be moved in opposite
directions when operated upon by the governor or the closing of the oscillating
valve may be effected by regulating bars crossing the ends of the said valve the said
crossing regulating bars 'being put into operation by the action of the governor.
Or the oscillating valve may be situated within the slide valve and between the
two ports in it and be operated mechanically by the governor or instead of a single
oscillating valve a jointed valve situated over each port in the slide valve may be
operated in the manner herein before described.

page_text: Valves of Steam Engines and Compressed Air Engines.
We JOHN HENRY TANGYE of Cornwall Works, Soho in the County of Stafford,
Mechanical Engineer, and WILLIAM JOHNSON the younger of Moxley near
Wednesbury in the County of Stafford, Mechanical Engineer do hereby declare
the nature of our Invention for "IMPROVEMENTS IN AUTOMATIC CUT-OFF MECHANISM
FOR THE SLIDE VALVES OF STEAM ENGINES AND COMPRESSED AIR ENGINES" and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
Our invention consists in combining with the slide valves of steam engines and
compressed air engines an oscillating valve (or valves) and the appliances herein-
after described for the purpose of automatically cutting off the steam or compressed
air at any desired position of the stroke of the slide valve and thereby using the
steam or air expansively and regulating the speed of the engine.
We will describe our invention as applied to a horizontal steam engine.
We mount upon the ordinary slide valve of the steam engine an oscillating flap
valve having about the same length as and jointed at its middle to the slide valve
The arms of the said oscillating valve are situated over the steam ports in the slide
valve.
By the motion of the oscillating valve upon its joint or centre one of the steam
ports in the slide valve can be closed and the other at the same time opened.
Near the outer end of one arm of the oscillating valve is a stop or pin and on
the outer end of the other arm and on the opposite side, is a similar stop or pin.
Situated in the steam chest are two sliding regulating bars, one bar being
situated on one side and the other on the opposite side of the oscillating valve for
the stops or pins described on the oscillating valve to travel upon.
The said regulating bars are coupled together by a lever and are capable of a
sliding motion in opposite directions, the said bars being acted upon by the governor
of the engine. The action of the cut off mechanism is as follows:-Assuming that
the slide valve is making its stroke from left to right, the left hand end of the
oscillating valve is supported in its raised position during the first portion of its
stroke by the stop or pin on the said end of the oscillating valve travelling upon
the regulating bar. The stop or pin having travelled to the end of the regulating
bar and the port in the slide valve having been put into communication with the
steam passage to the cylinder the further motion of the slide valve causes the stop
to escape from the said regulating bar and the raised end of the oscillating valve
being no longer supported is closed against the face of the slide valve by the
pressure of the steam in the steam chest, thereby cutting off steam to the cylinder
and using the said steam expansively. The same action takes place at the
opposite end of the oscillating valve when the motion of the slide valve is
reversed.
In order to put the oscillating valve into equilibrium and thereby permit of the
ready descent of the raised end on the return stroke of the slide valve the steam

page_text: port in the slide valve under the closed end of the oscillating valve is put into
communication with the live steam in the steam chest thereby equilizing the
pressure on the said oscillating valve.
So long as the engine is working at its normal speed the steam is automatically
cut off at the proper times by the action of the oscillating valve and regulating
bars but when the speed of the engine exceeds its normal speed the governor
operates upon the regulating bars and separates them to a greater distance and gives
them such a position that the steam is cut off earlier by reducing the length of the
travel of the stops over the regulating bars.
We do not limit ourselves to the arrangement described of the two regulating
bars on opposite sides of the oscillating valve as the two regulating bars may be
arranged at the same side of the oscillating valve and be moved in opposite
directions when operated upon by the governor; or the closing of the oscillating
valve may be effected by regulating bars crossing the ends of the said valve the
said crossing regulating bars being put into operation by the action of the
governor.
Or the oscillating valve may be situated within the slide valve and between the
two ports in it and be operated mechanically by the governor; or instead of a
single oscillating valve a jointed valve situated over each port in the slide valve
may be operated in the manner herein before described.
We will now proceed to describe with reference to the accompanying Drawing
the manner in which our invention is to be performed.
Figure 1 represents in side elevation and Figure 2 in plan the slide valve of a
steam engine to which an oscillating flap valve of the kind which we use applied;
Figure 3 represents a horizontal section of the slide valve and a portion of the
steam chest of the engine, together with the oscillating flap valve and regulating
bars and appliances connected therewith; Figure represents a plan of the
Oscillating flap valve and regulating, bars, the said Figures 3 and 4 being drawn to
a smaller scale than Figures 1 and 2. The same letters of reference indicate the
same parts in Figures 1, 2, 3 and 4; b is the ordinary slide valve of the steam
engine having in it the usual steam ports d, e and d² e² are the passages in the
steam chest f communicating respectively with the ends of the steam cylinder of
the engine. The slide valve b is worked in the ordinary way from the shaft of the
engine; a, a² is the flap valve mounted upon the slide valve b and oscillating upon
the centre c the said flap valve having about the same length as the slide valve.
The said flap valve a, a is situated over the ports d, e in the slide valve and the said
flap valve has the slightly cranked figure represented, that is, the two arms are
nearly but not quite in the same line so that by the motion of the said valve upon
its centre one arm of the valve closes the port dore and the other arm at the same
time opens the port d or e. Near the end of the arm a of the oscillating flap
valve a, a² is a stop or pin x and on the end of the other arm a² and on the
opposite side is a similar stop or pin x³, y¹, y' are two regulating bars capable of a
sliding motion in opposite directions the said bars being situated in the steam
chest and working in the guides p, p. The regulating bar y¹ is situated on one
side and the regulating bar y on the opposite side of the flap valve a, a³ (see
Figure 4). On the innerside of the regulating bar y¹ is a seat or projection qª for
the pin or stop of the flap valve to travel upon and on the innerside of the other
bar y, and at the opposite end of the flap valve, is a similar seat or projection q
for the stop or pin x on the flap valve to travel upon. As the slide valve b moves
in one or other direction the flap valve a, a' is caused to oscillate at the proper
times upon its joint c in the manner herein after described for alternately opening
and closing the steam ports in the said slide valve.
The length of the travel of the pins x, x upon the seats q, q² so as to regulate
the cut off of the steam is effected by separating the said seats q, q² to a greater or
less distance apart. This is automatically effected by sliding the regulating bars y¹, y³
in opposite directions by the action of the governor of the engine. This action is
obtained by coupling the regulating bars y¹, y together by means of the lever

page_text: (see Figures 3 and 4) the projecting axis or spindle of
upon it. This crank arm is connected through the rod
engine.
which has a crank arın
with the governor of the
When the slide valve is working from left to right or in the direction indicated
by the arrow in Figure 3, the flap valve a, a² travels in the same direction and has
the position represented in the said Figure 3; that is, the arm a³ of the valve is
shut down upon the port e so as to close it and the other arm a is removed from
off and opens the other port d during the first portion of the stroke of the slide
valve, the a arm a being supported in its open position by the stop or pin x
travelling upon the seat 9 on the regulating bar y². The stop or pin x having
travelled to the end of the seat q. and the port d in the slide valve b'having been
put in communication with the steam passage de to the cylinder the further motion
of the slide valve in the same direction causes the stop x to escape from the seat q
of the regulating bar y² and the arm a of the flap valve being no longer supported
is closed against the face of the slide valve by the steam in the steam chest f the
same motion of the slide valve also removing the stop from the seat 2 of the
regulating bar y¹ and permitting the oscillating flap valve to turn upon its centre.
The steam in the steam cliest is thus cut off from the cylinder the steam supplied
to the cylinder being used expansively.
The same action takes place at the opposite end of the oscillating valve when
the motion of the slide valve is reversed, that is the pin on the now closed arm a
of the valve a, u in its back motion travels on the opposite face of its seat q to:
maintain the said arm in its closed position, the escaping of the pins x and x" from
the seats q and q² causing the arm a to close the port d and the opposite arm a² to
open the port e in the slide valve. So long as the engine is working at its normal
speed the steam is automatically cut off at the proper times, by the action of the
oscillating valve, a² and its pins or stops x, x and regulating bars y¹, y²; q, q² but
when the speed of the engine exceeds its normal speed the governor acting through
the rod ³arın ³ and coupling lever gives a sliding motion in opposite directions
to the regulating bars y¹, y² and thereby separates the seats q, q² on the said bars.
The steam is in this way cut off earlier by reducing the length of the travel of the
stops x, x over the seats q, q of the regulating bars as will be understood by an
examination of Figures 3 and 4.
The steam ports in the slide valve may be arranged as represented in Figure 5
that is, the faces of the two ports d, è may be inclined to one another instead of
being in the saine plane. The oscillating Hap valve a, a² and the regulator bar 1, 2
operating the said valve, have the respective figures represented in the Drawing.
The regulator bar 1, 2 is connected to and operated by the governor. Or the
ports d, e may each have a flap valve as represented in Figure 6, where the valves
are marked a, a². In order to operate these valves the regulator bar is made as
represented in the said Figure 6, that is, it consists of the two curved arms 6 and 7
so mounted on the shaft 8 that the motion of the slide valve over the said arms
operates the flap valves u and a in the required manner. The positions of the
regulating arms 6 and 7 are governed by the governor of the engine acting upon
the shaft 8 on which they are mounted.
Instead of the oscillating flap valve being jointed to and travelling with the
slide valve as described the said oscillating flap valve may turn in a bearing fixed
in the steam chest, the arms of the flap valve being so arranged with respect to the
slide valve as to alternately open and close the stean ports in the slide valve.
This modification of our invention is represented in horizontal section in Figure 7
and side elevation in Figure 8.
In this modification the oscillating Hap valve a, a² is actuated by a regulating
bar in the form of a tappet or lover arm j jointed to the bearing in the steam
chest carrying the flap valve. A reciprocating motion is given to the said tappet
or lever arinj through the rod ² on the end of which the link works the latter
being connected through the rod with an eccentric on the shaft of the engine.
The said link is also raised and lowered by the action of the governor. After the

page_text: slide valve has made a portion of its stroke from left to right the action of the
eccentric moves the rod 72 in the direction of the arrow in Figure 7 and turns
the tappet or lever arm j upon its centre. The head of the said tappet or lever arm
is thereby made to lift the arm a of the flap-valve and close the port d, the other
arm a² opening the port e. In this way the steam is cut off at the required
position of the stroke of the slide valve. The length of the travel of the tappet or
lever arm is determined by the position of the link k the position of the latter
being regulated through the governor of the engine:
3
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we déclare that we
claim as our invention of "Improvements in automatic cut off mechanism for the
slide valves of steam engines and compressed air engines".
First. The combination with the slide valves of steam engines and compressed
air engines of an oscillating flap valve or valves and appliances for operating the
said flap valve or valves substantially as herein before described and illustrated in
Figures 1, 2, 3 and 4 of the accompanying Drawing.
Secondly. The modifications hereinbefore described and represented in Figures 5
and 6 of the accompanying Drawing whereby the oscillating flap valve or valves is
or are operated by a regulator or regulating bars having an angular motion.
.
Thirdly. The modification herein before described and represented in Figures 7
and 8 of the accompanying Drawing in which the oscillating flap valve or valves is
or are detached from the slide valve and turn upon a fixed centre in the steam or
compressed air chest of the engine, the said flap valve or valves being operated
substantially as described and illustrated.
Dated this Tenth day of November 1885.