Improvements in and appertaining to the Valve Gear of Duplex Direct Acting Engines.
Year: 1893

page_text: Date of Application, 3rd May, 1893-Accepted, 24th June, 1893
COMPLETE SPECIFICATION.
Improvements in and appertaining to the Valve Gear of Duplex
Direct Acting Engines.
We, HERBERT William Morley, of 54 Ash Grove, Bradford, in the County
of York, Engineer, and THOMAS HOLEHOUSE, of 70 Sunnyside, Chorlton-cum-
Hardy, near Manchester, in the County of Lancaster, 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 for improvements in and appertaining to the valve gear of duplex
direct acting engines, relates to certain improvements in the arrangement of, and
mechanism for actuating and controlling the valves of such engines, which said
valves are worked by means of levers having a compound positive motion for the
purpose of working the steam expansively, and our improvements consist, firstly, of
the addition of a cut off valve of the slide, Corliss or other type, the lap or travel of
which is capable of variation so as to regulate the expansion within any range;
secondly, of means whereby the length and ratio of the actuating levers may be
regulated to vary the expansion with an ordinary slide or circular valve, thirdly, of
means whereby a certain amount of slack or waste motion is provided for between
the coupling of the actuating levers and the valves, or in other words means
whereby some portion of the motion of the actuating levers is not imparted to the
valves, which said arrangement with a proportional amount of lap taken off the
valves, has the effect of lessening the expansion, and the steam can be carried on to
the full length of the stroke if desired, and further enables a duplex direct acting
engine with valves worked by levers having a compound positive motion to be
worked at a low piston speed, which has not heretofore been the case, fourthly of
means whereby a duplex direct acting engine working expansively by means of
levers having a compound positive motion, may be started immediately and without
trouble, which has not heretofore been the case.
In order to fully explain our invention we append hereto sheets of drawings
marked with letters of reference, of which-
Fig. 1 illustrates the first part of our invention, and is a side elevation of a duplex
direct acting engine for working a duplex pump, the valves and cylinder on the near
side being shown in section ;
Fig. 2 is a plan, and
Fig. 3 an end view of same, or a cross section through the piston rods between
the engine and pump.
Figs. 4, 5, and 6 illustrate the second part of our invention.
Fig. 4 being a side view of the valve gear arranged so that the length and ratio
of the actuating levers may be regulated.
Fig. 5 is a plan, and
Fig. 6 is an end view of same, the cross-heads being taken in section on
lines a-band c-d respectively.
In all the figures like letters denote like parts.
The letter A designates the near cylinder, and the letter A' the far cylinder of a
duplex direct acting engine for working a duplex pump, the pistons of which move
approximately in relation to each other as if connected to cranks at right angles,
and so connected as to act reciprocally upon the admission valves of each other.
The gear for actuating the main valves being identical in the case of both cylinders
the same letters of reference are used to designate these identical parts, but the
addition of a 1 to a letter denotes that the part works or operates the valve of the
far cylinder A' In describing the gear for actuating the cut off valve this does

page_text: .
not apply, as the lever or levers which actuate the main slide valve of the far
cylinder may also actuate the cut off plate of the near cylinder or vice versa.
B and B are the piston rods.to which are attached crossheads C and C¹. These
crossheads are fitted with oscillating sleeve like blocks to receive the ends of
levers D and D', and E and E', for actuating the valve rods F and F', within
which blocks as the crossheads travel to and fro the levers have a sliding motion as
they oscillate on fixed centres as hereafter described. These levers impart to the
ordinary slide valve a compound positive motion which is effected as follows.
Taking the motion of the levers connected with the valve of the near cylinder A,
the lever D actuated by the crosshead of the far cylinder A' oscillates on the centre
of a pin G to which it is attached, the pin G being carried by a fixing or bracket H,
and to which pin is attached a short lever or link J. The lever E actuated by the
crosshead C, oscillates on a pin or stud K attached to the short lever or link J, and
thus to the upper portion of the lever E designated by the letter L a compound
motion is given or communicated to the valve rod F by means of any suitable
coupling arrangement. In connection with the far cylinder A identically the same
arrangement is adopted for actuating the valve rod F¹. The lever D' actuated by
the crosshead C oscillates on the centre of the pin G³ carried by a bracket H', and
lever E actuated by crosshead C¹ and oscillating on pin K' is coupled to lever D'
by the short lever or link J', motion being given to the valve rod F by coupling
up to the portion of the lever E' marked L. Having described means whereby we
impart motion to the main valves, we will now proceed to set forth means for
working cut off valves in connection therewith, which said cut off valves may be
cut off plates as shown in Fig. 1, a single cut off plate or a cut off valve off the
Gorliss or other type. The valve rods of the cut off plate are marked M and M'
respectively, and in the case of the near cylinder A, we can work the valve rod M
from its own crosshead C by a continuation of the lever D' beyond its fulcrum,
such portion being marked N and which imparts to the valve rod a motion contrary
to the crosshead, and is coupled to the valve spindle by any well known means.
the case of the cut off valve of the far cylinder A', we attach to the crosshead C¹
an additional lever D2 oscillating on a pin carried by a suitable fixing or bracket,
the centre on which this lever oscillates, or fulcrum of the lever, being about the
same distance from the centre line of the engine as in the case of the lever D' on
the opposite side, so that the ratio of the levers for actuating the valve rods of the
cut off valve is in both cases identical or thereabouts. In some cases the expansion
. valve may be worked from a continuation of the levers, or links J and J', or the
valves may be actuated by rocking levers to which motion is imparted by any of
the levers named for working the main slide valve, the exact means of coupling to,
or actuating the valve rods M and M by their respective crossheads, being regulated
by the special conditions under which the engine may have to work. In order to
vary the expansion of the steam or other fluid in the cylinders within any range, the
cut off valve may be of the variable expansion type regulated by hand, the cut off
valve shown in Fig. 1 being of the well known Meyer type. In case of the cut off
valves being of the Corliss type the expansion may be varied by lengthning or
shortaing the valve coupling rods. Another method of varying the expansion by
lengthning or shortning the stroke of the valve rod by increasing or decreasing the
distance between the centre of the pin to which the valve rod is attached, and the
centre of the fulcrum upon which the actuating lever oscillates. Such an arrange-.
ment is shown in side elevation in Fig. 7.
In
The lever N is slotted for the reception of a sliding block O to which block the
valve rod M is attached. The block O forms a nut for a screw O' and by the
rotation of the latter by means of a hand wheel the sliding block O is raised or
lowered, and the length of the travel imparted to the valve rod M thereby varied
as may be desired.
In reference to the second part of our invention which is illustrated in Figs. 4,
5, and 6, the same mechanism of levers is adopted for actuating the valve rods F
and F1 as previously described, but means are applied whereby the ratio of the

page_text: length of the actuating levers may be varied independently of one another, and
for this purpose the crossheads C and C' are provided with slots for the reception
of moveable or sliding oscillating blocks a and a', which may be raised or lowered
by screws and b', fitted with hand wheels, the blocks a and a¹ forming sleeves
for the reception of the extremities of the actuating levers D and D¹ so that as
the blocks are raised or lowered on the levers the point of application of motion
supplied by the reciprocating crossheads is brought nearer to, or further from
the fulcrum, and the resultant distance of motion beyond the fulcrum thereby
diminished or increased.
The levers E and E are similarly attached to their respective crossheads C
and C', for which slots c and care provided, and fitted with sliding blocks d
and d which may be secured in any desired position in their respective slots
by nuts.
The third part of our invention consisting of an arrangement of parts whereby
with a certain amount of slack or lost action provided for between the coupling
from the actuating levers and the valves, and with a proportionate amount of lap
taken off the valve, steam is thereby enabled to be carried to the full length of
the stroke if desired, and an expansive duplex direct acting engine converted into
a non expansive one. This arrangement is shown in side elevation in Fig. 8, and
consists of fitting on to the valve spindle crosshead e a block f which has a certain
amount of longitudinal play therein as shown by the space e¹. To the block f the
valve spindle is attached, also the valve rod F coupled at its other end to the
actuating lever. In operation it will be obvious that before the valve is moved in
either direction, the block will have been moved a distance equal to the amount
of longitudinal play provided in the crosshead e.
The fourth part of our invention, consisting of means for starting an expansive
duplex direct acting engine, is shown in Figs. 1, 2 and 3 and other arrangements
for the same purpose in Figs. 9, 10, and 11. The arrangement shown in Figs. 1, 2,
and 3 consists of the provision of steam valves g and g' to admit steam directly
into the steam cylinders either from the steam chests or steam pipes. These valves
have no connection with, and are entirely distinct from the steam distribution
valves, and are only required in the case of a duplex direct acting engine working
expansively. Another arrangement shown in Fig. 9 which is a side elevation of
same and consists of the arrangement of parts for providing a certain amount of
slack action between the actuating levers and the main valves as previously
described, but with the addition of means whereby this slack action is arrested
immediately the engine has got away.
The block in the crosshead is prepared with a hole or depression into which
fits a spring actuated catch s holding the block f in a fixed position in the
crosshead.
At such times as it may be desired to start the engine, the catch g is withdrawn
from the block by means of a manual lever, which enables the engine to get
away, after which the slack action is immediately arrested by the spring causing
the catch to secure the block in its proper position again.
A third arrangement for this purpose consisting of means whereby the centre or
fulcrum on which the levers D'and D' oscillate is manually moved horizontally,
and the valve thereby opened is shown in Figs. 10 and 11, Fig. 10 being a side
view and Fig. 11 an end view of such an arrangement applied to the near cylinder
valve, which we carry out as follows. On the frame of the engine we fix two
brackets or supports i carrying a lever k, forked, or otherwise prepared at its lower
end to engage with a pin l so that by manually drawing the same in the direction
of the arrow, the bracket H carrying the pin G, which is the centre or fulcrum_on
which the lever D oscillates, is moved horizontally and the position of the valve
thereby altered, whereby the steam or other fluid is admitted to the cylinder and
the starting of the engine thereby effected. For this purpose the bracket H is
prepared to slide in the frame, and further is brought back to its normal position
upon the manual lever & being released, by means of the coiled spring m.

page_text: 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-
Firstly. In a duplex direct acting engine provided with an arrangement of valve
gear and levers having a compound positive motion, worked from the steam piston
rods for actuating the main steam valves, the application thereto of a steam cut off
valve worked by means of said levers or by independent levers, actuated from the
steam piston rods, substantially in the manner as shown and described.
Secondly. In a duplex direct acting engine as above described, the variation of
the ratio of the actuating levers whereby the cut off valve thereto applied may
be varied in its travel to give increase or decrease of expansion in the steam
cylinders, substantially in the manner as shown and described.
Thirdly. In a duplex direct acting engine having a single steam distribution
valve, and provided with valve gear and levers having a compound positive motion
worked from the steam piston rods for actuating the steam valves, the variation of
the length and ratio of such actuating levers, by means of sliding blocks to give an
increase or decrease of expansion in the steam cylinders substantially in the manner
as shown and described.
Fourthly. In a duplex direct acting engine having a single steam distribution
valve, and provided with valve gear and levers having a compound positive motion
worked from the steam piston rods, the provision of a certain amount of slack
action between the actuating levers and the coupling to the valves, substantially in
the manner as shown and described and for the purpose herein set forth.
Fifthly. In a duplex direct acting engine having single steam distribution
valves, or arrangement of main and cut off distribution valves, and provided with
valve gear and levers having a compound positive motion worked from the piston
rods, for actuating the said valves, the addition of a valve or valves connected
directly from the steam chest or steam pipes to the cylinder or cylinders, for the
purpose of starting such engine, substantially in the manner as shown and
described.
Sixthly. In a duplex direct acting engine having single steam distribution valves,
or arrangement of main and cut off distribution valves, and provided with valve
gear and levers having a compound positive motion worked from the piston rods
for actuating said valves, the provision of a slack action between the actuating
levers and the main valve or valves to be brought into operation for the purpose of
starting such engine, substantially in the manner as shown and described.
Seventhly. In a duplex direct acting engine having single steam distribution
valves, or arrangement of main and cut off distribution valves, and provided with
valve gear having a compound positive motion worked from the piston rods for
actuating said. valves, the horizontally moveable fulcrum pin G actuated by
manual lever K, for the purpose of starting such engine, substantially in the
manner as shown and described.
Dated this 25th day of Anril 1902
I. SIDNEY CRITCHLEY,
Agent for the Applicants.