ments in duplex Steam Engines
Year: 1889

page_text: Engines.
I ALFRED GEORGE BROOKES of the Firm of William Brookes and Son of 55 and 56
Chancery Lane in the County of Middlesex Fellow of the Institute of Patent Agents
(a communication from abroad by Charles Campbell Worthington of Irvington,
in the State of New York, United States of America, Engineer) do hereby declare the
nature of this invention and in what manner the same is to be perforined, to be
particularly described and ascertained in and by the following statement :-
This Invention relates to improved means of actuating the cut off valves, that is the.
valves which cut off the supply of steam to the cylinders and the suppression valves
which are described in the Specification of Letters Patent granted to me the said
Alfred George Brooks on the 28th day of November 1887 No. 16326 for "Improve-
ments in duplex Steam Engines," that is the valves which suppress the escape of the.
exhaust steam from the cylinders, of direct acting pumping engines whether compound.
or single cylinder, both of the ordinary duplex type and of the Worthington high
duty type fitted with compensating cylinders. These improved means enable the.
admission and suppression of the steam to be controlled with great accuracy. Further
the improved main steam slide valves are fitted with cut off valves working directly.
on the top of the main valves and suppression valves either a D valve working
directly on the top of the main valve or Corliss valves working directly on the inside of
the main valve.
For whereas, in the ordinary method of driving the valves of direct acting duplex
pumping engines the main valves of the one engine receive the motion of the steam
pistons of the other engine on a reduced scale and the cut off and suppression valves
receive the motion of the steam pistons of their own engine on a reduced scale, if the
cut off and suppression valves are placed so as to work directly on or in the main.
valve, it is impossible to determine the exact point of cut off and suppression as the
main valve is shifting with the pistons of the other engine and it is necessary to intro-.
duce a fixed plate for the cut off and suppression valves to work on, which fixed plate
necessitates either extra steam clearance space in the ports or extra friction and extra.
chance of steam leakage. I overcome these objections by the introduction of a floating

page_text: lever' for driving the. cut off and suppression valves, which floating lever transmits to
the cut off and suppression valves the combined motions of the steam pistons of both
engines on a reduced scale and in such a manner that the point at which the cut off
and suppression valves close and open when working directly on or in the main valve
is not affected by the position of the main valve, as, whatever movement the main valve
receives from the opposite,engine, the cut off and suppression valves, or, in the case
when the Corliss suppression valves are used, the pins in the levers keyed to the Corliss
valve spindles, receive the same movement both in amount and direction.
Figures 1, 2, 3, 4, 5, 11 and 12 show the invention applied to a compound direct
acting duplex pumping engine.
'
Figure 1 is a longitudinal section through the cylinders of one engine.
Figure 2 is a plan of the four cylinders and valve gear.
Figure 3 is a cross section.
Figure 4 is a longitudinal section on the suppression valve spindles p¹ and p².
Figure 5 is a longitudinal section on the lino A. A.
Figures 11 and 12 show the main valve g' of Figure 1 with the cut off and suppression
valves in longitudinal and cross section to an enlarged scale.
The same letters of reference are used to denote corresponding parts in the various
figures.
The letters referring to parts of the left hand engine are distinguished by a
the letters to the corresponding parts of the right hand engine.
* from
The eccentric discs d. d. shown in Figure 1 and to an enlarged scale in longitudinal
and cross section in figures 13 and 14 receive a rocking motion about the centre of the
shaft e, to which they are keyed from the piston rod * or from some other convenient
point moving with the piston rod k* of the other engine, the motion being transmitted
to the shaft e through the levers a*, *, and c, and the main valves g₁g, receive their
motion from a pin f, in the discs d, d, the pin fbeing connected by a link to crosshead u.
on the spindle to which main valves are attached.
The eccentric straps h, h shown in figure 1 and to an enlarged scale in figures 13 and
14, loose on the discs d, d, form the floating lever which drives the cut off valves 1, 2,
and the suppression valves n₁, n₁, n, n by the pin i connected by a link to cross
head von spindle m₁. In this arrangement the loss motion head z. shown in figures 13
and 14 is not employed but an ordinary eye similar to that on pin j.
The cut off valves a₁₁, are throaded on the spindles m₁, m, which are screwed
with right and left handed threads and driven from the pin i-the desired point of
cut off being obtained in the usual manner by revolving the screwed spindles m₁ ma
about their axes and so shifting the cut off valves.
The suppression valves n₁ n nn, are driven from a cross head on the spindles m₁, ma
through levers keyed on the rock shaft o giving the spindles pi P: the same movement
as the spindles my ma.
The cross heads 91, 92, 93, 94, are threaded on the spindles P1, P2, which are screwed
with right and left handed threads-these cross heads drive levers 71 72 73 ₁ keyed on
to the spindles 51 82 53 54 of the suppression valves as shown in figure 12 and the
spindle s₁ drives the suppression valves n₁ by a projecting cross piece t₁, which bears
against lugs on the end of the valve; the desired point of suppression is obtained by
revolving the screwed spindles P₁ P2 about their axes and so shifting the suppression
valves round.
The floating lever h. h is connected by the pin ; to the lever a which is driven from
the piston rod k or from some other convenient point moving with the piston rod k of
the same engine as the valves connected to pin i.
The floating lover h. h receives two movements, a rocking movement about the
centre of the disc d, d from the piston rod k through lever a, and pin j, which causes
pin i to open and close the cut off valves 1, 2, 3, 4 and suppression valves n₁, no,
na, n, and a rocking movement about pin j from the piston rod k*, by the rocking of
lever e. l. which imparts to crosshead by pin i the same movement both in amount
and direction as pin fimparts to cross head u.
I determine the position of the point l. in discs d d, so that the rocking of the

page_text: lever e. l, will give the crossheads u and v the same movement both in direction and
amount, as follows :—
When the lever j. i and discs d. d are in their middle positions the point 7 is in the
straight line jei and the travel of the point 7 is some multiple of the travel of the
pin dependent on the proportion of the lengths j. I and j. i of the floating lever h. h.
j.i
Therefore travel of
7
=
travel off.
and e. l
-
e. f.
u
The action of the floating lever is as follows.
=
Whatever movement the pin f driving the crosshead u. receives from the piston
rod the centre of the discs d d receives half that movement and rocks the floating
lever h. h about pin j as a fulcrum and as l: j j.. the pin imparts the same
movement both in amount and direction to crosshead vas pin fimparts to crosshead u.
Thus for any movement of the main valve alone the distances of the cutting off
edges of the cut off and suppression valves from the edges of the ports in the main
valve remain the same and the exact point of cut off and suppression can be determined
without reference to the position of the main valve and the distances of the cutting
off edges of the cut off and suppression valves from the edges of the ports in the main
valve are only altered either by the movement of the pin ; when j receives the motion
of the piston rod k on a reduced scale and causes the pin i to open and close the cut
off and suppression valves or by revolving the spindles m₁ m, P₁ Pz
The valves of the other engine are driven in a similar manner.
Again figs. 6, 7, 8 and 9 show the invention applied to a compound direct acting
duplex pumping engine, here the arrangement of the valve gear is somewhat different
and the pin is in the floating lever is placed between the points j and 1, but the valves
and cylinders are the same as in the example just described. Fig. 6 is a longitudinal
section through the cylinders of one engine.
Fig. 7 is a plan of the upper rock shafts and levers omitting the levers w, and w₁*.
Fig. 8 is a longitudinal section on line B. B.
Fig. 9 is a plan of the lower rock shafts and levers.
The lever d. receives a rocking motion about the centre of the shaft e, to which it
is keyed from the piston rod k* or from some other convenient point moving with the
piston rod of the other Engine, the motion being transmitted to the shaft e through
the levers a, b and c the crosshead u on the spindle to which the main valves 91, 92
are attached receives its motion from a pin fin lever dq.
The two flitches h. h form the floating lever which drives the cut off
valves 13 and the suppression valves n₁, na, na, n₁ by the pin i, and the.
levers w₁ and we which are of equal length, and the pin in connected by a link to
crosshead von spindle m₁.
One end of the floating lever h. h is loose on the pin
in lever d₁, which is driven

page_text: from the piston rod * and the other end is connected by the pin to the lever a,
which is driven by the lever a₁ from the piston rod k or from some other convenient
point moving with the piston rod k of the same engine as the valves connected to
pin i2.
The floating lever h. h.receives two movements, a rocking movement about the
pin in lever d, from the piston rod k by pin j through levers a₂ and a₁,
which causes
pin is driven from pin through levers ₁ and w₂ to open and close the cut off
valves,
and the suppression valves n₁, na, na, n, and a rocking movement
about pinj from the piston rod * by the rocking of the lever e. I which imparts to
crosshead driven from pin i, the same movement both in direction and amount as
pin fimparts to crosshead u. : f
で
I determine the position of the pin in lever d₁, so that the rocking of the lever e.l
will give the crossheads and the same movement both in direction and amount, as
follows: When the levers j. l and .e are in their middle positions the pin is in the
straight line je and the travel of the pin is some multiple of the travel of
pindependent on the proportion of the lengths j. I and j. ₁ of the floating lever h. h.
j.l
j. į
Therefore travel of
U
==
and e. 1
=
Q
22
×
travel off.
e. f.
The action of the floating lever is as follows.
Whatever movement the pin f driving the crosshead receives from the piston
rod the pin in the lever d₁ receives twice that movement and rocks the floating
lever h. about pin as a fulcrum and as 1. j = twice j₁, the pin imparts the same
movement both in direction and amount through levers w₁, w, and pin is to crosshead v
as pin fimparts to crosshead u.
Thus for any movement of the main valve alone the distances of the cutting off
edges of the cut off and suppression valves from the edges of the ports in the main
valve remain the same and the exact point of cut off and suppression can be
determined without reference to the position of the main valve, and the distances of
the cutting off edges of the cut off and suppression valves from the edges of the ports
in the main valve are only altered either by the movement of the pin when j
receives the motion of the piston rod k on a reduced scale and causes the pin i
to open and close the cut off and suppression valves or by revolving the
spindles m₁, ma, P1, P2,
The valves of the other engine are driven in a similar manner.
Again figs. 10, 13 and 14 show the invention applied to a compound direct acting
duplex pumping engine.
Fig. 10 is a longitudinal section through the cylinders of one engine, only the high
pressure cylinder is shown the valves on the other cylinder being similar.
Figs. 13 and 14 show the discs d, d, floating lever h. h, lost motion head and
block y in longitudinal and cross section.

page_text: Here the arrangement of the gear for driving the crossheads u and v connected
respectively to the main valves 91, 92 and the cut off and suppression D valves 1,
is the same as shown in figs. 1, 2, 3 and 5 with this exception that the pin i works in a
lost motion head z on the link driving the crosshead v.
The cut off and suppression valves are combined in the D valves ₁, 2 fixed by nuts
on the spindles m₁, me and working directly on the main valves 91, 92.
The desired point of cut off and suppression is obtained by adjusting the screwed
bolts in the block y and so increasing or diminishing the amount of lost motion.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I wish it to be under-
stood that I do not confine myself to the exact methods of construction shown on the
drawings as they may be modified to suit different circumstances, I declare that what
I claim is :.
1. Actuating the cut off and suppression valves of direct acting pumping engines
whether compound or single cylinder both of the ordinary duplex type and of the
high duty type such as are manufactured by "H. R. Worthington" of New York
fitted with compensating cylinders in such a manner by the introduction of a floating
lever that with cut off and suppression valves working directly on or in the main
valves the point of cut off and suppression can be determined without reference to
the position of the main valves substantially as described and illustrated.
2. Improved main steam slide valves fitted with cut off and suppression valves for
regulating the cut off and suppression of the steam and working directly on or in the
main valves substantially as described and illustrated.
Dated the 1st day of January 1889
WM. BROOKES & SON,
55 & 56, Chancery Lane, London,
Agents for the Applicant.