Year: 1887

page_text: Date of Application, 28th Nov., 1887
Complete Left, 30th May, 1888
Complete Accepted, 6th July, 1888
in the State of New York, United States of America, Engineer.
I ALFRED GEORGE BROOKES of the firm of Wm. Brookes & Son of 55 & 56
Chancery Lane in the County of Middlesex, Fellow of the Institute of Patent Agents,
do hereby declare the nature of this invention to be as follows:-
The object of this Invention is to provide a suitable means of obtaining compression
or a cushioning of the exhaust steam in Duplex and Worthington Engines without
interfering with the position of the main exhaust valve, or putting inside lap on it
so that it opens to exhaust at exactly the same position as if the compression valves
were not fitted. The present means of arresting the motion of the piston at the end
of the stroke is by making two ports at each end of the cylinder, so that compression
is produced by over running one of the ports. This means is effectual but the point
of compression cannot be varied and it necessitates double ports and large clearance
spaces.
By this invention only one port is required and the compression valve can be closed
at any point of the stroke suitable to the amount required. It consists in putting
two separate supplementary exhaust or compression valves in the course of the steam
to the exhaust, these valves being each closed by the motion of its own piston at each
end of the cylinder, the main valve which admits steam and opens exhaust being
moved by the sister Engine as is usual in Duplex or Worthington Engines. These
compression valves are placed by preference between the main exhaust passage and

page_text: the main exhaust valves or they may be placed in the main valves themselves. These
valves are easily driven by the direct motion of the Engine. Their point of closing is
adjustable by hand while the Engine is running, by this means the steam distribution
is rendered complete the points of admission and exhaust being retained as heretofore,
namely, governed by the sister Engine while the compression valves are controlled by
their own Engine.

page_text: :
Improvements in Duplex Steam Engines.
A communication from abroad by CHARLES CAMPBELL WORTHINGTON, of Irvington,
in the State of New York, United States of America, Engineer.
I, ALFRED GEORGE BROOKES of the firm of Wm. Brookes & Son of 55 & 56
Chancery Lane in the County of Middlesex, Fellow of the Institute of Patent Agents
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:
The steam distribution in Worthington or Duplex Pumping Engines is effected
ordinarily by means of a slide valve having an exhaust cavity in its centre, this valve
having neither steam nor exhaust lap, the necessary motion being imparted to it by
the crosshead of the sister engine; but in place of the one port usually provided at each
end of the cylinder which serves for the admission of the steam into the cylinder and
its emission after it has performed its work in moving the piston two distinct ports
are usually formed at each end of each cylinder through one of which the steain is
admitted and through the other of which it is released from the cylinder either into
the atmosphere if the Engine is working non-condensing, or into the condenser if
condensing, or into another cylinder, if the Engine is worked on the compound, triple
or multiple cylinder system.
The ports for admitting the steam are always placed nearest to the cylinder covers
and the ports for exhausting the steam always nearest to the centre of the cylinder.
It is evident from this description of the position of these ports that the motion of
the piston is finally arrested after it has passed over the exhaust port, by compressing
the steam remaining in the steam port, as well as that contained between the face of
the piston and the cylinder cover. This arrangement while attaining the desired
object, has the disadvantage of necessitating the use of unnecessarily large clearance
volumes as well as large surfaces which are uselessly heated and cooled.
The object of this invention is to provide a suitable means of obtaining compression
or cushioning of the exhaust steam in Worthington or Duplex pumping engines,
without interfering with the position of the main exhaust valve, or putting inside lap
on it so that it opens to exhaust at exactly the same position, as if the suppression
valves were not fitted..

page_text: Figure 3 shows a plan of the cylinders and steam chests of a pair of Worthington or
Duplex Pumping Engines, Figure 4 shows a cross section of one of the suppression
valves to a larger scale than the one shown on Figure 2, and Figure 5 shows a longi-
tudinal section through the suppression valve to a smaller scale than Figure 4. The
same reference numbers in each of the figures to the same parts. In Figures 1 and 3,
1. 1. 1. show the steam cylinders. 2. 2. the steam chests. 3. 3. 3. 3. the steam chest
covers 4 and 4 in Figure 2 the steam valves as ordinarily arranged (two valves being
merely used as a matter of convenience so as to shorten the steam ports and obviate
the necessity for using one very long valve), 5.5.5.5 in Figures 2. and 5 shew the
suppression valves for regulating the flow of the exhaust out of the end of the
cylinder. The main steam valves 4. 4 Figure 2 are worked from the cross-head of
the Sister Engine, in the manner usual in such Duplex pumping Engines, by means
of the valve rods 6. 6. Figures 1 and 2 and the suppression valves 5. 5. Figures 24
and 5 are worked from their own Engine by means of levers 7. 7. 7. 7. Figure 1,
and 7. 7 Figure 5, actuated by rods 8. 8. 8. Figures 1 and 3, and the bell
cranks 9. 9. 9. Figures 1 and 3 and the levers 10 Figure 1. It is of course obvious
that the suppression valves may be placed inside the main valves where it is more
convenient to do so and that the termination of admission of the steam to the cylinder
may be effected by means of a cut off valve on the back of the main valve where it is
desired to let the steam expand in the cylinder. The point of closing of the suppres-
sion valves may be altered even while the Engine is at work by turning the right and
left handed screws 11. 11. Figure 1. which connect the ends of the levers 7. 7. 7. 7 Fig. 1.
communicating motion to the suppression valves.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is
I. In Worthington or Duplex pumping Engines whether single or multiple cylinder
the use of separate suppression valves, for closing the exhaust before the end of the stroke
such suppression valves to be applied to one or more of the cylinders, of Engines of
the Duplex type as may be found necessary in practice substantially as set forth.
II. In a Worthington or Duplex pumping Engine the combination of the Main
Steam Valve driven by the sister Engine, with the suppression valve driven by its
own Engine substantially as set forth.
III. Controlling the point of closing of the suppression valves in order to put com-
pression on the clearance for the purpose of warming up the surfaces of the clearance
spaces before the fresh steam is admitted thus reducing the amount of initial conden-
sation substantially as set forth.
IV. The use of suppression valves for the purpose of closing the exhaust before the
piston arrives at the end of its stroke and the pause takes place in order to prevent
the cooling action of the exhaust during that part of the pause when the cooling
action of the condenser is acting on the clearance and port spaces substantially as set
forth.