Improvements in Compound Steam Engines.
Year: 1894

page_text: Date of Application, 22nd Jan., 1894-Accepted, 24th Feb., 1894
Improvements in Compound Steam Engines.
We, WILLIAM HENRY ALLEN and RICHARD WILLIAM ALLEN both of York
Street Works Lambeth, London, S.E. Eugineers 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 object of our invention is to improve the construction of the distribution
valves and cylinders of compound or other expansive steam engines especially with
a view to economy in the consumption of steam. To do this we place the double
acting cylinders of a compound engine side by side and connect the reciprocating
pistons to the cranks by connecting rods in the usual way. The cranks may be
placed at an angle of 180° or any other suitable angle to one another.
We use a combination of piston valves with a flat D slide valve, the piston
valves distributing the steam to the high pressure cylinder and the flat D slide
valve distributing the steam for the large or low pressure cylinder. In a compound
engine as described above, we arrange all the valves between the cylinders and
preferably we use two piston valves of the ordinary piston type to distribute the
steam to the smaller cylinder; these valves are placed one on each side of the
centre line of the two cylinders. The piston valves take steam on their inside
edges and after the steam has performed its useful work on the high pressure
cylinder the valves on their outer edges uncover the port to exhaust, the escaping
steam passing direct into a receiver between both the cylinders. The D slide
valve regulates the distribution of steam to the low pressure cylinder only, the
exhaust steam from the smaller cylinder passing direct from the receiver to the low
pressure cylinder over the outer edge of the D valve; and the final exhaust steam
is controlled by the inner edge of this D valve while passing to the atmosphere or
condenser.
For compound engines having cranks at opposite angles these three or more
valves are connected together by a plate and are worked simultaneously by one
eccentric rod connected to a spindle working through one gland.
In cases where the cranks are coupled at 90°, we prefer to drive the valve for
each cylinder by separate eccentric rods.
Figure 1 is the vertical section of cylinders shewing arrangement of driving
gear for the distribution valves when the cranks are at 180º.
Figure 2 is the corresponding sectional plan.
Figure 3 is the vertical section of cylinders shewing arrangement of valves
and driving gear when the cranks are placed at 90°.
A is the valve spindle which is connected to bar B, passing through which are
the three valve spindles C, C, C. The high pressure valves H, H, are shewn in
correct position relatively to the piston. Steam enters the high pressure cylinder
by pipe F¹, passing through the ports F2, and exhausting through the same
ports F2 to the receiver D; from the receiver the steam passes into the low pressure
cylinder through the ports G, and it finally passes to the atmosphere through the
port J and exhaust pipe K.
In Figure 3, A and A³ are the two valve spindles for operating the separate
valves. The arrangement of. ports is exactly as described in figure.
Having now particularly described the nature of our invention, we declare that
what we claim is :
First. The construction and combination in a compound engine of a high pressure
a low pressure evlinder side by side. having two or more piston valves.for
and

page_text: distributing the steam in the smaller or high pressure cylinder, and one D slide
valve for distributing the steam in the low pressure cylinder, all three valves worked
simultaneously from one eccentric rod when the cranks of the engine are placed
at 180° as described and illustrated.
Secondly. The construction and combination in a compound engine of a high
pressure and low pressure cylinder side by side having two or more piston valves
for distributing the steam in the small or high pressure cylinder and one D slide
valve for distributing the steam to the low pressure cylinder, the high pressure
valves worked from one eccentric and the low pressure valve worked from another
eccentric when the cranks of the engine are placed at 90°, as described and
illustrated.
Dated this Nineteenth day of Januar 1804
W. H. ALLEN.
R. W. ALLEN.