Engines.
Year: 1885

page_text: Engines.
I, JAMES CONSTHOPE PEACHE of Thames Ditton in the County of Surrey
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 :-
The Invention relates to means for reversing the engine; this is effected by
altering the position of the valve pistons relatively to that of the eccentric or other
source of motion so as to change the edge by which steam or other fluid is admitted
to or exhausted from the cylinder.
In the accompanying drawings Figure 1 is a vertical section of a Willans engine
with my improvements applied and with the valves set for forward motion.
Figure 2 is a vertical section of the same engine with the valves set for reversed
motion.
Figure 3 shows the valves in a modified form.
Referring more especially to Figures 1 and 2 it will be seen that the line of
piston valves can be raised or lowered relatively to the eccentric by means of the
screw at H, and the steam or other fluid will in one case be admitted into the
cylinder by. the upper edge of piston G uncovering ports D and in the other case
be admitted by the lower edge of piston F uncovering ports C. But I will describe
the arrangement more in detail:-N N N is the hollow piston rod in which the
line of piston valves work. C, D and E, are three rows of ports formed in the
hollow piston rod.
P is the main piston K the guide piston or cross head-Q the crank shaft, M the
crank pin, R the eccentric.
The upper portion of the valve piston rod I I is square and is free to move up
and down in a sleeve J J but cannot turn round in it. On the lower end of the
valve piston rod at H a screw is formed which screws into the valve piston guide
or cross head O. By turning round the sleeve J the line of pistons can be raised or
lowered relatively to the cross head O, and eccentric R.
When the valves are in a position shown in Figure 1 the engine will move in
direction shown by an arrow and when the valves are in the position shown in
Figure 2 the engine will move in reverse direction.

page_text: Thus in Figure 1 steam or other fluid is supplied at A and enters through ports
C and D into the cylinder until cut off by ports C passing down through the
stuffing box.
As the piston gets to the bottom of the stroke the lower edge of the valve
piston G uncovers the port D and allows fluid to escape during most of up stroke.
Just before the piston reaches the top of its stroke the upper edge of the valve
piston G uncovers port D and admits steam to the cylinder.
In Figure 2 steam or other fluid is admitted by ports C and D to the cylinder
until the port C passes down through the stuffing box. As the piston gets to the
bottom of its stroke the upper edge of the valve piston G uncovers port E and
allows steam to escape during mest of the up stroke. Just before the piston reaches
the top of its stroke the lower edge of valve F uncovers port C and admits steam
to the cylinder.
If it is desired to get an equal distribution of steam for both forward and
backward motions the angle formed by the centres of shaft crank pin and eccentric
should be a right angle but I prefer where the engine is usually required to run in
one direction to set the eccentric with an angle of advance for that direction of
motion so as to get a better distribution of steam for that direction of motion than
could be obtained from an eccentric having no angle of advance-and consequently
to get a less desirable distribution of steam for the reverse direction of motion but
still sufficiently good for occasional use.
My invention applies equally to engines in which the motion of the valves is
obtained from the angular motion of the connecting rod.
I do not bind myself to any particular arrangement of valves for instance the
valves may be arranged as shown in Figure 3 where X and Y are two piston valves
with holes through them, in a vertical direction and C and E are always used as
admission and exhaust ports respectively.
My invention is equally applicable to tandem compound engines of the central
valve type, a similar set of valves and ports being provided for the second
cylinder.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. Engines in which the valve working in a hollow piston rod or valve case
within the cylinder uncovers ports in the side of the said piston rod or valve case and
in which the connection between the valve and the eccentric or actuating part is
capable of being varied in such manner as to change the edge of the valve by which
steam or other fluid is admitted to or exhausted from the cylinder and at the same
time the direction of movement of the engine.
2. My improved arrangement of valves for Willans and other central valve
engines substantially as described and represented by the annexed drawings.
Dated this 23rd day of November 1885.
CARPMAEL & Co.,
Agents for the Applicant.