IMPROVEMENTS IN CYLINDERS FOR ENGINES AND PUMPS
Year: 1884

page_text: We THOMAS WILLDIGG, of the Vulcan Works, Burges Coventry, in the County
of Warwick, Engineer, and WILLIAM JOHN BRETT, of 77 Lower Ford Street, of
the same Place and County, Engineer, do hereby declare the nature of our
Invention for "IMPROVEMENTS IN CYLINDERS FOR ENGINES AND PUMPS " to be as
follows:-
•
°
The object of this our Invention is to simplify the manufacture of cylinders in
which move pistons driven by fluid pressure.
Instead of forming a separate valve chest, or chamber, or chambers as is usually
done we provide two piston valves inside the cylinder itself, one at each end
thereof, these valves are for most purposes of the full diameter of the cylinder of
the engine. These piston valves-travel over two ports at either end of the cylinder,
the one port being for "live" steam to be admitted-to the cylinder and the other
for "exhaust" steam to be allowed to pass away from it. These two piston valves
are or may be connected together either by an attachment inside the cylinder
which attachment passes through the main piston of the engine or by attachment
outside the cylinder which are brought for that purpose outside and through the,
cylinder covers.
The two piston valves aforesaid are actuated by the main piston striķing against
them or by suitable provision on the main piston rod for the same purpose, undue
shock being avoided by the use of buffing springs of steel, vulcanized rubber or
other suitable material. The piston valves aforesaid have suitable openings where
required to allow exhaust steam to pass.
The ports in the cylinder are made somewhat in the usual way, wholly or partly
round the cylinder and with inlets thereto and one port in advance of the other.
The piston valves aforesaid have suitable openings provided in one or both as
requisite to allow the main piston rod or piston rods of the engine to pass
through.
For some purposes we make the piston valves of smaller diameter than the
main piston of the engine and in this case we, provide cylindrical recesses in the

page_text: cylinder covers and in these recesses the piston valves work, the steam and exhaust
ports being-arranged suitably.
"
In describing this our said Invention we have used the word "steam as we
should usually apply it to steam engines, but we do not limit its application to
steam engines, but instead of steam any other fluid capable of being used as a
prime mover may be employed as for example gas, compressed air or water.
We apply our invention to reciprocating engines chiefly, and to direct acting
pumps, to steam or other fluid driven hammers, rock drills, or other similar
machinery.

page_text: COMPLETE SPECIFICATION.
We THOMAS WILLDIGG of the Vulcan Works Burges Coventry in the County
of Warwick Engineer and WILLIAM JOHN BRETT of 77 Lower Ford Street of
the same place and County Engineer do hereby declare the nature of our
Invention for IMPROVEMENTS IN CYLINDERS FOR ENGINES AND PUMPS
what manner the same is be performed, to be particularly described and ascertained
in and by the following statement :—
" and in
The object of this our Invention is to simplify the manufacture of Cylinders in
which move pistons driven by fluid pressure.
Instead of forming a separate valve chest, or chamber or chambers as is usually
done we provide two piston valves inside the Cylinder itself one at each end
thereof, these valves are for most purposes of the full diameter of the cylinder of
the Engine These piston valves travel over two pts at either end of the cylinder
the one port being for "live" steam to be admitted to the Cylinder and the other
for "exhaust" steam to be allowed to pass away from it. These two Piston valves:
are or may be connected together either by an attachment inside the Cylinder
which attachment passes through the main piston of the Engine or by attachment
outside the Cylinder which are brought for that purpose outside and through the
Cylinder covers.
The two piston valves aforesaid are actuated by the main piston striking against
them or by suitable provision in the main piston rod for the same purpose, undue
shock being avoided by the use of the buffing springs of steel, vulcanized rubber or
other suitable material-The piston valves aforesaid have suitable openings where
required to allow exhaust steam to pass.
The Ports in the Cylinder are made somewhat in the usual way, wholly or
partly round the Cylinder and with inlets thereto and one port in advance of the
other The Piston Valves aforesaid have suitable openings provided in one or both.
as requisite to allow the main piston rod or piston rods of the Engine to pass.
through.
For some purposes we make the piston valves of smaller diameter than the
main piston of the Engine and in this case we provide cylindrical recesses in the
cylinders covers and in these recesses the piston valves work, the steam and exhaust
ports being arranged suitably.
"
In describing this our said Invention we have used the word " Steam as we
should usually apply it to Steam Engines, but we do not limit its application to
Steam Engines but instead of Steam any other fluid capable of being used as a
prime mover may be employed as for example Gas, compressed Air or Water.
We apply our Invention to reciprocating Engines chiefly, and to direct acting:
pumps, to steam or other fluid driven hammers, rock drills or other similar
machinery.

page_text: May
more Cically understood we
have prepared the accompanying sheet of drawings showing a Cylinder and its
accompanying parts constructed according to our Invention.
Fig 1. is a plan view.
Fig 2. is a longitudinal section.
Fig 3. is a transverse section on line W X looking towards V.
Fig 4. is a section through one of the piston valves on line Y Z shewing
apertures c³ c³.
Similar letters of reference denote similar parts in all the views in which they
occur.
a is the Cylinder having covers "a¹ a² one at each end b is the piston made in
any usual way and having the piston rod 6¹" secured to it, the piston b has the two
holes b' through it c and c¹ are the piston valves which control the admission cut
off and exhaustion of the Steam they fit the Cylinder a and are connected to each
other by the rods d d which pass through the holes 62 in the piston b The piston
valves c c are provided with "Springs "c² c² so that when pressed by the piston b
there may be no shock, they also have apertures c³ ³ in each to allow the steam to
pass through.
A Rod e is secured to one of the piston valves c² and passes out through one of
the Cylinder covers a this is moved to and fro when starting by the lever f which
has a handle f¹ at the end and a counter weight f-this lever f moves on the
fulcrum f. The steam enters at "g" and passes each way along the passage g¹
and through the steam ports g² g³ into the Cylinder a The exhaust steam leaves
the Cylinder through the exhaust ports h³ ³ and passing through the passage h¹
finds its way out by the outlet h.
The action of the mechanism is as follows, when the parts are in the position
shewn on drawing in Fig 2 the steam port g³ is closed by the piston valve "c"
and the steam port g2 is open, the steam enters the Cylinder a by this port and
forces the piston b to the left, in the direction of the arrow, at the same time the
steam which is on the left hand side of the piston b passes through the openings
c3 c in the piston valve c. as shewn also in Figs 3 and 4 and finds its way out
through the exhaust port h³ which is uncovered into the passage h' and through
the outlet "" into the atmosphere, during this time the exhaust port h2 at the
right hand end is closed by the piston valve c¹-When the piston 6 has advanced
far enough to the left, it strikes the springs c² c² on the piston valve c and when
sufficiently compressed to overcome their elasticity the piston valve c is moved to
the left The piston valve c¹ also moves to the left being connected with the valve-c-
-by-the-rod-dd-This movement closes the steam port g2 and the exhaust port h³
and opens the steam port g³ and the exhaust port h2-The incoming steam then
drives the piston b to the right, the steam at the right hand side of the piston then
escaping through the openings c³ in the piston valve c¹ and the exhaust port h²,
this movement continues till the piston strikes and compresses the springs on the
piston valve c³ when its movement is again reversed-When steam is first
admitted to the cylinder, the motion of the piston is or may be commenced by
moving the piston valves by hand by the lever f-In the Drawing the piston
valves are shewn as of the full size of the Cylinder a but they may be of different
size and work in suitable chambers or continuations of the Cylinder. The rods
connecting the piston valves may assume the form of a yoke outside the Cylinder
being connected to the piston valves by Rods passing through the Covers.
Instead of using the Spiral Springs on the valves we may use steam cushioning
in a way that is well known and which we also use to obviate the chance of the
piston valves striking the Cylinder covers.
Though in this Specification steam is mentioned as being employed yet we do
not coufine ourselves to its use but may use any other fluid, as air, Gas or water.
. We do not confine ourselves strictly to the form of ports as shewn on drawing
or herein before described but may modify them while not departing from our said

page_text: Invention for instance we may use ports in advance of the one of the other with
valves shaped to suit-We may actuate our piston valves when applied to the
rotative Engines by means of tappets or eccentrics.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is
1st In a Cylinder wherein works a piston impelled by fluid pressure the con-
struction of ports and passages in combination with piston valves as shewn
whereby we exhaust through different ports to those used for the live steam
thereby saving a certain amount of steam in each stroke.
2nd The construction and arrangement of the piston valves in the main cylinder
and moved by the main piston, these valves being connected to each other by
connections either within or outside the Cylinder.
3rd The construction and combination of parts as herein before described to
actuate the piston of a Steam pump, Steam Engine, Rock drill.or in other cases.
when a piston is impelled in alternate directions by fluid pressure.
D11