IMPROVE- MENTS IN MARINE ENGINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Robert Wyllie at the
Office of the Commissioners of Patents on the 7th December 1883.
ROBERT WYLLIE, of West Hartlepool, in the County of Durham, "IMPROVE-
MENTS IN MARINE ENGINES
"
This Invention has for its object the arranging or combining together of the
parts of marine engines having two or more cylinders in an improved manner and
so as to economise space, the valve chests and valve gear, being disposed in a
convenient and simple manner, whilst easy access is provided to all the working
parts of the engines.
In carrying out the Invention in the case of triple-expansion engines with three
inverted cylinders for driving the screw propeller, the low-pressure cylinder is
placed between the high-pressure and intermediate cylinders, and the exhaust
steam being led down the back column thus enters the condenser at about the
middle of its length, the condenser being of the ordinary type with its tubes
horizontal and parallel to the crank shaft. The cylinders are placed as closely
together as their covers will admit of, and the valve casings are all at the sides.
The valve motions are of what is known as the fixed-link kind but with parts
arranged in a novel manner. A single eccentric is used for each valve, the actions
for reversing and for varying the cut-off being obtained by altering the oblique
position of the link or guide piece. The rod of the eccentric is arranged to act as
a lever with a moving fulcrum this fulcrum being formed by a pin on the lever
having jointed on it a slide block fitted to work on or within the link or guide piece.
This guide piece or link which may be constructed in various well known ways is
made with a trunnion or trunnions, or it is carried on a pin or stud at about its
middle point and is connected to a lever or hand wheel by means of which it can be
moved into whatever oblique position is suitable for the desired action of the
valves. The end of the eccentric lever or rod in consequence of being carried as
1

page_text: described moves in an approximately elliptic path, and from another pin or stud
suitably fixed on it the motion is transmitted for working the valve. The link or
guide piece is by preference placed so that the line from its centre to that of the
crank shaft is diagonal or oblique; it may however be placed in other positions
when the arrangement of other parts of the engines renders it desirable The pin
on the eccentric lever or rod is connected by a rod to a lever on a short rocking
shaft which has also on it a lever connected to the valve spindle.
The improved arrangements can be advantageously adopted with two-cylinder
compound engines, and with four-cylinder triple-expansion engines; and they can
also be employed in engines having two or more cylinders placed horizontally
in which case the valve casings will be placed on the upper sides of the
cylinders.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Robert Wyllie in the Patent Office on the 3rd June 1884.
ROBERT WYLLIE, of West Hartlepool, in the County of Durham, “IMPROVE-
MENTS IN MARINE ENGINES
"
My said Invention has for its object the arranging or combining together of the
parts of marine engines having two or more cylinders, in an improved manner,
and so as to econoinise space, the valve chests and valve gear being disposed in
a convenient and simple manner, whilst easy access is provided to all the working
parts of the engines.
In carrying out my Invention in the case of triple-expansion engines with three
inverted cylinders for driving the screw propeller, the low-pressure cylinder is
placed between the high-pressure and intermediate cylinders, and the exhaust
steam being led down the back column thus enters the condenser at about the
middle of its length, the condenser being of the ordinary type with its tubes
horizontal and parallel to the crank shaft. The cylinders are placed as closely
together as their covers will admit of, and the valve casings are all at the sides.
The valve motions are of what is known as the fixed-link kind, but with parts
arranged in a novel manner. A single eccentric is used for each valve, the actions
for reversing and for varying the cut-off being obtained by altering the oblique
position of the link or guide piece. The rod of the eccentric is arranged to act as
a lever with a moving fulcrum, this fulcrum reciprocating upon the guide piece,
which may be constructed in various well known ways and which is carried
so that it can be set in various inclined or oblique positions to suit the desired
actions of the valves. A stud suitably fixed on the eccentric rod and which stud
moves in an approximately elliptic path, has jointed to it a rod or link which
transmits the motion to the valve through a lever or rocking shaft. The link or
guide piece is by preference placed so that the line from its centre to that of the
crank shaft is diagonal or oblique; it may however be placed in other positions
when the arrangement of other parts of the engines renders it desirable.
My improved valve arrangements can be advantageously adopted with two-
cylinder compound engines, and with four-cylinder triple-expansion engines; and
they can also be employed in engines having two or more cylinders placed
horizontally, in which case the valve casings will be placed on the upper sides of
the cylinders.
An example of my improved arrangement of valve gear is shown on the
accompanying sheet of explanatory drawings. Figures, 1, and 2, are end and side
elevations showing one cylinder of a set of engines with inverted cylinders for
driving the screw propeller. In this example the valve casing, 6, is on the
opposite side of the cylinder, 7, from that which is above the condenser, 8.
Figure, 3, is a diagram of an example in which the valve casing, 6, is above the
condenser, 8. Figures, 4, and 5, are enlarged views showing one of the various
modes in which the moving fulcrum of the eccentric rod may be arranged.
In the example delineated in figures 1 and 2, the "fixed link" or guide piece, 9,
consists of a pair of parallel bars, connected so as to act as one piece, being formed
with trunnions, 10, on their outer sides to rest and turn in bearings in blocks, 11,
fixed to the top of the condenser, 8. The upper ends of the guide bars, 9, are
slotted to receive a transverse pin, which serves for connecting them, and also as a
joint pin for connecting to them a link, 12, by means of which they are placed in
different inclined positions as required for going ahead or astern or for varying the
cut-off, this link, 12, being connected to any suitable handing or starting lever or
gearing. The connecting pin can be adjusted and fixed in different positions in

page_text: the slots of the guide bars, 9, so as to give different degrees of inclination of the
bars for a given movement of the link, 12. Between the guide bars, 9, there is
fitted so as to slide on them, a double saddle piece or slide, 13, consisting of two
parts formed in one piece with a transverse pin, 14-and on this pin, 14, is
jointed the end of the eccentric rod, 15, in the manner plainly shown in figures, 4,
and 5. The connection of the eccentric rod, 15, with the "fixed link or guide
piece, 9, may be made in any other convenient way.
A
The eccentric rod, 15, is connected by a rod or link, 16, to a lever piece, 17, 18,
which is carried on a stud, 19, fixed to the framing, and which has its lever
arms, 17, 18, formed obliquely so that whilst the end of one, 17, to which the
rod, 16, is connected is in the vertical plane of the eccentric, the end of the
other, 18, is in the vertical plane of the valve rod, 20, to which it is connected.
vertical plane passing through the two ends, 17, 18, of the lever piece cuts the
middle of the bearing or nearly so, an arrangement which prevents any undesirable
strains from being caused by the obliquity of the lever arms, 17, 18. Instead of
this arrangement of an oblique lever piece on a stud, a rocking shaft may be used,
such shaft being carried in suitable bearings and having separate levers fixed on it.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described or delineated but that what I believe to be novel and
original and claim as the Invention secured to me by and in terms of the
hereinbefore in part recited Letters Patent is :-
1. The arrangement of triple-expansion marine engines in which the low-pressure
cylinder is placed between the high-pressure and intermediate cylinders as
herein before described.
2. The mode of arranging "fixed-link" valve gear (or valve gear with which the
movement of the valve is mainly derived from the transverse or swinging
movement of the eccentric rod) in combination with other parts of marine engines
substantially as hereinbefore described.
In Witness whereof, I, the said Robert Wyllie, have hereunto set my hand
and seal this thirtieth day of May in the year of our Lord One thousand eight
hundred and eighty-four.