Improvements in Steam Engines.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Steam Engines.
ROBERT BRUCE SMITH 27 Liversidge Road Higher Tranmere Birkenhead
Engineer, do hereby declare the nature of this invention to be as follows:-
1
My said invention has for its object the improvement of steam engines, chiefly
those for propelling ships, to be effected by shortening the length of the engines
also by reducing weight, and giving better distribution of steam, minimising
vibration by the strains being more centralized, and providing for the manufacture
of this form of engine in quintuple or sextuple types, should an increase of steam
pressure render such multiples of cylinders necessary.
In carrying out my invention use three cylinders for the triple; the high
pressure intermediate pressure, and low pressure; but if I use two low pressure
cylinders of the same area as the one cylinder, then in this case for the triple
expansion engine I use four cylinders; and each cylinder through its piston rod and
connecting rod operates upon its own crank pin: In the quadruple expansion
engine I use four cylinders one high pressure, one first, & one second intermediate
cylinder, and one low pressure cylinder; in the quintuple I use five cylinders, one
high pressure cylinder, three intermediate cylinders and one low pressure cylinder;
lastly, in the sextuple expansion engine I use one high pressure cylinder, four inter-
mediate cylinders, and one low pressure cylinder; each cylinder of the various types,
having its own crank pin, upon the same crank shaft. In the case where it is not
advisable to make the low pressure, or final cylinder, in one, then I will arrange it
in two cylinders as described in the triple expansion engine.
The crank shafts for each type may be of any material, and may be built up of
a number of separate pieces, and shrunk together to form the complete crank shaft,
or they may be forgings, and machined to their final form.
The cylinders will be arranged in pairs above, or at any angle with the crank
shaft, the longitudinal distance between their centres being the half of the width of
the two crank pins on which they operate plus the width of the link which connects
the inner ends of the crank pins together, this link may be loose as described in my
paddle wheel engine Specification or it may be shruuk on, or made solid with, or as
good as solid with the crank pins in any suitable way: In the case of the triple
expansion engine with three cylinders, there will be one single cylinder, and one
pair of cylinders, the single cylinder, or the pair of cylinders, being arranged
together as I find may suit my purpose best; but the cylinder by its self will have
its own crank pin and crank forined in the crank shaft in the ordinary way, while
the pair of cylinders, will have their crank pins arranged as described above; and
if the arrangement of a single cylinder by itselt, may be desired in any of the other
types, they may be arranged in this way, or it may be desirable to arrange one or
more of the cylinders, above the others tandem form, in which case I will arrange
them as desired.
The three, four, five, or six cylinders will be arranged in any convenient way
over, or at any angle with the crank shaft, and I will arrange the sequence of the
cranks in their rotation as will best suit the distribution of the steam to the various
cylinders as for example I may drive two valves with one set of valve gear, or 1
may arrange one valve to distribute the steam to each pair of cylinders, or I may
make each cylinder with independent valves and gear.
I may also arrange to disconnect the steam from one or more of the cylinders

page_text: so as to work at low powers, when it is not desirable to work the engines at full
power.
Bed plates and framing of suitable form, will carry the crank shaft, and connect
it, and the cylinders together, and as the cylinders in a vertical, or angular
athwartship plane will be angled to each other at an angle sufficient to clear their
bodies, (the centre of the crank shaft being the apex of the angle) owing to the
shortness of the distance between the centres of their crank pins, those pins will be
fixed to each other at an angle of 90° minus the aforesaid angle between the
cylinders for engines with four and 6 cranks; and for engines of three cranks, the
two pins driven by the pair of cylinders will be fixed to each other at an angle of
not more than 120° minus the angle between the cylrs. so that they with the third
crank will divide the circle in such a manner that the pistons of all the three
cylinders will work as if the pins were set at angles of 120° to each other. For
engines of 5 cranks the angle between the crank pins will be such that the pistons
of all the five cylinders will work as if said pins were set at angles of 72° to each
other. In the engines with 6 cranks I may also arrange the pins to suit angles
of 60° to each other, or to any other angle near to the aforesaid angles which will
approximately produce the same results. Further by another combination I may
arrange the three cylinders of a triple expansion, or other engine, in a group, with
their pistons and rods each connecting with separate crank pins; as this type of
engine will have only two main bearings; the central pin will be connected with
webs or links to the ends of the two side pins, and they in turn connected with webs
to the crank shaft in the usual way, preferably I arrange the crank pins at angles
of 120° to each other. Also in some small engines it may be desirable to arrange
four cylinders in a group, each cylinder being directly connected to its own crank
pin. The crank shaft having four 4 crank pins; and only two main bearings to
the engine.
Dated this Eleventh day of January 1895.
ROBERT BRUCE SMITH,
Applicant.
ROBERT BRUCE SMITH, 27 Liversidge Road, Higher Tranmere, Birkenhead,
Cheshire, 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 :-
My said invention has for its object the improvement of steam engines, chiefly those
for propelling ships, to be effected by shortening the length of the engines, also
by reducing weight, minimising vibration by the strains being more centralized,
and providing for the manufacture of this form of engine in quintuple or sextuple
types, should an increase of steam pressure render such multiples of cylinders
necessary.
In carrying out my invention I arrange the three cylinders of a triple expansion
engine, or other engine, in a group above the crank shaft, each with their pistons,
rods, and connecting rods, engaging with its own crank pin: As this type of
multiple expansion engine will have only two main bearings, the central pin will
be connected with webs or links to the ends of the two side pins, and they in turn
connected with webs to the crank shaft in the usual way, preferably I arrange the
crank pins at angles of 120° to each other. In the quadruple expansion engine 1
use four cylinders, one high pressure, oue first, and one second intermediate
cylinder, and one low pressure cylinder. In the quintuple expansion engine I
use five cylinders, viz., one high pressure cylinder, three intermediate cylinders,

page_text: and one low pressure cylinder, lastly in the sextuple expansion engine, I use one
high pressure cylinder, four intermediate cylinders, and one low pressure cylinder,
each cylinder of the various types having its own crank pin upon the same crank
shaft, (with the exception of the quadruple which will have two of its cylinders
engaging with the central crank più). In the case where it is not advisable to
make the low pressure or final cylinder in one; then I will make it in two
cylinders of equal volume to the one.
The crank shafts for each type may be of any material, and may be built up
of a number of separate pieces, and shrunk on, or bolted together to form
the complete crank shaft, or they may be forgings, and machined to their final
form.
Also in some small engines, it may be desirable to arrange four cylinders in a
group, each cylinder being connected to its own crank pin: the crank shaft
having four crank pins, and only two main bearings to the engine.
Referring to the drawings.
Fig. 1. Fig. 2. Fig. 6. are respectively, front elevation, end elevation, and plan
of a triple expansion engine in which 1. is the high pressure cylinder, 2. the
intermediate cylinder, and 3 the low pressure cylinder, and each cylinder
through its own piston, rod, and connecting rod, engages with its own crank pin;
A, being the H. P. pin, C. the intermediate cylinder pin, and B. the low pressure
cylinder pin in the centre of the group, this central pin B. is connected with the
ends of the pins A and C, by webs or links D. and E. while the other ends of said
pins are in turn connected by webs F, and G, to the main shaft H. which is
supported by bearings J. and K. contained in the bed plate L; this bed plate
being held to the group of cylinders by framing consisting of columns in front,
and condenser M. with columns attached at the back, but in many cases it is
desirable to place the condenser separate from the main engines, in which case the
framing will consist of columns at both back and front; the air, and circulating
pumps N.
are shewn attached to the condenser and driven from the main engines,
but it is often desirable to work either one or both of these pumps by separate
engines, in which case the main engines will be arranged without them. O in
Fig. 4 is an auxiliary bearing to be fitted if thought necessary to give additional
stiffness to the crank shaft.
Fig. 3. Fig. 4. Fig. 5. are respectively, front elevation, end elevation, and plan
of a triple or quadruple expansion engine, in which for the triple, 1. is the high
pressure cylinder, 2. the intermediate cylinder, and 3. and 4. two low pressure
cylinders, being together equal in volume to the third cylinder of the triple
expansion engine, and these two said cylinders through their pistons, rods, and
connecting rods, together engage with the central crank pin B. while the high
pressure engages with crank pin A. and the intermediate pressure with crank
pin C.
In Figs. 3 and 4 the crank shaft H. is shewn constructed of pieces bolted
together, and is supported in bearings J. and K. contained in the bed plate L.
which is held to the cylinders by framing similar to that described, and shewn
for Figs. 1. 2. & 6.
For the quadruple expansion engine, 1. is the high pressure cylinder, 2 and 3
the intermediate pressure cylinders, and 4 the low pressure cylinder, and
cylinders 3, and 4, through their pistons, rods, and connecting rods together
engage with the central crank pin B. while the high pressure engages pin A. and
the first intermediate 2. with pin C. O. is an auxiliary bearing which may be
fitted if thought desirable.
Fig. 7. is a plan of a quintuple or sextuple expansion engine, in which for the
quintuple type, 1. is the high pressure cylinder, 2. 3. and 4. the first, second, and
third intermediate pressure cylinders, and 5 and 6. are two low pressure cylinders
of a total volume equal to that of the 5th cylinder of a quintuple engine.
For the sextuple, 1. is the high pressure cylinder, 2. 3. 4 and 5. are the first,
second, third, and fourth intermediate cylinders, and 6. is the low pressure

page_text: cylinder of full volume, each of these types of engines is arranged in two groups
of three cylinders, over two crank shafts, similar in construction to those shafts
already described, and shewn in Figs. 1 to 6, and each cylinder 1 to 6, through its
own piston, rod, and connecting rod, engages with its own crank pin, A. B. C,
a. b. C, and the framing is of a construction similar to that described for, and shown
in Figs. 1 to 6.
Having now particularly described, and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is.
1st. Triple, quadruple, quintuple and sextuple expansion engines, for propelling
ships, or for land purposes, substantially as described in the foregoing Specification,
and as shewn in the accompanying drawings.
2nd. The crank shafts for the aforesaid engines with their crank pins set at 120°
to each other, or at any other angle differing from 120°, which shall promote the
smooth running of the engines, as described in the foregoing Specification, and as
shewn in the accompanying drawings.
3rd. The crank shaft for a four cylinder engine, having four crank pins
arranged in pairs placed at or about 90° to each other, and each pin of the pairs
placed at or about 180° to the other, supported by two main bearings, and with
or without an auxiliary bearing, as described in the foregoing Specification.
Dated this 9th day of November 1895.
ROBERT BRUCE SMITH,
Applicant.