Improvements in Compound and Multiple Expansion Steam Engines.
Year: 1893

page_text: Date of Application, 5th Oct., 1893
Complete Specification Left, 2nd Aug., 1994-Accepted, 22nd Sept., 1594
PROVISIONAL SPECIFICATION.
Improvements in Compound and Multiple Expansion Steam Engines.
We, GEORGE EDWARD BELLISS and ALFRED MORCOM, members of the
Firm of G. E. Belliss and Company Limited, of Ledsam Street Works, in the
City of Birmingham, Engineers, do hereby declare the nature of this invention to
be as follows:-
Our invention relates to compound and multiple expansion steam engines and it
is principally applicable to three crank engines of either the compound or the triple
expansion type.
Our object is to produce a compound, a triple expansion, or a multiple expansion
engine in which the high and low pressure engines or the high, intermediate, and
low pressure engines are so disposed with reference to each other as to perfectly
balance the moving parts so that each reciprocating part is perfectly balanced by
the opposite motion of another reciprocating part or parts and each rotating or
partly rotating and partly reciprocating part is perfectly balanced by a movement
of a similar and similarly but oppositely moving part or parts.
Our object is also to minimise the pressure on the main bearings by a particular
disposition of the high and low pressure engine.
At the same time we so arrange our valve, steam ports and passages as to secure
the greatest simplicity of valve action, complete balance of valve parts and effective
steam distribution.
Our invention thus consists in a combination of engines arranged to obtain a
perfect balance and further in a novel and simple system of steam distribution
involving the use of the minimum number of valves and eccentrics.
In carrying our invention into effect as applied to a three cylinder compound
engine we arrange the high pressure cylinder between two low pressure cylinders
and we connect the two low pressure pistons to separate cranks on a crank shaft.
The low pressure crank centres coincide with each other.
We connect the high pressure piston to a crank directly opposed to the low
pressure cranks. The two low pressure pistons thus move to and fro precisely
together and the high pressure piston between them always moves in the opposite
direction. We arrange the high pressure piston, piston rod and crosshead to be
equal in weight to the low pressure pistons, piston rods and crossheads and we make
the high pressure connecting rod also equal to the combined weights of the low
pressure rods, and the high pressure crank pin, and crank webs respectively equal
to the combined weights of the low pressure crank pins, and crank webs.
All three pistons have the same stroke.
By thus arranging and proportioning our parts we provide in the high pressure
engine reciprocating and revolving moving masses at all times moving in opposite
directions to masses disposed at equal distances on each side of the bigh pressure
engine forming the two low pressure engines which masses are equal to each other
in weight and the sum of their weights equal those of the high pressure engine.
In this manner we perfectly balance the reciprocating and revolving parts and
also the parts which combine reciprocation and revolution and by disposing the
low pressure engines at equal distances on either side of the high pressure

page_text: engine, we prevent the production of an unbalanced couple which couple would
cause vibration.
We in like manner arrange to give the whole valve motions required by
two eccentrics disposed at equal distances on either side of the high pressure
crank centre and having the eccentric centres directly opposed to each other.
We arrange the reciprocating valve parts to be equal in weight and opposite in
movement.
By this system of arranging our engines and valve parts we are enabled to work
at very high speeds without vibration. The steam pressure on the low pressure
pistons, also being directly opposed to that in the high pressure piston causes the
strains to be taken up by the crank shaft and reduces in great measure the pressures
transmitted to the main bearings.
In applying our system of steam distribution we adopt an extension of our well
known crescent valve arrangements. Between the high pressure cylinder and one
of the low pressure cylinders we provide a valve chamber consisting of two valve
cylinders one at each end of the said chamber. Each valve cylinder carries a
piston valve, the two piston valves being in line and one of them controlling the
steam ports of the high pressure cylinder while the other controls the steam ports of
the low pressure cylinder. The two piston valves are placed in line and they are
actuated by the same eccentric and suitable connection. To enable this to be done
we carry a long passage from one end of the high pressure cylinder to a port
operated by one piston valve while the other end of the high pressure cylinder is
connected to its port by a short passage. In like manner we arrange the low
pressure cylinder with a long and short passage connecting to its steam ports
so as to enable the opposite piston valve to operate it. Between the two piston
valves thus operating together we arrange a steam chamber which chamber we
connect by a pipe or passage to a valve cylinder containing another piston valve
intended to control the steam admission and discharge from the second low pressure
cylinder.
The course and distribution of the steam is thus as follows:- -The high pressure
steam enters an annular space surrounding the high pressure piston valve at the
centre of the valve, and it is admitted and cut off alternately at each end of the
high pressure cylinder from this central space by the interual edges of the piston
valve. The said internal edges being formed by an annular recess round the piston
valve. The external edges of the pistou valve allow the exhaust steam to pass from
the high pressure cylinder at one edge through the said valve to the central steam
chamber and at the other edge directly into the central steam chamber between the
two piston valves moving together. From this central steam chamber the steam
passes by the other piston valve to one of the low pressure cylinders, and to the
separate piston valve supplying the other low pressure cylinder by way of the pipe
or passage herein before described.
The separate piston valve of the second low pressure cylinder is likewise preferably
arranged with central steam inlet and cut off edges, the external edges serving for
exhaust purposes.
We prefer piston valves in our engines but slide valves may be adopted if desired
with a similar system of steam distribution.
In applying our invention to a triple expansion engine we mount upon the middle
cylinder of the herein before described compound engine a high pressure cylinder
and prolong the valve spindle to a sufficient extent to operate another valve
preferably a piston valve of the said high pressure cylinder. The high pressure
cylinder of the compound engine thus becomes the intermediate cylinder of the
triple expansion engine and the steam is first admitted to the high pressure
cylinder from which it passes to the intermediate cylinder and thence to the two
low pressure cylinders.
In arranging a triple engine in this manner we of course alter the weight
of the intermediate piston so as to cause the high pressure and intermediate

page_text: pistons and rods to equal the united weight of the two low pressure pistons and
rods. We thus preserve our balance completely in the triple as in the compound
engine.
Dated this 4th day of October 1893.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Compound and Multiple Expansion Steam Engines.
We, GEORGE EDWARD BELLISS and ALFRED MORCOм, both of Ledsam
Street Works, in the City of Birmingham, Engineers, 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 :-
Our invention relates to compound and multiple expansion steam engines and it
is principally applicable to three crank engines of either the compound or the triple
expansion type.
Our object is to produce a compound, a triple expansion, or a multiple expansion
engine in which the high and low pressure engines or the high, intermediate, and
low pressure engines are so disposed with reference to each other as to perfectly
balance the moving parts so that each reciprocating part is perfectly balanced by
the opposite motion of another reciprocating part or parts, and each rotating or
partly rotating and partly reciprocating part is perfectly balanced by a movement
of a similar and similarly but oppositely moving part or parts.
Our object is also to minimise the pressure on the main bearings by a particular
disposition of the high and low pressure engine.
At the same time we so arrange our valve, steam ports and passages as to secure
the greatest simplicity of valve action, complete balance of valve parts and
effective steam distribution.
Our invention thus consists in a combination of engines arranged to obtain a
perfect balance and further in a novel and simple system of steam distribution
involving the use of the minimum number of valves and eccentrics.
Referring to the two accompanying sheets of drawings
Figure 1 is a longitudinal section of a three cylinder compound engine in which
our invention is carried into effect.
Figure 2 is a diagram illustrating the positions of the crank and eccentric
centres.
Figure 3 is a part section of another valve arrangement in an engine in accord
with our invention. And
Figure 4 is a part section showing a method of tripling the compound
engine shown in Figures 1, and 3.
In carrying our invention into effect as applied to a three cylinder compound
engine (Figure 1) we arrange the high pressure cylinder A between two low
pressure cylinders B and C and we connect the two low pressure pistons to
separate cranks B'C' on a crank shaft D.
The low pressure crank centres coincide with each other.
We connect the high pressure piston to a crank A directly opposed to the low
pressure cranks B² C³. The two low pressure pistons thus move to and fro
precisely together and the high pressure piston between them always moves in the
opposite direction. We arrange the high pressure piston, piston rod, and cross-
head, to be equal in weight to the low pressure pistons, piston rods and crossheads
and we make the high pressure connecting rod A' also equal to the combined
weights of the low pressure rods B'C', and the high pressure crank pin A³, and

page_text: crank webs A A' respectively equal to the combined weights of the low pressure
crank pins B2 C', and crank webs C³ C.
All three pistons have the same stroke.
By thus arranging and proportioning our parts we provide in the high pressure
engine reciprocating and revolving moving masses at all times moving in opposite
directions to masses disposed at equal distances on each side of the high pressure
engines, forming the two low pressure engines, which masses are equal to each
other in weight and the sum of their weights equal to those of the high pressure
engine. In this manner we perfectly balance the reciprocating and revolving
parts and also the parts which combine reciprocation and revolution and by
disposing the low pressure engines at equal distances on either side of the high
pressure engine, we prevent the production of an unbalanced couple which couple
would cause vibration.
We in like manner arrange to give the whole valve motions required by two
eccentrics M M' disposed at equal distances on either side of the high pressure
crank centre and having the eccentric centres together. We arrange the
reciprocating valve parts to be equal in weight and having the same movement.
We balance the moving weights of the said valve parts by the rotating balance
weights N N keyed on the crank shaft D. By this system of arranging our
engines and valve parts we are enabled to work at very high speeds without
vibration. The steam pressure on the low pressure pistons, also being directly
opposed to that in the high pressure piston causes the strains to be taken up by
the crank shaft and reduces in great measure the pressures transmitted to the
main bearings.
In applying our system of steam distribution we adopt an extension of our well
known crescent valve arrangements. Between the high pressure cylinder A and
one of the low pressure cylinders C (see Fig. 3) we provide a valve cylinder E
bored throughout, or chamber E consisting of two valve cylinders one at each
end of the said chamber. Each valve cylinder carries piston valves FF, the
two piston valves F F' being in line and one of them controlling the steam
ports of the high pressure cylinder A while the other F controls the steam ports
of the low pressure cylinder C. The two piston valves are placed in line and they
are actuated by the same eccentric as M' (Fig. 1) and suitable connections.
To enable this to be done we carry a long passage K Fig. 3 from one end of the
high pressure cylinder to a port operated by one piston valve F1 while the other
end of the high pressure cylinder A is connected to its port by a short passage I.
In like manner we arrange the low pressure cylinder C with a long and a short
passage connecting to its steam ports so as to enable the upper piston valve F to
operate it. Between the two piston valves thus operating together we arrange a
steam chamber O which chamber we may connect by a pipe or passage to a valve
cylinder E containing another piston valve G intended to control the steam
admission and discharge from the second low pressure cylinder B. This arrange-
ment is shown at Figure 3 where G is the piston valve controlling the cylinder B
and the chamber O₁ is then connected with O by a pipe not shown.
The chamber E¹ (Fig. 1) may also contain two piston valves F F acting
exactly as described in the case of the valves F F as shown at Figure 3.
In this
case the chambers O ()¹ need not be connected by a pipe or passage as the high
pressure cylinder A has then two seats of steam passages respectively KI and KI
and steam is discharged from the high pressure cylinder to both valve cylinders E
and E¹.
The course and distribution of the steam in the engine shown at Figure 1 is
thus as follows: The high pressure steam enters annular spaces H H' surrounding
the high pressure piston valves G F at the centre of the valves, and it is
admitted and cut off alternately at each end of the high pressure cylinder from
these central spaces by the internal edges of the piston valves G F¹. The said
internal edges being formed by an annular recess round each piston valve. The
external edges of the piston valves allow the exhaust steam to pass from the high

page_text: pressure cylinder A at one edge through the said valves to the central steam
chambers O O and at the other edge directly into the said central steam
chambers between the two piston valves moving together in each valve cylinder..
From these central steam chambers the steam passes by the other piston valves
respectively G and F to the low pressure cylinders B and C.
The piston valves G and F of the low pressure cylinders are preferably
arranged with external steam inlet and cut off edges, the central edges and
annular recess serving for exhaust purposes. The chambers L L¹ receive the
exhaust steam from the low pressure cylinder B and C by way of the annular recess
round each piston valve G and F and exhaust pipes conduct the exhaust steam from
these chambers to the atmosphere or the condenser as the case may be.
By the application of two sets of steam passages to the high pressure
cylinder A we avoid throttling the steam and dispense with a passage outside the
cylinder connecting the exhaust from the high pressure cylinder to the low
pressure cylinder furthest away from the side at which it is discharged; we thus
minimise cooling.
In the arrangement shown at Figure 3 the high pressure steam is supplied to the
piston valve F by way of the chamber H¹, and the exhaust from the high pressure
cylinder A passes to the chamber O¹ which is connected to the chamber O by a
pipe passing behind the engine. The low pressure cylinder Cis thus supplied with
steam direct to the valve F from the chamber O' while the valve G is supplied
from the chamber which chamber is supplied by O₁ as described. In this
arrangement there are thus three piston valves F F and G instead of four as in
the first described arrangement. Figure 2 is a diagram showing the relative
positions of the crank and eccentric centres, a is the crank centre corresponding
to the crank A and is the centre corresponding to the crank pins C B' while m
represents the centre of both eccentrics M M¹.
We prefer piston valves in our engines but slide valves may be adopted if
desired with a similar system of steam distribution.
In applying our invention to a triple expansion engine (Figure 4) we mount
upon the middle cylinder of the hereinbefore described compound engine a high
pressure cylinder P and prolong the valve spindle to a sufficient extent to operate
another valve Q preferably a piston valve of the said high pressure cylinder.
The high pressure cylinder A of the compound engine thus becomes the inter-
mediate cylinder of the triple expansion engine and the steam is first admitted to
the high pressure cylinder from which it passes to the intermediate cylinder and
thence to the two low pressure cylinders.
In arranging a triple engine in this manner we of course alter the weight of the
intermediate piston so as to cause the high pressure and intermediate pistons and
rods to equal the united weight of the two low pressure pistons and rods.
thus preserve our balance completely in the triple as in the compound engine.
We
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. A compound steam engine having three cylinders, two low pressure cylinders
and one high pressure cylinder in which the high pressure cylinder is placed
between the two low pressure cylinders and the three pistons actuate three cranks
on one crank shaft, the two outer and low pressure cranks having their centres in
line so that the two low pressure cylinders and their connections move to and
fro together, and the high pressure piston operates a crank pin placed in
opposition, at or about 180° removed from the centres of the low pressure crank
pins so that the high pressure piston and parts always move opposite in direction
to that of the low pressure piston and parts, the high pressure piston and parts
being equal in weight to the combined weight of the low pressure pistons and
parts so that a perfect balance is produced and the engine is capable of rapid
rotation as hereinbefore set forth.

page_text: 2. A compound engine as claimed in the preceding claim having equally
disposed sets of piston valves moving together and balanced by weights on the
crank shaft as herein before described and illustrated at Figures 1 and 2 of the
accompanying drawings.
3. A compound engine as claimed in the first claim in which the high pressure
cylinder has two sets of ports and a separate piston valve is applied to operate
each set of ports, each of the said two piston valves being connected to a piston
valve in line with it to control the ports of each of the low pressure cylinders,
substantially as forth.
4. A triple expansion engine with four cylinders operating as hereinbefore
described with reference to Figure 4 of the accompanying drawings.
5. A compound engine as claimed in Claim 1 having three piston valves as
herein before described with reference to Figure 3 of the accompanying
drawings.
D
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents for the Applicants