Improvements relating to Compound and Multiple Expansion Steam Engines.
Year: 1895

page_text: Date of Application, 4th Apr., 1895
Complete Specification Left, 6.h Jan.. 1896-Accepted, 8th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements relating to Compound and Multiple Expansion
Steam Engines.
We, ALFRED MORCOM and 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:-
This invention relates to improvements in compound and multiple expansion steam
engines, particularly to the type described in the Specification of Patent No. 18632
of 1893.
The object of our present invention is to effectually balance the reactions caused
by the obliquity of the connecting rods during the running of the engine.
In carrying our invention into effect as applied to a three cylinder compound
engine we preferably arrange the high pressure cylinder between the two low
pressure cylinders in the manner described in the prior Specification hereinbefore.
referred to. The outer of the low pressure piston rods are connected to separate
cranks on the crank shaft by connecting rods and crossheads in the ordinary
manner, but the cross head for the central or high pressure piston rod is arranged to
work between guides formed or attached to the bed plate on the opposite or lower
side of the crank shaft. The outer end of the high pressure piston rod is not
attached directly to its crosshead but is secured to a yoke which is connected with
the crosshead on the opposite or lower side of the crank shaft by means of a hollow
or other rods or stays, and the reciprocating movement of the position is thus
communicated to the crosshead. The connection between the lower crosshead
and its crank is then made by means of a connecting rod, working on the side
of the crank shaft opposite to the connecting rods of the outer or low pressure
cylinders.
We preferably cause the two low pressure pistons to travel precisely together, and
the high pressure piston between them to be always moving in the opposite direction.
By arranging the connecting rods on opposite sides of the crank shaft, the pressure
on the crosshead guides and the transverse stress on the crank shaft due to the
obliquity of the low pressure connecting rods, and the momentum produced by their
motion, will act in opposition to the like pressure and stress set up by the high
pressure connecting rod. The opposing forces will be thus caused to balance each
other, instead of acting together on the engine frame and on the crank shaft.
We do not limit the application of our invention to the particular form of engine
bereinbefore referred to, but adapt it to triple expansion and other engines,
making such modificatious as may be necessary to adapt it to the particular service
required.
+1 1000
MARKS & CLERK,
18 Southampton Buildings, London, W.C., and
13 Temple Street, Birmingham, Agents for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements relating to Compound and Multiple Expansion.
Steam Engines.
We, ALFRED MORCOM and G. E. BELLISS AND COMPANY LIMITED, of Ledsam
Street Werks, 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:-
This invention relates to improvements in compound and multiple expansion steam
.engines, particularly to the type described in the Specification No. 18632 of 1893,
on which Letters Patent have been granted to us.
The object of our present invention is to effectually balance the vertical
re-actions caused by the obliquity of the connecting rods during the running of the
engine.
In the accompanying sheet of explanatory drawings to be hereinafter referred
to :-
Figure 1 is a part sectional elevation representing the application of our
invention to a three cylinder compound engine such as is described in the
Specification herein before referred to.
Figure 2 is a part sectional plan showing the crank shaft and the coupling rods.
The high pressure cylinder A is arranged between the low pressure cylinders B
and B', the valves being placed on opposite sides of the high pressure cylinder as
illustrated. The outer or low pressure piston rods are connected to separate
cranks C and C₁ on the crank shaft by connecting rods and crossheads in the
ordinary manuer, but the crosshead D for the central or high pressure piston rod
is arranged to work between guides formed or attached to the bed plate on the
opposite or lower side of the crank shaft. The outer end of the high pressure
piston rod is not attached directly to its crosshead but is secured to a yoke such
as E which is connected with the crosshead D on the opposite or lower side of the
crank shaft by means of hollow or other rods or stays such as F, and the recipro-
The
cating movement of the piston is thus communicated to the crosshead.
connection between the lower crosshead and its crank is then made by means of a
return connecting rod G working on the side of the crank shaft opposite to the
connecting rods of the outer or low pressure cylinders.
We preferably cause the two low pressure pistons to travel precisely together,
and the high pressure piston between them to be always moving approximately in
the opposite direction (the weight of slide valves and parts being balanced by
moving the high pressure crank a small angle away from exact opposition) and we
arrange that the weights of the moving parts of the low pressure cylinders are
together equal to the weight of the moving parts of the high pressure cylinder.
This arrangement balances the effects due to the direct vertical action of the
momentum of the parts and also the couples produced by these vertical effects.
By arranging the connecting rods on opposite sides of the crank shaft as
illustrated, the additional vertical effects produced by the changes in momentum
due to the acceleration and retardation of. the moving parts of the low pressure
⚫ engines are exactly balanced by those of the high.
The opposing effects being thus caused to balance each other, instead of
acting together on the engine frame and on the crank shaft, vibrations due to
changes in momentum brought about by the angularity of the connecting rods, will
be prevented.
We do not limit the application of our invention to the particular form of
engine hereinbefore referred to, but adapt it to triple expansion and other
engines, making such modifications as may be necessary to adapt it to the
particular service required.

page_text: 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. The improved method of balancing the moving parts of an engine by means
of a return connecting rod substantially in conjunction with the engine having a
centre cylinder line of parts balanced in weight and in couples by two outside.
cylinders with lines of parts equal in weight to each other and of combined weight
equal to those of the middle cylinder, as set forth.
2. The improved general combination and arrangement of the moving parts.
of a compound or multiple expansion engine substantially as and for the purposes.
set forth.
Dated thin 1th 1
1000
MARKS & CLERK,
18 Southampton Buildings, London, W.C., and
13 Temple Street, Birmingham, Agents for the Applicants..