Improvements in Double or Multiple Cylinder Engines.
Year: 1892

page_text: .
COMPLETE SPECIFICATION;
Improvements in Double or Multiple Cylinder Engines.
1, ALFRED COLLMANN of III Beatrixgasse No. 18 Vienna, Mechanical
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 :-
This invention relates to steam engines having two or more cylinders and its
object is to provide for balancing the reciprocating parts so that a quiet motion of
the engine is obtained even with high running speeds.
In the accompanying drawings:
Fig. 1 is a longitudinal section partly in elevation and Fig. 2 is a sectional plan
of a single horizontal compound engine.
Fig. 3 is a vertical section partly in elevation of a single vertical compound'
engine.
Fig. 4 is a vertical section partly in elevation of a double vertical compound
engine according to my invention.
In the engine shewn in Figs. 1 and 2 I place the cylinder N behind H and to one
side so that the piston rod of N passes the side of H. The piston rods of both
cylinders are connected to opposite cranks K' K".
Thus when the pistons, piston rods, cross heads and connecting rods of both
cylinders H and N are made equal in weight, the equal masses reciprocating in
opposite directions balance each other completely in the direction of the axes of
the cylinders, and very nearly in the transverse direction, the distance of the axes
of the two cylinders being as small as possible.
Therefore, firstly the strains resulting from inertia and momentum of the two
pistons and their connected moving parts are not transmitted to the foundation but
are taken up directly by and balance each other in the straight middle arm m m of
the double crank; secondly, the bed plate of the engine has not to transmit much
more than the difference of the work of the two cylinders; and thirdly, the crank
shaft bearings are charged with only this difference as alternating strains.
smaller foundations and weaker bed plates may be employed and quict motion with
high speed are secured.
Hence
The two cylinders arranged the one behind the other as shewn in Figs. 1 and 2
or the one above the other as in Fig. 3 may have equal diameters constituting a
twin engine, or as shewn in the figures, they may be of different diameters
constituting a compound engine.
As shewn in Fig. 4 a double compound engine may be constructed according to
my invention by causing the steam from the high pressure cylinder I to pass to the
medium pressure cylinder 11 and employing instead of a single third expansion
cylinder, two low pressure cylinders III III" each having half the area which a
single low pressure cylinder otherwise would have.
As shewn in Fig. 4 the piston of the high pressure cylinder I and of one of the
low pressure cylinders 111 are of equal weight connected to opposite cranks KK.
The medium pressure cylinder 11 and the other low pressure cylinder III" have
their pistons similarly connected to another pair of opposite cranks. The one pair
of these two double cranks is set at an angle of 90° to 110° to the other pair
according to the intended rate of total expansion in order to obtain as great as
possible uniformity of tangential forces.
By this arrangement I can as shewn in Fig. 4 employ fly discs S S S S on the
cranks and so avoid the use of a separate fly wheel, which, particularly in dynamc-
driving plants perinits of a much more compact arrangement.
For very high steam pressures, I can convert the double compound engine shewn

page_text: in Fig. 4 into a triple compound engine by using the cylinder III' to act alone as
the third expansion cylinder and enlarging the cylinder III" for acting as fourth
and last expansion cylinder.
The engine may be made in two halves separated along the line X X¹ Fig. 4,
each half having a separate frame V between which the fly wheel and also the
governor may be arranged.
In this novel arrangement of the cylinders the rear end or head of the high
pressure cylinder forms usually the front end or bottom of the low pressure
cylinder, and the piston rod of the latter works in a tube C C cast on to the high
pressure cylinder having its stuffing box s at the front end of this tube.
In large engines the low pressure cylinder may, as shewn in Fig. 3 have a
separate lower head, the tube CC being cast on this head.and extending downwards
along the high pressure cylinder.
In very large engines it may be practicable to dispense with the tube C C and to
arrange the stuffing box s on the lower cover of the low pressure cylinder, in
which case the low pressure piston rod would pass clear along the high pressure
cylinder.
In order, particularly in smaller engines, to facilitate removal of the high pressure
piston H, the cylinder cover is made in two pieces as shewn in the drawings, so
that the inner part D can be first removed, and then the ring portion D' which is
made in one piece with the stuffing box s can be drawn away sliding along the low'
pressure piston rod and along the cross head guides.
Although in larger steain engines thus arranged valve gear of various kinds may
be employed, it is advisable for the sake of compactness to arrange the valve gear
as shewn with piston valves P and Q in such a manner that the high pressure valve
is placed at the low pressure side and the low pressure valve at the high pressure
side of the crank. By this reversed arrangement the engine is made as compact as
possible and direct eccentric motions E E and F F" are obtained.
The governing expansion gear acts as shewn in Figs. 1 and 2 directly upon the
main valve P, or as in Figs. 3 and 4 on a separate expansion valve in the main
valve and operated by a fly wheel governor; or a vertical governor actuated by
gear wheels may work the expansion gear in the usual way..
The valve gear is preferably arranged as shewn inside the crank shaft bearings,
particularly when the engines have to be directly coupled with dynamo-electric
machines at B B.
Having now particularly described and ascertained the nature of my said
invention and in what manner the saine is to be performed, I declare that what I
claim is :
1. A steam engine having two or more cylinders arranged in couples, the one of
each couple behind the other and so far to one side that the piston rod of the'
rear cylinder passes as closely as possible along the front cylinder having also
reciprocating parts of the cylinders equal in weight and connected to opposite
cranks substantially as and for the purpose set forth..
2. The double compound engine without flywheel substantially as described with'
reference to Fig. 4.
3. The arrangement of the piston valve gear PQ, substantially as described.
Dated this 31st dow of durust 1805
ABEL & IMRAY,
Agents for the Applicant.