Improvements in Compound and other Multiple-expansion Engines.
Year: 1899

page_text: Date of Application, 9th Jan., 1899 - Accepted, 11th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in Compound and other Multiple-expansion Engines.
I, ALFRED HENRY CROCKFORD, of 76, Lowfield Street, Dartford, in the County
of Kent, 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 invention relates to compound and other multiple-expansion engines, and has
for its main object to provide an improved engine of this kind which shall be
approximately balanced, that is to say, in which forces of approximately equal
magnitude shall act in inverse directions upon cranks set at an angle of one-
hundred-and-eighty degrees, and in which, consequently, the vibration will be
reduced to a minimum.
In the Specification of former Letters Patent granted to me and dated 29th
August 1896, No. 19,120, I have described various forms of a double-acting
balanced fluid-pressure engine in which the cylinders are arranged radially to a
rotary crank shaft and are joined end to end about the said shaft, the cranks, to
which the pistons of the said cylinders are coupled, being set at an angle of one-
hundred-and-eighty degrees, and the cylinders and the distributing-valve or valves
are supported by and capable of being rocked about the said crank-shaft.
A compound engine is described in the said former specification which has two
high-pressure cylinders arranged opposite each other, and two low-pressure
cylinders also arranged opposite each other at an angle of ninety degrees to the
said high-pressure cylinders, the pistons of one high-pressure and one low-pressure
cylinder being coupled to each crank.
By my present improvements I provide a double-acting approximately balanced
compound or multiple-expansion engine in which two cylinders (for example, a
high-pressure and a low-pressure cylinder, or two high-pressure or two low-pressure
cylinders) are joined end to end with a rotary crank-shaft extending transversely
between them, and in which a high-pressure cylinder and a low-pressure cylinder
are situated on opposite sides of the rotary crank-shaft and have their pistons
coupled respectively to cranks thereon set at an angle of one-hundred-and-eighty
degrees. And I make the said cylinders of such relative proportions that forces
the said cranks in
of equal magnitude will be applied through their pistons to
inverse directions.
In my improved compound engine, the high-pressure cylinder and the low-
pressure cylinder, which are situated on opposite sides of the crank-shaft, are
joined end to end with the said crank-shaft extending transversely between them.
In one form of triple-expansion engine constructed according to my said inven-
tion, two low-pressure cylinders are joined end to end with the crank-shaft extending
transversely between them, and a high-pressure cylinder is arranged at a suitable
distance from one end, and an intermediate cylinder at a suitable distance
from the other end of the said low-pressure cylinders. The piston-rods
of the said low-pressure cylinders are connected in any suitable manner

page_text: with the piston-rods of the said high-pressure and intermediate cylinders
respectively, the pistons on one side of the shaft being all coupled to
one crank or sets of cranks and those on the other side thereof to the
other crank or set of cranks. I can, however, arrange the cylinders, when more
than two are employed, in any other suitable order; for instance, in another form
of my triple-expansion engine two high-pressure cylinders are joined end to end
with the crank-shaft extending transversely between them, and an intermediate
cylinder and a low-pressure cylinder are arranged at a suitable distance from the
respective ends of the said high-pressure cylinders, the pistons being intercon-
nected and coupled to the cranks respectively as above mentioned.
In all cases, I make the cross-sectional areas of the several cylinders of such
relative proportion as to ensure an approximately balanced action upon the crank-
shaft, having regard to the degree of initial pressure to be used in the high-pressure
cylinder or cylinders.
I mount the crank-shaft.in suitable journal-bearings situated one at either side
of the cylinders. In some cases; instead of securing the cylinders to a bed-plate,
entablature or the like; I so arrange the same that they are supported solely by the
crank-shaft and can be turned or rocked about the same through a suitable angle to
shift the engine from its dead centres and thus facilitate the starting thereof."
Another object of my said invention is to provide for enabling the engine to be
used alternatively as a compound or multiple-expansion engine or as a high-
pressure engine or one with fewer stages of expansion, without any alteration in
its construction, the change from one mode of working to the other being brought
about simply by the adjustment of certain valves or cocks.
A further object of my said invention is to provide for very readily adapting the
engine for use with one or more of the cylinders inoperative, so that, should one
cylinder break down, the other cylinder or cylinders can still be used.
In the accompanying drawings I have shown how my said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a plan, and
Figure 2 a vertical longitudinal central section of a compound engine constructed
in accordance with my said invention.
Figure 3 is a transverse section on the line AB, Figure 1, and
Figure 4 is a transverse section on the line C-D, Figure 1,
Figure 5 is a diagram, illustrating the means employed for simultaneously
operating the distributing-valves.
Figure 6 is a plan, and
Figure 7 a vertical longitudinal central section of a triple-expansion engine
constructed according to my said invention.
Figures 8 and 9 are vertical longitudinal central sections showing other modifi-
cations of my invention.
a is the high-pressure cylinder and the low-pressure cylinder, which, in the
arrangement shown in Figures 1 to 4, are joined end to end in any convenient
manner; and are each closed at both ends; c is the rotary crank-shaft, which extends
transversely between the joined ends of these cylinders, through a bearing & formed
in the same.
C
Cross-heads e fixed upon the piston-rods f are coupled respectively, by connect-
ing rods g. to cranks h, j, set at an angle of one-hundred-and-eighty degrees, sub-
stantially as described in my said former specification.
Each of the cylinders a, b, Figures 1 to 4, is provided with an oscillating dis-
tributing-valve k arranged in a casing on the outside of the corresponding cylinder;
these valves are operated simultaneously in inverse directions by a single eccentric 1,
Figure 5, mounted upon the crank-shaft c, the red of the said eccentric being
coupled to an arm m on one valve-spindle, on which is also fixed another arm n
coupled by a link o to a similar arm n on the other valve-spindle.
The steam supply-nine p is connected with the valve-casing of the high-pressure
cylinder a through a suitable controlling cock q, which is also connected by a piper

page_text: with the valve-casing of the low-pressure cylinder b, the said cock being so con-
structed that communication can be thereby established between the said pipe p
and either the high-pressure valve-casing only, or both the high and low-pressure
valve-casings.
The exhaust-chamber of the high-pressure cylinder a is connected with the valve-
casing of the low-pressure cylinder 6 by a pipe s provided with a suitable controll-
ing cock t, which is also connected with an exhaust-pipe u. The plugs of these
two cocks and t are preferably adapted to be turned simultaneously in opposite
directions by means of a hand-lever suitably connected with the said plugs, as
shown, for example, in Figure 2.
By turning the plugs of these cocks 9 and t into one or other of two positions,
steam direct from the boiler can be admitted to the high-pressure valve-casing
only, or to both valve-casings, and consequently the engine can be used alter-
natively either as a compound engine or as a two-cylinder high-pressure engine.
When the engine is to be worked as a compound engine, the cock 7 is adjusted
to the position shown in Figure 2, the cock t being simultaneously adjusted so
as to permit the flow of exhaust-steam from the high-pressure cylinder a through
the pipe s into the valve-casing of the low-pressure cylinder b. When the engine
is to be worked as a high-pressure engine, the cock is adjusted so as to admit
steam from the pipe p to both valve-casings, and the cock is simultaneously
adjusted so as to close the communication between the high-pressure exhaust-
chamber and the valve-casing of the low-pressure cylinder, and put the said
exhaust-chamber in communication with the exhaust-pipe u. The said exhaust
pipe u may, if desired, be connected with the pipe which connects the exhaust-
chamber of the low-pressure cylinder with the condenser, which latter is not shown
in the drawings. A back-pressure valve should be provided on the condenser to
permit the escape of the surplus steam when both cylinders are worked under
high-pressure.
Should the high-pressure cylinder at any time break down, the engine can be
very readily adapted for use with that cylinder inoperative, by simply discon-
necting the plugs of the cocks q and t and so adjusting these cocks that the low-
pressure cylinder can be worked alone with high-pressure steam, the piston of the
cylinder a being either disconnected or allowed to run idly, as may be desired.
The cylinders a and b are made of such relative proportions, having regard to the
initial pressure to be used in the high-pressure cylinder, that forces of approxi-
mately equal magnitude will be applied in opposite directions, as a couple," to
the cranks h and j.
66
I thus provide an approximately balanced compound engine which will occupy
but little space in proportion to its power.
I sometimes provide a sheet-métal casing fitted around the cylinders as shown
in Figures 1 to 4.
In the arrangement shown in these figures, the cylinders are supported solely
ly the crank-shaft, and they may be provided with suitable means for rocking
them about the said shaft through a suitable angle to shift the engine from its
dead centres and thus facilitate its starting. If desired, however, the said cylinders
may be rigidly secured to a bed-plate, entablature or the like.
In the triple-expansion engine shown in Figures 6 and 7, there are two low-
pressure cylinders & joined end to end about the rotary crank-shaft c. and opening
into each other so as to virtually form a single cylinder with two pistons which
move in inverse directions. These cylinders are provided with a common distribut-
ing-valve r, such, for example, as is described in my said former specification.
The piston-rods f are coupled respectively to the cranks through cross-heads e and
connecting rods g, as above described. A high-pressure cylinder a is arranged at
a suitable distance from one end of the said low-pressure cylinders, and an inter-
mediate cylinder y at a suitable distance from the opposite end of the said low-
pressure cylinders; and the pistons of the said cylinders a, y are connected respec-
tively with those of the low-pressure cylinders through the cross-heads c, which,

page_text: in this case, are situated between the said cylinders a, y and the low-pressure
cylinders respectively.
The exhaust-chamber of the high-pressure cylinder a is connected by a pipe s
with the valve-casing of the intermediate cylinder y, and the exhaust-chamber of
the latter by a pipe 2 with the valve-casing of the low-pressure cylinders b.
:
To enable the engine to be readily adapted for use with one or two of the cylinders
inoperative, I provide it with the following arrangement of pipes and valves or
cocks, viz. The steam supply-pipe is connected with the valve-casing of the
high-pressure cylinder by a pipe 1 provided with a controlling valve or cock 2:
with the valve-casing of the intermediate cylinder y by a pipe 3 provided with a
controlling valve or cock 4; and with the valve-casing of the low-pressure
cylinders by a pipe 5 provided with a controlling valve or cock 6. The cocks
shown at 4 and 6 are made with open-bottom plugs and are adapted to put the
corresponding valve-casings in communication either with the steam supply-pipe p
or with the exhaust-pipe s or z, as the case may be, of the preceding cylinder. By
closing the cock 2 and adjusting the cock 4 so as to put the valve-casing of the
intermediate cylinder y in communication with the pipe p, this cylinder can be
used as a high-pressure cylinder together with the low-pressure cylinders b, the
cylinder a being inoperative. By closing both of the cocks 2 and 4, and adjust-
ing the cock 6 so as to put the valve-casing of the low-pressure cylinders in com-
munication with the pipe p, these cylinders can be used as high-pressure cylinders,
the other two being left inoperative and their pistons either disconnected or
allowed to run idly, as desired.
To provide for enabling the cylinders a and y to be used with the low-pressure
cylinders inoperative, or the cylinders a and b to be used with the intermediate
cylinder y inoperative, I sometimes connect the pipe z with the low-pressure
exhaust-pipe 7 by a pipe 8 provided with a controlling valve or cock 9, and the
pipes with the pipe by means of a pipe 10 provided with a controlling valve or
cock 11. By closing the cock 6 and opening the cocks 2 and 9, the cock 4 being
so adjusted as to put the corresponding valve-casing in communication with the
pipes, the cylinder y can be used as a low-pressure cylinder together with the
high-pressure cylinder a. Or by closing the cocks 4 and 9 and opening the cocks 2
and 11, the cock 6 being so adjusted as to put the corresponding valve-casing in
communication with the pipe z, the high-pressure cylinder a can be used with the
low-pressure cylinders b, the cylinder y being left inoperative.
The cylinders, b and y are preferably arranged as shown so that their axes
are in the same straight line, and are made of such relative proportions in cross-
sectional area that the pistons on either side of the crank-shaft will exert forces
of approximately equal magnitude in inverse directions, and thus ensure an
approximately balanced action. The said cylinders are shown secured to a bed-
plate 12; they may, however, be rigidly connected by means of rods or bolts or
in any other convenient manner, and be supported solely by the crank-shaft and
provided with means for rocking them about the same through a suitable angle
to shift the engine from its dead centres and thus facilitate its starting. The
distributing-valves may be operated substantially as above described with reference
to Figure 5.
In the triple-expansion engine shown in Figure 8, the pistons of the low-pres-
sure cylinders 6 are coupled directly, by connecting-rods g, to cranks h, j within
the said cylinders, and are connected by the piston-rods f with the pistons of the
high-pressure and intermediate cylinders a and y respectively. The engine is,
with these exceptions, constructed substantially as described with reference to
Figures 6 and 7.
In Figure 9, I have shown another modification of my improved engine, in which
two high-pressure cylinders a are joined end to end and open into each other so
as to form virtually a single cylinder with two pistons moving in inverse directions,
the crank-shaft e extending transversely through a bearing a between them, and an
intermediate cylinder y and a low-pressure cylinder bare arranged at suitable

page_text: distances respectively from the outer ends of the said high-pressure cylinders, the
pistons of the said intermediate and low-pressure cylinders being connected with
those of the high-pressure cylinders. The piston-rods f, in the arrangement shown,
are each made in one piece and the cross-heads e are fixed on the outer ends of the
said rods. It is obvious that this arrangement of the cross-heads can, if desired,
be applied to the engine shown in Figures 6 and 7, or the arrangement of the cross-
heads shown in Figures 6 and 7 can be applied to the engine shown in Figure 9.
Or the piston-rods shown in Figure S or Figure 9, instead of being made in a
single piece, can be made in two lengths connected by means of a suitable coupling
situated between the respective cylinders.
It is evident, moreover, that the construction of my improved engine can be
somewhat further modified without departing from the nature of my said invention.
For instance by adding two more cylinders to the arrangement shown in Figures 1
to 4 and suitably proportioning the several cylinders, I can make an approximately
balanced quadruple-expansion engine according to my said invention.
In cases where the crank-shaft is built up or is made in two parts, the central
cylinders can, if desired, be formed in one casting.
The axes of the cylinders on one side of the crank-shaft may, if desired, be
slightly inclined to the axes of the cylinders on the other side thereof.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. A double-acting compound or other multiple-expansion engine in which two
cylinders are joined end to end with a rotary crank-shaft extending transversely
between them, and in which a high-pressure cylinder and a low-pressure cylinder
are situated on opposite sides of the said shaft and have their pistons coupled
respectively to cranks thereon set at an angle of one-hundred-and-eighty degrees.
2. A double-acting compound or other multiple-expansion engine comprising
a high-pressure cylinder and a low-pressure cylinder situated on opposite sides of
a rotary crank-shaft and having their pistons coupled respectively to cranks thereon
set at an angle of one-hundred-and-eighty degrees, and wherein all the cylinders
are supported by and movable about the said crank-shaft.
3. A compound or other multiple-expansion engine wherein the axes of all the
cylinders are in the same straight line and the crank-shaft extends transversely
between the joined ends of two of the said cylinders, the piston or pistons on either
side of the said shaft being coupled respectively to cranks thereon set at an angle
of one-hundred-and-eighty degrees, and which is so constructed that approximately
equal forces will be exerted in inverse directions upon the said cranks, substantially
as hereinbefore described.
4. A compound or other multiple-expansion engine wherein the axes of all the
cylinders are in the same straight line and the said cylinders and their distributing-
valves are supported by and movable about a rotary crank-shaft extending between
the joined ends of two of the said cylinders, the piston or pistons on either side of
the said shaft being coupled respectively to cranks thereon set at an angle of one-
hundred-and-eighty degrees.
5. A double-acting compound engine comprising a high-pressure cylinder and
a low-pressure cylinder situated on opposite sides of a rotary crank-shaft and joined
end to end with the crank-shaft extending transversely between them and having
their pistons coupled respectively to cranks on the said shaft set at an angle of one-
hundred-and-eighty degrees.
6. A multiple-expansion engine comprising two low-pressure cylinders joined
end to end with the crank-shaft extending transversely between them, a high-
pressure cylinder and an intermediate cylinder arranged at suitable distances from
either end of the said low-pressure cylinders and having their pistons connected
respectively with those of the said low-pressure cylinders and coupled respectively
to cranks on the said shaft set at an angle of one-hundred-and-eighty degrees.

page_text: 7. A multiple-expansion engine comprising two high-pressure cylinders joined
end to end with the crank-shaft extending transversely between them, and an
intermediate cylinder and a low-pressure cylinder arranged at suitable distances
from either end of the said high-pressure cylinders and having their pistons con-
nected respectively to those of the said high-pressure cylinders and coupled respec-
tively to cranks on the said shaft set at an angle of one-hundred-and-eighty degrees.
8. A double-acting engine constructed substantially as hereinbefore described
so that it can be used alternatively as a compound or multiple-expansion engine or
as a high-pressure engine or one with fewer stages of expansion, the change from
one mode of working to the other being effected simply by the adjustment of con-
trolling cocks or valves, as above specified.
9. A compound or multiple-expansion engine constructed substantially as herein-
before described so that, in case of emergency, it can, by the simple adjustment of
controlling cocks or valves, be adapted for use with one or more of the cylinders
inoperative, as above specified.
10. The improved compound or multiple-expansion engine constructed. substan-
tially as described with reference to either of the forms or modifications illustrated
in the accompanying drawings.
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2000
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.