Improvements in Steam Engines.
Year: 1890

page_text: r
Date of Application (in United Kingdom), 4th Dec., 1890
Complete Specification Left, 3rd Sept., 1891-Accepted, 5th Dec., 1891
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Improvements in Steam Engines.
I, AURELIO LIBERTI of Vico Giardinetto a Toledo 57, Naples in the Kingdom
of Italy, do hereby declare the nature of this invention to be as follows:-
Necessary: Definitions... (1). In speaking hereinafter of the "mode of action" of
steam in: a cylinder it is intended to refer to the course followed by the steam from
the moment it. leaves the valve chest to enter the cylinder until it is disharged from
the cylinder of which such valve chest forms a part after the piston has completed
one forward and one backward stroke.
(2). By "back chamber" is meant that of the two compartments of the cylinder
comprised between the piston and the crown of the cylinder next to the main shaft:
and conversely the "front chamber" is that situated between the piston and the
opposite crown of the cylinder.
(3). In a steam engine operated by successive expansions in a number of separate
cylinders. (double, treble, or quadruple expansion or "compound" engines) what is
called an immission or steam inlet cylinder is that of the several cylinders which
receives steam from the condenser direct.
(4). The cylinder is said to be "in the state of reception" when its piston moves
under the pressure of the steam discharged from the immission cylinder preceding;
or in other words.the cylinder is in the "condition of a receiver" as long as lasts
the discharge into it of the steam issuing from the immission cylinder (it is clear
that with the exception of the cylinder receiving steam directly from the boiler all
the others will thus be brought consecutively into the condition of "receivers
while the steam which is delivered from the boiler after having successively
expanded escapes to the condenser).
"
(5). "Intermediate back pressure" is the back pressure exercised upon the
piston of an immission. cylinder by the steam which is being discharged from such
cylinder in order to operate the piston of the following cylinder, which latter
consequently. is in the "state of reception.".
The invention and its object. The object attained by this invention is to
counterbalance.the intermediate back pressure while the steam after having occupied
one compartment of the immission cylinder passes into the other compartment for
the purpose of operating its piston (1). It follows that the admission chamber is
not, as it.hitherto used to be, alternately connected with either of the two compart-
ments of the cylinder,.and consequently the steam is not either after the forward or
after the backward stroke of the piston, discharged into the cylinder which for the
time, being acts. as.a. receiver but oue only of the two compartments is placed in
communication with the valve chest. (If the immission cylinder is to be especially
constructed it is, sufficient to provide it with one steam port only preferably that
which corresponds.to the chamber. which is to be connected with the valve-chest if
however, an existing cylinder is to be adapted it will be sufficient to close the steam
port corresponding to the chamber so that it can under no circumstances communi-
cate with the distributing box) thus one compartment of the cylinder is alone

page_text: capable of communicating with the distributing box and only during the time that
steam is discharged from that compartment into the cylinder which happens at the
time to be the "receiving" one. The means of connection may be of any suitable
description provided it enables the exhaust steam to pass from one compartment
into the other and is fitted with a suitable distributing device such as a slide or
other valve a cock, or the like, which remains open during the escape of steam from
the then receiving cylinder but closes during the time required by the steam
expanding or otherwise to displace the piston of the said immission cylinder which
takes place either through steam pressure produced in the boiler, in the case of the
cylinder receiving steam from the boiler directly, or through the action of the
exhaust steam supplied by another immission cylinder in the instance of a cylinder
acting as a receiver.
It will be understood that as the two compartments of the immission cylinder
are connected, at the time when it discharges its steam into the next receiving
cylinder and as the steam consequently exercises the same pressure upon either side
of the piston of the immission cylinder, the intermediate back pressure is exactly
counter-balanced and the object in view fully attained, even though the piston of
the immission cylinder is not acted upon by the steam supplied by the boiler (in the
case of one of the cylinders non-connected directly with the boiler) when however
a piston is acted upon by steam (no matter whether it is the piston of the immission
cylinder communicating directly with the boiler or that of one of the other
cylinders) the object which is to reduce the back pressure or resistance opposed to
the pressure of the condenser, is also attained, as the valve (or the like) which had
opened to connect the two compartments of the immission cylinder now closes, while
on the other hand connection is made between the condenser and that compartment
of the immission cylinder which is precluded from communicating with the valve
chest.
Description of the drawing. The accompanying drawing given only by way of
example will enable the object of the invention to be readily understood although
the foregoing description is sufficient to illustrate its scope and operation. It is
assumed that the invention is applied to a vertical compound (double expansion)
engine of ordinary construction such being shown in the accompanying drawing in
vertical section on the axial line of the main shaft.
a is the front compartment of the steam inlet or immission cylinder, D the valve
chest of the same, C the connection between the two compartments of the said
cylinder, t is the valve of the same which is here shown to be a slide-valve, but
which as before stated may be of any convenient construction. A is the front
compartment of the main cylinder which in the present instance discharges the
steam after it has operated its piston, directly into the condenser.
The steam as it issues from the boiler passes through the inlet tube into the
valve-chest or distribution chamber D and hence into the front compartment a of
the immission cylinder where either with or without expansion it impinges upon the
piston of this cylinder, and causes it to complete one entire stroke, which drives
away the steam through the port H and the pipe M (which latter however may be
replaced by any suitable means of connection). The steam is thus discharged into
the valve chest D', whence through the port p it passes into the back compartment
of the lower pressure cylinder A. and after having caused the piston S of the latter
to complete one stroke it is discharged into the condenser. In order to exert an
equal pressure upon both surfaces of the immission cylinder's piston s, the steam
issues from the chamber a through the port u and passes through C and port c into,
the other compartment a' of the said cylinder as soon as the slide-valve t opens by
rising together with the valve rod T, the motion of these two parts being made
simultaneous by the lever l.
In the instance shown the so-called immission cylinder is that which communicates
with the condenser and is co-axial therewith so that the movement of both piston
rods (riz. that of the large and that of the small cylinder) being parallel, the large
cylinder receives steam from the valve-chest (in one compartment only) as soon as

page_text: it is discharged from the smaller cylinder. e indicates the means of connection
between the condenser and the back compartment of the immission cylinder and r is
the plug in the port H'.
The back pressure which resists the motion of the pistons of the immission
cylinders when such pistons are driven by steam issuing either from a boiler or from
another cylinder, made equal to the pressure existing in the condenser.
Dated this 20th day of February 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Steam Engines.
I, AURELIO LIBERTI of 57 Vico Giardinetto a Toledo Naples, in the Kingdom
of Italy, Mechanic Professor and Ship Builder, 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 :—
The principal object of this invention is to construct a compound, triple, quad-
ruple or further expansion steain engine so that the steam pressure at that side of
any of the pistons from which the steam is being exhausted may be balanced by a
corresponding steam pressure acting on the other side.
I attain this result by employing each cylinder practically as a single-acting
cylinder part of the steam introduced into one end of the cylinder for moving the
piston in one direction when exhausted from that end and when the piston is moving
in the other direction being admitted without any other steam into the other end of
the cylinder, the other part of the steam thus exhausted being used for operating
the next piston of the series either directly or after passing through an intermediate
receiver or in the case of the lowest pressure cylinder being discharged into the
atmosphere or condenser.
In the accompanying drawings are represented various forms of cylinders
constructed according to this invention.
In Figure 1 which is a central section A is the cylinder, B the piston, C the
valve casing, D the slide valve, E E' the two steam ports and F the exhaust port
all of which parts may be of ordinary construction; when my invention is applied
to an ordinary arrangement such as this 1 insert in the port E a plug E' which if
the engine is non-reversible permanently closes the passage through the port E but
which if the engine is reversible is movable and constructed like a cock plug so that
the passage through E may be opened or closed as required according to the
direction in which the engine is to work. When however constructing a new non-
reversible engine to work according to my invention then only one port cither E or E'
need be provided.
G is a second valve chest H a further slide valve and I and J J the ports
controlled by the valve H. Jare two cock plugs one fitted in each of the
ports JJ and the stems of which projecting outside the walls of the ports J J' like
that of the plug E projecting beyond the wall of port E, are suitably connected to
the reversing gear.
In the operation of the before described apparatus according to my invention
the plug E closes the port E and the steam is admitted to the valve chest C, and
by the slide valve D and port E' to the underside of the piston B in the ordinary
manner the piston being thereby raised. The slide valve H during this upstroke
of the piston makes connection between the ports and so that the steam
exhausting from the upper end of the cylinder passes to the exhaust pipe K which
with the main exhaust pipe F1 communicating with the main exhaust port F
conducts the steam into the next valve chest of the series or, in the case of the last
or lowest pressure cylinder into the atmosphere or into a condenser or other desired

page_text: apparatus. When the piston reaches its highest position the slide valve D will be
lowered and place the port E' in communication with the exhaust port F. and the
slide valve H will completely cover in the exhaust port I and uncover the ports .J.J¹
and during the whole of this stroke allow the steam to pass through J G and J¹ to
the upper end of the cylinder and operate on the upper side of the piston B so as
to balance the pressure opposed to the under side of the piston..
is
When it is desired to reverse the engine the plug E by the reversing gear
preferably turned so as to open the passage through the port E and the, plugs J'
turned so as to close the ports J J¹ the consequence of which is that the engine will
work as an ordinary double acting engine and the steam exhausted at each half or
up and down stroke will pass into the next valve chest of the series or into the
atmosphere or a condenser. The turning of E is not absolutely necessary for
reversing the engine but when turned it is found to facilitate the reversal.
Should it however be desired that my invention may apply to the working of this
engine in either direction the cock pings J may be dispensed with and as indicated
in dotted lines in Figure 1 a second plug E2 may be fitted in the port E and so
connected with the other plug E2 and reversing gear that when one is opened the
other is closed, the reversing gear at the same time also effecting the necessary
shifting of the valves D and H in relation to their eccentrics or valve gear so that
the steam may be admitted into the cylinder A at the proper part of the engine's
stroke (which in Figure 1 when so reversed would be the down stroke) and so that
during the return stroke the ports J and J¹ would be in free communication with
each other.
+ rasti it
Figs. 2 to 5 represent another arrangement of the apparatus constructed according
to my invention, Figure 2 being a vertical section and Figure 3 a back elevation of
the complete cylinder and Figures 4 and 5 are sections of a three way cock
employed in this arrangement the latter section being taken on line 5-5 of Figure 3
and the former section representing a plane at right angles to that shown in
Figure 5.
In this arrangement the cylinder A, piston B, valve chest C, slide valve D,
ports E E and F and plug E are all as before described and shown in Figure 1
but unlike the former arrangement there is no second slide valve the three way
cock L being provided instead. This cock is connected by its passage and pipe F¹
with the exhaust port F by its second passage with the pipe M which communi-
cates with the interior of the cylinder A through an opening in the cover Aor
other equivalent part and by its third passage Figures 3 and 5 with the pipe
which conducts the steam discharged from the cylinder shown in Figures 2 and 3
to the next in the series (through a receiver or not) or to the final exhaust pipe or
to a condenser. The operation of this engine according to my invention is as
follows: The plug E' is turned so as to completely close the passage through the
port E and the steam is admitted to the lower end of the cylinder A by the valve D
as in an ordinary single-acting cylinder so that the piston is thereby raised, the
upper end of the cylinder A during this upstroke being in communication with the
exhaust port F and consequently with the next cylinder of the series, if there be
one of lower pressure, through the pipe M and passages and of the three-way
cock L, the steam, previously transferred during the last down stroke of piston B
from the lower to the upper end of the cylinder A, for balancing the pressure on
the piston, being at this time discharged from the upper end through the pipe M
and passages and 12.
When it is desired to reverse the working of the last described cylinder the
plug E and the plug 3 of cock L by the reversing gear are preferably turned so as
to open the passage through the port E so as to close the passage and make
communication between 1 and 2 and place the exhaust port F directly in communi-
cation with the next lower pressure cylinder or the condenser or final exhaust pipe,
the cylinder thus acting as an ordinary double acting cylinder; the turning of E
and are not compulsory though it facilitates the reversal of the engine...
"
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"
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page_text: Should it however be desired that my invention may apply to the working of this
last described engine in either direction then another cock-plug E' is fitted in the
port El as shown in dotted lines in Figure 2 and the cock L may be provided with
a fourth passage * connected by a pipe (similar to M) with the bottom cover or
end of the cylinder or a second three-way cock may be used, all the cocks E² and L
being so arranged in connection with the reversing gear that when the ports and
passages necessary for operating the engine in one direction are opened those which
are unnecessary for such operation are closed.
The cylinder shown in section in Figure 6 represents another manner of carrying
my invention into practice. In this example the cylinder A piston B valve casing C
and ports E E and F are of usual construction but the distance between the cut-off'
edges d and the hollow of the slide valve D is much greater than the distance
between the edges e of ports E E¹ so that during nearly the whole of one of the
strokes of the piston (in the example here illustrated the down stroke) the ports E
and E communicate with each other through the hollow of valve D and moreover
the distance between the edges of of valve D as compared with the distance
between the edges el of ports E E' is greater than usual and the eccentric or gear
which operates this valve D is so arranged that only the port E will at any time
be uncovered for admitting steam from the steam chest C.
In the operation of this engine the steam from chest C passes through port. El
into the lower end of the cylinder and raises the piston B the "balancing" steam
from the upper end of the cylinder at this time passing out through port E and
under valve D into the exhaust port to be employed as before described. During
the down stroke of the piston C the steam ejected from the lower end of the
cylinder A passes through port E' and under the valve D and thence partly through
the port E into the upper end of the cylinder to balance the pressure against the
under face of the piston and partly through the exhaust F to operate the next lower
pressure cylinder or to be otherwise dealt with as before described.
This engine may be reversed by employing ordinary gear to change the position
of the valve D in relation to the eccentric or operating gear or rice versa.
In Fig. 7 I have shown in section another construction of the apparatus provided
with an additional steam port controlled by the slide valve D. In this arrangement
the cylinder A, piston B, valve chest C and ports E E' and Fare as usual
excepting that the port E¹ is provided with a branch port E3 opening through the
face on which the slide valve D works. At the junction of the port E with
port E' I provide a cock plug E' so arranged and so connected with the reversing
gear that when the engine is to work in one direction it will open communication
between the two ends of port E' and disconnect the port E³ therefrom as shown in
Figure 7 and when the engine is to work in the opposite direction the upper end of
the port E will be disconnected from, and the port E³ connected with, the lower
end of E'.
In the operation of this engine according to my invention the cock plug E
occupies the position shown in Figure 7 and the slide valve D will uncover only the
port E for the admission of steam and never the end of port E'. The steam thus
allowed to enter the upper end of the cylinder A forces down the piston B and the
previously admitted "balancing" steam admitted into the lower end of the cylinder
passes through port E' to the exhaust I to be utilized or not as before described.
During the up stroke of the piston B the slide valve D extends completely across
the ports E and the steam from the upper end of the cylinder passes through
the port E under the valve D partly to the exhaust and partly into the lower end
of the cylinder for the purpose before explained.
When it is desired to work this engine in the reverse direction the reversing gear
is operated and besides effecting the usual adjustment in the valve gear also turns
the plug E so as to close the passage from end to end of the port E and connect
the port E with it as will be well understood. The engine when worked with
this adjustment will operate as an ordinary double acting engine.

page_text: In carrying out my invention so that it may apply to the working in either
direction of this engine may provide a duplicate port E3 and cock plug E' to
operate in conjunction with the port. I like the port E³ and cock plug E shown
does in conjunction with the port E' as will be well understood.
Figure 8 is a section of a horizontal cylinder fitted with Sultzer's gear and having
my improvements applied thereto.
In this example the steam first enters the chamber N through the cock O and
from this chamber its admission to the cylinder A is controlled by the valve P.
As soon as this valve P is opened, the steam enters the cylinder and moves the
piston B from left to right as in Figure 8 the "balancing" steam previously
admitted to the other side of the piston meanwhile escaping through the valve Pi
into the chamber N' whence it is conducted through cock O' to the next lower-
pressure cylinder or condenser or to be otherwise disposed of as required. During
the right to left stroke of the piston B no fresh steam is admitted to the cylinder
the cock O2 being for this purpose closed but some of the steam exhausting from the
left hand side of the piston through the valve P2 passes from the chamber N2 through
a passage represented in dotted lines in Figure 8 to the chamber N³ and enters
the right-hand end of the cylinder to "balance" the pressure on the piston as
before described through the valve P³ the remaining portion of the steam passes
from chamber N2 through cock 03 and is conducted to the next lower-pressure
cylinder or to be otherwise dealt with.
The passage is provided with a cock Q' which like the other cocks O O¹ O² ()³
is connected with the reversing gear which when operated causes the engine to be
operated as ordinarily. If however it be desired to apply my invention to the
working of the engine in either direction I may provide another passage and
cock QQ in conjunction with the chambers N N' and arrange the reversing gear
so that when the cocks necessary for working the engine in one direction are turned
on, the other then unnecessary cocks are turned off.
The before described arrangement shown in Figure 8 may be used in connection
with Corliss gear.
The apparatus before described may be modified without departing from the
spirit of the invention.
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 :-
1. In a compound triple or further expansion steam engine the method of
balancing the pressure opposed to a piston by the steam being ejected from one end
of a cylinder by admitting some of the steam thus discharged into the other end
of the cylinder substantially as described.
2. In a compound triple or further expansion steam engine the employment of
steam previously utilized for balancing the pressure opposed to a piston in one
cylinder as set forth in the preceding claim by delivering same to a lower-pressure
cylinder substantially as and for the purpose described.
3. The combination and arrangement of parts constituting the apparatus operating
substantially as and for the purpose described and illustrated in Figure 1 of the
accompanying drawings.
4. The combination and arrangement of parts constituting the apparatus operating
substantially as and for the purpose described and illustrated in Figures 2 to 5 of
the accompanying drawings.
5. The combination and arrangement of parts constituting the apparatus operating
substantially as and for the purpose described and illustrated in Figure 6 of the
accompanying drawings.
6. The combination and arrangement of parts constituting the apparatus operating
substantially as and for the purpose described and illustrated in Figure 7 of the
accompanying drawings.

page_text: 7. The combination and arrangement of parts constituting the apparatus operating
substantially as and for the purpose described and illustrated in Figure 8 of the
accompanying drawings.
Dated this 1nt Inc.
Aument 1001
AURELIO LIBERTI.
W. P. Thompson & Boult,
Agents for the Applicant.