IMPROVEMENTS IN STEAM AND OTHER ENGINES
Year: 1885

page_text: I SEBASTIAN ZIANI DE FERRANTI of 5 Stanwick Road West Kensington in
the County of Middlesex Electrician do hereby declare the nature of my invention
for "IMPROVEMENTS IN STEAM AND OTHER ENGINES' to be as follows:-
"
In steam and other engines constructed according to this invention two
connecting rods passing from two pistons are arranged to work upon a single
crank pin of a crank shaft, each piston is arranged to act in one direction only,
and one connecting rod is always maintained in compression whilst the other rod
is maintained in tension. Preferably the two pistons are arranged concentrically
one within the other, the outer one being made to work in a fixed cylinder and the
inner one being made to work in a cylinder formed by the hollow interior of the
outer piston. Steam may be admitted to the outer fixed cylinder by ordinary
valves but preferably I arrange for it to be admitted through ports in the pistons
which ports are opened and closed partly by the to and fro traverse of the pistons
and partly by the pistons being caused to move relatively the one to the other at
each end of the stroke.
To effect this I connect the one piston by a rod jointed to it, on one side of the
centre of its end, to the crank pin and the other piston by a rod jointed to it on
the opposite side of the centre of its end so that as the crank pin passes over the
dead centre one piston will be moved somewhat towards the crank shaft and the
other way from it. In this case to admit steam to the cylinders I form the outer
fixed cylinder with a central tubular passage extending inwards into it from its rear
end such steam passage opening into a steam chamber at the rear end of the cylinder
and having a series of ports or openings formed through its sides near its inner
end-the inner piston I form with a central cylindrical rod which embraces this
tubular steam inlet and extends beyond it. The end of this rod is closed and the
pressure of steam acting against the closed end maintains a constant thrust upon
the connecting rod which is jointed to it. Through this cylindrical rod I form
ports which towards the outer end of the stroke of the pistons come opposite to
the ports or openings in the steam admission passage.
The outer piston I also form with a cylindrical rod which embraces the rod of
the inner piston and which also fits within the interior of a tubular neck which
'

page_text: extends from the inner end of the cylinder and which serves as a guide. Through
the cylindrical rod of the outer piston I form ports which by the relative movement
of the two pistons at the end of the instroke are caused to come opposite to the
ports in the rod of the inner piston, so that at the commencement of the outer
stroke of the pistons steam is admitted to the inner end of the fixed outer cylinder
and acts upon the inner end of the outer piston and forces the piston upwards
whilst the inner piston is carried along with it by the thrust of its connecting rod
-steam is so admitted until the ports of the inner piston have by its movement
been carried past the steam admission ports in the fixed central steam admission
passage.
At the completion of the outward stroke ports formed through the outer piston
are by the movement which the pistons then make relatively the one to the other
brought opposite to ports formed through the inner piston, and steam is thereby
allowed to pass from the inner end of the cylinder to its outer end. The steam
then acts against the inner piston which is of larger area than the annular surface
forming the acting surface of the outer piston so that the pistons are caused to
travel in the opposite direction and to make the instroke. At the completion of
the in-stroke the outer piston passes beyond ports in the sides of the fixed outer
cylinder through which steam is allowed to escape from the outer end of the fixed
cylinder and the greater part of the steam in this end of the cylinder is so
exhausted. After a short portion of the out-stroke has been completed this direct
opening to the exhaust is closed by the piston travelling beyond the exhaust port
but the relative movement which the two pistons then receive one within the other
brings a port which is formed through the inner piston opposite to a port in the
outer piston which now also comes opposite to the exhaust port in the side of the
fixed outer cylinder, and in this way a further exhaust is given from the outer
end of the cylinder during the greater part of the return stroke.
The quantity of steam allowed to pass to the cylinder at each stroke I regulate
by a tubular slide which can be moved endwise to and fro within the central steam
admission tube so as to cover over a greater or lesser number of the steam ports
or passages formed through its sides. This tubular slide or cut off valve can be
moved to and fro by the action of the governor, and as the tube forms a perfectly
balanced valve-very little power will have to be exerted by the governor to move
it to and fro.
This way of controlling the admission of steam to the cylinder of a steam
engine by a sliding balanced valve worked to and fro by the governor is applicable
to other forms of steam engines.
The connecting rod which passes from the inner piston to the crank pin is as
before stated maintained in compression by the pressure of steam acting on the
closed end of its rod, whilst the outer piston is always pressed in the opposite
direction so as to keep its connecting rod in tension by reason of their being
always some steam present in the inner end of the outer fixed cylinder. In order
also that the two connecting rods may respectively be maintained constantly in
tension and in compression, I apply springs to the inner ends of the two pistons
which tend always to press the one piston outwards and the other inwards.
By constructing the engine in this way I obtain a double acting engine without_
reversal of strains on the connecting rods and the joints which connect them to
the pistons and crank pin respectively, also by duplicating the arrangement a
quadruple action engine might similarly be obtained.
In this case the two fixed cylinders might either be side by side or opposite one
another.
When it is desired to make the engine capable of being reversed I provide
means of giving a half turn to the two pistons so as to reverse their relative
positions by which means the relative movements which are given to the two
pistons at the ends of the strokes will also be reversed and the engine will thereby
be caused to run in the opposite direction..

page_text: The valve arrangements above described may be used for controlling the admission
of steam to and its escape from the cylinder or pair of cylinders of an ordinary
steam engine.
In this case the two parts forming the valve would be carried to and fro with
the piston of the cylinder and would in addition be moved relatively the one to
the other at each end of the stroke. To effect this the two parts might be coupled
by links to arms projecting from opposite sides of the pin used to connect the
piston rod to the connecting rod and this pin be fixed in the connecting rod-The
cut off valve herein before described which is under the control of the governor
can also be used with this valve mechanism.

page_text: Improvements in Steam and other Engines.
I SEBASTIAN ZIANI DE FERRANTI of 5 Stanwick Road West Kensington in the
County of Middlesex Electrician 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:-
In steam and other engines constructed according to this invention two con-
necting rods passing from two pistons are arranged to work upon a single crank
pin of a crank shaft, cach piston is arranged to act in one direction only, and one
connecting rod is always maintained in compression whilst the other rod is main-
tained in tension.
The two pistons are arranged concentrically one within the other, the outer one
being made to work in a fixed cylinder and the inner one being made to work in
a cylinder formed by the hollow interior of the outer piston. Steam may be
admitted to the outer fixed cylinder by ordinary valves but preferably I arrange
for it to be admitted through ports in the pistons which ports are opened and closed
partly by the to and fro traverse of the pistons and partly by the pistons being
caused to move relatively the one to the other at each end of the stroke.
To effect this I connect the one piston to the crank pin by a rod jointed to that
piston, on one side of the centre of its end, and the other piston I connect to the
crank pin by a rod jointed to it on the opposite side of the centre of its end so that
as the crank pin passes over the dead centre one piston will be moved somewhat
towards the crank shaft and the other away from it. In this case to admit steam
to the cylinders I form the outer fixed cylinder with a central tubular
ar passage
extending inwards into it from its rear end such steam passage opening into a steam
chamber at the rear end of the cylinder and having a series of ports or openings
formed through its sides near its inner end-the inner piston I form with a central
cylindrical rod which embraces this tubular steam inlet and extends beyond it.
Through this cylindrical rod I form ports which towards the outer end of the
stroke of the pistons come opposite to the ports or openings in the steam admission
passage and admit steam to the inner end of the cylinder to effect the out stroke.
The instroke is subsequently effected by the admission of the steam from this end
of the cylinder into the outer end where it acts upon the inner piston the area of
which is greater than the effective area of the outer piston upon which the steam
is then pressing to force it in the opposite direction. The passage of steam to
either end of the cylinder and its exhaust from the outer end are controlled by the
movement of the two pistons as herein after more fully explained.
The quantity of steam allowed to pass to the cylinder at each stroke I regulate
by a tubular slide which can be moved endwise to and fro within the central steam
admission tube so as to cover over a greater or lesser number of the steam ports or
passages formed through its sides. This tubular slide or cut off valve can be moved
to and fro by the action of the governor and as the tube forms a perfectly balanced
valve very little power will have to be exerted by the governor to move it to
and fro.

page_text: A non reciprocating cut off valve seat and sliding balanced valve worked to and
fro by the governor as above described is applicable for controlling the admission
of steam to the cylinders of other forms of steam engines so as to vary the expansion
of steam therein.
The connecting rod which passes from the inner piston to the crank pin is main-
tained in compression by the pressure of steam acting on the closed end of its rod,
whilst the outer piston is always pressed in the opposite direction so as to keep its
connecting rod in tension by reason of there being always some steam present in
the inner end of the outer fixed cylinder. For pressing the two pistons at all
times in two opposite directions to further effect this object I also use springs or
steam acting as a spring as herein after more fully described.
By constructing the engine in this way I obtain a double acting engine without
reversal of strains on the connecting rods and the joints which connect them to the
pistons and crank pin respectively, also by duplicating the arrangement a quad-
ruple expansion engine with two cylinders each having internal valve gear might
be obtained. In this case the two fixed cylinders might either be side by side or
opposite one another.
When it is desired to make the engine capable of being reversed I provide means
of giving a half turn to the two pistons so as to reverse their relative positions by
which means the relative movements which are given to the two pistons at the
ends of the strokes will also be reversed and the engine will thereby be caused to
run in the opposite direction.
Figures 1 and 2 of the drawings hereunto annexed show clevations partly in
section of part of the crank shaft of a steam engine with two connecting rods
working on to its crank pin, one maintained always in compression the other in
tension by the rods being connected to two concentric pistons which are by a spring
constantly drawn towards one another as above explained.
A is the cylinder of the engine-B a hollow piston open at one end-D a piston
within the piston B-B¹ a hollow piston rod extending from the piston B to the
slide block X-D₁ a piston rod passing from the piston D through the hollow
rod B' and bearing at its end against a pin Y carried by the slide block-Z a spring
interposed between the end of the piston rod B₁ and a collar on the end of the
rod D¹-B² are connecting rods coupling the pin Y with the crank pin of the crank
shaft and which are kept always in tension and D³ a connecting rod between the
pin Y and the crank pin and which is always in compression.
At Figure 3 I have shown a vertical section of a steam engine in which two
connecting rods working on one crank pin of the crank shaft are similarly kept the
one in compression and the other in tension and in which the admission of steam
to the cylinder is effected in the manner above described.
A is the fixed cylinder of the engine having working within it a hollow piston B
from which a tubular neck or piston rod B₁ extends through the inner end of the
cylinder and is coupled by connecting rods B2 with the crank pin C' of the crank
shaft C-D is an inner piston fitting within the interior of the piston B it has a
tubular rod D' extending from it which passes through the piston rod B¹ and is
connected by a connecting rod D with the crank pin Č¹.
The pins which couple the connecting rods B* D* to the piston rods B' D¹ are as
shewn at opposite sides of a central line passing through the cylinder and crank
shaft so that as the crank passes the dead centres the pistons are moved somewhat
end wise relatively the one to the other as above explained.
The end of the piston rod D' is also shewn to be enlarged and to fit as a piston
within the outer piston rod B¹ so that by the admission of steam between this
piston and the closed end of B¹ the two pistons may constantly be forced in opposite
directions and the connecting rods B₁ thereby maintained in tension and the
connecting rod D* in compression.
E is a tube extending from a steam supply chamber F at the outer end of the
cylinder A into the interior of the tubular piston rod D' and so keeping the interior
of this rod always supplied with steam-D* are openings through the end of the

page_text: piston rod D¹ by which steam is always admitted between the closed end of B¹ and
the piston at the end of the rod D¹ to act as a spring as above explained.
E E' are openings at the inner end of the steam supply tube E for admitting
steam to the cylinder A. G is a tubular cut-off valve which can be moved endwise
, and made to cut off steam from some or all of the side outlets E¹ from the steam
supply pipe. In the drawing it is shewn to be closing all the steam outlets and
thereby cutting off steam entirely from the cylinder of the engine.
The rod G¹ of the valve G passes out through a stuffing box G' and may be acted
upon by the governor or by hand as desired.
In the piston rod D¹ are steam ports D³ and in the closed end of the piston B are
ports B³. When these ports open to one another and to some or other of the steam
supply openings E¹ steam will pass to the inner end of the cylinder A and cause
the pistons to effect their out stroke.
In the drawing the pistons are shewn just at the end of the in stroke-the
pistons BD are being moved relatively the one to the other the piston B away
from the crank shaft and the piston D towards the crank shaft-the ports D³ B³
will thereby be made to open to one another and as the ports D³ are over the
steam inlet openings E¹ a way is opened for the passage of steam to the inner end
of the cylinder.
The pressure of steam then acting upon the piston B effects the out stroke-the
amount of steam admitted depends upon the position of the valve G-if it is not
covering any of the side openings E of the steam supply pipe steam will be
admitted during the whole of the out stroke but by being moved end wise towards
the shaft it can be made to cover more or less of the side openings and so effect an
earlier cut off of the steam.
For the first portion of the outstroke steam is exhausted from the outer end of
the cylinder A directly through the exhaust ports H formed through the side
of the cylinder. After a short portion of the outstroke has been completed this
direct opening to the exhaust is closed by the piston travelling beyond the
exhaust ports but a further exhaust is given through ports B' D'in the pistons B D
which then have been made to open one to the other by the relative movement
given to these pistons.
At the completion of the out-stroke the pistons are again moved relatively the
one to the other but in the opposite directions-this closes the exhaust ports B' D₁
and opens other ports B³ D³ to permit the steam in the inner end of the cylinder A
to expand into the outer end-the steam then acts against the piston D which is
of larger area than the annular surface of the piston B upon which steam is acting
to press the piston B in the opposite direction so that the pressure upon the
piston D effects the instroke and the piston B is drawn along with it by the con-
necting rod B which connects it to the crank pin.-Towards the end of the
instroke the ports D³ pass over the steam inlet openings E' in the steam supply pipe
but the ports B³ in the piston B are then not open to the ports D³ so that no steam
passes to the inner end of the cylinder until the pistons are moved relatively the
one to the other at the completion of the stroke.
In the drawing the crank shaft of the engine is shewn to be enclosed within &
closed oil chamber as is usual in other quick running engines.
The valve arrangements above described may be used for controlling the
admission of steam to and its escape from the cylinder or pair of cylinders of an
ordinary steam engine.
In this case the two parts forming the valve would be carried to and fro with
the piston of the cylinder and would in addition be moved relatively the one to the
other at each end of the stroke.
To effect this the two parts might be coupled by links to arms projecting from
opposite sides of the pin used to connect the piston rod to the connecting rod and this
pin be fixed in the connecting rod. The cut off valve hereinbefore described which
is under the control of the governor can also be used with this valve mechanism

page_text: and thereby give the advantages attending the use of a non-reciprocating cut off
expansion valve.
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. Giving motion to the crank shaft of steam or other engines by two connecting
rods working on to one crank pin the rods being moved to and fro by separate
pistons which are contained in the same cylinder and are pressed at all times in
opposite directions so that one rod is always maintained in compression and the
other in tension.
2. The means for controlling the admission and escape of steam or other fluid
from the cylinder of an engine such means consisting of the steam inlet E and
piston made in two parts which are moved relatively the one to the other at each
end of the stroke to open or close ports formed through them.
3. The combination of the steam inlet E and double piston with ports formed
in each of its parts one part coupled to a crank pin on the crank shaft of the
engine by a connecting rod which is jointed to it on one side of the centre of its
end and the other part coupled to the same crank pin by a connecting rod jointed
to the opposite side of the centre of its end so that the two parts of the piston are
moved relatively the one to the other at each end of the stroke so as to open or
close the ports.
4. The arrangement of the non-reciprocating cut off expansion valve substan-
tially as described.
5. The construction of steam and other engines substantially as herein before
described.
CARPMAEL & Co.,
Agents for the Applicant.