IMPROVEMENTS IN ENGINES TO BE WORKED BY STEAM AND OTHER FLUIDS
Year: 1852

page_text: LETTERS PATENT to Charles William Siemens, of Adelphi Terrace,
in the County of Middlesex, for the Invention of "IMPROVEMENTS
Sealed the 30th March 1858, and dated the 9th October 1852.
PROVISIONAL SPECIFICATION left by the said Charles William
Siemens at the Office of the Commissioners of Patents, with his
Petition, on the 9th October 1852.
I, CHARLES WILLIAM SIEMENS, of Adelphi Terrace, in the County of
Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN ENGINES TO BE WORKED BY STEAM AND OTHER FLUIDS"
to be as follows:-
My improvements in engines to be worked by steam and other fluids
consist of combining a working cylinder (which with its working trunk,
respirator plates, and heating vessel is identical with or similar to the
working cylinder of the regenerative engine for which I obtained Let-
ters Patent on the 22nd December 1847, with a plain charging cylinder,
which, assuming the functions of the regenerative vessels and compound
valve of the former engine, serves alternately to charge and discharge

page_text: the working cylinder in order to impart motion to the working trunk,
and hence to the crank of the engine.
The position of this crank of the charging cylinder is at right angles
or nearly so to that which receives motion from the working trunk, so
that the charging piston may effect its upward stroke while the crank
of the working trunk is passing over its bottom centre, and its down-
ward stroke while the latter is passing over its top centre. A valve of
the form of an ordinary three-ported slide valve is provided, the central
port of which communicates to the cylinders, another to a small boiler,
and the third to the atmosphere or to a condenser. The space between
the ports is greater than usual, in order that the communication
between the cylinders and the boiler on the one hand, and the
atmosphere or condenser on the other hand, may only be established for
short intervals of time, while the charging piston is an old top and
bottom centre respectively.
A pump forces a jet of water into the passage between the cylinder
during each downward stroke of the charging piston; the mouth of the
injection pipe is covered by a weighted valve, which causes the water
to issue in a divided spray. A groove is cut into the internal surface
of the charging cylinder to admit any water accumulating upon the
upper surface of the piston into the lower part of the cylinder, from
whence it is discharged by a cock. The bottom port of the charging
cylinder may be connected to a second working cylinder connected to
the main shaft by a crank opposite to that of the first working
cylinder.
In order to start the engine a fire is kindled under the heating
vessel or bottom of the working cylinder until its temperature is raised
to from 600° to 800° Fahrenheit. At the same time steam is generated
in the boiler either by the same or by a separate furnace.
If only one working cylinder is used the charging piston must be
moved near the top centre previous to starting, which is accomplished
by moving the slide valve by the hand gear to the steam side, when
the steam from the boiler will enter the working cylinder and force the
trunk upward through its stuffing box. In the meantime the slide
valve is to have been connected to the engine gear, and the influx of

page_text: In
steam from the boiler will have been shut off. When the moving
trunk has nearly completed its upward stroke the charging piston
commences to descend rapidly, and provides a vacuity for the steam in
the working cylinder to expand into. Before the charging piston has
reached the bottom the slide valve will have moved to the exhaust port,
which causes an additional diminution of pressure. The working
trunk thereupon effects its downward stroke merely by its own weight,
which may be assisted by a partial vacuum if a condenser is applied.
Before it reaches the bottom the charging piston begins to reascend
rapidly, and the exhaust port of the slide valve being shut by this time
the steam contained in the charging cylinder is compressed into the
annular space between the working trunk and its surrounding cylinder,
the pressure being equally raised below the working plunger (which
plunger moves quite freely within the cylinder), the trunk is moved
upward into the atmosphere, and the steam which filled the annular
space above has to expand into the entire space below the plunger.
effecting its passage through the narrow spaces between the respirator
plates it takes up heat therefrom, and in passing finally between the
internal ribs of the heating vessel its temperature is raised sufficiently
to increase its elastic force in the same proportion as it is diminished
by the increase of space. Hence, the pressure remains uniform during
the ascending stroke, although no steam should have been admitted
from the boiler. The charging piston descending, the stean returns
through the respirator, and by degrees deposit the free heat which it
had taken up in descending, and finally reaches the passage between
the cylinders only some 20° or 30° hotter than when it first entered.
In meeting the spray of injected water the steam takes up a portion
thereof at the expense of the free heat, and is brought back to its state
of saturation. The quantity of steam thus formed is discharged at
the termination of each stroke, and constitutes the only consumption of
heat of the engine. In order to stop the engine the slide valve is
disconnected from the engine gear, and left with the exhaust port open
from cylinders to the condenser or into the atmosphere. The speed
and power of the engine is regulated by lengthening or shortening the
connecting rod working the slide valve, and which is done by a suitable

page_text: governor or by hand; the effect of this is that the slide valve is altered,
whereby the the exhaust port opens more or less at the termination of
cach stroke, which regulates the working pressure. In respect of the
charging piston, it will be observed that it receives as much power (or
slightly more) in descending by the expanding steam as it takes back
in compressing the same steam into the working cylinder.
The bottom part of the working cylinder or the heating vessel is cast
with ribs projecting inward in order to increase the heating surface in
contact with the steam. The joint between the heating vessel and
working cylinder is made by a ring of copper, which is screwed between
the flanges.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles William Siemens in the Great Seal
Patent Office, on the 9th April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
CHARLES WILLIAM SIEMENS, of Adelphi Terrace, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of October, in the year of
our Lord One thousand eight hundred and fifty-two, in the sixteenth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Charles William Siemens, Her special licence
that I, the said Charles William Siemens, my executors, administrators,
and assigns, or such others as I, the said Charles William Siemens,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN ENGINES TO BE WORKED BY STEAM AND OTHER FLUIDS,"
upon the condition (amongst others) that I, the said Charles William
Siemens, by an instrument in writing under my hand and seal,

page_text: should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Charles William Siemens, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof (that is to say):
The chief part of my improvements consists of combining a working
cylinder (which with its working trunk, respirator plates, and heating
apparatus is similar to the working cylinder of the regenerative engine
for which I obtained Letters Patent on the Twenty-second of December,
One thousand eight hundred and forty-seven,) with another cylinder,
which, by the motion imparted to its piston by means of a crank
standing in an angle of 90° or thereabouts in advance of the working
crank, assumes the functions of the regenerative vessels and compound
valve of the above-named engine, of alternately charging and discharging
the working cylinder. This cylinder I propose to term the regenerative
cylinder.
My improvements consist, moreover, in a peculiar arrangement of
heating apparatus, whereby great strength to resist pressure at high
temperatures, and large development of heating surface in a narrow
compass, are obtained.
They consist, moreover, in certain methods of governing the power
and velocity of the said engines, and of reversing the motion of the
same; and, finally, in certain mechanical arrangements whereby the
engine is made double acting, and rendered applicable to locomotive
purposes.
But in order that my Invention may be more fully understood, and
readily carried into effect, I will now proceed to describe the best mode
or modes I am acquainted with of performing the same. Sheet I.
represents a sectional elevation, and Sheet II., Figure 1, an end view,
partly in section, of my improved engine. A, and A', are two working
cylinders, which are identical in construction, but, as shown, the one is in

page_text: section and the other in front.
The lower portions H, of each outer
cylinder is cast separately, and constitutes the heating vessel, the
'peculiarities of which will be more fully explained hereafter. The
internal cylinder (b) is also composed of two parts joining at (c), and is
supported in its central position by longitudinal wedges or packing strips.
The lower portion of the cylinder (6) abuts, with its projecting rim
near (c), against internal ribs of the heating vessel (see Figure 3,
Sheet II.)
The remaining annular space between the two cylinders and between
the points c and e, contains strips of brass or other metal, which are
placed upright and parallel to each other, with intervening spaces,
forming a great number of narrow channels through which the steam
or other fluid has to pass. The breadth of these channels is determined
by small projecting ribs upon every alternate strip, as shown by a full
sized section through some of the strips in Figure 2, Sheet II. The
cylinder (6) contains a deep working plunger P, which is cast hollow,
and is filled with charcoal, cinders, or other light material which is a
bad conductor of heat. The lower portion of the plunger is made
perceptibly less in a diameter than the cylinder, to allow for its greater
expansion by heat. An open brass ring (p), which is inserted in a
recess, fits the cylinder sufficiently close to serve as a light packing. A
hollow trunk T, is firmly attached to the plunger P, and reaches
upward through a stuffing box in the cylinder cover. The central
cylinder (C), (or regenerative cylinder,) which contains a working piston
(Q), communicates from its upper extremity, through the passage D, to
the working cylinder A, and from its lower extremity, through the
passage D', to the working cylinder A¹. These passages are periodically
intercepted by slide valves V and V₁, respectively, which are worked
by excentric or cams E and E', upon the main shaft of the engine.
Transversely upon the passage D, is placed a three-ported side valve
W, which is shown separately in section by Figure 4, Shect II., the
central port (f) of which leads into the same; the second port (g)
toward the boiler (which is not shown in the Drawing); and the third
(h) into the condenser F, through the pipes k. The distances between
these ports are much greater than in ordinary slide valves, for the purpose

page_text: of giving dead traverse to the valve. The areas of the ports are very
small as compared to that of the main passage between the cylinders.
The slide (1) is worked to and fro by the parallel motion rods of the
regenerative cylinder, and by the rods (m) and (n), and bell crank
lever (o) (see Sheet II. Figure 1.) A second slide valve W, is
situated upon the main passage D', which is worked in the same
manner, and differs from the first only in the relative position of the
ports g and h, so that the central port of the one is opened to the
boiler, while that of the other is opened to the condenser, and vice
versà. A double-acting force pump (G) is provided, which is worked
by the parallel motion rods of the regenerative cylinder (as shown in
Figure 1, Sheet II.), and serves to inject water into the passage D,
through the weighted valve (v), during the descent of the piston Q,
and into the passage D', through a similar weighted valve v¹, during
the ascending stroke of the piston Q. The working trunks T and T¹,
are connected to crank pins p and p', (in the driving wheels of the
engine,) by means of connecting rods and guide levers, which will be
sufficiently well understood from the Drawing. The two crank pins
are placed exactly opposite to each other, so that the one trunk may be
in its lowest position while the other occupied the highest, and the one
make its ascending while the other completes its descending stroke.
The piston of the regenerative cylinder is worked by a double crank q,
in the main shaft, which is placed at an angle of 95° or thereabouts
in advance (in the direction of the motion) of the crank pin p.
The condenser F, I prefer to be of the description called surface
condensers, in order to obtain pure water of condensation to supply the
injection pump. The air pump and hot well are not shown in the
Drawing, as their entire arrangement may be as usual.
The lower part H, of the working cylinders or "heating vessel" is
shown separately in section, and on an enlarged scale, by Figure 3,
Sheet II. It is a strong cast iron vessel, with internal ribs diverging
from the centre, and presenting a very extended surface to the steam
(or other fluid) which passes between them and the internal cylinder
(b). The heating vessel is bolted to the cylinder, and a tight joint is
formed between them by means of a ring of copper, which is secured in

page_text: between their faced edges, fitting partly into annular grooves. The
advantage of this joint is that it will hold tight at very elevated
temperatures.
The heating vessel is surrounded by a fire which circulates through
the flues a, a, which also surround the cylinder A, itself, to heat the
lower portions of the metallic strips, thence proceed under a boiler, and
finally issue into a chimney.
Previous to starting the engine the temperature of the heating vessels
is raised to from 600 to 800° Fahrenheit, which temperature may be
ascertained by suitable pyrometers, and steam is generated in the boiler.
If the lost heat of the fires after leaving the heating apparatus should be
found insufficient for the latter purpose a separate fire place must be
provided for the boiler. A three-way cock Z, for cach cylinder is opened
to admit steam through the pipe y, which leads to the bottom of the
heating vessel. The slide valve (W) is moved by means of the hand lever
x, into the position shown in Figure 4, Sheet II., allowing the steam to
pass to the condenser, and blowing through that into the atmosphere.
The heat which the steam takes up in the heating vessel serves to elevate
the temperature of the respirator strips to above that of saturated steam,
but in a less degree toward the upper extremities than toward the
bottom. The air is moreover expelled from the cylinders and the con-
denser. The cock Z, is then shut, and supposing the piston Q, to stand
near its top centre, the valve W is moved to admit steam from the
boiler to the working cylinder A, and is thrown into gear with the engine
by means of the hand lever and catch 1. The steam, in filling the entire
vacancy of the working cylinder A, and being unable to exert its force
upon the piston Q, which I supposed to stand nearly upon its dead centre,
will force the trunk T, upward. In doing so the steam which was at
first received in the annular space between the trunk and the cylinder
(6), (and which I prefer to be about equal in area with the trunk itself,)
will circulate freely through the respirator and between the ribs of the
heating vessel into the larger space which is forming below. In taking
up heat in its passage its temperature is raised from, say, 275° Fahrenheit
(the temperature of saturated steam at 3 atmospheres pressure) to, say,
650° Fahrenheit, whereby its expansive force will be increased in about

page_text: equal proportion with the space, and consequently the pressure will be
maintained during the ascending stroke without additional influx of steam
from the boiler. The position of the crank pin (p) being nearly over
right angles with that of the crank ( ), the trunk T will complete out
5/6th parts of its stroke before the piston Q has moved far over its dead
point. It now commences, however, its descending stroke, in which it is
aided by the steam contained within the working cylinder A, which will
by its expansion be rapidly reduced in pressure, the influx of steam from
the boiler being stopped by this time. In passing upward through the
respirator the steam yields back its sensible heat to the metallic surfaces
in the following manner; that is to say, the temperature of the steam
being raised by the heating vessel slightly above that of the bottom
edges of the metallic strips will, on entering between them, part with a
portion of its heat. In proceeding upward it will meet with cooler
surfaces, and yield additional heat, and by continuation of this process it
will reach the upper extremities of the metallic strips at little more than
their own temperature, which by the previous descending current was
reduced to that of saturated steam. The heat thus given up to the
metallic surfaces will be taken up by the succeeding descending current,
and will in this manner be worked over and over again, sustaining each
time certain losses (proportional to the heat which becomes latent in
the expansion of the steam, and to the imperfection of the apparatus
employed). Before it reaches the regenerative cylinder the steam meets
the divided spray of injection water through the weighted valve (v),
which reduces its temperature more fully to the point of saturation in
forming fresh steam with its excessive or free heat. In proportion as
the refrigeration proceeds the steam is again contracted, and in filling
the regenerative cylinder its pressure is reduced nearly in proportion
as the annular space between the working trunk T, and the surrounding
cylinder is to that space plus the capacity of cylinder (C); or supposing
the capacity of the latter to be equal to three times the annular space,
it follows that the pressure will be reduced to about 1/4". Immediately
before the downward stoke of piston Q is completed, the valve (V) is
shut; and at the same instant the valve W opens a communication
from the working cylinder to the condenser. The pressure within

page_text: the working cylinder will thereby be still further reduced, and the
working trunk will effects its downward stroke by the pressure of the
atmosphere in excess of the remaining steam pressure assisted by its
own weight. In the meantime the piston Q, traverses over its lower
turning point, and having barely commenced its ascending stroke the
valve V opens, and simultaneously W is closed. The pressure upon
the piston Q, will be partially relieved by the expansion of the steam
into the annular space of the working cylinder; but in compressing the
entire contents of cylinder C into the same during the ascending stroke
it will encounter a resistance nearly equal in amount with the impetus
which it received in its descent. Meanwhile the working trunk T, has
passed its lower turning point, and makes its ascending stroke, with the
compressed steam contained within the annular space, as before described.
The pressure is slightly augmented by an influx of steam from the boiler,
which is established during that period, and while the piston Q, is nearly
at rest upon its top centre. The valve W', having also been thrown into
gear with the engine at its starting, the second working cylinder A', will
in the meantime have received a charge of steam, which will have ex-
panded into the regenerative cylinder, urging the piston Q upward with
a force exceeding the opposing pressure, and the working trunk T", will
have made an effective stroke in the same manner as described with
regard to T, but ascending while the other was descending, and vice
versa. It would be impossible so to regulate the supply of injection
water that it would all be absorbed into the steam by its uncombined
heat. Means must therefore be provided to prevent the excess from
accumulating, and this is accomplished by providing small cavities 4, 4, 4,
in the side of the regenerative cylinder, into which the water upon the
piston will enter in its ascent, and upon the piston having passed by it
will drop to the bottom, whence it is discharged through a small cock
(5). I regulate the power and velocity of the engine by either aug-
menting or decreasing the amount of steam which is worked to and
fro between the regenerative and working cylinder. For this purpose
the pressure within the boiler is maintained at its greatest height,
and the traverse of the slide valve W (and W') is made only sufficient
to open the inlet and outlet ports partly. The valve rod (n) is made

page_text: in two parts, upon the ends of which a right-handed and a left-handed
thread is cut, which are screwed partly into right and left handed
female threads of a bush (6). A cord pulley (7) is worked to and fro
by the governor (which I prefer to be the chronometric governor,
having a pulley placed upon the arm of its differential wheels, by which
means its traverse is increased ad libitum), whereby the rod m, is either
lengthened or shortened. In the first case the slide valve will open the
port leading from the boiler more fully, while the exhaust opening will
be contracted, and the result will be an increase of power; by shortening
the rod the opposite effect will be produced. The same object may be
attained by introducing throttle valves both into the steam and exhaust
pipe, and attaching the governor to them in such manner that the one
is open when the other is closed, and vice versa.
The object of putting the crank of the regenerative cylinder slightly
more than 90° in advance of the working trunk is to commence with
drawing the steam from the working cylinders considerably before the
ascending stroke is completed; a portion of the steam is thus saved from
being heated, and an advantage is gained which corresponds very much
with the saving by expansion gained in ordinary engines.
Sheet III. exhibits another arrangement of my improved engine,
which I prefer in cases where speed and lightness are important deside-
rata, and especially for locomotive purposes. Figure 1, is a sectional
elevation of the same; Figure 2, an end view, imagining the first
engine up to the line a, y, in Figure 1, to be removed. Figure 3, is
the plan of the engine. A, and A', are the working cylinders, which
are placed horizontally and opposite to each other on either side of the
cranked driving shaft (S). The working trunks T, and T", are rigidly
combined by means of four stay rods a, a, a, a, which allow of the
working of the crank (S) between them; in one of the trunks a con-
necting rod (r) is secured. A second connecting rod (t) is attached
to the same crank pin with (r), and serves to impart motion to the
piston Q of the regenerative cylinder C. The construction of this
cylinder is made similar to that of an ordinary trunk engine for the pur-
pose of economising space. The angular position of the regenerative
cylinder is such that its piston reaches its half stroke shortly before the

page_text: working trunks arive at their extreme positions in the ordinary work-
ing of the engine. The deviation of its axis from the perpendicular
(or its lead) should be greatest in engines working at high speeds, and
may be increased to 20 or 30°. Two passages D, and D', lead from
the regenerative cylinder to the working cylinders. The heating vessels
H, and H', differ in form from those above described, in as much as
their bottom surface is deeply indented for the purpose of encreasing
the heating power. Radial ribs (ff) cover the entire inner surfaces,
and the internal cylinder (b) reaches down between them to direct the
current of the steam. The respirator plates occupy the annular spaces
(c, c). F, and F, are the furnaces, consisting each of slanting bars
d, d, d, and a hopper e, which is filled with fuel, and supplies the
furnace by gravity. The brick arch (i) is perforated to supply air for
the consumption of smoke, the air being admitted through the regu-
lating door (1) and passage (m). The fire passes through the channel
(n) into the cavity (or fire box) of the heating vessel, whence it spreads
to all sides, as indicated by arrows. At the extremity of the
cylinders the current reverses its direction, and passes through the
annular channels (0, 0), the external surface of which is the inner tube
surface of a boiler B. The fire finally reaches the flue (p), and thence
the chimney. The intervening cylinder between the channels (n', n¹,)
and (0, 0) is made of or lined with fire brick, and is supported at
intervals by longitudinal ribs or feathers of brick or iron from the
boiler; the draught of the fire is regulated by a door (g) in front of the
ash pit; its access to the heating vessel may, moreover, be stopped
entirely by lowering the damper 1. The working cylinders are
bolted to the fronts of the boilers, which in their turn are bolted
down upon the framing R of the engine, which also supports the
main bearings of the shaft S, as will be understood by inspection
of the Drawing. Steam pipes s, s, lead from the boilers into the
box of an ordinary three-ported slide valve W, which is attached
to the regenerative cylinder. The central port of this valve leads
to the exhaust pipe (t), another to the upper extremity, and the
third to the lower extremity of the regenerative cylinder. A link
motion similar to that commonly adopted for locomotive engines is

page_text: provided, which is worked by the two excentrics (u) and (v),
and is regulated by means of the hand lever (w). Two additional
valves U, and U', are provided, which are both of them attached to
the same hand lever (w) by the levers and rods marked (2).
They serve to reverse the engine by interchanging the communi-
cation with the working cylinders with the top and bottom of the
regenerative cylinder respectively. Four set screws marked 1, serve
to approach the plate 2, against the back of the slide of either valve,
so that the latter is held up against the port, and prevents both
the egress and regress of steam. A double-acting force pump has to
be provided (but which is not shown in the Drawing) to inject
water into the passages D, and D', through small rose heads or jets 3,
and 31, at proper intervals, as before described. The excess of injection
water is got rid of by cutting a groove or forming cavities in the side
of the regenerative cylinder, as shewn at 4, which will cause it to
collect in the bottom, whence it will be expelled with the waste steam.
The boilers should be provided with all the usual appendages, such as
safety valves, guages, &c. The working of this engine is in principle
the same as before described. When standing, the hand lever (w)
should occupy its perpendicular position, to insure that the slide valve
(W) covers its three ports, no matter in what position the excentrics
stands. Previous to starting the engine the fires must have raised the
temperature of the heating vessels to from 600 to 800°, and have
generative steam in the boilers. The piston Q, moreover, must nearly
occupy either of its extreme positions; on drawing the hand lever
(w) into the position as shown the incline of the link motion will
move the valve (W) into the extreme position of the proper excentric,
and admits steam into one of the working cylinders, the valves U and
U having by the same motion assumed their extreme positions. The
working trunks will then make their stroke, and commence their reci-
procal action with the regenerative cylinder. The side valve alternately
admits steam from the boilers, and discharges the same into the atmo-
sphere (or a condenser) at the proper intervals from both the working
cylinders. The passages D, and D', remain uninterrupted in the
working of this engine.

page_text: Sheet II., Figure 5, shows another arrangement of my improved
engine. It consists of a working cylinder A, the piston P of which is
attached to the same piston rod with the piston p of another cylinder
T, of from one half to two thirds the area of the former. The lower
end of cylinder T, communicates to the upper end of cylinder A, and
the upper end of the former to the lower end of the latter through
passages D, and D', which are enlarged toward the bottom, forming
chambers R, and R', which contain metallic substance presenting a
large developement of surface (being either plates, copper turnings, wire
gauze), and fulfil the function of respirators. C is the regenerative
cylinder, which communicates at both extremities with cylinder T.
The piston Q of this cylinder works on a crank standing over a right
angle or thereabouts with that of the working piston. A fire place
F, serves to heat the working cylinder to from 500 to 600° of
Fahrenheit, and to raise steam in a boiler. The piston Q being
near its lower position, steam is admitted below it, and in filling both
the spaces below the piston p, and above the piston P, through the
respirator (R), forces them downwards with a power of the pressure
multiplied by the difference of area between the pistons (P) and (p);
the pressure will be maintained during stroke (independent of a supply
from the boiler) by the increase of temperature which the steam receives
in its passage from the smaller into the larger cylinder. The stroke
being nearly accomplished, the pressure is reduced by the combined
efforts of the respirator, the injection (which is not shown), the regene-
rative cylinder (expanding it three or four fold), and of the exhaust
valve; the same action is repeated on both sides of the piston. The
piston P has in this case to work steam-tight in its cylinder, and
for that purpose the steam should be more moderately heated than in
adopting the forms of construction before described.
It will be readily perceived that my improved engine may be worked
also by air (or other permanently elastic fluid). An air reservoir must
in that case be provided for the purpose of starting the engine, and the
abstraction of the waste heat has to be effected by external application
of cold water or current of air to the regenerative cylinder and working
trunks, or by the circulation of cold water through pipes traversing the

page_text: passages
of the air, or by similar means. It may, however, also be
worked by both air and steam conjointly, either by forcing continually
small quantities of air into the cylinders, and which offers some
advantage in retarding actual condensation of the steam by contact
with the exposed regenerative cylinder, or they may be used conjointly
in maintaining the regenerative cylinder at a temperature below 212°
Fahrenheit (by external refigeration or by the introduction of cold
water), and filled with air, and by introducing divided jets of water
into the current of the air on entering the respirator plates, which
will then assume the double function of first converting the water
into steain, and immediately afterwards raising the temperature of
that steam (together with the air which accompanies it), and in its
return of first cooling and afterwards condensing the same. Instead
of air, vapours of a lower boiling point, such as chloroform, sulphuretted
carbon, may be introduced in a liquid form with the steam.
Having now described the nature of my Invention, and the best
modes I am acquainted with of performing the same, I wish it to be
understood that I do not claim the use of the respirator or of the
working trunks separately, nor do I confine myself to any of the
letails herein given; but I claim the combinations or modifications of
engines herein described.
In witness whereof, I, the said Charles William Siemens, have
hereunto set my hand and seal, this Ninth day of April, in
the year of our Lord One thousand eight hundred and fifty-
three.
CHARLES WILLIAM SIEMENS. (L.S.)
Witness,
JAMES G. JONES.