CERTAIN IMPROVEMENTS IN ENGINES TO BE WORKED BY STEAM AND OTHER FLUIDS, AND IN EVAPORATING LIQUIDS
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
WILLIAM SIEMENS, of Birmingham, in the County of Warwick, Engineer,.
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twentieth day of
March, One thousand eight hundred and forty-nine, in the twelfth year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles William Siemens, my exors, adññiors, and assigns, Her
especial licence, full power, sole privilege and authority, that I, the said
Charles William Siemens, my exors, adiñors, and assigns, and such others
as I, the said Charles William Siemens, my exors, adñors, or assigns, should
at any time agree with, and no others, from time to time and at all times
during the term of years therein expressed, should and lawfully might make,
usc, exercise, and vend, within England, Wales, and the Town of Berwick-
upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS IN ENGINES TO BE
WORKED BY STEAM AND OTHER FLUIDS, AND IN EVAPORATING LIQUIDS;" in which
said Letters Patent is contained a proviso that I, the said Charles William
Siemens, should cause a particular description of the nature of my said Inven-
tion, and in what manner the same is to be performed, by an instrument in
writing under my hand and seal, to be inrolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after the
date of the said in part recited Letters Patent, as in and by the same, reference
being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles William Siemens, do hereby declare that the nature of my said

page_text: Invention, and the manner in which the same is to be performed, are fully
described and ascertained in and by the following statement thereof, reference
being had to the Drawings hereunto annexed, and to the figures and letters
marked thereon, that is to say:-
The first part of my Improvements in Engines to be Worked by Steam and
other Fluids, and Evaporating Liquids, consists in a certain method of con-
densing the steam of steam engines (after it has served to propel the piston,
within the working cylinder, either wholly or only in part, allowing the
remaining portion to escape into the atmosphere, and in such a manner that
the water employed for effecting such condensation issues from the condenser
at its boiling point or nearly so, but nevertheless produces a vacuum within
the cylinder. In order that this part of my Invention may be most fully
understood, and readily carried into effect, I will now proceed to describe
.the best arrangements I am acquainted with for effecting the same.
"
Sheet I., Figures 1, 2, and 3, represent my improved condenser, which I
propose to term "a regenerative condenser" on account of its analogy in
principle to the regenerative engine, as described by me in the Specification
of my Patent dated December Twenty-second, One thousand eight hundred
and forty-seven.
Figure 1 shews an elevation in section of the same, together with the cylinder,
the valve casing, and portion of a beam of a low-pressure condensing engine
whereto it is attached; Figure 2 shews a plan with the cover 9 and a portion
of the plates B removed; and Figure 3 an end view of the condenser only.
It consists of a casing A, which contains the metal plates B of a cylinder C,
with its piston P of the valves V and v, an injection pipe I, with its injection
valve or cock a and discharge valve 6, and of the combination of rods and
levers F which communicate motion to the piston P. The upper end of the
casing A is directly connected with the exhaust passage p of the engine.
This casing communicates freely with the lower end of cylinder C through
the passage c, and with the upper end of that cylinder through the valve V,
the opening whereof is limited by a spring d, which also serves to accelerate
its reshutting. The plates B, which I prefer to be of copper as being the
best conductor of heat among the cheaper metals, and at the same time
possessing a good capacity for heat, are made of various lengths and thickness
in direct proportion to the length of stroke of the engine. In this case
they are made parts of an inch thick, and twenty-four inches long each,
the length of stroke of the engine being four feet six inches, and of such a
breadth as to fit the casing A. They are placed parallel to each other, and
are held a certain distance (about equal to the thickness of the plates them-
selves) apart by means of small washers (or clse longitudinal strips of

page_text: metal e, e, e), and are fastened together by means of screw bolts with shallow
heads and nuts e, e', which pass through holes in the plates and the washers
(or strips) e, e; e. A. bent. wire or band of metal (a) is fastened to the upper
ends of the plates so as to form a. loop for the convenience of removing them.
The whole pile or package of plates fits the sides of the casing A, and it rests
upon the upturned edges of the strong perforated plate f.
Figure 4 represents an enlarged section of the plates and casing at a*, *,
also with a portion of the plates removed in order to expose the perforated
plate fand the injection discharge valve b. A lid g covers the open top of
the casing A, which must be taken off in order to gain access to the plates B
and the valve V. The piston P is made of considerable length, hollow inside,
but closed hermetically, and packed with hemp or metallic rings at its lower
extremity; it receives its motion from the engine through the medium of the
two connecting rods (h, h), the levers i, i, and k, k, the connecting rods 1, 2,
and the cross head m, with its guide rollers n, n, which play within the
guide frame o, and insure the perpendicular motion of the piston rod q. The
vibratory motion of the levers h, k, and the rods I, 1, causes the piston P to
complete two strokes for every one stroke of the engine, which will be readily
understood on inspecting the Drawing. The action of this condenser is as
follows: The passage c and the cylinder C below its piston are filled with
cold water which is continually supplied through the injection pipe I. If the
piston P descends, it displaces the water from cylinder C, and causes it to
ascend between the plates P until it finally issues in a divided state into the
uppermost portion of the casing A. At this instant the exhaust port of the
engine opens and allows a volume of steam, of the maximum pressure at which
it is discharged from the steam cylinder, to pass through the pipe p and the
valve V into the cylinder C (which at the time is quite empty, the piston P
being in its lowest position), and to carry with it all permanent gases and
water which may have accumulated in the upper portion of the casing above
the plates B. While this partial discharge of the steam cylinder takes place,
the piston P passes its dead point of motion, and commences its upward
stroke, the water is thereby drawn back from the casing A, its level descends
and exposes at first only the upper ends, but gradually the entire surfaces, of
the plates B to the steam, which continues to flow in above from the steam
cylinder. The steam, coming in contact with the upper ends of the plates,
will rapidly condense until their temperatures are nearly equalized. In the
meantime an additional and colder portion of the plates B will emerge from
the descending water, and further condensation take place, until by degrees
the lowest and coolest portion of the plates will become exposed and condenso
о

page_text: the (through continued condensation) already much expanded steam. The
whole latent heat of the steam thus condensed is absorbed by the plates B,
which thereby will have become very unequally heated, their temperatures at
the upper ends being equal (or nearly so) to that of the steam in the state of
its bighest pressure at which it was discharged from the cylinder (or nearly
one hundred and twelve degrees Fahrenheit, if the steam is discharged at
.atmospheric pressure), and at their lower ends equal (or nearly so) to the
temperature of the most expanded steam (or nearly one hundred and
twenty degrees, if the vacuum within the cylinder is equal to a column of
mercury of 26.5 inches). The vacuum will be rendered still more perfect
when the water level descends below the mouthpiece of the injection
pipe I, and the steam comes in immediate contact with the cold injected
water. The piston P has reached its highest position and the water in A
its lowest level when the piston in the steam cylinder has completed half its
stroke. During the remaining half stroke of the engine the piston P again
completes its downward stroke, and the water again ascends between the
plates B, continually absorbing heat therefrom, until it issues into the upper
portion of the casing A, at a temperature little inferior to that of the upper
ends of the plates themselves. At this moment a fresh discharge of steam
from the engine takes place, and carries all the water which is projected
beyond the upper edges of the plates B (and which must be equal in amount
to the water injected, since the previous discharge plus the condensed steam)
together with the fresh accumulation of permanent gases along with it into cylin-
der C. The water in mixing with the hot steam will at the same time receive
an additional increase of temperature. The piston P immediately afterwards
again ascends, and withdraws the water from between the plates, which, being
sufficiently cooled by the discharged water, again effect a vacuum within the
working cylinder of the engine in the same manner as above described. The
steam, water, and permanent gases which escape into the cylinder C every
.time the piston P is in its lowest position, are discharged during the ascent of
that piston through the valve into the hot well H, from whence a portion
of the water goes to supply the boiler, and the remainder is rather wasted,
or, being nearly boiling hot, may be used advantageously for heating
buildings, for bleaching, washing, or other useful purposes. The object of the
perforated plate is, besides supporting the plates B on its raised edges, to
divide or equalise the current of water in its progress from the cylinder C to
the casing A, and vice versa.
It will be readily perceived that this condenser is equally applicable to
engines of different construction, and which are worked by steam of various

page_text: lensity or pressure, extending even to that class which are commonly called
high-pressure or non-condensing engines, but if applied to the latter it admits
of considerable simplification, which will become apparent from the following
lescription:-
Sheet I., Figures 5, 6, and 7, represent a condenser on my improved prin-
ciple, which I prefer to apply to high-pressure engines. Figure 5 is a sectional
elevation; Figure 6, an end view Figuro 7, a plan of the same with the
cover g and portion of the plates 6 removed. It consists of a casing A. con-
taining the plates B of a cylinder C with its piston P of the injection pipe I
furnished with a regulating cock and discharge valve, and of the valve V.
The only essential difference between the condenser and the one already de-
scribed consists in the omission of the valve v, sec Figure 1, and in closing the
end of cylinder C, whereby a vacuum is always maintained between the cover r
and the piston P. The piston receives its motion from the engine through
the medium of gearing or any other suitable contrivance which will cause it to
make two strokes for every one stroke of the engine. In consequence of this
motion water alternately ascends and descends between the plates B, which
water is supplied by the injection pipe I. The waste steam of the engine
enters the condenser through the discharge pipe p at the moment when the
water overflows the plates B, and being of superior pressure to that of the
atmosphere, it throws the valve V open, and issues into an open cistern,
carrying with it all water and air which has collected in the chamber above the
plates. The valve V will remain opened until the pressure of steam within
the steam cylinder is reduced to that of the atmosphere, when its own weight,
assisted by the spring & and the back pressure which will immediately after
arise, will close it again. The water level between the plates will in the mean-
time have commenced to recede, and the remaining atmosphere of steam in
the cylinder will be condensed in the same manner as already described. Any
air or water which may leak into the vacuum side of cylinder C is allowed
to escape through a small discharge valve w in the piston P.
Sheet I., Figures 8, 9, 10, and 11, represent an application of my improved
condenser to a pair of locomotive steam engines. Figure 8 is a side elevation
of the condensers, with part in section, shewing also their moving gear and
portions of the engines themselves; Figure 9 is a plan of the condensers in
connection with the cylinders of engines; Figure 10 is a sectional front view
of the condensers, shewing also the front of the engines; and Figure 11, a
plan of the condensers only, with the covers removed in order to expose the
plates and valves to view. All parts constituting the condensers are colored,
whereby they can be readily distinguished from parts of the engine as pre-

page_text: viously existing, which are are left in outline. There is no essential difference
in principle between these condensers and the one just described, but they are
.clifferently constructed on account of conditions of speed and locality peculia
to the locomotive engine. They are cast in one piece, and may be place
either between the cylinders of the engines I. and II. (if they are placed :
sufficient distance apart), or in front of them, as shewn in the Drawing. This
casting consists of two short cylinders C and C', which are open at their
bottom, and extend upward into rectangular chambers A, A, which contain
the sets of plates B and B'. The exhaust ports of the engines communicate
separately with A and A¹ through a double passage p, p', which is provided
with two longitudinal apertures 4 and q¹. These apertures are covered by
two double lip valves V and V, which are generally closed, but which afford
to the steam within the steam cylinders an exit into the blast pipe G.
Each valve consists of two rectangular leaves r, r, which turn upon centre
pins, and rest (if closed) at their ends upon triangular piers t, t, but at
the same time touch one another with their upper edges, and form a steam-
tight covering to the aperture q and q'. The opening of the leaves is limited
by springs u, u, u, which also accelerate their motion in shutting. The con-
densers are provided with a second pair of valves w and w¹, which always
open and shut simultaneously with V and V¹, and discharge the water and air,
together with some steam, into the hot-water cistern H, while the principal
portion of the exhausted steam passes into the blast pipe G. The pistons P
and P are connected with the opposite ends of a vibrating lever v, and
cause water to ascend and descend alternately between the plates B and B',
whereby the condensation of the one atmosphere of steam (which remains
within the working cylinders after the discharge into the blast pipe G and the
cistern H has taken place is effected) cold water is continually injected in a
divided state immediately below the plates B and B', through the injection
pipe J which proceeds from the tender of the engine. A cock regulates the
flow of the injection water. The hot water which is continually discharged
into the cistern H, serves to supply the feed pumps for the boiler through the
pipe 1. Any excess of water, together with the steam and air which the con-
densers eject, is allowed to escape into the atmosphere through the overflow
pipe a, the entrance whereof is throttled by a conical plug valve 6, which is
regulated by a screw and handle c, and has for its object to limit the
quantity of steam ejected through the valves w and w¹, in order to save
as much power as possible for the blast. The pressure thus created within the
cistern H also assists in forcing the hot feed water towards the pumps. The
plates B and B are fixed in their position by means of wedges or set screws,.

page_text: and are much thinner than those which I prefer for stationary engines. The
contrivances which I have adopted for communicating a vibratory motion
to the lever and shaft v, consists of a double segment d, between the sides
whereof moves a stecl roller e, which is slipped upon a pin at one end of the
cross head of the engine I. The segment is rigidly connected with two bell-
cranked levers and f¹, which are between themselves combined by a rod 9,
and therefore permit the former no other but a parallel up and downward
motion, which it acquires in consequence of the horizontal movement of the
cross head and roller c. The lateral thrust against the segment is sustained
by fixed rollers h and h'. The motion thus imparted to the segment is
conveyed to the shaft v, and hence to the pistons P and P¹, by means of a con-
necting rod i, which combines the bell-crank lever f and a lever upon the
shaft v.
Onc motion is sufficient for both condensers, if the engines act upon
cranks which form an angle of ninety degrees, the one with the other, but if
that angle is changed it becomes necessary to work the piston of each
condenser by a separate motion.
I shall now proceed to enumerate the principal advantages which I expect
to gain by the application of my improved condenser A, with reference to low-
pressure engines.
First, a much smaller quantity of condensing water suffices to effect a
vacuum within the steam cylinder than would be necessary in the ordinary
injection condenser, which will be made manifest by the following comparison,
videlicet, water for the condensation of steam is commonly obtained at a
temperature of about sixty degrees Fahrenheit, and it issues from the ordinary
condenser at about one hundred and ten degrees Fahrenheit. The increase of
temperature is (110-60) = 50° Fahrenheit. From my improved condenser
it issues at about two hundred degrees Fahrenheit, the increase of the tempe-
rature is therefore (200-60) = 140° Fahrenheit. It would appear from this
that I effect a saving of condensing water in the proportion of one hundred and
forty to fifty; but it is in reality still greater, because the condensed water
issues from my improved condenser at the temperature of two hundred degrcos
Fahrenheit, while in the ordinary condenser it is necessarily cooled down to
one hundred and ten degrees by an additional quantity of injection water at
sixty degrees Fahrenheit.
Second, a large quantity of nearly boiling hot water is obtained, which may
be used advantageously for feeding the steam boilers, for washing, dycing,
heating of buildings, and other useful purposes.
Third, it takes less power to work the piston of the small cylinder C, than
the air pump of an ordinary injection condenser B.

page_text: With regard to high-pressure, stationary, and locomotive engines, there are
some additional advantages obtained besides those already enumerated. They
are,-
Firstly, one atmosphere of effective pressure upon the working piston is
gained.
Secondly, the expansive cistern may be carried out advantageously to a much
greater extent than hitherto.
Thirdly, the condenser is very light, it occupies little space, and effects a
vacuum after the first stroke of the engine, without involving the necessity
of blowing steam through it previous to starting.
Fourthly, a large proportion of the waste steam of the engine escapes uncon-
densed into the atmosphere, and may be used for impelling the draught of the
chimney, or other purposes.
The second part of my Invention relates to my Regenerative Engine (sec
Specification of my Patent, dated Twenty-second December, One thousand
eight hundred and forty-seven), and consists of an improved valve for distri-
buting the steam or other fluid, on leaving the cylinder, over the regenerative
compartments, and for receiving the same back at proper intervals into the
same cylinder.
Sheet II., Figures 1, 2, 3, and 4, represent respectively an elevation, a plan,
a sectional elevation, and a sectional plan of the same. It consists of a cast-
iron casing A, which is cylindrical inside, but has externally the appearance of
a shortened cone. The inner cylindrical surface contains twelve (or other
number) of rectangular apertures which communicate, each separately, with
one regenerative compartment, through pipes (p, p,) leading into the outer
casing of the valve, with the exception of two, one of which, a, communicates
with the boiler, and the other, b, with the condenser of the engine. The
breadth of the apertures varies; the one nearest to a being the smallest, the
following one a little larger, and the one adjoining 6 the largest of all.
Between the apertures a and b are two, and between the others only one
groove, which contain each a strip of metal c. These strips fit steam-tight
between the sides of the grooves, and are pushed inward by means of springs d
and screws e against the periphery of a solid drum B, which is fastened upon
an upright shaft C. The periphery of the drum contains one rectangular
aperture, which leads through the passago f to the exhaust pipe g of the
cylinder; packing rings h, h, which are pushed outward by circular springs i, i,
form steam:-tight connections between the drum and the top and bottom
covering of the valve casing. The weight of the drum B and shaft C is
supported in a socket by the bracket D, and it is steadied at the top by a set

page_text: screw k. Upon the shaft C is keyed a conical wheel l, which is geared into
wo other conical wheels m and n, with double the number of teeth. The
atter are at liberty to revolve upon the horizontal shaft E, but partake occa-
sionally of its motion (which it receives from the engine, making two revolutions
for every one of the former) through the medium of clutch boxes o and p,
which are slided backward and forward alternately by means of a sliding
shaft %
with its arms r and s. The latter receives its motion from a cam t
on the wheel, which pushes against the stud u, and thereby changes the
motion of the valve after every one revolution. The side strain upon the
spindel C, which is occasioned by the unequal pressure in the different regene-
rative compartments) is resisted by adjustable bearings v, v. Through the
centre of the set screw k passes a slender spindle which partakes of the motion
of the valve, and carries a hand w at its upper extremity, which indicates the
exact position of the passage f, the relative position of the apertures in the valve
casing being marked upon the dial plate x. This valve works as follows:-
At the time when the steam or other fluid within the cylinder has nearly com-
pleted the stroke of the piston or moving trunk, the aperture in the periphery
of the moving drum, which previously covered the aperture a, begins to move
round, discharging the contents of the cylinder successively into the different
compartments, until it reaches the aperture b, where it suddenly stops until
after the return stroke of the engine is nearly completed, when it begins to
move in the opposite direction, receiving back steam from the different
compartments, until it again stops upon the aperture a.
Having now described these parts of my Invention, and the best mode I
am acquainted with for carrying the same into effect, I wish it to be under-
stood that I do not confine myself to any of the details herein described, as the
same may be varied without departing from the nature of the Invention. Nor
do I claim the discharging of steam, after it has served to propel the piston of a
working steam cylinder, into the atmosphere, previous to condensing the
remaining quantity, an arrangement to this effect having already been described
in my Patent, dated Twenty-second December, One thousand eight hundred
and forty-seven. But what I claim is,-
Firstly, the successive condensation of steam by means of metal surfaces, as
herein described, which enables me to obtain the condensing water at a very
elevated temperature.
Secondly, the partial discharge of the steam cylinder either into the open
atmosphere, or the chimney, or other apparatuses wherein it may be usefully
employed previous to and in connection with the successive condensation by
means of metal surfaces.

page_text: Thirdly, the double lip valve, as herein described, in connection with
condenser for locomotive engines.
Fourthly, the modes herein described for imparting motion to the con-
densers.
Fifthly, the mode of constructing valves for engines to be worked by steam
and other fluids, described in respect to Drawings Sheet II.
The third part of my Invention relates to the evaporation of brine or other
liquid, and consists in so constructing apparatus for that purpose that the
steam or other vapour, which is formed in consequence of the evaporation
of the said liquids, is caused either to accumulate, or to be compressed into
a smaller compass, whereby its temperature is increased, and it is made
available to support the further evaporation of the same liquid by its own
continued recondensation, in consequence whereof a large saving of fuel is
effected.
<
In order that this part of my Invention may be most fully understood and
readily carried into effect, I will now proceed to describe the best arrange-
ments I am acquainted with for effecting the same.
Sheet III. exhibits my improved apparatus, which I propose to term a
Regenerative Evaporator," in consequence of its analogy in principal to the
regenerative engine and condenser before described. Figure 1 shows a front
elevation of the same, with part in section; Figure 2, a plan, with a portion of
the covering removed; Figure 3, a section; and Figure 4, an end view of the
whole apparatus.
Its main body is composed of series of wrought iron
plate a, a, a, and a, a, a', which rest along their edges between wood
frames A, A1, A2, and B, B1, B2, and form therewith series of shallow
pans capable of holding water. The details of this apparatus will be best
understood in going through the history of its erection: The sleepers c, c, c
are laid at certain distances apart upon a level surface of ground. Upon
them are laid four longitudinal strips of timber d, d, d, d, of the intended
length of the apparatus, which are perforated with holes at certain distances
apart, corresponding with the breadth of the plates a, a, a, and a¹, a', a',
before mentioned, for the reception of bolts b, b, b. Next comes a light deal
flooring e, of the intended length and breadth of the apparatus, and that again
is covered with a sheet of zinc f, except at one end (towards the right), where
its place is occupied by a flat wrought-iron steam chamber C, which covers
between and part of the whole area. Upon the zinc plate f is placed an
outward frame of wood B, with cross partitions h, h, at intervals, corresponding
with the breadth of the plates a, a, a: Each of these partitions is perforated
with a considerable number of holes i, i, i (see Figures 1 and 3), which

page_text: incline upward from right to left. The upper surfaces of this frame (which is
on a level with the upper surface of the steam chamber C, are coated with
thick oil paint immediately before the plates a, a, a (which are about of an
inch thick), are laid on cach plate, covering exactly one partition of the frame.
The last plate, towards the right, rests with one side upon the steam chamber C,
and a cement joint is formed between the two. Next in order comes a second.
wood frame A, which in all its parts exactly covers the first, but is made about
three times deeper. The cross pieces k, k, of this frame, sce Figure 3, contain.
each one large rectangular orifice 1, and two small holes m, m, near the bottom.
surface; a piece n, of pottery ware or other non-combustable material, is let in;
at the middle of each partition, and serves to support the round or oblong iron.
flues p, p, p, which pass through the whole length of the apparatus. The
aperture does not occupy the same position throughout, but changes alter-.
nately from front to back in consecutive partitions, whereby a great zigzag.
passage is formed throughout the whole length of the apparatus, as indicated.
by arrows in Figure 2. The back of this frame is composed of short
pieces o, o, o, which are furnished cach of them with a longitudinal spy or man-.
hole, and wood pluck g. The front is left nearly entirely open, but is armed.
with doors r, r, r, opening upward, excepting the end compartment towards.
the left, the front opening whereof remains uncovered. These doors are made
of wood and lined with Mackintosh cloth, which also forms the hinge, but a
strip of vulcanized india-rubber cloth, about eight inches broad, and nailed
along the upper side of the openings, will answer equally well. In each parti-
tion between the sides k, l, is fitted one or more pieces of metal s, which I.
propose to term deflectors, for reasons hereafter explained. The frame is then
painted on its upper surfaces, and covered with light wrought-iron plates a¹,.
a', a', excepting the end towards the right, where a second steam chamber C¹,
is laid on instead. Upon the layer of plates a¹, a', a', is fitted another shallow
framing B', which is in every respect similar to the one first described; this
again is covered with plates a, a, a, whereupon follows another deeper.
framing A'; and the same repetition of shallow and deeper framings, with
steam chambers at the one end, may be repeated an indefinite number of
times. The uppermost deep framing A is covered with light plates throughout.
its whole length, and, in addition to that, with a layer of common deal.
board c', c', which is held down by four longitudinal strips d', d', d', d'. The
bolts b, b, b, pass through the several frames, plates, &c., and receive nuts and.
washers at their screwed projecting ends, whereby the whole apparatus is firmly
bound together. Lines of cast-iron troughs T, T', T2, are bolted against the front-
surface of the apparatus which are made to hold liquid, and form extensions

page_text: to the series of pans A, A', A². Along the back of the apparatus are laid
courses of pipes D, D', D³, each course consisting of four separate lengths
with branches u and v at the ends, which extend respectively into the frames
A, A, A, and B, B1, B2, as shewn in the Drawing. Through the whole
length of the deeper pans A, A1, A2, pass bars of wrought iron E, E, E,
which are joined together at one end, and are at liberty to slide backward and
forward. In each compartment is a short cross bar t, t, t, all of which are
fastened to the longitudinal bars E, E, E, by means of small brackets. At
the right-hand side of the apparatus is placed a boiler G, which has the
appearance of a flat covered pan with a curve in its bottom surface, which
enables it to yield to unequal expansion of the metal. It is provided with a
steam dome H, a safety valve I, a manhole K, and a furnace L. The steam
dome H is connected with the steam chambers C, C³, C³, by means of a steam
pipe w and its branches x, a³, a². A feed pipe y, which is provided with a
cock, connects the boiler with the upper range of troughs T. The fire channel
passes under one side of the boiler, the other side below the steam dome and
manhole being placed on solid brickwork, and terminates in the flues p, p,
which conduct the fire to the opposite end of the apparatus, where it issues
into the chimney M. The draft is regulated by dampers Z, Z, Z, at the
extreme ends of the flues p, p, p. These flues are cleaned in the usual
manner, and the brushes used for that purpose are put in through the door 1.
Close to the chimney is a fan N, the suction ports whereof communicate with
a chamber O, which in its turn is connected with the frames (B, B', B³,)
through the main passage P and its branches (2), (3), and (4). The blast
pipe (Q) of the fan extends into the chimney M, with the end slightly con-
tracted, and inclining upward. Previous to starting this apparatus the brine
or other liquid intended for evaporation is allowed to flow into the uppermost
range of pans (A2) through a pipe (5), which is provided with a cock (6).
The fluid will pass on freely from one compartment to the other through the
communicating holes (m, m,) in the partitions, and assume a level position
throughout; but after it has reached the heights as indicated by a green
tint in the Drawing, it will overflow through a short upright pipe (7), into
the second range of deeper pans (A'), and having filled that also up to a
certain level, it will flow into the third range (A) through a similar short
pipe (8), which again is provided with an overflow pipe (9) for the discharge
of an excess of fluid. By this means the evaporating fluid can be maintained
at an uniform level in all the pans. The boiler is charged only occasionally
with the same fluid through the feed pipe (y). The working of this apparatus
is as follows: The pans A, A', A³, and the boiler (9) being charged with

page_text: liquid, a fire is kindled and maintained in the furnace L. In the course of a
few hours a sufficient amount of steam will have been generated in the boiler
to heat the steam chambers and the liquid (brine) in contact therewith to
about 210° Fahrenheit, and the remaining portions of the apparatus will in
the meantime have been warmed to some extent by the fire in passing through
the flues (p,p,p). The fan N is then put in motion, and causes currents of
air to pass through all parts of the apparatus; but I may here observe that
each series of pans containing the brine or other liquid, together with one
range of shallow compartments and a steam chamber below, forms one com-
plete circuit or working element, which may be worked cither separately or in
connection with several repetitions of the same placed one upon another in the
manner herein described, for the purpose of economising space and material,
and of diminishing losses of heat from radiation. It will therefore suffice to
describe the working of only one of these repetitions. A current of air (induced
by the motion of the fan) enters the serios of pans A, through the front open-
ing near the chimney, and passes along the surface of the liquid through the
great zigzag passage, which is formed by the rectangular orifices (1, 1, 1,) in
the partitions. Arriving at the point where the first branch u enters the appa-
ratus, the current divides into two nearly equal portions, one of which enters
the branch u, and passes through the first section of the pipes D and its second
branch vinto the lower range of compartments B, which it traverses passing
through the perforated partitions h, and is finally propelled through the fan N
into the chimney. The remaining portion of the current proceeds in its zigzag
course until it reaches the second branch u, where it splits again into two
equal portions, one of which returns through the second pipe D, and the lower
range of compartments (which it enters close to where the first branch u leaves
the upper range) towards the fan, and the other proceeds until it reaches. the
third branch u, where it once more divides into a returning and a progressing
current. The latter passes over the heated liquid which covers the steam
chamber G, and on reaching the extreme end of the apparatus, it enters the
fourth and last section of the pipes D, which conducts it into the lower range
of compartments, where the steam chamber ends, bearing in mind the following
laws of nature, videlicit, firstly, gases penetrate each other; secondly, water, in
common with other liquids, continues to evaporate until its surrounding atmo
5 sphere is saturated with vapour, or is filled with vapour of its own temperature
and corresponding density; and thirdly, a given space has a certain capacity
for vapour varying with the temperature only; but it is of no importance
whether the said space is preoccupied with any other gases, or whether it was
perfectly empty. It will be readily understood that the current of air in

page_text: passing along the surface of the heated fluid over the steam chamber mixes witl
vapour arising therefrom until, if sufficient time is allowed, the vapour atmo
sphere has acquired such density as is due to the temperature of the liquid
itself. If that temperature is 192° Fahrenheit, the density or elastic force o
the vapour will be such as to balance a column of mercury of twenty inches
(according to Dalton); and the total pressure of air and vapour put together
being always equal to that of the external atmosphere, or thirty inches of
mercury, it follows, that the mixed current will be composed of 30-20=10
.volumes of air for every twenty volumns of vapour which it has absorbed.
The current thus constituted enters the lower range of compartments (B), and
in its progress towards. the fan the vapour which it contains gradually recon-
.denses in heating the cold brine (or other liquid) in the upper compartments
(A), which it does in such a manner that the temperature of the liquid close
to the stean chamber riscs nearly to an equality with that of the return
-current in its most heated state; but it gradually diminishes in proportion as
the condensation progresses, and at the extreme end of the apparatus the
liquid remains comparatively cool, the heating power of the returning current
.being nearly exhausted when it reaches the chimney. In course of time, how-
.ever, the liquid would become heated throughout, but for the cooling influence
.of the fresh current which enters the apparatus in a dry state, and will readily
absorb some vapour from fluid only moderately heated; but in proportion as
the vapour accumulates the current comes in contact with liquid of increased
temperature, which gives rise to additional evaporation, and in reaching the
.steam chamber, it contains only so. much less vapour than the returning
current in its most heated state as to leave the latter possessed of the neccs-
sary preponderance of temperature, which causes it to give off heat to the
former. I have here considered the working of that current only which
traverses the whole length of the apparatus, and which I propose to term the
"primary current." This by itself would constitute a very cconomical evapo-
rator, inasmuch as all the vapour which recondenses in the lower compartments
constitutes a positive saving of heat; but this saving is greatly augmented, and
at the same time a more uniform rate of evaporation throughout the whole
apparatus is established, by adding the third section and first section of the
pipe through which pass, what I propose to termi, the secondary, tertiary, and
quartary currents. The function of these currents I shall endeavour to explain
by the following remarks, in addition to the Diagram, Sheet III., Figure 5.
The different currents are represented in this Diagram by arrows of different
colours, and their number expresses the relative volumes of air which pass in
a given time (choosing the simplest proportion). The degrees of Fahrenheit

page_text: inscribed denote the supposed temperature of the currents at different points,
and the figures below them denote the volumes of vapour which the current
will contain at those temperatures for every ten volumes of air (these figures
are calculated from Doctor Dalton's Tables, which give the elasticity of vapour
at different temperatures). It will be observed that the return current con-
tains everywhere double the number of volumes of vapour for ten volumes of
air (supposing the two to be separated) than the upper current, and that the
corresponding differences of temperature, average twenty degrees Fahrenheit,
except at the first junction, where the difference amounts to only 12.25°, but
may also be varied to 20°, by diminishing the quantity of air in the primary
current, but which I here neglect, in order to avoid fractions. This prepon-
derance of temperature in the return current gives rise. to the constant trans-.
mission of heat from below to above. It is at the first junction represented
by an excess of 20-10-10 volumes of vapour in the lower current; but it
will be observed that at the second junction an excess of only five volumes
suffices. The remaining five volumes will therefore rather pass uselessly away,
or the capacity of the upper current for absorbing vapour must by some means
be doubled without increasing its temperature, and this I effect by joining the
secondary current to it which possesses the same absorbing power as the
primary. At the third junction, or, properly speaking, between the second.
and third, the requisite excess of temperature in the lower current is repre-
sented by only two and a half volumes of vapour; and the primary and
secondary current having again united, it follows that the quantity of air
passing the upper compartments at this point must again be doubled, and is.
therefore represented by four arrows. Between the third and fourth junction
a difference of 21-11-11 volume of vapour for every ten volumes of air
suffice to establish the difference of temperature of 20° Fahrenheit, and the.
previous difference being = 2 volumes, it follows that the upper current may
If the apparatus was
again be doubled, or be represented by eight arrows.
made longer a fifth or quintary current might be added; but here the volume.
of air would become so large, as compared to the additional liquid evaporated,
that the gain would become doubtful. The atmospheric air enters the appa-
ratus with its own temperature of about 60° Fahrenheit, and according to the
diagram it makes its exit at 117° Fahrenheit, but in reality it would be still
cooler, because a considerable quantity of heat goes to raise the temperature
of the evaporating liquid itself. The amount of vapour which each current
absorbs in a given time, and which is expressed by the number. of arrows
multiplied by the volumes of vapour, is equivalent with the amount supplied
by the steam chamber. The latter constitutes the consumption of heat, and

page_text: amounts only to one fifth part of the total evaporation. It is, however, neces
sary to observe, that I attach no absolute value to those Figures, but only use
them for the purpose of illustration. The relative strength of each current
can be easily adjusted in practice to the temperatures, by partially filling up
the passages (u, u,) with pieces of wood or iron, these passages being acces
sible through the manholes. In brine and other saline solutions a certain
affinity exists between its component parts which decreases their tendency to
evaporate. The current of air in passing over them is not saturated with
vapour; but the evaporation stops whenever its own power to absorb ceases
to outweigh the affinity in the liquid. In order to compensate for this affinity
I raise the temperature of the current slightly beyond that of the liquid itself,
and thereby increase its capacity for vapour. This I accomplish by causing
the fire to pass through the flues p, p, which in their turn cross the current in
every partition, and being hottest at the end toward the boiler, and becoming
cooler toward the chimney, they are well adapted for heating the current in
proportion to the local temperature of the liquid. The object of the curved
pieces of metal s,, s, is to deflect the current downward, so as to impinge upon
the surface of the liquid, whereby its evaporation is accelerated. The long
iron bar E, with its cross pieces t, t, receives a slow reciprocative motion
during the working of the apparatus, which causes the liquid to circulate
within every compartment, and prevents thereby the formation of a continuous
crust of salt on its surface. The crystals, moreover, always form and drop in
the least disturbed portion of the compartment, from whence they may be
raked into the troughs T, T, T, through the opened doors without difficulty.
They are afterward removed from the troughs and dried in the usual manner.
The size of the crystals can be regulated by the speed of the agitator, and by
the rapidity of the current itself. The condensed water which is continually
formed in the lower compartments B, follow the current into the pit o, from
whence it is conducted away through a pipe (12). The water which.con-
denses in the steam chamber is discharged into (B) through a small pipe (13),
which is provided with a regulating tap. The holes in the perforated parti-
tions incline upward, and direct the current against the plates (a, a, a₂)
which, in consequence thereof, absorb the heat more readily. The boiler (G)
which supplies the steam chambers is supplied occasionally with brine through
the pipe, on which occasions the safety valve I must be lifted from its seat, in
order that the fluid may flow in by its own gravity until it reaches the upper-
most test cock (14). The salt which will be formed within the boiler (and
which is of the finest description) accumulates on that side which is not
touched by the fire, and is occasionally raked out through the manhole K.

page_text: It will sometimes be more advantageous to use an ordinary steam boiler in
place of the one just described, and to feed the same with pure water in the
usual manner. The steam may be raised therein to a considerable pressure,
and its mechanical force be made use of for working a high-pressure engine
before it is taken to the steam chamber. The uses whereto the power thus
gained may be turned, will become manifest after I have described the following
part of my Invention.
Sheet IV. exhibits a different arrangement of my improved evaporator,
which may be worked either separately or in conjunction with the apparatus
just described. Figure 1 shews an elevation partly in section; Figure 2, a
plan with the covering plate in part removed; and Figure 3, a sectional end
view of the same. It consists of a number of steam chambers A, A, of the
whole length and breadth of the apparatus, which are placed between longi-
tudinal side frames B, B, and form steam-tight joints therewith. The upper
surface of the steam chambers is curved at the ends, and each curve is con-
tinued for some distance by a projecting plate e, as will be best seen from the
Drawing. The apparatus is enclosed above with a sheet of iron plates b, and
the whole is firmly combined by means of upright bolts c, c, c.
The projecting
ends of the steam chambers are inclosed with wrought-iron boxes D and E,
which are open toward the bottom, and dip into tanks F and G. From cach
steam chamber proceeds a branch p, which all unite into a main pipe P, and
are therethrough connected with the valve box of a pumping cylinder H. The
upper surface of the steam chamber forms, with the side frames B, B, shallow
pans containing the evaporating liquid, which is supplied through the pipe d,
and overflowing the least projecting end plate e of the highest pan, it falls into
the second, overflowing that into the third pan, and so on, until, after all the
pans are filled, the excess collects in the cisterns F and G. At either end of
the pans are placed shafts s, s, which pass through stuffing boxes into the
exterior of the apparatus, and carry at their ends conical wheels t, t, which
gear into other sets of wheels u, u, u, upon the two upright shafts T and T.
The latter receive their motion from a horizontal shaft S, which is provided
with a strap pulley V. Each of the shafts s carries two rope pulleys v, v',
over which pass endless ropes w, w. The two ropes are connected at
intervals to flat iron bars x, x, which they drag slowly along the bottom surface
of the pans, carrying with them the crystals of salt or other solid matters
which may have accumulated therein, and discharge them into the tanks F
and G, from whence they are removed by means of rakes, and disposed of in
the usual manner. The interior of the apparatus communicates with the
cylinder H, through the pipef and the slide valve
g. The apparatus works

page_text: as follows:-Steam is admitted into the steam chambers A, A, through a
small steam pipe 7, until the brine (or other liquid) contained in the pans is
heated to its boiling point. The piston p of the cylinder H, and the slide
valve g, are then put in motion whereby the steam which arises from the
heated liquid in the pans is forced into the steam chambers A, A, and being
therein compressed, its temperature increases to such an extent that reconden-
sation takes place, in consequence whereof an additional quantity of brine is
evaporated. By a continuation of this process the same portion of heat is
used an indefinite number of times to generate vapour from the evaporating
liquid, and only so much steam is continually supplied from a boiler through
the pipe has is necessary to compensate for losses of heat from radiation, &c.
The lever of a regulating cock i, in the steam pipe h, is connected with a
float k, which rises and falls with the level of the, fluid in the wrought-iron
funnel or box D, and administers the supply of steam in inversed proportion
to the density of the vapour atmosphere in the apparatus. The condensed
water and permanent gases escape from the steam chambers through pipes l, l,
The heat contained
and a main pipe m, which is provided with a cock n.
therein may be extracted by the fresh supply of evaporating liquid previous to
entering the pans. The amount of power which will be absorbed in working
the cylinder H depends upon the compression of the vapour necessary in order
to cause its recondensation. This again depends upon the boiling point of the
evaporating fluid, which, in case of brine, lays at 225° Fahrenheit (under
atmospheric pressure). In order to raise the condensing point of the vapor
to this temperature, it must be compressed to about five pounds per square
inch above the pressure of the atmosphere, and compressing it to seven or
eight pounds per square inch will give it sufficient preponderance of tenipe-
rature. The power is obtained from an engine which I prefer to work by
steam raised in the boiler of the first evaporator herein described previous to
its entering the steam chambers of that apparatus.
Having now described this third part of my Invention and the best means
I am acquainted with for effecting the same, I wish it to be understood that I
do not confine myself to any of the details herein described, as the same may
be varied extensively without departing from the nature of the Invention.
But what I claim are, the improvements herein described of evaporating
liquids.
In witness whereof, I, the said Charles William Siemens, have hereunto
set my hand and seal, this Twentieth day of September, in the year
So Loud One thousand eight hundred and forty-nine.
CHARLES WILLIAM (L.S.) SIEMENS,

page_text: AND BE IT REMEMBERED, that on the Twentieth day of September, in
the year of our Lord 1849, the aforesaid Charles William Siemens came
before our said Lady the Queen in Her Chancery, and acknowledged the
Specification aforesaid, and all and every thing therein contained and speci-
fied, in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Enrolled the Twentieth day of September, in the year of our Lord One