IMPROVEMENTS IN STEAM GENERATORS."
Year: 1857

page_text: LETTERS PATENT to William Smith, of No. 10, Salisbury Street,
Adelphi, Civil Engineer, for the Invention of "IMPROVEMENTS IN STEAM
GENERATORS." A communication from Jeau Marrie Prost, Officer in the
Imperial Navy
Sealed the 15th December 1857, and dated the 16th June 1857.
PROVISIONAL SPECIFICATION left by the said William Smith at the
Office of the Commissioners of Patents, with his Petition, on the
16th June 1857.
I, WILLIAM SMITH, of No. 10, Salisbury Street, Adelphi, Civil
Engineer, do hereby declare the nature of the said Invention for "IMPROVE
MENTS IN STEAM GENERATORS," a communication from Jean Marrie Prost, of
Paris, Officer in the Imperial Navy, to be as follows:-
In steam generators intended to produce superheated steam it is most
important to prevent the superheated steam from raising over or falling
below a previously fixed limit.
The object of this Invention is to combine a regulator that will restrain
the variations and maintain a normal degree of temperature. To attain
this purpose, it is necessary to ascertain the degree of temperature of
the steam at any moment, and to cause the feeding of water to vary
accordingly. The same amount of.feed water must always be produced

page_text: by the pump, and an overflow valve is called into action whenever the
temperature raises above or descends below the normal point, which
allows or prevents the whole of the water entering the boiler. Now
this Invention consists in applying to steam generators an improved
apparatus for ascertaining and regulating the temperature, and which
is recorded by a visible and audible signal when it is over or below the
normal point, and also in applying a new apparatus for condensing the
escape steam and for the reheating of the feed water.
Fig. 1 of the annexed sketch is a thermometer or contrivance to
show the degree of heat of the superheated steam emerging from the
boiler. ,, r, r, steam chest; a, b, spiral coiled tube, fitted in the
chest containing the liquid. The tube a, b, is connected with a metallic
steam guage, on the dial of which a hand f works. The axis of the hand
carries a sigment c, d, which holds a small pin i, fixed on the ring of a
spur wheel R, which calls suitable clockwork into action as soon as the
segment escapes the pin i, and so gives the alarm.
Fig. 2 is another similar apparatus, in which a tube a, a', a", a", fitted
in a steam chest is filled with mercury, and in which a piston p in the
cylindrical branch a", a", plays up or down, according to the dilatation
or contraction of the mercury; the rod of the piston is connected with
a set of levers and actuates the hand A, B, y, which hand shews the
degrees of heat on a graduated segment A, A. The hand may be con-
nected with a moveable segment o, s, t, which holds a pin i which
projects from the rim of a spur wheel R, as in Fig. 1. The same hand
d, B, y, in its to-and-fro motion, actuates a small carriage Q, the wheels
of which run over a double-branched lever l, m, n, which lever bears
on an overflow valve S, which closes an aperture in the feed pipe T',
and this valve raises more or less, according to the position of the
carriage Q, allowing more, or less of the feed water to escape.
The same effect might be produced by other similar contrivances.
An electric fluid is also applied in the manner represented Fig. 3, in
which an electro-galvanic battery is in connection with the thermome-
trical apparatus first described for regulating the temperature. The
hand of the steam guage is divided into two parts by small ivory or
any other nonconducting knob v. The negative pole of the battery is
in permanent communication at with the hand f; small pieces of
silver m, n, are fixed on each side of the hand, and two other similar
pieces d, e, are fixed at the end of the weak springs c, d, h, e, in per-
manent contact with the positive pole of the same battery, so that when
the heat increases or decreases in the steam chest r, 7, 7, 7, the hand f
moving either way, the peices of silver will come into contact, and the
circuit will be closed, and then a system of electro-magnets E, E", suit-

page_text: ably disposed on a swing lever a, B, y, will impell a carriage Q running
on a lever L, W, W, which allows the overflow valve S of the feed
pipe T" to open more or less, as before stated.
In superheated steam generators, pure distilled water being required,
the steam must be condensed after working, so as to be again generated!
Fig. 4 is a condensing apparatus used for this purpose; it is composed
of two steam-tight chambers C, D, in communication with one another
by means of small tubes a, a, a; these combined steam chambers are
fitted in a rectangular tank M, N, O, P, opened at the top and filled with
water, which flows in from the bottom through the pipe R, R, and
raising up to b, b. The escape steam flows through the pipe T into the
chamber C, and thence through the small tubes a, a, a, into the
chamber D, being partly condensed in its passage by the surrounding
water T. a-tube leading the condensed water to the air pump. The same
apparatus, slightly modified, can be used for heating the feed water,
the steam after working the piston being conveyed in the chamber C,.
and after flowing through the tube a, a, a, will escape in the atmo-
sphere through the pipe T; the feed water arriving through R, R, will
be supplied to the feed pump from the top of tank M, N, O, P.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed,
by the said William Smith in the Great Seal Patent Office on the.
15th December 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SMITH, of No. 10, Salisbury Street, Adelphi, Civil Engineer, send..
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of June, in the year of our Lord
One thousand eight hundred and fifty-seven, in the
year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Smith, Her special licence, that I, the said William
Smith, my executors, administrators, and assigns, or such others as I,
the said William Smith,
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 law-
fully 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 STEAM GENERATORS," a communication from Jean
Marie Prost, Officer in the Imperial Navy, upon the condition (amongst
others) that I, William Smith, by an instrument in writing under my,"

page_text: or their, or one of their hand and seal, should particularly describe and
ascertain the nature of the said Invention, 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 William Smith do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement and accompanying Drawing.
. Generators of this description are composed of a series of tubes,
through which the water passes, and in its passage through them
becomes .converted into vapour. The feeding should be regulated in
such a manner that the water, during its passage through the steam
generating tubes and before reaching the escape orifice, should be con-
verted into vapour.
A regulator of temperature should be one which will decrease as
little as possible the variations on both sides of the middle temperature;
this temperature should be nearly constant, whilst the pressure varying
but little, the amount of, water vaporized in a fixed time should be pro-
portionate to the quantity of heat absorbed by the generator. The
feeding consequently should vary in proportion to the absorption of heat
by the generator, and for which reason the feed pump must always
supply more than the generator can vaporize in ordinary conditions.
The overplus of water supplied by the feed pump at every stroke of the
piston should escape from the feed pipe and flow back to the cistern;
this object can be attained in various ways. First, an overflow valve,
suitably loaded, is fitted in the feed pipe, which rises each time the
water is forced by the feed pump into the generator, allowing the over-
plus to flow back to the cistern. Another arrangement may be adopted
for effecting the same purpose, viz., the feed pipe may be made to com-
municate with the cistern by another pipe, provided with a flap valve
at its inlet. The water in passing through the pipe shuts, more or less,
the inlet valve, which allows a proportionate quantity of water to run
back to the cistern. The quantity of feed water entering a generator
in a limited time is proportionate to the excess of pressure in the feed
pipe over the steam chamber or chest, therefore the difference of these.
pressures must vary in order to get a variable feeding. Two ways can
be adopted to attain this, which is either by exerting a direct action over
the pressure in the steam pipe, or over the pressure in the steam chest.
It must be understood that the temperature would be constant, as also
the feeding, if the production of heat in the fire grate were always the
sante. The degree of heat can be brought to its normal state, should

page_text: it depart from it, by any of the usual means. The several thermome-
trical apparatus represented in the annexed Drawing will correctly
indicate at any moment the temperature of the steam.
DESCRIPTION OF DRAWING.
The apparatus Fig. 1 is composed of a partly spiral tube a, b, placed
within the steam chest r, r, to show the degree of heat of the steam
issuing from the boiler through the pipe T. The tube a, b, is filled with
a liquid up to 6, and the air exhausted from the tube. This precaution
is unnecessary if the temperatures intended to be measured are higher
than that of the boiling point of the liquid which evolve vapour, the
pressure of which varys with the temperature, which is constantly
indicated by the handle or pointer f of a metallic guage which is in com-
munication with the tube a, b. For graduating this thermometer the
tube a, b, is immersed in a bath the temperature of which is caused.
to vary by degrees by the side of a standard thermometer; when the
handle is stopped the division corresponding to it is marked on the
corresponding scale, the temperature of the bath is then raised again
and another division is marked; the intermediate divisions are got by
interpolation. When the. thermometer is graduated, a hole is bored
through the side of the steam chest r, r, &c., and the tube a, b, con-
taining the liquid is introduced in it so as to come opposite to the ingress
aperture T of the steam. The tube a, b, is held fast by a flange bolted
on the top of the steam chest. For the purpose of warning the fireman
when the heat is too high, a common alarum apparatus may be placed
near the thermometer. A wheel R carries a peg r, and projecting
therefrom upon the shaft O of the steam guage is a segment c, d, placed
behind and arranged in such a manner that when the temperature is
at its medium pitch it is opposite to and bears upon the peg i, and so
prevents the alarum from ringing; when the temperature increases, the
hand moves in the direction of the arrow, carrying round the segment
c, d, which being released from the peg i, allows the wheel R to revolve
and calls into action the alarum. The segment c, d, can be fixed by a
set screw at any required position on the shaft O, so as to permit of the
alarum ringing to any extent required. If the temperature decreases,"
the hand moves in the opposite direction, which also calls the alarum
into action, so that upon the fireman looking at the index hand he will
see at once what he is to do. If any other form of guage be used in
preference to the metallic guage, the indications would be the same.
The tube a, b, in the steam chest r, r, could be used for containing gas
instead of a liquid, which would expand when the temperature
increased, causing the hand f to move, and bringing the alarum into

page_text: action in the manner just described. The tube a, b, might even be
dispensed with, the steam guage merely being in direct communication
with the steam chamber r, r, the segment c, d, performing the same
duty by acting upon the alarum and shewing whether the steam is above
or below the medium point.
Fig. 2.shews a thermometrical apparatus of another description.
1, 7, 7, 7, is the steam chamber tube filled with mercury, secured at a'
& a' on the top and bottom of the chamber r, r, through which it passes.
The vertical part a", a", of the tube is cylindrical, a small piston p
moves freely up and down in the tube a", a", and resting always on the
mercury. Three metallic rods are jointed together at e, and hinged at
their opposite end, the first one at d upon the piston p, the second one
at the steady point f, the third one at g, with an indicator or hand g, h, y,
moveable at h. The rods d, e, and f, e, form together a very obtuse
angle; the rod e, g, divides the angle nearly into equal parts, that is
to say, that upon any vertical motion of the point d or piston p, there
will be a considerable amount of motion of the points d and g. When
the steam enters the chamber 7, 7, the coiled part 6 of the tube con-
taining the mercury is heated to the same degree, if then its temperature
increases, the mercury will expand and cause the piston p to rise and
the end y of the hand to move in the direction of the arrow; if the
temperature decreases the motion would take place in the opposite
direction, the bulk of the mercury contained in the tube remaining
constantly the same for the same degree of temperature; the lever or
hand g, h,.y, will assume the same corresponding position, and a
scale A, A, being suitably divided and disposed the several positions
of the hand y will shew on the scale the corresponding degrees of
temperature of the steam within the chamber ; r, that scale being
graduated by comparing the positions of the hand with the degrees of a
standard thermometer previously placed in the chamber r, r. In order
to prevent the mercury escaping around the piston p, the piston p may
be a hollow cylinder, through the top of which a small tube h', h', is
introduced, for the purpose of forcing a liquid at a high pressure within
the piston; if notwithstanding the mercury should still escape and the
indications of the scale A, A, should be incorrect, the piston rod could
be so arranged as to bring them right; the rod could be made in two
parts, having a right and left screw thread thereupon and a nut V, for
lengthening or shortening the rod. An alarm clock may be connected
to this thermometrical apparatus, as in the first one described. .R is
the first wheel of the clockwork arrangement, with a projecting peg i
resting on a segment s, t, which segment works on a centre o, and is
connected with the lever g, h, y, by the rod y, u. The segment s, t,

page_text: i,
following the motions of the hand h, y, when the temperature is either
higher or lower than the middle point, will release either way the peg
which being free to run by means of the clockwork, will call the bell or
alarum into action. The connecting rod y, u, can be formed of two.
parts, united by a screw nut for the purpose of shortening or lengthen-
ing it. This thermometrical apparatus can be made self-regulating, T"
being the feed pipe, and S the overflow valve; Q is a carriage, with 2
or 4 rollers or small wheels resting upon a horizontal lever l, m, n,
moveable at n, where they can run when the carriage is impelled by the
lever g h, y, in either direction. The lever l, m, n, bears at m upon
the valve S; when the piston p raises by the increasing temperature it
causes the carriage Q to depart further from the valve S, thus bearing
heavier upon
it and causing more feed water to be forced into the boiler,
which counterbalances the increase of temperature. If the piston p
falls the reverse action takes place. Instead of the carriage Q the
lever g, h, y, could be made to impell any other similar contrivance
for producing the same effect. When the mercury expands by the
increasing heat it will force up the piston p unless there was an
opening for it to escape, but when its bulk lessens by the decrease of
temperature the piston could not lower so easily, there being no pressure
to assist it, in which case it should be loaded with a weight.
The
arrangement I have adopted for that purpose is shewn in Fig. 2. - A
counterpoise P is fastened to the end of a rope which passes over a
pulley K, the other end of the rope being fastend at e will pull back the
lever f, e, which lever forces down the rod d, e, and with it the piston p.
Fig. 3 represents another arrangement or apparatus intended for the
same purpose. A long metallic rod a, b, c, is fastened at a in a stout
flange piece M in the steam chamber r, r, r, r, and forming part
thereof. The rod passes out of the chamber through a stuffing box P.
The rod a, b, c, is heated by the steam to the same degree, and expands
or shrinks as the temperature of the steam increases or decreases; the
variations in the length of the rod a, b, c, being ascertained at any
movement would shew the variations in the temperature of the steam.
To obtain more sensative indications from the same rod, the end b
of it is connected by a rod or link b, c, to the lever v, c, y, hinged at v.
If the ratio between v, c, and c, y, is, for instance, 1 to 30, the distance
travelled by the end y will be 30 times longer than the lengthening or
shortening of the rod, and what could not have been perceived at b will
be very apparent on the scale C, C. For the purpose of preventing any
motion at the point va rod v, x, is secured at one end to the flange M,
the opposite end being attached to the point of the rod v, y. The
degrees of the scale C, C, could be divided by calculation for shewing

page_text: the motion of the hand y produced by the changes of temperature
within the steam chamber 1, r; but it is better to graduate the scale by
comparing it with a standard thermometer inserted in the steam
chamber. An invariable thermometer might be used for comparing and
graduating the scale. It will be advisable to have the connecting rod
b, c, made in two parts, adjustable with a right and left threaded nut.
A signal or alarum apparatus similar to those described for Figs. 1
and 2 could be adopted for the same purpose by connecting the hand y
with a segment, as shewn in the Figures just described. The same
thermometrical apparatus could also be connected with a carriage
similar to Q, Fig. 2. This last-mentioned thermometer with the two
steady flanges or blocks M, M', is not only applicable to superheated
steam engines, but in numerous circumstances it could be applied as a
pyrometer where the common thermometers are inefficacious; it is
Brongniar's pyrometer improved by the addition of the blocks M, M',
and rod or hand c, y. It should be remarked that if the rod a,, b, and
steam chamber sides were made of the same metal they would expand
equally, therefore the rod a, b, would not move in its stuffing box, the
portion a, P, of the rod would be taken out from the chambers as well
as the stuffing box, and it would be firmly attached outside of the
chamber, which could be surrounded with a wrapper, not touching it,
to prevent the heat escaping, and the rod v, x, could be maintained at
a permanent degree of heat by being surrounded with water along its
entire length.
The apparatus shewn in Fig. 4 is intended for the same purpose, and
is composed of two metallic blades A, B, and C, D, of a different kind,
for instance, iron and copper, the expansibility of which is not the same;
they are of the same length, at a certain degree of heat, and put parallel,
being secured together by cross pieces t, t, t, of a very accurate length,
so that none of the blades can give way without carrying with it the
other one.
If the temperature raises above the normal pitch, the
blades A, B, expanding more than the blade C, D, the whole concern
will give to the side C, D, and each blade will assume the shape of an
arc of a circle. If the temperature becomes lower than the normal
pitch the blades would give in the opposite direction. If the two
metallic blades are firmly fitted at the ends A and C into the bottom or
side of the steam chamber r, r, r, r, the ends B and D will move either
one way or the other, according to the increase or decrease of the steam's
heat. In order to make this motion appear outside of the steam chamber
there is a straight piece E, F, which moves upon a center E; this
straight piece is slotted at f, f, through which a peg I fixed at the end
B, D, of the blades passes. The axle E passes through a stuffing box,

page_text: and carries a long rod K, K, parallel to E, E; and the end K moves
forward on a graduated scale S, S, suitably shaped. When the end
B, D, of the thermometer moves, it carrys along the end F of the straight
piece E, F, which works on the axle E impelling the rod K, K'. The
scale S, S, can be graduated by the help of a standard thermometer
plunging into the steam; and by causing the temperature to vary, the
various positions of the end K', corresponding to the degrees registered
on the standard thermometer, will be marked on the scale S, S. The
rod K, K', can (as in the lever g, h, y, of Fig. 2) call into action an
alarm clock, and also a carriage for actuating the overflow valve of the
feed pipe.
The several thermometers just described can be used to make useful
dynamic electricity to regulate the temperature of superheated steam,
or to call into action an advertising signal for the fireman, or to get a
self-acting regulation by the engine's own work. If, for instance, we
take the thermometrical apparatus shewn in Fig. 1 for this application,
which is illustrated at Fig. 5, a, b, spiral tube containing a liquid, which
is heated by the steam ingressing from the tube T into the chamber
7, 7, 7, 7. The hand, f, registers on a graduated dial the pressure
of the ingressing steam, and the degree of heat of the liquid contained
in the tube a, b. The hand f, f, is formed of two separate parts, united
together by a piece of ivory U or any other non-conductor of electricity.
The upper end of the hand bears two small silver bits m, n; two very
plyable springs c, d, and h, e, secured at c and h, each of which have a
small silver bit d and e corresponding to the first ones m, n. The hand
f, f, is in communication with the negative pole of a battery, through
a metallic wire insulated with silk or cotton thread; this wire is fastened
at K to the hand. The springs c, d, and c, h, are both in communica-
tion with the positive pole of the battery through the wires c, b, a, and
h, b, a, being united together at b. If the temperature is raising by
degrees above the medium, the hand moving in the direction of the
arrow, the silver bit n will come in contact with the bit e; then, the
circuit being closed, the fluid will run according to the direction
a, b, h, e, n, k, l. If then, between the point and negative pole, or
between the point b and positive pole of the battery an alarm clock has
been disposed, it will be caused to ring. If the temperature of the
steam becomes lower, the reverse effect takes place; the silver bits m
and d come into contact, and the alarm bell would ring again.. By
looking at the hand f, f, the fireman will be enabled to know whether
the temperature is too high or too low. Betwixt the points h, b, and
c. b. could be placed two bells of different sounds, for ascertaining what
is the state of the temperature. If it is desired to have the engine to

page_text: regulate its own temperature, the contrivance represented in Fig. 2,
with the overflow feeding valve and a moveable weight, could be
adopted.
In Fig. 5, T" is the feed pipe; S', overflow valve, which is pressed upon
its seat by the lever L, M, N; it is formed of two parallel rods, as in
Fig. 2, upon which the carriage Q runs; upon the axletree of the carriage
two rods v, a, are attached, they are parallel to the lever L, M, N.. The.
rods v, x (one only of which can be seen in the Figure) are cut, with
ratchet teeth, as shewn at d", d", being cut in the reverse direction
upon the other rod. A lever L, B, Y, working on a centre at B, bears
a cross-piece x, x1, on which two electro-magnets E, E', are fixed, corre-
sponding to each of the rods v, v. To each of the electro-magnets is a
keeper L', y, B', which works on a centre y, having a pawl. p,. L, work-
ing on the centre L', and has a hook or catch p for impelling the rod
v, a, by being brought into contact with the teeth d', d", &c. The
electro-magnet E' is provided with a similar keeper, but placed in a
reverse direction, for impelling the second rod v', a', placed behind the
one shewn in the Figure. A wire h, p, connects the spring h, e, with
the electro-magnet E; it is coiled around it, and passes from g, s, t,
to the positive pole of the battery. A similar wire c, p", passes from
the spring c, d, to the electro-magnet E', and coils around it, and runs
through g', s, t, to the positive pole of the battery, the hand f, f, being
always connected with the negative pole, as above stated. When the
temperature is increasing the two silver bits n and e come into contact
with each other, which closes the circuit through the electro-magnet E,
and attracts the keeper L', y, B', which brings the hook p into gear
with the tooth d', and the lever L, B, Y, oscillating in the direction
of the arrow impels the rod v, x, and carriage Q, the same action taking
place successively as long as the circuit is closed; and the load upon the
valve S increasing by degrees will cause the feeding to increase,
whereby the temperature will be lowered. When the silver bits n and e
are out of contact the keeper L, Y, B, is released from the poles of the
magnet, and brings the catcher p out of contact with the teeth d', d".
This action is produced by a spring y', z, fixed on the cross-piece t', t',
as also by the weight of the keeper, which tends to keep the latter in a
perpendicular direction to the lever L, B, Y. When the temperature
decreases the reverse effect will take place, causing the carriage to run
backwards. To allow of the catch p being released from the teeth, the
róds », a, are made to bear upon a roller M by means of a spring F,
having a rounded catch w also preventing the rods from receding back-
wards. The lever L, B, y, for impelling the carriage Q may be worked
by the engine by any suitable arrangement. The same result may be

page_text: obtained with a thermometer containing a liquid, such as mercury,
which is a good conductor of the electric fluid, a communication being
made through a wire from the liquid to the battery, and a second wire
being arranged in such a manner that when the mercury rises it comes
into contact with the second wire and completes the circuit. If the
liquid in the tube be a bad conductor it may have a metallic float for
completing the circuit. A pipe A', A", Fig. 5, connects the steam
chamber with the condenser; when the pressure is too high the safety
valve S rises, and the steam escapes to the condenser, answering the
purpose of a donkey engine for feeding the generator, and also for pre-
venting the tubes from being burnt by keeping them covered with
water. Steam generators, of the description herein mentioned, for pro-
ducing superheated steam, will vaporise only distilled water, it is there-
fore necessary to condense the steam after it has been exhausted, and
then again convert it into vapour. By the present mode of vaporising
it requires a great quantity of water, which, as for instance in locomotive
engines, it is not possible to have. To obviate this it is proposed to make
use of condensing apparatus, shewn at' Fig. 6, which is composed, 1st,
of two chambers C and D, communicating with each other by small
parallel tubes a, a, a; 2nd, a prismatic casing M, N, O, P, opening
upwards, with the tubular apparatus resting on its bottom. This outer
chamber or casing contains water up to b, b, covering entirely the tubes
a, a. The water passes through a pipe R, R', to the under part of the
casing, so as to preserve a constant, level. The steam, after being
exhausted from the steam.cylinder, is conveyed through the pipe T into
the chamber C, whence it passes through the small tubes. The con-
densed water mixed with air passes through the pipe T", which conveys it
to the air pump. The tubes a, a, should be inclined downwards from C
to D. When the steam issuing through the pipe T spreads within the
tubes a, a, their inward surface is in contact with superheated steam,
whilst their outer surface is surrounded with water of about 212 degrees
Fahrenheit, becoming heated by the tubes; steam passing through them
heats the surrounding water to about 212 degrees, the overplus heat
vaporising the water, the steam thus produced escaping into the atmo-
sphere, a proportionate quantity of the steam within the tubes being
condensed. If the tube surface is suitably proportioned to the quantity
of steam to be condensed, the difference of the outside and inside
temperature should not be above 45 or 48 degrees, and the pressure of
the steam within the condenser about 1 atmosphere, which pressure is
a little higher than if the steam was passing directly in the atmosphere.
The same apparatus, slightly modified, can also be used for heating the
feed water as much above as below 212 degrees in the common high-

page_text: pressure engines without condensation.
For this purpose the steam
issuing through the pipe T flows through the tubes a, a, and escapes into
the atmosphere through the pipe T'; the inside of the tubes will bring
it to a temperature of about 212 degrees, and the heat escaping outwards
through the metal will raise the heat of the water contained within the
outer casing M, N, O, P, about 36 to 38 degrees. The heat absorbed by
the water in the condensating chamber is derived directly from the steam
cylinder, and an amount of steam condensed proportionate to the heat
given off. If, for instance, the water is heated up to 176 degrees before
being forced into the boiler, which is about the of the quantity of heat
required to convert it into vapour, the quantity of condensed steam will
be of the steam passing from the cylinder, and the surface of the
tubes a, a, can be lessened to of what it should be for the complete
condensation; but the diameter of the said tubes must be larger in order
to slacken the admission of the steam. This process is the equivalent
of condensing a small fraction of the steam escaping from the cylinders;
the water entering always at the lower part of the outer chamber or
casing M, N, O, P, rises to the top to be conveyed to the boiler, whilst
the condensed steam passes through the pipe T'.
Having described this Invention, as communicated to me, I claim the
improvements herein described and relating to steam generators:
In witness whereof, I, the said William Smith, have hereunto set
my hand and seal, this Fourteenth day of December, in the year
of our Lord One thousand eight hundred and fifty-seven.
WILLIAM SMITH, C.E. (L.S.)
Witness,
GEORCE CHURCHILL.