IMPROVEMENTS IN STEAM GENERATORS, AND IN THE MEANS OF OR APPARATUS FOR SUPERHEATING STEAM, AND IN HEATING THE FEED WATER
Year: 1860

page_text: LETTERS PATENT to Abraham Pullan, of Fortie Cottage, New Cross, in
the County of Kent, Engineer, Thomas Cresswell, of Ravensbourne
Terrace, Lewisham, in the same County, Engineer, and Richard
Longstaff, of Mornington Road, New Cross, in the same County, Pattern
Maker, for the Invention of "IMPROVEMENTS IN STEAM GENERATORS, AND
IN THE MEANS OF OR APPARATUS FOR SUPERHEATING STEAM, AND IN HEATING
THE FEED WATER,"
Sealed the 6th November 1860, and dated the 12th May 1860.
PROVISIONAL SPECIFICATION left by the said Abraham Pullan, Thomas
Cresswell, and Richard Longstaff at the Office of the Commissioners
of Patents, with their Petition, on the 12th May 1860.
We, ABRAHAM PULLAN, of Fortie Cottage, New Cross, in the County of
Kent, Engineer, THOMAS CRESSWELL, of Ravensbourne Terrace, Lewisham, in
the same County, Engineer, and RICHARD LONGSTAFF, of Mornington Road,
New Cross, in the same County, Pattern Maker, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN STEAM GENERATORS, AND IN
THE MEANS OF OR APPARATUS FOR SUPERHEATING STEAM, AND IN HEATING THE FEED
WATER," to be as follows:-
Our Invention of "Improvements in Steam Generators, and in the Means
of Superheating Steam, and in Heating the Feed Water," relates, in the first
place, to various novel modes of constructing and arranging the parts of steam
boilers or generators for the purpose of increasing the heating surface, and of
causing the water to circulate through the boiler; and, secondly, to a novel
meuns or arrangement of apparatus for drying or superheating steam.
Pine 71

page_text: In constructing locomotive boilers we form a water space all round the
bottom of the fire-box, and connect this water space with the barrel or body
of the boiler by means of pipes, channels, or water spaces, constructed of
any convenient shape, so as to obtain a circulation of the water from the
barrel or body of the boiler down to the bottom of the fire-box.
By constructing boilers in this manner all 'sediment 'will be carried down
into the coldest part of the boiler, where it can be easily cleaned out, and
therefore the liability of the boilers to foul or become coated is considerably
diminished. We also construct locomotive boilers with a chamber underneath
the barrel or body, so as to receive all sediment from the said barrel or
body, and this chamber box is connected with the water space under the
fire-box by means of tubes, channels, or spaces, as before described.
For insuring dry steam in boilers of this description we employ the second
part of our Invention, which relates to a novel means of superheating steam,
for which purpose we arrange in the smoke-box a chamber or receiver(which
is connected to the boiler so as to allow the steam to pass into it), and in con-
nection with this chamber there are a series of small pipes or tubeswhich-pass
through the flue tubes of the boilers, and terminate in a long chamber placed
in the fire-box over the top of the fire. From this chamber another series of
tubes convey the steam into another chamber placed in the smoke-box, and
from thence the dry steam will pass into the cylinders of the engine. In order
to prevent the chamber at the fire-box end from being burnt, we arrange a
water space all around it, and connect this envelope with the water space in
the boiler. The steam pipes in the flues are connected with 'the boiler by
means of a cock,so that water may be admitted into these tubes while getting
.up steam, or while the 'engine is stationary for
any length of time. By this
means the superheating pipes are made part and parcel of the boiler. A cock
or valve is also adapted at some convenient place between the boiler and the
superheating tubes in order to shut off all communication with the boiler in
case of accident to the superheating apparatus; and we' sometimes carry
these tubes in the shape of a coil or otherwise over the top of the fire. When
the superheating apparatus is not required, or while getting up steam, the
feed water for the boiler is passed through the superheating tubes, and
thereby becomes heated before entering the body of the boiler, but when
the superheating apparatus is required the communication between this and
the feed water must be cut off, and nothing but steam allowed to enter the
tubes. We also propose to employ additional feed water tubes, which will
come in' use when' the superheating tubes are required for drying the steam.
In constructing vertical boilers for marine or stationary purposes, or for

page_text: portable engines, we construct an additional water space at the upper part of
the fire-box, and connect the same with another water space which extends
from side to side of the fire-box and over the top of the fire, and forms a kind
of ring. Our object in this arrangement is to obtain a large amount of surface
within a small space, and a perfect circulation of water throughout the boiler.
We alse arrange a water space under the fire-box, as before described in
reference to the locomotive boiler, and outside the vertical boilers we place a
wrought or cast-iron shell lined with fire-bricks, so as to form a flue whereby
the heat may be carried round-the outside of the boiler as well as in the fire-
box. In order to dry or superheat the steam, steam pipes are arranged in
coils round this flue.
In another form of vertical boiler we construct an additional fire-box or
chamber, which is placed horizontally, and is connected on each side with the
water spaces so as as to obtain a circulation of water throughout the boiler. It
will sometimes be found convenient. to pass tubes or chambers through this
additional fire-box or chamber in order to obtain a large amount of heating
surface within a small space. This boiler is also constructed with a water space
under the bottom of the fire-bars so that all the sediment may settle at the
coolest part of the boiler. We also construct vertical boilers with an additional
barrel from side to side of the fire-box over the top of the fire, and fitted with
tubes passing horizontally through. it, and fastened to the outer shell of the
boiler; a smoke box is placed opposite to the ends of the tubes of each boiler
for the purpose of causing the whole of the heat and gases to pass through them
before going into the chimney.. In order to connect the smoke-box with the
fire-box, we place tubes through the water space of the boiler; the smoke-box
may also be made with a water space all round it, to boil the salt water or to
heat the feed water, so as to supply the boiler with distilled water when used
for marine purposes without the aid of an auxiliary boiler, and to make up
the losses from leakages, coudensation, and other causes. We also make an
outer casing with a water space to surround locomotive boilers or tubular
boilers, and pass tubes through the water space of the boiler so as to cause the
heat and gases to pass round the outer casing of the boiler, for the purpose of
heating the water in the water casing.
"J
11
"1
In constructing high-pressure marine,locomotive, and stationary boilers, we
construct on the top of the boiler a long tube or chamber for the steam to rise
into from the boiler, and in order to heat the steam in this chamber the whole
or a portion of the heat from the fire may be passed through a series of tubes
arranged inside the chamber on the to; of the boiler. This chamber is con-
pected at one end of the smoke/box end of the boiler, and at the other end it

page_text: is fitted with a smoke-box communicating with a chimney or uptake from the
top of the furnace. The two smoke-boxes in the boiler are also fitted with
dampers so as to regulate the heat and the temperature of the superheated
steam, as is found desirable in practice.
In the ordinary form of marine boiler we propose to pass our tubes through
the tubes of the boiler for the purpose of superheating the steam, as described
in our other forms of boilers. We also arrange a chamber or vessel of any
shape inside the boiler; in this chamber we form two compartments,one end
of which is connected with the top of the combustion chamber or fire-box,and
the other end is connected with the uptake or chimney of the boilers,the outer
one being for the heat and gases to pass through into the uptake, and the
inner one being for steam space, which steam is thereby surrounded with
heated gases, and therefore becomes highly superheated.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Abraham Pullan, Thomas Cresswell, and Richard Longstaff
in the Great Seal Patent Office on the 12th November 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ABRAHAM
PULLAN, of Fortie Cottage, New Cross, in the County of Kent, Engineer,
THOMAS CRESSWELL, of Ravensbourne Terrace, Lewisham, in the same County,
Engineer, and RICHARD LONGSTAFF, of Mornington Road,in the same County,
Pattern Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of May, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said Abraham Pullan, Thomas Cresswell, and Richard Longstaff, Her
special license that we, the said Abraham Pullan, Thomas Cresswell,and Richard
Lougstaff, our executors, administrators, and assigns, or such others as we,
the said Abraham Pullan, Thomas Cresswell, and Richard Longstaff, our
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 the Isle of Man, an Invention for "IMPROVEMENTS IN STRAM
GENERATORS, AND IN THE MEANS OF SUPERHEATING STEAM, AND IN HEATING THE
FEED WATER," upon the condition (amongst others) that we, the said Abraham

page_text: Pullan, Thomas Cresswell, and Richard Longstaff, by an instrument in
writing under our hands and seals, or under the hand and seal of one of
us, 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 1, the said Thomas Cresswell, on behalf of myself
and of the said Abraham Pullan and Richard Longstaff, do hereby declare
the nature of our said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, and to
the letters and figures marked thereon (that is to say): -
-
Our Inventicu of "Improvements in Steam Generators, and in the Means
of Superheating Steam, and in Heating the Feed Water," relates, in the first
place, to various novel modes of constructing and arranging the parts of
steam boilers or generators for the purpose of increasing the heating surface,
and of causing the water to circulate through the boiler; and, secondly, to
a novel meaus or arrangement of apparatus for drying or superheating
steam previous to allowing it to pass into the cylinder of the engine.
In the accompanying Drawings we have shewn various views of the
several arrangements and forms in which our improvements may be carried
into effect.
In constructing locomotive boilers, we form a water space all round the
bottom of the fire-box, and connect this water space with the barrel or body
of the boiler by means of pipes; channels, or water spaces constructed of
any convenient shape, so as to obtain a circulation of the water from the
barrel or body of the boiler down to the bottom of the fire-box.
Fig. 1, Sheet I., represents a portion of a locomotive boiler shewn partly in
longitudinal section and partly in elevation, with our improvements adapted
thereto, aud shewing one method of connecting the water space under the
bottom of the fire-box with the barrel of the boiler, also shewing one of our
improved modes of superheating steam. Fig. 2 is an end elevation and
transverse section of the same taken through the fire-box. The water space
below the fire-box is seen at a, and communicates with the body or barrel
6 of the boiler by means of a passage or channel c, whereby a constant
circulation of the water is kept up throughout the boiler.
By constructing boilers in this manner all sediment will be carried down
into the coldest part of the boiler, from whence it can be easily cleaned out,
and therefore the liability of the boilers to foul or become coated is considerably

page_text: diminished. We also construct locomotive boilers with a chamber underneath
the barrel or body so as to receive all sediment from the said barrel or body,
and from this chamber it may be conducted into the water space under the
fire-box by means of tubes, channels, or spaces, as in Figures 1 and 2.
Figures 3 and 4 are sectional views, of a locomotive boiler, in which a
chamber is constructed, and extends longitudinally under the barrel b of the
boiler. This chamber is connected with the water space a under the fire-
box by means of the channel or pipe c, as in the former instance. For
insuring dry steam in boilers of this description we employ the second part
of our Invention, which relates to a novel mode of superheating steam.
In Figures 1 and 2 we have shewn one mode of superheating the steam in
multitubular boilers of the locomotive form. d, Figure 1, is a chamber
shewn in section, which extends from side to side of the fire-box. A series of
pipes e extend from this chamber through the upper row of boiler tubes,
which are enlarged for the purpose. These pipes are connected at the
opposite or smoke box end with two similar chambers not shewn in the
Drawing, but one of which is in communication with the upper part of the
steam space of the boiler, and the other, with the steam delivery pipe leading
to the cylinders of the engine or elsewhere. In order to protect the
chamber d (which is suspended in the fire-box) from the intense action of
the fire we enclose it in a jacket f, composed of fire-brick or any other
suitable material, and this jacket is continued downwards in front of the
open ends of the flue boiler tubes g, and has a series of orifices corresponding
with the ends of the boiler tubes formed in it for the purpose of allowing the
heat and gases from the fuel to pass through to the flue or boiler tubes g.
In Fig. 3 a modification of the above arrangement is shewn.
chamber suspended in the fire-box is in this instance protected by being
surrounded with a water space or chamber f in the place of the fire-brick
jacket f, shown in Fig. 1. The steam pipes e in the flue tubes g are cou-
nected with the boiler by means of a cock, so that water may be admitted
into these pipes while getting up steam, or while the engine is stationary
for any length of time. By this means the suspending pipes are made
part and parcel of the boiler. A cock or valve. is also adapted at some
convenient place beween the boiler and the superheating tubes in order to
shut off all communication with the boiler in case of accident to the super-
heating apparatus, and we sometimes carry these tubes in the shape of a
coil or otherwise over the top of the fire.
The
Fig. 5, Sheet II., is a longitudinal vertical section; Fig. 6 is a horizontal
section, and Fig. 7, a transverse section taken at the smoke-box end of a

page_text: locomotive boiler, to which our superheating apparatus is applied; h is the
main steam pipe for conveying 'the steam from 'the steam space of the boiler
through the cock i into the chamber j, shewn in Figures 6 and 7. The steam
passes from this chamber through the pipes k,'in the boiler tubes e, into the
chamber c'in the fire box; from whence it passes back through'n'second series
of tubes, also arranged within the boiler tubes e, to the chamber',* placed in
the smoke box, and from this chamber the dry steam is conveyed by the
pipe m to the cylinders of the engine, as shewn in Figures 5, 6, and 7. By
this arrangement, the steam 'will be highly'superheated before it reaches the
cylinders, and should any priming occur in the boiler, and water thereby be
carried into the steam pipe, it will, by the heat' in the tubes e, be converted
into stenni before reaching the cylinders. By these' means a greater effective
power will be obtained from the engines, and a considerable economy in water
and fuel will be effected. In order to prevent the superheating pipes from
being burnt while the engines are standing still, or during the process of
getting up steam, these superheating pipes are connected by a pipe and cock
with the water space of the boiler so that they may be filled with water;
when desired a suitable cock is also provided for the purpose of discharging
this water previous to starting the engines. Suitable cocks' may also be
provided for the purpose of cutting off all communication with the boiler in
case of accident, and the parts are also 'so arranged that the engines may be
worked either with superheated or non-superheated steam, as" may be
preferred.
04
i.
"When the superheating apparatus is 'not required, or while steam' is being
generated, the feed water for the boiler is passed through the superheating
tubes, and thereby becomes heated before entering the body of the boiler, but
When the superheating apparatus is required, the communication between this
and the feed water must be cut off,' and nothing but steam allowed to enter
the tubes. We also employ additional feed water tubes which will come in'
use when the superheating tubes are required for drying the steam.
In constructing 'vertical boilers for marine' or stationary purposes, or for
portable engines, we construct an additional water space at the upper part
of the 'fire-box, and' connect the same with another' water 'space which
extends from side to side of the file box, and over the top of the fire, and
forms a kind of ring. Our object in this arrangement 'is to obtain a large
amount of surface within a small space, and a perfect circulation of water
throughout the boiler.
•
Fig. 8, Sheet I., is a vertical section of an upright boiler constructed in this
manner; 'and Fig. 9 is a horizontal section of the same; taken in the line A, B,

page_text: This
of Fig. 8. n is the additional water space, which is of a circular form, as
shewn in the sectional plan, Fig. 9. The water space n is suspended in the
upper part of the fire-box, and communicates with the boiler b.
additional water space is also connected at the bottom with another water
space o, extending from side to side of the fire-box, and this latter is connected
with the main water space of the boiler 6. The object in this arrangement is
to ensure water being kept in the additional water space n. By this arrange-
ment also the sediment is carried down to the lower part of the boiler, thus
preventing the water spaces over the fire from being burnt.
Tubes P, P.
connect the outer fire-box or space with the central one, so as to cause a
current of hot air to pass through from the outer space to the inner one, and
from thence to the main flue tubes e of the boiler. These tubes are fixed in
the side of the central water space, as shewn at Fig. 8. The flue tubes being
arranged in this peculiar manner will cause the hot air to take a more
circuitous route in place of passing straight to the chimney. It will be quite
clear, that if the outer fire-box, space; or chamber were not connected with
the inner one by the lateral tubes p, p, the central space would act as an
extinguisher, as there would be no circulation of air through it, and this
would, of course, prevent the surface from being effectually heated. q is a
mud-hole on the side of the boiler, for cleaning out the water space o, which
extends from side to side of the boiler. We would here remark that other
tubes of any suitable shape may be arranged so as to communicate with the
chimney.
In Fig. 10, Sheet I., two water spaces n, n*, are placed over the top of the
fire, and communicate with the body of the boiler b. From the bottom of
these water spaces extend other water spaces o, o, which are attached to tho
sides of the fire-box, and communicate with the main water space 6 of the
boiler. The main object of this arrangement is to obtain a free circulation
of water, as in the former instance. In Fig. 8, e is a flue tube extending
up from the central space to the smoke-box; and p, p, are tubes connecting
the central space with the middle one, so as to obtain a circulation of hot air
up through the tube e, as in Fig. 8. e*, e, are flue tubes connected to the
outer fire-box or space, in order to obtain a circulation of hot air through this
outer fire-box or space; fis a superheating chamber or steam dome placed in
the smoke-box on the top of the boiler, and is provided with tubes g* to cause
the hot air and gases to dry the steam therein before allowing it to enter
the engines. It will be sometimes convenient to construct a water space
under the fire-box, as above described in reference to the locomotive boiler,
and outside the vertical boilers is to be placed a wrought or cast iron shell

page_text: lined with fire-bricks, so as to form a flue, through which the heat may be
carried round the outside of the boiler as well as in the fire-box. In order to
dry or superheat the steam, a pipe or pipes are arranged in coils round this
flue, and the steam from the boiler is conducted through the beated coils
before entering the engine. This arrangement is shewn in Figures 11 and 12,
Sh eet I., in which 6 is the body of the boiler, and 6* is a metal jacket or
casing enclosing the whole of the boiler. This casing is lined with fire-bricks b*,
or any other suitable material; short flue tubes p, p, pass through the narrow
part of the water space of the boiler, and communicate with the flue space
between the outside of the boiler and the brickwork, as shewn in the Figures.
By this arrangement the whole of the heat from the furnace is made to pass
over the whole of the exterior of the boiler before arriving at the chimney.
The narrow part of the water space is continued downwards under the fire-
box, so as to collect the sediment, as in the former instances. A steam
pipe h passes up into the upper part of the steam space of the boiler, and
is provided with a cock *. This steam pipe is continued in a coil round
the boiler in the flue space e, where it is heated for the purpose of acting
as a superheater, or for heating the feed water.
In another form of vertical boiler we construct an additional heating
chamber, which is placed horizontally over the fire-box, and is connected on
each side with the water spaces of the boiler, so as to obtain a perfect cir-
culation of water throughout the boiler. It will sometimes be found con-
venient to pass tubes or chambers through this additional heating chamber,
in order to obtain a large amount of heating surface within a small space.
This boiler is also constructed with a water space under the bottom of the
fire-bars, so that all the sediment may settle at the coolest part of the boiler.
Fig. 13, Sheet I., is a vertical section of an upright boiler of this kind;
and Fig. 14 is a horizontal section of part of the same. 6 is the body part of
the boiler; 6,6*, is a horizontal barrel or chamber extending from side to
side of the fire-box, and communicating with the main water spaces of the
boiler; c, c, are vertical chambers projecting up into the water space of the
borizontal barrel or chamber, so as to obtain a large amount of direct heating
surface in a small space. Before arriving at the chimney the heated gases
will have to travel round the horizontal barrel or chamber b* and the vertical
chamber c, and up through the pipes f, f, as shown in Fig. 13. By means of
the pipes f,f, the hot air is made to circulate in and pass through the vertical
tubes or chambers c, and thereby beat the surfaces thereof. We also propose
to arrange chambers transversely over the top of the fire, and projecting into
the horizontal tube 6 parallel to the sides thereof, as shewn in the horizontal

page_text: sectional view, Fig. 15, or tubes may be passed up vertically into 'the
chamber if found desirable. The boiler is also constructed with a water space
under the fire-bars in a similar manner to that described in Fig. 11, and for
the same purpose. Additional heating surface may also be obtained by con-
structing vertical boilers with a'chamber or barrel extending from side to side
of the fire-box over the top of the fire,and fitted with tubes passing horizontally
through it, and fastened to the outer shell of the boiler." A smoke-box is also
placed opposite to the ends of the tubes of each boiler; for the purpose of
causing the whole of the heat and gases to pass through them before going
into the chimney. In order to connect the smoke-box with the fire-box, tubes
are passed through the water space of the boiler; the 'smoke box may also be
made with a water space all round it to boil the salt water, or for the purpose
of heating the feed water; or they may be supplied with distilled water, so
that when the boiler is used for marine purposes, hot distilled water may be
supplied to the boiler without the aid of an auxiliary boiler. By this means
any losses from leakage; condensation, and other causes may be provided for.
Fig. 16, Sheet I., is a vertical section of an upright boiler provided with a
horizontal tubular chamber or water space, extending from side to side of the
fire-box,and having tubesc passing horizontallythrough the same and fastened
into the outer shell of the boiler, thereby opening a communication between
the smoke box e and e* on each side of the barrel b*; the outer casings e³, e³,
of the smoke boxes are formed into tanks for heating the feed water. These
tanks may also be used when the boiler is applied to marine work for heat-
ing and supplying distilled water to the boilers. In order to connect the
smoke box with the fire-box, short tubes g are passed through the water
space of the boiler, and the heated gases will, in escaping to the chimney,
pass through the tubes g into the smoke box e, and back through the tubes c
in the smoke box or chamber e*. The superheating tubes 'shown in Figures 5,6,
and 7, may, if desired, be inserted in the horizontal tubes c, c, which pass
through the additional water space 6. A water space may be made under the
bottom of the boiler; as shewn in Figures 11 and 13, and already described.
Fig. 17 is a transverse section, taken through the chamber b*, showing
the tube c.
'
'
vie
"
We sometimės make an outer casing with a water space to surround loco-
motive boilers or tubular boilers, and pass tubes through the water space of
the boiler, so as to cause the heat and gases to pass round the outer casing
of the boiler, for the purpose of 'heating the water in 'the water casing.
Fig. 18, Sheet I., is a sectional view, taken through the fire-box of a loco-
motive boiler, constructed on this principle. b is the outer casing enclosing the

page_text: whole of the boiler. The short tubes g that pass through the water space in
the sides of the fire-box may be fitted with valves or slides to regulate the
temperature of the water in the casing. The superheating tubes may also be
adapted to the flue tubes e, e, in this form of boiler; and we would here have
it distinctly understood that we do not claim the exclusive use of the hollow
stays or tubes g which pass through the water space of the boiler, as such
stays have been in use for a considerable time for similar
purposes.
Fig. 19 is a sectional view of a boiler, somewhat of the form represented at
Fig. 18, shewing the superheating chambers c*, c*, connected by tubes k, k,
and arranged on the outside of the fire-box casing which is enclosed by an
exterior jacket 6*, as in Fig. 18, for the purpose of keeping the superheating
chambers c, c, hot.
I
In constructing high-pressure marine, locomotive, and stationary boilers, we
construct on the top of the boiler a long tube or chamber for the steam to rise
iuto from the boiler, and in order to heat the same in this chamber, the whole
or a portion of the heat from the fire may be passed through a series of tubes
arranged inside this chamber on the top of the boiler. This chamber comma-
nicates with a smoke-box at one end of the boiler, and. at the other end. it is
fitted' with a smoke-box communicating with a flue or uptake from the top of
the furnace or fire-box. The two smoke-boxes in the boiler are also fitted
with dampers, so as to regulate the heat in the chamber and the temperature
of the superheated steam, as is found desirable in practice.
"Fig. 20, Sheet II., is a longitudinal vertical section, and Fig. 20ª is a trans-
verse section, of a boiler constructed upon this plan, for traction engines or
locomotive and high-pressure marine engines. is a horizontal tubular
chamber,.placed longitudinally on the top of the boiler b, and connected thereto
by short vertical pipes or flues. The interior of the chamber c is fitted with
longitudinal flue tubes e, and at each end of the chamber c is a smoke-boxf
and f; the latter is connected with the ordinary smoke-box of the boiler,
and the other smoke-box fis connected with the furnace or fire-box by a short
tubularflue d. To the smoke. boxes fand f* are attached dampers d*,by regu-
lating which a portion of the heated gases may be made to pass into the smoke-
box fand through the flue tubes e into the smoke-box f* and from thence
up the chimney, by which means the steam in the tubular chamber c will
become highly superbeated. The dampers will also afford the means of
regulating the temperature of the steam in the chamber o, c.
In the ordinary form of marine steam boiler steam tubes may be introduced
into the tubes of the flue boiler for the purpose of superheating the steam, as
described in our, other forms of boilers. It will also, sometimes be found con-

page_text: venient to place a chamber or vessel of any shapeinside theboiler. This chamber
is divided into two compartments, and one end of the chamber is connected
with the top of the combustion chamber or fire-box, and the other end is
connected with the uptake or chimney of the boilers; the outer envelope is
for the heat and gases to pass through into the uptake, and the inner
chamber is for steam space, which steam is thereby surrounded with heated
gases, and therefore becomes highly superheated.
Fig. 21, Sheet II., shews the superheating apparatus arranged in the form
of a chamber placed in the interior of the boiler. h is the steam pipe lending
from the steam dome to the superheating chamber c, from which the steam is
taken by the pipe m through the stop valve m*to the cylinders of the engines.
The hot air and gases are taken from the combustion chamber or fire-box by
the pipe or passage f* into the annular space g of the superheating apparatus,
and by this means are made to encircle the whole of the interior compartment
of the superheating tubes, and finally to escape into the uptake through the
openings g. The passage f* may be fitted with a damper to regulate the
heat, as may be found desirable. The superheating apparatus is also by this
arrangement easily protected from injury during the process of raising steam,
and on other occasions when such care is required. The superheating
arrangement shewn in Figures 5, 6, and 7, may also be adapted to this
form of boiler.
Fig. 22, Sheet II., is a plan on an enlarged scale, shewing the way in
which our tubular superheating apparatus is arranged and constructed. The
steam is taken into the chamberjati, and from thence it passes through the
tubes into the chamber c*, returning back through the tubes into the
chamber placed together with the chamberjin the smoke-box of the boiler,
the chamber c being placed in the fire-box,as shewn in Figures 5,6,and 7. The
steam is taken from the chamber* by the outlet pipe m to the steam cylinders.
In the Figure the tubes are shown connected by socket and back nuts, and
also by flanges, but we do not mean to confine ourselves to any particular mode
of connection or material of construction. The arrangement for filling the
tubes with water has been previously described in reference to Figures 5, 6,
and 7, Sheet II., and therefore need not be repeated here. We would here
distinctly explain that we use the same arrangement of tubes and chambers
both for superheating the steam and for heating the feed water, and valves
suitable for facilitating the execution of each of these operations are placed
between the chambers and the boiler.
Fig. 23,Sheet I, represents a longitudinal section of a Cornish boiler with
internal flue,inwhich the tubular superheating apparatus described in previous

page_text: Figures is arranged. Fig. 24 is a cross section of the same. A plain tube or
chamber, such as that shewn in Fig. 25 may, however, be employed in place
of the tubular arrangement, if preferred, or if desired a number of tubes
may be inserted within the chamber, as shewn in Fig. 26.
Fig. 27 is a longitudinal section of the smoke-box end of a locomotive
boiler. Fig. 28 is a transverse section of the same. In this arrangement the
tubular superheating apparatus is employed in combination with the chamber
c,in order to obtain a larger amount of dry steam. For the purpose of causing
the whole of the hot air and gases to pass through this chamber,the main flue
tubes e of the boiler are prolonged so as to connect them with the tubes o*
of the chamber o; or the tubes e* of the chamber may be prolonged so as
to fit into the flue tubes e of the boiler. By these arrangements facility
in cleaning the tubes is obtained.
Having now described our several improvements, and having explained
the manner of carrying the same into effect, we would observe that although
in order that our various improvements may be more clearly understood, we
have described and have shewn in the accompanying Drawings various
parts of steam boilers which have been before known and used for analogous
purposes, yet we do not mean or intend to claim any such well-known parts;
but that which we consider to be new and desire to claim as the Invention
secured to us by Letters Patent as aforesaid, is,-
First, the mode herein set forth of constructing steam generators.
Second, the mode herein set forth of superheating steam and arranging
the apparatus to effect this object.
Third, we claim the mode herein set forth of heating the feed water of
steam generators.
In witness whereof, I, the said Thomas Cresswell, have hereunto set
my hand and seal, the Twelfth day of November, in the year of
our Lord One thousand eight hundred and sixty.
0
Witness,
J. W. MOFFATT,
66, Chancery Lane.
THO CRESSWELL. (L.s.)