IMPROVEMENTS IN STEAM ENGINES AND BOILERS
Year: 1862

page_text: LETTERS PATENT to James Howden, of Glasgow, in the County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN STEAM ENGINES AND BOILERS,"
Sealed the 4th July 1862, and dated the 4th January 1862.
PROVISIONAL SPECIFICATION left by the said James Howden at the
Office of the Commissioners of Patents, with his Petition, on the 4th
January 1862.
I, JAMES HOWDEN, of Glasgow, in the County of Lanark, North Britain,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE.
MENTS IN STEAM ENGINES AND BOILERS," to be as follows, that is to say:-
This Invention relates to various improvements in the arrangement and
working of steam engines and boilers, and in various details thereof, by
which great economy, simplicity, and efficiency is obtained.
One improvement in double expansive engines,according to this Invention,
consists in placing the high and low pressure cylinders alongside each other,
with their axes parallel, the steam being admitted to both cylinders by one
valve only, by which means the loss in economy arising from the great
reduction of pressure in the steam, when passing from the high to the low
pressure cylinder is prevented. This is carried out in one modification by
Pine 81

page_text: having a working face for the valve on both cylinders, the faces being
parallel; a part of the valve and one of the faces is moveable on the other
part, so as to allow both valve faces being kept tight by the steam on their
respective cylinder faces. The steam is first admitted to the high-pressure
cylinder, and after performing its work therein, is passed directly through
the valve to the low-pressure cylinder, and in course finally discharged
therefrom by the same valve. This valve is also relieved from the pressure
of the steam on the area of its body, the moveable face being jointed to the
other part of the valve, as in the system for which I have already obtained
Letters Patent, bearing date the 21st November 1860, No. 2854. To attain
the utmost economy, it is preferred to have the valve in. the manner of two
short coupled slide valves, one at each end of the cylinder, so as to reduce
the length of the steam ports to a minimum. The great reduction of the
pressure of the steam between the two cylinders may also be carried out,
according to this Invention, by having a valve with one face only for work-
ing the two cylinders. This face is on the low-pressure cylinder, from
which a passage or passages extend by the side or sides of the valve chest
to the high-pressure cylinder. The valve first admits the steam to the high-
pressure cylinder, and then admits the same to the low-pressure cylinder,
and thereafter to the exhaust port. When the valves here described are
applied to engines where the high and low pressure pistons travel simu-
taneously in the same direction, that part of the valve admitting steam to the
upper end of the high-pressure cylinder is placed at the lower end of the
low-pressure cylinder, and that part admitting steam to the lower end is
placed at the upper end of the cylinder.
Another improvement according to this Invention in double expansive
engines consists in working one or more high-pressure cylinders on the end
of a low-pressure cylinder with one valve. This is effected by having the
whole of the ports arranged on the low-pressure cylinder face, the two high-
pressure ports being together at that end where the high-pressure cylinder
or cylinders are attached to the low-pressure cylinder, the three usual ports
of the low-pressure cylinder being immediately contiguous to the other two
ports. The outside port of the high-pressure cylinder or cylinders is in
connection with the side or sides of the piston or pistons nearest to the low-
pressure cylinder. The valve covers the whole of the ports, and gives steam
from the boiler alternately to the two high-pressure ports through a port in its
face communicating with the valve chest at one or both sides of the valve.
When steam is admitted from the valve chest by the port in the valve

page_text: already described to the side or sides of the piston or pistons nearest to the
low-pressure cylinder, the outer sides of the high and low pressure pistons
are put in communication with each other by means of two ports in the valve
face and a passage inside of it, the inner side of the low-pressure piston being
at the same time put in communication with the exhaust port. When by
the motion of the valve the outer side or sides of the high-pressure piston or
pistons receive steam direct from the valve chest, the inner sides of the high
and low pressure pistons are put in communication by another port in the
face of the valve (also in communication with the inside passage), and one
of these already mentioned, the outer side of the low-pressure system being
then open to the exhaust pipe.
Another improvement according to this Invention consists in a novel and
simple method of working "cut-off" valves. This is accomplished by having
a plate or plates on the back of the common slide valve, ports for the admission
of steam to the cylinder being through the valve in the usual manner. These
plates are held on the back of the valve by the pressure of the steam, but
they may also be held partly by springs. On the back of the plates are
projections, which, when the plates are moved by being in contact with the
valve, come in contact with projections on a rod so placed as to move the
plates over the ports in the valve and cut off the steam from the cylinder.
When the valve moves in the contrary direction, other or the same
projections move the plates off the ports in the valve, and leave them open for
the admission of steam to the cylinder. This process is carried on alternately
at each end of the valve, when two plates and two ports are used, but steam
may be admitted by one port, and cut off from both ends of the cylinder by
one plate. The projections on the rod for working the "cut-off" plates are
capable of being adjusted from the outside, while the engine is at work so as
to cause the "cut-off" to take place at various parts of the stroke. In this
arrangement described, the "cut-off" plates have their motion in the same
direction as the valve, but by a slight modification they may be made to
have motion at right angles to the motion of the valve; when working as
described, the motion of the plates is wholly derived from the motion of the
valve, the rod having the projections being stationary, but in some cases this
rod may also have a motion for the purpose of giving a quicker set-off.
Another improvement according to this Invention consists in so working
the air condensers for which I obtained Letters Patent bearing date the 21st
November 1860, No. 2854, (the condensing medium being air forced through
or among the tubes of a surface condenser by a fan or other instrument, the

page_text: heated air carried off being used for the boiler furnaces or other purposes,)
that a lesser quantity of air is required for maintaining a vacuum, and a high
temperature imparted to the air before passing to the boiler furnace, or where
it may otherwise be made use of. This is effected by having two condensers
or one with two divisions. The steam is exhausted from the cylinder into
what may be called the hot condenser during the time the crank is turning
the "dead points," when the piston begins the return stroke the cylinder is
shut off from the hot condenser, and put in communication with the cold or
vacuum condenser during the length of its stroke. The air is first forced
through the cold condenser and then through the hot condenser in its
passage to the boiler furnace, or where it may be otherwise usefully applied.
Further improvements consist in first exhausting the steam into pipes or
chambers for heating or other purposes instead of the hot condenser, the
cylinder afterwards being put in communication with the vacuum condenser
as described. This last improvement may also be carried out with engines
using the common jet or surface condenser. To facilitate the application of
the air condenser to existing non-condensing engines, a single pump, act-
ing on one side as an air pump and on the other side as a feed pump, may
be used to pump the air and water from the condenser and feed the boiler
with the water. It is also preferred in most cases, where the engine is not
of a large size, to have the condenser horizontal or nearly so, the air being
forced direct through the tubes.
Another improvement in steam engines according to this Invention refers
to the construction of refrigerators for cooling the water pumped from the
condenser for the purpose of reinjection. These improvements are carried
out by arranging several divisions of tubes, each division consisting of one
or more rows of tubes fixed at each end in tube plates, the whole being
contained within a strong vessel of cast or malleable iron. The water from
the condenser is pumped to and fro through the inside of the tubes in the
several divisions until it arrives cooled at a cistern open to the atmosphere,
to which the injection pipe is connected. The cooling water is forced
through a like number of divisions on the outside surfaces of the tubes in
a contrary condition to the water inside the tubes. It is preferred to make
the divisions inside the tube plates between the several series of tubes for
giving the proper currents to the cooling water of wood, to withstand the
deleterious action of salt water.
On the top of the cistern to which the injection pipe is attached a self-acting
valve is placed, so as to give free access of air to the cistern, but which closes

page_text: when the water rises to the top of the cistern (as when "blowing through "
the condenser previous to starting the engine), and not only prevents the loss
of water, but forces the injection water into the condenser against a pressure,
as in the case of the vacuum being destroyed by the heating of the condenser.
The improvements in steam boilers according to this Invention refer
partly to the manner of constructing and partly to improved modifications of
that kind of boiler for which I obtained Letters Patent bearing date 21st
November 1860, No. 2854, and which is composed of small tubes connected
to chambers at each end, water or water and steam being in the tubes and
chambers, steam or steam and water being also held in cylindrical vessels
connected to the chambers.
One portion of these improvements consist in one case in making the
chambers with which the tubes are connected of a rectangular section, and
having the outside plate, which is opposite to the tube plate of each chamber,
fastened by bolts or other moveable fastenings, so that for cleaning and repairs
these plates or doors may be speedily removed (thereby giving free access to
the ends and inside of the tubes) and also speedily replaced and fastened.
These chambers may also be of a semicircular section, the semicircular part
being the removeable door and bolted to the flat tube plate, instead of both
chambers having moveable doors one only may be constructed in this manner.
Another improvement consists in binding the doors together by rods
passing through the tubes, so that the pressure on the outside plates or doors
is resisted by the tensile strength of the rods, as well as by their own fasten-
ings. These tie rods may also be used where the chambers have no move-
able doors to strengthen the chambers, and resist the tendency of the
pressure to separate them from the tubes.
Another portion of improvements consists in having a thin moveable plate
on the tubes, for keeping their outside surfaces free of soot or deposit from the
fire
gases, this loose plate can be moved from end to end of the tubes so as to
scrape their entire surfaces.
For large boilers this plate may be made in
several pieces. The improved arrangements of these boilers according to this
Invention consist, in one case, in having the boiler on which the fire gases act
in three parts, each composed of tubes and chambers as described; one of
these parts is placed on each side of the fire grate, and one over the fire grate,
the top rows of tubes in each part being on or about the same level, the tubes
in each part lying horizontal or nearly so. The chambers of the part over the
fire grate lie horizontally in the direction of their length, while the chambers
of the parts on each side are perpendicular, and with their tubes extend con-
siderably below the level of the grate bars. The fire grate is about the same

page_text: length as the tubes, and has sides of brick or other material between the grate
and tubes. It is preferred to maintain the level of the water in the boiler
when working about the lower side of the upper rows of tubes. To prevent
the action of the fire gases on these tubes and above the water level, thin tiles
of fire brick or sheet plate, or both together, are used. Over the tubes and
in connection with the chambers, at one or both ends, are the cylindrical
steam vessels. The whole boiler is enclosed in a casing of iron and brick
or other suitable material.
The fire gases act first on the tubes over the fire-grate by radiation, and
then pass to each side and downwards through among the tubes, passing
at the bottom through a suitable passage or passages to the chimney. The
feed water is admitted at the bottom of the chambers on each side of the
grate, the part over the grate receiving feed water from the other two.
Instead of the part over the grate, composed of tubes and chambers,
cylindical vessels may be used containing a water and steam space. The
fire gases act first on their under surfaces and then pass among the tubes
on either side. With a slight modificatiou this boiler may be arranged that
the fire gases from the grate pass upwards among the tubes and about the
steam receivers, if required, before passing to the chimney. For boilers of
small sizes, one part only, composed of tubes and chambers, may be used,
with a cylindrical vessel over the fire grate partly filled with water, the
fire gases acting first on the under side of the vessel, and then passing
down among the tubes as described to the chimney.
These arrangements of boilers described may be still further modified by
having two or more separate parts composed of tubes and chambers above
each other, joined by pipes or other connections, it being preferred to have
all the chambers lying horizontally as well as the tubes. The fire gases
pass along from the fire grate among the tubes in one part, returning
among the tubes of the other part, a division being put between the parts
to give the proper currents to the fire gases.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Howden in the Great Seal Patent Office on the
4th July 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
"HOWDEN, of 'Glasgow, in the County of Lanark, North Britain, Engineer,
send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of January, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Howden, Her special licence that I, the said James Howden,
my executors, administrators, and assigns, or such others as I, the said
James Howden, my executors, administrators, and assigns, should at any
time agree with; and no others, from time to time and at all times thereafter
during the terin therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
STEAM ENGINES AND BOILERS," upon the condition (amongst others) that I,
the said James Howden, executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particu.
larly 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 James Howden, 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 in writing reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say :-
My said Invention relates to various improvements in the arrangement
and working of steam engines and boilers, and in various details thereof,
by which great economy, simplicity, and efficiency are obtained.
One improvement in double expansive engines according to this Invention
consists in placing the high and low pressure cylinders alongside each other,
with their axes parallel, the steam being admitted to both cylinders by one
valve only, by which means the loss in economy arising from the great
reduction of pressure in the steam when passing from the high to the low-
pressure cylinder is prevented. This is carried out in one modification by
having a working face for the valve on both cylinders, the faces being parallel;
a part of the valve and one of the faces is moveable on the other part, so as to
allow of both valve faces being kept tight by the steam on their respective
cylinder faces. The steam is first admitted to the high-pressure cylinder, and
after performing its work therein is passed directly through the valve to the
low-pressure cylinder, and in course finally discharged therefrom by the

page_text: same valve; this valve is also relieved from the pressure of the steam on
the area of its body, the moveable face being jointed to the other part of
the valve as in the system for which I have already obtained Letters Patent,
bearing date the 21st day of November 1860, No. 2854. To obtain the
utmost economy it is preferred to have the valve in the manner of two
short coupled slide valves, one at each end of the cylinder, so as to reduce
the length of the ports to a minimum.
In Figure 1, Sheet 1, of the accompanying Drawings, A is the high-pressure
cylinder; B, the low-pressure cylinder; and C, the valve chest, in an arrange-
ment of engine as now described, the pistons being connected to crank-
diametrically opposite or nearly so; a, a, being the coupled slide valves, and
b, 61, their respective movable faces, both valve and loose faces being kept
tight against the cylinder faces by the steam pressure, while the body of the
valve is at the same time relieved from the steam pressure. Steam is being
admitted to the upper side of the high-pressure piston at the port c, whilst the
steam from the under side of the same piston is passing to the under side
of the low-pressure piston across through the valve by the ports d and e
The steam from the upper side of the low-pressure piston having done its
duty in both cylinders is escaping to the condenser by the ports f and g.
The great reduction of the pressure of the steam between the two cylinders
may also be obviated according to this Invention by having a valve with
one face only for working the two cylinders. This face is on the low-pressure
cylinder, from which a passage or passages extend by the side or sides of
the valve chest to the high-pressure cylinder. The valve first admits the
steam to the high-pressure cylinder, and then admits the same to the low-
pressure cylinder and thereafter to the exhaust port.
In Figure 2, Sheet 1, of the accompanying Drawings, A is the high, and B
the low-pressure cylinder; h, h¹, is the coupled valve of this arrangement.
Steam is being admitted to the upper side of the high-pressure piston at the
port i, while the steam from the under side of the same piston is passing by the
lower part of the valve h'to the underside of the low-pressure cylinder through
the portsj, k. From the upper side of this piston the steam is exhausting to
the condenser by the ports 1, m. In engines where the high and low pressure
pistons travel simultaneously in the same direction, that port of the valve
admitting steam to the upper end of the high-pressure cylinder is placed at
the lower end of the low-pressure cylinder, and that port admitting steam
to the lower end is placed at the upper end of the low-pressure cylinder.
Another improvement according to this Invention in double expansive

page_text: engines consists in working one or more high-pressure cylinders on the endof
a low-pressure cylinder with one valve. This is effected by having the whole
of the ports arranged on the low-pressure cylinder face,as shown in Figure 3,
Sheet 1, of the accompanying Drawings, which is such an arrangement with
one high-pressure cylinder A connected to the low-pressure cylinder B,the
piston rod D connecting their two pistons, the power being communicated to
the shaft through the connecting rod E, in working connection with two
piston rods from the low-pressure cylinder B on each side of the high-
pressure cylinder A. The valve F covers the whole of the ports and gives
steam from the boiler alternately to the two high-pressure cylinder ports n,n,
0,0, through a port p in its face communicating at one or both sides with the
valve chest C. When steam is admitted from the valve chest by the portp of the
valve to the side of the piston nearest to the low-pressure cylinder, the outer
sides of the high and low pressure pistons are put in communication with each
other by means of two ports q,, in the valve face and a passage s inside of it,
the inner side of the low-pressure piston being at the same time put in com-
munication with the exhaust port, as shown in the Drawing. When by
the motion of the valve F the outer side of the high-pressure piston receives
steam direct from the valve chest C by the ports p and o, the inner sides of
the high and low pressure pistons are put in communication by the ports
t and g of the valve, connected with each other by the passage inside the
valve. The outer side of the low-pressure piston is then open to the
exhaust port.
Another improvement according to this Invention consists in a novel and
simple method of working "cut-off" valves. This is accomplished by having
a plate or plates on the back of the common slide valve, ports for the admis-
sion of steam to the cylinder being through the valve in the usual manner.
These plates are held on the back of the valve by the pressure of the steam,
but they may also be held partly by springs. On the back of the plates are
projections, which, when the plates are moved by being in contact with the
valve, come in contact with projections on a rod so placed as to move the
plates over the ports in the valve, and cut off the steam from the cylinder.
When the valve moves in the contrary direction, other or the same projections
move the plates off the ports in the valve, and leave them open for the
adinission of steam to the cylinder. This process is carried on alternately at
each end of the valve when two plates and two ports are used, but steain
may be admitted by one port and cut off from both ends of the cylinder by
one plate, The projections on the rod for working the "cut-off" plates are

page_text: capable of being adjusted from the outside while the engine is at work, so
as to cause the "cut-off" to take place at various parts of the stroke. This
system of working "cut-off" valves is shown in Figures 4 and 5, Sheet 1, of
the accompanying Drawings as applied to a pair of inverted cylinder engines.
G, G¹, G", G, are the cut-off plates ou the back of the slide valves H,
H; I is the adjustable rod with the projections or collars u, u, u", "1.
The valve H is on its downwards stroke, and the plate G, detained by the
collar ul, cuts off the steam from the cylinder A, by shutting the port vin
the slide valve H. In the upward stroke of the valve the plate G, carried
along with the valve, comes in contact with the upper collar u on the rod I,
and the valve continues its motion until the port is opened to admit the
steam on its downward stroke before being cut off by the plate coming in
contact with the collar u¹, as already described. The plate at the lower end
of the valve is worked exactly in the same manner by the collars ull,ull,and
also the plates G and G on the other valve H¹. By turning the hand
wheel J in one direction, the collars u¹, u", are brought closer to each other
to give a later "cut-off," and by turning in the contrary direction they are
set further apart, and give an earlier "cut-off." This adjustable motion is
simply effected by having the thread of the pin and socket screw, which con-
nects the upper and lower parts of the rod I, twice the pitch of the thread
of the screw w on the upper part of the rod. The lower part of the rod I
is prevented from turning round by a square pin fitting in a suitable socke
in the casting. In Figure 5 of the Drawings an arrangement is shown
whereby the "cut-off" plates are kept against the back of the slide valves
by bars pressed against them at each end by internal springs contained in
boxesx,xl, which also hold the bars in position. In the arrangement described
the "cut-off" plates have their motion in the same direction as the valve,
but by a slight modification they may be made to have their motion at right
angles to the motion of the valve. When working as described the motion
of the plates is wholly derived from the motion of the valve, the rod I being
stationary, but in some cases this rod may also have a motion for the purpose
of giving a quicker "cut-off."
Another improvement according to this Iuvention consists in so working
the air condensers, for which I obtained Letters Patent, bearing date the 21st
day of November 1860, No. 2854, (the condensing medium being air forced
through or among the tubes of a surface condenser by a fan or other instru-
ment, the heated air carried of being used for the boiler furnaces or other
purposes,) that a lesser quantity of air is required for maintaining a vacuum,

page_text: and a higher temperature imparted to the air before passing to the boiler
furnace, or where it may otherwise be made use of. This is effected by using
two condensers, or one having two divisions, one modification of which is
shown in Figure 6, Sheet 1, of the Drawings. The steam is exhausted from
the engine by the pipe K during the time the crank is turning the "dead
points" into the division L, which may be termed the hot condenser, the
valve M being then open, and the valve N shut. When the piston begins the
return stroke the cylinder is shut off from the hot condenser and put in com-
munication with the cold or vacuum condenser O during the length of its
stroke, the valve M. being now shut, and the valve N opened by the rod P,
actuated by the engine. The air is first forced through the tubes of the cold
condenser O, and then through those in the hot condenser L, in its passage
to the boiler furnace, or where it may otherwise be usefully applied. To
facilitate the application of the air condenser to existing non-condensing
engines, a single pump, acting on one side as an air pump and on the other
side as a feed pump, may be used. It is also preferred in most cases where
the engine is not of a large size to have the condenser horizontal or nearly so,
the air being forced direct through the tubes. Further improvements consist
in first exhausting the steam into pipes or chambers for heating or other
purposes, instead of the hot condenser, the cylinder being afterwards put in
communication with the vacuum condenser, as described. This last improve-
ment may also be carried out with engines using the common jet or surface
condenser.
Another improvement in steam engines according to this Invention refers
to the construction of refrigerators for cooling the water pumped from the
condenser for the purpose of reinjection. These improvements are carried out
by arranging several divisions of tubes, each division consisting of one or more
rows of tubes fixed at each end in tube plates, the whole being contained
in a strong vessel of cast or malleable iron. The water from the condenser
is pumped to and fro through the inside of the tubes in the several divisions
until it arrives cooled at a cistern open to the atmosphere, to which the
injection pipe is connected. The cooling water is forced through a like
number of divisions on the outside surfaces of the tubes iu a contrary direction
to the water inside the tubes. It is preferred to make the divisions inside the
tube plates between the several series of tubes for giving the proper currents
to the cooling water of wood, to withstand the deleterious action of salt water.
On the top of the cistern to which the injection pipe is attached a self-acting
valve is placed, so as to give free access of air to the cistern, but which closes
when the water rises to the top of the cistern, as when "blowing through"

page_text: the condenser previous to starting the engine, and not only prevents the loss
of water but forces the injection water into the condenser against a pressure,
as in the case of the vacuum being destroyed by the heating of the condenser.
One modification of a refrigerator embodying these improvements is shown
in Figures 7 and 8, Sheet 1, of the Drawings. The hot water pumped from
the condenser enters by the branch pipe Q, and passes to and fro through the
several series of tubes in the direction of the arrows until it arrives cooled at
the cistern R. The injection pipe S, by which the water again returns to the
condenser, is connected to the detached part R¹ of this cistern. The cooling
water enters by the branch pipe T,and passing upwards in the direction of the
arrows, is discharged at the branch U. The direction to the currents of the
cooling water is given by the wooden divisions V,V,V", and that of thewater
to be cooled by the bars W, W, W", inside the end covers of the refrigerator.
X is the self-acting valve, allowing admission of air to the cistern, but which
is closed by the ball y being floated into its seat should the water at any time
rise to the top of the cistern. It is preferred that this ball be made of wood
covered with gutta percha.
The improvements in steam boilers according to this Invention refer partly
to the manner of constructing and partly to improved modifications of that kind
of boiler for which I obtained Letters Patent, bearing date the 21st day of
November 1860, No. 2854, and which is composed of small tubes connected
to chambers at each end, water or water and steam being in the tubes and
chambers, steam or steam and water being also held in cylindrical vessels
connected to the chambers.
One portion of these improvements consists in one case in making the
chambers with which the tubes are connected of a rectangular sestion, and
having the outside plate, which is opposite to the tube plate of each chamber,
fastened by bolts or other movable fastenings, so that for cleaning or repairs
these doors or plates may be speedily removed (thereby giving free access to
the ends and inside of the tubes), and also speedily replaced and fastened.
These chambers may also be of a semicircular section, the semicircular part
being the removable door, and bolted to the flat tube plate. Instead of both
chambers having movable doors, one only may be constructed in this manner.
Another improvement consists in binding the doors together by rods passing
through the tubes, so that the pressure on the outside plates or doors is
resisted by the tensile strength of the rods as well as by their own fastenings.
These tie rods may also be used where the chambers have no movable doors
to strengthen the chambers and resist the tendency of the pressure to
separate them from the tubes.

page_text: In Sheet 2 of the accompanying Drawings, Figure 10 represents the manner
of constructing the chambers when rectangular with the doors fastened as
described, Y being the rectangular chambers connected by the tubes Z. z, z¹.
are the movable doors bolted to the body of the two chambers Y, Y. The
binding rods 1 pass through the tubes to each door; these rods are also
shown in the cross sectional view Figure 9; Figures 11 and 12 shew modi-
fications of the construction of the chambers, where the chambers are
composed of the tube plate and the movable doors only.
Another portion of improvements consists in having a thin movable plate on
the tubes for keeping their outside surfaces free of soot or deposit from the fire
gases; this loose plate can be moved from end to end of the tubes, so as to
scrape their entire surfaces. For large boilers this plate may be made in
several pieces. Figure 13 shews a modification of the movable scraping plate
as now described. The several parts 2, 2, are attached to the frame 3, so
as to allow of their being fitted on the tubes after that portion of the boiler
is constructed. The scraping plates are pushed along the tubes by rods
inserted through the chambers by the short tubes 4, 4, Figure 14.
The improved arrangements of these boilers according to this Invention
consist, in one case, in having the boiler on which the fire gases act in three
parts, each composed of tubes and chambers, as described. One of these
parts is placed on each side of the fire-grate, and one over the fire-grate; the
top rows of tubes in each part being on or about the same level, the tubes in
each part lying horizontal or nearly sc. The chambers of the part over the
fire grate lie horizontally in the direction of their length, while the chambers
of the parts on each side are perpendicular, and with their tubes extend con-
siderably below the level of the grate bars. The fire grate is about the
same length as the tubes, and has sides of brick or other material between
the grate and tubes. It is preferred to maintain the level of the water in the
boiler when working about the lower side of the upper rows of tubes. To
prevent the action of the fire gases on these tubes and above the water level
thin tiles of fire brick or sheet plates, or both together, are used. Over the
tubes, and in connection with the chambers at one or both ends, are the cylin-
drical steam vessels. The whole boiler is enclosed in a casing of iron and
brick, or other suitable material. The fire gases act first on the tubes over
the fire grate by radiation, and then pass to each side and downwards through
among the tubes, passing at the bottom through a suitable passage or
passages to the chimney. The feed water is admitted at the bottom of the
chambers on each side of the grate; the part over the grate receiving feed-
water from the other two.

page_text: Figures 15 and 16, Sheet 2, of the Drawings represent a boiler arranged
as in the modification described; Figure 17 shows one half of a boiler
similarly arranged, but with the water level in the cylindrical steam vessels.
Instead of the part over the grate composed of tubes and chambers, cylindrical
vessels may be used containing a water and steam space. The fire gases act
first, on their under surfaces, and then pass among the tubes on either side.
With a slight modification these boilers may be arranged so that the fire
gases from the grate pass upwards among the tubes and about the steam
receivers, if required, before passing to the chimney.
Figure 18, Sheet 2, of the Drawings shews one arrangement with the fire
gases ascending, but the position of the several parts of these boilers are
obviously capable of considerable modification. For boilers of small sizes one
part only, composed of tubes and chambers, may be used, with a cylindrical
vessel over the fire grate, partly filled with water; the fire gases acting first.
on the under side of the vessel, and then passing down among the tubes, as
described, to the chimney.
These arrangements of boilers described may be still further modified by
having two or more separate parts composed of tubes and chambers above
each other, joined by pipes or other connections; it being preferred to have all
the chambers lying horizontally as well as the tubes. The fire gases pass along
from the fire grate among the tubes in one part, returning among the tubes
of the other part, a division being put between the parts to give the proper
currents to the fire gases.
Figure 19 shows a modification of this lastly described arrangement,
with the fire gases descending in the direction of the arrows, and passing
from the boiler by the flue 5.
Having thus particularly described my said Invention, and the manner in
which the same is or may be used or carried into effect, I have to state that I do
not restrict myself to the precise details herein-before described and delineated;
but that what I consider to be novel and original and claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,-
First, the arrangements of cylinders and slide valves in double expansive
steam engines, as herein before described in connection with Figures 1, 2,
and 3, Sheet 1, of the accompanying Drawings.
Second, the arrangement of "cut-off" valves in steam engines, as herein-
before described in connection with Figures 4 and 5, Sheet 1, of the
accompanying Drawings.
Third, the improvements in air condensers, as herein-before described in
connection with Figure 6, Sheet 1, of the accompanying Drawings.

page_text: Fourth, the improvements in refrigerators, including the use of a self-
acting valve, as herein-before described in connection with Figures 7 and
8, Sheet 1, of the accompanying Drawings.
Fifth, the construction of steam boilers with movable doors, binding stays
and scraping plates, as herein-before described in connection with Figures 9,
10, 11, 12, 13, and 14, Sheet 2, of the accompanying Drawings.
Sixth, the improved arrangements of steam boilers, as herein-before
described in connection with Figures 15, 16, 17, 18, and 19, Sheet 2, of
the accompanying Drawings.
In witness whereof, I, the said James Howden, have hereunto set
my hand and seal, this Second day of July, in the year of our Lord
One thousand eight hundred and sixty-two.
JAMES HOWDEN. (L.S.)