IMPROVEMENTS IN STEAM GENERATORS, AND IN FURNACES THEREFOR
Year: 1870

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Southampton Buildings, London, Patent Agents, for
the Invention of "IMPROVEMENTS IN STEAM GENERATORS, AND IN FURNACES
THEREFOR." A communication from abroad by S. Lloyd Wiegand,
of Philadelphia. Pennsylvania. United States of America.
Sealed the 27th June 1871, and dated the 29th December 1870.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition, on
the 29th December 1870.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Southampton Buildings, London, Patent Agents, do hereby declare the
nature of the said Invention for “IMPROVEMENTS IN STEAM GENERATORS,
AND IN FURNACES THEREFOR," a communication, to be as follows:-
This Invention consists partly in forming boilers with their heating
surfaces composed of tubes suspended in the furnace from an upper
vessel or vessels in compartments so small as to render them safe from any

page_text: possibility of explosion, and making the compartments to communicate
with each other in such a manner that a circulation is maintained
through the several compartments, and an increased cleanliness of the
heating surfaces and the rapid and economical generation of steam are
insured.
In addition to the improvements above stated this Invention embraces
an improved form of cap or cup for the lower terminations of the
suspended tubes which afford larger space for the passage of the cir-
culating currents; also an improved connection for uniting the several
vessels, possessing great facility of application and renewal of joints and
great flexibility and durability when in use.
Included in this Invention is a mode of forming tanks of small cross
sectional area in folds or coils so as to cheaply make small portable
boilers with few joints, and a new mode of making a furnace in sections
or staves specially applicable to locomotive, marine, and river service in
conjunction with the steam generator herein described.
The upper
vessels or tanks of which this generator is composed are made in two or
more compartments, which are horizontal or nearly so, and of small cross
sectional area, and are directly over each other. The water is introduced
in the second compartment. The tubes forming the heating surfaces arc
inserted into the bottom of the lowest compartment. The lower ends of
the tubes are closed by screw caps of an inverted conical shape below
the screwed portion, and with channels opening upward through the
oblique sides of the cone from the apex or central portion of the conc.
The boshes formed by the oblique sides of the cone between the channels
serve to support in central position a guide for conducting a current of
fluid from the second compartment through a suitable aperture in the
bottom thereof downward to the bottom of the cap, whence the current
rises through the channels in the caps already described, and passing up
the annular space between tube and guide into the lowest compartment
of the tank. The guide for conveying the currents downward through
the centres of the tubes may be either a simple cylindrical tube open at
both ends, or may be made in the form of a spiral coil having a clear
central space or channel extending within the coils from the top to the
bottom, and having coils made inclined upward from the centre outward.
This form of coils deflects the descending current toward the centre and
the ascending current outward toward the tube in which the coil is
placed, thus avoiding any interference between the descending and

page_text: ascending currents. It also permits when the water level in the steam
generator has fallen into the tubes a flow of water to return from the
ascending column in the tube through the interstices between the coils
of the spiral guide to the descending column in the centre of the guide,
thus maintaining a circulation in the tubès after the water level has
fallen below the tank or upper vessel. An aperture or apertures in the
partition plate forming the bottom of the second compartment and the
top of the lower compartment made at a point or points remote from
the place of introduction of the feed water permits the current of mingled
steam and water which rises from the annular spaces in the tubes when
heat is applied to them to pass from the lower to the second compart-
ment of the tank where the steam separates from the water; or there
may be other chambers connected by suitable necks placed above the
second chamber into which the mingled steam and water rise, and
the steam is withdrawn from the highest part of the tank or vessel at a
point or points remote from the aperture communicating from the lower
compartment of the tank to the compartment above it. A flow of water
horizontally is produced towards the steam outlet in the upper com-
partment, and in the course of this flow the steam and water separate.
The separation of the steam and water is facilitated by placing oblique
obstructions or bars which are so inclined as to deflect the water and
allow the steam to pass over the top of them.
When a small boiler or steam generator is to be made it is formed
with one tank in the shape of a spiral coil in a horizontal plane with a
flue between the several coils thereof; or it may be made in folds in a
labyrinthian, annular, or other form, so as to make the tank of sufficient
length to afford a proper distance for the horizontal flow of the water in
the compartments or chambers of the tank, and at the same time to be
conveniently applicable to a furnace.
When a large generator is to be made it is best done by uniting a
number of tanks formed in compartments as herein-before described to
a common feed pipe and a common steam drum with flues between the
several tanks.
The device employed for connecting the tanks to the feed pipe and to
the steam drum is another feature in this Invention, a tubular return
bend is made with bearing faces formed in the shape of spherical
concave zones surrounding the inlet and outlet thereof and applied to
short tubes or collars having correspondingly formed surfaces, which

page_text: clamped centrally by any known
holding them to their seats on the
pipe, and forming a conveniently
short tubes or collars are in turn applied to suitable spherical seats
surrounding the apertures in the tanks, in the feed pipes, and in the
steam drum. This return bend is
means against the short tubes, thus
tanks, and steam drum, and feed
applied and cheap fluid connection of sufficient flexibility to avoid
strain from expansion and contraction of the various parts of the
generator. When used for purposes of navigation I set these boilers in
furnaces formed of vertical staves tongued and grooved together and
made hollow to contain water, these staves are put in fluid communica-
tion with a feed or supply pipe and the tanks of the steam generator by
means of the connecting picces or return bends and short spherical faced
tubes such as herein-before described, applied at the upper and lower
ends of the staves. A vertical partition extending nearly to the top
and bottom in the cavity of each of the staves serves to divide and
separate the ascending and descending currents produced by heating the
water therein. By making these staves of small cross sectional area risk
of disastrous explosion is avoided, and by grooving and tongucing them
together sufficient play is afforded to avoid any straining from expansion
and contraction without a possibility of flame passing the interstices
between the staves.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 27th June 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Southampton
Buildings, London, Patent Agents, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of December, in the
year of our Lord One thousand eight hundred and seventy, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Robert Lake, Her special
licence that I, the said William Robert Lake, my executors, adminis-
trators, and assigns, or such others as I, the said William Robert
Lake, my executors, administrators, and assigns, should at any time

page_text: "
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN STEAM GENERATORS, AND IN FURNACES THEREFOR," a com-
munication to me from abroad by S. Lloyd Wiegand, of Philadelphia,
Pennsylvania, United States of America, upon the condition (amongst
others) that I, the said William Robert Lake, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, 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 Robert Lake, 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, reference being had to the accompanying
Drawing forming a part of this Specification.
This Invention consists in forming the upper vessels of steam boilers,
the heating surfaces of which are composed of tubes suspended in a
furnace, in compartments so arranged as to produce an active circulation
of the water therein contained, and to facilitate the separation of the
steam from the water by means of deflectors, and of such small area
of cross section as entirely to obviate all possibility of destructive
explosion, and at the same time afford more uniform distribution of the
draft on all parts of the grate, making the upper vessels in the small or
portable sizes in folds or coils, and in the larger sizes in separate sections,
united by an improved connecting or coupling device; and in an
improved cap or lower termination of the suspended tubes, which tubes
are so disposed or arranged as to be effectively presented to the action
of the flames and gases rising in the furnace. Also in a furnace formed
of separate sections, specially adapted to the use of this boiler when
applied to marine and inland navigation uses and in locomotives.
DESCRIPTION OF THE DRAWING.

page_text: Figure 3 shows a plan of the same; Figure 4 shows a longitudinal
section in a vertical plane of one of the sections of the same.
Figure 5 shows an end elevation of one of the sections; Figure 6
shows one of the tubes thereof, drawn in vertical section on an enlarged
scale.
Figures 7 to 16 inclusive show plans, elevation, and a section of
several forms of cap for the lower ends of the tubes.
Figure 17 shows a portion of a tube closed, with its own material
in a form similar to the cap.
Figures 18, 18, 18, and 18°, show front elevations of different forms
of the connecting or coupling device; Figures 19, 19, 19, and 19°,
show sections and elevations thereof; Figure 20 shews a plan of a
modification of the same for uniting three vessels; Figure 21 shews
in plan an application of this last modification; Figure 22 shews an
application of the same in vertical section.
Figure 23 shows in elevation at the left side an application of the
modification shewn in Figure 19, and at the right side an application of
the form shewn in Figure 18.
Figure 24 shews the modification illustrated in Figure 20 in front
clevation as applied to an inclined tube boiler.
Figure 25 shews a bolt for securing the connection in position;
Figure 26 shows a short tube or collar, used with and peculiar to this
connection.
Figure 27 shews a spring washer used sometimes on the bolt to hold
the connection in place.
Figure 28 shews a plan of the upper vessel of one of these boilers
made for portable use; Figure 29 shews a vertical section thereof.
Figure 30 shews a portable boiler in clevation, having the right half
drawn in section.
Figures 31 to 36 inclusive show plans of modified forms of upper vessels
or tanks for portable boilers.
Figure 37 shows a side elevation of a boiler with the sectional furnace
adapted to marine purposes; Figure 38 shows a front elevation of the
same, with the right half drawn in section.

page_text: Figure 39 shews a plan of a sectional furnace without the boiler,
and exhibits the manner in which the several sections are jointed
together.
Figure 40 shows one of the sections of the furnace wall in front
elevation, with the internal form drawn in dotted lines; Figure 41 shows
a horizontal section of the same.
Figure 42 shows a horizontal section of one of the sections forming
the corner of the furnace; and Figures 43 to 46 show in horizontal
section several modifications of guides marked N in the tubes B.
A in Figures 1, 2, 3, 4, and 5 represents tanks, from which tubes B
are suspended in the furnace C. The grates D of the furnace may bo
made of any known forms, as may also the feeding or firing doors E and
ash-pit F. The tanks A are formed in three compartments; G, being
the lowest H, the middle; and I, the upper compartment. The com-
partment G communicates with the compartment H at K, see Figures 2
and 4. The compartment H communicates with the compartment I
by means of the necks L, shewn in Figures 2 and 4. In the upper
chamber I, I sometimes place oblique deflecting pieces marked Z, in
Figure 4, which when the boiler or steam gencrator is partly filled with
water and heat is applied, serve to facilitate the separation of the steam
from the water, which boils up through the necks L to the left from the
compartments G at K, as shewn in Figure 4. The deflecting pieces Z
also perform another function in bracing the sides of the chamber I,
thus imparting greater lateral strength to said chamber. The partition M
separating the compartments G and H is perforated concentrically with
the axes of the tubes B, and a flow of water downward is permitted
through the perforations in the partition plate M, into the tubes or
guides M, as shewn in Figure 4. The guides N extend nearly to the
bottom of the tubes B.
It will be seen upon inspection of Figure 1 that the tanks A are not
so wide at the lower part as at the upper part, and spaces marked 2,
arc left between them. These spaces perform the function of flues
in carying off the gaseous products of combustion upward from the
furnace, and communicate with the horizontal flues marked 3, between
the necks L, and thence the gases pass to the chimney by the side,
flues marked 4. By dividing the draft into numerous flues in this
manner a more uniform combustion is maintained on all parts of the
grate. The feed water is supplied to the chamber H, through the neck

page_text: or aperture O, shewn in Figures 2 and 4, by means of a peculiar con-
necting device P, herein-after described, from the feed pipe Q. Steam
is delivered from compartment I through the neck R, best seen in
Figure 4, and by means of the several peculiar connecting pieces S (similar
to the connections P, and herein-after described) shewn in Figures 1, 2,
and 5, is collected into the steam drum or steam pipe T, represented in
Figures 1, 2, and 3. The lower end or termination of the tube, which
may be closed either with its own material or a cap screwed thereon, is
so shaped as to form conical shoulders U, which support the tubes or
guides N centrally in the tubes B, and have a channel or channels V
extending from the bottom of the tube or cap for leading up to the
annular space surrounding the guide N, so as to provide a sufficient
course or conduct for the return of the water which, as will be herein-
after explained, descends from the chamber H through the central
channel of the guides N and rises again in the tubes B to the chamber G
of the tank whenever the generator is supplied with water and heat
generated in the furnace. The mode of circulation in the tank may be
in a direction transverse to the tanks instead of lengthwise with them
by having a guide or plate made in the shape indicated by the dotted
lines M', M', in Figure 5. The circulation in the tank will take place
in the direction of the dotted arrows. The guide plate M¹ forms a trough
in the centre of the tank A, into which the feed water first passes and
by reason of its greater specific gravity remains in it until it passes
down the channel W in the tube B. If the tubes B are so placed in
rows, as shown in Figures 1 and 5, that each alternate space between the
rows is narrow and the other alternate spaces are wide, and have flues
over them between the tanks, and if the tubes are not too long a flat
guide dividing the tubes B into two chambers prevents the current
descending through the trough M', and the channel W from being
interfered with by the rising current in the channel Y¹, which
passes up into the tank between the guides M¹ and the side of the
tank A

page_text: Figure 15 shews an clevation of Figure 9, having the channels V
formed in helices, like the twist of an auger or the threads of a two
threaded screw. Figure 16 shews a vertical section of the cap repre-
sented in plan view in Figure 7. Figure 17 shews in clevation the
lower portions of one of the tubes B, in Figures 1 and 2, closed by its
own material in the same form as the bottom of the cap represented
in Figures 7 and 8. Figuro 6 shews in section a tube B, provided with
a guide N', formed differently from those shewn in the other Figures.
This guide N is in form like the spiral shavings produced from
iron or steel by the side cutting tool of a machinist's engine latho
during the operation of turning the outer surface of a cylinder.
Through the guide N¹ there is a central channel W leading from
one end to the other within the coils or helices in the direction of
the axis. There is a spiral space or opening X extending the entire
length of the guide N¹ and affording a fluid communication from
the channel W to the spiral channel Y formed between the coils
or helices of the guide N¹ and the internal surface of the tube B.
When water flows into the upper end of the guide N¹ it flows directly
down the channel W, and when the tube B is filled with water upon
the application of heat the water in contact with the tube B becomes
lighter than that in the channel W and the water in the spiral channel
Y rises in a spiral direction whilst the water in the channel W descends
in the direction of the channel W. In the event of the water supply to
the top of the guide being suspended the water from the channel Y can
pass into the channel W near the water level through the space X,
whereas in the case of a cylindric tubular guide being used the cir-
culation of water ceases so soon as the supply of water to the top of the
guide tube N fails, and in case the tubes B arc of small diameter the
water contained in them is forcibly ejected by the steam formed in the
lower portion thereof.
An advantage is believed to be derived from the rotating or spiral
motion of the water in the tubes B by reason of the water being heavier
than the steam. During the generation of steam it is by reason of its
greater centrifugal force kept in more intimate contact with the tubes B
than if it moved in lines parallel with the axis of the tubes. The greater
cost of the guides N' is an impediment to their use instead of the cylindrical
tube guide N. Various other modifications in form of the inside tube or
guide may be used, varying from a cylindrical tube to crescent or prismatic

page_text: shaped segments of cylindric prisms as shewn in Figures 43-45. In all
of them the current receiving the least heat descends, whilst that receiving
the greater rises.
Figure 18 shows in front elevation the connecting device P by which
the necks O of the tanks A are brought into fluid communication with
the feed pipe Q. The connections S by which the tanks A are attached
to the steam drum T are similar in construction to the connections P,
and a description of the connections P will therefore suffice for both.
This connection consists of a hollow body or return bend a shewn in
front view in Figure 18, and in section in Figure 19. The outlets of
the bollow return bend are circular and have the bearing surfaces around
the outlets, formed in the shape of concave spherical zones. The vessels,
tanks, or pipes, a portion of which are shewn and marked band in
Figure 19 have similar apertures and bearing faces. Between the
spherical bearing faces of the return bend a, and the bearing faces of
the vessels band 6' in Figure 19 are placed short tubes c shewn with
the right half in section in Figure 26, the ends of which are convex
spherical zones, the radii of which are indicated by dotted lines in
Figure 26. Between the return bend a and the short tubes c and
between the tubes c and vessels band b¹ gaskets of gum or cloth or
soft metal may be placed, or they may be brought together with direct
contact of the collars c with the return bend a and the vessels band ',
it has been found in practice to be most convenient to us gaskets of
gum cloth in these joints. These joints thus described with spherical
bearing faces permit of a sufficient degree of flexibility to avoid the
strains ordinarily incident to the unequal expansion of parts from
variations of temperature. The return bend a is held in position by a
bolt d and nut e shewn in Figure 19. The bolt passing through a
central hole shewn in Figure 18, which hole f being surrounded by a
tube formed in the metal of the return bend divides the fluid channel in
the return bend a.
In Figures 18 and 19ª is shewn a return bend in which the fluid
channel is entirely on one side of the bolt hole f. The elasticity of this
connection may be further increased by using a bolt bend as shown in
Figure 25, so as to impart elasticity thereto or by using a spring washer
as shewn in Figure 27 under either the head or nut of the bolt.
In Figures 18 and 19° is shown a mode of securing a return bend
in position by means of two bolts and cross bar and clamp h. In

page_text: Figures 18 and 19 the return bend a is shewn secured by a strap
clamp i with a set screw k.
In all these modifications the spherical faced short tubes or collars c,
arc employed and form a characteristic feature thereof. Figure 20
shews a return bend having three outlets instead of two; Figure 21
shews a plan of the same as applied to a vertical sectional boiler; and
Figure 22 shews an application thereof in vertical section, an inspection
of which Figures in connection with the description already recited
will sufficiently explain the mode of construction and use; Figure 23
shows in sectional side elevation an application of this connection to a
sectional boiler formed with inclined tubes, the front or upper con-
nections thereof are made with the return bends having three outlets
(as more clearly shewn in Figure 24, which is a front view of Figure 23)
and the back or lower connections having two outlets.
Figures 37 and 38. exemplify the application of this connection with
two outlets to a sectional furnace (formed of staves in a manner herein-
after explained) which is useful in adapting this and other forms of
boiler to purposes of marine and river navigation, and to locomotive
use. Figure 38 shews a front elevation of the sectional furnace adapted
to purposes of navigation, the right half being drawn in section. This
furnace is made of parallel vertical staves with suitable rectangular
pipes m forming the case, and a rectangular pipe n forming the lintel
of the fire door. Figure 37 shews a side elevation of the same. Figure
39 shews a horizontal view thereof in the plane of the dotted horizontal
line in Figure 38, the boiler or generator being removed. Figure 40
shews a stave separately with the internal form drawn in dotted lines.
Figure 41 shews a horizontal section of one of the staves 1, and Figure 42
a horizontal section of one of the corner staves F.
Upon inspection of Figures 39, 41, and 42, it will be seen that tho
staves are tongued and grooved together, the corner staves / differing
from the staves which form the front sides and back of the furnace
in having the tongue o on the side of the stave at right angles to the
groove p instead of being on the side opposite to the groove. Each of
the staves and is hollow, and formed in two parallel upright com-
partments which intercommunicate at the top and bottom. One of
theso compartments is in the tongue o, the other marked q is in the
body of the stave. When these staves are arranged together to form

page_text: the furnace it will be scen upon reference to Figure 39 that the heat
of the furnace acts directly on the bodies of the said staves 1, and
that the tongues being in the grooves p are not exposed to the same
temperature. The effect of this difference of temperature is to cause
the water in the compartment q in the body of the stave to rise and be
replaced by the water flowing in at the lower end from the compartment
in the tongues o, which compartment in o receives a supply of water
at the upper end from the compartment q; a continuous circulation is
thus maintained therein so long as heat is applied. The several staves /
and forming the wall of the furnace are put in fluid communication
with the pipes m and n at the lower end with the tanks A, at the upper
ends by means of the connecting devices shewn in Figures 18 and 19.
Water is in this way supplied to the tanks A, and any steam that is
generated in the staves / rise into the tanks whence it passes through
the connections P to the steam drum T together with the steam
generated in the tubes B hanging in the furnace C. It is expedient in
connecting the tanks of sectional steam generators with the steam
drums thereof to introduce the steam above the bottom of the drum,
and to provide a return pipe S leading from the bottom of the steam
drum T to the feed pipe Q as shewn in Figure 1, or into the pipe mas
shewn in Figures 37 and 38. This pipe S permits the return to the
lower part of the boiler of any water that may be carried up mechanically
with the steam into the steam drum and avoids the annoyance known
to steam engineers as priming. The boilers or steam generators already
described are of what is known as the sectional varicty, that is to say,
they are composed of several separable sections, and boilers of largo
power are obtained by collecting the steam from a number of such
sections. The advantages realized by this system of construction is that
vessels of small area of cross section can be employed throughout such
structures, and since the disastrous damage produced by destructive;
explosion is the result of the reaction of fluid pressure in vessels of large
cross sectional area being suddenly liberated by the rupture of such
vessels destructive explosion of such sectional boilers is impossible;
besides which in vessels of small cross sectional area much less material
is requisite to produce the same strength to resist internal pressure than
in large vessels of the same superficies. The extent of surface exposed
to the action of heat being the chief exponent of the steam generating
capacity of the boiler large power is thus attainable without risk of

page_text: disastrous explosion. In making small steam generators of a portable
character it is desirable to avoid the trouble and expense of having
many joints, so far as is possible, and yet at the same time to retain the
advantage of safety from destructive explosion. Portable forms of this
steam generator embodying these advantages are shewn in Figures 28,
29, 30, 31, 32, 33, 34, 35, and 36. The tank A in this form of generator
is made of small cross sectional area and the requisite size is obtained
by making it large in the direction of its length. To adapt it to
conveniently shaped furnaces it is formed in coils or folds which may
be of various forms. In the plan shewn in Figure 31 it is in the form
of an involute. In the plan shewn in Figure 32 it is made in parallel
folds. In Figure 33 it is shewn as a rectangular coil. In Figures 34
and 35 it is formed in curved segments t, t, t, united with a central
body u by bent radiating arms v, v, v. In Figure 36 the tank is shewn
as formed in the shape of a ring w united with a central body u by the
bent radiating arms v, v, v. In Figure 28 is shewn in plan view a form
of tank made with an external ring w united by the arm x to a smaller
ring w¹, and having a central body u united by the arm x¹ to the ring w¹.
Partitions shown in dotted lines, and marked 5 and 5¹, serve to form the
chambers G, H, and I, in the rings wo and w¹, necks x and x¹, and body
π into continuous channels, the utility of which arrangement will fully
appear when the mode of operating or using this Invention is herein-after
described. A vertical section of this last described plan of tank is
shown in Figure 29.
Figure 30 represents an elevation with the right half drawn in section
of a portable steam generator, the tank A being formed as shown in
Figures 28 and 29.
In Figure 30 the tubes B are shown suspended in the furnace C
above the grates D and ash-pit F, also the guides N, which reach from
the bottom of the chamber H nearly to the bottom of the tubes B. The
feed water is introduced at the lower part of the compartment H, and
the steam is drawn from the highest point in the compartment I at
the point marked y in Figure 28. The feed water introduced at this
point flows in the direction of the arrows in the compartment H, as
do also the currents of mingled steam and water rising from the tubes
B into the compartments G until they reach the openings K, K', in
the partition separating the compartments G and H, and H and I.

page_text: Upon reaching the compartment I the current flows in an opposite
direction to that indicated by the arrows, thus reaching the steam
outlet. In passing thereto through the chamber I the steam and
water separate from each other. Between the folds or coils of the
tank A are narrow flues marked 2 in Figures 28, 29, 30, 31, 32, 33,
34, 35, and 36. The function of these flues is to afford escape for the
gaseous products of combustion from the furnace C, and at the same
impart heat therefrom to the tanks A. In Figure 30 the tubes B
are inclined with the lower ends towards the flues 2, the result
of this arrangement is to present them more effectually to the action
of the fire in the furnace C by intercepting gaseous products
passing into the flues 2. In the portable boilers with the tanks
formed in coils or folds as described the connections or joints
necessary in sectional boilers are dispensed with, whilst the feature
of safety resulting from the small sectional area of the vessels is
retained. There are positions where from the limited height of space
at command it is inconvenient to use tanks having three compart-
ments, in such case, or when it is unimportant to separate the water
completely from the steam, as in heating apartments by steam of
low pressure, the upper compartment I may be dispensed with.
Having thus fully described the said Invention, as communicated
to me by my foreign correspondent, I claim,-
First. The system of forming tanks in compartments, so that the
circulation of water from the tubes produces a circulation in the
tank.
Second. Introducing the feed water at such a point that it readily
enters the descending currents in the tubes before coming in contact
with the rising current from the tubes B.
Third. The cap for closing the lower ends of the tubes with boshes
and channels as described.
Fourth. Dividing the draft into numerous flues betweens the tanks
as described.
Fifth. The flexible connection as described having the short spherical
faced tubes combined therewith.

page_text: Sixth. The sectional furnace formed of staves as described.
Seventh. The tanks for portable use made in folds or coils.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Twenty-fourth day of June, in
the year of our Lord One thousand eight hundred and seventy-
one.
Witness,
W. J. LOWE.
WILLIAM ROBERT LAKE. (L.S.)