IMPROVEMENTS IN STEAM GENERATORS STEAM GENE- RATORS
Year: 1865

page_text: LETTERS PATENT to John Lake, of Devonport, in the County of Devon,
Miller, for the Invention of "IMPROVEMENTS IN STEAM GENERATORS."
Sealed the 4th August 1865, and dated the 7th February 1865.
PROVISIONAL SPECIFICATION left by the said John Lake at the
Office of the Commissioners of Patents, with his Petition, on the 7th
February 1865.
I, JOHN LAKE, of Devonport, in the County of Devon, Miller, do hereby
5.declare the nature of the said Invention for "IMPROVEMENTS IN STEAM GENE-
RATORS," to be as follows, that is to say :-
This Invention relates to. a peculiar construction and arrangement of
internal flue steam generators or boilers for stationary engines whereby a
larger heating surface is obtained with a given size of boiler than can be
obtained in boilers of this class of the ordinary construction.
According to this Invention it is proposed to employ two, three, or more
internal flues, according to the size of boiler required, extending from the

page_text: front to the back end thereof. These internal flues are fitted at their front
ends into a flue plate, which forms the back of the furnace, such furnace or
fire-place is made to communicate direct with and is common to the whole of
the flues in lieu of having separate fire-places in the flues themselves. The
furnace or fire-place is surrounded at the sides and back by a water space
which communicates freely with the main body or barrel of the boiler. In
order to facilitate the cleaning of the flues a hinged door is fitted to the front
of the furnace opposite the entrances to such flues, and beneath this door is
hinged the fire door of the furnace. The internal flues are each provided at
their rear ends with a regulating throttle valve or damper, which may be
worked either together or separately, as required, from the front of the boiler,
the object of such valves or dampers being to confine more or less the hot
air and gases inside the internal flues in place of permitting them to pass off
with the draught freely into the chimney. A damper is also fitted at the
entrance to the flue of the chimney in order to regulate the general draught
from the external flues of the boiler.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Lake in the Great Seal Patent Office on the 7th
August 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN LAKE,
of Devonport, in the County of Devon, Miller, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of February, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Lake, Her special licence that I, the said John Lake,
my executors, administrators, and assigns, or such others as I, the said John
Lake, 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 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," upon the condition (amongst others) that I, the said
John Lake, by an instrument in writing under my hand and seal, should
particularly describe and ascertain the nature of the said Invention, and in

page_text: 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 John Lake, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement (to be as follows), that is to say:-
This Invention relates to a peculiar construction and arrangement of
internal flue steam generators or boilers for stationary engines whereby a
larger heating surface is obtained with a given size of boiler than can be
obtained in boilers of this class of the ordinary construction. According to
this Invention it is proposed to employ two, three, or more internal flues,,
according to the size of the boiler required, the said flues extending from the
front to the back end thereof, these internal flues are fitted at their front ends:
into a flue plate which forms the back of the furnace; such furnace or fire-
place is made to communicate direct with and is common to the whole of the
flues, in lieu of having separate fire-places in the flues themselves; the furnace
or fire-place is surrounded at the sides and back by a water space which com--
municates freely with the main body of the boiler. In order to facilitate the
cleaning of the flues a hinged or other door or covering is fitted to the front:
of the furnace opposite to the entrance to such flues, and beneath this door is
hinged or otherwise attached the fire door of the furnace. The internal flues
are each provided at their rear or back ends with a regulating throttle or other
valve, or damper, which may be worked either together or separately, as
required, from the front of the boiler, the object of such valves or dampers
being to confine more or less the hot air and gases inside the internal flues in
the place of permitting them to pass off with the draught freely into the
chimney. A damper is also fitted at the entrance to the flue of the chimney
in order to regulate the general draught from the internal flues of the boiler.
But in order that the true character, extent, and importance of my Invention
may be fully comprehended I will proceed to describe the Drawings hereunto
annexed, that is to say, Figure 1 represents a boiler or steam generator con-
structed according to my improvements, the steam chest A being applied or
omitted as desired or preferred. A part of the rear end of the boiler is repre-
sented in section for the purpose of exhibiting the flueways, two only being
visible in this view marked B and C, and this end of the generator. I have for
convenience represented abutting in and built up with the base of the stack D,
the lower portion of which is sbewn in section for the purpose of exhibiting the
valves and means of actuating the same hereafter to be referred to, as well as

page_text: the opening E, which may be temporarily bricked up or removed for a man
to enter to clean out the refuse or fine ashes that will accumulate at this
part from the cleaning out of the flues, also to be hereafter referred to. Not-
withstanding that I have exhibited the stack in immediate connection with
the rear end of the boiler or generator, but a flueway might be here formed
and carried away to be connected with the stack, which may be placed in any
convenient proximity to such generator and flueway. In such flueway or
stack I purpose applying any simple construction of damper, valve, or other
equivalent means by which I may be enabled to arrest, throttle, or prevent the
rapid flow of the heated air and gases that are constantly evolved from the
combustion of the fuel in the furnace, and escaping through the flueways of
the generator to the stack. As I desire to economise the heated air or flame
thus generated to its fullest extent for generating steam, I have not
thought it necessary to exhibit such damper or valve in the stack, as the same
may be variously constructed and applied according to the taste and judgement
of the engineer or user of such generator. The front part of my boiler or
generator is also exhibited in section for the purpose of shewing the manner
in which I purpose applying and incorporating the fire-box or furnace with
such boilers or generators. In which case a hollow space for holding water
and steam extends on each side and top of such furnace immediately in con-
nection with what may be termed the boiler proper, the back of the furnace
forming the end of such boiler, and through which the flueways B, C, as
well as the two others cut away to shew the interior, and thereby not seen in
this view are placed. The water or steam space at the top is marked F, while
the part at the bottom which extends from side to side is marked G, and
which part forms a base which rests on brickwork or other equivalent means
for supporting the front end of the generator. In this view I have exhibited
a coating of brickwork, shewn generally in section, and which brickwork sur-
rounds and extends up the sides and top immediately in front of the furnace
for receiving an iron plate marked H, H, and which plate is cast with a con-
tinuous flange I on the sides and top, which not only supports the brickwork
but adds strength and durability to this part, in which a portable door or
other covering hereafter to be referred to is applied, which may be connected
by suitable straps to the lugs and axis marked a, a, here shewn, or other
suitable means, and in which plate or cover another ordinary door is fitted,
either by a hinge joint, pendalum motion, or counterpoised as may be pre-
ferred, and through which door the fuel may be applied, but which door is
not exhibited in this view; b is the dead plate built into the brickwork on
each side, or otherwise secured, and for convenience forms a rest for the front

page_text: end of the fire-bars marked C, which rest at the back end on a cast-iron
support marked d, also taking a bearing on the brickwork each side of the
fire-hole marked e, and which cast-iron support I prefer casting with openings
for the air to readily pass off and act between and about the far end of the
fire-bars. Independent of the boiler or generator resting at the front on the
brick work as here shewn, I also adopt three saddles, more or less, as here
exhibited marked J, K, and L, which may be of cast iron, taking the curve
of the generator, but flat at the base to rest on the wood or other suitable
sleeper marked g, 9, 9, and which sleeper or sleepers may rest on masonry or
other equivalent means not liable to be depressed with the weight of the
boiler.
Fig. 2 is a transverse section of the last figure taken through the dotted
lines M, M, shewing the fire-bars in section and the means of supporting
them at the back by the part d; in this view the full form of the furnace is
shewn surrounded by a hollow water and steam way marked G, G, and F, and
in which view I have exhibited the four circular flueways marked respec-
tively B, C, and B', and C'.
Fig. 8 is a top view of Figure 1 looking down on the steam chest of the
generator, and representing the stack in section, as also a top view of the
escape ends of the two uppermost flueways marked B and B', likewise of one
portion of the brickwork surrounding the furnace and top edge of the plate
H, which is partly shewn in dotted lines. I have omitted the brickwork for
the purpose of shewing that it is not essential to my Invention that any
brick work should be used, notwithstanding I think it would be advantageous
to the extent here shown; and I will observe that if so preferred the fire-
box or furnace may be constructed of sufficient size and capacity to admit of
being lined with fire-brick, arranging such that the orifices or openings in
front of the flueways may be well preserved, and again in case that the brick-
work is omitted as here exhibited for surrounding the fire-box or furnace, the
plate H may be cast or otherwise formed of sufficient size as to encompass
the whole front of the fire-box, and to be provided with a flange or other
suitable equivalent means for overlapping the edge, so that a secure joint may
be formed with fire-clay, or other suitable materials, to exclude the air; in
that case it may be essential to cover the fire-box as well as the whole
exterior of the boiler or generator with a sufficient covering of felt or other
suitable covering, as exhibited in section at t, t, Fig. 1.
Fig. 4 simply represents a front view of Figure 3, with the plate H,
portable door N, and feeding door O represented partly broken off to shew
the interior of the fire-box, and which parts are omitted from Figure 1, to

page_text: which I will again refer for the purpose of describing the valves at the rear
end of the flues B and B', and C and C', which are represented in an end
view of the boiler or generator at Figure 5, marked with the same letters.
h and i are cones, which I prefer making of fire-clay, rather regular on the
surface, as exhibited at Fig. 6, or corrugated as at Fig. 7; the one permits of
the flueway being completely stopped, while the other retains openings around
the cones to the extent of the depth or number of the corrugations.
I do not purpose limiting myself to the use of four flueways as here shewn,
but in cases where four are used I prefer connecting and operating them as
here shewn, that is to say, the cone marked h and its corresponding one in
connection with it marked h¹ are attached to levers j, and which levers are
attached to an axis shewn in dotted lines marked k, and which said levers are
united together by a stretcher at 1, to which a chain is attached, which works
over a pulley marked m, supported on a suitable carriage as here shewn or
otherwise, and which chain passes through a small iron tube built in the stack
or other brickwork, and may be supported on another pulley fastened on the
side of the steam chest marked n, and from there it may pass over another
pulley or quadrant of sufficient area as to comprehend the range of its action,
and which quadrant may be fastened with a lever handle on the side of the
furnace or fire-box, so that by relieving the quadrant or chain the top valves
hand h¹, with their attending parts that support them, will fall down into a
pendant position with the axis k, thus shewing that the top flueway may be
wholly or partially opened or closed at the entire will of the engineer, and in
like manner so also may the valves i and i¹ be operated from their being
connected to an iron frame and axis at p, and having the weight q, if necessary,
attached to the lever r, to the end of which a chain shown by broken line
is attached working over a corresponding pulley to m, and working through a
corresponding tube in the stack, and over a pulley fastened to the reverse
side of the steam chest, and to corresponding appliances on the right-hand
side of the furnace, that the engineer may in like manner regulate the flow-
way of the lower flues C and C¹; and inasmuch as the object of my Invention
is to obtain the full heating effect arising from the increased surface afforded
by the flueways I employ, it will be obvious that such additional heating
surface cannot be calculated on unless the flueways are kept free from any
deposit of fine ashes as carried into them by the draft or suction of the stack
from the fire, and it is to provide for this great desideratum that the portable
extended door marked N, exhibited in Fig. 4, is rendered necessary, as by its
opening or removal from the front of the fire-box or furnace, and the
slackening of the chains so as to allow the conical valves to fall down, the

page_text: flues from end to end will be exposed, so that the engineer may apply or pass
a brush or other convenient appliances right through them as often as
necessary for thorough cleansing, and which I recommend, in order to fully
obtain the object herein-before stated, to be repeated daily or as frequently
as there should be any serious deposit in the flues. Not that I purpose con-
fining myself to the description of valves here shown, or to the means of
actuating them, as an ordinary throttle valve may be applied to a bar
working transversely or otherwise across the flueway on suitable axes, as
exhibited at Fig. 8, and to which a rod may be attached, by which such
throttle valves may be adjusted at right or any intermediate angle to arrest
the too rapid flow of the flame, heated gases, or heated air generated in the
furnace and flying through such flues to the stack, as it is by this means of
retaining and exhausting the heat generated that I am enabled not only to
equalize through the day the pressure of the steam generated, but also to
generate that steam by a very considerable diminution of fuel as ordinarily
consumed in obtaining and maintaining a certain pressure of steam according
to the size and capacity of the generator or boiler. Nor do I purpose con-
fining myself to the position as herein described of the means for controlling
such valves, as the same may be otherwise contrived than herein described and
exhibited, as I may actuate them immediately at the rear end of the boiler,
flueway, or base of the stack or otherwise as most convenient; and, again, if
throttle valves be used as exhibited at Figure 8, they may be perforated with
small holes as at S, which may be beneficial in not only retarding but sepa-
rating the current of heat, and which may be found beneficial in some
instances, and will in reality have the same effect as the corrugated cone
referred to in Figure 7.
Having thus given a general description of my Invention, and the manner
in which the same may be carried into effect to suit the convenience of
position, locality, or other requirement, I wish it understood that I do not
claim as of my Invention the constructing of steam boilers or generators with
flues, as that of itself is old; but what I claim and wish to protect under these
my in part recited Letters Patent is, the use of any desirable number of flues,
such flues being supplied with valves at or near the inner or rear end, such
valves being acted on individually, collectively, or otherwise for the purpose
of preventing the too rapid escape of the heat generated in the furnace, and
passing through such flues as herein-before stated, and by which means of
generating steam for fixed engines the necessity for external flues, brick
setting, or other cumbersome masonry is rendered entirely unnecessary, as
such masonry not only absorbs heat and acts injuriously on the surface of the

page_text: boiler with which it is in contact, but from the inconvenience of cleaning
renders the flueways more or less foul, and thereby contracts the heating
surfaces of such flues.
In witness whereof, I, the said John Lake, have hereunto set my hand
and seal, this Fourth day of August, in the year of our Lord One
thousand eight hundred and sixty-five.
Witness,
WILLIAM LOACH,
. Clerk to James S. Cockings,
Patent Agent,
Birmingham.
JOHN LAKE. (L.S.)*´¨

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN LAKE,
of Devonport, in the County of Devon, Miller, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain and Ireland, bearing
date at Westminster, the Seventh day of February, in the year of our
Lord One thousand eight hundred and sixty-five, in the twenty-eighth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said John Lake, Her special license that I, the said
John Lake, my executors, administrators, and assigns, or such others as
I, the said John Lake, 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 Isle of Man, an Invention of "IMPROVEMENTS IN STEAM
GENERATORS," for and during the term of fourteen years thence next
ensuing:

page_text: And whereas in pursuance and performance of a proviso in the said
Letters Patent contained, I, the said John Lake, did within six calendar
months next after the date of the said Letters Patent cause a Specifi-
cation in writing, under my hand and seal, particularly describing the
nature of the said Invention, and in what manner the same was to be
performed, to be duly filed in the Great Seal Patent Office:
And whereas since the filing of the said Specification I have been
advised that it covers or embraces certain forms of valves or dampers
which were not novel at the date of my said Letters Patent, I am there-
fore desirous of disclaiming all forms of valves or dampers other than
those of the conical form mentioned in the said Specification and illus-
trated by the Drawings thereunto annexed.
NOW KNOW YE, that I, the said John Lake, by and with the leave
of Her Majesty's Attorney-General, do hereby for the reason aforesaid,
and for effectuating the object aforesaid, strike out the words throttle
or other" occurring in page 3, line 23, of the Specification printed by
the Queen's. Printers, and published at the Great Seal Patent Office, and
I insert after the word "damper" in line 24, page 3, of the said printed
copy of the said Specification the words "such as is herein-after
described and illustrated by Figures 6 and 7 of my Drawings." I also
strike out that part of the said Specification which commences with the
words "not that" in page 7, line 5, and ends with the words "generator
or boiler" in line 17 on the same page. And in order to render the
.reading of the next paragraph more consistent I strike out the words
"nor do" which occur in the said line 17, page 7, and I insert the
words "do not "after the pronoun "I" in the same line and page. I
also strike out that part of the said printed copy of the said Specification
commencing with the words " and again if" occurring at line 21, page 7,
and ending with the words "referred to in Figure 7" in line 26 on the
same page. I further propose to alter the said Specification by inserting
after the words "neither do I claim the application generally of throttle
"valves, flap doors, or louvres to the inner or rear ends of the flues." I
also insert after the words "supplied with " in line 33, page 7, the words
"the herein-before described conical."
'
And in order that it may be clearly understood what is the Invention.
which I now consider to be secured by the herein-before in part recited
Letters Patent, I shall proceed to repeat (omitting preamble and testing

page_text: clause) my said Specification as proposed to be amended by this present
Disclaimer and Memorandum of Alteration, as follows:-
NOW KNOW YE, 'that I, said John 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 (to be as follows), that is to say: -
This Invention relates to a peculiar construction and arrangement of
internal flue steam generators or boilers for stationary engines, whereby
a larger heating surface is obtained with a given size of boiler than can.
be obtained in boilers of this class of the ordinary construction. According
to this Invention it is proposed to employ two, three, or more internal
flues, according to the size of the boiler required, the said flues ex-
tending from the front to the back end thereof. These internal flues are
fitted at their front ends into a flue plate, which forms the back of the
furnace. Such furnace or fire-place is made to communicate direct with
and is common to the whole of the flues in lieu of having separate fire-
places in the flues themselves. The furnace or fire-place is surrounded at
the sides and back by a water space, which communicates freely with
the main body of the boiler. In order to facilitate the cleaning of the
flues a hinged or other door or covering is fitted to the front of the
furnace opposite to the entrance to such flues, and beneath this door is
hinged or otherwise attached the fire-door of the furnace. The internal
flues are
cach
^
provided at their rear or back ends with a regulating valvo
or damper, such as is herein-after described, and illustrated by Figures 6
and 7 of my Drawings, which may be worked either together or sepa-
rately as required from the front of the boiler, the object of such valves
or dampers being to confine more or less the hot air and gases inside the
internal fues in the place of permitting them to pass off with the
draught freely into the chimney. A damper is also fitted at the entrance
to the flue of the chimney in order to regulate the general draught from
the internal flues of the boiler.
But in order that the true character, extent, and importance of my
Invention may be fully comprehended, I will proceed to describe the
Drawings hereunto annexed, that is to say:-
Figure 1 represents a boiler or steam generator constructed according
to my improvements, the steam chest A being applied or omitted as
desired or preferred. A part of the rear end of the boiler is represented

page_text: in section for the purpose of exhibiting the flueways, two only being
visible in this view, marked B and C; and this end of the generator I
have for convenience represented abutting in and built up with the base
of the stack D, the lower portion of which is shewn in section for the
purpose of exhibiting the valves and means of actuating the same
hereafter to be referred to, as well as the opening E, which may be
temporarily bricked up or removed for a man to enter to clean out the
refuse or fine ashes that will accumulate at this part from the cleaning
ut of the flues, also to be hereafter referred to. Notwithstanding
that I have exhibited the stack in immediate connection with the
rear end of the boiler or generator, but a flueway might be here
formed and carried away to be connected with the stack, which may
be placed in any convenient proximity to such generator and flueway.
In such flueway or stack I purpose applying any simple construction
of damper, valve, or other equivalent means by which I may be.enabled
to arrest, throttle, or prevent the rapid flow of the heated air and
gases that are constantly evolved from the combustion of the fuel in
the furnace, and escaping through the flueways of the generator to
the stack. As I desire to economise the heated air or flame thus
generated to its fullest extent for generating steam I have not thought
it necessary to exhibit such damper or valve in the stack, as the same
may be variously constructed and applied according to the taste and
judgment of the engineer or user of such generator.
The front part of my boiler or generator is also exhibited in section
for the purpose of shewing the manner in which I purpose applying and
incorporating the fire-box or furnace with such boilers or generators, in
which case a hollow space for holding water and steam extends on each
side and top of such furnace immediately in connection with what may
be termed the boiler proper, the back of the furnace forming the end of
such boiler, and through which the flueways B, C, as well as the two
others cut away to shew the interior, and thereby not seen in this view,
are placed. The water or steam space at the top is marked F, while the
part at the bottom, which extends from side to side is marked G, and
which part forms a base which rests on brickwork or other equivalent
means for supporting the front end of the generator. In this view I
have exhibited a a coating of brickwork, shewn generally in section, and
which brickwork surrounds and extends up the sides and top immediately
in front of the furnace for receiving an iron plate marked H, H, and

page_text: which plate is cast with a continuous flange I on the sides and top,
which not only supports the brickwork, but adds strength and durability
to this part, in which a portable door or other covering hereafter to be
referred to is applied, which may be connected by suitable straps to the
lugs and axis marked a, a, here shewn, or other suitable means, and in
which plate or cover another ordinary door is fitted, either by a hinge.
joint, pendulum motion, or counterpoised as may be preferred, and
through which door the fuel may be applied, but which door is not
exhibited in this view. b is the dead plate built into the brickwork on
each side or otherwise secured, and for convenience forms a rest for the
front end of the fire-bars marked C, which rest at the back end on a
cast-iron support marked d, also taking a bearing on the brickwork each
side of the fire-hole marked e, and which cast-iron support I prefer
casting with openings for the air to readily pass off, and act between
and about the far end of the fire-bars. Independent of the boiler or
generator resting at the front on the brickwork as here shewn, I also
adopt three saddles, more or less, as here exhibited marked J, K, and L,
which may be of cast iron, taking the curve of the generator, but flat at
the base to rest on the wood or other suitable sleeper marked 9, 9, 9, and
which sleeper or sleepers may rest on masonry or other equivalent
means not liable to be depressed with the weight of the boiler.
:
Figure 2 is a transverse section of the last Figure taken through the
dotted lines M, M, shewing the fire-bars in section, and the means of
supporting them at the back by the part d. In this view the full form of
the furnace is shown surrounded by a hollow water and steam way
marked G, G, and F, and in which view I have exhibited the four
circular flueways marked respectively B, C, and B¹ and C³.
Figure 3 is a top view of Figure 1, looking down on the steam chest
of the generator, and representing the stack in section, as also a top view
of the escape ends of the two uppermost flueways marked B and B',
likewise of one portion of the brickwork surrounding the furnace and
top edge of the plate H, which is partly shewn in dotted lines. I have
omitted the brickwork for the purpose of shewing that it is not essential
to my Invention that any brickwork should be used, notwithstanding I
think it would be advantageous to the extent here shewn; and I will
observe that if so preferred the fire-box or furnace may be constructed.
of sufficient size and capacity to admit of being lined with fire-brick,
arranging such that the orifices or openings in front of the flueways may

page_text: be well preserved; and again in case that the brickwork is omitted as here
exhibited for surrounding the fire-box or furnace, the plate H may
be
cast or otherwise formed of sufficient size as to encompass the whole
front of the fire-box, and to be provided with a flange or other suitable
equivalent means for overlapping the edge, so that a secure joint may be
formed with fire-clay or other suitable materials to exclude the air; in
that case it may be essential to cover the fire-box as well as the whole
exterior of the boiler or generator with a sufficient covering of felt or
other suitable covering as exhibited in section at t, t, Figure 1.
Figure 4 simply represents a front view of Figure 3, with the plate H,
portable door N, and feeding door O, represented partly broken off to
shew the interior of the fire-box, and which parts are omitted from
Figure 1, to which I will again réfer for the purpose of describing the
valves at the rear end of the flues B and B', and C and C¹, which are
represented in an end view of the boiler or generator at Figure 5, marked
with the same letters. and i are cones, which I prefer making of fire-
clay, rather regular on the surface, as exhibited at Figure 6, or corru-
gated as at Figure 7; the one permits of the flueway being completely
stopped, while the other retains openings around the cones to the extent
of the depth or number of the corrugations.
I do not purpose limiting myself to the use of four flueways, as here
shewn, but in cases where four are used I prefer connecting and ope-
rating them as here shewn, that is to say, the cone marked h and its
corresponding one in connection with it marked ¹ are attached to
levers j, and which lévers are attached to an axis, shewn in dotted lines,
marked k, and which said 'levers are united together by a stretcher at 7,
to which a chain is attached which works over a pulley marked m,
supported on a suitable carriage, as here shewn, or otherwise, and which
chain passes through a small iron tube built in the stack or other brick-
work, and may be supported on another pulley fastened on the side of
the steam chest marked n, and there it may pass over another pulley or
quadrant of sufficient area as to comprehend the range of its action, and
which quadrant may be fastened with a lever handle on the side of.the
furnace or fire-box, so that by relieving the quadrant or chain the top
valves h¹ and h¹, with their attending parts that support, them, will fall
down into a pendant position with the axis k, thus shewing that the top
flueway may be wholly or partially opened or closed at the entire will of
the engineer; and in like manner so also may the valve i and i be

page_text: operated from ther being connected to an iron frame and axis at p, and
having weight q, if necessary, attached to the lever r, to the end of
which a chain, shown by a broken line, is attached, working over a
corresponding pulley to m, and working through a corresponding tube in
the stack and over a pulley fastened to the reverse side of the steam
chest and to corresponding appliances on the right-hand side of the
furnace that the engineer may in like manner regulate the flowway of
the lower flues C and C₁; and inasmuch as the object of my Invention
is to obtain the full heating effect arising from the increased surface
afforded by the flueways I employ, it will be obvious that such additional
heating surface cannot be calculated on unless the flueways are kept free
from any deposit of fine ashes, as carried into them by the draft or
suction of the stack from fire, and it is to provide for this great desi-
deratum that the portable extended door marked N, exhibited in
Figure 4, is rendered necessary, as by its opening or removal from the
front of the fire-box or furnace, and the slackening of the chains so as
to allow the conical valves to fall down, the flues from end to end will
be exposed, so that the engineer may apply or pass a brush or other
convenient appliances right through them as often as necessary for
thorough cleansing, and which I recommend in order to fully obtain the
object herein-before stated, to be repeated daily or as frequently as there
should be any serious deposit in flues. I do not purpose confining
myself to the position as herein described of the means for controlling
such valves, as the same may be otherwise contrived than herein
described and exhibited, as I may actuate them immediately at the rear
end of the boiler flueway, or base of the stack, or otherwise as most
convenient.
the
Having thus given a general description of my Invention, and the
manner in which the same may be carried into effect to suit the con-
venience of position, locality, or other requirement, I wish it understood
that I do not claim as of my Invention the constructing of steam boilers
or generators with flues, as that of itself is old, neither do I claim the
application generally of throttle valves, flap doors, or louvres to the inner
or rear ends of the flues; but what I claim and wish to protect under
these my in part recited Letters Patent is, the use of any desirable
number of flues, such flues being supplied with the herein-before
described conical valves at or near the inner or rear end, such valves
being acted on individually, collectively, or otherwise, for the purpose

page_text: of preventing the two rapid escape of the heat generated in the furnace,
and passing through such flues as herein-before stated, and by which
means of generating steam for fixed engines the necessity for external
flues, brick setting, or other cumbersome masonry is rendered entirely
unnecessary, as such masonry not only absorbs heat and acts injuriously
on the surface of the boiler with which it is in contact, but from the
inconvenience of cleaning renders the flueway's more or less foul, and
thereby contracts the heating surfaces of such flues. .
In witness whereof, I, the said John Lake, have hereunto set my
hand and seal, this Twenty-first day of October, in the year of
our Lord One thousand eight hundred and seventy-two.
J. D. COLERIDGE,
25th Nov., 1872.
Attorney-General.