IMPROVEMENTS IN TREATING WOOD AND OTHER VEGETABLE FIBROUS MATERIALS FOR THE PRODUCTION OF PAPER PULP, AND IN THE BOILERS AND APPARATUS EMPLOYED THEREFOR
Year: 1869

page_text: LETTERS PATENT to George Sinclair, of the Town of Leith, in the
County of Edinburgh, North Britain, Boiler Maker, for the In-
vention of "IMPROVEMENTS IN TREATING WOOD AND OTHER VEGETABLE
FIBROUS MATERIALS FOR THE PRODUCTION OF PAPER PULP, AND IN THE BOILERS
AND APPARATUS EMPLOYED THEREFOR."
Sealed the 1st March 1870, and dated the 3rd November 1869.
PROVISIONAL SPECIFICATION left by the said George Sinclair at the
Office of the Commissioners of Patents, with his Petition, on the
3rd November 1869.
I, GRORGE SINCLAIR, of the Town of Leith, in the County of Edinburgh,
North Britain, Boiler Maker, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN TREATING WOOD AND OTHER VEGETABLE
FIBROUS MATERIALS FOR THE PRODUCTION OF PAPER PULP, AND IN THE BOILERS
AND APPARATUS EMPLOYED THEREFOR," to be as follows, that is to say :-
The said Invention consists mainly and substantially in the heating,
boiling, or first treating of the split wood, wood shavings, "esparto,"
and other vegetable fibrous materials mixed with the proper amount of

page_text: "
water and caustic soda or "lies usually employed, or for the kind and
quantity of fibrous materials being treated, in order to prepare them for
"paper pulp" or "fibre pulp" within new or improved constructions
and arrangements of close vessels or boilers, by the direct action or
radiation of the heat through the outer sides or shells of these boilers,
each of which boilers, under one modification or arrangement for the
said purpose of direct heating is placed within a confined heating walled
flue or chamber of brickwork, having the heated products of combustion
from the furnace passed into and through it, so as to act on the outer
surface of the boiler. Each of these new or improved "fibre pulp"
preparing boilers has an inner casing or vessel formed of thin sheet
metal, perforated closely with small holes, or formed of strong wire
cloth, in either case secured to the outer main close heating shell or
vessel by small short stays or studs, or it may be rings or longitudinal
feathers, at an inch or two off or from and all round the interior of the
heating vessel opposite to where the heat impinges or is imparted to it.
Thus the outer hot shell is prevented from touching, overheating, or
burning the fibrous materials which are all placed and kept within this
inner perforated vessel, and so allow the liquor or "lies" to circulate
freely up within the narrow space between the outer and inner vessel,
and through the perforations or openings into the inner vessel, and
through the body of the fibrous materials being treated or boiled and
reduced within it.
Under one arrangement it is desirable to have the boilers formed of a
long narrow shape, that is, by preference, a cylindrical, of such a diameter
that the contents would be easily heated from the outer circumference,
as stated (as, say, from about two to four feet in diameter, and from
three to six diameters in length), made of the best strong malleable iron
boiler plate, with conical or other equivalent strongly formed ends,
having at top and bottom respectively a large filling and a discharging
pipe or cylindrical door (by preference from eighteen to twenty inches in
diameter), with a strong lid or cover, easy of removal and attachment,
as by being screwed into the mouth or door like an ordinary water plug,
or the breech of a rifle with turned flanges, which might be secured by
bolts when desired, and made fluid pressure tight by fine grooves and
rings of copper wire, or other equivalent simple joint. The large filling
pipe or door is, by preference, made to project up through the brickwork
at top vertically for the convenience of filling the vessel, and the

page_text: discharge cylindrical door is placed horizontally out through the brick-
work at the extreme lower end of the vessel, for the more easy
withdrawal of the solid fibrous matters for subsequent treatment
laterally into other vessels, which may either be stationary or portable,
each of which may be carried on a carriage frame and wheels. A small
supply vessel (by preference of a spherical or cylindrical form) is placed
on the top and above the building and boiler, which are directly con-
nected at the very top of both by a small pipe, and by another small
pipe leading from the bottom of the supply vessel into a lower part of
the fibre preparing boiler, which is built vertically in the heating
chamber of brickwork with an annular flue heating space all round it,
either set on its lower strong end or hung by brackets to the brick wall
or building at the top. The flames and heated gases or products of
combustion from the fuel and furnace (which may be of any ordinary
construction) is, by preference, led into the bottom of the said annular
heating space between the boiler and brickwork, either directly or over
the top of or through oblong holes in a flame protecting wall interposed
between the main entrance or flue from the furnace and the lower part
of the boiler, to protect it from the injurious and excessive or intense
action of the entering volume of flame and gases, which after acting on
and heating the outer surface of the boiler either pass off at the top
through a flue or funnel on one or both sides, or at a lower part of the
heating flue, after passing over the dividing or flame bridge by a
suitable duct or flue, which as well as the funnels or flues at the top
may be led direct to an ordinary brick chimney, and either or both the
main entrance and exit flues to each heating chamber may be controlled
by "dampers."
The treating of the fibrous materials and action of the boiler containing
them and this arrangement of improved apparatus generally is as
follows: The entrance and charging cover on top of the boiler is
screwed off, and the wood shavings, "esparto," or other fibrous material
to be treated is put in, and retained within the inner thin perforated or
wire cloth vessel of the boiler with a sufficient charge of caustic soda,
and then filled up to the top with water in the usual proportions for this
part of the process, when the cover is then firmly screwed down, and

page_text: products of combustion passing over the flame bridge and round about
and between the outer heating shell of the boiler and the building up to
and out through the two funnels into the air or brick chimney, according
as arranged, all so as to boil the fibrous materials and alkaline liquors for
the required time and degree desired, after which the "lies" be
may
drawn off by a small blow-off pipe and cock for the purpose from the
bottom of the outer shell, when the lid on the large discharge duct may
be taken off, and the fibrous materials withdrawn from the inner per-
forated vessel; or otherwise both the "lies" and fibrous materials may
be withdrawn through the large discharge door, or, when the boiler is
intended for boiling the fibrous materials down into a pulp a long
blow-off pipe with cock (of a conveniently large size, as from five to ten
inches in diameter) is connected direct with the bottom of the boiler at
the one end, and a large cylindrical receiving vessel at the other, for the
subsequent reception and treatment of the pulp after every
"boiling
down" and discharge from the boiler.
Another arrangement consists in enclosing one, two, three, or four of
these new or improved duplex "fibre pulp" treating boilers within a close
outer cylindrical superheating steam vessel formed of strong boiler plate
iron placed vertically within an annular flue and flame heating chamber
of brickwork (analagous to that described in reference to the former
arrangement) of a single boiler placed in such a heating chamber.
Each
of the said duplex boilers (within the said steam heating boiler or vessel)
has a filling door and lid projecting up through the steam heating vessel
and brickwork for filling it, and has a long horizontal discharge pipe
and lid projecting out radially at and through the bottom of the steam
heating vessel and brickwork of the flue heating chamber for the
discharge of the treated materials in each. All the boilers are directly
connected to each other by small pipes at both the top and bottom
within the steam vessel, and connected to one small supply vessel above
for the whole, all so as to insure the whole of the boilers being full of
liquid, and working well under equal pressure, heat, and circulation of
the alkaline liquids, which may be drawn off from the whole at once
when the boiling or treatment of the fibrous materials is completed by
one blow-off pipe and cock; or otherwise both the liquor and fibrous
materials may be withdrawn from each vessel separately by its discharge
mouth and door, all as more fully described in reference to the former
modification. A small water pipe with stop-cock may be connected by

page_text: a branch or branches to the upper part of the outer shell of these boilers,
so as to wash the annular surface between the inner and outer shells
occasionally when desired after each or several discharges of the
materials. In this latter arrangement the heated products of com.
bustion from the furnace are first made to raise or produce and superheat
the steam necessary for supplying the large superheated steam heating
vessel, and are afterwards caused to pass round and heat the outer shell
of this vessel or heater, within which the duplex boilers are placed for
the purpose of being heated by the superheated steam, under a regular
pressure and temperature, instead of by the more irregular heated
products of combustion, as in the former modification described. The
superheating boiler may be of any of the forms and constructions
heretofore in use for superheating steam, but the arrangement of a
"stack" or set of vertical cast-iron pipes placed within a main heating
flue or chamber close to the furnace is preferred, having the steam
generated in the pipes of the vessel nearest to the furnace, or at their
lower parts, and superheated at the upper parts of the pipes or those
furthest from the furnace. From the upper and warmest part of these
pipes and superheating vessel the superheated steam is conveyed by a
main pipe to the interior of the superheated steam heating vessel
(containing the set of "fibre pulp" treating boilers), which is provided
with a small blow-off pipe and regulating cock at bottom to draw off
any water of condensation or wet steam or air which may collect in it.
The heated products of combustion, after acting on the superheater
and raising and producing the superheating steam, are made to pass
on through a main flue into the lower part of the annular flue space
between the brickwork and the outside of the large vertical steam
heating vessel (so as to further heat it and the superheated steam
within) as they circulate and ascend up round it on their way to and
before passing off to the funnels or chimney at the top of the brickwork.
In this latter arrangement (where the heat or temperature of the
heating steam is so susceptible of being regulated exactly by the
admission of more or less superheated or the ordinary saturated steam
into the heater, and by the regulation of the pressure within it) the
annular perforated lining or wire cloth vessel of the new construction of
fibre "paper pulp" boiler may be dispensed with in some cases when
desired. Two or more of these arrangements of new or improved fibre
pulp treating duplex boilers (whether heated in the said direct modes

page_text: by the action of the heated products of combustion or by superheated
steam within a surrounding close vessel) may be heated in their
respective close chambers from one furnace, each heating chamber and
boiler arrangement having a separate inlet and outlet flue damper, and
one spare flue with a damper for the whole set, leading direct from the
main flue of the furnace to the chimney.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Sinclair in the Great Seal Patent Office
on the 30th April 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
SINCLAIR, of the Town of Leith, in the County of Edinburgh, North
Britain, Boiler Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of November, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-third
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said George Sinclair, Her special licence that I, the
said George Sinclair, my executors, administrators, and assigns, or such
others as I, the said George Sinclair, 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 TREATING WOOD AND
OTHER VEGETABLE FIBROUS MATERIALS FOR THE PRODUCTION OF PAPER PULP, AND
IN THE BOILERS AND APPARATUS EMPLOYED THEREFOR," upon the condition
(amongst others) that I, the said George Sinclair, my executors or
administrators, 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 George Sinclair, do hereby declare
the nature of my said Invention, and in what manner the same is to he

page_text: performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Sheet of Drawings and to the letters marked thereon, and which I have
appended for the purpose of showing the best modes and means I am
at present aware of for performing or carrying my said Invention into
effect or practice, the same reference letters and numerals indicating the
same or like parts in all the Figures, that is to say :-
My said Invention consists, mainly and substantially, in the heating,
boiling, or first treating of the split wood, wood shavings, "esparto,"
and other vegetable fibrous materials mixed with the proper amount of
water and caustic soda or "lyes" usually employed for the kind and
quantity of fibrous materials being treated, in order to prepare them for
paper pulp" within new or improved constructions and arrangements
of close vessels or boilers, by the direct action or radiation of the heat
through the outer sides or shells of the said boilers, and in the con-
struction and arrangement of these boilers.
65
And in order that the nature of my said Invention and the manner of
performing the same may be properly understood, I shall now proceed
to describe the several illustrative Figures on the accompanying Sheet of
Drawings.
Figure 1 is a vertical section of one of my new or improved boilers
shown as erected with its heating furnace and mounting all ready for
the first boiling and treating or reducing of split wood, wood shavings,
"esparto," and other vegetable fibrous materials; and Figure 2 is a
horizontal section taken on the line 1-1 in Figure 1, both illustrative
of one modification of my said Invention; Figures 3 and 4 are re-
spectively a vertical and a horizontal section of another modification and
arrangement of my Invention or improvements, in which four of the
improved reducing boilers are set and heated within a superheated steam
vessel also shown as erected within its flue heating chamber with the
furnace and steam producing and heating apparatus or boiler and
mounting all attached ready for being set to work.
Referring to the modification of my Invention shown in Figures 1
and 2, each new or improved pulp preparing boiler A (to be used for the
said purpose by direct heating) is placed within a confined heating walled
flue or chamber B of brickwork B', having the heated products of com-
bustion from the furnace C passed into and through it, so as to act on
the outer surface of the boiler A, which has an inner casing or vessel D

page_text: formed of thin sheet metal plates (of a width removable through the
filling door) closely perforated all over with small holes, although in-
dicated only at the top and bottom parts at D', or this inner vessel D
may be formed of strong wire cloth when preferred, in either case it is
secured to the outer main close heating shell or vessel by small short
stays or studs, as D³, or it may be segmental or longitudinal feathers or
other equivalent, to retain the perforated vessel D at an inch or two off
or from the interior of the outer heating vessel A, all round and opposite
to where the heat impinges or is imparted to it. Thus the outer hot
shell A is prevented from touching, overheating, or burning the fibrous
materials which are all placed and kept within the inner perforated
vessel D, and so as to heat the liquor or " lyes" within the narrow
space a between the outer and inner vessels A, D, and cause it to
circulate freely up the space a over the open top, down the centre of the
perforated vessel D, and through the openings D', as indicated by the
arrows, all so as to pass vertically and laterally through the body of the
fibrous materials being treated, and thus thoroughly boil and reduce them.
For the treatment of some descriptions of fibrous materials which
pack too close for the liquid currents to circulate vertically and laterally
down through them as described, I prefer to insert a long perforated
tube d down the centre of the vessel D and materials in it, as shown in
red lines at d (in Figure 1) by preference close or only perforated at
the lower end to ensure the downward currents of liquid passing out
through the perforations d³ all down the sides, and laterally through the
materials being treated, all as indicated by the red arrows. It is preferred
to have the boilers A as shown of a long narrow cylindrical shape of
such a diameter that the contents would be easily heated from their
outer circumferences as stated (as, say, from two to four feet in diameter
and from three to six diameters in length) made of the best strong
malleable iron boiler plate with conical semi-spherical or other equivalent
strongly formed ends A¹ to stand the great pressure within, having at
the top A, and bottom A" respectively large filling and discharging
pipes or cylindrical doorways (by preference from eighteen to twenty
inches in diameter) with strong lids or covers A3 and A" easy of removal
and attachment, as by being screwed into their mouths or doors A³, A",
like an ordinary water plug or the breech of a rifle with turned flanges
(which however may be screwed by bolts passed through them when
desired), and made fluid pressure tight by fine grooves and rings of
copper wire or other equivalent simple joints. The large filling pipe or

page_text: door A, A, is by preference made to project up through the brickwork
B' at top vertically for the convenience of filling the vessel D, and
the discharge cylindrical door A", A", is placed horizontally out
through the brickwork B' at the lower end A' of the vessel A for the
more easy withdrawal of the solid fibrous matters laterally from the
inner vessel D into the portable or stationary vessels for subsequent
treatment. A small supply vessel E, by preference of spherical (or
it may be of a strong cylindrical form) is placed on the top and
above the boiler A and building B'. The extreme top of both
vessels A and E are connected by the small pipe E' and by another
small pipe E leading from the bottom of the supply vessel E into
a lower part of the fibre preparing boiler A and inner vessel D, both
pipes E¹, E³, being fitted with controlling sluice valves F¹, F. The
heating boiler A is built vertically in the heating chamber B of brick-
work B', with an annular flue heating space B all round it, and set on
its lower strong end, but it might also be hung by brackets to the brick
wall B at the top or sides when preferred. The flames and heated
gaseous products of combustion from the fuel and furnace C (which
may be of any ordinary construction) are by preference led into the
bottom of the heating space B either through the oblong holes C¹ in the
flame wall C, between the main entrance from the furnace C and the
lower part A' of the boiler A, or it may be directly or over the top of a
low wall C³, in which case there may be a lining of brick close to the
boiler at c, to protect it from the injurious action of the entering volume
of flame and gases, which after passing once round the lower part B of
the boiler A, and heating it rise up through the first horizontal division
roof at 6 into and back round the space b', up through the second division
roof 62 into and up round the space 6", and so on until they reach the
top 6* where the unutilized gases pass off into a chimney B³ on one or
both sides, all as indicated by the arrows, but when preferred they may
be taken off at a lower flue after passing over the top of the wall B' or a
high division or flame bridge by a suitable duct or flue which may be
led direct to an ordinary brick chimney. Either or both of the main
entrance, as at C2, and exit flue B2 to each heating chamber B may be
controlled by dampers, although such are not shown in these Figures.
The treating of the fibrous materials and action of the boiler A, D,
containing them, and this arrangement of improved apparatus generally
is as follows:-The cover A³ of the inlet and charging door A* is screwed
off, and the wood shavings, "esparto," or other fibrous material to be

page_text: treated is put into and retained within the inner perforated or wire cloth
vessel D with a sufficient charge of caustic soda, and the vessel A filled
up to the top with water in the usual proportions for this part of the
process, when the cover A³ is then firmly screwed down and the small
vessel E filled with water so as to keep the fibre preparing boiler A, D,
always full of liquid. The fire is then lighted in the furnace C and kept
burning slowly, the heated products of combustion passing over the flame
bridge C² and round and up the heating spaces B and (b, b¹, 11, 6111)
between the outer heating shell A of the boiler A, D, and the building B
to and out through the funnel B into the air or a brick chimney accord-
ing as arranged, so as to boil the fibrous materials and alkaline liquors
under the pressure for the required time and to the degree desired, the
boiling liquid being in continuous circulation through the fibrous
material being treated, as indicated by the arrows, after which the
lyes or alkaline solution may be drawn off by the small blow-off
pipe G and cock G¹ bolted to the lower part of the discharge mouth A",
protected at the entrance by the rose or perforated plate at G", but it
might be drawn off from the bottom A¹ in some cases. The lid Don
the large discharge duct A" may then be screwed off, and the fibrous
materials withdrawn from the inner perforated vessel D into the other
vessels for further treatment. Or otherwise when desired both the
"lyes" and fibrous materials may be withdrawn through the discharge
duct and door A".
"
Referring to Figures 3 and 4, the arrangement here shown consists
in inclosing a number, as four, of these new or improved duplex "fibre
pulp" treating or making boilers A, D, within a close outer cylindrical
superheated steam vessel H formed of strong boiler plate iron placed
vertically within an annular flue and flame-heating chamber B of brick-
work B (analagous to that described in reference to Figures 1 and 2 of
the former arrangement of a single boiler placed and heated or boiled
direct in a similar heating chamber). Each duplex boiler A, D, has a
filling door A and lid A³ projecting up through the top end of the
steam-heating vessel H and brickwork B³ for filling it with the fibrous
material and "lyes" to be treated, and has the long horizontal discharge
pipe A" with lid A projecting out radially through the side at the
lowest part of the steam-heating vessel H and brickwork B₁ of the flue-
heating chamber B, and either fitted with liquid discharge pipe and
valve G, G', or not, as desired, for the discharge of the said fibrous

page_text: materials and liquid after treatment, all substantially as described in
reference to Figures 1 and 2, except that the ends A¹ of the boilers A.
being small are made flat and yet capable of standing the high internal
pressure. The four boilers A, D, are directly connected to each other by
small cross pipes d, d', d", at the top and bottom respectively (or other
equivalent) within the steam vessel H to equalize the level, pressure,
and circulation of the liquid within the boilers so connected, one of
which has a small supply vessel E attached above, as described also in
reference to Figures 1 and 2, which, however, in this case serves for the
whole set of boilers thus connected, and insures their being full of the
circulating alkaline liquid above the fibrous materials being treated, all
so as to work well and equalize and circulate the heat and acting liquids
in each boiler, substantially as described in reference to Figures 1 and 2,
and indicated by the arrows in these Figures 3 and 4 as well. When
the boilers A, D, are thus connected in sets the liquid may be drawn off
from the whole at once, when the boiling or treatment of the fibrous
materials is completed by one blow-off pipe G and cock G' attached to
any one of the discharge pipes A" instead of to each, as shown in
Figure 1.
With the addition and use, however, of a stop-cock or valve
in the cross pipes d', du, both the liquid and fibrous material may be
withdrawn separately or together from each vessel individually by
discharge pipes and valves G, G¹, and mouth and door A", A", fitted
to each, all as more fully described in reference to Figures 1 and 2 of
the former modification. In any or all of these arrangements a small
water pipe all with stop-cock may be connected by a branch or branches
to the upper part of the outer shell A of these duplex boilers A, D, so
as to wash the annular space a between the outer and inner shells A.
and D occasionally when desired after one or more boilings or discharges
of the materials, as indicated in blue lines at a". In this arrangement
Figures 3 and 4, the heated products of combustion from the furnace C
are by preference first made to raise or produce the steam or superheated
steam (in any ordinary steam generator, as I) necessary for supplying
the large steam heating vessel H, and afterwards caused to pass into
and round the heating flue or chamber B of the outer heating vessel H,
so as to further heat the superheated steam conveyed to it from the
generator I. Although the generating and superheating boiler I may
be of any of the forms and constructions heretofore in use for super-
heating steam I prefer the arrangement herein shown, consisting of a
"stack" or set of vertical cast-iron pipes i set in rows steam-tight at

page_text: their upper and lower ends in transverse horizontal pipes j, j, all
jointed at their lower ends to the inlet water pipe k on one side and to
the outlet steam pipe k at their upper ends on the other side, all placed
within a main heating flue or chamber I' close to the furnace C. The
steam is generated in the set of pipes i of the vessel I nearest to the
furnace C, particularly at their lower ends, kept filled a considerable
way up with the water for that purpose fed in at the pipe k, but a part
of the pipes i at the top may be left for a steam heating space as well as
their transverse connecting pipes at the top, so as to highly heat the
steam therein by the direct action of the hot gases and flame before it
passes off by the main outlet steam pipe ¹ or otherwise, as I prefer a
few of the transverse rows of pipes furthest from the furnace as may
be disconnected from the water pipe k as indicated at k³, and made a
superheater for the whole of the steam generated in the front tubes i
connected at k³, so that the steam would pass through the pipes ¹
as a coil of heating pipes and be highly superheated before entering
the main pipe J (controlled by a cock or valve J¹) which conveys and
regulates its admission to the steam heating vessel H by preference
admitted near the centre of the bottom end at H', but it might be
admitted at any other convenient part of this vessel containing the four
boilers A thus heated through their outer shells by the radiation or
direct action of the superheated steam within the vessel H. A small.
blow-off pipe K provided with a regulating cock or valve K' is connected
to the bottom of the steam heater H at H for the purpose of carrying off
any wet steam, or the water thrown down by the condensation of the
steam in heating the boilers A. The four duplex boilers A, D, secured
steam-tight within the chamber H are thus heated by the said super-
heated steam which is maintained and regulated at the high temperature
sufficient to raise and boil the materials being treated within the
boilers A at the pressure and temperature required to reduce them to
the pulpy state desired. Although the superheated steam within the
vessel H must necessarily be of a high temperature it may be regulated
to any convenient and safe low pressure by the attachment of indicating
gauges and safety and automatic working pressure valves, which would
be fitted to these heating vessels A, H, and I (although not shown in
the Drawings) as in other and ordinary steam generators. In this
arrangement, Figures 3 and 4, therefore of heating the close boilers A, D,
by the direct action of superheated steam on their outer surfaces the
temperature and pressure of the heating steam within the heating

page_text: chamber H is more susceptible of automatic regulation than by the
direct action of the more irregular heated products of combustion from
the furnace C, as in Figures 1 and 2, therefore the inner perforated and
wire cloth vessel D may, in some cases, when preferred be dispensed
with. The heated products of combustion from the fuel and furnace C
after passing through the chamber I' and acting on the steam generator
and superheater I are made to pass on through the main flue L and
outlet controlled by the damper into the lower part of the annular
flue chamber B between the brickwork B¹ and the outer circumference
of the vertically disposed steam heating vessel H, so as to heat it and
further superheat the steam within as they circulate and ascend up
through the space B, shown as a spiral flue 61, 6, 61, formed by a
winding roof or thickness of brick 6 to the top 6', where they pass off
to the funnel or chimney B' and , all as indicated by the arrows in
Figures 3 and 4, but this flue B might also be arranged with division
roofs and openings, as indicated in reference to Figures 1 and 2, or
other equivalent arrangement of flue. Two or more of these arrange-
ments of boilers A, Figures 1, 2, or Figures 3, 4, heated in the same
direct manner through their outer shell and under pressure, either by
the actual products of combustion or by superheated steam within a
surrounding close vessel, may be heated in their respective close flue
heating chambers, as B, of brickwork in either case from one main
furnace C and flue, as L in Figure 4 (but made larger and longer when
several sets are to be heated therefrom), each heating chamber B of the
set having an inlet flue and damper in addition to
which is usually fitted with a damper also at the outlet
chimney B, or in this case led down the vertical flue
flue leading to a chimney for the whole set, the furnace or main flue L
having in this case one spare flue M with a damper M communicating
direct with the said chimney serving for the furnace and whole set of
boilers.
the top flue *
leading to the
to the main
Having thus particularly described the nature of my said Invention,
and the manner in which the same is or may be performed, I have to
state that I do not restrict myself to the precise details herein described
or delineated; but what I believe to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,―
First The construction arrangement and use of close boilers heated

page_text: by the direct action of the hot flame and products of combustion from
the fuel and furnace, in the manner and for the purposes substantially
as herein-before described.
Second. The construction, arrangement, and use of close boilers
heated by the direct action of superheated steam within a close heating
vessel, in the manner and for the purposes substantially as herein-before
described.
Third. The construction and use of close vessels or boilers with
internal shells or cases closely perforated or made of wire cloth,
in the manner and for the purposes substantially as herein-before
described.
Fourth. The construction and use of close boilers with conical ends
and a filling mouth piece at top, and lateral discharge tube and mouth
piece at bottom, in the manner and for the purposes substantially as
herein-before described.
In witness whereof, I, the said George Sinclair, have hereunto set
my hand and seal, this Twenty-sixth day of April, in the year
our Lord One thousand eight hundred and seventy.
GEORGE SINCLAIR. (L.S.)