IMPROVEMENTS IN BOILERS FOR TREATING FIBROUS SUBSTANCES FOR THE MANUFACTURE OF PAPER
Year: 1874

page_text: LETTERS PATENT to Benjamin Brown, of Cardiff, in the County of
Glamorgan, Paper Maker, for the Invention of “IMPROVEMENTS IN
BOILERS FOR TREATING FIBROUS SUBSTANCES FOR THE MANUFACTURE OF
PAPER."
Scaled the 14th July 1874, and dated the 4th May 1874.
PROVISIONAL SPECIFICATION left by the said Benjamin Brown at
the Office of the Commissioners of Patents, with his Petition, on
the 4th May 1874.
I, BENJAMIN BROWN, of Cardiff, in the County of Glamorgan, Paper
5 Maker, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN BOILERS FOR TREATING FIBROUS SUBSTANCES FOR THE MANUFActure of
PAPER," to be as follows:-
This Invention relates to an improved construction of rotary boiler in
which fibrous substances are intended to be treated for the purpose of
O reducing the same to half stuff..

page_text: The boiler I make cylindrical, and fit it at its ends and also at the
middle of its length with bearing rings, which resting on flanged anti-
friction rollers mounted in suitable base plate bearings will support the
boiler in a horizontal position, and thus avoid the necessity for the use
of trunnions to carry the boiler.
The boiler I heat externally by the fires of two or more fire chambers
which partially enclose it near its ends, which fire chambers are
provided with the usual appliances of a furnace. The only openings in
the boiler will be those covered by the man-holes and by the safety
valves.
The boiler is fitted internally with blades or plates which extend
nearly the whole length of the boiler, and which are so arranged as to
assist in filling the boiler by conducting the charge away from the man-
holes, and discharging the boiler by guiding the contents when
sufficiently operated upon towards the man-holes, whence the same will
fall into tanks situate below the boiler. These blades acts also as
agitators, throwing the contents of the boiler away from or towards the
interior periphery, according to the direction of rotation imparted to the
boiler.
To render the boiler thoroughly efficient it is desirable to rotate it
alternately in opposite directions during the maceration of the fibres,
and when the process is complete to rotate the boiler continuously in
one and the same direction in order to discharge the contents through
the opened man-holes.
These variations of rotary motion I propose to effect by the following
mechanism: Surrounding the boiler at the middle of its length is a
worm wheel into which gears a worm keyed to a horizontal shaft below
the boiler. This shaft is furnished with a fast band pulley and two
loose band pulleys of greater breadth than the fast pulley. A sliding'
band shifter furnished with two forks is mounted in front of these band
pulleys, its duty being to shift one or other of two driving bands (one of
which is crossed) from the loose pulleys on to the fast pulley. This
band shifter receives an endway motion (in opposite directions) alter-
nately from a tappet on one of a pair of worm wheels. Into these
wheels gear right and left handed worms keyed on to the same shaft,
and this shaft receives motion through its fixed pulley from a band from
the shaft that drives the first-mentioned fixed pulley.

page_text: So long as rotary motion in opposite directions is required to be given
to the boiler all the gearing just described will be in action; but when
the boiler is required to rotate continuously in one direction, the rotation
of the right and left handed worms is stopped and the worm wheels and
their tappets are thrown out of action.
The boiler, when charged with fibrous materials and the requisite.
chemical solvents through the man-hole doors, is slowly rotated by the
means described, so that all its contents will be subjected to a uniform
treatment and temperature, and to enable the workman to determine
the progress of the operation. Gauges both for the pressure and for the
temperature of the boiler are provided.
A strong tube with a closed end is fitted to each end of the boiler, the
open end of which receives a thermometer bulb, and pressure gauges
are connected to the opposite ends of a tube which extends transversely
through the boiler and is plugged at both ends to allow water to be
supplied thereto. The water in this tube being exposed to the same
heat as the contents of the boiler will indicate by its expansion the
pressure within the boiler.
Situate above the boiler in the plane of rotation of the safety valves
are inverted trough-like shields leading downwards to the tanks below.
These are for the purpose of preventing the waste of the chemical
substances employed, which in the event of the safety valves lifting
and their escaping from the boiler will be discharged into the tank
below.
When the fibrous materials in the boiler have been sufficiently boiled
the steam is allowed to escape. through a stop-cock into a pipe which
conveys the steam through a coil situated in a cold water tank. Thus
heat is imparted to the water, and the chemicals contained in the steam
are passed in a condensed form into another tank, whence they are
taken for the after recovery of the soda.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Benjamin Brown in the Great Seal Patent Office
on the 4th November 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
BROWN, of Cardiff, in the County of Glamorgan, Paper Maker, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Fourth day of May, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Benjamin Brown, Her special licence
that I, the said Benjamin Brown, my executors, administrators, and
assigns, or such others as I, the said Benjamin Brown, 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 BOILERS FOR TREATING FIBROUS SUBSTANCES FOR THE MANUFACTURE OF PAPER,"
upon the condition (amongst others) that I, the said Benjamin Brown,
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 Benjamin Brown, 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 Drawing hereunto
annexed, and to the letters and figures marked thereon (that is to
say) :-
This Invention relates to improved apparatus for reducing fibrous
substances to pulp to be used in the manufacture of paper.
The fibrous material which I propose to employ may be of various
kinds, as for example, pine and other soft woods, bamboo, wheat and

page_text: rye straw, esparto, flax waste, rope, rags, &c. In converting these
materials into pulp I employ the novel construction of apparatus shown
in the accompanying Drawings.
Fig. 1, Sheet I., is a side elevation of the apparatus; Fig. 2 is a
sectional elevation of the same taken in the line 1, 2, of Fig. 1.
Fig. 3, Sheet II., is a plan of the boiler and the mechanism for
working the same; and Fig. 4 is a transverse section taken in the
line 3, 4, of Fig. 3.
A, A, is a long cylindrical boiler fitted at its ends and also at the
middle of its length with bearing rings which rest on flanged anti-
friction rollers mounted in base plate bearings B, B, and thus serve to
support the boiler in a horizontal position. By this arrangement the
necessity for using end trunnions, as heretofore, to carry the boiler is
avoided, and the limit set to the length of the boiler is by this arrange-
ment materially extended.
C, C, are fire chambers or furnaces used for heating the boiler. These
furnaces partially enclose the boiler near its ends. Care flues leading
from the furnaces to a horizontal chamber D formed beneath an elevated
closed tank E. The chamber D and tank E rest upon girders carried by
the cast-iron pillars F. This tank E is intended to receive water for
supplying the boiler from time to time, and it is heated by the waste
products of combustion conducted off from the furnace by the flues C
to the chamber D, through which they circulate on their passage to the
chimney G. a, a, are the covered man-holes through which the boiler
is filled and emptied; b is a safety valve, and c a blow-off cock for
discharging the steam into the tank E.
Immediately above the boiler is an iron floor I in which holes are
formed (above the man-holes a) to receive pendent funnels, shown by
dots at d, for guiding the materials forming the charge through the
man-lioles into the boiler A. When the boiler is filled these funnels are
removed to allow of the free rotation of the boiler. K is a curved or
zig-zag plate or blade fitted to the inner periphery of the boiler and
extending nearly the whole of its length. This blade is intended not
only to act as a stirrer of the contents of the boiler, but also to distribute
the charge of fibre over the boiler, and to facilitate the filling as well as
the discharge of the boiler. When emptying the boiler this blade
facilitates the discharge of the solid contents of the. boiler into the

page_text: tanks H below by guiding the material (when the operation of separating
the fibres is completed) towards the open man-holes while the rotation of
the boiler is continued. The blade K is set radially in order that it may
throw the contents of the boiler away from or towards the interior
periphery according to the direction of rotation imparted to the boiler.
Supposing it is intended to convert wood fibres into pulp by means of
my improved apparatus I proceed as follows:-I first reduce the wood
to the form of chips by means of a rotary chopper of any approved con-
struction, and the wood thus reduced I charge into the boiler with a
solution of caustic soda, the strength of which may vary according to
circumstances; but in practice I have found that about four hundred-
weight of soda to one ton of wood material will generally suffice. I
next boil up to a pressure of not exceeding one hundred and sixty
pounds, maintaining the pressure for say an hour. After this I empty
the contents of the boiler into the tanks H which are fitted with
perforated false bottoms to allow of the liquor being drained off from
the pulp. This liquor is. valuable by reason of the soda which it
contains in solution, and which is recoverable for subsequent use. To
effect the recovery of the soda I run the liquor into an open pan, which
may conveniently be heated by the waste heat from an adjacent
reverberatory furnace, and when so much of the water has been
evaporated as to reduce the liquid to about the thickness of syrup I run
off the same from the pan into the reverberatory furnace where it is
exposed to the action of a naked fire. As the result of this action I
obtain soda ash which I dissolve in hot water and make caustic by the
addition of lime, and thus render it fit for re-use, adding fresh caustic
soda to maintain the liquor at the strength required.
It should be remarked that to render the boiler thoroughly efficient it
is desirable to rotate it alternately in opposite directions during the
maceration or boiling of the fibres; and when the process is complete to
rotate the boiler continuously in one and the same direction in order to
discharge the contents thereof through the opened man-holes.
These variations of rotary motion I propose to effect by the following
mechanism :-Surrounding the boiler at the middle of its length is a
worm wheel e, into which gears a worm f keyed to a horizontal shaft g
below the boiler. This shaft is furnished with a fast band pulley h, and
two loose band pulleys h¹ and ² of greater breadth than the fast pulley.

page_text: i is a sliding band shifter furnished with two forks and mounted in fixed
guides in front of these band pulleys, its duty being to shift one or other
of two driving bands (one of which is crossed) from the loose pulleys to
the fast pulley, and thereby to reverse the direction of rotation of that
pulley. This band shifter receives an endway motion (in opposite
directions) alternately from tappets & carried by a pair of worm wheels /
striking against a tail piece i pendent from the sliding bar of the band,
shifter. Into these wheels gear right and left handed worms m, m,
keyed on to the shaft n, and this shaft receives motion through its fixed
pulley o from a band from the shaft that drives the fixed pulley h.
So long as rotary motion in alternately opposite directions is required
to be given to the boiler all the gearing just described will be in action,
but when the boiler is required to rotate continuously in one direction,
the rotation of the right and left handed worms m is stopped and the
worm wheels and their tappets are thrown out of action.
It will now be understood that the boiler when charged with fibrous
materials and the requisite chemical solvents, as above described, is
slowly rotated so as to subject its contents to a uniform treatment and
température, to enable the workmen to determine the progress of the
operation gauges both for the internal pressure and for the temperature.
of the boiler are provided. Thus fitted to each end plate of the boiler is
a strong tube p with its closed end projecting inwards. These tubes
receive through their open end a. thermometer bulb, the mercury in
which will indicate the temperature of the contents of the boiler. So
also pressure gauges q are connected to the opposite ends of a tube r
which extends transversely through the boiler, and is plugged at both
ends to allow water to be supplied thereto. The water in this tube
being exposed to the same heat as the contents of the boiler will indicate
by its expansion the pressure within the boiler.
Situate above the boiler in the plane of rotation of the safety valve is
an inverted trough-like shield L leading downwards to the tank and
pendent from the floor I. This shield is for the purpose of preventing
the waste of the chemical substance employed, which, in the event of
the safety valve lifting and its escaping from the boiler, will be
discharged into the tank below.
:
When the fibrous materials in the boiler have been sufficiently boiled.
the steam is allowed to escape through a stop-cock c preparatory to

page_text: discharging the contents of the boiler. The steam may be led off by a
pipe to a coil situated in the water tank E, and it will thus assist in
heating the water. From this tank the steam may be passed to a con-
denser, and the condensed water thereby obtained may be made to yield
up the soda it contains by evaporation.
Having now set forth the nature of my Invention of "Improvements
in Boilers for Treating Fibrous Substances for the Manufacture of
Paper," and explained the manner of carrying the same into effect, I
wish it to be understood that under the above in part recited Letters
Patent I claim, the construction and fitting of boilers as above described,
whereby I am enabled to subject fibrous materials to a regulated steam
pressure, and keep such materials in continued agitation while under
treatment for the conversion of the same into pulp, and afterwards to
discharge the pulp automatically into receiving tanks or vessels.
In witness whereof, I, the said Benjamin Brown, have hereunto set
my hand and seal, the Third day of November, in the year of
our Lord One thousand eight hundred and seventy-four.