IMPROVEMENTS IN THE MEANS OF AND APPARATUS FOR THE BOILING OR PREPARING OF ESPARTO, GRASS, AND OTHER MATERIAL USED IN THE MANUFACTURE OF PAPER
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by David Smith and Charles Robertson
at the Office of the Commissioners of Patents on the 6th May 1882.
DAVID SMITH and CHARLES ROBERTSON, both of The Cone Paper Mills, Woolaston,
Lydney, in the county of Gloucester "IMPROVEMENTS IN THE MEANS OF AND
APPARATUS FOR THE BOILING OR PREPARING OF ESPARTO, GRASS, AND OTHER
MATERIAL USED IN THE MANUFACTURE OF PAPER"
This Invention relates to certain "Improvements in the means of and apparatus
for the boiling or preparing of Esparto, grass and other material used in the
manufacture of paper" the object being to increase the effect at the same time that
a lesser quantity of steam chemical and time are requisite for bringing the liquor
to boiling point and to secure that the liquor is maintained at more uniform
strength.
In carrying the invention into practice we apply a multitubular steam chest or
chamber in the bottom of the boiler used for the boiling or preparing of esparto,
wood, rags and ropes or other vegetable fibre.
In the boilers now in use for the boiling or "cooking" of vegetable fibre for the
purposes of paper making, the boilers are filled to a certain extent with a solution
of caustic liquor, and a perforated false bottom is fixed near the bottom of the
boiler which is thus always standing full of liquor which is more or less idle.
Under this plate there is a steam pipe by means of which steam is introduced into
the said idle or bottom liquor the which very shortly becomes weakened by the
steam condensing during the boiling. The steam has to mix with or blow into
the liquor until it is raised to a certain heat when it blows or vomits up through a
vomit-pipe" supported on a perforated false bottom, the liquor thus vomited
spreads itself over the esparto or other fibre at the top of the boiler and becomes
cooler and returns by gravitation to the bottom of the boiler into the idle liquor
under the false bottom and is then sent up again after being made hot by the
contact of the steam but this is a very imperfect action. characterized by the
following defects :-firstly;-The chemicals owing to the condensation of steam in
the liquor diluting it has to be made extra strong at first to make up for its
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declining strength during the time it is boiling or cooking"-Secondly :-It takes
much steam to get it to boiling or vomiting" point which causes loss of steam
and time. Thirdly -The liquor being so diluted with the steam when it has to
be evaporated to recover the soda in an Incenerator or evaporator much extra fuel
heat and labour has to be used for the quantity of soda recovered.
The multitubular steam chest or chamber which we employ is placed in the
boiler either below the perforated false bottom or without the false bottom being
present. The chest or chamber is employed to receive the steam which is led into
the same by a steam pipe and the space is intersected with tubes around which the
steam circulates said tubes being brazed secured or fastened into top and bottom
Above the
plates of the chest or chamber or it may be the side plates thereof.
chest or chamber there is in some cases placed a hood or cover with a vertical
standing pipe which will be and serve the purpose of a "vomit "pipe.-A second
pipe is applied leading from the chest or chamber for exhaust steam and
condensed water. The pipes are supplied with suitable cocks.
This improved means and apparatus for effecting the boiling treatment of the
vegetable fibres is characterized by the following advantages.
Firstly. Great saving of chemicals as the liquor is always kept at uniforn
strength in the boiler the steam having no contact with the liquor as in the old
system.
Secondly. Owing to the liquor not being diluted by steam it keeps its strength
until the fibre is boiled and by the violent circulation between the hot steam
pipes and hot plates wherein they are fixed much less liquid is required in the
boiler and as a natural consequence less soda will be used for the same quantity of
material there is no useless or idle liquor in the bottom of the boiler when
boiling as in the old system as nearly the whole of the liquor is kept in suspension
among the fibre.
Thirdly. The improvements can be applied to all revolving boilers and all kinds
of boilers at present in use for the manufacture of paper pulp.
Fourthly. The pipes in the tubular chest or chamber can be of any shape Conical,
Taper, or can be expanded in the middle the depth of the steam pipe chamber or
chest and the number of pipes being regulated by the length and diameter of the
fibre boiler.