IMPROVEMENTS IN REFINING OR STRAINING PULP FOR MAKING PAPER, AND IN APPARATUS THEREFOR.”
Year: 1879

page_text: LETTERS PATENT to George Tidcombe, junior, of the Firm of "G. Tidcombe &
Son," Paper Makers' Engineers, of Watford, in the County of Herts, for the
Invention of "IMPROVEMENTS IN REFINING OR STRAINING PULP FOR MAKING
PAPER, AND IN APPARATUS THEREFOR.”
PROVISIONAL SPECIFICATION left by the said George Tidcombe at the
Office of the Commissioners of Patents on the 13th December 1879.
GEORGE TIDCOMBE, junior, of the Firm of "G. Tidcombe & Son," Papor Makers'
Engineers, of Watford, in the County of Herts. "IMPROVEMENTS IN REFINING OR
STRAINING PULP FOR MAKING PAPER, AND IN APPARATUS THEREFOR."
This Invention relates to improvements in refining or straining pulp for making
paper, and in apparatus therefor.
Although several kinds of rollers are used for pulping and refining the materials
of which paper is made, they each have knives or bars built in their circumferences
in clumps or wide apart, working against a bed-plate or other roller having bars,
also wide apart, and set too wide for the object of this Invention. The edges of
the bars are also at too great a distance from the body of the roller. Some portions
of the pulp therefore pass the grinding edges of the bars, or get between them and
do not become thoroughly finished.
The pulp is discharged into a chest or reservoir, and it afterwards passes through
a strainer or knotter to the paper making machine.
By this mode of pulping or "beating" it is necessary to employ large surfaces of
strainers or knotters, especially in making fine papers. These are worked by what
is called "vacuum pressure" or "suction," but it is an imperfect or limited pressure,
and great accumulations of pulp or knots have still to be dealt with; they also
produce "strings ""clots," or "lumps," at the underside of their plates which run
off with the good pulp and spoil the paper, especially in making fine, tinted, and
coloured papers.
The present Invention obviates these defects as follows:-
1. By catching, drawing out, and refining the pulp after it leaves the chest or
reservoir with a proper admixture of water and delivering it of an equal consistency
to the paper making machine by the use of a roller having grinding "molar teeth,”

page_text: or short facets formed out of its solid circumference short enough when working
over a suitable bed-plate or within a concavely curved grinding surface covering
a portion or the whole of its circumference, or against a second roller so as to grind
or refine even the smallest lumps. It thereby becomes in itself a grinding or
refining strainer.
This primary roller is made of chilled iron by preference, but may be of steel,
brass, or other suitable material, such as porcelain china of hard quality, and the
bed-plate, grinding surface, or secondary roller, against which the primary roller
refines the pulp, is made up of thin metal plates, by preference having dividers of
thick paper or card or of other suitable material, such as wood or soft metal, and
bolted solidly together. The roller and bed-plate are adjustable together.
2. By a rough method of making a roller on this principle, by turning the body
of a roller true, fitting bars into its circumference, and turning down the points or
edges of the bars closely enough to the body of the roller, so as to form the molar
teeth or facets above described. But this is an imperfect method, and does not
give the required accuracy for fine papers, although it answers in some degree for
browns and coarse papers.
It is to be remarked that by forcing diluted pulp when required through
revolving or other strainers with greater force and rapidity than by "vacuum
pressure" from an elevated head or at high pressure, by jets, streams, or otherwise
Í effect a more thorough and effective straining than can otherwise be obtained.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Tidcombe in the Great Seal Patent Office on the 12th June
1880.
GEORGE TIDCOMBE, junior, of the Firm of "G. Tidcombe & Son," Paper Makers'
Engineers, of Watford, in the County of Herts. "IMPROVEMENTS IN REFINING OR
STRAINING PULP FOR MAKING PAPER, AND IN APPARATUS THEREFOR."
This Invention relates to improvements in refining or straining pulp for making
paper, and in apparatus therefor.
Although several kinds of rollers are used for pulping and refining the materials
of which paper is made, they each have knives or bars built or formed in their
circumferences in clumps or wide apart, and work against a bed plate or other
roller having also bars wide apart and set too wide for the object of this Invention.
The edges of the bars are also at too great a distance from the body of the roller;
some portions of the pulp therefore pass the grinding edges of the bars, or get
between them, and are thereby carried through and do not become thoroughly
finished. The pulp is discharged into a chest or reservoir, and it afterwards passes
through a strainer or knotter to the paper making machine.
"
By this mode of pulping or "beating" it is necessary to employ large surfaces of
strainers or knotters, especially in making fine papers. These are of costly
construction and are worked by what is called "vacuum pressure or "suction,"
but it is an imperfect or limited pressure, and great accumulations of pulp or knots
have still to be dealt with; there are also produced "strings," "clots," or "lumps"
at the underside of these plates, which run off with the good pulp and spoil the
paper, especially in making fine, tinted, and coloured papers.
The present Invention obviates these defects as follows:-
1. By catching, drawing out, and refining the pulp either before or after it leaves
the chest or reservoir, and thinning or diluting the same in the latter case with the
proper admixture of water, for delivering it of an equal consistency to the paper
making machine by the use intermediately, of a roller having grinding molar teeth
or short facets, formed out of its solid circumference short enough when working
over a suitable bed plate, or within a concavely curved grinding surface surface
covering a portion or nearly the whole of its circumference, whereby it becomes
in itself a grinding or refining strainer, capable of grinding or refining even the
smallest lumps.
This refining roller is made of chilled iron by preference, but may be of steel,
brass, or other suitable material, such as porcelain china of hard quality (as used
in so called "cbina roller mills" for treating semolina in flour making), and the bed
plate or grinding surface, against which the refining roller works, and is set to refine
or reduce the irregularities of the pulp, is made up of thin metal plates, by
preference having dividers of thick paper or card or of other suitable material, such
as wood or soft metal, and bolted solidly together. The roller and bed plate are
adjustable together.
2. By a rough method of making a roller on this principle, by turning the body
of a roller true, fitting bars into its circumference and turning down the points or
edges of the bars closely enough to the body of the roller, so as to form the "molar
teeth" or "facets" above described; but this is a less perfect method and does not
give the required accuracy for fine papers although it answers in some degree for
browns and coarse papers.
It is to be remarked that by forcing diluted pulp when required through
revolving or other strainers with greater force and rapidity than by "vacuum
pressure" from an elevated head, or at high pressure by jets, streams, or otherwise,
there will be effected a more thorough and effective straining than can otherwise be
obtained.

page_text: In working according to the above process I usually cause the pulp or stuff to be
strained coarsely before entering the usual regulator or stuff pump, so as to keep
back the coarse lumps, threads, unbeaten rags, or foreign matters, and this strainer
or strainer plates is or are placed outside or within and flush with or forming the
bottom of the chest itself; when outside it is kept clean by by ordinary means, and
when inside or forming the bottom of the chest by a brush or scraper revolving over
it by the action of the chest agitator.
In Sheet 1 of the accompanying Drawings Fig. 1 represents the ordinary rollers
with the knives or bars built into or formed in the circumference in clumps, and
working against a bed plate formed with corresponding bars.
Fig. 2 represents my improved grinding refining-roller A with molar teeth or
facets B working over the laminated bed plate or grinding surface C; Fig. 3
represents the roller A. formed by turning down the points or edges of the bars of
the roller similar to Fig. 1, to form the "molar teeth" or "facets" B¹ similar in
character to Fig. 2. The flow of the pulp is in the direction indicated by the
arrows.
In Fig. 4, Sheet 2, A represents a roller running against the bed plate or
reducing surface C, said bed plate being made of thin steel plates and having card-
board or paper fillings, as already described, or being solid and having in either case
molar teeth or facets B with intervening dwells of graduated size, as shown, or not
graduated formed upon the upper surface of the said bed plate C, adjacent to the
chilled iron roller A, said roller A being grooved with shallow grooves parallel with
the body of the roller or diagonally of the surface, or otherwise, as illustrated in
Figs. 5 and 6, which grooves may be etched, that is, burnt out of the chilled iron
roller by acids or be worked out by diamond points or runners into the form, as is
well understood.
By this construction of refining roller A and bed plate C the pulp is drawn out
or rasped through the narrow parts or facets B or B' and the face of the bed
plate C, and the coarser portions or knots, which are the parts which it is specially
designed to reduce and treat, are continually forced back against the bottom or
grinding plate by the centrifugal action of the roll A.
In Figs. 7 and 8 is represented in side view, partially in section and plan
respectively, the Invention applied to the paper making machine.
D is a pipe leading from the stuff box and coarse strainer to the mixing box E
fitted with sluice E¹, and into this box is introduced for mixing with the coarsely
strained pulp water in sufficient quantity for reducing the pulp to the density
requisite for delivering it to and upon the paper machine "wire' a which travels
over the breast roll b, and intermediately of this mixing box E and the paper
machine is the refining roller A and grinding surface or bed plate C mounted upon
standards and within the box F. The bearings of the shafts A¹ of roller A are
indicated in dotted lines, Fig. 7, and provided with wedge and screw bolt adjust-
ments, as will be well understood, for adjusting the periphery of roller A in relation
to bed plate C, said roller A being driven by strap and pulley or otherwise as
convenient. G is the feeding trough provided with division plates G¹ for receiving
the refined pulp directly from the refining roller and quieting same ready for
delivery on to the breast roll for feeding. Within the trough F and bearing against
the sides of the refining roller A are provided packing bands or strips F¹ which are
laid into channels or grooves, as shown in Fig. 8, and at the back of the bands Fi
within said channels is laid a flexible backing, consisting preferably of lengths of
india rubber tube, for purpose of holding said packing bands F' against the ends of
roller A and preventing all passage of pulp except between said roller A and bed
plate C.
In Figs. 9 and 10 is shown a modification of fitting. The mixed pulp is delivered
from the mixing box E into a quieting trough E and thence into a sand catcher H
fitted with upright dividing plates to intercept and catch any heavy particles, or
the pulp may be delivered directly into said sand catcher, and in this sand catcher
trough H is mounted a skimming plate or knife I which serves to catch and skim.

page_text: off any floating impurities from the pulp. The plate I is trimmed off to a knife
edge which is adjusted to meet the top of the flowing stuff; the blade is at a slight
incline upward and backward to the trough K. of the skimmer, into which the
skimmings will be gradually washed up and run away therefrom by way of end K¹.
The ends of the skimmer blade have rivetted or attached thereto flexible strips L
of leather, rubber, or rubber cloth, which will bear against the sides of the sand
catcher trough H. The other parts of the apparatus are substantially the same as
before described and are marked with corresponding letters of referenco to those in
Figs. 7 and 8, but two quieting or feeding troughs G are shown. According to a
further modification of fitting the pulp box F, Figs. 7 and 8 and 9 and 10, may be
covered over airtightly and the pulp be forced therein either from an elevated head,
or under air pressure, or by pump, and so any tendency to froth the pulp before
delivery from the box will be counteracted by the even discharge ensured.
When required. two or more of these refining roller machines can by the pressure
be employed in the course of the flow of the pulp and be set to different degrees of
fineness for purpose of increased treatment of the stuff.
By these ineans the paper pulp may be refined and delivered on to the paper
making machine free from all strings, clots, or lumps, or danger of spoiling the
paper thereby, and as illustrating the results to be obtained, it is to be remarked
that the ordinary knots or accumulations of pulp that have heen rejected by the
strainer used according to old process may be passed through this improved refining
apparatus and used directly for paper making.
Having now described the nature and particulars of my said Invention in such
wise that the same may be readily carried into practical effect, I claim,-
Firstly. The use of the refining roller A with molar teeth or facets B or B¹
working over or against the bed plate or grinding surface C for reducing or refining
the pulp, substantially as herein set forth and described in reference to Figs. 2
and 3 of the Drawings.
Secondly. The use, in combination with the roller A, of the bed plate C having
formed therein dwells and corresponding molar teeth or facets, as herein described
and shown in Figs. 4, 5, and 6 of the Drawings.
Thirdly. The herein described roller A, bed plate C, pulp box F, and roller
packing F, said roller A being mounted in adjustable bearings for setting the
roller A in relation to the bed plate C for purpose of reducing pulp.
Fourthly. The apparatus for refining or straining pulp for making paper, as
herein described in reference to and shown by Figs. 7 and 8 and 9 and 10 of the
Drawings, in combination with the paper making machine, as and for the purpose
herein set forth.
Fifthly. The feeding of the pulp under pressure into an airtight box F, F¹, of
refining roller A and bed plate C, as described and for the purpose herein set
forth.
In witness whereof, I, the said George Tidcombe, junior, have hereunto set
my hand and seal, this Eleventh day of June, in the year of our Lord One
thousand sight hundred and sighte
Witness,
WALTER A. BARLOW,
Patent Agent & Engineer,
6, St. Paul's Churchyard,
London, EC.
G. TIDCOMBE, JNR. (L.S.)