IMPROVEMENTS. IN RAG ENGINES FOR PAPER MAKING
Year: 1884

page_text: 1 JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of the said Invention for "IMPROVEMENTS.
IN RAG ENGINES FOR PAPER MAKING" and in what manner the same is to bo
performed to be particularly described and ascertained in and by the following
statement:
This Invention relates to engines for beating rags and similar fibrous materials
into pulp for the manufacture of paper. In these inachines a beater roll set with
knives around its periphery is used in combination with a bed plate also set
with knives the said parts being placed in a tank or vessel in which a constant
circulation of the material to be pulped is maintained.
Heretofore, ordinarily, the material has been circulated horizontally around an
upright partition termed a mid-fellow and the beater roll and bed plate have been
placed in the alley or channel between this mid-fellow and one side of the tank.
The beater roll lifted the material over a sort of dam (termed a backfall) and the
material then flowed by the action of gravity around the mid-fellow and entered
again between the beater roll and the bed plate. It has however been proposed to
dispense with the mid-fellow and have the material return under the back tall and
bed plate. In either case the circulating force is that of the gravity due to the
piling up of the liquid or semi-liquid on the side of the back fall opposite from the
beater-roll. Consequently the flow is comparatively feeble and it is necessary to
use large quantity of water in order to prevent the fibre in suspension from
depositing.
In the present Invention a much more rapid and vigorous circulation is
maintained. The beater roll is placed at one end of the vat, which is of a depth
sufficient to contain it and the other part of the vat is divided by a horizontal
partition or division which extends froin the beater roll nearly to the other end.
The material to be pulped is carried around by the benter roll, and is delivered
into the upper section above the partition. It flows over the partition, then passes
down around the end of the same and returns through the lower section of the vat
to the beater roll.

page_text: The beater roll not only draws in the material creating a pat va
lower section of the vat but delivers it into the upper section with considerable
force impelling it forward very rapidly. By the aid of this more rapid as well as
inore vigorous circulation not only is the material returned more quickly and
therefore acted upon more frequently by the beater roll in the same time, but it
may be worked with a much less quantity of water and thereby important
advantages may be secured. These advantages are firstly in the improved quality
of the product for when a considerable body of the fibrous material is drawn
between the knives the different pieces are rubbed together and thus disintegrated
without destroying the length and felting quality of the fibre whereas when the
pulp is thin pieces are ground individually as it were, between the knives and the
integrity of the fibre in large measure destroyed: secondly in the greater
quantity of pulp which can be prepared in a machine of given size owing to the
larger preparation of fibrous material in the charge: and thirdly in avoiding the
liability of the fibrous material to deposit out of the liquid and lodge in the
channels.
The Invention consists in the new mode of and apparatus for circulating the
fibrous material and water, and it also comprises certain particular constructions
and combinations of parts as hereinafter set forth.
The accompanying Drawings represent a rag engine constructed in accordance
with the Invention. Figure 1 is a plan view with a part of the casing or vat
removed. Figure 2 a vertical longitudinal section. Figure 3 a plan of the bed
plate and Figure 4 a partial view in cross section.
The roll A provided with knives B set radially in the periphery is mounted on
the shaft C which is journalled in the sides of the vat D.
The vat is of any suitable length and in depth about equals the diameter of the
roll which is set in the vat close to one end of the same. The ends of the vat are
rounded. The beater roll is slightly eccentric to the curvature of the end of the
vat in order to give a clearance (see Figure 2) and allow the crude pulp to be lifted
with less difficulty.
The bed plate knives E are set in the shoe F which is fixed in or to the bottom
of the vat under the beater roll. The knives are separated by strips or blocks G of
wood or other suitable material and a number of these knives and strips are
fastened together by a curved bolt or rivet H. As shown the knives on each sido
of the middle are fastened together.
The shoe F has flanges I which are radial with respect to the axis of the beater
roll and form a dove tail. The two sets of knives with their spacing strips are
placed in the dove tail and are spread apart by the wedges K and L. Those
marked K are preferably of wood the wedge L of iron. The wedges K are first
inserted and the wedge L is driven between them.
When the bed plate knives become worn they can be set out by withdrawing
the wedges and placing strips or pieces under the knives. As they are moved out
the two sets of knives are drawn towards each other owing to the inclination of
the flanges I and it is necessary therefore to plane off a little of the wooden
wedges before replacing them and the iron wedge. The bed plate knives are
placed radially with respect to the axis of the beater roll, and are adjusted in
nearly radial planes.
The shaft of the beater roll turns in close boxes which are further provided with
collars M in order to make the joint liquid tight. Any ordinary or suitable means
can be used to adjust the shaft of the roll. Between the beater roll and the
opposite end of the vat is the horizontal partition N which extends to within a
short distance of the end of the vat. There is an upright inclined plate P which is
brought at the upper edge into close proximity to the beater knives but does not
touch them.
The vat is provided with the usual valve for withdrawing the pulp and also with
the pipe for supplying water. In the sides of the vat opposite tho ends of the bed
plate knives are curved slots through which the knives and wedges can be inserted

page_text: and withdrawn. In operation these slots are closed by blocks Q of corresponding
shape so as to fit the hole. The blocks are held in place by the plates R which are
bolted over the slots after the blocks have been put in force.
The operation of the engine is as follows:-
The beater roll and bed plate knives being adjusted properly the vat is filled
with the rags or fibrous material to be pulped and the proper quantity of water.
The beater roll being revolved at the proper speed (say for a roll four fect in
diameter at the speed of 120 revolutions per minute) the rags and liquid are drawn
between the knives are carried up by the beater roll and are thrown over the edge
of the plate P. They flow around the partition N with considerable velocity and
return again and again to be acted upon by the knives. The roll is revolved until
the pulp is properly reduced.
Modifications may be made in the details of construction without departing from
the spirit of the Invention and parts of the Invention may be used without the
others.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
First:—The improvement in beating rags to pulp in a rag engine having a
beater roll and bed plate knives consisting in circulating the fibrous material and
liquid in vertical planes drawing the same between the knives at the bottom of the
vat, carrying it around and over the roll and delivering it into the upper section of
the vat, substantially as described.
Second-A rag engine for paper making comprising the vat, the beater roll
mounted on a horizontal shaft and the horizoutal partition dividing the body of
the vat into an upper and a lower section or passage the fibrous material and
liquid being carried from the lower section between the knives and delivered over
the top of the beater roll into the upper section or passage substantially as
described.
Third-The combination of the bed plate knives the flanged shoe and the
wedges substantially as described.
Fourth-The combination with the beater roller, of the adjustable bed plate
knives arranged radially with respect to the said roll and the means for adjusting
the position of the said knives substantially as described.
Dated this 12th day of August 1884
J. HENRY JOHNSON,
47 Lincoln's Inn Fields, London W.C.