Improvements in Rag-engines for Use in the Manufacture of Paper.
Year: 1897

page_text: Date of Application, 1st Dec., 1897
Complete Specification Left, 26th Aug., 1898-Accepted, 22nd Oct., 1898
Improvements in Rag-engines for Use in the Manufacture of Paper.
I, STEFANO FRANCESCO VERRINA, of Voltri, in the Kingdom of Italy, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in rag-engines employed in the manu-
facture of paper; the object of the invention being to obtain a more efficient and
economical operation.
Rag engines, as commonly known are receptacles provided with a separating
diaphragm and in one of the parts separated by this diaphragm, a cylinder or
drum is arranged, which is rotated about its axis.
This cylinder has blades provided radially upon its cylindrical surface. Below
this cylinder a base is provided, which is likewise furnished with a certain number
of vertical knives or blades, similar to those arranged on the cylinder or drum.
Into the rag engines thus constructed the material for forming the paper-pulp
is introduced and as the cylinder rotates, it forces the pulp material down against
its blades and those of the base thus gradually crushing and reducing the material
to a homogeneous pulp.
The characteristic feature of this invention is relative to the special arrange-
ment of the blades upon the cylinder or drum and the base.
The blades heretofore employed were flat plates arranged parallel and sometimes
obliquely to the axis and were slightly tapering and sharpened upon their crush-
ing edges, so as to produce a certain cutting effect. The object of sharpening
such blades being that, in order to obtain an efficient action, the thickness of the
edges should be relatively limited. If such blades were formed so as to present
an equal thickness all over their extent, they would, in the majority of cases not
be sufficiently resistant; to avoid this defect, the blades usually receive a con-
siderable thickness near their base, and are gradually diminished in thickness
toward their cutting edges.
The improvement consists in imparting to these blades a corrugated shape,
the relative position of these blades being such that their undulations so corre-
spond with each other that the concave portions of the one blade lie opposite the
concave portions of the other and the convex portions of the one lie opposite the
convex portions of the other.
When the cylinder is in motion, the blade on the cylinder or drum travels
towards those on the base, and during this movement the hollow spaces formed by
each two corresponding corrugations, become constantly diminished, thus com-
pressing the pulp material contained between them, while the sides bearing against
each other further act upon the compressed material somewhat like scissor blades
which are continually opened and closed. Owing to this combined action the
crushing of the pulp material is much more efficient, the result being that the
product obtained is much more evenly reduced and in a shorter time than was
possible, when blades with straight planes were employed.

page_text: The use of corrugated blades offers still further advantages, viz. :—
On using such corrugated blades which in themselves possess a greater rigidity,
it is possible to employ blades of a constant section and as thin as a knife edge.
In this manner the material worked upon, is reduced to a lighter specific weight,
and another essential factor being that the blades, so constructed, need not be
re-sharpened in proportion as they wear; for, as they present a constant section
they always retain their original uniform knife edges.
As the corrugations of the cutting edges subject the pulp material to an action
analogous to that of scissors, the result is that, on setting the blades of the cylinders
and those of the base at the same distance apart from each other as in the case
of other blades, the crushing operation will be too strong and the material consti-
tuting the pulp will loose in resisting quality. In order to obtain a thorough
crushing of the pulp material by using corrugated blades, this distance may be
much wider, consequently the resistance opposed to the cylinder, as it rotates,
is diminished and the motive power required for working such rag-engine is
reduced.
1008
I, STEFANO FRANCESCO VERRINA, of Voltri, near Genova, in the Kingdom of
Italy, Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
This invention relates to improvements in rag-engines employed in the manu-
facture of paper; the object of the invention being to obtain a more efficient and
economical operation.
My invention is illustrated in the accompanying drawing in which:
Figure 1 is a plan.
Figure 2 a longitudinal vertical section, and
Figure 3 is an enlarged view of the corrugated blades.
Rag engines, as commonly known and used are receptacles provided with a
separating diaphragm BC, and in one of the parts separated by this diaphragm,
a cylinder or drum D) is arranged, which is rotated about its axis EF.
This cylinder has blades provided radially upon its cylindrical surface. Below
this cylinder a base G (Figure 2) is provided, which is likewise furnished with
a certain number of vertical knives or blades, similar to those arranged on the
cylinder or drum D.
Into the rag engines thus constructed the material for forming the paper-pulp
is introduced and as the cylinder D rotates, it forces the pulp. material down
against its blades and those of the base thus gradually crushing and reducing
the material to a homogeneous pulp.
The characteristic feature of this invention is relative to the special arrange.
ment of the blades upon the cylinder or drum D and the base G.
The blades heretofore employed, were flat plates arranged parallel and some
times obliquely to the axis EF and were slightly tapering and sharpened upon
their crushing edges, so as to produce a certain cutting effect. The object of
sharpening such blades being that, in order to obtain an efficient action, the

page_text: thickness of the edges should be relatively limited. If such blades were formed
so as to present an equal thickness all over their extent, they would, in the
majority of cases not be sufficiently resistant; to avoid this defect, the blades
usually receive a considerable thickness near their base and are gradually
diminished in thickness toward their cutting edges.
My improvement consists in imparting to these blades a corrugated shape.
Figure 3 represents two such blades, constructed in conformity with my inven-
tion, seen in plan, the one, for instance HI appertaining to the cylinder D and
the other L M belonging to the base G. This figure represents the said blades
in a position such as respectively occupied by them in the machine, the relative
position of these blades being such that their undulations so correspond with each
other that the concave portions of the one blade lie opposite the concave portions
of the other and the convex portions of the one lie opposite the convex portions of
the other.
When the cylinder is in motion, the blade on the cylinder or drum HI travels
towards the blades L M on the base in the direction indicated by the arrow, and
during this movement the hollow spaces formed by each two corresponding corru-
gations, for instance b¹a¹, ba become constantly diminished, thus compressing
the pulp material contained between them, while the sides for instance b¹ a¹ bear-
ing against the corresponding sides ba, further act upon the compressed material
somewhat like scissor blades which are continually opened and closed. Owing
to this combined action the crushing of the pulp material is much more efficient,
the result being that the product obtained is much more evenly reduced and in a
shorter time than was possible, when blades with straight planes were employed.
The use of corrugated blades offers still further advantages, viz. :-
On using such corrugated blades which in themselves possess a greater rigidity,
it is possible to employ blades of a constant section and as thin as a knife edge.
In this manner the material worked upon, is reduced to a lighter specific weight,
and another essential factor being that the blades, so constructed, need not be
re-sharpened in proportion as they wear; for, as they present a constant section,
they always retain their original, uniform knife edges.
As the corrugations of the cutting edges subject the pulp material to an action
analogous to that of scissors, the result is that, on setting the blades of the cylinder
and those of the base at the same distance apart from each other as in the case
of other blades, the crushing operation will be too strong and the material consti-
tuting the pulp will loose in resisting quality. In order to obtain a thorough
crushing of the pulp material by using corrugated blades, this distance may be
much wider, consequently the resistance opposed to the cylinder D, as it rotates,
is diminished and the motive power required for working such rag-engine is
reduced.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
In rag-engines for use in the manufacture of paper, the arrangement of
corrugated blades, applied, both, on the cylinder and on the base of the engine,
in such a manner that as a blade of the cylinder arrives above a blade of the base,
the corrugations of the one blade do not arrive opposite the corresponding
corrugations of the other, but alternate with each other.
Dated this 26th day of August 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.