Improvements in Bed-plates for Beating Engines for Use in the Manufacture of Paper.
Year: 1898

page_text: Date of Application, 25th Jan., 1898-Accepted, 2nd Apr., 1898
COMPLETE SPECIFICATION.
Improvements in Bed-plates for Beating Engines for Use in the
Manufacture of Paper.
We, FRED EUGENE MAXFIELD, of No. 354, Maple Street, in the City of Holyoke,
County of Hampden, and State of Massachusetts, Manufacturer, and ELWYN WINSLOW
LOVEJOY, of No. 813, Broadway Street, in the City of Lowell, County of Middlesex,
and State of Massachusetts, Manufacturer, both in the United States of America, 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 bed-plates for beating engines used in the manufacture of
paper, and has for its object the production of a plate of this class in which the blades,
within prescribed limits of width, are given a maximum degree of inclination relative
to the axis of the beater-roll of the engine, and the blades of the plates so disposed as
to cause a uniform movement of the stock being operated upon from the ends of said
bed-plate towards the central line thereof, and whereby the stock is subjected to a
longer continued shearing or beating action between the roll and the blades of said
plate than has heretofore been possible.
The invention consists in the construction of a bed-plate as fully described and
claimed hereinafter.
In the drawing forming part of this specification,―
Figure 1 is a plan view of a bed-plate constructed according to my invention.
Figure 2 is a plan view of a bed-plate of the same width as that shown in Figure 1,
but of greater length.
Figure 3 is a cross section of a plate taken on line 3-3, Figure 1.
Figure 4 shows a modification.
Certain conditions prevail in the building of beating-engines for paper-stock which
make it necessary that said plates should not exceed a certain prescribed width,
though in beaters of varying capacity the length of said plates may vary considerably.
The aim of manufacturers of bed-plates is always to first so arrange the blades
composing said plates, relative to the axis of the beater-roll, as to produce a shearing
action between the blades of the roll and the blades of the bed-plate; and, secondly,
to so dispose the blades of the plate relative to the axis of the roll of the beater
engine that the course of paper-stock being worked will be from the ends of said bed-
plates towards the center line thereof.
The width of the bed-plates being substantially the same in engines of varying
capacity, and their length showing wide variations, it follows that a bed-plate for a
small beater, such as one shown in Figure 1, for example, may have opposite ends of
the blades thereof placed at a greater angle relative to the axis of the roll than the
blades of a bed-plate as long as that shown in Figure 2.
Assuming that the maximum width of the bed-plate is represented by the distance
from the base line x, to the points x1, x¹, of the opposite side of the plate, the greatest
efficiency of such a plate is attained by giving the blades a thereof such a degree of
inclination relative to the axis of the beater-roll or cylinder, and so disposed as to
give the fiber the longest course across said plate, and, consequently, subjecting said
fiber longer to the shearing or drawing-out action between said plate and the said
beater-roll.

page_text: The solution of this problem has been sought heretofore by making blades having
angular bends therein, said blades having been arranged sometimes in parallelism,
and sometimes at an angle to each other, but so far the only result of such construc-
tion has been the attainment of increased shearing action between the plate and the
blades of the roll.
The peculiar arrangement of the angular blades herein shown and to be described
accomplishes the above-mentioned sought for ends, viz.,-the maximum shearing
action, the continuous movement of the stock from the sides toward a central line of
the bed-plate, and means for giving to the stock the longest course diagonally across
the bed-plate, whereby a longer and more even fiber is produced and the time for
beating a given amount of stock is very much reduced.
In constructing the herein described bed-plate, the outside plates are made slightly
heavier than the plates clamped between them.
All the blades are given their proper angular bend and are then secured together
by the boits b; strips d, of wood or other suitable inaterial being interposed between
them in the ordinary manner.
The peculiar features of this construction consist, first, in making that part of the
blades between the ends thereof and the bends therein at x¹, longer than that part
between x and the center; and, second, in giving to that part of the blades
between x¹, and the center of the plate, a less degree of inclination than to the
portion between ¹, and the ends of the plate, and in reversing the angles thereof.
By reversing the angle of the blade between x¹ and the center of the plate, a
longer cutting edge on the blades a is provided and the dip of the angle between the
said two points is made as great as is possible, without materially arresting the move-
ment of the stock towards the center.
It has been found in practice that the best proportions of angles for the purposes
above described are substantially those shown in the drawing and are obtained by
dividing each half of the plate into three parts; and at substantially one-third of the
distance from the center toward each end thereof is located the point x¹, and the
distance between the base line x, x, and the bend of the first plate above said base
line, at x¹, is substantially one-third greater than the distance from said line to the
termination of the reversed angle at the center x², of the plate.
Whether the plate be long or short, the distance from the base line to the
points x and x, is practically the same, the angles being determined by the distance
from the point x¹, to the end of the plate and to the center thereof respectively.
The course of the paper-stock in a diagonal direction across the bed-plate as
specified, is due to two causes. First, the shearing action of the blades of the roll
against the inclined edges of the blades of the bed-plate gives the stock a lateral
sliding movement of greater or less extent towards the center.
If the angles of the bends in the blades of the plate are equal, and the lengths of the
bent portions are substantially equal, the stock will not have the same tendency to
travel toward the center of the plate as in the present construction, for the pulp in
the spaces between the blades of the bed-plate at each side of any angular bend in
said plate will be of about the same weight and will, therefore, travel from each side
of said bend to the apex of the angle and there seek to pass out in a straight line;
but a body of pulp of greater weight in the spaces between the blades on one side of
said angular bend, will overcome the resistance of the body of pulp of less weight on
the other side of said bend, and cause it to be forced back towards the center of the
plate and out between the blades of the beater-roll and those of the plate, thus causing
said pulp to travel farther diagonally across said plate than if the plate were con-
structed, as specified.
Second, the spaces a² between the blades a, of the bed-plate, which blades project a
certain distance above the blocks d, between said blades, constitute channels in which
the fiber travels, the movement of said fiber therein being set up by the action of the
blades of the roll constantly forcing the stock into said channels and by reason of
the inclined position of the latter towards the center of the plate.
When the stock in said channels arrives at the point x¹, where it meets the reverse

page_text: angle of the blade, and where the channel is diverted away from a straight line, the
tendency of the stock is to back up somewhat therein, and therefore that portion of the
plate between 21 and x², is made of smaller area than that part between x¹ and the ends,
for the backing up of the stock in the channels a², tends to force the stock out over
the edges of the blades a, more forcibly than on that part of the plate between the
ends and x¹, and to equalize the work of the rolls against the blades a, it has been
found, in practice, that the relative proportions of the two angular portions for pro-
ducing the maximum efficiency is substantially as shown and described herein.
If these proportions are varied to any great extent, it is found that the distri-
bution of stock along the bed-plate varies, and consequently the work of the engine is
uneven.
It apparent that a bed-plate constructed like that illustrated in Figure of the
drawings, would obviously come within the scope of this invention.
In said Figure 4, the series of angles are similarly arranged on each side of the
center line of the plate, transversely, and in gradually ascending series from the ends
of the plate towards the said center line.
That is to say, the lowest point of the second series of angular bends from each end
of the plate is higher than the lowest point of the end series, and the highest point
of the third series from each end is higher than the highest point of the
second series. Therefore, although the stock in its diagonal course across the
bed-plate from the ends towards the center of the plate is during that course deflected
towards the base line x, x, by the second series of bends in the blades of said bed-
plate, (meaning by that the second from the end of the plate) its general direction
is still towards the apex of the center of the plate, for at its lowest point in said
second series of bends, it is higher than the lowest point of the first series.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1. A bed-plate for beating engines consisting of a series of parallel blades secured
together, having reversed angular bends therein similarly disposed at each side of
the center of said plate, the angles of the end portions of the blades with the base
line of the plate being less acute than the angles of the central portions thereof, sub-
stantially as described.
2. A bed-plate for beating engines consisting of a series of parallel blades secured
together, having reversed angular bends therein similarly disposed at each side of the
center of said plate, both the angles with the base line of the plate and the lengths of
the central portions being less than the angles and the lengths of the succeeding
portions between the center and the ends of said plate, substantially as described.
3. A bed-plate for beating engines consisting of a series of parallel blades secured
together, similarly disposed on each side of the transverse center of said plate, and
having reversed angular bends arranged in ascending series relative to the base line
of the bed-plate, from the ends towards said center, the blades of each of said sections
being of equal length, and the angle of each section on one side of the said central
line of the plate coinciding with the corresponding section on the opposite side of said
line, substantially as set forth.
Dated this Twenty-third day of December 1907
FRED. E. MAXFIELD.
ELWYN W. LOVEJOY.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.