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Патент USA US3077320

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Feb- 12, 1963
Filed Dec. 51. 1959
Z/ya/ f/arn basis!
United States Patent 0 M1C6
Patented Feb. 12, i953
Lloyd Hornbostel,‘ Eeloit, Wia, assignor to ltleloit iron
in abrasive engagement with pulpwood supported by said
pocket, producing as among the advantages reduced stone
ll’orirs, Beloit, Wis, a corporation of Wisconsin
Filed Dec. 31, 1959, is‘cr. No. 863,295
2 Claims. (Cl. 241-280)
Another object of the instant invention is to provide
apparatus for grinding pulpwood to obtain pulp there—
from, comprising a rotatable grinding member, a hous~
ing for pulpwood positioned adjacent said grinding mem
ber, force applying means for advancing said pulpwood
into grinding contact with said grinding member, and
The present invention relates broadly to the art of
pulp production, and is more particularly concerned with
novel method and apparatus for grinding pulpwood fea 10 means for effecting relative movement between said
turingmovement of a pulp stone and pocket relative to
grinding member and housing to vary the contact area
one another, whereby there is obtained'pulp of consistent
of said member in abrasive engagement with said pulp
ly uniform quality at substantial power economies.
wood, whereby frequency of sharpening of said grinding
Since the advent of the early pulpwood grinders using
member and the magnitude of grinding pressure varia
j-ackscrews and a car jack for maintaining pressure and 15 tions to attain quality control are reduced.
down to the modern high production magazine grinders
A further object of the invention lies in the provision
and continuous grinders of the ring or chain feed types,
of a method of grinding pulpwood, which comprises ad
it has been found dif?cu'lt to produce consistently uniform
vancing a plurality of pulpwood sticks into abrasive en
pulp. One explanation for this is the great number of
gagement with a rotatable grind member.
variables in the pulping process, and among those of
Other ‘objects and advantages of the invention will
considerable importance are the‘ sharpness of the pulp
become more apparent during the course of the following
stone, the moisture content of the pulp wood and the
description, particularly when taken in connection with
pulpwood density.
To explain, an accepted control used in the manufac~
ture of pulp is “freeness” or measurement of the drainage
Since all pulp is at one time in a sus
the accompanying drawings.
In the drawings, wherein like numerals designate like
parts throughout the same:
FIGURE 1 is a top plan view of the apparatus effec
pended form, in order to make a sheet of paper the water
tive to practice the instant method, and incorporating
must be removed, and'theease or lack of ease with which
a conical grinding member and a pulpwood pocket which
this mixture, or slurry,,will drain is referred to as free—
is moved laterally with respect thereto;
ness or slowness. A free stock is usually composed of 30
FIGURE 2 is a fragmentary end View ‘to illustrate the
relatively long, coarse ?bers, or is a stock from which
grinding action on a pulpwood stick at the relatively
the ?nes or ?ours (gelatinous bits of fractured ?bers)
larger radius of the conical pulp stone of FIGURE 1;
have been removed; while a :slow stock generally con
sists of short, ?ne, well-?brillated ?bers intermixed with
FIGURE 3 is a view similar to FIGURE 2 and show
?nes. Now, in pulp grinding, freeness changes markedly
from the time of sharpening the pulp stone until sharpen~
ing is again required. The sharp stone tends to cut the
?bers and decrease‘the‘?nes, whereas as‘the stone be
ing the grinding action at the relatively smaller radius
of the conical grinder stone.
As earlier stated, it has been dif?cult in the past to
obtain consistently uniform pulp quality at reasonable
comes worn, the extent of cutting decreases and the rub
power expenditures, due to the greater number of vari
bing and re?ning action has the e?ect of producing more 40 ables involved in the pulpwood grinding process. The
?nes and greater ?brillation‘;
freeness or measurement of pulp drainage characteristics
The variable of pulpwood‘ moisture content bears im
changes substantially from the time of stone sharpening
portantly on the‘ e?iciency of‘ the pulping operation,
until it again becomes necessary to sharpen said stone,
since when the wood is relatively wet the ?bers separate
since it is now known that a sharp stone tends to cut
more easily, their strength'is greater and ‘the power con
the?bers and decrease the ?nes, whereas as the stone
sumption is lower. While eitorts are made by soaking
becomes Worn, the amount of cutting decreases and the
or like procedures to have at least 30% moisture content,
rubbing and re?ning action tends to increase, producing
it is apparent that this condition cannot always be attained
more ?nes and greater ?brillation. On the other hand,
and a uniform moisture content for a particular load of
the variations in pulpwood moisture content and density
pulpwood cannot be e?iciently accomplished, even when
require that the grinding pressure or unit loading be
pre-soaking is used.
varied, and by reason of the relatively great contact area
Accordingly, to compensate for moisture content and
of the conventional grinder pocket, wide pressure varia
density variations, while striving for consistently uniform
tions or large changes in loading are necessary. This
pulp quality, the grinding pressure or unit loading is ad
markedly increases the total power requirements for the
justed or varied. The pulpwood pocket, however, of
grinding process, and a point is approached at which
the prior art presents a relatively large contact area both
mechanical pulp grinding loses some of its economical
arcuately and axially, and the power requirements to vary
the loading are therefore substantial. As is known, the
It has now been discovered that uniformly consistent
e?iciency of the pulping process is expressed in terms of
pulp quality at minimum power expenditures is ob
horsepower per daily ton of ?ber, and it can therefore
tained by varying the contact area of the pulp stone and
be seen that when wide variations in grinding pressure
pulpwood relative to one another, so that pulp stone Wear
or load required to obtain optimum unit loading for
is reduced and the stone remains in relatively sharp con
consistent pulp quality are necessary, the pulping ef
dition for a longer period, and thereby continues to out
?ciency is substantially diminished.
It is accordingly an important aim of the present inven 65 rather than rub the ?bers.
The relative movement described can be accomplished
tion to provide method and apparatus for pulpwood grind
ing productive of uniformly consistent pulp quality at
minimum power requirements.
by moving the grinder pocket laterally with respect to
a generally conical grinder stone, or in other Ways which
will become immediately apparent to those skilled in the
Another object of this invention lies in the provision
of improved structures and procedures for producing 70 art upon a consideration of the instant disclosure.
The apparatus is illustrated in FIGURE 1 and is close
pulp, wherein the pulp stone and pocket are moved rela
ignated therein generally by the numeral Fill. As shown,
tive to one another to vary the contact area of said stone
there is provided a pulp stone or grinding member 71 of
parallel with the pocket and sticks being abraded, con
generally frusto-conical con?guration supported for rota
voluted pulp stories may of course be employed and in
this case the motion of the pocket can be relatively slower
and the power requirements would of course be reduced.
tion at opposite ends by shaft means
72a journaled
in bearing means 73——73a, respecdvely, said pulp stone
71 being driven in rotation by motor means or the like
'74} having shaft means '75 coupled at ‘7'6 to shaft means
77 received in the bearing means 730.
To vary the grinding contact area, a grinder pocket
or housing 73 is provided with guide means 79 received in
This and other variations and modi?cations, including tie
use of more than a single grinder pocket for each pulp
stone, may of course be practiced without departing from
the novel concepts of the present invention.
1 claim as my invention:
1. Apparatus for grinding pulpwood to obtain pulp
track means
disposed generally parallel to the grind 10
therefrom, comprising a generally frusto-conical grind
ing surface of the conical grinder 71. The pocket 78
ing member, means for rotating said grinding member,
is laterally reciprocable along the track
and suitable
a housing for pulpwood positioned adjacent said grind
motive means for this purpose may take the form of a
ing member, force applying means connected to said
double acting cylinder
having ports 6“?
\Lw and 33 admit
housing for advancing said pulpwood into grinding con
ting pressurized ?uid to opposite sides of a piston 845.
tact with said grinding member, track means disposed
having a rod portion
connected either directly to
generally parallel to the surface of said grinding mem
the grinder pocket 78 or to the guide means '79 thereon.
ber and receiving said housing for movement .therealong,
Pulpwood (not shown) in the pocket ‘it? is urged into
and motive means reciprocating said housing along the
abrasive engagement with the conical grinder 71 by
means shown in FIGURE 1 as comprising a cylinder 20 track means and laterally with respect to said grinding
35 provided with ports 3% and S7 to reciprocate a piston
ti?» with arm portion
connected to plate means 8%
bearing against the pulpwood sticlzs.
member to vary the location of grinding contact of said
member with said pulpwood, whereby frequency of sharp
ening of said grinding member and the power require
ments to effect grinding are reduced.
Buring lateral movement of the grinder pocket 78
2. A pulpwood grinding mechanism comprising in com
along the track 89, the pulpwood sticks in the pocket 25
73 are continuously subjected to a changing stone radius,
in the manner indicated in FEGURES 2 and 3. The
bination a grinding rotor having a generally frusto-coni
pulp stone ‘71 has a relatively large radius end 71:; and
a relatively smaller radius end 7122 between which the
the rotor in rotation about its axis, a support for pulp
pulpwood sticks continuously travel under action of the
motive means 81 for the grinder pocket 78.
By reason
of the continuously changing grinding surface in abrasive
engagement with the pulwood, no single area or band
along the pulp stone is subjected to greater Wear, and
the stone 71 accordingly longer retains a good “tooth”
and the fibers from the pulpwood are cut, rather than
cal grinding surface, rotating driving means for driving
wood adjacent said grinding surface for holding pulp
wood in grinding contact with a portion of the length of
said surface, means operatively associated with said sup
port for moving said pulpwood support toward the sur
face to hold the pulpwood in grinding contact, and linear
drive means operatively associated with said support rela
tively moving the support in a general axial direction
parallel to the grinding surf-ace to progressively change
the axial location of grinding contact between the pulp
wood ‘and grinding surface whereby the pulpwood pro
a relatively small pocket 78 is utilized, presenting to the 40 gressively engages areas of the grinding surface of chang
ing diameter.
changing grinding radius a relatively smaller contact
area than has heretofore been employed with the result
References Cited in the ?le of this patent
that not only is the sharpening eriod prolonged, but the
power requirements to maintain the optimum unit loading
Burghardt ____________ __ Feb. 23, 1869
or grinding pressure at the nip is markedly less than has
rubbed, so that a minimum amount of ?nes are produced.
it may be observed upon reference to FEGURE 1 that
previously been the practice.
It is apparent from the foregoing description that si
multaneous movement of the grinder member and pulp
wood sticlrs relative to one another can be accomplished
in numerous ways utilizing various structures. The 50
ground pulp is of course collected in any convenient man
ner, and thereafter subjected to conventional processing
steps. The apparatus disclosed functions effectively on
all known wood employed for mechanical pulping, and
Schmidt _____________ __ Apr. 23, 1889
Eilers, Jr _____________ __ Apr. 30, 1889
Roberts _____________ __ Nov. 10, 1896
Aicher ________________ __ Dec. 4, 1923
Germany ____________ __ Nov. 22, 1882
Norway ______________ __ Mar. 9, 1925
ermany ____________ .._ Nov. 25, 1889
Germany _____________ __ May 6, 1936
substitution for generally ?at grinding suriaces lying
France ______________ __ Feb. 24, 1929
customary pre-treatrnent may be utilized as desired.
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