US1971335A - Apparatus for refining of raw materials - Google Patents

Description

Allg. 28, 1934. R. Q BENNER ET AL 1,971,335

APPARATUS FOR REFINING OF RAW MATERIALS Filed Deo. l, 1932 mM/E'W'ff/Mf/ -H 4 y Mg;

I s INI/lvToRs Raymond C enncf: A/bcr L Ball.

A TTORNEY Patented Aug. 28, 1934 UNITED STATES 11 Claims.

This invention relates to the art of disintegrating substances and more particularly to refining engines for ore dressing and paper pulp refining. For the purpose of brevity, the following disclosure is directed, in general, to the treatment of pulps for paper or board making.

The pulp consists of a mass of fibers obtained from various materials of vegetable origin depending on the grade of paper which it is desired 0 to make. The manufacture of paper consists of a number of stages which begin with the isolation of the fibers from the raw materials, which process generally requires both physical and chemical treatments. The object of these treatments is therefore to obtain a more or less pure cellulose that can be separated into individual fibers which can be readily bleached or further processed. This mass of separated fibers is called pulp or half-stuff.

It is necessary to refine this pulp for a number of reasons such as: f

(1) reduction in length and-diameter of'flbers; (2) further hydration of the fibers; `and (3) division of the ends ofA 'the ,fibersv into briuae., ,y j I The so-called hydration of the fibers tends to make the resultant paper more or less transparent. In the case of rag pulp, the splitting up of the ends of the fibers into fibrillaeis of use in making la strong paper sheet. Refining machines for the treatment of pulp consist essentially of a rigidly mounted shell (haw ing av frustoconical inner surface) andla frustoconical plug which is rotated within the shell. The internal surface of the shell and the external surface of the plug. are formed with sets of knives projecting inwardlyI and outwardly, respectively, in such a way that clearance is left for passage of the pulp between the shell and the plug. A small clearance tends. to cause cutting of the fibers while a somewhat larger clearance produces a rubbing or tearing action on` the fibers. The plug is mounted on a shaft driven by suitable shell. 'Ihe plug is also mounted in such a way that it can be adjusted axially to establish a fixed clearance between the respective sets of knives. This arrangement also serves to take up knife wear as well as to make the machine adaptable for processing coarse or fine grades of pulp stock. The refining engine has cap and pipe fittings to adapt it to receive a fiow of paper pulp and water. Means areI also provided for passing the pulp through the opening between the shell and plug and for then discharging the refined pulp into means for rotating the plug rapidly within the- PATENT OFFICE APPARATUS Fon REFINTNG oF RAW I,

MATERIALS Raymond C. Benner, Niagara Falls, and Albert L. Ball, Lewiston, N. Y., assignors to The Cal;- borundum Company, Niagara Falls, N. Y., -a corporation of Pennsylvania Application December 1, 1932, serial Ne. 645,178 f ,(ol. :a2-zi) suitable pipe lines by means of which the pulp is carried to other processing machinery. y

The refining engine which has just been described is subject Ato uneven wear on the knife Y edges since the pulp entering the spaces between 'the shell and the plug exerts more resistance to I the beating action of the knives than is the case after the pulp has become partially refined.

It has been proposed to use abrasive linings for the interior portion of the shell and the external portion of the plug, these abrasive linings being composed of artificially bonded abrasive having great toughness or resistance to attrition.A Even With linings of this character the clearance be-` tween the linings may be so large that the pulp passes between them with no refining action, or` i the clearance may be so small thatethe pulp is ground to an almost powdery condition. Extreme difficulty is thus experienced in the effort to adjust clearance so that the desired refining action 15 Will take place. Abrasive linings have, therefore, disadvantages as ordinarily used, someof which disadvantages have just been mentioned.

In carrying out the present invention, means are therefore Aprovided to cause an endwise or longitudinal oscillation of the plug relatively to the shell of any refiner, the purpose of this being to alter the clearance between the rotating plug and the shell within selected limits.

. The undesirable extreme conditions under which the pulp passes through the engine without being rened (or under which it becomes pulverized) are thus prevented. `With the endwise oscillation of the plug, it is also possible to feed coarser material through the machine than is possible where the plug is maintained at a xed axial position and to obtain a greater degree of refining throughout a-given run.

Another improvement which is embodied in the refining engine disclosed in the present application consists in making the shell and plug linings in sections/the'sectionswhich are subjected to the most severe attrition being detachable and readily replaceable.

Our improved refining engine is illustrated by the accompanying drawings in which:

Figure 1 is a sectional elevation of refining apparatus, the section being taken in a vertical plane through the axis of rotation of the plug;

Figure .2 is a section taken on the line II--II of Figure 1; and

Figure 3 is a view similar-to Figure 1 illustrating a modified refining apparatus.

Referring to the drawing in detail, a shaft 2 -is slidably mounted in a stationary shell 3. This shell is made up from a plurality of sections 4, 5 and 6 which are connected to form a rigid shell by means of screws 7. The sections 5 and 6 of the shell may be lined with articially bonded abrasive as indicated at 8 and 9 respectively. The sectional lining 8 may be cemented to the shell section 5 by means of cementing material not shown in the drawing (such as sulphur) which may be poured in a liquid condition between the lining and shell. The combination of the members 5 and 8 forms a replaceable unit which may be constructed or located at any place which is subject to more wear than the other portions of the shell.

The plug 11 is rigidly attached to the driving shaft 2 and can be oscillated in an axial direction by means of a rotatable cam 12 which acts on a cam follower 13 which is rigidly mounted in an adjustable manner on the shaft v2. Pulp may enter the refining engine at 14 and gradually pass through between the stationary shell and rotating plug to an exit at 15. The flow of the pulp may be eected partly by gravity and partly by pumps which can be placed outside of the refining engine in positions not shown in the drawing.

As the pulp passes between'the rotating plug and the stationary shell, it is alternately subjected to more severe stresses and to less severe stresses as the shaft 2 and the plug l1 are oscillated.` The most severe stresses occur while the pulp is in close contact with the sectional lining 8 and the opposed section 16 of the plug. As the section 8 becomes worn, it can be replaced after the supporting sections of the shell have been detached at '7. These supporting sections may be made as complete annul or in the form of split collars.

Section 16 of the plug 11 can be replaced in a similar manner. may be cemented to the detachable member 17 which can be removed from the plug after loosening the screws 18.

'The more permanent portions of the linings may be cemented to the shell or to the plug with a cement such as sulphur. Molten sulphur may also be run in between the abrasive sections on the shell and in between those on the plug. The shell and its lining thus become a strong unit. The same considerations apply to theplug lining and its support.

If abrasive linings are used, they can be formed using silicon carbide, fused alumina or other hard abrasive grain and a bond which is resistant to the disintegrating action of Water. Phenol condensation product resins are examples of bonding materials which show considerable resistance to the solvent action of water, provided the latter is not teo hot. Ceramic bonds are also well adapted to these uses. It is also possible to cast non-bonded molten abrasives into suitable shapes.

While for convenience of description the shell has been shown as stationary and means have been shown for giving axial oscillations to the plug, these conditions can be reversed so to keep the plug in a fixed axial position during the operation oi the engine while the shell is oscillated back and forth in an axial direction.

In the modification shown in Figure 3, the pulp is forced between the plug and the shell, the pulp entering where the radius of the gap is smallest and leaving where the radius is largest.

Since the lining is subject to more severe stresses Where the pulp enters between the plug and shell, the sections of the lining which are subjected to these severe stresses can, particu- In this case the plug section 16' larly in the case of abrasive linings, be made of harder and tougher and of finer grained material than the remaining sections of the lining. The hardness and toughness of an abrasive article depend on the character of the abrasive lused (silicon carbide, fused alumina, quartz, etc.)

and also depend on the constituents of the bond and the relative proportions of abrasive and bond. With a given type of abrasive and a given type of bond, the toughness of the resultant article can be increased by using finer abrasive -grain and a larger percentage of bond. For example, in the form of the refining engine shown in Figure l, the section of the shell lining where the pulp enters the machine can be made of a vitried section or ring containing finer mesh abrasive than the remainder of the shell lining and containing a larger percentage of bond than the remainder of the shell lining. Similarly, the plug can be provided with a section 16 of harder and tougher abrasive opposed to the correspondin section of the shell.

Other methods of oscillating the shaft 2 can be used. For example, an end of the shaft may be in contact with a cam which rotates about an axis perpendicular to that of the shaft 2, resilient means being used to hold the shaft 2 in contact with the cam in such a way that the shaft will be oscillated in an axial direction,

the period of oscillation being equal to the period of rotation of the cam. Our invention is not limited to any particular means of inducing oscillation.

As compared with ordinary pulp refining en gines, our improved refining engine has a number of advantages such as the periodical increase of stress on the pulp as. it is Worked between the abrasive linings. Other important features of our improved refining engine are to be found in the replaceable sections of the shell and of the plug and in the improved refining action and llonger wear obtained by utilizing stronger materials of the proper grain size at the points cf greatest reiining action.

We claim:

1. A pulp rening engine comprising in combination a shell, a plug adapted to rotate within said shell and around the axis of said shell, and meansor oscillating plug along the common axis to vary the clearance between the plug and l shell whereby Ythe pulp is subjected to periodi-- cally recurring stresses in passing between said. shell and plug in a continuously repetitive manner.

2. A pulp refining engine comprising in combination a shell having an internal abrasive lin ing with a frustoconical inner surface, a plug having a frustoconical outer surface adapted tol fit in said shell with small clearance, means for rotating said plug about the axis of said shell. 1

and means for oscillating said plug in the direction of its axis of rotation to vary the clearance between the plug and shell.

3. A pulp rening engine comprising in combination a sectional shell having an abrasive lining cemented to each section of the shell, the two sections of the shell being detachable from each other for replacement purposes but com binable to form a cavity with frustoconical sur- 1 face, a plug adapted to fit in said shell with small clearance, means for rotating said plug within said shell, and means for omillating said plug in the direction of its axis of rotation, wheret by the clearance between said shell and plug can par be periodically decreased and increased alterysis nately in a continuously repetitive manner.

4. A pulp refining engine comprising in combination an abrasive shell and an abrasive plug adapted to rotate within said shell and around the axis of said shell, the portions of the shell 6. The pulpreflner described in claim 4 in whichl the hardestv and toughest abrasive portions are replaceable.

7. A refining engine having two abrading members one of which is rotatable with respect to the other, while the clearance between the two members is periodically varied by axial oscillation of one ofthe members.

8. A pulp refining engine comprising in com' bination a sectional abrasive shell having a frustoconical inner surface and a sectional abrasive plug having a frustoconical outer surface and adapted to rotate within said shell with adjust; able clearance while the .pulp is forced between plug and shell, the sections which contact with the entering pulp being made of nner abrasive -thxaln the remaining sections. and means by which the plug is oscillated inan axial direction to vary the clearance between the shell and the plug.

9. A pulp refining engine comprising in combination a sectional shell having internal abrasive linings forming a frustoconical surface which surrounds pulp under treatment, a sectional abrasive plug having a frustoconical outer sur- :face adapted to fit in said shell with small clearance, means for rotating said plug and shellrelatively to each other with respect to a common axis, and means i'or oscillating the shell and plug relatively to each other in the direction of their common axis, the sections of the shell and plug adjacent to pulp entrance being tougher and harder than the remaining portions of the shell and plug respectively.

10. A pulp refining engine comprising in combination a shell having an internal abrasive lining with a frustoconical inner surface, an abrasive-surfaced plug having a frustoconical outer surface adapted to nt in said shell with small clearance. means for rotating said plug about the axis of said shell, and means for oscillating said plug in the direction of its axis of rotation to vary the clearance between the plug and shell.

1l. A pulp refining engine comprising in combination a sectional abrasive -shell having a frustoconical inner surface and a sectional abrasive plug having a. frustoconical outer surface and adapted to rotate within said shell with adjustable clearance while the pulp is forced between -plug and shell. the sections which contact with the entering pulp being made of abrasive bonded with a higher percentage of bond than the remaining sections-and means for oscillating the plug in an .axial direction to vary the clearance between the shell and plug.

RAYMOND C. BENNE'JR..` ALBmT L. BALL.

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