US2858990A - Rotor with spaced large shredding blades cooperating with toothed stator - Google Patents

Description

Nov. 4, 1958 R. B. HONEYMAN 2,858,990

ROTOR WITH SPACED LARGE SHREDDING BLADES COOPERATING WITH TOOTHED STATOR Filed July 29, 1957 3 Sheets-Sheet 1 INVENTOR.

ROBE RT BLAKE LEY V HONEYMAN ATTORNEY,

Nov. 4, 1958 v R. B. HONEYMAN 2,858,990

ROTOR WITH SPACED LARGE SHREDDING BLADES COOPERATING WITH TOOTHED STATOR 3 Sheets-Sheet .2

Filed July 29, 1957 INVENTOR. ROBERT BLAKE LEY HONEYMAN ATTOR N EY United States Patent C) ROTOR WITH SPACED LARGE SHREDDING COQPERATING WITH TOOTHED Robert B. Honeyman, Portland,,0reg., assignor to Morden Machines Company, Portland, reg., a corporation of Oregon ApplicationJuly 29, 1957,,Serial No. 674,751 4 Claims. ((312.241-260) must be broken up, shredded and slushed, and the fibers in= the-material should:be:subj'ected to'a certainamount of refiningaction:

The invention relates specifically to" the particular type of machine-for shreddingi and treating" fibrous material to be-usedin paper manufacture-as described in; U. St Patent No. 2,654,294 to C.- W. Morden, issued unden'date of Qctober: 63,1953, andentitledPulp Shredding and Treat ing Machine, and reference should be made to: this:

earlier patentv for a. full: understanding of the present invention.

In-the device of theabove mentioned patent, Non.

2,654,294, the shredding and treatingofthe'fibrous-pul'p material are accomplished by means of arrot'or operating" in conjunction with a stationary impingementring, the:

stationary'ring haV-inga comically-shaped attritioning sur-' face, the rotor having peripheral blades which move over this stationary attritioning; surface, and the under sides of the rotor blades so-located; as to liein a conical surface capable; of matingwith the attritioning surface ofthe stationary ring.

The blades of the rotor, in thedevice of the above mentioned patent, are designed to serve the double purpose of impinging material stationary ring andof cooperatingwith the stationary ring in subjecting the fibrous material to an attritioning action between the rotatingblades and the stationary ringsurface, and, under optimum conditions, this double purpose is accomplished toa large extent by the device described in the patent. In-such a-device the blades on the rotating rotor must of necessityrbe fairly close together in order to perform the desired attritioning action in the short lengthof time during which the fibrous materialis-in contact with the conicalor attritioni-ng surface of the'stationary ring, and in consequence the pieces of the fibrous material must firstof. all be small enough to pass down between the blades of the rotor so as-to reach the attritioning surface on the stationary-ring; the, material to be'trea-tedincludesa considerable amount of moderately large pieces or slabsof'such fibrous mate rial, as is frequently the case, these larger pieces or slabs.

will collect on the rotor, or bridge over porarily until they are sufiiciently broken this interval they. actas ablock to the smaller particles of material and act as an impediment performance of the intended function of the has beenfound that this condition may exist to such an extent temporarily thatthe circulation'set up' through the blades of the rotor will be reducedlargely to water and the rotor, temconsequently during suchtemporary interval the machineoperation is far from:being eflicient.

of such materiall for use in the manufacture of paper'and related products, the materialagainst the conical surface of the- However, when up, and during in the proper: machine. It

Various attemptshave been made to achieve more efii'= cient operation of the machine by relieving such condi t-ions and reducing the-time required for the breaking up of such largerpiecesof fibrous material, including increasing therotor speed. However, these have not proved a satisfactory solution to the problem, and furthermore a considerable increase in the speed at which the-rotor is driven results in the use of a greater amount of power at increased ratio'of power consumption to' rotor speed.

An object of the present inventionaccordingly is to facilitate and hasten the breaking up of larger pieces of slabs of material, in a pulp shredding and treating maa chine of the type mentioned, without requiring any very extensive changes in the overall constructionof such'ma chine, and without even-changing the number or spacing of the rotor blades which are considered most desirable for the particular machine size or given installation, and

withoutvarying the important and necessary cooperation" tive circulation of the material through the'rotor blades andover the attritioning face of the stationary ring.

These objects and' otherincidental advantages are attainedbychanging some of the rotor blades to make them-extend up'beyond the top edges of amajorityof the blades=onthe rotor so as to encounter'the-l'arger pieces or bundles of fibrous material before these larger pieces" are ablet'o' c ollect-to such extent as'toblock the passage of material down between the rotor blades te-th'e attri tioning ring, but without making any change in the size orposition of the'under sides of the higher blades" or any changes in the spacing between the blades, andby'other' specific construction features as hereinaftenmentionedl This improved rotor construction, or rotor blade" construction, of the present invention,will be described and explained briefly with reference to the accompanying drawings.

In the drawings:

Figure 1 is an elevation of the improved rotor shown in its operation relationship with the stationary attrition'-. ing'ring of the pulp shredding and treating machine;

Figure 2 is a corresponding elevation'of the stationary ring by itself, for the purpose of making the other figures clearer;

Figure 3 is a section through the improved rotor and stationary ring taken-on the line 3-3 of Figure 1;

Figure 4 is a fragmentary section through the rotorwithoutthe stationary attritioning ring, taken on the line 44 of Figure 1, showing one of the standard blades of the rotor in elevation;

Figure 5 is a fragmentary section through the rotor without the attritioning ring, taken on line' 5-5'of Figure 1; showing one'of the special blades of the rotor in side elevation;

Figure 6' is'an outer end view of one of the standard bladessonthe rotor taken onthe line indicated at 6 6 inFigure l;

Figure 7 is a corresponding end view, drawn tothe same scale as Figure 6, of the outer end of oneof' the special bladeson the'rotor taken on the line indicated at 77 in Figure-1;

Figure 8 is a fragmentary side elevation of the rotor taken on line;8'--8 ofFigure l, with the stationary attri tioning-v ring omitte'dxfor the sake of clarity, showing one of the standardtblades; and

Figure 9'is a-similar fragmentary side elevation of the totor taken on line 9--9 of Figure 1 showing one of the special blades.

Referring first to Figures 1 and 3, the rotor, indicated as a whole by the reference character 10, has a front, substantially conical, or dome-shaped, face with a series of peripheral blades. Preferably, but not necessarily, the rotor comprises a main central integral casting 11 (Figure 3) having a rearwardly-extending central boss 12 formed with a tapered bore to accommodate the tapered end of the driven rotor shaft 13, to which the rotor is keyed, and having a dome-shaped nut 14, secured in place on the end of the rotor shaft and in the body portion 11, which completes the conical or dome-shaped rotor surface. Also preferably the blades of the rotor are cast integral with an annular base or ring 15 which is then mounted in a peripheral recess 16 in the main casting 11 and secured in place on the rotor body by suitable screws.

The composite rotor preferably, but not necessarily, is

mounted in the side of the tank containing the fibrous material to be treated, as described in U. S. Patent No. 2,654,294, and thus rotates in a vertical plane, with the conical or drome-shaped front face of the rotor facing the interior of the tank. A stationary impingement and attritioning ring 17 surrounds the rotor and is secured to a housing which in turn is mounted to the wall of the tank, a portion of the housing being indicated at 18 in Figure 3 and a portion of the tank being indicated at 18'. This stationary ring 17 has a frusto-conical attritioning surface 19 (see also Figure 2) which is inclined at an angle (preferably of approximately 45) with respect to the plane of rotation of the rotor. The attritioning surface is formed with a series of radially-extending rectangular grooves 20, thus forming radial teeth or attritioning bars between the grooves of the attritioning surface 19.

The rotor blades extend beyond the rotor periphery to the periphery. of the attritioning surface 19 of the stationary ring, and the under sides of the blades lie in a. frusto-conieal surface capable of mating with the attritioning surface 19 of the stationary ring. Means (not shown) is provided for adjusting the rotor shaft 13 to a limited extent in an axial direction and thereby adjusting the clearance between the blades and the attritioning sur face 19 of the stationary ring.

The rotor blades, instead of being all the same size, as has been customary heretofore, are of two sizes, a few of the blades having a greater height than the others. The blades, however, are all of the same width and the spacing is the same between all the blades. rotor shown in Figure l as an example, there are twentyseven blades. Three of these blades, indicated by the reference character 21, are higher than the others or the standard blades 22. The higher blades 21 of the set are spaced equal distances from each other, thus, in this instancebeing spaced 120 apart. The difference in height between the higher blades 21 and the other blades 22 is shown clearly in Figures 3, 4 and 5.

The under sides of all the blades are identical in size and shape. The under side of each blade has an open central channel 23 which extends to the outer end of the blade. Thus all the blades are prong-like, with the under side of each blade having spaced surfaces, and as these prong-like blades move closely over the attritioning surface 19 of the stationary. ring they perform a desired treating action on the pulp fibers of the fibrous material which has been impinged against the stationary ring by the rotation of the rotor.

As apparent from Figure 1, all the rotor blades extend obliquely away from the direction of rotation of the rotor, the direction of rotation being clockwise as viewed in Figure 1 and as indicated by the arrow x. Also the leading face of each blade, that is the lateral side of the blade facing in the direction of rotation of the rotor, extends in a plane sloping obliquely from the plane of Thus, in the rotation of the rotor, while the trailing face or other lateral side of each blade extends in a plane substantially perpendicular to the plane of rotation of the rotor. Thus the leading face 24 (Figures 7 and 9) of each of the higher blades 21, and the leading face 25 (Figures 6 and 8) of each of the standard blades 22 extends in a plane sloping obliquely with respect to the plane of rotation of the rotor while the trailing face 26 of each of the higher blades and the corresponding trailing face 27 of each of the standard blades extends in a plane substantially perpendicular to the plane of rotation of the rotor.

The top ridges 28 of the standard blades 22 (Figures 3 and 4) lie mostly in a frusto-conical surface sloping outwardly and upwardly with respect to the plane of rotation of the rotor, but sloping at a slightly less angle than the under side faces of the blades, as shown in Figure 3, and thus sloping at a slightly less angle than the attritioning surface of the stationary ring. Similarly the top ridges 29 of the higher blades 21 (Figures 3 and 5) lie in a frusto-conical surface which has approximately the same angularity with respect to the plane of rotation of the rotor as the frusto-conical surface containing the top ridges 28 of the standard blades.

The top ridges of all the blades begins at approximately the same radial distance from the axis of rotation of the rotor, starting from points located substantially on a common circle on the face of the rotor. The ridges 28 of the standard blades 22 have a greater extent of curvature at their start from the rotor face, as shown at 28 in Figure 4, than the ridges 29 of the higher blades 21, as'

shown at 29' in Figure 5.

The rotation of the rotor causes the fibrous material, engaged by the rotor blades, to be thrown outwardly from the rotor axis, but this results in a considerable portion of such engaged material being impinged against the frusto-conical surface of the stationary ring. The angularity of this ring surface (preferably approximately 45 with the plane of rotation of the rotor causes the material impinged against this surface to be momentarily restrained, and during this time the material is subjected to an attritioning action between the under sides of the blades and the frusto-conical surface of the stationary ring with its radially extending bars and grooves. After this brief restraint and attritioning action the material is discharged peripherally by the rapidly moving blades for recirculation.

When pieces of material, small enough to pass down between the blades to the frusto-conical surface of the stationary ring, are too large to pass between the under sides of the blades and the ring surface, the obliquelysloping leading faces of the blades urge such pieces upwardly and outwardly over the ring surface without forcing them in between the under sides of the blades and the ring. The impingement of these pieces against the ring surface will nevertheless tend to break them up or reduce their size, so that, after a sufficient amount of recirculation, the fibrous material from such pieces will finally receive the desired attritioning action between the blades and the frusto-conical surface of the stationary ring. Any foreign particles, such as tramp metal, which may inadvertently have been deposited in the tank with the fibrous material, will also be thrown off from the ring surface by the leading faces of the blades, thus reducing to a minimum the damage to the treating machine by such foreign particles.

As previously mentioned, one of the problems encountered with the operation of the pulp shredding and treating machine of U. S. Patent No. 2,654,294 has been the fact that, in many instances, larger slabs or masses of fibrous material, being too large to pass down between the rotor blades to the stationary ring, collect on or over the rotor, impeding the normal passage to the attritioning ring and retarding the proper circulation of material in thrown off from the rotor the tank. However, it has been found that the substitution of the higher blades 21 for somfof the standard blades in the improved rotor prevents such condition developing and that pieces of the fibrous material which are too' large to reach' the attritioning ring at first are subjected to repeated impact by the higher blades with the result that they are -either immediately broken up sufiiciently by the higher :blades to enablelthe :reduced smaller particles to pass down to the ring," or else are by the higher blades and in this way caused to be recirculated until such time as repeated impact by the higher blades will break up these larger pieces sufliciently. his recirculation Ofithelarger pieces, caused by the "higher blades, also has "theadded advantage of increasing the turbulence and circulation of all of the material in the tank and at the same time of heeping the passageways between the blades to the stationary ring open. Furthermore, this desirable increased turbulence and circulation of the material in the tank is attained Without having to increase rotor speed and with only a minimum increase in power required.

Smce spacing between all the blades is the same, and since the higher blades are no wider than the standard blades, the operation of the machine under optimum conditions, in which there would be no pieces of material too large to take the normal prescribed course to the frusto-conical attritioning surface of the stationary ring, is not rendered less efiicient or modified in any way by the presence of-the higher blades. However, since such optimum conditions seldom exist, and since generally there will be some pieces of material at the start of the machine operation which are too large to follow such normal course, the higher blades make it possible for these larger pieces to be controlled and handled, and consequently increase the overall machine.

For the purpose of this description the rotor has been illustrated as equipped with a total of twenty-seven blades, including three higher blades. While rotors with this number and arrangement of blades have proved very satisfactory and efficient, the invention is not to be considered as limited to a rotor having any particular number of blades or any particular number of higher blades. Thus, for example, under some conditions it might be preferred to have four of the higher blades on the rotor, and therefore spaced 90 apart, or more than four, or it might be suflicient to have only two of the higher blades. Similarly, of course, the number, and therefore the spacing, of all the blades on the rotor can be varied to suit diiferent conditions of operation. It is essential, however, in the carrying out of this invention, thatthe number of the higher blades be considerably less than the number of the standard blades on the rotor, that the higher blades be spaced equidistant from each other, and preferably also that the under sides of the higher blades and of the standard blades be identical.

I claim:

1. In a pulp shredding and treating machine of the character described wherein a rotor is surrounded by a stationary ring having a frusto-conical attritioning surface and a plurality of blades on the rotor extend beyond the operating efliciency of the periphery of the rotor over the attritioning surface of the v stationary ring and the under sides of the blades lie in a fmsto-conical surface capable of mating with the attritioning surface of the stationary ring, the improvement in the rotor which includes having a few of said blades made of greater height than the other blades, but with the under sides of said higher blades lying in the same frusto-conical surface as the under sides of said other blades, said higher blades equally spaced from each other, the top edges of said higher blades extending in a frustoconical surface inclined at an angle with the plane of rotation of the rotor and the top edges of all of said blades beginning on said rotor at points located substantially on a common circle concentric with the rotor axis, whereby,

with the rotation of said rotor, said higher blades will encounter larger pieces of the material being treated in -said machine before said-larger pieces reach said other blades on said rotor and thereby-reduce the tendency of said larger pieces to impede the proper functioning of the machine.

2. In apulpshredding and treating machine including a rotor surrounded by a stationary ring having a frustoconical attritioning surface and a plurality of blades on the rotor extending beyond the periphery of the rotor over the attritioning surface of the stationary rin with the under sides .of the blades lying in a frus'to-conica'l surface capable urinatin with the attritioning surface of the stationary ring, the improvement in the rotor which comprises having a fewof said blades made of greater height than the other blades, but with the under sides of said higher blades lying in the same frusto-conical surface as the under sides of said other blades, the under sides of said higher blades being identical in shape and size with the under sides of said other blades, said higher blades equally spaced from each other, the top edges of said other blades extending in a frusto-conical surface inclined at a less angle with the plane of rotation of said rotor than the under sides of said blades, and the top edges of said higher blades extending in a frusto-conical surface inclined at substantially the same angle with said plane of rotation of the rotor as the top edges of said other blades, whereby, with the rotation of said rotor, said higher blades will encounter larger pieces of the material being treated in said machine before said larger pieces reach said other blades on said rotor and thereby reduce the tendency of said larger pieces to impede the proper functioning of the machine.

3. In a pulp shredding and treating machine wherein a rotor is surrounded by a stationary ring having a frustoconical attritioning surface and a plurality of prong-like blades on the rotor extend beyond the rotor periphery over the attritioning surface of the stationary ring and the under sides of the blades lie in a frusto-conical surface capable of mating with the attritioning surface of the stationary ring, the improvement which comprises having a few of said blades made of greater height than the other blades, but with the under sides of said higher blades lying in the same frusto-conical surface as the under sides of said other blades, the under sides of said higher blades being identical in shape and size with the under sides of said other blades, all of said blades being equally spaced on the periphery of said rotor, said higher blades equally spaced from each other, the lateral side of each of said higher blades facing in the direction of rotation of said rotor extending in a plane oblique to the plane of rotation of said rotor, the opposite trailing side of each of said higher blades extending in a plane substantially perpendicular to said plane of rotation, the top edges of said higher blades extending in a frusto-conical surface inclined at an angle with said plane of rotation, and the top edges of all of said blades beginning on said rotor at points located substantially on a common circle concentric with the rotor axis, whereby, with the rotation of said rotor, said higher blades will encounter larger pieces of material being treated in said machine before said larger pieces reach said other blades on said rotor and thereby reduce the tendency of said larger pieces to impede the proper functioning of the machine.

4. In a pulp shredding and treating machine of the character described including a rotor surrounded by a stationary ring having a frusto-conical attritioning surface and a plurality of prong-like blades on the rotor extending beyond the periphery of the rotor over the attritioning surface of the stationary ring with the under sides of the blades lying in a frusto-conical surface capable of mating with the attritioning surface of the stationary ring, the improvement in the rotor which consists in having a few of said blades made of greater height than the other blades, but with the under sides of said higher blades lying 7 in the same frusto-conical surface as the under sides of said other blades, the under sides of said higher blades being identical in shape and size with the under sides of said other blades, all of said blades being equally spaced on the periphery of said rotor, said higher blades equally spaced from each other, the lateral side of each blade 'facing in the direction of rotation of said rotor extending in a plane oblique to the plane of rotation of said rotor, the opposite trailing side of each blade extending in a plane substantially perpendicular to said plane of rotation, the top edges of said other blades extending in a frustoconical surface, and the top edges of said higher blades extending in a frusto-conical surface inclined at approximately the same angle with said plane of rotation as the top edges of said other blades, and the top edges of all of said blades beginning on said rotor at points located substantially on a common circle concentric with the rotor axis, whereby, with the rotation of said rotor, said higher blades will encounter larger pieces of material being treated in said machine before said larger pieces reach said other blades on said rotor and thereby reduce the tendency of said larger pieces to impede the proper functioning of the machine.

References Cited in the file of this patent UNITED STATES PATENTS

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