US3432107A

US3432107A - Pulper impeller vane

Info

Publication number: US3432107A
Application number: US603904A
Authority: US
Inventors: Charles A Johnson
Original assignee: Bolton Emerson SA
Current assignee: Bematec SA; Bolton Emerson Americas Inc
Priority date: 1966-12-22
Filing date: 1966-12-22
Publication date: 1969-03-11
Anticipated expiration: 1986-03-11

Description

March 11, 1969 c. A. JOHNSON PULPER IMPELLER VANE Filed Dec. 22, 1966 INVENTOR. Charles A. Johnson BY PW v-P ATTORNEYS United States Patent Ofice 3,432,107. Patented Mar. 11, 1969 6 Claims This invention relates to a novel and improved disintegrator or pulper of the type used in the paper industry. More particularly, the invention relates to a novel pulping impeller and to novel pulping vanes for mounting thereon.

The type of pulper to which the invention relates may be either a side-rotor pulper or a bottom-rotor pulper a single rotor pulper or a dual rotor pulper.

It has heretofore been proposed, as in US. Patent No. 2,999,650, to Campagnano of Sept. 12, 1961, to provide a composite impeller in which there are a set of curved vanes for creating the usual vortical circulation in the tank, and a second set of spoon shaped blades having upturned terminal tips for creating a secondary vortical circulation. In US. Patent No. 2,996,313 to Hughes of Dec. 27, 1960, two sets of blades are also disclosed, each on a separate impeller, and each having triangularly upturned terminal tips for chewing up the stock. While the use of an abruptly upturned terminal tip on the vanes, disclosed in these patents, may well be useful for attrition purposes as in Hughes, or for creating a multple vortical circulation pattern, as in Campagnano, such a configuration does not solve, the problem of the plugging, matting or stapling ofmaterial on the vanes. It has been found that in all circulating vane structures presently used in waste paper, or broke, pulpers, despite the vortical circulation created by the impeller, the pulper gradually loses efliciency, due to an accumulation of material, especially on the leading edge of the vanes.

Applicants have discovered that a very substantial improvement in fiber stock handling characteristics of a pulper may be achieved by utilization of a pulping impeller comprising a plurality of identical, curved pulping vanes, which include, centrally of their length, an abrupt upward curvature to form an inwardly-facing surface or wall, thereby forming a flow barrier and a zone of turbulence in the outwardly moving stream of stock. This novel design has been found to facilitate the handling of diflicult-to-handle stock including paper waste, and to virtually eliminate plugging and stapling problems over a very wide range of pulping operations. Moreover, when these inwardly-facing walls, or surfaces, which are preferably nearly normal to the plane in which the pulping impeller is operating, are somewhat remote from the impeller circumference, for example, set back at least 20% of the distance from the periphery to the hub of the impeller, an especially beneficial circulating pattern featuring a relatively small vortex of less diameter than the impeller diameter is acheived.

Accordingly, it is an object of the invention to provide a novel pulping apparatus which contributes efiicient and continuous trouble-free operation to pulping operations.

It is another object of the invention to provide a pulp ing impeller which resists plugging, matting or stapling on the impeller vanes.

Another object of the invention is to provide an apparatus for creating sulficient turbulence intermediate of the impeller to lift off adhered material on the vanes without unduly interfering with the normal vortical flow path of the pulper.

Other objects of the invention will be obvious from the claims the description of the drawings, and from the drawings.

In this application and accompanying drawings, a preferred embodiment of the invention has been shown and described and alternatives and modifications thereof have been suggested, but it is to be understood that these are not intended to be exhaustive and that other changes and modifications can be made within the scope of the invention. These suggestions herein are selected and included for purposes of illustration in order that others skilled in the art will more fully understand the invention and the principles thereof and will be enabled to modify it and embody it in variety of forms, each as may be best suited to the condition of a particular case.

FIGURE 1 is a sectional view in elevation of a pulper in which is mounted a pulper impeller according to the invention.

FIGURE 2 is a plan view on line 2-2 FIGURE 1.

FIGURE 3 is a perspective showing part of a pulper rotor of the invention with the novel pulping vane mounted thereon.

FIGURE 4 is a view in elevation of a pulper vane according to the invention.

Referring to FIGURE 1, it is seen that the pulp disintegrator, or pulper, 20, has a pulp container 21 with a fiat, horizontal, central bottom portion 22, an upwardly sloping outer bottom portion 19, and an upstanding cylindrical wall 23. The pulp container 21 is adapted to receive a charge of water and paper stock material such as broke paper, waste paper, virgin lap pulp or the like. An arcuate sump 24 extends around the outer periphery of the container with a screen 25 in the bottom 22 and a drain pipe 26 all in a manner well known to the art for discharging the pulped stock. Impeller 30 is mounted in container 21 just above the bottom 22 to rotate in a horizontal plane on a vertical axis by means of central drive shaft 32. Drive shaft 32 is suitably journalled in bearings 34 mounted in bearing housing 35 fixed below central bottom aperture 36 of container 21. Commercially available O-rings and closure seals are used to prevent leakage in a manner known to the art and unnecessary for description in detail herein.

Impeller 30 includes a plurality of identical blades or pulping vanes 37, each of predetermined length, and having opposite and substantially

parallel side faces

39 and 40. Vanes 37 are spaced on the flat diametrical face 27 of backplate 38 of impeller 30. Each vane 37 comprises an arcuate inner portion 41 which merges with a substantially straight outer portion 42. Arcuate portion 41 rises from proximate the central portion of backplate 38 to a first position centrally of the length of the vane and at about a constant 19 angle. Straight portion 42, however, starting approximately at the said first position at the juncture of

portions

41, 42, rises sharply in rate of angular departure from backplate 38 to form an upwardly curved face which terminates in a vertical wall, or edge face, 43, substantially normal to backplate 38 of impeller 30 and facing inward toward the center of the impeller at a second position centrally of the length of the vane. The upper edge face 44, of straight portion 42, is substantially parallel to backplate 38 of impeller 30 and vane 37 terminates in a downwardly sloping face 46, which extends beyond the edge of backplate 38.

Impeller 30 may include, along the outer periphery thereof, a series of projecting attrition blades 47, spaced around the periphery of the impeller and each at a predetermined angle from a radial line through the blade.

In operation, water and waste paper are supplied to container 21 and impeller 30 is caused to rotate by shaft 32. Pulping vanes 37 provide a recirculating action while attrition members 47 provide a shredding action on the waste paper pulp.

Whether the pulper is a side drive or bottom drive type, the vanes 37 create the usual vortex in which the material is continually moved around the side walls, or up the side Walls, and is then drawn downwardly along the axis of the rotor impeller toward the centre and is then again centrifugally thrown outwardly toward the side walls. This conventional, and Well known, vortical circulation is shown diagrammatically by the hollow headed arrows and continues unchanged in the pulper of this invention, and is called the closed, vortical circulation path.

The dislodging action of the pulping vanes 37 of this invention is of a particularly advantageous nature in that a cylindrical zone of turbulence 49 appears to be formed, of less diameter than that of the closed vortical circulation path. The zone of turbulence is defined by the vertical walls 43 of the rotating vanes 37 which are believed to create a lifting force along the vanes capable of dislodging upwardly or forwardly any material tending to adhere to the leading edges of the blades. In FIGURE 4, the zone of turbulence 49 is shown diagrammatically with solid headed arrows. Stapling, matting and plugging are thus prevented, perhaps also because of the steep accelerating action of the rapidly rotating vertical walls 43 which imparts a high upward velocity to material coming in contact therewith. In a typical pulping operation the impeller will rotate at 400 to 500 r.p.m. At about 490 rpm. the tip would travel about 4,000 feet per minute. At such speeds some types of waste paper, for example a piece of a paper pie plate, may tend to hang up on the leading upper edge 50 of the upper face of one of the pulping vanes 37. This hanging up, or stapling, as it is known to the art, does not occur with the pulping vanes 37, the vertical walls 43, rotating unidirectionally at high speed, constituting identical barriers intermittently moving into and out of the flow path, intermediate of the vanes, to remove any material which might tend to adhere to the vanes.

Although a particular embodiment of the invention has been disclosed above in detail for illustrative purposes, it will be understood that variations or modifications of such disclosure, which lie within the scope of the appended claims are fully contemplated.

What is claimed is:

1. A pulper impeller of the type rotatable by a shaft within a tank for pulping fibrous paper stock material, said impeller comprising:

a backplate, mounted fast on said shaft and having a flat, diametrical face in a single plane normal to the axis of said shaft,

and a plurality of pulping circulation vanes, uniformly spaced around, and projecting axially from, said backplate,

each said vane being substantially arcuate in plan, being of predetermined length, and being of substantially uniformly increasing height from a position proximate the central portion of said backplate outwardly to a first position centrally of the length of said vane,

said vane increasing abruptly and substantially in angle of slope from said first position centrally of said length to a second position centrally of said length to form an inwardly facing wall substantially normal to the plane of said backplate and parallel to the axis of said shaft,

whereby the said inwardly facing walls on said vanes form a rotating barrier to outward vortical flow from said impeller, the resulting turbulent zone preventing plugging, matting, and stapling of material on said vanes.

2. A pulper impeller as defined in claim 1:

wherein each said vane includes parallel, opposite side faces of substantially constant increasing height from said position proximate the central portion of said backplate outwardly to said first position centrally of the length of said vane and includes a uniformly sloped, planar, outer edge,

said outer edge abruptly and substantially increasing in angle of slope from said first position to a second position centrally of the length of said vane to form said wall substantially normal to the plane in which said backplate is rotatable.

3. A pulper impeller as defined in claim 1, wherein:

said wall, substantially normal to the plane in which said backplate is rotatable, is at least about 20% of the distance from the periphery of said plate toward the center of said impeller.

4. A pulper impeller as specified in claim 1, wherein:

said inwardly facing Wall of each said vane is in a plane normal to a radial plane extending through the axis of rotation of said impeller.

5. A pulper impeller as specified in claim 1, plus a plurality of attrition blades spaced around the periphery of said impeller, each projecting slightly beyond said periphery and at a predetermined angle from a radius of said impeller passing therethrough.

6. A circulating vane for use on the impeller of a pulper, said vane comprising:

a body of predetermined length, having a base portion extending from the central portion of said impeller to the periphery thereof and of generally arcuate configuration, said body having opposite, parallel, upstanding, side walls and having an outer face defined between the leading and trailing outer edges of said side walls;

said outer face shoping gradually upwardly and outwardly from the inner end of said body to a position centrally of the length thereof and then turning abruptly and vertically outward to form an upstanding wall facing the axis of said impeller and then turning parallel to said base portion to proximate the periphery of said impeller.

References Cited UNITED STATES PATENTS 2,719,011 9/1955 Bebinger 241-4611 3,017,125 1/1962 Sherman 241-4617 3,054,565 9/1962 Willems 24146.11 3,085,756 4/1963 Danforth 24146.17 3,163,368 12/1964 Johnson 241-4617 LESTER M. SWINGLE, Primary Examiner.

D. G. KELLY, Assistant Examiner.

Claims

1. A PULPER IMPELLER OF THE TYPE ROTATABLE BY A SHAFT WITHIN A TANK FOR PULPING FIBROUS PAPER STOCK MATERIAL, SAID IMPELLER COMPRISING: A BACKPLATE, MOUNTED FAST ON SAID SHAFT AND HAVING A FLAT, DIAMETRICAL FACE IN A SINGLE PLANE NORMAL TO THE AXIS OF SAID SHAFT, AND A PLURALITY OF PULPING CIRCULATION VANES, UNIFORMLY SPACED AROUND, AND PROJECTING AXIALLY FROM, AND BACKPLATE, EACH SAID VANE BEING SUBSTANTIALLY ARCUATE IN PLAN, BEING OF PREDETERMINED LENGTH, AND BEING OF SUBSTANTIALLY UNIFORMLY INCREASING HEIGHT FROM A POSITION PROXIMATE THE CENTRAL PORTION OF SAID BACKPLATE OUTWARDLY TO A FIRST POSITION CENTRALLY OF THE LENGTH OF SAID VANE, SAID VANE INCREASING ABRUPTLY AND SUBSTANTIALLY IN ANGLE OF SLOPE FROM SAID FIRST POSITION CENTRALLY OF SAID LENGTH TO A SECOND POSITION CENTRALLY OF SAID LENGTH FOR FORM AN INWARDLY FACING WALL SUBSTANTIALLY NORMAL TO THE PLANE OF SAID BACKPLATE AND PARALLEL TO THE AXIS OF SIAD SHAFT, WHEREBY THE SAID INWARDLY FACING WALLS ON SAID VANES FORM A ROTATING BARRIER TO OUTWARD VORTICAL FLOW FROM SAID IMPELLER, THE RESULTING TURBULENT ZONE PREVENTING PLUGGING, MATTING, AND STAPLING OF MATERIAL ON SAID VANES.