US3314617A

US3314617A - Pulper defibering means

Info

Publication number: US3314617A
Application number: US340864A
Authority: US
Inventors: Richard J Sargood
Original assignee: Noble and Wood Machine Co
Current assignee: Noble and Wood Machine Co
Priority date: 1964-01-29
Filing date: 1964-01-29
Publication date: 1967-04-18
Anticipated expiration: 1984-04-18

Description

April 1967 R. J. SARGOOD 3,314,6fl7

PULPER DEFI BERING MEANS Filed Jan. 29, 1964 5 Shedsheet 1 @l I l ,O\ I I y I '2 FIG! H .4 16

' l8 I I r I- i 1 22 2O. m

FIGZ l6 I NVEN TOR.

RICHARD J. SARGOOD BY ATTORNEYS April 18, 19s? PULPER DEFIBERING MEANS Filed Jan. 29, 1964 I N VEN TOR.

RICHARD J. SARGOOD F168 BY ATTURN EYS R. J. SARGOOD 3,314,61 7

s Sheets-Sheet 2 April 18, 1967 R. J. SARGOOD 3,314,617

PULPER DEFIBERING MEANS Filed Jan. 29, 1964 3 Sheets-Sheet 5 FIGIZ I N VEN TOR.

RICHARD J. SARGOOD BY ATTORNEYS United States Patent 3,314,617 PULPER DEFIBERIN G MEANS Richard .I. Sargood, Hoosick Falis, N.Y assignor to The Noble 8: Wood Machine (10., Hoosicir Falls, N.Y., a corporation of New York Filed Jan. 29, 1964, Ser. No. 340,864 2 Claims. (Cl. 241-260) This invention relates to machinery for pulping paper stock and more particularly to improved defibering means mounted on rotor and stator elements of a pulper. A pulping machine of this class is described in W. C. Tomlinsons pending application, Ser. No. 73,671, filed December 5, 1960, now abandoned.

With the arrangement shown in the above said pending application, a combined pulping and defibering action is obtained in which the stock is circulated in the pulping tank, subjected to pulping blade action, and withdrawn from the tank through an annular outlet orifice in the tank bottom between the rotor and stator elements of the pulper. In this annular orifice, opposed defibering teeth or equivalent defibering elements additionally defi'ber the stock as it passes therethrough.

The significant features of the prior constructions, as they relate to the present invention, principally concern the type of defibering action taking place in the outlet orifice and the effect of this action in terms of dulling and eroding wear on the defibering elements. It will be understood that the opposed defibering teeth in the annular orifice are not spaced closely together as in the typical jordans, beaters or disc refiners of the prior art, but instead are spaced apart so that the defibering action takes place primarily on the larger stock particles. Of course, the rapidly fluctuating pressure waves created by the teeth of the rotor in moving past the opposed teeth of the stator, despite the spacing therebetween, cause hydraulic shear which acts to some extent on all stock particles in the orifice. With the arrangement and spacing shown, however, the direct, cutting type of contact of a typical refiner takes place only when relatively large particles enter the orifice. These factors are highly significant in the context of the present invention because they determine the type of wearing or eroding action on the teeth. With the arragement shown, the teeth Wear primarily on their leading edges and from the top down. Thus, after a period of extended use, the entry to the annular orifice becomes slightly widened, and the leading edges of the opposed teeth become rounded off.

The present invention has as a primary object the provision of means for extending the useful life of the defibering elements in the annular orifice.

In the accomplishment of this object in a preferred embodiment of my invention, I provide a plurality of removable and reversible defibering teeth segments for mounting on the rotor and stator in the annular orifice. These segments are symmetrically constructed with relation to their mounting means and their Working surfaces so that they can be easily removed, turned upside down, and remounted.

Accordingly, it is a feature of my invention that, once the teeth have become worn in their upper portions and along their leading edges, the segments can be removed and turned over. This action causes the relatively sharp, previously trailing edges, to become the leading edges, and the relatively unworn, previously lower teeth portions to become the upper portions.

It is a further feature of my invention that the relatively mild defibering action in the orifice permits the teeth segments to be secured by standard machine screws without the requirement of wooden spacers, retaining bands or the like, which are required in jordans and 3,314,617 Patented Apr. 18, 1967 heaters in which the refining action creates far more stress and strain.

Other objects and advantages of the invention will become apparent from a study of the accompanying drawings and descriptive matter in which is illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a front elevation of a corporating the invention;

FIG. 2 is a view in perspective of the rotor element of the pulper showing the teeth segments mounted on the periphery thereof;

FIG. 3 is a view in perspective of the stator element showing the teeth segments mounted on the inner circumference thereof:

FIG. 4 is a view in perspective of the rotor and stator elements in assembly with the teeth segments defining an annular outlet orifice therebetween;

FIGv 5 is an elevational View in section showing the mounting of the teeth segment assembly on the rotor and stator elements;

FIG. 6 is a fragmentary plan view of the rotor and stator elements showing the spacing between the opposed teeth segments;

FIG. 7 is a fragmentary front elevation of the teeth segment which is mounted on the rotor element;

FIG. 8 is a fragmentary front elevation of the teeth segment which is mounted on the stator element;

FIG. 9 is a view in perspective of the teeth segment of FIG. 7;

FIG. 10 is a view in perspective of the segment holder on which the teeth segment of FIG. 9 is directly mounted;

FIG. 11 is an exploded elevational View in section of a portion of the rotor element, the segment holder and the teeth segment;

FIG. 12 is a diagrammatic plan view of a small portion of the teeth segment showing by dotted lines the wear which occurs on the leading edges of the teeth; and

FIG. 13 is an elevational view in section of a portion of the rotor element, the segment holder and the teeth segment, showing by a dotted line the wear on the teeth segment which occurs from the top down.

Referring now more particularly to the drawings, FIG. 1 shows the pulper, generally designated as 10, having a tank 12 preferably made from mild steel, stainless steel, cast iron or tile. The tank has a generally horizontal bottom wall 14 in the center of which a circular rotor element 16 is mounted for rotation. Rotor element 16 is fixed to a shaft 18 which is supported in suitable bearings 20. The shaft 18 and associated rotor element 16 are driven by an electric motor and belt drive system indicated generally at 22.

Mounted on the rotor element 16, and extending tangentially from the shaft 18 are a multiplicity of impeller blades 24, usually six in number. Rapid rotation of the rotor element 16 and its impeller blades 24 causes previmove violently within causes the larger particles of stock to break down. Simultaneously, forces are pulping machine into size, and thereafter fall back for further pulping.

The smaller pieces of stock, which comprise the more finished pulp, are not as easily caught up in the vortex field and tend to flow radially from the rotor center. In order to assist this tendency,-a plurality of lateral ejector blades 26 having a right-angled shape are mounted verrotor element coaxial with the shaft 18.

In operation, rotor element 16, impeller blades 24 and ejector blades 26 cooperate to throw the larger stock upward in the tank and to push the more finished pulp radially along the tank bottom 14.

In order to withdraw the more finished pulp from the pulper before it is again intermixed with the larger pieces of stock, an annular outlet orifice, indicated generally at 28, is provided between rotor element 16 and tank bottom wall 14. The annular outlet orifice 28 is created by constructing the bottom wall 14 with an inner circumference of greater radius than that of the outer circumference of rotor element 16. Thus, when the rotor element 16 is in assembly, an annular outlet orifice will be formed between rotor element 16 and tank bottom wall 14. The more finished pulp not only falls into this annular outlet orifice 28 as it passes radially over the rotor element 16, but is also drawn into the orifice by suction forces created by the discharge pump and by the rotation of the rotor element \16 in close proximity to the bottom wall 14.

The facing peripheries of the rotor and stator elements have mounted thereon defi'bering means including a plurality of defibering teeth segments 30. The interaction of these teeth segments reduces the larger particles of pulp stock to the desired size as they pass through the annular orifice 23. It will be seen in FIGS. 2 and 3 that the rot-or element 16 and the stator element 14 each have eight teeth segments mounted on their facing periphcries. One difference between the teeth segments 30 is that the segments mounted on the rotor element have a convex shape whereas the segments mounted on the stator element have a concave shape. Another difference is the segment tooth angle. FIG. 7 shows the tooth angle of the rotor-mounted segment to be approximately 4 from the vertical. FIG. 8 shows the tooth angle of the statorrnounted segment to be vertical. This tooth angle combination has proven to be quite satisfactory for defibering purposes although the invention is not limited thereto. Except for the oppositely curved shapes and the differing teeth angles, the teeth segments 30 are identical. Therefore, the teeth segments mounted on r-otor element 16 will be described in detail, but it will be understood that the stator-mounted segments are essentially similar.

In the preferred embodiment, a teeth segment assembly is composed of a teeth segment 30 shown in FIG. 9, and a segment holder 32 shown in FIG. 10. The teeth segment is attached to the segment holder which is itself attached to the rotor element periphery. Preferably, eight teeth segment assemblies are mounted around the rotor. It will be seen in the exploded view of FIG. 11 that segment holder 32 has a right angled configuration with an upper horizontal portion 34 and a vertical portion 36. The segment holder is threadably secured to rotor element 16 by bolts 38, usually three in number, which are flush fitted into the upper surface of horizontal portion 34'.

A lip 42 is formed at the lower edge of the front surface 44 of segment holder 32. Lip 42 has an upper lip surface 46. Threaded screw receiving bores 48, usually four in number, are formed in the vertical portion 36. Each bore 48 is precisely located halfway between upper :surface 40 of horizontal portion 34 and upper lip surface '46. That is, a horizontal plane passing through the axes of bores 4t} would precisely divide or bisect the front surface 44 of segment holder 32 into two equal areas having equal vertical dimensions.

Each teeth segment 30 has substantially vertical teeth 59, milled in rib-like fashion, which extend from the upper surface 52 to the lower surface 54 of the segment. Other tooth shapes may alternatively be employed. A teeth bed 56 forms the integral backing or foundation for teeth and has a rear curved surface 58. Rear surface 58 of teeth segment 30 and front surface 48 of the segment holder 32 are mirror images which are shaped to fit closely together. countersunk bores 60 are formed through teeth bed 56 in alignment with screw receiving bores 48. Machine screws 62, preferably made from stainless steel, threadably secure teeth segment 30 to segment holder 32. Upper lip surface 46 of lip 42 abuts lower surface 54 of segment 30 and gives added vertical support and stability to the segment. It will be seen in FIG. 5 that the segment holder mounted on the rotor element 16 has a slightly different construction from that of the segment holder mounted on the stator element in that the stator segment holder has no lip 42 but rather has a lower surface 64 formed flush with lower surface 54 of teeth segment 35 The segment support provided by the lip of the rotor-mounted segment holder is instead provided by rim 66 of the stator element. This difference is merely a matter of design choice in the illustrated preferred embodiment and is not critical to the functioning of the invention.

It will now be appreciated that teeth segment 30 is constructed so that its teeth 50 and mounting bores 60 are symmerically located with respect to a horizontal plane bisecting the teeth segment. That is, revolving the teeth segment about an axis normal to a central point on segment rear surface 58 would not change the relative location of the teeth 50 and the bores 60.

This symmetrical construction permits the teeth segments to be used on the pulper for a substantially longer time period of use because after the segments have become worn, they can be detached, flipped over, reattached and used further. To be more specific, wear on the teeth segments occurs in two areas. FIG. 12 shows a teeth segment 30 which, when mounted on rotor element 16, is revolved in a counter-clockwise direction (i.e. to the left). The leading edges of each tooth 50 become worn as illustrated by the dotted lines. FIG. 13 shows an elevation of FIG. 12 and illustrates the teeth wear which occurs from the top down. The combination of teeth wear on the leading edges and from the top down eventually permits larger stock particles to pass through the enlarged :annular orifice without being sufficiently defibered or without being properly defibered. Eitherresult is undesirable.

By constructing the segments in the described sym- 'metrical fashion, the segments, when worn, can be detached, flipped over and remounted whereby the still sharp previously trailing teeth edges become the leading edges and the still unworn previously bottom teeth portions become the top portions.

In operation, after the teeth segments have become worn as described, the segment holders 32 are detached from rotor element 16 and stator element 14 by unbolting bolts 38 and lifting the segment holders and their associated teeth segments 30 from the rotor and stator. The teeth segments 30 are then easily detached from the segment holders 32 by removing screws 62 with a screwdriver or an Allen wrench. The teeth segments 30 are then flipped over so that upper surface 52 is repositioned as lower surface 54 after which the teeth segments are reattached by screws 62 to the segment holders 32. The segment holders are then rebolted to rotor element 16 and stator element 14, placing the pulper in assembled condition for further pulping.

This interchange of position should, under usual pulping conditions, result in an extension in the time period of teeth segment use of approximately 50-70% which obviously constitutes a considerable financial savings.

Obviously, many modifications and variations of the present invention are possible in light of the above teach ings. Therefore, it is to be understood that the invention is not limited in its application to the construction and arrangement of parts specifically described or illustrated, but is to be limited only by the spirit of the invention and the scope of the appended claims.

I claim:

1. In a pulper of the type having a tank with a bottom wall stator, vertical stator walls forming a central circular opening in said bottom wall stator, a rotor mounted for rotation within said central opening, blades mounted on said rotor for pulping the stock, the periphery of said rotor and said vertical stator Walls defining between them an annular outlet orifice through which the .pul-ped stock is withdrawn, the improvement therein comprising; a plurality of cooperating opposed defibering teeth segments having substantially vertical ribs formed therein and walls forming horizontal mounting holes, said teeth segments detachably mounted on said rotor and said stator for defibering oversized particles of stock, said ribs and hole walls of said teeth segments being shaped and located symmetrical to an imaginary plane horizontally bisecting said teeth segments whereby after extensive use has worn said teeth segment ribs, said teeth segments are detached, radially revolved 180, and reattached to permit further use.

2. In a pulper of the type having a tank with a bottom wall stator, vertical stator walls forming a central circular opening in said bottom wall stator, a rotor mounted for rotation within said central opening, blades mounted on said rotor for pulping the stock, the periphery of said rotor and said vertical stator Walls defining between them an annular outlet orifice through which the pulped stock is withdrawn, the improvement therein comprising; a plurality of cooperating opposed defibering teeth segments having substantially vertical ribs formed therein and walls forming horizontal mounting holes; a plurality of segment holders on which said teeth segments are detachably mounted, said segment holders mounted on the periphery of said rotor and the inner circumference of said stator, said teeth segment ribs and mounting hole Walls symmetrically formed and located with relation to a horizontal plane bisecting each said teeth segment whereby after extensive use has worn said teeth segment ribs, said teeth segments can be detached from said segment holders, revolved about an axis normal to the segment teeth face, and reattached to said segment holders to provide for a subsequent period of teeth segment use.

References Cited by the Examiner UNITED STATES PATENTS 1,794,972 3/1931 Mayer 241260 X 2,369,312 2/1945 Porteous 146l84 X 2,484,509 10/1949 Hopkins 241-257 X 2,577,716 12/1951 Shelton 241260 X 2,645,982 7/1953 CoWles 241-257 2,838,981 6/1958 Dent 241257 X 3,009,659 11/1961 Jones 241260 X WILLIAM W. DYER, 111., Primary Examiner. ROBERT C. RIORDON, Examiner. H. F. PEPPER, Assistant Examiner.

Claims

2. IN A PULPER OF THE TYPE HAVING A TANK WITH A BOTTOM WALL STATOR, VERTICAL STATOR WALLS FORMING A CENTRAL CIRCULAR OPENING IN SAID BOTTOM WALL STATOR, A ROTOR MOUNTED FOR ROTATION WITHIN SAID CENTRAL OPENING, BLADES MOUNTED ON SAID ROTOR FOR PULPING THE STOCK, THE PERIPHERY OF SAID ROTOR AND SAID VERTICAL STATOR WALLS DEFINING BETWEEN THEM AN ANNULAR OUTLET ORIFICE THROUGH WHICH THE PULPED STOCK IS WITHDRAWN, THE IMPROVEMENT THEREIN COMPRISING; A PLURALITY OF COOPERATING OPPOSED DEFIBERING TEETH SEGMENTS HAVING SUBSTANTIALLY VERTICAL RIBS FORMED THEREIN AND WALLS FORMING HORIZONTAL MOUNTING HOLES; A PLURALITY OF SEGMENT HOLDERS ON WHICH SAID TEETH SEGMENTS ARE DETACHABLY MOUNTED, SAID SEGMENT HOLDERS MOUNTED ON THE PERIPHERY OF SAID ROTOR AND THE INNER CIRCUMFERENCE OF SAID STATOR, SAID TEETH SEGMENT RIBS AND MOUNTING HOLE WALLS SYMMETRICALLY FORMED AND LOCATED WITH RELATION TO A HORIZONTAL PLANE BISECTING EACH SAID TEETH SEGMENT WHEREBY AFTER EXTENSIVE USE HAS WORN SAID TEETH SEGMENT RIBS, SAID TEETH SEGMENTS CAN BE DETACHED FROM SAID SEGMENT HOLDERS, REVOLVED 180* ABOUT AN AXIS NORMAL TO THE SEGMENT TEETH FACE, AND REATTACHED TO SAID SEGMENT HOLDERS TO PROVIDE FOR A SUBSEQUENT PERIOD OF TEETH SEGMENT USE.