Solid material comminution or disintegration – Apparatus – Including means applying fluid to material
Reexamination Certificate
1999-12-07
2001-05-22
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Apparatus
Including means applying fluid to material
C241S046170, C241S069000
Reexamination Certificate
active
06234415
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a pulping apparatus.
Such pulping apparatus that include a rotor which is mounted adjacent to a perforated screening plate and which includes helical blades or vanes and whose outer end decreases in diameter are adapted to operate at high pulp concentrations and low apparatus power inputs. In the case of known pulping apparatus, the consistency of the pulps may vary between 3-10% or more, depending on the material concerned and also depending on whether the pulping apparatus operates continuously or batch-wise.
Paper and pulp stock are essentially pulped by the internal friction generated in the pulp flow at high concentrations. It is therefore essential to provide effective circulation even at high concentrations.
The spacing between rotor and screening plate may be about 1 mm. In the case of paper qualities that are very difficult to pulp, the pulper may include a bedplate mounted around the periphery of the rotor. The spacing between rotor and bedplate may also be about 1 mm.
Pulpers that include screening plates may be constructed as S-type units and may include generally horizontally or vertically aligned rotors.
BACKGROUND OF THE INVENTION
SE-C 189584 (Grubbens & Co) describes a known pulper of the aforesaid kind.
U.S. Pat. No. 4,607,802 (Lamort) describes a similar pulper where the rotor shaft carries helical vanes that extend radially from the attachment part of said shaft.
EP-A2 0117716 (The Black Clawson company) describes a pulper in which the end of the rotor has a conically narrowing part at the attachment part of said rotor.
DE-C 3 149 135 (Sulzer-Escher-Wyss) describes a pulper whose rotor has outwardly projecting arms that move along the screening plate so as to keep the plate clean.
GB-A 2 113 570 (Beloit) describes a pulper whose rotor is provided with detachable defibration plates that move over a screening plate.
OBJECTS OF THE INVENTION
The object of the invention is to provide for use with pulping apparatus a rotor that will function more effectively than those rotors known hitherto and that will pulp effectively paper qualities that are not readily pulped, such as pulp that contains large quantities of recycled paper in high concentrations, and wet-strong paper qualities respectively, and which will generate a larger pulp flow across the screening plate than earlier known rotors.
SUMMARY OF THE INVENTION
These and other objects of the invention are achieved with an inventive pulper of the kind described above and having the characteristic features set forth.
The pressure-generating and subpressure-generating element provided at the end of the rotator located adjacent the screening plate subjects the pulp to an intensive alternating action. The rotor will thereby pulp not-readily pulped paper qualities more quickly than the rotors of hitherto known pulpers. The inventive rotor is thus able to pulp successfully even wet-strong qualities of high concentration. The inventive rotor also enables higher pulp concentrations to pass through the holes in the screening plate and therewith permit a greater flow of pulp to pass across the screening plate than was hitherto considered possible.
The rotor also facilitates a pumping effect, since it normally generates an overpressure on the screening side of the plate.
As a result of the hydrodynamic design of the rotor and the pressure and subpressure generating element, the pulp is subjected to an alternating action as the rotor rotates, with the wing-profile shape of said element counteracting plugging of the holes in the screening plate, since the holes are throughpassed by pulp stock in both directions.
This action will be most pronounced when said element has the form of a radially and outwardly projecting shoulder-like element that has a generally flat leading surface in the direction of rotation of the rotor and that is inclined relative to the screening plate.
The surface will normally be inclined at an angle that varies between 55° and 85°. The best effect is normally obtained with an angle of about 75°.
The leading surface of said element is suitably provided with a hard coating, for instance a coating of stellite.
The pressure-generating and subpressure-generating element may be formed integrally with the rotor, wherewith those parts of the rotor that are particularly subjected to wear are provided with a coating of the aforesaid kind.
According to the invention, should the element become worn, any worn part can be repaired by machining or grinding said part and thereafter fitting a new part, e.g. screwing-on a new part, which will also be conveniently provided with a covering of the aforesaid kind and which, in turn, can be replaced when it becomes worn. This separate part may be both reversible and replaceable in order to enhance its use possibilities.
It also lies within the scope of the invention to provide the pressure-generating and subpressure-generating element with a detachable and replaceable part initially, optionally a reversible wear part of the aforesaid nature.
The inventive rotor may also be adapted to co-act with a bedplate on the screening plate.
Further characteristic features of an inventive pulper and advantages afforded thereby will be evident from the following description of a preferred embodiment of the invention, made with reference to the accompanying drawings.
REFERENCES:
patent: 3163368 (1964-12-01), Johnson
patent: 4535943 (1985-08-01), Couture
patent: 4607802 (1986-08-01), Lamort
patent: 3149135 (1983-06-01), None
patent: 117 716 (1984-09-01), None
patent: 2 113 570 (1983-08-01), None
patent: 189 584 (1964-05-01), None
Cellwood Machinery AB
Rosenbaum Mark
Sughrue Mion Zinn Macpeak & Seas, PLLC
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