Paper making and fiber liberation – Apparatus – Digester
Reexamination Certificate
1999-11-15
2001-07-31
Chin, Peter (Department: 1731)
Paper making and fiber liberation
Apparatus
Digester
C162S241000, C162S028000, C162S052000, C366S303000, C366S307000, C366S186000, C366S015000, C366S027000, C366S076800, C366S004000, C222S368000
Reexamination Certificate
active
06267847
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stock preparation system for preparing a fiber suspension for use in a paper-making machine, and, more particularly, to a pulper in such a stock preparation system.
2. Description of the Related Art
A fiber stock preparation system is used to make a fiber suspension from a source of fiber such as wood. The fiber stock preparation system receives the raw source of fiber, breaks the raw source of fiber into individual fibers suspended within a liquid such as water, and separates contaminants from the fiber suspension.
It is known to provide a pulper in a fiber stock preparation system as described above to break down the raw source of fiber into individual fibers. A pulper typically includes a rotatable element therein which imparts mechanical forces to the source of fiber and breaks the source of fiber into individual fibers. The pulped fiber is transported downstream to other mechanical devices within the stock preparation system. For example, the pulped fiber may be further processed within a disperger. A disperger receives the pulped fiber and removes contaminants from the fiber suspension and thoroughly mix chemicals within the fiber suspension. The disperger includes a shaft assembly with a plurality of foils which move in very close proximity relative to a plurality of foils carried by a housing. The tight tolerances within the disperger are intended to process the liquid under relatively high pressure so that the chemicals may be thoroughly mixed and the contaminants removed. To achieve thorough mixing of the chemicals, the dwell time of the fiber suspension within the disperger is relatively long. The disperger has an output which is in the form of an open end of the housing which discharges directly to the ambient environment. Because of the tight tolerances and pressures utilized within the disperger, a high energy input is required to drive a disperger. Moreover, such a disperger has a low throughput rate.
What is needed in the art is a pulper which has a high throughput rate, may be oriented in multiple orientations and requires very little input energy for pulping of the input source of fiber.
SUMMARY OF THE INVENTION
The present invention provides a pulper in a stock preparation system with a drum and a plurality of stationary pulping foils, a shaft assembly having an auger and a plurality of movable pulping foils, and a conical valve positioned with respect to an outlet of the drum and movable in directions toward and away from the outlet to selectively open and close the outlet.
The invention comprises, in one form thereof, a pulper in a stock preparation system. The pulper includes a housing with a fiber inlet, at least one water inlet, at least one outlet and an inner chamber. A plurality of stationary pulping foils are attached to the housing and extend into the inner chamber. A rotatable shaft assembly extends through the inner chamber. The shaft assembly includes a shaft, an auger positioned around the shaft and relative to the fiber inlet and a plurality of movable pulping foils carried by and extending from the shaft. A conical valve is positioned in association with the outlet and is selectively movable to open and close the outlet.
An advantage of the present invention is that a pulper with a simplified construction and high throughput rate is provided.
Another advantage is that the conical valve at the discharge outlet of the drum provides easy regulation of the throughput rate through the pulper.
Yet another advantage is that one or more shaft assemblies with multiple augers and movable pulping foils may be provided in association with a single inlet to increase the throughput rate through the pulper.
REFERENCES:
patent: 3773610 (1973-11-01), Shouvlin
patent: 4121967 (1978-10-01), Reinhall
patent: 5198075 (1993-03-01), De La Bruniere
Doelle Klaus
Matz Robert J.
Chin Peter
Halpern Mark
Taylor & Aust P.C.
Voith Sulzer Paper Technology North America Inc.
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