Paper making and fiber liberation – Apparatus – Apparatus repair – cleaning or conditioning
Reexamination Certificate
1999-10-22
2001-10-09
Chin, Peter (Department: 1731)
Paper making and fiber liberation
Apparatus
Apparatus repair, cleaning or conditioning
C162S281000, C015S256510, C015S256530
Reexamination Certificate
active
06299732
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a doctor beam coupled with a roll or cylinder in a paper, and, more particularly, to a doctor beam having a novel cross section construction
BACKGROUND OF THE INVENTION
Paper machines and board machines employ rollers and cylinders over which the web passes during operation of the machine. In order to operate efficiently these roller must remain free from debris. Doctor devices, a.k.a. doctors, are typically employed to clean any debris that may become lodged to the rollers or cylinders. Doctors include a blade which is pressed against the roller or cylinder which serves to scrape and remove debris therefrom.
Typically, doctors are secured to a corresponding roller by a doctor beam which consists of a steel beam having a triangular cross section. These beams are typically large, bulky structures requiring a great deal of space. As a consequence, conventional beams are heavy and consume large amounts of space in a paper or board machine which that may include many rollers and doctors. This necessitates large factories, resuming in increased manufacturing costs.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved doctor beam for securing a doctor to a roll or cylinder of a paper machine.
It is another object of the present invention to provide an improved doctor beam structure which overcomes the disadvantages and shortcomings of the prior art.
It is a further object of the present invention to provide a doctor beam structure which consumes less space than conventional and thereby reduces associated manufacturing costs.
In accordance with the objects of the invention, a doctor beam is provided having a cross-section with a triangular point structure, each of the points of the triangular point structure being interconnected by curved face portions. Thus, the doctor beam according to the present invention includes concave walls. The curvature of the walls is selected according to the curvature of the adjacent roll or cylinder face to be maintained by the doctor. This enables the doctor beam to consume less space than conventional doctor beans as the doctor beam in accordance with the invention may be placed in close proximity to the roll or cylinder without interfering with the same. This feature is particularly advantageous in high speed modem paper or board machines which employ multiple rolls arranged in side by side relationship. In such conditions, conventional rolls can not be employed because that can not be accommodated within the interstitial spaces between rolls.
Thus, the doctor beam structure according to the present invention bas at least one face portion having a curved shape, the curvature of the face substantially corresponding to the curvature of the face of the roll mantle of the adjacent roll. As several of the faces of the doctor beam may be curved in this fashion, the doctor beam is particularly suitable for placement in a dryer section of a paper or board machine between two adjacent cylinders, where space is often too confined for a beam of conventional construction.
The invention will be described in detail with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying drawing. However, the invention is not confined to the illustrated embodiments alone.
REFERENCES:
patent: 5356519 (1994-10-01), Grabscheid et al.
patent: 6036818 (2000-03-01), Odmark
patent: 40 25 106-A1 (1992-02-01), None
Chin Peter
Hug Eric
Steinberg & Raskin, P.C.
Valmet Corporation
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