Paper making and fiber liberation – Processes and products – Running or indefinite length work forming and/or treating...
Reexamination Certificate
1999-05-28
2001-02-20
Silverman, Stanley S. (Department: 1731)
Paper making and fiber liberation
Processes and products
Running or indefinite length work forming and/or treating...
C162S206000, C162S199000, C162S193000, C162S289000, C162S290000, C162SDIG006
Reexamination Certificate
active
06190505
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. § 119 of German Patent Application No. 198 24 170.4, filed on May 29, 1998, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an apparatus and method for moistening a material web, and more particularly, to an apparatus for moistening a paper or cardboard web.
2. Discussion of Background Information
In paper making machines, problems frequently arise at the marginal regions (i.e., the edge regions) of a paper web. Such problems can arise in the headbox, where the fibers in these marginal regions are arranged in both the longitudinal direction (as in the center of the web), and in the width direction. The web tends to dry out more severely at the margins (i.e., the edges) of the web. At the surface of a drying cylinder, the region adjacent the web is hotter, because less heat dissipates from this region. Consequently, the edges of the web dry out more rapidly. This drying is also exacerbated by the fact that the marginal regions of the web are closest to the dry atmosphere of the paper-making facility and thus also give off moisture by convection.
Attempts to counteract this drying have been made by designing relatively complicated dryer cylinders, which apply heat to the edge regions of the web. Overheating at the edge regions of the web, however, leads to shrinkage and embrittlement in these marginal regions, which is disadvantageous for subsequent satinizing processes (i.e., the production of smoothness and/or gloss). Shrinkages lead to increases of density and thickness of the web edges.
Also, attempts to counteract these increases in density and thickness by applying less material at the headbox have led to undesirable results. Moreover, installation of a system of this kind is not possible for older facilities. The embrittlement no longer permits any reasonable smoothing in the calender, because the compressibility of the web is greatly restricted. The difference in alignment of the fibers at the web exacerbates this problem.
In German Patent Application No. DE 37 41 680, a related art moistening device is described, which extends over the full width of the web, with different transverse moisture profiles being selectable through a plurality of setting members.
SUMMARY OF THE INVENTION
The present invention provides an apparatus and method for moistening a material web. The apparatus of the invention includes a moistening device adapted to cover the marginal regions of the material web, so that only the marginal regions are moistened. The moistening device may additionally cover the upper and lower surfaces of the web, and may be further adapted to moisten the marginal regions of the material web on both upper and lower surfaces of the material web.
According to a feature of the invention, the moistening device may include at least two moisteners disposed in operative relation to a respective edge of the material web. Further, at least one of the moisteners may have a generally “U”-shaped cross section. The moistener may also be adapted to engage about a marginal region of the material web and cover the upper and lower surfaces of a marginal region of the material web. Also, the marginal region covered may be between approximately 10 cm and 15 cm, in a width direction of the web. Additionally, the size of the covered regions on the upper and lower surfaces are approximately equal to one another.
According to another feature of the invention, the moistener may have a generally U-shaped cross section, with the two arms of the moistening device being pivotable relative to one another, so that the moistener is adjustable between an open position and a closed position.
The moistening device may be a vapor moistener which may or may not be heated. If a heated vapor moistener is used, the heated vapor moistener may have a double sleeve. A condensation discharge outlet and/or a suction device may also be provided. Further, an elongated moistener extending the direction of web travel may also be used. The length of the elongated moistener may be such that the web dwells within the moistener for at least approximately 0.3 ms, at a predetermined running speed. Additionally, the elongated moistener may be a vapor moistener.
The method of the present invention includes covering the marginal regions of the material web with a moistening apparatus, and moistening only the marginal regions of the material web covered by the moistening apparatus. The method may further include covering, with the moistening apparatus, the upper and lower surfaces of the web, and moistening the marginal regions of the material web on both upper and lower surfaces of the material web. Further, both marginal regions of the web may be moistened.
According to a certain feature of the invention, the moistening apparatus may have a generally “U”-shaped cross section, the method may further include engaging the moistening apparatus about a marginal region of the material web, and covering the upper and lower surfaces of a marginal region of the material web.
According to a feature of the invention, the method may further include pivoting the two arms of the “U”-shaped moistening apparatus relative to one another, between an open position and a closed position. The pivoting “U”-shaped moistening apparatus may further be a vapor moistener which may or may not be heated, and may or may not have a double sleeve.
The present invention provides a moistening device which moistens and conditions a material web, e.g., a paper or cardboard web, so that the web margins can be easily satinized.
The moistening apparatus only covers the edge regions of the material web so that only moistening of these marginal regions takes place.
The moistening apparatus of the invention can be used in conjunction with a calender or the like. Smoothness and an ideal gloss is achievable through the invention, especially for the edges of the material web. Thus, an undesired drop in the moisture content, and an undesired increase in thickness at the edge is counteracted in a simple and reliable manner.
In a certain feature of the moistening apparatus of the invention, the marginal regions of the material web are each covered by the apparatus on upper and lower web surfaces, so that in these marginal regions, two-sided moistening (i.e., upper and lower surface moistening) of the material web takes place.
The moistening apparatus may also include at least two moisteners, each associated with a respective marginal region of the material web.
It is also advantageous if at least one moistener has a generally “U”-shaped cross section (“U” shaped meaning: having two generally parallel arms connected at one end by a member extending between the parallel arms), thereby enabling the moistener to engage about the marginal web region and thus cover both surfaces. The moistener covers approximately 10 to 15 cm of the web in the width direction of the web. When using a U-shaped moistener, the covered regions of the two surfaces of the web are approximately the same size.
In a certain feature of the moistening apparatus of the invention, at least one moistener having a U-shaped cross-section is provided, with the two arms of the “U” portion of the moistener being pivotable relative to one another, so that the moistener is adjustable between an open position and a closed operating position, the open position serving for the draw-in of the web.
At least one moistener of a plurality of moisteners may be provided as a vapor moistener, thereby enabling simultaneous heating of the respective material web.
It is also advantageous if at least one heated vapor moistener of a plurality of moisteners is provided, preferably with a double sleeve (i.e. the sleeve having both an inner wall and an outer wall). The intermediate space between the walls of the sleeve forms a vapor blowing chamber. This chamber can be fed with hot steam, so that the walls of the vapor ch
Fortuna Jos'e A.
Greenblum & Bernstein P.L.C.
Silverman Stanley S.
Voith Sulzer Papiertechnik Patant GmbH
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