Claims
- 1. In apparatus for making high strength smooth surfaces paper from stock having a slurry of fibers in a liquid carrier, the combination comprising:
- a headbox having a high consistency stock chamber and means for delivering high consistency fibrous stock to said chamber;
- a slice chamber connected to said headbox and having means downstream defining a slice opening for delivering stock to paper web forming means;
- means in said slice chamber defining a rigid stock flow passageway of substantially uniform depth throughout its length communicating at an upstream end with said stock chamber and communicating at a downstream end with said slice opening, said passageway having:
- a. an upstream straight-on section extending in the direction of the axis of the slice chamber, and at its downstream end, through abrupt right angular turn juncture joining the upstream end of an elongated straight jog section which extends substantially right angularly relative to the axis of the slice chamber
- b. an abrupt downstream end turn acute angle juncture affording a pressure drop area and joining said jog section with a downstreamwardly extending elongated straight slanting passageway section communicating at its downstream end with an abrupt turn obtuse angle juncture with the upstream end of
- c. a sinuous passageway section having a plurality of smoothly curving sinuous loops which diminish progressively in length and height in a downstream direction, and the downstream end of said sinuous section joining
- d. a straight-on flow stabilizing substantial length downstream terminal section of the passageway in which the high consistency stock stream flow is modulated and smoothed
- so that paper making stock flowing through said passageway is vigorously agitated in said jog and slanting sections and in said abrupt turn junctures and has the fibers thereof substantially uniformly distributed and the fiber distribution is then substantially maintained throughout the sinuous and straight-on sections and to the downstream end of said passageway.
- 2. In apparatus according to claim 1, means at the downstream end of said passageway for effecting controlled pressure drop of the high consistency stream on leaving the downstream end of said terminal section of the passageway.
- 3. In apparatus according to claim 2, said means for effecting controlled pressure drop comprising flexible lips which extend downstream from the downstream end of said terminal section of the passageway and are spaced apart greater than the depth of said passageway.
- 4. In apparatus for making a multi-ply smooth surfaced paper web from stock having a slurry of fibers in a liquid carrier, the combination comprising:
- a headbox having a lower wall and an upper wall and including means defining an upper stock chamber and a lower stock chamber for low consistency fibrous stock to form outer surface plies for a finished web;
- said headbox including means defining an intermediate stock chamber between said upper and lower chambers for high consistency fibrous stock for an intermediate ply between said outer plies;
- first and second delivery means connected respectively to said upper and lower chambers for delivering low consistency fibrous stocks for the outer surface plies;
- an intermediate stock delivery means connected to said intermediate chamber for delivering a high consistency stock thereto;
- a slice chamber connected to receive stock from said stock chambers and extending from the headbox and having upper and lower slice walls respectively connected to said upper and lower headbox walls and tapering toward each other leading to a slice opening to discharge onto paper web forming surface means;
- said slice chamber having an upper slice chamber portion and having a lower slice chamber portion respectively connected to receive stock from said upper and lower headbox chambers and directed to discharge from said slice opening onto said forming surface means as separate ply layers to provide upper and lower outer surface plies for the multi-ply paper web;
- means for maintaining fine scale fiber distributing turbulence in the stock which is directed by said upper and lower slice chamber portions to said slice opening;
- a rigid intermediate portion of the slice chamber positioned between said upper and lower slice chamber portions and defined between rigid upper and lower intermediate portion walls which face one another and separate said upper and lower slice chamber portions;
- said intermediate portion walls having cooperating facing undulating surfaces defining a tortuous fiber distributing flow passageway which communicates in high consistency stock receiving relation at its upstream end with said intermediate stock chamber and has its downstream end adjacent to said slice opening for discharging an intermediate ply layer between said low consistency stock outer surface ply layers;
- said passageway including an upstream part comprising a straight-on section having a downstream end abrupt right angular juncture with a right angular elongated straight jog section which has at its downstream end an abrupt acute angle juncture with the upstream end of a downstreamwardly elongated straight slanting section of substantial length, which, in turn, has at its downstream end an abrupt obtuse angle juncture with the upstream end of a sinuous section of substantial length and having a series of smoothly curving sinuous loops which progressively diminish in length and height from said obtuse angle juncture in a downstream direction for maintaining said uniform fiber distribution after the high consistency stock has been subjected to vigorous fiber distributing agitation of the fibers in the stream;
- and a generally straight terminal section of substantial length extending from the downstream end of said sinuous section toward the end of said passageway for modulating and smoothing flow of said intermediate ply layer to its joining with the outer ply layers, so that said outer ply layers on engaging said intermediate ply layer will present substantially smooth outer surfaces for the multi-ply paper web.
- 5. In apparatus for making multi-ply paper web according to claim 4, said downstream end of said passageway terminating short of said slice opening, said means for maintaining fine scale turbulence comprising flexible sheet members in at least one of said upper and lower slice chamber portions and secured at their upstream ends to said headbox and having their downstream ends unattached and terminating downstream relative to the end of said passageway in said rigid intermediate portion, said downstream ends of said members terminating upstream from said slice opening.
- 6. An apparatus for making multi-ply paper web according to claim 4, said modulating and smoothing means comprising flexible lips which extend from the downstream ends of said rigid walls and receive therebetween the high consistency stock stream from the downstream end of said passageway, said lips having their downstream ends upstream adjacent to said slice opening and the lips being spaced apart greater than the rigid wall downstream end of said passageway, for effecting a controlled pressure drop in the stream before it joined as intermediate ply layer with said outer ply layers.
- 7. In apparatus for making multi-ply paper web according to claim 4, said rigid intermediate slice chamber portion being constructed so that said passageway is of substantially uniform depth from the headbox to the downstream end of the rigid intermediate portion walls.
- 8. In apparatus for making multi-ply paper web according to claim 4, said modulating and smoothing means comprising lips which are flexibly connected to the downstream ends of said rigid walls, the downstream ends of said lips being located adjacent to the slice opening, said lips being spaced apart slightly greater than the downstream end of said passageway and being adapted in the presence of equal stock pressure on all faces of the lips to extend in substantially parallel relation.
- 9. In apparatus for making multi-ply paper web according to claim 8, said means for maintaining fine scale turbulence in the stock comprising downstreamwardly extending flexible sheet-like elements anchored at their upstream ends to said headbox and extending generally convergently in said upper and lower slice chamber portions, the downstream ends of said sheet-like elements terminating a substantial distance short of said lips.
- 10. Apparatus according to claim 4, including means for controlling pressure drop of said high consistency stock at the discharge end of said straight terminal section.
PRIOR APPLICATIONS
This application is a continuation-in-part of Ser. No. 195,593, filed Oct. 9, 1980, now abandoned which is a continuation of Ser. No. 029,543, filed Apr. 12, 1979, now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
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446331 |
Jan 1948 |
CAX |
Continuations (1)
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Number |
Date |
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29543 |
Apr 1979 |
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Continuation in Parts (1)
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195593 |
Oct 1980 |
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