US 4,906,336 AGranted

Headbox device for a papermaking machine

AssigneeSulzer-Escher Wyss GmbH

InventorsElmer Weisshuhn, Herbert Holik

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Abstract

A fiber stock suspension is directed from a guide device through the nozzle chamber of the headbox device and out of the slice opening thereof onto a papermaking machine. This nozzle chamber comprises at least two zones or sections. The first zone subsequent to the guide device possesses a relatively low convergence angle or low angle of wall inclination of the headbox device relative to the direction of flow of the fiber stock suspension. The other or second zone is positioned prior to or immediately upstream of the slice opening and possesses a substantially greater convergence angle or angle of wall inclination. In the first zone subsequent to the guide device, an improved flow stabilization or quieting of the flow of the fiber stock suspension occurs after the deflection of the fiber stock suspension and the creation of turbulence by the guide device. In the second zone prior to the slice opening the fiber stock suspension is strongly accelerated. This results in an improved quality of the formation of the paper web and the longitudinal and transverse strength of such paper web which is formed in the papermaking machine.

Claims9

Dependent claims

A headbox device for a papermaking machine and having a predetermined direction of flow for a fiber stock suspension passing through the headbox device, comprising:

a distribution box;
a nozzle chamber;
a guide device for conducting the fiber stock suspension in said predetermined direction of flow and serving for distributing the fiber stock suspension across the width of the papermaking machine;
said guide device being located subsequent to said distribution box as seen in said predetermined direction of flow of the fiber stock suspension;
said guide device flow communicating with said nozzle chamber;
said nozzle chamber comprising two lip members defining a slice opening leading to the papermaking machine;
at least one of said two lip members of said nozzle chamber comprising at least two sections with substantially different convergence angles relative to said predetermined direction of flow of the fiber stock suspension;
at least one section of said at least two sections being connected directly subsequently to said guide device and having a first convergence angle of said substantially different convergence angles;
said at least one section of said one lip member defining a quieting zone for substantially equalizing flow velocities of the fiber stock suspension;
at least one further section of said at least two sections lying directly prior to said slice opening of said nozzle chamber and having a second convergence angle of said substantially different convergence angles;
said at least one further section defining an acceleration zone for abruptly accelerating the fiber stock suspension;
said at least one section having a length which is a multiple of the length of said at least one further section;
said first convergence angle lying between 0.degree. and 30.degree.;
and
said second convergence angle lying between 60.degree. and 90.degree..

12 more elements

A headbox device for a papermaking machine and having a predetermined direction of flow for a fiber stock suspension passing through the headbox device, comprising:

means defining a nozzle chamber through which the fiber stock suspension is passed from the headbox to the papermaking machine;
said nozzle chamber comprising two lip members defining a slice opening for the outflow of the fiber stock suspension;
at least one of said two lip members of said nozzle chamber comprising at least two sections with substantially different angles of inclination converging with respect to said predetermined direction of flow of the fiber stock suspension;
at least one section of said at least two sections having a first converging inclination angle of said substantially different converging inclination angles;
said first converging inclination angle lying between 0.degree. and 30.degree.;
said at least one section bounding a quieting zone for substantially equalizing flow velocities of the fiber stock suspension;
at least one further section of said at least two sections having a second converging inclination angle of said substantially different converging inclination angles;
said at least one further section bounding an acceleration zone for abruptly accelerating the fiber stock suspension;
said second converging inclination angle lying between 60.degree. and 90.degree.;
said at least one section having said first converging inclination angle being located on an inlet side of said nozzle chamber;
said at least one further section being located substantially immediately upstream of and in close proximity to said slice opening as viewed in said predetermined direction of flow of said fiber stock suspension;
and
said at least one section having a length which is greater than the length of said at least one further section.

10 more elements

Dependencies are inferred from the claim text.