Valmet Oy

Antti Lehtinen

Bjarne Ekberg

Vaino Sailas

Markku Lampinen

Seppo Lepisto

An apparatus, method and band for forming and/or dewatering a fibrous web, in which the web or a pulp suspension layer forming the same is conveyed and supported through a significant portion of its run in a paper machine by a specific processing band, while liquid such as water is simultaneously removed therefrom by hydraulically contacting the same with liquid present under vacuum or underpressure within the processing band, through a finely porous, liquid-suction surface on the band that is saturated with liquid.

Method and apparatus for dewatering a fibrous web

An ultrasonic echo sounding device permits observation of the web formation and/or the pulp suspension flow on the wire part and in the head box of a paper machine. The device includes a series of ultrasonic detectors connected to the wall of the flow channel in the head box and/or to the forming wire. The detectors direct an ultrasonic field at the pulp suspension layer, and the echo signals received from the pulp suspension layer are detected. The detectors operate as acoustic lenses so that the focal points thereof are located in the transverse direction of the pulp suspension flow and in the direction of thickness of the pulp suspension layer in a manner whereby information concerning fibre bundles, air bubbles, variations in consistency, corresponding parameters and their variations in the transverse direction of the pulp suspension flow and in the direction of thickness of the pulp suspension layer are indicated by the device.

Ultrasonic echo sounding device for observing web formation and pulp

Ultrasonic frequency sensor/radiators (hereinafter, radiators) are arranged in the vicinity of a material to be treated, on opposite sides of such material, opposite each other. In one embodiment, longitudinal acoustic vibrations are fed to the radiators at the same frequency and the phase difference of the vibrations fed to the different radiators is varied. In another embodiment, the vibrations are fed to the radiators at different frequencies f.sub.1 and f.sub.2 and the frequency difference .DELTA.f of the frequencies, where .DELTA.f=f.sub.1 -f.sub.2, is varied. In each embodiment the most intensive area of the field of vibration combinations in the material to be treated is focused by the radiators in a manner whereby it has an effect upon a desired area of the material.

Method used in paper making for treatment of a weave

Properties of mechanical paper pulp which is produced by grinding or otherwise frictionally acting on natural fibrous raw material containing plasticizable constituents which become heated to a temperature sufficiently high to soften the plasticizable constituents thereof are improved by the addition of paper filler material which is chemically inert to the pulp at a time which results in the filler being in contact therewith while the plasticizable constituents are plasticized and thus softened and sticky. This causes the filler, without chemical reaction, to adhere to the plasticized constituents and thus to the fibers of the pulp to result in improved properties of a totally mechanical pulp. The properties which are improved include the optical and printing properties of the paper made from the pulp.

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Jyvaskyla, Finland

Antti Lehtinen