Abstract: 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.

Abstract: 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.

Abstract: Structure for facilitating separation of a web and wire in a paper machine. Steam is supplied to the wire at the separating location where the web and wire separate from each other at a side of the wire opposite from the side where the web forms so as to facilitate separation of the web and wire from each other. Steam is supplied from the interior of a container which has a foraminous wall directly engaging the wire so that through the pores of the foraminous wall the steam will discharge to be conducted to the wire. The structure is particularly suitable in connection with twin-wire formers as well as in connection with the manufacture of tissue paper.

Abstract: A web-forming method and apparatus to be used in the manufacture of paper. A web is formed at one side of a travelling wire while at the opposite side thereof, from a location in close proximity thereto, jets of steam are directed toward the wire to produce an implosion at the opposite side of the wire, as well as directly in the wire and in the web. The jets of steam issue from openings in the wall of an enclosure which is situated in close proximity to the said opposite side of the wire, this enclosure having in its interior steam which issues through the openings to form the jets. A plurality of these enclosures may form part of a forming board, and also one or more of the enclosures may be situated along the wire at a part thereof which has travelled beyond the forming board.

Abstract: A structure for keeping clean the interior of the headbox of a paper machine as well as contributing to the homogeneity of the stock flowing through the headbox. At a location in the headbox where there is a tendency for accumulation or build-up of matter such as fibers, fillers, slime, or the like, steam is introduced such as by supplying steam to the interior of a hollow body having a wall provided with passages through which the steam can escape to the exterior of the hollow body into the stock in the headbox.