Abstract: Cylindrical screen, particularly for paper pulp, of the type comprising at least one filtering element (10) positioned between two flanges (1, 2) by means of a number of bars (3). The filtering element is composed by wires (10) placed side by side and held by rings (11). This filtering element is rigid in the axial direction and is placed upstream from the above mentioned bars (3), in relation to the direction of flow of the pulp. The filtering element is held against the bars (3) through the rings (11) that are in contact with the bars without being attached to them, so as to maintain its shape by withstanding the pressure exerted by the pulp.

Abstract: The method for de-inking paper pulp produced by the reduction to pulp, with water, of old papers of various qualities according to which a stream of air bubbles (C) is sent through the flow (E2, S2, E3, S3) of pulp at least once, is characterized by the fact that a countercurrent of water (E1) is sent into the stream of de-inking air bubbles after said bubbles have passed through the pulp and become laden with ink particles so that the countercurrent releases the particles (fibers, fines, fillers) borne along by these de-inking bubbles and carries them away.

Abstract: Equipment for deinking paper pulp, wherein the batch of pulp to be deinked is made to circulate to move from top to bottom whereas the air bubbles are introduced at least in the lower part and move from bottom to top, characterized in that the pulp descends from top to bottom while being recycled in several consecutive and superposed stages.

Abstract: Method for separating paper fibers and contaminants for mixtures containing water, fibers, contaminants, paper or cardboard pellets, wherein the mixture is subjected firstly to a screening, secondly to a mashing and then thirdly to a further screening with addition of water, subsequent to which the pulp retained by the screen is evacuated.

Abstract: Sieve with slots or holes, made from a U-shaped section, constituted by a stack of identical circles, each circle (1, 1') being made from a tapered U-shaped section of which the two ends are welded or mechanically connected to one another, characterized in that this stack of circles (1, 1') is maintained tightly between two rings (2-3, 2-'3') by a plurality of tie rods (4, 4') and in that the lateral walls of the circles in the stack rest on one another without any further fastening together, so that the walls of the sections can undergo elastic deformation under the effects of the tightening.

Abstract: A method for deinking paper pulp, wherein the batch of pulp to be deinked is made to circulate to move from top to bottom whereas the air bubbles are introduced at least in the lower part and move from bottom to top, characterized in that the pulp descends from top to bottom while being recycled in several consecutive and superposed stages.

Abstract: A cylindrical screen within which rotates a rotor fitted with means causing pressure variations and/or turbulence. The rotor (1) consists of one or several cylindrical surface segments (2) which when geometrically developed are right triangles of which the two perpendicular sides (3, 4) resp. correspond to the cylinder base (3) and to the height (4) and of which the oblique side (5) constitutes the hypothenuse.

Abstract: An air injector for the foaming of paper pulp, comprised of a hollow cylindrical tube inside which is arranged a cylindrical bore (3) leading into a convergent portion and a divergent portion (2a, 2b, 2c), said cylindrical bore being occluded by a stopper fitted with holes (8) providing a cylindrical air inlet chamber (3a).

Abstract: The invention concerns a rotor for the pressurized, hydrodynamic purification of paper pulp from old papers in known purifying equipment comprising a cylindrical screen, characterized in that it comprises a generally cylindrical case extending along a longitudinal axis of rotation 6 and comprising a sequence of n identical elements 8 arrayed side-by-side along the longitudinal axis 6, the screen-side wall evincing a shoulder 14 on either side of which it winds spirally around the longitudinal axis over at least 360.degree., the base and the top of the shoulder subtending a very slight angular gap .OMEGA. relative to said axis in such manner that the shoulder side 14 slopes toward the screen surface, the slope angle .alpha. relative to the radial plane through the shoulder base being between 5 and 80.degree., the elements 8 being mutually shifted in the direction of rotation around the axis 6 by an angle .beta. with a magnitude of at least 360.degree./n, where n is at least 3.

Abstract: An apparatus for separating out the contaminants in a pulp slurry in which the housing of the separator is divided by a perforated screen into an inlet and an outlet section. The inlet section of the separator has a rotating blade mixing means to propel the liquid mixture in the pulp slurry away from the screen and toward the housing wall. The outlet section of the separator has a rotating blade cleaning means which is adjacent the downstream side of the screen for removing contaminants from the upstream side of the screen and moving the removed contaminants into the inlet chamber for further mixing and removal therefrom.

Abstract: Cylindrical sieve for paper pulp strainer of the type of thin sheetmetal is formed by juxtaposition of U-shaped sectional elements (2) made from a metal strip. The element (2) has a first flange (3), a bottom (4), followed by a second flange (5) bent over toward the exterior of the U-shaped element on itself so as to define a space (6) in the fold thus formed, intended to receive and hold the first flange (3') of the adjacent element (2'). The base of the U-shaped element is pricked to form depressions or slots.

Abstract: Process of making and mounting an end rim of a cylindrical sieve (1) for paper pulp strainer and classifier characterized by the fact that the rim is of one piece, molded directly on the end of the cylinder with a hardenable or thermosetting plastic material.

Abstract: The device comprises a closed chamber (1) equipped with an inlet pipe (3) for the aerated liquid, an outlet pipe (4) for the deaerated liquid, and an air evacuation pipe (5); and a rotor having a shaft extending into the chamber. The shaft carries means (7) for centrifugation of the liquid and means (8,9,10) for intensive agitation of the centrifuged liquid.The device works according to the following process: continuously, the liquid is introduced into the closed chamber and it is vigorously centrifuged there in with the aid of mechanical means (7) and simultaneously subjected to intensive agitation with the aid of second mechanical means (8,9,10).The released air gathers freely at the center of the chamber whence it is evacuated, as the deaereated liquid is evacuated through the outlet pipe.

Abstract: Sieve for paper pulp strainer and classifier of the kind formed by the juxtaposition of elements of U-shaped cross section comprising a perforated flat bottom (2) and two sidewalls (3) characterized in that the elements (1) of U-shaped cross section are disposed so as to form a notable cylindrical revolving wall, provided with slots or holes, whether or not associated with grooves and bars (obstacles).

Abstract: Paper pulp beater of the type having a cylindrical vat, open at its upper part, and closed by a bottom equipped with a rotor over which rises a vertical shaft extending along the central axis of revolution of the vat in the interior of the vat, the lateral wall of the vat having a device for force recirculation of the pulp, in that the recirculation device (7) includes at least one surface element (8, 21) extending substantially circularly along the wall (9) of the beater, running from the wall toward the interior of the vat (1) and toward the upper opening (20) of the beater, over a constant distance (12, 22) so as to form a band of constant width, one of the faces (24) of the element being oriented toward the bottom of the vat, so that the pulp (6) encountering this face (24) is diverted into the interior of the vat in a single direction (FIG. 3).

Abstract: Apparatus for treating of old printed papers includes a recycling conduit for the thickening waters of a long fiber fraction upstream of the fractionation apparatus to the pulping and pre-purification apparatus, and a reservoir for the recovery of thickening waters of a short fiber fraction and of thickening/washing waters of the long fiber fraction. This reservoir is fed with clean water for starting the installation and is connected with a second reservoir such that overflow from the first reservoir empties into the second reservoir.

Abstract: A screening device is provided with a screening element having a plurality of perforations going therethrough. Each perforation has an inlet and an outlet.The screen element includes a plurality of step-type obstacle members positioned in the vicinity of the inlets of the perforations to produce turbulence in a flow of a fluid passing through the perforations. Each obstacle member has a shielding member positioned substantially above the inlet so that a gap is defined between the shielding member and the screening element. The shielding element extending over the inlet of the perforation forms an entry baffle above the outlet.At least one blade having a hydrodynamic profile rotates at high speed above the shielding element.

Abstract: The invention relates to a sieve for a paper pulp scrubber or similar equipment, and to a method for fabricating such a sieve. The sieve is produced by mechanical interfit of bars with support members, the bars carrying notches, the lips of which engage at least one V-shaped lateral groove formed in each support member, while the support members present, on their face receiving the bars, a first set of notches for positioning the bars. The cross-section of the support members at the level of the first notches has the same configuration and dimensions as the cross-section of the second notches and the cross-section of bars at the level of notches has the same configuration as the cross-section of notches formed in the support members. Assembling is made by bending a bar by an angle of about 20-25.degree. for widening a second notch and inserting a support member therein. The bar is then straightened back, so that the support member will be firmly clamped in the notch.

Abstract: The invention relates to a multiple liquid injector composed of several identical elementary injection tubes 2, disposed in a rim around a central tube. Each tube 2 has an inlet conduit 3, itself comprising a converging truncated cone 6 and a cylinder 7, followed by an aeration zone 4 comprising an aeration chamber 8 fed tangentially by a conduit 9 perpendicular to the tubes 2, a jet centering funnel 10, followed by mixing cylinder 11, and lastly a diverging outlet conduit 12.

Abstract: A valve arrangement has an outflow seat section defined by at least a tubular side wall. The outflow seat section has a free end with an engaging part extending along the entire periphery of the side wall. The engaging part is adapted for close engagement with an engaging surface of a movable obturating plate. The engaging surface is substantially parallel to a plane of the engaging part and remains substantially parallel to this plane during movement of the obturating plate toward and from the free end of the outflow seat section. During operation of the valve arrangement the engaging surface of the obturating plate simultaneously engages the entire plane of the engaging part of the outflow seat section causing closing of the valve arrangement.