Abstract: A method and apparatus treat fiber based material so as to reduce the loss of mineral fractions in the treatment of broke in paper production. Broke is a reusable raw material from a paper machine that contains mineral fractions which are desirably returned to the process as a raw material. The material containing minerals is dispersed into broke pulp, which is fractionated, and the accepts from the fractionation are returned to the paper manufacturing process providing for efficient and economical recovery of the minerals in broke. The mineral fraction provided in the rejects from the fractionation is treated separately before it is reused as filler or coating material in the production of paper or board.

Abstract: A method and apparatus for treatment of recycled fiber material and/or of the reject fraction discharged from paper mill screening systems of the short circulation of a paper machine, recover fillers as completely as possible and return the fillers back to the process as efficiently and economically as possible. The loss of fiber/mineral discharge as mill rejects from vortex cleaning and filler manufacture is decreased by treating a concentrated mineral fraction of the rejects to disperse the filler-mineral fraction and return the filler back to the paper making process.

Abstract: Rejects from a conventional first set of cleaners from a system feeding recycled cellulosic fiber slurry to a paper machine or rejects from the paper machine approach system cleaners are fractionated to produce a first, fine fraction, stream and a second, coarse fraction, stream containing most of the fiber and larger solids. The second stream is acted upon by a disperser, deflaker, or like mechanical agitating device, to disrupt the fiber flocs and reduce the size of solids to produce a third stream containing few or no fiber flocs and no large particles. The third stream may be diluted and cleaned in a second set of cleaners, and then is returned to the first set of cleaners (e.g. to the inlet of the first stage or between the first and second stages). Ink, and other fine undesirable particles may be removed from the first stream via flotation or cleaning, and the cleaned stream may also be returned to the first set of cleaners if desired.

Abstract: Recycled fiber pulp from a vortex cleaning plant (e.g. connected to the short circulation of a paper machine) effects the recovery and return of fillers in the recycled fiber pulp discharged from the vortex cleaning plant, in an efficient and economical manner. The loss of filler in the recycled fiber pulp discharged from the vortex cleaning plant is decreased by treating a concentrated fraction of the rejects from the vortex cleaning plant with a mixer/disperser for dispersing the filler in the recycled fiber pulp, and returning as much usable filler as possible back to the process.

Abstract: White water from a paper machine is treated in an improved fiber recovery process, i.e., the "save-all" process. Prior to the mixing of sweetener stock into the white water the sweetener stock is fractionated (undiluted) into fine and coarse fiber fractions, of which only the coarse fraction is fed as sweetener stock into the white water. The inlet line for the sweetener stock is provided with a fractionation apparatus for removing the fine fraction from the sweetener stock. Treatment apparatus may also be utilized to separate the white water into fine and coarse fractions before passing the fine fraction to a mixer for mixing with the sweetener stock coarse fraction.

Abstract: White water from a paper machine is treated in an improved fiber recovery process, i.e., the "save-all" process. Prior to the mixing of sweetener stock into the white water the sweetener stock is fractionated (undiluted) into fine and coarse fiber fractions, of which only the coarse fraction is fed as sweetener stock into the white water. The inlet line for the sweetener stock is provided with a fractionation apparatus for removing the fine fraction from the sweetener stock. Treatment apparatus may also be utilized to separate the white water into fine and coarse fractions before passing the fine fraction to a mixer for mixing with the sweetener stock coarse fraction.

Abstract: A method and an apparatus for separating heavy impurities from a fiber suspension include a centrifugal pump capable of separating heavy impurities towards the periphery of the interior chamber of the pump. The fiber suspension is caused to rotate in the interior chamber so as to urge the suspension downstream as well as separate the impurities towards the periphery of the chamber where they can be collected.

Abstract: A deaeration vessel has a partition wall dividing the hollow vessel body into first and second portions, and defining a weir with a top surface establishing the level of pulp suspension in the vessel body. Turbulence in the deaerated pulp is minimized by providing the outlet for deaerated pulp immediately adjacent the partition wall, in the bottom of the vessel body first portion (on the same side of the weir as the inlet conduits for the suspension being deaerated). The weir is preferably configured so that the top surface, defining the liquid level within the vessel, overlies the outlet. A partition wall may extend substantially linearly at an angle of about 60.degree. to the bottom of the vessel, or it may have a vertical bottom with a top extending at an angle to the bottom, or it may be continuously curved from the vessel bottom to the top surface, about a horizontal and/or vertical axis.

Abstract: Method and apparatus for treating a gas containing aqueous fiber suspension in a fiber line process of a pulp mill including at least one of pulp screening, washing and bleaching includes (a) transferring the gas containing fiber suspension at a consistency to a treatment station; (b) treating said fiber suspension at the same level by removing a portion of the water from the fiber suspension so as to generate aqueous filtrate and treated fiber suspension having a relatively higher consistency; (c) simultaneously pumping and degassing the filtrate at the same level; and (d) pumping the treated fiber suspension having the relatively higher consistency away from the treatment station at the same level by imparting to the treated fiber suspension sufficient shear force so as to render the fiber suspension pumpable.

Abstract: A hydrocyclone is provided with a wear monitoring element of the type of a tube (24) or the like embedded in the wall section of the shell of the hydrocyclone. When the furrows worn by abrasive fraction of the cyclone are deep enough to reach the monitoring element, the wear causes a visually observed leak or some other signal alerting the operating personnel to the need of replacing the partly worn hydrocyclone.

Abstract: A method of separating an aqueous solids containing suspension includes (a) subjecting a first solids containing suspension to centrifugal forces so as to separate the suspension into a first gas containing flow, a second gas-free flow and a third flow; (b) feeding the third flow into a flotation cell having a bottom; (c) introducing air at the bottom of the flotation cell into the third flow for separating from the third flow a fourth partial flow; (d) withdrawing the air containing third flow after the separation of the fourth partial flow from the flotation cell; and (e) subjecting the third flow to the centrifugal forces of step (a).

Abstract: A method and apparatus for the removal of light material from a fiber suspension particularly suitable for removing light compressible plastic material such as expanded polystyrene and similar material from the short circulation of a paper machine. The plastic particles containing fiber suspension is divided in a degassing tank into reject and accept flows by the assistance of vacuum. The light reject containing flow is separated from the main flow by an overflow device and recirculated to the wire pit or corresponding device. A separation device such as a vibrating screen, vibrating drum, curved screen or inverted cyclone is provided within the light reject flow return duct for removing the detrimental plastic or other light material from the short circulation and for preventing the accumulation thereof in the wire pit.

Abstract: A method and apparatus allow the efficient grading of a fiber suspension (e.g. paper pulp) having a consistency of 0.5% or more. A cyclone separator has its rejects outlet connected to a rejects chamber with a solid confining surface. A rotor is mounted for rotation in the rejects chamber adjacent its discharge opening, and accelerates the rotational speed of suspension flowing into the rejects chamber to continue the grading action of the cyclone. Accepts that are discharged from the rejects chamber are recirculated to the inlet to the cyclone separator, while the rejects are passed out for disposal or other action. Vertically extending ribs may be provided along the solid interior walls of the rejects chamber, which act with the rotor to efficiently break up fiber flocks in the suspension.

Abstract: Apparatus for clearing the blocked reject end of a vortex purifier without interrupting the operation of the vortex purifier, the apparatus includes an opening device for detaching the bottom plug of the reject end of the vortex purifier and an exit aperture for conducting off the reject of the vortex purifier. For enhancing the operation of the device of this type known in prior art, a valve is provided connected to the reject end of the vortex purifier for the duration of opening the plug, and that the device extending through the valve can be removed and replaced with a cleaning member, with the aid of which the blockage remaining in the reject end in spite of the removal of the bottom plug can be cleared.

Abstract: A twin hydrocyclone used for instance in cellulose and paper mills for purifying pulp suspension, the twin hydrocyclone consisting of two hydrocyclones mounted with their larger ends against each other and having one common infeed connector and one common purified fraction discharge connector. The hydrocyclones of prior art have the drawback of complex design and of division of the feed flow causing disturbances in the feed flow in view of the hydrocyclone's operation. The twin hydrocyclone, meant to solve these problems, is characterized in that the feed flow from the common infeed connector of the hydrocyclones is directed to each hydrocyclone as a separate feed flow by means of a helical member the helices of which constitute, in each hydrocyclone, feeding ducts confined by the walls of the hydrocyclones.

Abstract: The present invention concerns a feed and accept duct system (4) for hydrocyclones (1), comprising common feed and accept ducts (7,8) which have by connecting tubes been connected to the parallel hydrocyclones. This type of construction is used, for instance, in purifying fiber suspensions, in which process the suspension is fed into the hydrocyclones (1) and the purified suspension is removed therefrom as a so-called accept fraction into the accept duct (8).

Abstract: A device for cleaning obstructions from the reject end of a centrifugal separator without interrupting normal opertion. Modern small-sized separators, in particular, are liable to become blocked, and the usual method of removing the blockage is to use a water jet or pressurized air which is led to the obstructed reject end by various methods. The disadvantage associated with these methods is that the impurities removed by the jet partially contaminate the regular flow. This invention will help to avoid this because cleaning is effected by means of a device having a chamber into which the flow containing the rejected material is directed when the plug of the separator is opened. The chamber is fitted with a discharge orifice. In this way, the reversed flow removes the obstruction in the reject orifice, thus preventing it from contaminating the accept mass.

Abstract: Hydrocyclone for dividing a substance mix into an acceptable fraction and a reject fraction containing dirt substances, the hydrocyclone including a separating chamber, which in part consists of a cylinder part, provided with at least one tangential feed connector for the substance mix and with a coaxial exit tube for the acceptable fraction, and which in part consists of a sorter cone on the extension of the cylinder part, having at its apex an exit aperture for the reject fraction.

Abstract: Hydrocyclone for dividing a fibre suspension into a lighter acceptable fraction containing fibres and a heavier reject fraction containing dirt substances. The hydrocyclone comprising a separation chamber consisting in part of a cylinder part provided with at least one passage for the tangential input of the fibre suspension to be divided into different fractions and having within itself a coaxially disposed tube for removal of the lighter fraction, and in part of a sorter cone on the extension of said cylinder part and on the apex of which has been adjoined a conical nozzle which has been made more abruptly tapering than the cone part and which at its apex has a removal aperture for the heavier fraction.

Abstract: Recycled fiber pulp from a vortex cleaning plant (e.g. connected to the short circulation of a paper machine) effects the recovery and return of fillers in the recycled fiber pulp discharged from the vortex cleaning plant, in an efficient and economical manner. The loss of filler in the recycled fiber pulp discharged from the vortex cleaning plant is decreased by treating a concentrated fraction of the rejects from the vortex cleaning plant with a mixer/disperser for dispersing the filler in the recycled fiber pulp, and returning as much usable filler as possible back to the process.