A. Ahlstrom Corporation

Ahlstrom Corporation

Enso-gutzeit Oy

Enzo-gutzeit Oy

Erkki E Savolainen

Kaj Henricson

Olavi E Pikka

Raimo O Kohonen

Harri T Qvintus

Seppo K Kokkonen

Tapani Niiranen

Erkki A Ruuskanen

Risto A Ljokkoi

Juha S Titoff

Pentti Vikio

Jukka Heino

Antti Kuhasalo

Seppo Kokkonen

Pekka Purho

Jari Siitonen

Jorma Vento

Method and apparatus for treating a fiber suspension

An appratus for treating medium consistency pulp in connection with different treatment apparatuses, such as washers. According to the prior art the treatment of pulp, for example, the washing process, starts at a low consistency, approximately 1-3% so that it is necessary always to dilute pulp before washing, whereby the water consumption of the plant increases and the need of power in, for example, pumping and in the treatment generally increases. The present invention makes it possible to treat medium consistency pulp, because the feeding means is able to spread the pulp as an even layer on the perforated surface of the treating apparatus.

Apparatus for treating pulp

A disc filter and method of operating same is provided in which a liquid jet is intermittently used to detach pulp cake from the disc filter. In operation, mechanical or electrical means actuate a nozzle to spray pressurized fluid at a portion of the boundary between the surface of each disc filter segment and its associated pulp cake. The nozzle is actuated to begin spraying as respective segments move into register with the nozzle and are cause to discontinue spraying prior to moving out of register when the loosened pulp cake falls from the segments by gravity. the improved control of pulp cake removal reduces use of washing fluid and results in improved pulp cake consistency.

Method and apparatus for improving the operation of a disc filter

An apparatus for treating, e.g., washing or filtering, fiber suspensions having a consistency of 8-20%, the apparatus including at least on rotatable filtering surface, an arrangement for feeding the suspension to a treatment region of the apparatus, and an arrangement for discharging the suspension from the treatment region, the feeding arrangement including at least one pressure chamber for fluidizing the suspension, at least one inlet duct for introducing the suspension to the chamber, and at least one feed duct for transferring the suspension from the pressure chamber to the treatment region.

A method for improving the operation of a disc filter used for the filtering of fluids containing solid matter such as fibers. Known filtering methods have the drawback that the rate of water exhaustion is limited, because a vacuum tends to be created inside the sectors when the filtered fluid is drained by suction from the central channel of the disc filter. This drawback is an obstacle to increasing the speed of rotation and therefore to increasing the capacity of the disc filter. With the method of the present invention, this problem is solved by providing the disc filter with a means of admitting ambient air into the disc sectors and the central shaft channel and/or with equipment for blowing air into the sectors and the channel to remove the filtered fluid from them.

Disc filter

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). It is essential in the invention that the connecting tubes of the feed and accept ducts (7,8) have been so placed on the different hydrocyclones (1) that the tubes are located substantially in parallel, that the feed and accept ducts have been formed inside a common shell (5) by dividing the space confined by it into two parallel ducts by means of a zigzag partition (6), and that the ends of the connecting tubes (11,12) are located at the folds formed by the bights of the partition, the partition confining the feed duct connecting tubes to be on the feed duct side and the accept duct connecting tubes to be on the accept duct side.

Feed and accept duct system for hydrocyclones

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Haapakallio, Finland

Erkki E Savolainen