A device for filtering fiber suspensions

Abstract

A device for filtering of fiber suspensions comprises a vat with an inlet for the suspension. In the vat has been arranged a rotatable axis with peripheral channels and at least one disc-like filter element, set at an angle against the rotatable axis. The filter element has a filtering surface and inner flow channels for transporting filtrate, which has passed through the filtering surface, to oneor more channels in the inner rotating axis. The liquid flow in the channels is combined in one end of the rotating axis into at least one barometric downpipe in order to generate the vacuum necessary for filtration. There are means for detaching material deposited on the filtering surface, filtered out of the suspension. Additionally, there are means for guiding out-filtered material down into areceiving chute and for cleaning the filtering surface by means of a number of spray nozzles, and means for flushing the out-filtered material down into at least one receiving chute. Detaching means,washing means and receiving chute are arranged beside the filter element. At the outlet end of the receiving chute and by the bottom part of the vat, there is a transport means with an actuator, arranged to combine and transport away the out-filtered material.

Description

technical field [0001] The object of the present invention is to increase the operational reliability and to improve the filtration results of disc filters for filtering fibrous suspensions, in particular to devices for filtering fibrous suspensions which are characterized by relatively easy dewatering. The invention can also be used for suspensions which are difficult to dewater. Background technique [0002] The term "fiber suspension" refers to liquids and suspensions which contain fibers and other constituents present which are to be filtered out. These fibers are usually regenerated cellulose fibers, but newly produced cellulose fibers can also be problematic. [0003] There are mainly three related types of disc filters in this paper. In the first type of disc filter, a filter for removing detached material is provided between two adjacent discs for filtration. A device shaped like a chute so that its lower part conveys material to a receiving device, the first type ...

AI Technical Summary

Problems solved by technology

In order to avoid scraping and thus thickening in the filter cylinder, the distance between the chute and the rotating disk must be made larger, which also leads to this solution making the filter plant less economical

[0007] The second main type of disc filter has the disadvantage that its construction is relatively expensive in the case where the internal longitudinal screw conveyor is placed inside the rotor part of the filter

There is also a big disadvantage that a failure of the conveyor will render the entire filter unusable

[0008] The third main type of disc filter has the disadvantage that the filtrate is diluted by water jets from a vibrating washing device of the filter surface, which leads to dilution of the filtrate without any control and cannot be designed in an optimal way Devices for removing leachate to avoid the leached pulp sticking to the edges of these devices

Vibrating wash nozzles do not yet provide a completely good washing of the entire filter surface depending on the filter sector speed relative to the vibrating nozzle speed and when the filtered pulp can fall between the wash nozzles and the filter surface of the disc

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