FI73748B - FOERFARANDE FOER BEREDNING AV AVFALLSPAPPER. - Google Patents

Description

73748

Method for cleaning waste paper

The invention relates to a method for cleaning waste paper according to the preamble of claim 1.

To date, waste paper has either been decomposed in a pulp dispenser at low consistency and then passed to other processing steps such as cleaning, sorting and thickening, or the waste paper has been decomposed in a pulp decomposer at high consistency, e.g. more than 20% and then diluted in either and to a sortable consistency diluted from a pulp mill to other processing stages. In any case, a thickening device is required in this way, so that the whole method becomes more expensive and thus also more extensive.

It is now an object of the invention to provide a simpler method which is particularly suitable for relatively pure, i. for cleaning either pre-sorted waste paper or papermaking waste papers, e.g. wet strength parts.

This object is solved according to the invention by means of the characteristic features of claim 1.

In this way, according to the invention, a fast and fast processing method is achieved, which is considerably simpler than the known ones.

It is very advantageous to have to clean lightly soiled waste paper, in which case interfering contaminants refer in particular to heavy parts such as screws, stones, wires, etc. large parts such as films, pieces of wood, textiles, etc., because in this case very fast cleaning of the waste paper is possible. paper board; printing inks contained in waste paper __________________________ ΤΓ. . . ____________ 73748 will not be removed in this case, but will be fine-tuned in the next process.

A very advantageous embodiment of the method is possible by using a disc fiberizer, because its working point and effect can be adapted to the present pulp consistency by adjusting the gap between the discs and thus are relatively free in the choice of pulp consistency in the pulp diffuser.

In the following, the invention will be explained by means of an exemplary embodiment shown schematically in the drawing.

It can be seen from the drawing that the path of the pulp passes from the pulp diffuser through the closing member 10 and the discharge coil 2 and the conveyor belt 3 to the disc fibrous web 4, where the suspension is dispersed. Above the conveyor belt 3 there is a metal detector device 5 to ensure that metal parts in the suspension, such as e.g. screws and connectors or the like, cannot enter the sorting devices or even the paper machine behind the pulp. In the disc pulverizer, the coagulates are removed from the pulp to the required fineness, i. decomposed into individual fibers and dispersing, for example, the inks contained therein. In this pulp, the pulp consistency is about 20%, especially more than 20%, and it remains unchanged from the pulp diffuser to the disc pulverizer. The most favorable pulp consistency, which can also be less than 20%, is selected either individually according to the mode of operation of the pulp diffuser or taking into account the capabilities of the disc fiberizer, i. its possible slit widths. In general, however, the operating point of the disc fiberizer can be adjusted by fully adjusting its working gap to the most favorable consistency for the pulp diffuser.

Of course, a second dispersing device can also be chosen instead of a disc fiber, in particular e.g. a single-axis fiber with no adjustable working gap, so that there is no free choice of pulp consistency in the pulp diffuser, but must adapt to the optimum operating point of the single-axis fiber.

73748

After the disc fiberizer, the pulp is delivered via a conveyor belt with a reversible conveying direction in continuous operation to an intermediate bath where dilution takes place. It is necessary for subsequent fine sorting and pulp cleaning to ensure the conditions for sortability. The transport from the intermediate bath 8 takes place via the pump 9. A wide variety of sorting devices can then be connected, such as screen sorting devices, in particular vertical screens and also flotation devices. Of course, flotation devices are not required when using unprinted waste papers and / or only parts (waste) from papermaking as waste paper. When the device is started, the conveyor belt can travel in the opposite direction and transport the pulp after the disc pulverizer via the return coil 11 again to the pulp diffuser, because a certain transition time is required before starting the pulp before the pulp has the required properties according to the disk pulverizer.

It is further shown in the figure that the pulp is fed to the disc fiberizer 4 via a feed coil 12. In the case where a uniaxial fiberizer is used, a very fine pulp consistency is required in the pulverizer, e.g. perhaps about 30%, in exceptional cases at most 35%, which, however, can be completely controlled by this. When a disc fiberizer is used, the consistencies are lower and can be varied over a wide range, as already mentioned above.

Claims (6)

A method for cleaning relatively clean pre-sorted waste paper, in particular papermaking waste papers, characterized by the following characteristics: a) decomposition in a pulp diffuser (1) with a pulp consistency of more than 15%, b) removal from the pulp decomposer (1) sorting the pulp-like pulp by passing it past the metal picking device (5), d) feeding the dispersing 1 to a device (4) having a working range within the pulp density set in the pulverizer (1), e} pulp dispersing in the dispersing device (4), f) (g) other cleaning of pulp by fine sorting and cleaning to feed it to a paper or board machine. Method according to Claim 1, characterized in that the pulp consistency is adjusted in the pulp diffuser (1) depending on the (most optimal) operating point of the dispersing device (4). Method according to Claim 1 or 2, characterized in that a dispersing pad (disc fiber) with an adjustable working gap is used, the working gap being adjusted to the optimum operating position of the dispersing pad relative to the pulp structure. Method according to one of Claims 1 to 3, characterized in that the removal from the pulp diffuser (1) is carried out by means of a drain screw, a gutter chain conveyor or a belt conveyor. Device for carrying out the process according to one of Claims 1, 2 or 4, characterized in that the dispersing device is a single-axis fiberizer. 5,73748 Device for carrying out the method according to one of Claims 1, 3 or 4, characterized in that the dispersing device (4) is a double-disc fiberizer with an adjustable gap between the discs.