Pulper device for the recovery of paper production waste, plant comprising said device and associated method for recovery of the waste

Abstract

The pulper device for waste paper material comprises: a container (9) for collecting said waste, having an inlet opening (11) for said waste, at least one pressurized water nozzle (13; 15) which produces a jet of water which intercepts the waste which falls into said container, and a first pump (27) which removes the water and waste from said container.

Description

DESCRIPTION[0001] 1. Technical field[0002] The present invention relates to a device for recovery of paper production waste in paper mills for the continuous production of paper webs, in particular but not exclusively of so-called "tissue" paper. More particularly, the invention relates to a pulper to be combined with a yankee drier in a continuous paper production machine, for the recovery and recycling of processing waste from the drier itself.[0003] The invention also relates to a method for recovery and recycling of the production waste.[0004] 2. State of the Art[0005] In the production of paper, and in particular in the production of tissue paper, typically used as toilet paper, multipurpose drying paper and for other uses, a slurry of cellulose fibers and water is distributed from a head box onto a forming wire or onto a felt for forming a web. By means of successive passes, during which the water content in the slurry is gradually reduced, the web is conveyed to a section of ...

AI Technical Summary

Benefits of technology

[0009] According to a first aspect, an object of the present invention is to provide a device which avoids the abovementioned drawbacks and is particularly suitable for the recovery of waste, trimmings or other paper scrap, especially that which is produced around the yankee drier.

[0012] According to a first practical embodiment of the invention, in order to obtain effective demolition of the fiber structures forming the scrap or waste paper material, a first series of pressurized water nozzles and a second series of pressurized water nozzles are envisaged. Moreover, the nozzles are oriented so that the jets produced by the nozzles of the first series and the jets of the nozzles produced by the second series have trajectories which intersect in a zone where the waste or scrap falls. In this way, the scrap is struck by jets oriented in the incident directions, said jets exerting an efficient cutting, pulling and / or breaking action on the fiber structure. This facilitates the subsequent reintroduction, into the cycle, of the fibers at least partially individualized, i.e. separated from each other.

[0018] In order to facilitate the entry of the scrap, waste or other residual paper material into the device, according to a preferred embodiment of the invention, the container is connected to a suction duct which sucks air from the inside of said container. In this way, multiple advantages are obtained.

[0019] Firstly, entry of the waste which is in the form of pieces of paper is facilitated. Moreover, the vacuum which is produced inside the container results in the formation of an air flow from the outside toward the inside of the container, which sucks into the container also the waste in the form of dusts or fibers or cellulose particles suspended in the atmosphere. These dusts are formed in large quantities owing to the action of the doctor blade which separates the web from the yankee drier. Efficient removal thereof is a guarantee of improved hygienic / sanitary conditions inside the warehouse where the plant is situated, in addition to greater safety against fire hazards. Thirdly, the fibers which are sucked inside the container owing to the vacuum are at least partly intercepted by the pressurized water jets and then automatically introduced into a water flow with the possibility of being recycled together with the fibers of the larger size structures which form the main waste produced by the yankee drier. A combined filtering and fiber-recovery effect is thus obtained.

Problems solved by technology

During the continuous production of the paper web, breakages of the web with consequent waste production may occur.

Moreover, the edges of the web are cut with the formation of trimmings since they have irregularities which would be unacceptable in the finished product.

At present, the waste which is produced underneath the yankee drier or other equivalent drying system is recovered manually and conveyed away for recycling by means of operations which are very labor-intensive.

In addition to the cost which this represents, the presence of production waste around the machines constitutes a serious danger, since the cellulose fibers are highly inflammable.

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