CA2436379A1 - Pulper device for the recovery of paper production waste, plant comprising said device and associated method for recovery of the waste - Google Patents
Pulper device for the recovery of paper production waste, plant comprising said device and associated method for recovery of the waste Download PDFInfo
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- CA2436379A1 CA2436379A1 CA002436379A CA2436379A CA2436379A1 CA 2436379 A1 CA2436379 A1 CA 2436379A1 CA 002436379 A CA002436379 A CA 002436379A CA 2436379 A CA2436379 A CA 2436379A CA 2436379 A1 CA2436379 A1 CA 2436379A1
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- container
- waste
- water
- nozzles
- pump
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
- D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
- D21B1/30—Defibrating by other means
- D21B1/34—Kneading or mixing; Pulpers
- D21B1/345—Pulpers
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F7/00—Other details of machines for making continuous webs of paper
- D21F7/04—Paper-break control devices
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Mechanical Engineering (AREA)
- Paper (AREA)
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
Pulper device for the recovery of paper production waste, plant comprising said device and associated method for recovery of the waste Descr~tion Technical field The present invention relates to a device for recovery of paper production waste in paper miffs 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.
The invention also relates to a method for recovery and recycling of the production waste.
State of the art 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 2 o gradually reduced, the web is conveyed to a section of the production line where it is more or less dried. Various systems may be used for drying.
One of the most widespread systems consists of a so-called Yankee drier, i.e. a large-diameter cylinder which is heated internally and around which the wet web is conveyed. When in contact with the cylinder, the web dries and is separated from the cylinder by a doctor blade which also performs creping of the paper.
Examples of plants for the production of paper of this type are described in US-A-4,448,638, US-A-5,514,523, US-A-6,3t 9,496 and in other patents cited therein.
The invention also relates to a method for recovery and recycling of the production waste.
State of the art 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 2 o gradually reduced, the web is conveyed to a section of the production line where it is more or less dried. Various systems may be used for drying.
One of the most widespread systems consists of a so-called Yankee drier, i.e. a large-diameter cylinder which is heated internally and around which the wet web is conveyed. When in contact with the cylinder, the web dries and is separated from the cylinder by a doctor blade which also performs creping of the paper.
Examples of plants for the production of paper of this type are described in US-A-4,448,638, US-A-5,514,523, US-A-6,3t 9,496 and in other patents cited therein.
3 0 During the continuous production of the paper web, breakages of the web with consequent waste production rnay occur. PVloreover, the edges of the web are cut with the formation of trimmings since they have irregularities which would be unacceptable in the finished product. This waste and these trimmings must be recovered and recycled.
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 whicr~ 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.
~bLects and summar~r of the invention 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.
These and further objects and advantages, which will become clear to those skilled in the art from reading of the tent which follows, are obtained essentially with a pulper device for waste paper material, characterized in that it comprises: a container for collecting said waste, having an inlet opening for said waste; at least one pressurized water nozzle which produces a jet of water which intercepts the waste which 2 o falls into said container; and a first pump which removes the water and the waste from said container.
A device thus designed may be arranged below the yankee drier or other equivalent assembly in the paper production line, for collecting the waste, scrap and paper trimmings and recycling them automatically, without the need for storing them and transporting them manually away from the working zone. The jet produced by the water nozzle under pressure destroys at least partially the structure of the waste paper material, separating the fibers from each other as the first stage in the recovery process. The cellulose fibers may then be reintroduced into the 3 o production cycle, for example directly or indirectly into the head box which produces the layer of slurry for formation of the paper web.
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 andlor breaking action on the fiber structure. This facilitates the subsequent reintroduction, into the cycle, of 1 o the fibers at least partially individualized, i.e. separated fronn each other.
The nozzles may have trajectories with inclinations which are different from each other. Moreover, advantageously, it is possible to envisage that two inclined surfaces for guiding the jets produced by the nozzles may be associated with the first series and the second series of nozzles. The surfaces, which are for example flat surfaces, rnay be varyingly inclined, but are preferably inclined approximately with the same orientation of the axis of the jets produced by the nozzles. Said surfaces terminate in edges which delimit a passage far conveying the water and the refuse paper material toward the bottom of the container.
According to an advantageous embodiment of the invention, the container has an elongated longitudinal extension such that the inlet opening has an extension approximately equivalent to the axial extension of the Yankee drier, for collecting the refuse, waste or other scrap along the whole of the front of the paper web being formed. In this case, parallel 2 5 to the elongated upper opening of the container, the first and second series of nozzles extend.
In order to obtain improved separation of the fibers of the scrap paper material, according to an advantageous embodiment of the present invention it is envisaged that the pump is a so-called chopper pump.
"Chopper pump" is generally understood as meaning a pump equipped with parts which are able to cut, break, tear or fragment parts or solid bodies contained in the liquid flow sucked by the pump. These pumps are " known per se. They usually consist of centrifugal pumps, the rotor of which is integral with cutting members. Examples of chopper pumps are described in US-A-4,402,648, US-A-4,640,666, US-A-4,519,904, US-A-4,778,336.
In order to permit better use of the water in the plant and in order to facilitate circulation of the mixture of water and fibers obtained by the destruction of the scrap or waste paper material, according to an advantageous embodiment of the invention a recirculation duct is envisaged between the chopper pump, or other equivalent pumping means, and the container. By means of the recircuiation duct, a part of the flow sucked in by the pump is recirculated into said container in a direction such that as to favor suction of the refuse by the pump itself. For this purpose, the outlet of the recirculation duct is situated in a position approximately opposite the inlet mouth of the pump suction duct.
Basically, if the container has an elongated extension, the outlet of said recirculation duct and the intake opening of said pump are arranged approximately at the ends of the elongated longitudinal extension of said container.
Still with the aim of favoring the outflow of refuse paper material 2 o from the container and the suction thereof by the chopper pump, according to an advantageous embodiment of the invention, the bottom of the container is inclined from the top downward and from the outlet of the recirculation duct toward the intake opening of the pump.
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.
Firstly, entry of the waste which is in the form of pieces of paper is 3o 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 to size structures which form the main waste produced by the Yankee drier.
A combined filtering and fiber-recovery effect is thus obtained.
fn order to obtain an optimized circulation of air inside the container, which does not interfere with correct operation of the pressurized water nozzles, according to an advantageous embodiment of the invention, the suction duct has suction openings arranged underneath at least one of said two inclined surfaces.
The air flow sucked from inside the container may convey water droplets in suspension form due to the atomization produced by the pressurized water nozzles, IVloreover, despite elimination performed by 2o the water jets, dusts or fibers may also be entrained in the air stream. In order to eliminate these solid or liquid suspensions, according to an advantageous embodiment of the invention, it is envisaged that the suction duct may be connected to a separator in order to separate the air from 'the solid andJor liquid particles entrained in the air flow. For this purpose, a cyclone separator or an equivalent may be used for example.
The water flow, containing the fiber or residual matter resulting from the collection of scrap or waste paper material, removed from the collection container, has a very low quantity of solid. It is in principle possible to introduce this flow of water and fibers directly into the paper 3 0 production cycle, for example into the head box. However, this could lead to an excessive water content in the cellulose slurry, i.e. to a cellulose content which is too low.
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 whicr~ 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.
~bLects and summar~r of the invention 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.
These and further objects and advantages, which will become clear to those skilled in the art from reading of the tent which follows, are obtained essentially with a pulper device for waste paper material, characterized in that it comprises: a container for collecting said waste, having an inlet opening for said waste; at least one pressurized water nozzle which produces a jet of water which intercepts the waste which 2 o falls into said container; and a first pump which removes the water and the waste from said container.
A device thus designed may be arranged below the yankee drier or other equivalent assembly in the paper production line, for collecting the waste, scrap and paper trimmings and recycling them automatically, without the need for storing them and transporting them manually away from the working zone. The jet produced by the water nozzle under pressure destroys at least partially the structure of the waste paper material, separating the fibers from each other as the first stage in the recovery process. The cellulose fibers may then be reintroduced into the 3 o production cycle, for example directly or indirectly into the head box which produces the layer of slurry for formation of the paper web.
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 andlor breaking action on the fiber structure. This facilitates the subsequent reintroduction, into the cycle, of 1 o the fibers at least partially individualized, i.e. separated fronn each other.
The nozzles may have trajectories with inclinations which are different from each other. Moreover, advantageously, it is possible to envisage that two inclined surfaces for guiding the jets produced by the nozzles may be associated with the first series and the second series of nozzles. The surfaces, which are for example flat surfaces, rnay be varyingly inclined, but are preferably inclined approximately with the same orientation of the axis of the jets produced by the nozzles. Said surfaces terminate in edges which delimit a passage far conveying the water and the refuse paper material toward the bottom of the container.
According to an advantageous embodiment of the invention, the container has an elongated longitudinal extension such that the inlet opening has an extension approximately equivalent to the axial extension of the Yankee drier, for collecting the refuse, waste or other scrap along the whole of the front of the paper web being formed. In this case, parallel 2 5 to the elongated upper opening of the container, the first and second series of nozzles extend.
In order to obtain improved separation of the fibers of the scrap paper material, according to an advantageous embodiment of the present invention it is envisaged that the pump is a so-called chopper pump.
"Chopper pump" is generally understood as meaning a pump equipped with parts which are able to cut, break, tear or fragment parts or solid bodies contained in the liquid flow sucked by the pump. These pumps are " known per se. They usually consist of centrifugal pumps, the rotor of which is integral with cutting members. Examples of chopper pumps are described in US-A-4,402,648, US-A-4,640,666, US-A-4,519,904, US-A-4,778,336.
In order to permit better use of the water in the plant and in order to facilitate circulation of the mixture of water and fibers obtained by the destruction of the scrap or waste paper material, according to an advantageous embodiment of the invention a recirculation duct is envisaged between the chopper pump, or other equivalent pumping means, and the container. By means of the recircuiation duct, a part of the flow sucked in by the pump is recirculated into said container in a direction such that as to favor suction of the refuse by the pump itself. For this purpose, the outlet of the recirculation duct is situated in a position approximately opposite the inlet mouth of the pump suction duct.
Basically, if the container has an elongated extension, the outlet of said recirculation duct and the intake opening of said pump are arranged approximately at the ends of the elongated longitudinal extension of said container.
Still with the aim of favoring the outflow of refuse paper material 2 o from the container and the suction thereof by the chopper pump, according to an advantageous embodiment of the invention, the bottom of the container is inclined from the top downward and from the outlet of the recirculation duct toward the intake opening of the pump.
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.
Firstly, entry of the waste which is in the form of pieces of paper is 3o 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 to size structures which form the main waste produced by the Yankee drier.
A combined filtering and fiber-recovery effect is thus obtained.
fn order to obtain an optimized circulation of air inside the container, which does not interfere with correct operation of the pressurized water nozzles, according to an advantageous embodiment of the invention, the suction duct has suction openings arranged underneath at least one of said two inclined surfaces.
The air flow sucked from inside the container may convey water droplets in suspension form due to the atomization produced by the pressurized water nozzles, IVloreover, despite elimination performed by 2o the water jets, dusts or fibers may also be entrained in the air stream. In order to eliminate these solid or liquid suspensions, according to an advantageous embodiment of the invention, it is envisaged that the suction duct may be connected to a separator in order to separate the air from 'the solid andJor liquid particles entrained in the air flow. For this purpose, a cyclone separator or an equivalent may be used for example.
The water flow, containing the fiber or residual matter resulting from the collection of scrap or waste paper material, removed from the collection container, has a very low quantity of solid. It is in principle possible to introduce this flow of water and fibers directly into the paper 3 0 production cycle, for example into the head box. However, this could lead to an excessive water content in the cellulose slurry, i.e. to a cellulose content which is too low.
In order to overcome this possible drawback, according to an advantageous embodiment of the invention, a thickening station is provided to which, at least partly, the mixture of water and waste paper material sucked by means of the pump from the container is conveyed. fn the thickening station the solid content of the mixture is increased, eliminating therefrom a part of the water content. The water eliminated is used, however, in the production cycle, for example for supplying the water nozzles.
Thickening stations are known per se and used in paper production 1 o plants. Examples of thickening stations are described in US-A-5,021,151, US-A-5,186,791, US-A-4,501,040, US-A-4,686,005 and US-A-4,722,793.
Further advantageous features and embodiments of the device according to the invention are indicated in the accompanying dependent claims.
According to a further aspect, an object of the present invention is to provide a method for recycling paper scrap, waste or trimmings, in particular formed around the Yankee drier.
This and further objects and advantages, which will be clear to those skilled in the art from reading of the text which follows, are 2 o essentially obtained by means of a method for recovering and recycling waste paper material supplied from a paper production line, characterized in that said waste is subjected to a pulping action by means of at least one or more pressurized water nozzles so as to produce a mi~cture of water and waste paper material and in that said mixture is recycled.
Advantageously, according to a possible embodiment of the method according to the present invention, the waste is reduced to pulp, not only by the action of said one or more pressurized water nozzles, but also by suction of a water flow containing said waste using a chopper pump.
Further advantageous features and embodiments of the method 3 o according to the invention are set forth in the accompanying dependent claims.
Brief description of the drawings The invention will be better understood with reference to the description and the attached drawing, which shows a practical non-limiting embodiment of the invention. More particularly, in the drawsings:
Fig. 1 shows a schematic side view of the terminal part of a paper production line in which in particular the Yankee drier and the position of the pulper device according to the present invention are visible;
Fig. 2 shows a front view, along II-II, of Fig. 1 of the pulper device;
Figs 3 to 5 show two views and a cross section along the lines 11l-i11, 1V-IV and V-V of Fig. 2; and 1o Fig. 6 shows a diagram of the plant for recycling the waste processed by the pufper.
Detailed description of the preferred embodiment of the invention Fig. 1 illustrates schematically the terminal park of the line for the production of a web or strip of paper, in particular tissue paper. 1 denotes the last wire or the fast felt for conveying the partially dried layer of slurry formed in a manner known per se. The felt 1 is tangential to a Yankee drier 3 so as to transfer the moist web from the external surface of the felt to the external cylindrical surface of the Yankee drier 3 wllich is heated internally. The Yankee drier 3 is embraced by the web over a wide contact 2 0 arc, between the zone of tangential contact with the felt 1 and a doctor or separator blade 5. In a manner known per se the web V, vrhich is dried owing to the heat exchange with the Yankee drier 3, is separated from the cylinder and wound so as to form a reel B intended for further processing.
Below the Yankee drier 3, and in particular in the zone where the doctor blade 5 is arranged, there is a device 7 for collection and recovery of the waste or scrap paper material produced by the Yankee drier 3. The device 7 is shown in isolation and in greater detail in Figs 2 to 5.
Said device comprises a container 9 in the form of a tank or the like, which is elongated in the direction parallel to the axis of the Yankee 3 o drier 3. The container 9 is provided at the top with an upwardly directed inlet opening 11 for collecting the scrap or waste paper material produced by the Yankee drier 3. A first series of nozzles 1 ~ and a second series of - $ -nozzles 15 fior pressurized water are situated along the longitudinal edges of the opening 11. Essentially the two series of nozzles are formed by means of respective pressure ducts, along the axial extension of which the nozzles are distributed. The nozzles are oriented downward and toward the bottom of the container 9, with angles of inclination A and B
relative to the horizontal which are different from each other. Parallel to the direction of the axis of the nozzles of the two series, and therefore substantially parallel to the axes of the two series of jets produced by the nozzles, two walls or surfaces 21, 23 extend, therefore being inclined 1 o downward with angles A and 13 relative to the horizontal. The two surfaces 21, 23 are formed, in the example shown, by two surfaces which extend from the respective series of nozzles 13 or 15 toward the inside of the container, terminating in edges 21A and 23A, respectively. A passage for conveying the water and the refuse paper material toward the bottom of the container 9 is defined between the two edges 21 A, 23A.
The arrangement is such that the waste or scrap paper material which falls or is sucked inside the container 9 intercepts the two series of pressurized-air jets supplied by the two series of nozzles 13, 15. The high-speed water supplied by the nozzles exerts a pulping action on the 2 o intercepted paper material. The incidence, at different angles, of the two series of jets has a cutting effect on the paper material which thus undergoes a first substantial operation involving destruction of the fibrous structure.
The paper material and the water supplied by the nozzles ofi the 2 5 two series 13, 15 are collected on the bottom 9A of the container 9 which is formed inclined downward from one end to the other of the container 9 in the direction of longitudinal extension thereof, i.e. parallel to the direction ofi alignment of the nozzles 13, 15 of the two series.
In the lowermost zone of the bottom 9A of the container 9, an 3 o intake duct 25 of a pump 27 is situated. The latter is a so-called chopper pump, i.e. a pump comprising means able to break up and fragment any solid particles which are suspended in the water flow sucked in through the intake duct. Typically the chopper pump 27 is a pump of the centrifugal type. The refuse paper material which is sucked in by the pump 27 is thus further pulverized.
As shown in particular in the hydraulic fiow diagram shown in Fig.
6, a delivery duct 29 which has a branched recirculation duct 29A extends from the chopper pump 27. The branched duct 29A emerges inside the container 9, at a greater height than the inlet mouth of the intake duct 25 and at the opposite end of the container 9. llVitll this arrangement, a part of the delivery of the chopper pump 27 is rec:irculated directly into the 1 o container 9. The flow which is produced is oriented parallel to the longitudinal direction of the container 9 and therefore facilitates the outflow of the residual paper material along the k~ottom 9A of the container 9 which is in any case inclined downward from 'the outlet of the branched duct 29A toward the inlet mouth of the intake duct 25 of the pump 27. A
valve 30 for regulating the recirculation flow is arranged on the branched duct 29A.
As can be seen from the diagram in F=ig. 6, the main duct 29 extends as far as a second pump 31 which, by means of a delivery duct 33, conveys the flow of water and refuse paper material extracted from the 2 0 container 9 toward a thickening station generically denoted by 35. Here the density of the mixture of water and cellulosE: fiber, obtained from the destruction of the scrap or waste paper material is increased. The substantially purified water which is extracted from the thickening station 35 is discharged by means of a duck 37 into a tank 39 from where it is subsequently recycled. From this tank, water is for example removed (by means of a pump 40) in order to supply the nozzles of the series of nozzles 13, 15, as well as for other utilities, for example for the said thickening station 35, by means of a pump 42 and a duct 44. From an overflow 46 any excess water is discharged from the tank 39 and 3o conveyed away for further purification.
The thickened mixture, i.e. with a richer solid content (having a solid content for example of about 4°/a by weight) is discharged from the thickening station 35 into a second tank 41 and from here recycled by means of conveying to the inflow chamber (not shown) which is supplied with the slurry for production of the web V.
The interior of the container 9 is kept under a vacuum by means of a suction duct 51, the inlet 51 A of which is located below the inclined surface 23A, between the latter and the external wall of the container 9.
Here a closed volume is defined by means of a further separating baffle 53 which has suction openings 55. Air is sucked from the container 9 toward the suction duct 51 through the openings 55. Any fibrous dusts 1 o and/or smaPl droplets of atomized water are also entrained in the air flow.
The suction duct 51 leads into a separator 53, which in the example illustrated is shown as a cyclone separator. Here the liguid andfor solid particles suspended in ~:he air flow are separated and recovered, while the air flow is discharged externally. 55 denotes the suction fan which draws the air through the duct 51.
It is understood that the drawing shnows only one practical embodiment of the invention, the forms and arrangements of which may vary without thereby departing from the scoprr: of the idea forming the basis of the invention. The presence of any reference numbers in the 2 o accompanying claims has solely the purpose of facilitating the reading thereof in the light of the above description and the accompanying drawings and does not limit in any way the scopE; of protection.
Thickening stations are known per se and used in paper production 1 o plants. Examples of thickening stations are described in US-A-5,021,151, US-A-5,186,791, US-A-4,501,040, US-A-4,686,005 and US-A-4,722,793.
Further advantageous features and embodiments of the device according to the invention are indicated in the accompanying dependent claims.
According to a further aspect, an object of the present invention is to provide a method for recycling paper scrap, waste or trimmings, in particular formed around the Yankee drier.
This and further objects and advantages, which will be clear to those skilled in the art from reading of the text which follows, are 2 o essentially obtained by means of a method for recovering and recycling waste paper material supplied from a paper production line, characterized in that said waste is subjected to a pulping action by means of at least one or more pressurized water nozzles so as to produce a mi~cture of water and waste paper material and in that said mixture is recycled.
Advantageously, according to a possible embodiment of the method according to the present invention, the waste is reduced to pulp, not only by the action of said one or more pressurized water nozzles, but also by suction of a water flow containing said waste using a chopper pump.
Further advantageous features and embodiments of the method 3 o according to the invention are set forth in the accompanying dependent claims.
Brief description of the drawings The invention will be better understood with reference to the description and the attached drawing, which shows a practical non-limiting embodiment of the invention. More particularly, in the drawsings:
Fig. 1 shows a schematic side view of the terminal part of a paper production line in which in particular the Yankee drier and the position of the pulper device according to the present invention are visible;
Fig. 2 shows a front view, along II-II, of Fig. 1 of the pulper device;
Figs 3 to 5 show two views and a cross section along the lines 11l-i11, 1V-IV and V-V of Fig. 2; and 1o Fig. 6 shows a diagram of the plant for recycling the waste processed by the pufper.
Detailed description of the preferred embodiment of the invention Fig. 1 illustrates schematically the terminal park of the line for the production of a web or strip of paper, in particular tissue paper. 1 denotes the last wire or the fast felt for conveying the partially dried layer of slurry formed in a manner known per se. The felt 1 is tangential to a Yankee drier 3 so as to transfer the moist web from the external surface of the felt to the external cylindrical surface of the Yankee drier 3 wllich is heated internally. The Yankee drier 3 is embraced by the web over a wide contact 2 0 arc, between the zone of tangential contact with the felt 1 and a doctor or separator blade 5. In a manner known per se the web V, vrhich is dried owing to the heat exchange with the Yankee drier 3, is separated from the cylinder and wound so as to form a reel B intended for further processing.
Below the Yankee drier 3, and in particular in the zone where the doctor blade 5 is arranged, there is a device 7 for collection and recovery of the waste or scrap paper material produced by the Yankee drier 3. The device 7 is shown in isolation and in greater detail in Figs 2 to 5.
Said device comprises a container 9 in the form of a tank or the like, which is elongated in the direction parallel to the axis of the Yankee 3 o drier 3. The container 9 is provided at the top with an upwardly directed inlet opening 11 for collecting the scrap or waste paper material produced by the Yankee drier 3. A first series of nozzles 1 ~ and a second series of - $ -nozzles 15 fior pressurized water are situated along the longitudinal edges of the opening 11. Essentially the two series of nozzles are formed by means of respective pressure ducts, along the axial extension of which the nozzles are distributed. The nozzles are oriented downward and toward the bottom of the container 9, with angles of inclination A and B
relative to the horizontal which are different from each other. Parallel to the direction of the axis of the nozzles of the two series, and therefore substantially parallel to the axes of the two series of jets produced by the nozzles, two walls or surfaces 21, 23 extend, therefore being inclined 1 o downward with angles A and 13 relative to the horizontal. The two surfaces 21, 23 are formed, in the example shown, by two surfaces which extend from the respective series of nozzles 13 or 15 toward the inside of the container, terminating in edges 21A and 23A, respectively. A passage for conveying the water and the refuse paper material toward the bottom of the container 9 is defined between the two edges 21 A, 23A.
The arrangement is such that the waste or scrap paper material which falls or is sucked inside the container 9 intercepts the two series of pressurized-air jets supplied by the two series of nozzles 13, 15. The high-speed water supplied by the nozzles exerts a pulping action on the 2 o intercepted paper material. The incidence, at different angles, of the two series of jets has a cutting effect on the paper material which thus undergoes a first substantial operation involving destruction of the fibrous structure.
The paper material and the water supplied by the nozzles ofi the 2 5 two series 13, 15 are collected on the bottom 9A of the container 9 which is formed inclined downward from one end to the other of the container 9 in the direction of longitudinal extension thereof, i.e. parallel to the direction ofi alignment of the nozzles 13, 15 of the two series.
In the lowermost zone of the bottom 9A of the container 9, an 3 o intake duct 25 of a pump 27 is situated. The latter is a so-called chopper pump, i.e. a pump comprising means able to break up and fragment any solid particles which are suspended in the water flow sucked in through the intake duct. Typically the chopper pump 27 is a pump of the centrifugal type. The refuse paper material which is sucked in by the pump 27 is thus further pulverized.
As shown in particular in the hydraulic fiow diagram shown in Fig.
6, a delivery duct 29 which has a branched recirculation duct 29A extends from the chopper pump 27. The branched duct 29A emerges inside the container 9, at a greater height than the inlet mouth of the intake duct 25 and at the opposite end of the container 9. llVitll this arrangement, a part of the delivery of the chopper pump 27 is rec:irculated directly into the 1 o container 9. The flow which is produced is oriented parallel to the longitudinal direction of the container 9 and therefore facilitates the outflow of the residual paper material along the k~ottom 9A of the container 9 which is in any case inclined downward from 'the outlet of the branched duct 29A toward the inlet mouth of the intake duct 25 of the pump 27. A
valve 30 for regulating the recirculation flow is arranged on the branched duct 29A.
As can be seen from the diagram in F=ig. 6, the main duct 29 extends as far as a second pump 31 which, by means of a delivery duct 33, conveys the flow of water and refuse paper material extracted from the 2 0 container 9 toward a thickening station generically denoted by 35. Here the density of the mixture of water and cellulosE: fiber, obtained from the destruction of the scrap or waste paper material is increased. The substantially purified water which is extracted from the thickening station 35 is discharged by means of a duck 37 into a tank 39 from where it is subsequently recycled. From this tank, water is for example removed (by means of a pump 40) in order to supply the nozzles of the series of nozzles 13, 15, as well as for other utilities, for example for the said thickening station 35, by means of a pump 42 and a duct 44. From an overflow 46 any excess water is discharged from the tank 39 and 3o conveyed away for further purification.
The thickened mixture, i.e. with a richer solid content (having a solid content for example of about 4°/a by weight) is discharged from the thickening station 35 into a second tank 41 and from here recycled by means of conveying to the inflow chamber (not shown) which is supplied with the slurry for production of the web V.
The interior of the container 9 is kept under a vacuum by means of a suction duct 51, the inlet 51 A of which is located below the inclined surface 23A, between the latter and the external wall of the container 9.
Here a closed volume is defined by means of a further separating baffle 53 which has suction openings 55. Air is sucked from the container 9 toward the suction duct 51 through the openings 55. Any fibrous dusts 1 o and/or smaPl droplets of atomized water are also entrained in the air flow.
The suction duct 51 leads into a separator 53, which in the example illustrated is shown as a cyclone separator. Here the liguid andfor solid particles suspended in ~:he air flow are separated and recovered, while the air flow is discharged externally. 55 denotes the suction fan which draws the air through the duct 51.
It is understood that the drawing shnows only one practical embodiment of the invention, the forms and arrangements of which may vary without thereby departing from the scoprr: of the idea forming the basis of the invention. The presence of any reference numbers in the 2 o accompanying claims has solely the purpose of facilitating the reading thereof in the light of the above description and the accompanying drawings and does not limit in any way the scopE; of protection.
Claims (27)
1. Pulper device for waste paper material, characterized in that it comprises:
- a container (9) for collecting said waste, having are 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 the waste from said container.
- a container (9) for collecting said waste, having are 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 the waste from said container.
2. Device according to claim 1, characterized in that it comprises a first series (11) of pressurized water nozzles and a second series (13) of pressurized water nozzles, the jets produced by the nozzles of the first series and the nozzle jets produced by the second series having trajectories which intersect in a zone where said waste falls.
3. Device according to claim 2, characterized in that said nozzles have trajectories with different inclinations.
4. Device according to claim 2 or 3, characterized in that two inclined surfaces (21, 23) for guiding the jets produced by the nozzles are associated with said first series (11) and said second series (13) of nozzles.
5. Device according to claim 4, characterized in that said inclined surfaces are oriented approximately parallel to the trajectory of the jets produced by the respective nozzles.
6. Device according to claim 4 or 5, characterized in that each of said surfaces extends from the respective series of nozzles as far as a respective terminal edge (21A, 23A), the terminal edges of said two surfaces delimiting a passage for conveying the water and the waste paper material.
7. Device according to claim 4, 5 or 6, characterized in that said surfaces are flat.
8. Device according to one or more of the preceding claims, characterized in that said container has an elongated longitudinal extension, the inlet opening extending in the longitudinal direction of extension of said container.
9. Device according to one or more of claims 2 to 8, characterized in that said container has an elongated nipper opening, parallel to which said first and said second series of nozzles extend.
10. Device according to one or more of the preceding claims, characterized in that said first pump (27) is a chopper pump.
11. Device according to one or more of the preceding claims, characterized in that it comprises a recirculation duct (29A) between said first pump (27) and the container (9), by means of which a part of the flow sucked in by said first pump is recirculated inside said container.
12. Device according to claim 11, characterized in that the outlet of said recirculation duct (29A) is situated in a position approximately opposite an intake opening (25) of said first pump.
13. Device according to at least claims 8 and 12, characterized in that the outlet of said recirculation duct (29A) and the intake opening of said first pump are arranged approximately at the ends of the elongated longitudinal extension of said container.
14. Device according to claim 12 or 13, characterized in that the bottom of said container is inclined downwardly and from the outlet of said recirculation duct toward the intake opening of said first pump.
15. Device according to one or more of the preceding claims, characterized in that said container is connected to a suction duct (51) which sucks air from inside said container (9).
16. Device according to at least claims 4 and 15, characterized in that said suction duct (51) has suction openings (55) arranged underneath at least one of said two inclined surfaces.
17. Device according to claim 15 or 16, characterized in that said suction duct is connected to a separator (53) for separating air from solid and/or liquid particles entrained in the air flow.
18. Device according to one or more of the preceding claims, characterized in that it comprises a thickening station (35) to which at least partly the mixture of water and waste paper material sucked by said first pump is conveyed and inside which the solid content of the mixture is increased, eliminating therefrom a part of the water content.
19. Device according to claim 18, characterized in that a second pump (31), which conveys the flow sucked by said first pump, less the recirculation flow, toward said thickening station (35), is arranged along the delivery duct of said first pump (27).
20. Device according to claim 18 or 19, characterized in that the mixture leaving said thickening station is conveyed to a container for subsequent conveying to a headbox associated with the paper production line and the water separated from said mixture is recycled.
21. Method for recovering and recycling waste paper material supplied from a paper production line, characterized in that said waste is subjected to a pulping action by means of one or more pressurized water jets so as to produce a mixture of water and waste paper material and in that said mixture is recycled.
22. Method according to claim 21, characterized in that said waste is reduced to pulp, not only by the action of said one or more pressurized water nozzles, but also by suction of a water flow containing said waste using a chopper pump.
23. Method according to claim 21 or 22, characterized in that said waste is passed between a first and a second series of pressurized water nozzles, the jets produced by said first and said second series of nozzles intersecting each other.
24. Method according to one or more of the preceding claims, characterized in that said waste is sucked into a container kept under a vacuum.
25. Method according to claim 24, characterized in that said container is kept under a vacuum by sucking air from inside it to underneath a surface guiding one or more jets of water produced by said pressurized water nozzles.
26. Method according to claim 25, characterized in that an air flow sucked from said container is generated, and water and any solid particles are separated from said flow, said water and said solid parts being recycled.
27. Method according to one or more of claims 21 to 26, characterized in that the solid-matter content of said mixture is increased by means of partial separation of the water contained therein and in that the mixture thus treated is introduced again into the paper production cycle and the separated water is recycled into the paper production plant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP02425495A EP1386998B1 (en) | 2002-07-31 | 2002-07-31 | Pulper and method for the recovery of paper production waste |
| EP02425495.5 | 2002-07-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2436379A1 true CA2436379A1 (en) | 2004-01-31 |
Family
ID=30011314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002436379A Abandoned CA2436379A1 (en) | 2002-07-31 | 2003-07-30 | Pulper device for the recovery of paper production waste, plant comprising said device and associated method for recovery of the waste |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20040094276A1 (en) |
| EP (1) | EP1386998B1 (en) |
| AT (1) | ATE294275T1 (en) |
| CA (1) | CA2436379A1 (en) |
| DE (1) | DE60203897T2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7203976B1 (en) * | 2004-07-16 | 2007-04-17 | Zoeller Company | Floor level waste pumping system for toilets |
| GB2468481A (en) * | 2009-03-06 | 2010-09-15 | Vernacare Ltd | Macerator using high pressure water jets to macerate |
| US20100319116A1 (en) * | 2009-06-23 | 2010-12-23 | William Schmidt | Waste Pumping System |
| EP2474666A1 (en) | 2011-06-21 | 2012-07-11 | Metso Paper Inc. | Arrangement for a fiber web production line |
| CN111005249B (en) * | 2019-12-24 | 2020-10-30 | 张亚勤 | Pulping system for producing paper products by recycling waste paper |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2667106A (en) * | 1951-09-13 | 1954-01-26 | Black Clawson Co | Paper machinery |
| US2696766A (en) * | 1952-08-21 | 1954-12-14 | Black Clawson Co | Paper machinery |
| US3201066A (en) * | 1962-11-29 | 1965-08-17 | Bolton John W & Sons Inc | Machine and method for disposing of broke |
| US3417933A (en) * | 1965-07-12 | 1968-12-24 | Black Clawson Co | Pulper |
| US3973866A (en) * | 1975-01-02 | 1976-08-10 | Vaughan Co., Inc. | Centrifugal chopping slurry pump |
| US4448638A (en) * | 1980-08-29 | 1984-05-15 | James River-Dixie/Northern, Inc. | Paper webs having high bulk and absorbency and process and apparatus for producing the same |
| US4458845A (en) * | 1982-07-16 | 1984-07-10 | Marcalus James A | Pulping apparatus |
| DK0536320T3 (en) * | 1990-06-29 | 1995-02-20 | Procter & Gamble | Paper making tape and method for making same using different lighting transmission technique |
| US5234172A (en) * | 1991-02-01 | 1993-08-10 | The Black Clawson Company | High pressure water jet comminuting |
| US5464161A (en) * | 1994-09-30 | 1995-11-07 | The United States Of America As Represented By The Secretary Of The Navy | Solid waste pulper |
| US6086714A (en) * | 1997-10-24 | 2000-07-11 | Praxair Technology, Inc. | Process for adjusting the alkalinity of pulp slurry in a broke pulper using carbon dioxide |
| FI104646B (en) * | 1998-07-03 | 2000-03-15 | Valmet Corp | Device and method for conducting a paper / cardboard web to a pulp solver |
| US6187139B1 (en) * | 1999-07-13 | 2001-02-13 | Fort James Corporation | Wet creping process |
| US6358367B1 (en) * | 2000-02-01 | 2002-03-19 | Voith Sulzer Paper Technology North America, Inc. | Pulping system for a paper machine |
-
2002
- 2002-07-31 EP EP02425495A patent/EP1386998B1/en not_active Expired - Lifetime
- 2002-07-31 DE DE60203897T patent/DE60203897T2/en not_active Expired - Lifetime
- 2002-07-31 AT AT02425495T patent/ATE294275T1/en not_active IP Right Cessation
-
2003
- 2003-07-30 US US10/630,962 patent/US20040094276A1/en not_active Abandoned
- 2003-07-30 CA CA002436379A patent/CA2436379A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| ATE294275T1 (en) | 2005-05-15 |
| EP1386998B1 (en) | 2005-04-27 |
| US20040094276A1 (en) | 2004-05-20 |
| EP1386998A1 (en) | 2004-02-04 |
| DE60203897D1 (en) | 2005-06-02 |
| DE60203897T2 (en) | 2006-01-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |