paper industry process description. 2 summary- part 1. paper paste generation paper industry process...

PAPER INDUSTRY

PROCESS DESCRIPTION

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SUMMARY- PART 1. PAPER PASTE GENERATION

Paper IndustryPROCESS DESCRIPTION

1. Raw material

2. First paper separation

3. Second paper separation

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SUMMARY- PART 2. PAPER PASTE TREATMENT

1. First homogenizing of paper paste

2. Second homogenizing of paper paste

3. Purifying of paper paste

4. Filtering and rejection of paper paste

5. Fine filtering of paper paste

6. First thickness of paper paste

7. Recovery of fibers


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SUMMARY- PART 2. PAPER PASTE TREATMENT

8. Refinement of paper paste

9. Grid purifying of paper paste

10. Final homogenizing of paper paste

11. Transferring to the machine headpiece of paper paste

12. Train of aspiration, drying, pressing and reeling of paper

13. Reels cut


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Paper Industry: Process DescriptionPAPER PASTE GENERATION

PART 1

1

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Paper Industry – Process DescriptionPAPER PASTE GENERATION

Raw material is ‘tetra-brick’ remains basically. This implies a separation process:» On the one hand paper.» On the other hand aluminium and plastic.

Raw material cost is almost zero. Aluminium and plastic remains are packed, liberated from water and burned to generate steam that will be used to dry the paper.

1. RAW MATERIAL

» Raw material entry » Aluminium and plastics remains accumulated

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The bales of raw material are transported by transport bands up to the pulpers. Over there water is added and starts the crushing and separation. The grid is about 12mm.

The screw and the blades crush and spin, and so starts the milling of material. Then, the added water will be extracted by a suction pump.

2. FIRST PAPER SEPARATION

» Manufacturing paper. Plastic burning » Paper dissolution

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In this way, first separation is realized, trying not to broke the aluminium.

At the end, we managed to empty the system that will be ready again for receiving new bales of material.

2. FIRST PAPER SEPARATION

» Pulper emptying » Pulper empty

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Remains pass to the trommel from the drainpipe of the pulper, where spin during 5min. (approx) to remove more water.Then, the rotation direction is inverted and transport bands are driven, retiring the remains (alu. and plastics).

Drained water is elevated towards a tank by pumps for this purpose.

3. SECOND PAPER SEPARATION

» Drying trommel » Trommel drying out pumps

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Paper Industry: Process DescriptionPAPER PASTE TREATMENT

PART 2

2

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Paper Industry – Process DescriptionPAPER PASTE TREATMENT

There are different trommels, but all paper paste is impelled towards two tanks or tubs. The percentage of paper in this paste is about 3g/litre. It is very liquid.

A pump system at the input of the tanks allows mixing all received past in the tanks themselves.

1. FIRST HOMOGENIZING OF PAPER PASTE

» Output trommel tank » Impulsing pumps at output trommel

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After these two deposits, there is a third cement tank that receives the mixture of the pastes contained in the previous tubs.

The process is executed with two pumps at the output of both tanks.

It is necessary to take the quality of each paper paste into account to dose the needed amount from each tank, with the purpose that the mixture of the third tank fulfils with the required specifications.

2. SECOND HOMOGENIZING OF PAPER PASTE

» Second homogenizing tank

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After paste is homogenized, this one is subjected to a filtering or purifying to retire small remains that still are present (staples, food remains, …).

This is realized in the centrifuge purifier: the light things are elevated (paper) and the heavy things are deposited (remains).

3. PURIFYING OF PAPER PASTE

» Centrifuge purifiers

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From centrifuge purifiers, all of the mixture pass to a level box, thanks to the impulsing realized by a pump.

The process goes on from this level box to the ‘cibersorter’. In this one a new filtering of present elements is realized, with a grid lower than 1.5mm.

4. FILTERING AND REJECTION OF PAPER PASTE

» Level box

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In the ‘cibersorter’ filtering there is a rejection generated by this grid exactly.

This rejection part is recirculated towards the ‘rejectsorter’ where suffers a low sieve and is sent to the ‘cibersorter’ again.

The ‘rejectsorter’ manages to separate pieces of paper that are not crushed properly, and plastic remains. All this will be incinerated.

4. FILTERING AND REJECTION OF PAPER PASTE

» Rejectsorter

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At the ‘cibersorter’ output, the part of the paste that are not rejected, is impelled to another level box, and from there pass to a finer filtering realized by the cyclonic purifiers or ‘cleaners’.

In this case, they are 4 different purifiers, with their 4 driving motors.

5. FINE FILTERING OF PAPER PASTE

» Cyclonic purifiers

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From the cleaners, the paste pass to the ‘variosplit’, where the water starts to get out, and the paste makes thickness.For this, the mixture is sent out through different spurts (linear shower) over a cloth or felt.

The cloth is moved by a rollers (approx. speed 400m/min).The water fog corresponds with the area where the linear shower is expelled over the cloth.

6. FIRST THICKNESS OF PAPER PASTE

» Variosplit » Variosplit detail

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The water picked up in the variosplit goes to the purifier of the plant and there follows the normal process of primary and secondary decantation. Before that, this water suffers a process of fibers recovery and overturning inside a deposit. For this, a system of three pumps is used: one pump injects the water at constant speed, other pump controls the level of the output tank and the last one is used as a spare. The paste is picked up in other tank. From this one, the paste will pass to the following stage.

7. RECOVERY OF FIBERS

» Variosplit sprinkler » Tank previous to the refinement

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The paste pass to a refinement stage. This stage tries to break the film that involves the paste which will make difficult its later framework in the table. ‘Blowing up’ this film, micro fibers that will link better are generated.

For this, it is used a machine consisted of discs that put the proper pressure. The motor of this machine is controlled by current signal, since its rating is about 600kW.

8. REFINEMENT OF PAPER PASTE

» Refinement » Refinement motor

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After the refinement output, the paste suffers a new purification process called grid purifying.

In this purifiers there is an internal cylinder sleeve with grids (size lower than 0.2mm) and a propeller that producing the movement by forcing the material to pass and separating the remains.

9. GRID PURIFYING OF PAPER PASTE

» Grid purifying

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At the output of the previous stage, there are two tanks where a new homogenizing of the paste is realized.To do that, there are two agitators and a transferring pump before passing to the grammage pump.

The paste is agitated and transferred from a deposit to the another one to obtain the proper consistency.Finally, the paste will pass to the pump that will define the grammage for the paper finishing (higher or lower thickness).

10. FINAL HOMOGENIZING OF PAPER PASTE

» Tanks at machine headpiece

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Before seeing the paper paste again over the final table, a dilution process is produced. This is produced in the centrifuge purifier called ‘giroclean’. For this, two pumps are used:» Pump of first dilution: receives the material from the grammage pump.» Pump of second dilution: sends the material from the giroclean up to the distribution box.

11. TRANSFERRING TO THE MACHINE HEADPIECE OF PAPER PASTE

» Distribution box » Paper forming

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In the distribution box the paste goes out through a grid of 12cm approx.The overturning of the paste is controlled according to the speed of the drop by drop dried out cloth. In this way, the amount of paste is dosed according to the paper gammage.Thanks to the cloth properties, water of the paste is dried out drop by drop and at the end of the way it will be already dry.

11. TRANSFERRING TO THE MACHINE HEADPIECE OF PAPER PASTE

» Distribution box

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From this point, there is a train consisted of 13 rollers with their corresponding motors. All of the motors are driven by speed and follows a pre-defined reference.Then, there are two vacuum systems to aspirate the water of the paper and the felts. After that, there is a pressing area to remove more water to the paper and also there is a steam-dried area before reeling the dry paper.

12. TRAIN OF ASPIRATION, DRYING, PRESSING AND REELING OF PAPER

» Rollers train 01 » Rollers train 02

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The low vacuum allows removing water to the felts when passing the table, through the aspiration boxes.The high vacuum actuates through the rest of cylinders that are hollow and perforated. As cylinders press, the water comes into them where is aspirated by the generated vacuum.


» Rollers train 01 » Aspiration boxes

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After this, it arrives the steam-dried area.

When burning the plastic, it is used to generate energy and steam that is driven here and distributed for the ventilation motors of this part of the machine in an uniform way.


» Rollers train 01 » Aspiration boxes

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When process is finished, the paper is ready to be reeled by the last roller or Pope.There is a mechanism that allows putting and fixing an empty shaft, an adhesive strip is thrown from one extreme to the other. This strip cuts the paper sheet and hooks the cut paper at the same time. In this way, that roller downs and the reeling goes on over a new shaft.Then, the previous reel can be already retired.


» Rollers train output » Paper finished

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Once retired the reel, this one suffers a customized process.

There is an auxiliary table with several blades and grid cylinders that allow unreeling the paper and cutting it to generate new reels with a required width for each case. See manufacturers.

13. REELS CUT

» Reels treatment

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Criteria of use for Power Electronics DevicesVARIABLE SPEED DRIVES & SOFTSTARTERS3

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Paper IndustryCRITERIA OF USE FOR POWER ELECTRONICS DEVICES

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» INPUT TRANSPORT BANDS: Softstarter or Variable Speed Drive» Ratings oscillate around 7.5 – 11kW approximately

Recommended equipments:» V5 Series – Frame 1» SD250 Series» SD450 Series

[ POWER ELECTRONICS EQUIPMENTS USE JUSTIFICATION ][ POWER ELECTRONICS EQUIPMENTS USE JUSTIFICATION ]

1. ACTUATORS FOR RAW MATERIAL

Allows continuous operating according to the production requirements avoiding unnecessary startings and stoppings.

Speed control. Manufacturing optimization.

Paper Industry – Part 1 : Paper Paste GenerationCRITERIA OF USE FOR POWER ELECTRONICS DEVICES

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» PULPER SCREW (250 – 315kW approx.): Variable Speed Drive

Recommended equipments:» SD700 Series – Frame 6


2. ACTUATORS FOR FIRST PAPER SEPARATION

While milling process is realized in the pulper, we operates at lower speed (for example, 40Hz), with the objective that aluminum (recycling) is not broken.

When this process is finished (elapsed time depends on the pulper capacity, groups of 1800kg of dry paper usually), speed is increased (for example, 50Hz) to start the vacuum process that is interesting to do it faster.Without variable speed drive is not possible to regulate several operating speeds.


» SUCTION PUMPS (55kW approx.): Softstarter

Recommended equipments:» V5 Series – Frame 2

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» INPUT TRANSPORT BANDS: Softstarter or Variable Speed Drive» Ratings oscillate around 7.5 – 11kW approximately

Recommended equipments:» V5 Series – Frame 1» SD250 Series» SD450 Series


3. ACTUATORS FOR SECOND PAPER SEPARATION

Allows continuous operating according to the production requirements avoiding unnecessary startings and stoppings.

Speed control. Manufacturing optimization.


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» TROMMEL (30kW approx.): Softstarter or Variable Speed Drive» ELEVATION PUMPS (22.5kW approx.): Softstarter or Variable Speed Drive

Recommended equipments:» V5 Series – Frame 1» SD450 Series


3. ACTUATORS FOR SECOND PAPER SEPARATION

In the trommel there is a hydraulic system that allows the regulation in the same way that the softstarter protects and drives the motor correctly.Using the proper variable speed drive, long life of specific mechanical components (reducer, …) will be extended.


Regarding to the elevation, the variable speed drive will achieve a system optimization again, and allows saving the 8-9 startings per hour suffered by those motors now.Additionally, it allows closing the loop with the level detector of the tank that receives impelled water to keep it full, but avoiding overflows. (See photos).

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» TWO PUMPS FOR AGITATORS (15kW approx.): Softstarter or Variable Speed Drive

Recommended equipments:» V5 Series – Frame 1» SD450 Series


1. ACTUATORS FOR FIRST HOMOGENIZING OF PAPER PASTE

The qualities of the trommels are different and the collection is centered in two tanks. For this, it is necessary to homogenize the paste, so that both tanks contain paste with the same characteristics.

Paper Industry – Part 2 : Paper Paste TreatmentCRITERIA OF USE FOR POWER ELECTRONICS DEVICES

Two first pumps agitate the mixture at constant speed. For this reason, softstarters are proper, always considering that a variable speed drive regulates the speed according to the amounts that are received.

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» TWO HOMOGENIZING PUMPS (55kW approx.): Softstarter or Variable Speed Drive

Recommended equipments:» V5 Series – Frame 2» SD450 Series» SD700 Series (low power)


2. ACTUATORS FOR SECOND HOMOGENIZING OF PAPER PASTE

The mixture has been agitated by two first motors, but now, it is necessary to mixture the content of they both. For this, the flow is controlled and by setting the desired percentages it manages to overturn the needed amounts to the third tank.


The pumps which control the homogenizing process, control the flows that are sent from the trommels with this purpose exactly.

Each variable speed drive receives the overturning reference (65% + 35%, for example) and this one becomes its speed reference.

Variable speed drives allows closing a control loop that manages to do this. Otherwise, it is not possible.Additionally, it is possible to control the level of the third tank.

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» TWO IMPULSING PUMPS: Softstarter» Ratings oscillate around 30kW approximately



3. ACTUATORS FOR PURIFYING OF PAPER PASTE

Paper paste is impelled at constant speed; pipes and purifiers shape realize the rest, achieving sedimentation of the first small-sized remains.


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» CIBERSORTER (75kW approx.): Softstarter or Variable Speed Drive» REJECTSORTER (55kW approx.): Softstarter or Variable Speed Drive

Recommended equipments:» V5 Series – Frame 2» SD450 Series» SD700 Series – Frame 4


4. ACTUATORS FOR FILTERING AND REJECTION OF PAPER PASTE

As in previous stage the pasted is being impelled at constant speed, softstarters continues with the process.


The use of variable speed drive allows a speed control with the consequent energy saving.

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Recommended equipments:» SD450 Series» SD700 Series – Frame 4


5. ACTUATORS FOR FINE FILTERING OF PAPER PASTE

For cleaners pumps are always primed y air bags do not enter, there is an auxiliary water tank. This one keeps constant the level and needed water to keep the priming is taken from this tank.


In this way, variable speed drives realize a pressure control in closed loop, managing to keep desired reference for each one of them, regulating speed every time.

» CLEANER PUMP 1 (90kW approx.): Variable Speed Drive» CLEANER PUMP 2 (55kW approx.): Variable Speed Drive» CLEANER PUMP 3 (22kW approx.): Variable Speed Drive» CLEANER PUMP 4 (15kW approx.): Variable Speed Drive

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Recommended equipments:» SD450 Series» SD700 Series – Frame 4


6. ACTUATORS FOR FIRST THICKNESS OF PAPER PASTE

Motor that moves the cloth is driven through a variable speed drive controlled by encoder, so system always knows the real speed of the motor. The reference (for example, 400m/min) will be kept by the speed control.


Thanks to that we can achieve the efficiency of the machine is optimum according to the different types of paper that is being produced.Motor of watering can is also controlled by variable speed drive because the pressure is regulated. So, we achieve that any output hole of the shower is obturated. This would increase the pressure in the free holes and the cloth would be probably broken in the area where the pressure is too high.

» VARIOSPLIT CLOTH MOTOR (75kW approx.): Variable Speed Drive» VARIOSPLIT SPRINKLER MOTOR (15kW approx.): Variable Speed Drive

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» THREE PUMPS FOR WATER RECOVERY (90kW approx.): Softstarter or Variable Speed Drive

Recommended equipments:» V5 Series – Frame 2» SD700 Series – Frame 4


7. ACTUATORS FOR RECOVERY OF FIBERS

The system consists of a couple of operative pumps and other one as a spare. One of them injects water at constant speed. There is not any control and for this reason a started is used.

The second one is driven by a variable speed drive. Thanks to this, it can close a control loop with the level of the tub that is being filled, and the speed of this pump changes to avoid overflows.Therefore, this option is applicable to the first pump and so, only the second one suffers.


Recommended equipments:» V5 Series – Frame 1» SD450 Series» SD700 Series (low power)

» ONE PUMP FOR PASTE RECOVERY (30kW approx.): Softstarter or Variable Speed Drive

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» REFINEMENT MOTOR (600kW approx.): Softstarter



8. ACTUATORS FOR REFINEMENT OF PAPER PASTE

Small motor realizes the approximation of discs. NOTE: Sometimes, the refinement is realized with blades and softstarters. For modifying the refinement type is necessary to replace the blades. If the possibility of mounting a group of blades simultaneously exists, then a drive would allow controlling it without replacing them.


» CONTROL MOTOR (2.5kW approx.): Variable Speed Drive

Recommended equipments:» SD450 Series

Big motor keeps spinning discs at constant speed. This speed is very near the maximum current consumption.

Analogue output proportional to that current is sent from the softstarter up to the drive so that this one actuates over the small motor and allows bringing near more or less the discs, producing a higher or lower refinement.

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» TWO PURIFIERS (75kW approx.): Softstarter or Variable Speed Drive» ONE PURIFIER (55kW approx.): Softstarter or Variable Speed Drive

Recommended equipments:» V5 Series – Frame 2» SD450 Series» SD700 Series – Frame 4


9. ACTUATORS FOR GRID PURIFYING OF PAPER PASTE

The use of variable speed drive is recommended to modify the motor speed according to the received paste, with the consequent energy saving.


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» TWO AGITATORS (22kW approx.): Softstarter» TRANSFERRING PUMP (22kW approx.): Softstarter



10. ACTUATORS FOR FINAL HOMOGENIZING OF PAPER PASTE

For the agitators and transferring pump we can use softstarters, since most of the pumpings are realized at constant speed.

For the grammage pump, the use of a drive is obvious since this one doses continuously the amount of paste according to the grammage that will be had by finished paper.


Recommended equipments:» SD450 Series

» GRAMMAGE PUMP (15kW approx.): Variable Speed Drive

Nevertheless, the installation of a drive could be a great improvement again, so that these pumps would be controlled by the level signal of machine headpiece tubs.

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» FIRST DILUTION PUMP (55kW approx.): Softstarter» CENTRIFUGE PURIFIER (55kW approx.): Softstarter» SECOND DILUTION PUMP (90W approx.): Variable Speed Drive

Recommended equipments:» V5 Series – Frame 2» SD700 Series – Frame 4


11. ACTUATORS FOR TRANSFERRING TO THE MACHINE HEADPIECE OF PAPER PASTE

Centrifuge purifier has a current peak very high. For this, the use of softstarter is needed to protect the motor.However, if the system clutch is treated properly, it is possible to improve the operation and optimize the current consumption at the startings by installing a drive.

Regarding to the second dilution pump, the use of variable speed drive is necessary to be able to control, by motorized potentiometer, the column of the distribution box, this is, it is necessary to keep the pressure constant.


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Recommended equipments:» SD450 Series» SD700 Series – Frames 4, 5 and 6


12. ACTUATORS FOR TRAIN OF ASPIRATION, DRYING, PRESSING AND REELING OF PAPER

The entire system must be aligned perfectly, the rollers must be rectified correctly and above all controlled, so that the paper does not bend, or creases, or twists or breaks.This control is realized by the variable speed drives connected to the network and controlled from PLC. So, PLC is able to calculate the needed increments of speed between one roller and the next one to keep tight the paper, but without breaking it.


If we consider that as the reel dimensions change, the speed must be adjusted, the process must be conceived as a permanent change of speed, realizing a vector control in closed loop with encoder.

» TWO MOTORS FOR FELTS (200kW approx.): Variable Speed Drive» ONE MOTOR FOR FELTS (132kW approx.): Variable Speed Drive» TEN MOTORS FOR CYLINDERS (75kW approx.): Variable Speed Drive

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» THREE PUMPS FOR LOW VACUUM (132kW approx.): Softstarter or Variable Speed Drive» THREE PUMPS FOR HIGH VACUUM (200kW approx.): Softstarter or Variable Speed Drive» ONE PUMP FOR HIGH VACUUM (75kW approx.): Softstarter or Variable Speed Drive

Recommended equipments:» V5 Series – Frames 2 and 3» SD450 Series» SD700 Series – Frames 4, 5 and 6


12. ACTUATORS FOR TRAIN OF ASPIRATION, DRYING, PRESSING AND REELING OF PAPER

Control of the motors is realized by softstarters operating at constant mode, nevertheless, if variable speed drives are used, the aspiration speed could be modified according to the humidity, the paper grammage, the amount of the paper, etc…


Thanks for your attention

PresentationPAPER INDUSTRY: Process Description

RealizedPilar Navarro

OrganizedMarketing Department

www.power-electronics.com©2006 Power Electronics, S.L.

paper industry process description. 2 summary- part 1. paper paste generation paper industry process...

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