Top former is a part of the PM wire part. It is installed between the under-pressure and suction boxes, approximately in the second third of the wire table. Its most important part is a three-chamber suction box with different under-pressure values in particular chambers. Through separators this suction box is connected to the vacuum system. On the bearing structure, type cantilever, there are driving roll, guide roll with positioning, wire run regulator, wire stretching device, spraying showers and wire cleaning system installed. All the rolls are provided with doctors. Under the bottom wire, on the bearing structure, there are white water trays with discharge branches installed and used for splashing. The top former itself is completed also with service bridges. It is used particularly in new and reconstructed PM wire sections with operating speeds up to 1.500 resp. 1.600 m/min. Dryness on the bottom wire is 10-12%.
The most important part of the top former is its suction box with diverse vacuum capacity and gradually increasing under- pressure values.
Under the suction box of top former and under the bottom wire there is a forming box installed with height-adjustable and pneu-matically controlled bars in order to improve formation of the paper on the wire. Behind the forming chamber there is a suction box keeping the paper web on the bottom wire in the place of division of the top and bottom wire.
Construction design and machine safety are in compliance with EU and EAC standards.
| Technical Parameters | ||
|---|---|---|
| Max. Paper width | mm | 7500 |
| Max. Working speed | m/min | 1500 |
| Max. Production range | g/m2 | 35 - 200 *) |
| Dewatering (% flow rate from headbox) | % | 30 - 60 *) |
* according to the grade of produced paper
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Category
Paper MachineSection
IndustrialPaper/CulturalPaper/SpecialtyPaper