Method and a machine for producing a structured fibrous web of paper
First Claim
1. A method of producing a structured fibrous web of paper, the method comprising the steps of:
- forming a fibrous web and conveying the formed fibrous web on a water receiving felt to a dewatering nip formed by a first press unit and a second press unit and where an endless belt is passed through the nip together with the fibrous web and the water receiving felt, the endless belt having a side which is covered by polyurethane and which contacts the fibrous web in the dewatering nip;
after the dewatering nip, conveying the fibrous web by the endless belt to an endless textured fabric which is permeable to air and to which the web is transferred from the endless belt, the textured fabric running at a lower speed than the endless belt; and
after the transfer to the textured fabric, conveying the fibrous web by the textured fabric to a drying cylinder,wherein the web is transferred from the endless belt to the textured fabric in a transfer nip, the transfer nip being formed between a first transfer nip roll that lies within the loop of the endless belt and a second transfer nip roll which is a suction roll located within the loop of the textured fabric, the transfer nip having a length in the machine direction which is in the range of 5 mm-40 mm.
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0 Petitions
Accused Products
Abstract
The invention relates to a method of producing a structured fibrous web of paper. The method comprises forming a fibrous web and conveying the formed fibrous web on a water receiving felt (5) to a dewatering nip. An endless belt (11) with a polyurethane surface is passed through the nip together with the fibrous web and the water receiving felt (5). After the dewatering nip, the fibrous web is conveyed by the endless belt (11) to an endless textured fabric (12) which is permeable to air and to which the web is transferred from the endless belt (11) in a transfer nip. The textured fabric (12) rans at a lower speed than the endless belt (11). After the transfer to the textured fabric (12), the fibrous web is carried by the textured fabric (12) to a drying cylinder (17). The transfer nip is formed by two rolls of which one is a suction roll within the loop of the textured fabric. The transfer nip has a length which is 5 mm-40 mm. The endless polyurethane belt (11) has a width that exceeds the width of the textured fabric (12). The invention also relates to a corresponding machine.
35 Citations
20 Claims
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1. A method of producing a structured fibrous web of paper, the method comprising the steps of:
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forming a fibrous web and conveying the formed fibrous web on a water receiving felt to a dewatering nip formed by a first press unit and a second press unit and where an endless belt is passed through the nip together with the fibrous web and the water receiving felt, the endless belt having a side which is covered by polyurethane and which contacts the fibrous web in the dewatering nip; after the dewatering nip, conveying the fibrous web by the endless belt to an endless textured fabric which is permeable to air and to which the web is transferred from the endless belt, the textured fabric running at a lower speed than the endless belt; and after the transfer to the textured fabric, conveying the fibrous web by the textured fabric to a drying cylinder, wherein the web is transferred from the endless belt to the textured fabric in a transfer nip, the transfer nip being formed between a first transfer nip roll that lies within the loop of the endless belt and a second transfer nip roll which is a suction roll located within the loop of the textured fabric, the transfer nip having a length in the machine direction which is in the range of 5 mm-40 mm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A machine for producing a structured fibrous web of paper, the machine comprising;
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a forming section that includes a first and a second forming fabric; a dewatering nip defined by a first and a second press unit, through which dewatering nip a water receiving felt is arranged to carry a fibrous web formed in the forming section; an endless belt arranged to run in a loop through the dewatering nip and having at least one side covered with polyurethane such that the polyurethane covered side will face the paper web that passes through the dewatering nip; a textured fabric arranged to pick up the paper web from the endless belt at a point downstream of the dewatering nip; and
a drying cylinder to which the textured fabric is arranged to carry the paper web; anda transfer nip in which the paper web is transferred from the endless belt to the textured fabric, the transfer nip being formed between and by a first transfer nip roll located within the loop of the endless belt and a second transfer nip roll which is a suction roll that is located within the loop of the textured fabric, the transfer nip having a nip length in the machine direction that is in the range of 5 mm-40 mm. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification