US 10,954,632 B2Granted

Method and apparatus for producing a fibre web

AssigneeTeknologian tutkimuskeskus VTT Oy

InventorsRiku Pihko, Jani Lehmonen, Kay Rökman

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Abstract

According to an example aspect of the present invention, there is provided an apparatus and a method comprising a forming section for feeding an aqueous furnish of fibres on a moving surface to form a shape of a product and a pressing and heating section for removing water from the shaped product received from the moving surface. The pressing and heating section comprises a felt and metal belt that are set to run against each other for receiving the furnish from the moving surface and heating elements for heating the web in at least two pulses including at least one first pulse wherein the product is pressed for at least 10-200 ms on a first pressure and at least one second heating and smoothing pulse wherein the product is heated at least for 10-200 ms on a pressure that is higher than the first pressure, and at least one of the surfaces pressing the product being the smooth metal belt.

Claims19

Dependent claims

An apparatus for forming a fiber web comprising:

a forming section for feeding an aqueous fiber furnish on a moving surface to form a fiber web;
and
a pressing and heating section for removing water from the formed web received from the moving surface;
wherein the pressing and heating section comprises a felt and a smooth metal belt that are set to run against each other for receiving the formed web from the moving surface,
heating elements for heating the web in at least two pulses including at least one first pulse wherein the web is heated and pressed for at least 10-200 ms on a first pressure and at least one second heating and smoothing pulse wherein the web is heated at least for 10-200 ms on a pressure that is higher than the first pressure, wherein at least one of the surfaces pressing the web is the smooth metal belt,
a forming apparatus having a narrowing nip formed of two moving permeable fabrics and a feeding apparatus comprising at least one guide surface that forms a gap together with at least one of the moving permeable fabrics, and at least one feeding opening for feeding furnish to the narrowing nip, and
a first feeding slot for feeding the furnish on the nip of the moving permeable fabrics as one central first flow to form a central layer of the web, second feeding slots for feeding the furnish as two secondary flows perpendicular to the moving permeable fabrics on both sides of the central flow to form second layers of the web, and third feeding slots for feeding two tertiary flows having speed lower than the moving permeable fabrics and being fed on both sides of the central flow, the feeding points of the second slots being upstream of the first slot and feeding points of the third slots being upstream to the second slots.

4 more elements

A method for producing fiber webs, comprising

a forming step for feeding an aqueous furnish of fibers on a moving surface to form a shape of a web;
and
a pressing and heating step for removing water from the shaped web received from the moving surface;
wherein
at the pressing and heating step the shaped web is received between a felt and smooth metal belt that are set to run against each other;
and
the web is heated by heating elements between the felt and the smooth metal belt in at least two pulses including at least one heating pulse wherein the web is pressed for at least 10-200 ms on a first pressure and at least one heating and smoothing pulse wherein the web is heated at least for 10-200 ms on a pressure that is higher than the first pressure, and at least one of the surfaces pressing the web being the smooth metal belt, wherein
a narrowing nip is formed of two moving permeable fabrics and furnish of at least water and fibers is fed into the nip of the fabrics by a feeding apparatus comprising at least one guide surface that forms a gap together with at least one of the fabrics, and
the furnish is fed on the nip of the fabrics as one central first flow to form a central layer of the web-like web, as two secondary flows perpendicular to the moving permeable fabrics on both sides of the central flow to form second layers or the web and as two tertiary flows having speed lower than the fabrics and being fed on both sides of the central flow, the feeding points of the second flows being upstream of the first flow and feeding points of the third flows being upstream to the second flows.

6 more elements

Dependencies are inferred from the claim text.