US 5,705,034 AGranted

Method and apparatus for removing water from a web by means of presses

AssigneeVoith Sulzer Papiermaschinen GmbH

InventorChristian Schiel

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Abstract

A wet-press arrangement. The flexible press jacket of a shoe press roll removes the web to be dewatered in a first press nip directly from the wire on which the web has been formed. The web then passes, together with the press jacket, through a second press nip which is developed as a felted, lengthened press nip. The web then passes through a third press nip where it is transferred from the smooth outer surface of the press jacket onto the smooth outer surface of a press roll. The web then travels, together with the latter roll, through a fourth press nip, which again is developed as a felted, lengthened press nip. Following that, the web still follows the press roll up to a place of web removal.

Claims29

Dependent claims

A method of removing water from a fiber web in a wet press section of a paper making machine having first, second, and third press rolls, the first press roll having a smooth outer surface and forming a first press nip between the first press roll and a wire belt, the second press roll forming an extended, felted press nip with the first press roll, and the third press roll having a smooth outer surface and forming a third press with the first press roll, at least one of the press rolls being a shoe press roll having a flexible press jacket with an outer smooth jacket surface, the method comprising the steps of:

carrying the fiber web on the wire belt in a machine direction from a forming section of the paper making machine;
passing the web through the first press nip between the wire belt and the first press roll;
contacting the fiber web directly with the smooth outer surface of the first press roll;
transferring the fiber web from the endless wire belt to the smooth outer surface of the first press roll by passing the web through a first press nip between the wire belt and the first press roll;
carrying the web on the surface of the first press roll through a felted second press nip defined between the first and a second press roll;
continuing carrying the web on the outer surface of the first press roll past the second press nip through a third press nip between the first press roll and a third press roll with a smooth outer surface;
transferring the web thereafter from the first press roll smooth outer surface to the third press roll smooth outer surface;
conducting the web further around the smooth outer surface of the third press roll;
the first press roll is the shoe press roll having the flexible press jacket with the outer smooth jacket surface and the web is conducted past the first press nip including that jacket while the web is in contact with the smooth outer jacket surface of the flexible press jacket;
and
conducting the web thereafter further through the paper making machine.

8 more elements

A wet press arrangement for removing water from a fiber web in a paper making machine, comprising:

a wire belt in a forming section which conducts the web to the press arrangement;
a first press roll having a smooth outer surface and positioned to directly contact the web on the wire belt for removing the web from the wire belt at the contact;
the first press roll having at least first, second and third press nips located around its outer surface, through which the web carried on the outer surface of the first press roll passes in sequence while the web adheres to the smooth outer surface of the first press roll;
the first press nip being defined between the first press roll and the wire belt where the web is removed from the wire belt;
a second press roll positioned to cooperate with the first press roll to define the second press nip;
a press felt which passes through the second press nip in contact with the web;
and means for guiding the press felt to separate from the first press roll and the web after passage of the web and the press felt through the second press nip;
a third press roll positioned to cooperate with the first press roll to define the third press nip;
the third press roll having a smooth outer surface such that when the web passes through the third press nip, the web transfers from the first press roll to the third press roll for being carried on the outer surface of the third press roll;
said first press roll comprises a shoe press roll having a flexible press jacket with an outer smooth surface, a stationary support member about which the press jacket revolves, and a press shoe having a concavely curved slide surface displaceable radially relative to the support member for causing the slide surface to press the press jacket against the outer surface of the opposing one of the press rolls at the respective press nip defined by the press shoe in order to form there an extended press nip;
and one of the press felts passing through the respective press nip defined by the press shoe on the press jacket;
the shoe press roll further including a ledge which is also displaceable radially relative to the support and the press jacket, and the ledge being positioned in opposition to the third press roll with a smooth outer surface such that displacement of the ledge presses the press jacket against the smooth third press roll at the third press nip to form a non-felted press nip.

9 more elements

A wet press arrangement for removing water from a fiber web in a paper making machine, comprising:

a wire belt in a forming section which conducts the web to the press arrangement;
a first press roll having a smooth outer surface, an extended nip, and positioned to directly contact the web on the wire belt for removing the web from the wire belt at the contact;
the first press roll having at least first, second and third press nips located around its outer surface, through which the web carried on the outer surface of the first press roll passes in sequence while the web adheres to the smooth outer surface of the first press roll;
the first press nip being defined between the first press roll and the wire belt where the web is removed from the wire belt;
a second press roll positioned to cooperate with the first press roll to define the second press nip;
a press felt which passes through the second press nip in contact with the web;
and means for guiding the press felt to separate from the first press roll and the web after passage of the web and the press felt through the second press nip;
a third press roll positioned to cooperate with the first press roll to define the third press nip;
the third press roll having a smooth outer surface such that when the web passes through the third press nip, the web transfers from the first press roll to the third press roll for being carried on the outer surface of the third press roll;
at least one of the smooth first and third press rolls comprises a shoe press roll having a flexible press jacket with an outer smooth surface, a stationary support member about which the press jacket revolves, and a press shoe having a concavely curved slide surface displaceable radially relative to the support member for causing the slide surface to press the press jacket against the outer surface of the opposing one of the press rolls at the respective press nip defined by the press shoe in order to form there an extended press nip;
and one of the press felts passing through the respective press nip defined by the press shoe on the press jacket;
the shoe press roll further including a ledge which is also displaceable radially relative to the support and the press jacket, and the ledge being positioned in opposition to another of the press rolls which is a second one of the press rolls with a smooth outer surface such that displacement of the ledge presses the press jacket against the second smooth press roll at the respective press nip to form a non-felted press nip;
a fourth press roll positioned to cooperate with the third press roll for defining a fourth press nip, and a second felt passing through the fourth press nip in contact with the web;
a fifth press roll positioned for contacting the third press roll for defining a fifth press nip which is positioned past the fourth press nip in the path of the web around the third press roll, wherein the third and the fifth press rolls each has a smooth outer surface.

11 more elements

Dependencies are inferred from the claim text.