Nip control method and apparatus
AssigneeConsolidated-Bathurst Limited
InventorsRene Larive, Osman J. Walker
Life of this patent
Estimating the term…
Abstract
This invention provides a method and an apparatus for use in controlling a nip through which material is passed. The apparatus comprises at least one means for generating a magnetic field and means for locating the magnetic field generating means at a selected position along the length of one of the pressing elements, adjacent to the element, to thereby affect only a portion of the length of the element, thus controlling only that portion of the length of the nip which is generally aligned with the affected portion of the pressing element.
Claims16
A method for controlling a desired physical property of a product involving a web material subjected to a roll pressing operation, wherein said property is controlled by said operation, the method comprising the steps of:
- passing said web material through a nip formed by two co-operating pressing elements, where at least one of said elements is a rotating roll and where at least a portion of said roll is made of a material which will allow the local diameter of any transverse segment of said roll to change in dimension and thereby change the nip pressure associated with said segment when energy in the form of a magnetic field is directed at said segment;
- producing and directing said energy to at least one of said transverse segments of said roll so that the nip pressure between said roll segment and the other said co-operating element will change in response to changes in said energy thereby effecting changes in said roll pressing operation;
- taking a measurement of said physical property;
- generating an electrical signal proportional to said property measurement;
- taking said signal and using it to control said changes in said energy so that said physical property will be controlled by said changes in said roll pressing operation.
An apparatus for controlling a desired physical property of a product involving a web material subjected to a roll pressing operation wherein the property is controlled by such an operation comprising means for passing said web material through a nip and means for forming said nip which nip is formed by two co-operating pressing elements where at least one of said elements is a rotating roll and where at least a portion of said roll is made of a material which will allow the local diameter of any transverse segment of said roll to change in dimension and thereby change the nip pressure associated with said segment when energy in the form of a magnetic field is directed at said segment;
- means for producing and directing said energy to at least one of said transverse segments of said roll so that said nip pressure between said roll segment and the other said co-operating element will change in response to changes in said energy thereby effecting changes in said roll pressing operation;
- means for taking a measurement of said desired physical property;
- means for generating an electrical signal proportional to said property measurement;
- means for taking said signal and using it to control said changes in said energy so that said physical property will be controlled by said changes in said roll pressing operation.
Apparatus for treating a web of material comprising two co-operating rotating rolls forming a nip, means for passing the web of material through the nip, a plurality of means for selectively generating a magnetic field, said generating means being divided into two rows adjacent each other and being located along selected positions adjacent the roll, the generating means in one row staggered with respect to the generating means in the other row, means for controlling each magnetic field generating means independently of the other means, such that when the generating means are operated, they control only that portion of the length of the nip generally aligned with the affected portion of the roll.
Apparatus for treating a web of material comprising two co-operating rotating rolls forming a nip, means for passing the web of material through the nip, at least one means for generating a magnetic field, and means for locating the magnetic field generating means at a selected position along the length of one of the rolls and adjacent to the roll to affect only a portion of the length of the roll when the generating means is operated whereby to control only that portion of the length of the nip generally aligned with the affected portion of the roll, the locating means comprising supporting means adjacent the roll and over the length of the roll, mounting means provided for mounting the magnetic field generating means on the support means, said mounting means being slidably mounted on the support means for movement along the length of the roll.
A method for controlling a desired physical property of a product involving a web material subject to a roll-pressing operation wherein said property is controlled by said operation, the method comprising the steps of passing said web material through a nip formed by two co-operating pressing elements where at least one of said elements is a rotating roll and where at least a portion of said roll is made of a material which will allow the local diameter of any transverse segment of said roll to heat up and to change in dimension and thereby change the local nip pressure associated with said segment when energy in the form of a magnetic field is directed to said segment, producing and directing said energy to at least one of said transverse segments of said roll so that the nip pressure between said roll segment and the other said co-operating element will change in response to changes in said energy thereby effecting changes in said roll-pressing operation, taking a measurement of said physical property, taking said measurement and using it to control the said changes in said energy so that the physical property will be controlled by said changes in said roll-pressing operation.
Dependencies are inferred from the claim text.