Dimensionally stabilized roller body
AssigneeSchwabische Huttenwerke GmbH
InventorsHeinz-Michael Zaoralek, Jurgen Kruger
Life of this patent
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Abstract
A roller body for a roller, for pressure-treating and/or temperature-treating a web-shaped medium, for example paper, wherein said roller body is a casting body made of an iron-based alloy comprising graphite lamellae; particular regions of the roller body are placed under tensile stresses during or after production, said stresses being larger than those which occur in these regions during transport or operation of a roller, wherein the additionally applied tensile stresses trigger local plastic deformations in peripheral regions of the graphite lamellae, such that once the tensile stresses are no longer applied, the roller body behaves elastically and no longer permanently deforms, up to the stress level achieved.
Claims37
A roller body for a roller, for pressure-treating and/or temperature-treating a web-shaped medium wherein said roller body is a casting body made of an iron-based alloy comprising graphite lamellae, wherein particular regions of the roller body are placed under tensile stresses during or after production of the roller body, said stresses being larger than those which occur in these regions during transport or operation of a roller, wherein the applied tensile stresses trigger local plastic deformations in the peripheral regions of the graphite lamellae, such that once the tensile stresses are no longer applied, the roller body behaves elastically and no longer permanently deforms, up to the stress level achieved.
The roller body as set forth in the preceding claim, wherein the tensile stresses applied are rotationally symmetrical with respect to a rotational axis of the roller body.
The roller body as set forth in the preceding claim, wherein said bending load applied to the cast roller body is applied successively and symmetrically about the rotational axis of the roller body.
A method for manufacturing a roller body for pressure-treating and/or temperature-treating a web-shaped medium, wherein:
- the roller body is cast from an iron-based alloy containing carbon;
- and
- once solidified, exhibits a material structure comprising graphite lamellae,
- wherein particular regions of the roller body are placed under tensile stresses during or after production, said stresses being larger than those which occur in these regions during transport or operation of the roller and causing the roller body, once the tensile stresses are no longer applied, to behave elastically and to no longer permanently deform, up to the stress level achieved by the tensile stresses.
The method as set forth in the preceding claim, wherein, in order to apply the tensile stresses, the roller body is subjected to a bending load which is at least 1.5 times larger than a bending load caused by the roller body's own weight under gravity.
The method as set forth in the preceding claim, wherein the bending load is at least twice as large as the bending load caused by the roller body's own weight under gravity.
The method as set forth in the preceding claim, wherein the bending load is at least three times as large as the bending load caused by the roller body's own weight under gravity.
The method as set forth in the preceding claim, wherein the applied bending load is distributed symmetrically about a rotational axis of the roller body.
The method as set forth in the preceding claim, wherein the pressure body is rotationally mounted and unrolls on the roller body, partially or completely around a rotational axis of the roller body.
The method as set forth in the preceding claim, wherein the pressure body is pressed constantly against the roller body as it unrolls.
The method as set forth in the preceding claim, wherein the pressure body is pressed with a constant force against the roller body as it unrolls.
The method as set forth in the preceding claim, wherein the roller body is rotationally driven.
The method as set forth in the preceding claim, wherein the pressure body is pressed against the roller body at a number of pressure points arranged in an even distribution about a rotational axis of the roller body, and is disengaged from the roller body between two adjacent pressure points.
The method as set forth in the preceding claim, wherein the pressure body is pressed against the roller body at a number of pressure points arranged in a symmetrical distribution about a rotational axis of the roller body, and is disengaged from the roller body between two adjacent pressure points.
The method as set forth in the preceding claim, wherein the bending force is increased in stages or continuously during straightening.
The method as set forth in the preceding claim, wherein the treatment generates alternating tensile stresses of locally different sizes in the roller body's cross-section.
The method as set forth in the preceding claim, wherein the thermal treatment is performed by means of radiant heaters.
The method as set forth in the preceding claim, wherein said cooling medium is dry ice.
Dependencies are inferred from the claim text.