Method and apparatus for roll profile measurement

Apparatus for producing a reading indicative of non-uniformities in the cross-machine nip pressure profile of two cooperating rolls, comprising, in combination:

• first and second rolls with a nip line of contact therebetween;
• a continuous piezoelectric strip arrayed in a continuous uniform spiral about the surface of the first roll for 360.degree., said piezoelectric strip being capable of producing a first signal corresponding to the nip force applied by the mating roll against the piezoelectric strip;
• signal conditioning means for receiving the first signal and producing a read-out signal indicative of the nip force at predetermined locations across the surface of the roll as determined by the piezoelectric strip passing through the nip;
• display monitoring means for receiving the read-out signal and providing a display of the read-out signals at lateral points across the surface of the roll indicative of the nip pressure profile along the nip line.

Apparatus for producing a reading indicative of non-uniformities in the cross-machine nip pressure profile of two cooperating rolls, comprising, in combination:

• first and second rolls with a nip line of contact therebetween;
• a plurality of individual piezoelectric crystals arrayed uniformly in a spiral in the cross-machine direction on the surface of the first roll, said piezoelectric crystals each being capable of producing a first signal corresponding to the nip force applied by the mating roll;
• signal conditioning means for receiving the first signal and producing a read-out signal indicative of the nip force at predetermined locations across the surface of the roll as determined by the piezoelectric crystals passing through the nip;
• a multiplexer for receiving the signals from the individual piezoelectric crystals, said multiplexer being electrically linked with the signal conditioning means to pass successive signals from piezoelectric crystals passing through the nip to the signal conditioning means;
• display monitoring means for receiving the read-out signal and providing a display of the read-out signals at lateral points across the surface of the roll indicative of the nip pressure profile along the nip line.

Apparatus for producing a reading indicative of non-uniformities in the cross-machine nip pressure profile of two cooperating rolls, comprising, in combination:

• first and second rolls with a nip line of contact therebetween;
• pressure sensitive means arrayed in the cross-machine direction on the surface of the first roll and extending spirally around the roll surface along a face width thereof for 360.degree., said pressure sensitive means being capable of producing a first signal corresponding to the nip force applied by the mating roll against the pressure sensitive means;
• signal conditioning means for receiving the first signal and producing a read-out signal indicative of the nip force at predetermined locations across the surface of the roll as determined by the pressure sensitive means passing through the tip;
• encoder means for providing a second signal indicating the angular position of the nip force on the pressure sensitive means relative to a fixed reference on the first roll, said second signal being produced at predetermined time intervals;
• said signal conditioning means receiving the second signal and correlating it with the first signal to produce the read-out signal;
• display monitoring means for receiving the read-out signal and providing a display of the read-out signals at lateral points across the surface of the roll indicative of the nip pressure profile along the nip line.

Apparatus for producing a reading indicative of non-uniformities in the cross-machine nip pressure profile of two cooperating rolls for processing a traveling web comprising, in combination:

• first and second rolls for engaging the traveling web along a nip line of contact therebetween;
• pressure sensitive means spirally arrayed on the surface of the first roll along a face width thereof, said pressure sensitive means being capable of producing a first signal corresponding to the nip force applied in the contact between the web and the pressure sensitive means;
• encoder means for providing a second signal indicating the angular position of the nip force on the pressure sensitive means relative to a fixed reference on the first roll, said second signal being produced at predetermined time intervals;
• signal conditioning means for receiving the first signal and correlating it with a second signal and producing a read-out signal indicative of the nip force across the surface of the web;
• display monitoring means for receiving the read-out signal and providing a display of the read-out signals at lateral points across the surface of the web indicative of the web profile along the nip line.

A method for producing a reading indicative of non-uniformities in the cross-machine profile of a traveling web of material comprising, in combination:

• nipping the traveling web between first and second rolls along a nip line of contact therebetween;
• providing pressure sensitive means spirally arranged on the surface of the first roll along a face width thereof to produce a first signal indicative of the force of the nip on the web against the pressure sensitive means as the pressure sensitive means passes through the nip;
• determined the angular location of the position of the pressure sensitive means in the nip relative to a fixed reference on the first roll;
• correlating the first signal with the angular position and producing a read-out signal indicative of the nip force against the pressure sensitive means and its lateral location in the cross-machine direction across the web;
• displaying a predetermined number of readings of the read-out signal indicative of the web profile in the cross-machine direction.