The development of the first strip thickness gauge worldwide, that could measure the thickness of the strip during the rolling process in cold mills with an accuracy of m, was the start of our company in 1963.
Vollmer America
January 2006 Newsletter
With Strip Vibration Damper
VUD ST 30 for Wavy Strip
The new VUD DG25 is a thickness gauge for sheet and strip material of 1,5 to 11 mm (appr. .06″ to .45″) thickness. It measures the passing strip by two measurement wheels continuously during the processing. The measurement depth from the strip edge is up to
300mm (11.8″). In this application – limited by the vibration damper – the maximum strip width is 2000mm (appr. 78,5″). The maximum strip speed is 30m/min.
This gauge is designed to measure especially thick and wavy strip. The measurement wheels, each carried by a measurement arm, are large in diameter, in order for the gauge to measure over welds, i.e. the strip can be measured continuously without traversing the gauge off the strip to exempt seams.
The strip passes through a gap between two spring suspended measurement arms. The two wheels measure the strip at an equal measurement load from above and from below. The measurement arm’s spring load is adapted to the individual requirements during the
installation of the gauge so that the measurement rollers follow very wavy strip in the vertical motion.
Due to strip thickness changes, the measurement arms are pushed apart or pulled closer together. The distance between the arms is monitored by a digital transducer inside the gauge. The signals of this transducer are transferred into the Vollmer measurement computer where they are evaluated. In the application shown here, the results are displayed on a PC monitor, visualized by the Vollmer-Software VRecoS.
In case that the passline is not exactly level, the lateral incline of the VUD gauge can be adapted to the slope of the passline, so that the connecting line between the axles of the two rollers is always perpendicular to the strip. In applications with a vibration damping device, this feature is not required.
The strip is led through two sets of guide rollers of the vibration damper, so that even very wavy strip is passing through the gauge without causing too much vertical movements. In the photo, the upper rollers are lifted for strip insertion. During processing, the upper rollers are hydraulically pushed down, so that the gap between the
rollers is about the double size of the strip thickness. Drive side and operator side are mechanically synchronized.
The damping rollers are automatically moved up/down by the commands “Gauge on/off strip”. The upper limit is formed by limit stop switches, the lower limit stop is set mechanically by spacer blocks, their size depending on individual requirements. The damping device is fastened to the site floor by strong screw anchors. The height should exactly match the passline, so that the lower rollers are just driven by the strip but don’t lift it.
With Axially Drilled Sensor Tubes:
New VPMR/bfi Shapemeter Roll
The enhanced design of the new Vollmer shapemeter roll VPMR/bfi has axially drilled tubes for the sensor units. The previous design had the bores for the sensors drilled radially into the solid steel body. The sensors were inserted from the outside, resulting in a nearly seamless surface. Now the tubes for the sensor units are drilled parallel to the roll axis and the sensors are positioned and clamped there with a defined load.
Afterwards the roll surface is ground even and then the roll is calibrated. This combines the benefits of the piezo-electric sensors (wide measurement range but high sensitivity) with a completely closed roller surface.
For the customer, this results in an extremely stable calibration, producing increased operational reliability of the shapemeter roll. The completely closed surface guarantees that even under the worst environmental conditions there will be no marks on the strip.
Stroke plus .8” / minus .9”:
Long Stroke Transducer Type /02
These transducers have a measurement stroke of +2,1 /- 2,3 mm (+0.8″ and -0.9″) and most of their parts are the same as in the standard type MUBE/MOBE-0 transducers with a stroke of +/- 1mm. In order to achieve a good measurement accuracy despite the extended stroke, the modified transducers come with an individual linearization file. This file is copied to the VMF 1000 or VMF 2000 amplifier before transducer symmetry is adjusted.
Any VMF 1000 amplifiers from software version 2.01 and VMF 2000 amplifiers from version 3.29 are ready for this procedure. An upgrade kit for older measurement amplifiers can be supplied.
The modified transducers (i.e. type /02) are recognizable by the groove around the brass cap nut as shown on the photo right. The /02 transducers and their extension cables have 6-pin Tuchel-connectors. The linearization curve is matched to the length of the entire cable connection. In comparison, transducers of the type /0 and their extension cables have 5-pin Tuchel connectors.
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The well-proven BFI version shape measurement roll has undergone a design change that improves its ability to measure the tensions profile on flat product without marking the strip. The detectors have been redesigned to fit into the roll while leaving the surface of the roll completely clear of machined marks. This eliminates the former problems associated with the axially installed sensors.