Compact X-Ray Strip Thickness Gauge
New, Extra Narrow Design
For many years, Vollmer has been extending their product range of excellent contact gauges with X-Ray gauges (Gamma X) and isotope gauges (Gamma A) for strip thickness measurement. Our long experience in making special mechanical adaptations of our gauges to fit exactly to our clients individual applications has helped to develop a wide range on non-contact gauges. This is why the head of our narrowest X-ray gauge is only 120mm (4,73″) wide – far below the size of other makes. This allows the integration of a movable C-frame even in such mills where Vollmerís business competitors can to offer only fixed installations at the strip center.
Even the standard Vollmer non-contact gauge heads are only 160 and 180mm (6.3/7.1″) wide, smaller than other versions on the market. Here we describe an especially compact C-frame which has been very well accepted by rolling mill designers. The interface cabinet and the high voltage generator are integrated into the gauge, so only the cooler unit requires separate mounting. The C-frame is sturdy, small and compact, thus fulfilling the three most important criteria of cold rolling mill designers.
The C-shaped measurement frame, through which the strip passes, carries the X-ray tube in its lower arm and the detector in the upper arm. The strip acts as an absorber, reducing the radiation. The intensity of the transmitted radiation (the portion that passes through the strip) increases or decreases depending on strip thickness variations. The large gap in
the measurement throat is an effective insurance against gauge damage as a result of strip breaks.
The motor driven C-frame is infinitely positioned along the slide base, so the gauge can measure at any location across the strip that the operator selects. As an option, the C-frame is moved continuously across the strip to measure the thickness profile.
The liquid cooled X-ray tube is powered by a high voltage generator. A tungsten shutter blocks the radiation and is opened only during measurement. The shutter allows the interruption of the measurement without having to shut off the X-ray bulb. This means that the measurement can be re-started instantaneously without a loss of time for to the warm-up cycle of the tube. The x-ray beam window over the shutter is blown clean by
a steady jet of compressed air.
Every C-frame has an attached control panel for service. During measurements, the gauge is usually controlled by commands from the automatic mill control over industrial networks such as Profibus or TCP/IP, etc. The operator can control the gauge from his desk with software commands or by hardware switches. The Vollmer measurement computer evaluates and displays the measurement data. The screen display shows the actual strip thickness as well as the deviation from the nominal thickness. Indicators on the screen display whether the strip material is in tolerance.
The radiation source as well as the electronic module can be easily replaced by the customer on site and
then sent to the Vollmer company for repair. The new detector requires only a simple procedure to align with the radiation source by means of a small laser pointer.
With contact, isotope and X-ray gauges, Vollmer is the only manufacturer in the world designing in all these technologies for strip thickness measurement. In international comparison, our company has a longer and more comprehensive history than any other
designer or producer of thickness measurement technology.
We not only design and produce thickness gauges, but a great part of our work is the consulting of mill operating companies and mill designers about the most suitable kind of thickness measurement technology for their particular application. Our engineers in the different specialties have a wealth of background as to which kind of gauge or combination of gauges will be the best choice for their exact application.
Cross Profile Gauge with Sample Height Adjustment:
VBP Enhancement
The new design of the VBP which was introduced a year ago, has been enhanced and now features a height adjustable sample fixture.
The new sample fixture relieves the operator from the need to cut the samples exactly to a certain height. Now he has only to make sure that the edges of the sample are parallel. The sample is put between the clamping brackets in a position where both ends will be clamped. Then the height of the sample support is adjusted by a hand wheel so that the upper edge of the sample meets the height of a plastic gauge which is put on top of the brackets.
In the next step, the brackets are pneumatically closed and the measurement is performed automatically as in the previous version of the VBP. Due to the exact height adjustment, now there are almost no more emergency stops actuated by the protection sensors. These sensors monitor the position of the upper edge when the gauge is measuring the sample, and they generate a signal when they touch the edge.
Roll Form Measurement from End to End:
New VRR Straddle Gauge
The Vollmer straddle gauge VRR measures the form of rolls. It consists of a base frame that is magnetically mounted on the roll and a V-shaped straddle frame which can be traversed along the roll length on a rail of the base frame.
The rail on the base frame is longer than the roll form. This allows the operator to push the straddle frame far enough to measure the entire camber from side to side.
One of the measurement arms carries an adjustable feeler and the other carries a dial gauge. They are mounted on slide pieces which allows adjustment of the straddle gauge to very large range of roll diameters.
For adjustment, the slide pieces on both arms are positioned to the same position on the rulers. This puts the feelers exactly to the level of the rollís center axis so that the roll form is measured at the exact diameter of the roll.
Special Gauge Version for Corrosive Environments:
Chemically Nickel-Plated
Many parts of our gauges are milled from solid aluminum blocks or plates and then assembled to very sturdy gauge housings. Aluminum is easier to mill than steel, is of much less weight and in most environments it is much more resistant to corrosion
than normal steel. Some environmental conditions however (e.g. when a gauge is operated in an atmosphere which contains hydrochloric gas or when it gets in contact with chlorinated liquid) cause considerable corrosion on the gauge body. For such applications most of our gauges can now be made of nickel plated parts. The nickel plating is visible by the color which is more yellow than the natural aluminum surface.
Many Advanteages for Our Customers:
New Shapemeter in Great Demand
The axially drilled BFI-Shapemeter roll has proven to be a amazingly successful development. Not only does it replace the deflector roll in a mill, but it can as well be ground as is a deflector roll.
The bore holes for the pressure sensors are drilled into the roll from its face sides parallel to the axis of rotation. The smallest wall thickness of those holes is 11mm (0.43″). Compared to the previous version (one radial bore hole for each sensor, covered with
a lid), the axially drilled holes hold enormous advantages. The completely closed surface is a basis for operational reliability while the measurement accuracy remains at the proven high level of the radially drilled shapemeter roll.
Compared to the competitive models on the market, the BFI-Shapemeter roll is now technically nearly unbeatable. Its telemetric data transfer, virtually maintenance free design, the option to repair the roll or to replace sensors on site, are most attractive
advantages for the long-term use of this shapemeter roll.
The flexible construction as well has proven to be a decisive advantage when discussing the technical details with our customers. For mill upgrades, we can offer our roll at the same diameter of the existing deflector roll, at a diameter down to 200mm (7,9″). The competitive models often have only specific diameters to offer, which in many cases would cause expensive redesign of the rolling mill table.
For wedge shaped strip, a shapemeter roll cannot be used instead of the deflector roll but only in a special arrangement with the roll lowered from above. Although an expensive construction, but with many competitive advantages as well. Shapemeter rolls of other types cannot be used at all on wedge shaped strip, since the mentioned dipping construction is a BFI-patent, thus only available to users of BFI shapemeter rolls.
