At the end of this module, you will be able to:
- Describe safety hazards and safe work practices associated with a dry end QCS scanner
- Explain how QCS scanners operate
- Identify and describe the type of sensors used to measure moisture, weight, and caliper
- Explain how moisture, weight, and caliper profile issues are handled by the control system
- List the benefits of improved profiles
The following key questions are answered in this module:
What variables are typically measured by dry end QCS scanners?
Commonly measured variables include moisture, basis weight, and caliper. Both machine direction and cross-machine direction results are reported.
Can I work safely around a dry end QCS scanner that contains a radioactive measuring device?
Even though they are shielded and emit only very low levels of radiation, avoid working on or near the scanner heads for an extended period of time in order to minimize your exposure risk. Only qualified technicians should clean or work on the sensors and scanner heads.
Where are caliper adjustments made on the machine?
Caliper profile adjustments can be made at a calender stack, either by changing a roll deflection or using a zone profiling system.
Are any of the profiled variables related to each other?
Typically, there are interactions between the profiled variables. For example, if there is a high weight zone, that zone will mostly likely experience high moisture. There may also be a caliper issue in that zone.
What are the benefits of flatter sheet profiles?
A dry end QCS scanner system can yield benefits in costs, sheet quality, and machine productivity. Improved runnability is related to all of these, and is perhaps its biggest benefit.
Below is a transcript of the video sample provided for this module:
The QCS Scanner is a device located just before the reel that provides continuous measurement of key dry sheet properties. The scanner consists of two heads and a support frame. Sensors are installed on the heads, which are mounted on opposite sides of the sheet directly across from each other. The two heads move back and forth across the sheet together and send their results to the QCS computer. The data that is measured and recorded is compared against set points and used to make required adjustments to the process.
Use the additional resources and links below to learn more about this topic: