The amount of visible dirt in pulp, paper, or paperboard can critically affect its usefulness and value. A high number of visible dirt specks, and/or specks that are easily noticed in visual examination, may detract more from the usefulness of the paper material than would a lower number of specks, or specks that are less easily noticed. For a mill trying to control or monitor its papermaking process, the most important parameter might be the absolute physical area of dirt, or the number of dirt specks present in an inspection area; for end users, the overall visual impression may be the critical parameter. In either case, a mill can’t improve its dirt count without an accurate way to measure dirt and specks in its product.
Procemex, an international supplier of machine vision systems for the paper, pulp, and print industries, has designed a system that can detect and analyze dirt and specks online in pulp lines to the full width of the line. The solution is the first real-time dirt count analyzer that offers double-sided detection of dirt and specks in pulp production. The system complies with ISO5350-2 standards, and gives full documentation according to TAPPI/ANSI T563 standards. Sampling offline measurement systems are no longer needed, and the system offers a rapid return on investment by making it possible to reduce the number of quality and compensation claims.
Because it is an online measurement system, the Procemex Dirt Count Analyzer can visualize dirt to the operator in real-time, and it stores the location coordinates of dirt
specks. The solution is designed to detect dirt and shives in pulp using smart cameras and strobe LED illumination online. Tracking is done on every sheet, in full-width, and on both sides of the web. Camera pixel resolution is 0.1 x 0.1 mm, so even the smallest dirt is caught accurately. The system provides information about dirt count per square meter and dirt area per square meter (ppm).
The system has an easy-to-use, illustrative graphical user interface. It documents the amount of dirt per set, per bale, and per time. It can be connected with bale tracking systems and customer quality data management systems. A complete history is always available online since data is stored for later use in the system database.
CASE STUDY: PULP MILL #1
The customer placed an order following an online trial at the mill site and after researching conventional systems on the market.
The Procemex-TWIN System on a pulp dryer includes an online dirt count analysis in the after dryer position. Dirt count analysis is performed after dryer with the help of camera beam and light beam reaching across the machine. Intelligent cameras detect dirt continuously in transmission illumination according the TAPPI or ISO standards, and provide operators with real-time information about changes in the amount of dirt and shives.
At this pulp mill, the system consists of a Procemex Dirt Count Analyzer system with 22 cameras in an IP65 rated beam. The system uses Procemex-Flex high-speed FullHD matrix camera technology together with strobe LED illumination. The mill’s ERP data system has a link to Procemex Dirt Count Analyzer values.
The system displays the amount of dirt per bale, and this gives the customer the opportunity to remove bales with excessive amounts of dirt and to downgrade only those individual bales that do not meet end user requirements. The amount of statistical data gathered is used to analyze the process continuously and change operating parameters accordingly.
Long-term analysis of the dirt data, coupled with control system data, led to discovery of problems relating to slowly recurring process equipment behavior. The mill was able to resolve these issues, thus increasing overall process efficiency and helping to reduce the overall amount of dirt.
CASE STUDY: PULP MILL #2
The challenge: A mill customer had an older system with a “black box” that had a dirt count number output system. Because the system was old, the mill had trouble getting support and spare parts. The old dirt count number system was based on a one-bale measurement. The customer wanted a modern dirt count analyzer that could classify according to the ISO 5250-2 specification.
The solution: Procemex offered a solution based on the brand new ECO-power zoned strobe LED-light and smart camera Procemex Flex with full HD resolution at the pulp dryer; the same type of camera is also used by the mill in the Procemex Web Monitoring System on a paper machine. The Procemex cameras and LED lights easily penetrate the thick pulp web to produce extremely detailed and accurate images.
The Procemex Dirt Count Analyzer measures on three out of seven bales, and the system is designed for the customer to expand to measure all seven bales just by sliding in more cameras and LEDs from the side into the cross
The Dirt Count Analyzer is showing trends per bale, per set, and more. The simple yet effective design makes it easily customizable. The Procemex system is widely accessible from other mill systems via various links or database access. The most critical advantage the customer experienced was the early discovery of defects, which enabled the operators to take timely actions. This resulted in increased production and sales.
The Procemex Dirt Count Analyzer.
The Procemex Dirt Count Analyzer offers double-sided detection of dirt and specks.
Illustration of the dirt count analyzer beam.
The web monitoring beam cameras.