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Making Rigid Paper

by Derek Cowgill of Rigid Paper Ltd

and Clive de Salis of Rowan House Ltd

Rigid Paper Ltd make corrugated cardboard from recycled paper. They are located by the river Ouse and alongside the canal in Selby, North Yorkshire. The site was very close to being flooded several times during last year and in November the floods were so bad in the area that power was cut off from the site for over a week. Diesel generators were brought in to allow essential work to continue. It was all an unwelcome interruption to near continuous papermaking on the site.

Papermaking at Selby began in 1936 when J Rostron & Sons, a family business, installed the original paper machine which was a board machine, producing heavyweight chip board to replace imported Dutch strawboard.

Other machines followed up to the 1960s when a total of five paper machines were operating producing board, kraft wrappings, hard toilet tissue, fourdrinier chip and test liners. All of these products were converted on site into finished products. The paper machines on the site have come to be known as PM1 through to PM5 where "PM" simply stands for "Paper Machine".

The business was sold to Rigid Containers Ltd in 1978, a family owned business with two corrugated box plants and a single faced corrugated plant. The business was restructured to concentrate on the production of corrugating grades of paper on PM3 and PM5, which were then producing about 20,000 tonnes per annum.

One of the earliest investments in 1982/83 were the ABACUS computer systems on PM3 and PM5, both these systems were linked to Devron steam showers and were the first computer control systems in the UK to automatically control cross machine moisture content. PM5 operated until 1989 by which time output from the site had risen to 40,000 tonnes per annum. As a result of changing market demands, PM5 was closed and a new wider PM1 was installed to produce 2-ply Test liners to current market quality demands. Quality and output demands are still being met on PM3 as a result of the most recent update to the ABACUS4 paper machine control system which was completed in 1999.

Total mill output is now 70,000 tonnes per annum with products being supplied to most of the major multinational corrugated box manufacturers.

In August 2000 the Group was acquired by VPK Oudegem, Belgium, a family owned group producing 400,000 tonnes per annum of corrugating grades of paper and box plants in most European countries. Under the guidance of the new owners plans are already in hand to further increase both output and quality at the Selby site over the next few years. This will represent a fourfold increase in production at Selby since 1978.

With production being further increased at Selby one might expect that more time would be allowed for maintenance. This is not what is planned, rather it is intended that the maintenance work can be done in less time by better forward planning and predictive maintenance tools. Careful planning will help optimise production and plant performance.

The proposal was to give the plant engineer the tools to base maintenance predictions on live running plant data that is automatically gathered by the paper machine control system. This will enable better prediction of precise maintenance needs. The maintenance data would need to be seen from workstations within the office network as well as from both the plant control room and the paper scanner data centre. If that was the plan, a small problem became apparent. With the long history of development on site and of high reliability systems it was noted that there is a variety of operating systems on the site: Microsoft Windows 95, 98, NT, Unix and Linux were present on site. Unix and Linux were providing stable and highly reliable operating systems for the paper machine control whereas Windows 95 and 98 were on the network in the offices. Windows NT workstations are both in the offices on the network and also can be found as the operator interface on the less critical control items. How could a maintenance package using live measured data be made available to all the workstations on the network running all these different operating systems?

In 2000 PM3's control system had been upgraded and so the most up-to-date control system on site was the ABACUS4 system. Due to the nature of paper making, stopping and starting a paper machine is not feasible each time sectors of the control software is modified. The ABACUS4 system had been successfully commissioned live and on the run whilst paper making was in progress. In the paper industry the ability to change the control software whilst the plant is running is an important part of paper machine control, this is completely different to process control systems in the Chemical Industry where the process is usually stopped for safety reasons whilst software alterations are made. Thus the software adjustments necessary to the maintenance software could be done on ABACUS4 without interrupting production.

The updated paper machine control system had used standard TCP/IP protocol running on ethernet to link together the distributed control system for PM3. This was fully compatible with the office based ethernet network and so a gateway link was made to connect between the office network and the paper machine control network. This enabled certain workstations in the offices to monitor the paper making and access process performance reports. The interactive viewing system that was included within the control system software allowed key workstations to see the live data displays from the paper machine control system in the offices of key managers. The use of the highly sophisticated interactive viewing system would have been slow and cumbersome on Windows 95 and Windows 98 workstations. Nonetheless, these systems led to the idea of using standard browsers such as Outlook Express and Netscape as the interface for viewing the maintenance data from the office network.

The ABACUS4 control system on PM3 runs on the Linux operating system which is currently running a third of the world's internet sites and fast becoming the dominant software of the world wide web. Thus its capability of interacting with all these different operating systems via browsers was well established. Furthermore the Linux operating system comes with both industry standard PostGresSQL and MySQL database software. The ABACUS4 had an existing maintenance software package running on the PostGresSQL database. Linux is not just highly stable, it is also a true multi-tasking operating system as well as having many of the security features of Unix. The multi-tasking features meant that the data requests for interfacing with the browsers viewing the maintenance data could easily be handled at a lower priority and on different outstations to the more critical process control loops. Thus all the pieces for an acceptable technical solution were all present.

The difficulty in actually doing the work was developing security systems within html software environments. Html only does single transactions rather than logging on to software and automatically logging off when the user finishes. However Linux had the capability of only replying to known ISP numbers and users. Security was achieved by coupling together a secure log-on system with the established ISP and user systems. Thus the interface was developed, the problem was overcome and the new maintenance database interface has now been installed and commissioned. It now only remains to build up the data and set it to work.

Rigid Paper Ltd now has the tools and the capability to move ahead and increase production ... just so long as the river Ouse stays where it is and doesn't burst its banks again.

9th April 2001

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