If you can measure it accurately and reliably you can control it!

MultiPerm NT.01 ^TimeSlice

Scanning Porosity Measurement System

Key Benefits

General description

Value Systems has announced an intelligent scanning system that makes on-line measurement of porosity in the cross direction (CD) on a slice-by-slice basis. The company claims a world first in slice-by-slice CD porosity measurement on-line.

This development of the MultiPerm technology is significant oil machines where final porosity is the most, or one of the most, important measurement variables of the finished sheet. Products such as cigarette tissue, filter paper and filtration media normally have very tight MD and CD specification limits, for porosity. Sometimes these specifications are tighter than those for weight and moisture content of the sheet.

Additionally, final porosity is often subject to rigorous customer defined testing procedure, during the conversion process, where relatively small sampling batches dictate whether the converted product continues on to realise the value-added financial objectives or it whole batches are rejected and this contribution is totally lost. This is an expensive way to make mistakes on these high value-added processes. It is one of the reasons Value Systems has developed the MultiPerm NT.01 ^TimeSlice scanning system to provide complete and continuous analysis of porosity, throughout the production process, combined with a comprehensive report for each reel made. With the MultiPerm system providing accurate statistical analysis, on a continuous basis, operating personnel can take the necessary steps to reduce rejects and prevent out-of-specification product being forwarded into the conversion process in the first place, or on to the customer. The result is a reduction in manufacturing costs. a decrease in rejects and fewer customer complaints or returns.

By design, contemporary on-line porosity measurement systems use single sided sheet sensor technology. Air between the sheet and contacting sensor is always present and, for a number of reasons, usually variable. Generally, this air is known as ‘leakage’. Knowledge of how the sheet is contacting the surface of the sensor is essential for maintaining measurement accuracy and to ensure that any variance in leakage between the surface of the shect and the face of the sensor is properly compensated for. MultiPerm achieves this through its own individual sheet contact sensor technology. Variances in leakage can occur with changing sheet tension or draw, sheet flap, creasing, cockling, piping, rippling, vibration, etc.

The MultiPerm NT.01 ^TimeSlice system provides a slice-by-slice database set-up to allow the operator to select how many individual readings to take at each slice position, before the sensor moves on to the next slice. The system will automatically ignore bad readings, due to, for example, sheet flap at reel turn-up, and then make a good measurement before moving to the next slice position.

A CD profile of slice-by-slice porosity is displayed together with porosity trend and distribution for each reel. Intelligent signal processing provides clamps, limit checks and exponential filtering of the measurement at every slice across the machine. The MultiPerm system scans the measurement cycle to achieve a sampling frequency every 2.5 cm of the paper web in the machine direction, for example 200 Hertz at 300 m/min, 400 Hertz at 600 m/min and 800 Hertz at 1200 m/min. Even on less sophisticated machines the MultiPerm can allow adjustment of CD target profiles to optimise final CD porosity. Most mills close the loop immediately after system commissioning; controlling refiners, stock flows, fillers, binding agents, etc.

All current MultiPerm NT.01 installations are vertically up-gradeable to the MultiPerm NT.01 ^TimeSlice full web scanning system. Value Systems offers a Performance Guarantee that provides a 2-sigma correlation of ± 3 % with the Quality Control Laboratory.

MultiPerm uses a PC based platform and the Microsoft NT operating system. The operator interface has been developed by Value System based on the industry leading graphical application language from National Instruments – LabVIEW.

The MultiPerm NT.01^TimeSlice system provides on-line porosity measurement for most continuous sheet or web processes. Systems are installed on cigarette tissue, sack Kraft, industrial filtration, automotive filter and food filter grades, tea bag, coffee filter, printing and copier grades, latex based, non-woven, saturating grades, and glass fibre products. Repeat orders account for over 60 % of MultiPerm sales. Every installation has resulted in an increase in average porosity, a decrease in porosity spread and reduced rejects. Immediate benefits of the freer sheet are improved run ability and a reduction in draw between sections, leading to fewer sheet breaks. Porosity related losses at grade changes are generally eliminated.

Text by Jon Marshall, founder and general Manager of Value Systems..

Pricing and Delivery

Please contact us for more details on pricing and delivery.

Copyright © 1999-2006 Value Systems
Last modified: December 09, 2006