Suspended Solids Controller Used in a Paper Mill

Measuring solids in the paper and pulp industry has traditionally been challenging due to the variability in solids loads, colors, and particle size distribution. The SoliSense® suspended solids controller from Pi offers a dependable, maintenance-free solution to this issue.

In 2018, Northwood Tissue, a leading manufacturer of high-quality paper hygiene products, purchased a CRONOS® SoliSense® unit.

 Paper mills, which require large amounts of water for the paper-making process, aim to recycle as much water as possible, a practice known as “closing the loop.” After pulping, the mill produces “thick stock,” a mixture of water and suspended solids like cellulose fibers and fillers, which are essential for paper production. This thick stock is then diluted into “thin stock” (containing about 1% suspended solids), which is transported onto the “wire” – a mesh that collects solids to form the paper. Excess water drains through the mesh and is collected in a large tank, referred to as “white water” due to its appearance. Monitoring the suspended solids in the white water is an integral part of the water treatment process.

The SoliSense® from Pi can measure suspended solids ranging from 2 NTU to over 8%. It is stable, reliable, and suitable for all types of water, including potable, waste, and process waters. The device requires calibration and maintenance only once every 12 months, maximizing operational uptime and reducing costs. It is also equipped with an “AutoClean” function, which automatically flushes the optical window with a clean water jet at preset intervals to prevent sensor fouling.

The SoliSense® can be installed in various configurations, such as dip mounting into a tank or channel, at-line measurement with flow cells, or in-line measurements via pipe insertion, as seen in this case. The pipe insertion option uses a valve, allowing the sensor to be retracted and removed without shutting down the process. This feature proved beneficial when Pi’s service engineers visited Northwood Tissue’s site for maintenance and calibration, as it ensured the process continued without interruption, saving both time and money.

To learn more about the technology that drives the SoliSense®, please click here. To discuss your application with one of our experts, give us a ring on 01282 422835.