Qdos 30 metering pump optimises chemical bleaching process in recycled paper plant

A Qdos 30 chemical metering pump was trialled at a recycled paper facility in Mexico to improve dosing of 50% caustic soda in the chemical bleaching of recycled fibre.

The company manufactures tissue paper to produce napkins, toilet paper, and hand towels at two plants in Mexico. The tissue manufacturer recovers up to 98% of the water used during the manufacturing process.

The Qdos 30 pump replaced the previous pump from another manufacturer that suffered from flow inconsistencies, high wear, and frequent downtime. Over a three-month test period, the Qdos 30 pump delivered more accurate dosing, significantly reduced operating costs, and improved chemical efficiency.

Accuracy and dosing reliability

The Qdos 30 metering pump proved ideal for this application by delivering a stable, controlled dose with a flow deviation of just ±1 mL compared to the setpoint on the control panel.

“The Qdos 30 pump maintained consistent flow throughout the operation, with no significant variations,” said the plant engineer at the tissue manufacturer’s de-inking line.

Thanks to this precision, caustic soda consumption was optimised, staying within plant KPI parameters, while improving the cost-to-production ratio compared to the previous dosing system.

Maintenance savings and increased uptime

One of the most impactful results was a reduction of at least 20% in downtime due to maintenance or pump replacements. The Qdos 30’s tool-free, quick-change pumphead design enabled operators to avoid extended shutdowns due to dosing failures.

The tissue manufacturer replaced the Qdos pumphead once during the three-month trial as a preventive measure, not due to failure. The process involves dosing 50% caustic soda, a highly aggressive chemical, and the site team preferred to stick to a conservative maintenance schedule to avoid any unexpected downtime.

Given those challenging conditions, the Qdos 30 still performed reliably with no unplanned stoppages and the tissue manufacturer’s team really valued being able to do a quick, tool-free pumphead change, which helped reduce downtime by around 20%.

“The ability to change the pumphead at scheduled intervals was a major benefit, helping us reduce labour and unplanned downtime from chemical dosing failures,” said the plant engineer.

Another key benefit observed during the trial was the fluid recovery system built into the Qdos 30. This function proved especially useful in mitigating downtime caused by crystallisation of caustic soda due to ambient conditions, helping to keep suction lines clear and operational.

“The fluid recovery system was a major advantage during chemical crystallisation events, helping us avoid time-consuming line blockages,” added the plant engineer.

Broader adoption of peristaltic pumps

The success of the Qdos 30 trial at the tissue manufacturer reflects a wider shift toward peristaltic pump solutions across the facility.

In addition to the Qdos pump for caustic soda dosing, the plant has also adopted the use of an APEX™ hose pump from Bredel, supplied through a chemical distributor.

The APEX pump is currently used to dose a chemical reducer as part of another stage in the production process. APEX is ideal for handling abrasive slurries and aggressive chemicals.

Following technical consultation and on-site support from Watson-Marlow experts, the Mexico-based tissue manufacturer expressed interest in peristaltic technology for its reliability and ease of maintenance, which has opened up the possibility for broader collaboration.

Key results

• ±1 mL dosing accuracy maintained consistently throughout operation
• Chemical consumption reduction through more efficient use of caustic soda
• 20% less maintenance time and unplanned line stoppages
• Improved KPI compliance and cost-efficiency across the bleaching process
• Tool-free pumphead replacement simplifies maintenance
• Reduced downtime from crystallisation, thanks to the fluid recovery feature

Conclusion

The Qdos 30 pump provided the tissue manufacturer with a robust, precise, and cost-effective solution for one of the most critical stages in recycled paper processing: chemical fibre bleaching. Thanks to its advanced peristaltic technology, the plant was able to reduce chemical and labour costs while improving system availability and dosing reliability.

Following the successful trial, the tissue manufacturer has begun implementing the Qdos 30 in its production area, with plans to gradually replace existing diaphragm pumps as budget allows. Currently, one Qdos 30 is in operation, with future purchases planned based on investment capacity.

Additionally, discussions are underway to expand the use of peristaltic technology into the plant’s water treatment systems, which highlights the tissue manufacturer’s trust in the performance and versatility of pumps from Watson-Marlow.

Learn more about our Qdos chemical metering pump range