Prime time: pump maintenance

A paper mill in Germany has replaced its existing diaphragm pumps with Qdos models from Watson-Marlow Fluid Technology Group to reduce maintenance.

The Schoellershammer paper plant was established 230 years ago and produces fine paper and corrugated board base paper for international markets.

By using Qdos, our stock of spare parts for the metering station has shrunk considerably.

Measurement and control technician, Kevin Dahmen

Like all modern paper mills there is a strong focus on the optimisation of production processes, and particularly on pumping.

“We use over 400 pumps for a wide variety of tasks, including lots of lobe pumps and progressive cavity pumps,” says Holger Malsbenden, maintenance manager at the facility.

“However, we are now increasingly reliant on peristaltic pumps, particularly when it comes to challenging applications and substances that are difficult to transport.”

The peristaltic principle combines efficiency with simple operation, and long intervals between maintenance that help reduce costs.

In contrast to many other types of pump, peristaltic pumps are also dryrunning and self-priming.

These were factors that helped the Schollershammer facility to decide upon the implementation of innovative Qdos metering pumps for dispensing small amounts of anti-foam agent.

“Too much unwanted foam was developing, so we had to add an anti-foam agent to the starch plant,” says Kevin Dahmen, the measurement and control technician responsible for the metering station.

“A total of three pumps transport the additive to the storage tank, as well as directly into the two other tanks.”

Until recently, this job was done by diaphragm metering pumps, but Dahmen says the company was losing patience with what was becoming a growing list of issues.

“Although we were actually happy with the metering performance of the diaphragm pumps, we were concerned about the high amount of repair and maintenance work required,” says Dahmen.

“As the diaphragm pumps were not self-priming, we had to manually add a small amount of anti-foam agent to the pump head after every maintenance operation, which necessitated even more time. However, the biggest problem was that the diaphragm pumps required several valves, which tended to become blocked, leading to yet more maintenance work.”

The Qdos solution

The team discovered that Watson- Marlow’s Qdos metering pump - with its flow range from 0.1 to 500ml/min - was well suited to the application flow rate of 100 to 450 ml/min.

Like all peristaltic pumps, the Qdos is a self-priming and dry-running pump, meaning that there was no need for anti-foam agent to be filled by hand after maintenance.

Immediate process improvements included reliability, increased up-time and ease of maintenance when pumping anti-foam agents used in starching operations, the company said.

Blocked check valves and torn seals are now a thing of the past at Schoellershammer.

In addition, the only wearing component in Qdos pumps is the ReNu pump head from Watson-Marlow, which can be replaced as a complete part, says Dahmen.

“By using the Qdos, our stock of spare parts for the metering station has shrunk considerably,” he says.

“Instead of shelves full of valves, seals and other parts, we now only need one spare part – the pump head. And, in contrast to changing a diaphragm, it takes no more than a few minutes to change.”

The Schoellershammer plant reports that all Qdos pumps have been operating smoothly, with the first pumphead in continuous operation for around one year.