Packaging specialist swaps membrane pumps for Qdos metering pumps

Netherlands-based packaging solutions provider, Huhtamaki Molded Fiber Technology BV, is among the first users of the Qdos peristaltic metering pump from Watson-Marlow Pumps Group. Qdos 30 models have replaced magnetic membrane pumps and progressive cavity pumps on two applications at the company’s Franeker plant on Holland’s northernmost coastline. For Huhtamaki, Qdos delivers a number of benefits including improved handling of corrosive fluids in a counter-pressure application, constant flow to eliminate pulsing, low addition rate capability and ease of calibration. As a result, the company’s engineering team is now considering standardising on Qdos models moving forward.

The Huhtamaki Group, with origins in Finland, is today a €2 billion, 14,000-strong organisation with 61 manufacturing units worldwide, largely producing consumer and specialty packaging. The company has had a presence in the Netherlands since 1938 and one of the core businesses at its 200+ employee Franeker plant is three-dimensional moulded fibre packaging for food products such as eggs, stone fruit, apples, pears and tomatoes to name only a few.

In the right mould

The Franeker mill is a 24/7 operation housing 11 production lines and pump technology plays a vital role in the production of its moulded fibre board. Although an established customer of Watson-Marlow, the site’s Process Manager, Benno Koopmans, has longed for a solution to one particular problem.

“We have a 2 bar counter-pressure application that involves adding sodium hypochlorite [NaClO] to kill off bacteria in our cooling water flow – it is very important that we disinfect against the formation of algae, yeast and fungi,” he explains. “Until recently we were using magnetic membrane pumps for this task, however, due to the corrosive nature of sodium hypochlorite, leaks into the electrical circuit were commonplace, along with associated downtime and repairs. Like most in our industry we work to tight margins and there are significant costs associated with process downtime.” 

The solution arrived in the form of Watson-Marlow’s new Qdos 30 metering pump, which was installed at Franeker in February 2012. Qdos 30 pumps boost process efficiency by providing accurate, linear and repeatable flow performance from 0.1 to 500 ml/min at 7 bar, even when metering difficult fluids. There are no seals or valves in the flow path to clog, leak or corrode, which means caustic, abrasive, viscous, shear-sensitive, and gaseous fluids can be safely and securely handled.

Precise solution

“We also liked the metering pump idea because of the addition rate, which offers low variation and high significancy,” says Mr Koopmans. “For instance, in dye stock applications where we add colour to egg packaging we need a low addition rate of 0.15-0.2%, but if the revs of the pumphead are too low it can jam and result in colour variation. If this happens it’s what we call a ‘show-stopper’, so any pump we use here must be reliable.” 

Accuracy is so vital at Huhtamaki that Mr Koopmans says flow rate needs to be in the midst of the curve to prevent the pumphead running at very low speeds, which can lead to undesirable ‘pulsing’.

The Franeker plant is using flow meter control on its Qdos 30 pump, which measures the amount of cubic meters of cooling water per hour – so the process is based on flow rate-dependent addition of sodium hypochlorite. Incidentally, Huhtamaki was able to use the existing 4-20mA communications cable used by the previously-installed membrane pump, making the entire system plug and play.

Easy to calibrate

“We calibrate the Qdos pump regularly, a task that is performed quickly and easily by shift operators in the mill, and our data indicates we have witnessed no drop in flow rate since installation five months ago.  The pump has been running for 2.5 years using the original pumphead without any problem,” explains Mr Koopmans. “This has given us confidence with metering pump technology and we have just installed our 20^th Qdos 30.”

Many applications

The Qdos 30 is now being deployed on other applications across the plant. For example, a Qdos 30 has been chosen to replace a magnetic membrane pump which adds anti-scale to a heat exchanger. It is critical that this substance is ever-present in the system to prevent clogging. In addition, Mr Koopmans and his team have replaced a progressive cavity pump with a Qdos 30 on a polymer addition application.

“We are now having discussions to see if we might want to standardise on Qdos technology moving forward. With eleven production lines comprising up to five pumps each, there is significant scope for further installations.”