Peristaltic pumps measure up to the needs of demanding customers
04 May 2014
Two quite different manufacturers – one involved in packaging materials, the other in automated laboratory systems – place considerable store by the simplicity and accuracy of peristaltic pumps.
Netherlands-based packaging products specialist, Huhtamaki MoldedFiber Technology BV, is among the first users of the Qdos peristaltic metering pump from Watson-Marlow. 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.
The Franeker mill is a 24/7 operation housing eleven production lines; 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, explains how he has been seeking a solution to one particular problem at the plant:
“We have a 2bar counter-pressure application that involves adding sodium hypochlorite to kill off bacteria in our cooling water flow – it being very important that we disinfect against the formation of algae, yeast and fungi. 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 7bar, 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. Mr Koopmans again:
“We also liked the metering pump idea because of the addition rate. 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 pump head speed is 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 pump head 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 metres of cooling water per hour – so the process is based on flow rate-dependent addition of sodium hypochlorite. Moreover, 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.
“We calibrate the Qdos pump regularly, a task that is performed quickly and easily by shift operators in the mill, and our data indicates no drop in flow rate since installation five months ago,” Mr Koopmans explains. “The pump has been running for two and a half years using the original pump head without any problem. This has given us confidence in metering pump technology and we have just installed our twentieth Qdos 30.”
The Qdos 30 is now being deployed on other applications across the plant, including one that replaces a magnetic membrane pump which adds anti-scale to a heat exchanger. It is critical that this substance is always present in the system to prevent clogging. In another application, Mr Koopmans and his team have replaced a progressive cavity pump with a Qdos30 on a polymer addition application.
Another Watson Marlow customer, the automated laboratory instrument specialist, Caernarfon-based Bee Robotics, is using up to 500 of the company's 400F/M1 OEM peristaltic pumps every year. Applied to a variety of liquid handling applications that complement a wide range of diagnostic kits, the company has been a satisfied customer since its inception in 1999.
A privately-owned enterprise, Bee Robotics today occupies four industrial units in north Wales which house its manufacturing and design facilities. The company has become well established in the automation of molecular and western blot strip based assays, and more recently has expanded into other fields of automation, offering OEM systems to a wide range of clients. The company has ISO 9001 and ISO 14001 accreditations, and operates to ISO 13485 standards.
High on the company’s priority list since day one have been quality and reliability. With 95 percent of its output going to export, Bee Robotics needs to feel confident that its products will perform to a high standard year-in, year-out. Steve Jones, managing director at Bee Robotics, takes up the story:
“It’s a small but competitive market in which we operate hence one of the main differentiators we deploy is our use of modern, well-proven technology. There is no compromise on quality, which is why we have used Watson-Marlow OEM pumps since our origins.”
The 400F/M1 is an extremely compact, single channel, instrument-quality peristaltic pump offering flow rates of up to 200ml/min. The pump shaft is supported by ball bearings which ensure extended gear motor life (the pump is available with four standard gear motors). The pump uses tube elements for simple tube loading, and Luer fittings for easy connection to transfer tubes. According to Mr Jones, The connector design enables the tubing to be replaced in a matter of seconds.
The 400F/M1 pumps are used across four different liquid handling instruments for a variety of medical/biopharm research and production applications, typically handling reagents, wash waters and laboratory samples. On occasions the company will make use of a four-channel variant of the same model.
Among the instruments employing single-channel pumps are the BeeBlot, which offers an open system for strip based assays offering semi-automation for western blot and hybridisation (pumps used for aspiration and reagent addition). The volumes handled range from 50µl to 5ml depending on the application. Mr Jones concludes:
“Our range of applications demonstrates the versatility of these pumps, which is why we are currently taking between 300 and 500 a year. The market is extremely busy at present so I can only see these volumes escalating in the future.”
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