18 centrifugal pumps
choosing a centrifugal pump just got easier
Almost 70% of the standardised pumps in use today operate at a constant motor speed and are usually combined with IE3 asynchronous motors. Pump manufacturer KSB has developed an alternative approach – a smart drive solution which aims to reduce the complexity of variants, while also increasing planning reliability for the engineering contractor. flow found out more.
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n applications which require fixed speed pump sets, the pump is usually adjusted to the design point by machining its impeller. “Our new MyFlow Technology marks a fundamental change to this concept,” explained Daniel Gontermann, Product Management Drives & Mechatronic Solutions at KSB SE & Co. KGaA. “With this new technology, the required head and flow rate can be adjusted via the motor by selecting an individual fixed speed, a capability which offers clear benefits to operators and OEMs.” This new approach makes it possible to optimise pumps to meet specific system conditions after the production process. This does away with the need to trim the impeller during production to match the calculated design point. To make this advance possible, KSB has combined a cost-effective, motor-mounted minimum frequency inverter with its IE5 SuPremE synchronous reluctance motor and the latest generation of its Etanorm pump range. Where the selection process traditionally involved using asynchronous motors alone, the exact adjustment to the required flow rate was achieved by first selecting a suitable pump and then fine-tuning it by reducing the impeller diameter. However, this required a wide range of pumps to choose from. For example, KSB’s Etanorm range alone is made up of 43 sizes, but now, with MyFlow Technology, only 18 sizes are needed to cover the same H-Q selection chart. In practice, fewer variants mean that pumps do not necessarily need to be produced on an order-specific basis, making inventory management much easier. The pumps can also be customised within a few minutes of receiving an order, or even once they are installed in a system. Through extensive characteristic curve analyses and calculations, KSB’s development engineers have been able to prove that this reduction in the number of sizes brings no disadvantages concerning hydraulic efficiency or the pumps’ suction characteristics. Speeds ranging from around 1000 to 4500rpm can be set. This generally means that the same pump power
Quarter 2 2019
output can be achieved with a smaller pump casing. Less material means lower costs for the pump’s hydraulic system and less space for storage. This also makes product data maintenance and inventory management easier for system operators. Another technical advantage of this concept is the working principle of the IE5 SuPremE motors. They feature around four per cent higher efficiencies at www.bpma.org.uk
