Reducing maintenance costs and cutting energy bills has always been high on the agenda for most manufacturers. Where pumps are operating 24/7, this cost-saving ‘focus’ is especially important and, when investigated and acted upon, can result in significant savings, says pump specialist Michael Smith Engineers
In 2006, leading European polyester resins manufacturer DSM Composite Resins of Ellesmere Port made the decision to replace some of its ageing magnetically coupled pumps which were operating on Jarytherm hot oil service, operating at 250degC. These hot oil pumps were running 24/7 as part of a system providing an instant source of heat for the chemical reactors used for the resin production.
Nikkiso high-temperature HX Series canned motor pumps, supplied by Michael Smith Engineers, were identified as the most suitable pumps to replace the existing magnetically coupled pumps. The actual pump selected was an HX25D-G5 with a 30kW motor: it produced an immediate efficiency improvement over the original 45kW magnetically coupled pumps. On the same duty service, the Nikkiso drew 23kW, compared to the original pump’s 45kW, a saving of 40 per cent on energy operating costs.
Commenting on the pump’s performance, Graham Wilkes, Industrial Engineer for DSM Composite Resins said: “The pump paid for itself within 12 months due to the energy savings and reduced maintenance costs. We are very pleased with the results.”
Two smaller HX24C-C5 Nikkiso pumps with 18.5kW motors were installed at DSM Resins in July 2008 and once again produced instant efficiency benefits. These pumps drew 5.88 and 11.33kW, compared with the original magnetically coupled pumps which drew 17 and 18kW respectively.
However, says MSE, the benefits are not just lower running costs: Nikkiso HX pumps also ensure savings on installation. This is because most magnet drive pumps operating on applications where temperatures are 250degC require cooling water to prevent the magnet area from overheating and the magnet strength weakening. Nikkiso’s HX Series has a ceramic stator which requires no external cooling. This results in significant savings on installation as there is no need for additional pipe work required to bring a water supply for cooling and an operating cost saving as there is no need for cooling water.
Eliminating misalignment problems
Other features and benefits of Nikkiso HX canned motor pumps include a one-piece rotor/pump shaft, so any misalignment problems, and the subsequent maintenance issues associated with conventional pumps, are eliminated. Also, Nikkiso pumps have only two journal bearings and a patented automatic thrust balancing system which ensures that both the axial and radial bearing loads are kept to a minimum. This results in longer bearing life and therefore reduced maintenance costs.
MSE can supply Nikkiso canned motor pumps which are suitable for handling capacities up to 1000cu.m/hr and maximum discharge heads up to 210m. High speed and multi-stage options for differential heads up to 420m can also be supplied. These compact, energy-efficient, leak-free pumps will handle corrosive, aggressive or expensive liquids which must not come into contact with the atmosphere.
