High efficiency, high reliability cooling water pumps

Paul Boughton

Specially designed for pumping large quantities of critical cooling water within fossil and nuclear power generation applications, the CUP-CVP, concrete volute pump, from ClydeUnion Pumps, an SPX Brand, offers exceptional performance and efficiency, whilst providing extremely high plant availability.

Power used in the generation of electricity reduces the overall power plant efficiency. Reducing the power consumed for major applications such as cooling water pumps therefore offers significant sustained increases in plant efficiency and profitability.  Availability of the cooling water pump is also critical to plant running times and production capacity.

The CUP-CVP pump is designed to provide higher flow rates than conventional vertical bowl pump designs, thus reducing the number of pumps required. The CUP-CVP design operates at higher efficiencies and experiences minimal wear during operation due to its low running speed, resulting in exceptionally high reliability and availability approaching 100 per cent.

The pump has been shown to exhibit no noticeable deterioration in efficiency over 100,000 hours of operation in power generation applications, with a minimum service life of 10 to 12 years between internal maintenance inspections. Compared with metallic pumps, this long-term efficiency saves kilowatts and provides prolonged, maintained power plant performance.

Furthermore, the specific SPX design of the volute ensures the concrete is in compression which improves sealing. This design also enables a single concrete pour to produce the casing, which minimises any air entrainment and further reduces the risk of leakages. The single pour also makes installation easier and more economical.

As the pump casing is predominantly produced in concrete this eliminates potential corrosion problems often experienced with suspended bowl pumps (especially in hot sea water). The lower specific speed of concrete volute pumps results in a slower running speed and shorter submerged setting depth which significantly reduce the depth of civil dig and overall land area excavation required for the intake and pump house structures.

The CUP-CVP can be provided for flow rates up to 120,000 m3/hr and delivery heads up to 50m. It is engineered for hydraulic efficiency and its non-corrosive ‘cast-in’ casing is manufactured to suit the onsite civil construction programme.

Once installed, the design incorporates a packed gland with a pneumatically operated inflatable seal (to prevent flooding when the packing is replaced) and a removable inner cartridge for ease of maintenance. Journal bearings are oil bath lubricated and tilting pad thrust bearings are used to improve reliability and increase bearing life. An efficient, balanced impeller reduces thrust loads and increases stability.

The large flow rate of a single concrete volute pump will achieve a duty equivalent to several vertical bowl type pumps, reducing the number of pumps required on site, and with typically two points higher efficiency than alternate technologies, it offers long term power savings.

SPX and ClydeUnion Pumps have proven experience in providing these exceptionally reliable and efficient pumps which are ideal for pumping large volumes of cooling water. The special shape of the volute and single concrete pour ensure maximum robustness to protect metallic innards from damage and further makes these units easier to install than equivalent multi-pour designs. The pump design and low speed operation also ensures very low wear, minimum maintenance and high reliability in order to maximise power generation over long periods. The high reliability of the CUP-CVP also eliminates the need for a standby unit.

Overall, the CUP-CVP offers long term power savings through higher, maintained efficiency over many years of service and is supported by the impressive global engineering and service provided by SPX.

For more information, visit www.spx.com

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