Pumps manufacturer APE Pumps has been awarded a €4.1-million rectifying contract to complete upgrades at the town of Walkers Ferry’s raw water and high-lift pumping stations near Blantyre, Malawi.

The raw water pumping station, which is located on the Shire river about 40 km north-west of Blantyre, transfers water from the river through the water treatment plant using three pipelines to the lifting station, which pumps it 26 km to Chileka, where a further pumping station boosts the water flow all the way to storage tanks in Blantyre.

The company already manages the R100-million Chileka contract, which it won in April, last year.

Work on this part of Blantyre’s water supply comprises the manufacture, installation and commissioning of eight multistage pumps with electric motors, all motor controls and associated valves, and civil work that includes demolishing and rebuilding all concrete plinths and bases in the pump house.

To complete the work at Walkers Ferry, the company will use contract components already delivered to site by the defaulting contractor, combining it with key equipment to be manufactured by APE Pumps itself.

The company will repair or replace nonfunctional valves and associated actuators, fittings, couplings and pipes, together with all pump sets and related electrical equipment, instrumentation, suction and delivery pipe work and fittings.

In addition, new high-voltage devices, including the power feeder, transformer, main distribution boards and all cable connections and control cabinets, will be installed and are likely to be manufactured in India by parent company pumps manufacturer WPIL, the company says.

It adds that work has already begun.

“When the project is com- pleted, around the middle of this year, all aspects of the existing water intake works and high-lift pumping station at Walkers Ferry will have been rehab- ilitated, renewed or commissioned, ensuring a continued supply of water to Chileka,” says APE Pumps MD Peter Robinson.

Robinson said he was satisfied that work for which the company had tendered two years ago had now been awarded to it.
“We took second place during the Walkers Ferry tender evaluation in 2011, as we were off the mark on pricing,” explained Robinson.

However, he notes that although the previous contractor managed to supply the bulk of the components needed for the contract, the company was asked to leave the site, owing to a lack of progress on the project.

Other Projects
Meanwhile, the company recently refurbished several concrete volute cooling water recirculation pumps for a Southern African power station and will refurbish several more.

The cooling-water pumps at the power station are very large, single-stage vertical machines that were manufactured by APE Pumps in 1983, the company says, and have run to specification for 30 years, with each one transferring water at a rate of just under 6 t/s.
Responding to the request by the power station for a higher flow rate, the company commissioned research by WPIL into the feasibility of modifying the impeller design.
 

WPIL proposed a redesigned impeller that would increase the output of each pump by about 7%, from an output of 5.8 m3/s to 6.2 m3/s, but which would also fit into the existing concrete volute housings, which are fixed and cannot be changed, the company says.

When the refurbishment programme is complete, the combined additional output of all 12 pumps will be 4.8 m3/s, equivalent to an additional pump at the current, reduced rate of flow of the units already installed, which are suffering diminished efficiencies, owing to age, the company says.

The net effect will allow for higher operational turbine efficiencies and additional elec- tricity output from the power station, the company says.

In addition to refurbishing the original pumps, APE manu- factured one new machine to be used as a changeover unit to allow the power station to continue operating while the original pumps were being removed one at a time for refurbishment in Wadeville, Gauteng.