On this recent project, the management team at a desalination plant contacted us after two of their intake pumps failed at a critical time.
The plant had recently been operating at full capacity for a while because of abnormally low rainfall combined with higher than average seasonal temperatures. The result was that reservoir levels were low and their ageing pumps were constantly in operation.
In fact, these pumps were over 25 years old and had reached the end of their useful working life, which was consistently providing a steady flow of desalinated water at over 300M³H above 6 bar.
After speaking to the client, our job was to replace these pumps with alternatives which offered the best combination of suitable pump technology, performance and price.
What did we specify for our client?
For this particular application, we considered all of the parameters and specified two of our proven 12” submersible borehole pumps.
This is a robust design of multistage submersible pumps easily capable of achieving medium capacities and high pressure thanks to the unique diffuser and impeller design. Due to the highly advanced micro casting technology, the whole range is long lasting, highly efficient and easy to maintain.
They will be sent the plant where they will be used for seawater intake as part of the desalination process. The pumps offer superior efficiency operating between 77% and 81% efficiency, with a sand tolerance of 50g/M³.
A wide variety of materials are available for use in seawater. However, we chose these pumps as they’re made completely from duplex stainless steel.What’s more, an important design feature of our borehole pumps is the thrust bearing which supports axial loads, reduces axial movement and wear on the pressure-producing parts. Manufactured in PTFE and filled with 25% carbon/graphite, this is a high-performance engineering plastic that enhances PTFE’s wear resistance, compression strength and stability, making it perfect for seals and bearings in heavy use applications. It’s also a low-friction material which will minimise contact wear with the rotating impeller.
Variable speed operation for greater flexibility
We fitted the seawater intake pumps with 92Kw motors with insulated windings. This would make sure that the pumps are suitable for variable speed operation as pump speed is often altered to match the required capacity.
Moreover, unlike other submersible borehole pumps the external cables are not spliced. With connections only required at the motor entry point and control panel, this reduces the chance of motor cable failure and short circuits taking place.
The motors are rewindable as standard and filled with oil for enhanced cooling, lubrication and durability, or alternatively, with a water/glycol mixture for sensitive locations requiring environmental compliance.
If you have an application requiring the transfer, circulation or distribution of seawater, and need expert, impartial help and advice, speak to North Ridge Pumps today to see how we can help.
