Metering pumps overtake diaphragms for Canada water 11 October 2012

Watson-Marlow Pumps' new Qdos 30 metering pump is supplanting traditional diaphragm pumps for treating potable water in Barrie, Canada.

"Because we have a high concentration of iron and manganese in the Barrie region we use sodium silicate as a sequestering agent in the potable water we supply to customers," explains Ron Baumgart, lead hand for ground water supply within the Water Operations Branch of the City of Barrie.

"Sequestering does not remove [iron and manganese], but instead binds it in soluble form to prevent the compound from oxidising on contact with air or chlorine," he continues.

But while diaphragm pumps have been the models of choice to handle the four-to-six parts sodium silicate typical dosage, maintenance costs meant a suitable alternative has long been on the wish list.

"Sodium silicate tends to give a hard coating to the ball valves in diaphragm pumps," explains Baumgart.

"This leads to clogging, meaning the pumps require disassembly and repair. Sometimes we can spend in the region of $300—500 on spare parts alone annually, without considering labour and travelling time."

Another problem is that the silicate dres when the diaphragm pumps stop, an effect that damages the diaphragm when pumping operations recommence.

So when the local Watson-Marlow distributor, Metcon, approached the Water Operations Branch with its new Qdos metering pump, asking for a trial, Baumgart readily agreed.

"Investing in new technology is easy to justify if it can improve water service and delivery," he says.

So a pre-production Qdos metering pump was installed at one of Barrie's potable water stations last summer, which has been running without incident or maintenance ever since.

"We got the dosage set up and didn't touch it – it just ran," says Baumgart. "In April we got a production version Qdos 30 with the patented ReNu pumphead technology and it's still in place to this day. Again, we haven't needed to impart any maintenance whatsoever."

And he continues: "We are now looking to replace diaphragm pumps when they reach end-of-life or as we upgrade our SCADA control systems. And these pumps are now added to our preferred suppliers list."

Brian Tinham

Related Companies
Watson Marlow Pumps Group

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