The Qdos 30 metering pump from
Watson-Marlow Pumps Group is
proving a success in Barrie, Canada,
a city with a track record for the
quality of its potable water supply.

Sodium silicate is used as a
sequestering agent in the water. It
used to be pumped by diaphragm
pumps, but high maintenance costs
meant an alternative was needed.

Ron Baumgart, lead hand for
ground water supply within the
Water Operations Branch of the
Corporation of the City of Barrie,
says sodium silicate tends to give a
hard coating to the ball valves in
diaphragm pumps, leading to
clogging and expensive repairs. Also,
he says silicate will dry up when the
pumps stop, which can damage the
diaphragm when pumping restarts.

A pre-production Qdos metering
pump from Watson-Marlow was
installed in one of Barrie’s potable
water stations in June 2011. This ran
without maintenance until April ’12.

In April a production version Qdos
30 with ReNu pumphead technology
was installed. With no seals or valves
in the flow path to clog, leak or corrode
it has boosted flow performance
from 0.1 to 500 ml/min at 7 bar.