Holding millions of litres of water at bay
When it was decided that new doors needed fitt ing on
the four locks a t Trollhättan on the Trollhättan
Canal in central Sweden, the
Swedish Maritime Administration turned to Sjuntorp Industrisupport AB for
dewatering help. The requirement, to pump 37 million litres of water out of the
locks and keep them dry throughout the entire process, was handled by 26
Grindex pumps. After 25 days the project was considered a success and the locks
were reopened.
Essential renovation of an important piece of history
When the Trollhättan Canal was opened in 1800, it made the waterways of
western Sweden, between the
North Sea and Lake
Vänern, accessible by
sailing ship. Since then the 82 kilometer long stretch of the River Göta, which
rises 44 m in total, has gone through a number of major upgrades. The six
locks, for example, all have double floors and electrically and mechanically
operated doors and gates. Inspections by the
Swedish Maritime Administration however, revealed that the gates at the four Trollhätten locks
could become a potential hazard. Therefore, on August 25th 2011, the
canal was closed at Trollhättan for essential repairs, including renovation of
the locks, changing/upgrading
of the lock pumps and installation of the new doors.
Around the clock pumping
Each lock,
which can house ships up to 4000 metric tonnes, 89 m in length, 13 m wide and 5.4 m deep, typically
holds approximately 9500 m3 of water, the equivalent of 9 seconds of
water flow in the River Göta. With four locks to empty, powerful and reliable
pumps that could operate around the clock were required. The Swedish
Maritime Administration, which is responsible for the locks, contacted Sjuntorps Industri Support, as they have
successfully handled the dewatering process in the past. With over 300
contractors on site and tight deadlines to meet, it was imperative that every
stage of the operation went according to schedule. This of course meant
ensuring the locks were kept dry at all times.
Big pumps for a big job
Armed with
information from past projects at Trollhättan, staff from
Grindex’s technical department assisted Sjuntorps Industrisupport AB with the
sizing of the pumps. With 37 million litres of water to be drained before work could get started, 3 slurry, 22 drainage and 1 sludge pump (including stand-by pumps) were recommended, the
largest of which can handle 12 m3 water/min.
Work began emptying the locks on Friday night, and by Sunday at around
midday the job was completed and work could begin on the renovations. “The
drainage pumps were used for the first stage and the sludge and slurry pumps
were used to remove the water under the upper floor of the locks,” says Grindex
sales engineer, Rolf
Mejbert. “This water is quite different to the majority of the water as it’s
much denser. Mud, sediment and even quite a lot of fish can be found down
there. Fortunately we were able to pump the fish out without harming them,” he
concludes.
Trusted partner
The Grindex pumps remained on site throughout the project removing
rainwater and water leaking through the canal doors. According to
Håkan Ohrling, of Sjuntorps industrisupport AB, “This
is the third time that we have assisted The Swedish
Maritime Administration with this operation. On a project of this scale, with
so much at stake and so many contractors relying on you, everybody needs to
know that your pumps can handle the task at hand, keeping the locks dry around
the clock. Therefore we had a service agreement to ensure that the pumps were
operational throughout the process.”
After 25 days the project was
deemed a success and the canal was re-opened to shipping. As for the Grindex
pumps, they were given a standard service and put back into storage awaiting
the next rental project.