Platform on civil engineering, underground infrastructure, energy, construction equipment & construction machinery
In one of the Netherlands' largest renovation projects
Demako is part of a select group of companies that focuses entirely on the mechanical engineering systems, mechanics, and moving parts of movable bridges and locks. That specialized expertise is fully put to use in the renovation of the Krammer Locks: from drive systems and leveling systems to gates, valves, and roller carriages. All components that determine whether the lock operates safely and reliably fall within the company’s scope. According to Demako’s specialists, this is the “Champions League” of mechanical engineering.
For Demako, the contract came at a special time. The company had been involved in the bidding process through another party, but that situation changed when that party deemed the work too risky and ZEEKR’s mechanical engineering partner withdrew. This prompted the consortium to look for a specialist who could take on the entire mechanical engineering aspect. “That phone call came at exactly the right time,” says Managing Director Thomas Beckx. “We were already familiar with the specifications, the requirements, and the technical parameters. That allowed us to adapt quickly, even though the scope ZEEKR had in mind was slightly different from what we had originally planned for.”
”The renovation of the Krammersluizen has been divided into several subprojects. Within that framework, our work lies at the intersection of mechanics, drive technology, and motion systems,“ says Bert Snauwaert, project manager for the Krammersluizen at Demako. ”We are not a general steel contractor. Our strength lies in the specialized aspects of the work: everything that moves, everything that requires tight tolerances, and everything where mechanical engineering expertise is essential.”
Some of the existing installations will be completely removed. “For example, parts of the push-boat lock will be dismantled and will not be reinstalled after the renovation. Four large wall gates in the yacht locks will also be replaced.” The biggest technical challenge for Demako, however, lies with the moving structures. Among other things, they are responsible for the door actuators in the push-boat locks and the new leveling system that will be integrated into the lock gates.
A key goal of the renovation is to make the water management system more sustainable. “The existing basin system uses large pumps that consume a lot of energy,” Thomas explains. “In the new system, we’ll make much greater use of natural elevation differences and gravity.” Bert adds: “If the water level in the Oosterschelde is low enough and the level in the basins is high enough, the basins will soon be able to drain by gravity. This will eliminate the energy-intensive pumps from the system. To this end, we are supplying and integrating new gates and knife-edge valves, including the corresponding actuators. The installation is part of a completely revamped water management system that makes the operation of the locks more efficient and sustainable.”
Another unique feature is the new approach to separating saltwater and freshwater. “In the 1980s, a conscious decision was made to use a system in which water was pumped to prevent mixing as much as possible. In the updated design, this separation is achieved using, among other things, a bubble screen and a new leveling system in the lock gates,” Bert explains. To this end, large butterfly valves are integrated into the gates themselves. “We have previously applied this principle successfully at the Princess Beatrix Locks, as well as at the Pierre Vandamme Lock in Belgium, and it now once again forms an important part of the renovation of the roller gates.”
In addition to renovating existing structures, Demako is also working on entirely new installations. “A new fish passage with a flushing mechanism is being built between the push-boat locks. We are responsible for the complete design, engineering, and construction of the moving parts and the steelwork,” says Thomas. “For the hydraulic drive system, we’re collaborating with Bosch Rexroth, one of the other partners in the project. We’re also carrying out a thorough overhaul of the existing drive systems for a pumping station and a culvert.”
According to both gentlemen, what makes the project special is the combination of new construction, renovation, and modifications to existing structures. “Everything you tackle brings surprises. Our colleagues from other disciplines are running into this as well. The Krammersluizen complex dates back to the 1980s, and all the systems have been in operation for quite a few years. A good example of this is the lower roller carriages on which the enormous roller doors of the push-lock locks move,” says Bert. “The two lower roller carriages for the spare door are currently in our workshop and have been completely disassembled. They are being overhauled, and various structural steel modifications are being made to them.” The leveling valves are also largely manufactured in-house. Only the motors are purchased. In this way, Demako combines specialized engineering with its own production capacity.
Although things are still relatively quiet on site, construction is already in full swing behind the scenes. “One of the most important milestones is scheduled for October, when the first renovated roller door of the push lock will be reinstalled,” Thomas notes. “At the Iemants shipyard, the final reinforcements are currently being installed and adjustments made so that we can install ‘our’ leveling valves there. In addition, a new hydraulic system from Bosch Rexroth will be installed, and all electronics will be updated. Before commissioning, an extensive Factory Acceptance Test (FAT) will be conducted, during which all systems will be tested together before the gate returns to the Krammersluizen.”
With approximately 43 full-time employees, supplemented by contractors and specialized partners, Demako contributes a relatively small but highly specialized component to the overall project. “Our people live and breathe mechanical engineering. We’re not generalists, but specialists in moving parts, drive systems, and lock mechanics. That’s our field of expertise,” Bert emphasizes. That specialized knowledge is crucial for a renovation of this scale. Dozens of parties are collaborating on the future of the Krammer Locks, with Demako ensuring that all moving parts actually move as intended.
