Bratislava, 26 June 2015
In May 2015, Cofely successfully implemented the EUROVEA petrol station cleaning project for the third year. The technologically demanding service was carried out under full operation directly on the Danube riverbank.
The beginning of cooperation
The cooperation between Cofely and Eurovea in the field of supply and installation of technologies started in 2009 with the servicing of air handling units. “In 2013, during one of the meetings, Eurovey representatives raised the issue of maintenance of pumping stations and pumps. Our Technical Service Department team responded to this suggestion and, free of charge, developed a project including a technological procedure for pump dismantling and installation and subsequent servicing. The client liked our proposal and after signing the contract we immediately started the preparatory work,” says Peter Mizner, head of the HVAC service group. Pumping stations
The pumping station, located in one parallel line with the left bank of the Danube, consists of three hydraulically connected wells, 12 metres apart, and serves to pump cool water from the Danube, which then cools the condenser (chiller) systems in Eurovey. Before cleaning each of the wells, it is necessary to remove the pump, which is then taken to the service centre. There it is disassembled, a comprehensive service is carried out and the necessary spare parts are replaced. The cleaning of the wells is carried out in stages, with only one pump being shut down at any one time during the servicing, due to the need to ensure the continuous operation of the pumping station. The work shall be carried out according to a predetermined and agreed schedule.
“An important part of our work is the coordination meeting, which usually takes place before the work starts. This is where the responsibilities of the different groups and people are defined and the work areas are set out. The crane layout is then determined and the individual tasks that need to be carried out as part of the service work are set out. Thanks to this coordination, everyone later knows what their competences and tasks are and where they are to move within the project,” explains Peter Mizner. Cleaning the rechen with the help of divers
In addition to the pumping station, there is also a so-called rechen near the wells – a technological unit that cleans and filters the water of larger particles and coarse dirt. The water from the rechen is then piped to the individual wells 1 – 3 via process pipes. In addition to monitoring and cleaning the rechen itself, Cofely also monitors the clogging (fouling) of the intake grates and the condition of the bedrock.
“The rechen cleaning is carried out by experienced technicians and divers who dive to a depth of 3 to 4 metres, where there is almost zero visibility. In addition, during the work, it is necessary to constantly monitor the weather side effects – the state of the river level, the speed of the flow, the temperature of the water,” says Peter Mizner. Telescopic crane on the Danube embankment
The technological procedure for the service work of the pumping stations involves removing and inserting the pumps, which are located on the Danube embankment in individual wells at a depth of 13 metres below the surface of the ground. The pumps, which are lifted out of the wells by a one hundred tonne telescopic crane, are then transported to the service centre. During transport, they are secured against damage (e.g. breakage) by custom-made auxiliary elements (prisms, brackets). After the cleaning is completed, the embankment terrain is revitalised to its original state.
“The biggest challenge of the whole project for us was the dismantling and installation of the pumps. We knew from previous experience of other contractors that this would not be easy and could end up damaging the pump. Just placing the one hundred tonne crane on the cobblestones of the Danube embankment required precise calculations with regard to the statics and the load on the road structure and the subsoil. We worked with the radius of rotation of the boom and the load of the crane in the design, taking into account the weight of the pump,” says Peter Mizner. “In addition, the actual cleaning of the rechen and pumps under full operation was also interesting. For this we used additional 4-stroke motor pumps that were built on a pontoon into the open river. These pumped water directly into the wells during the cleaning of one station,” adds Peter Mizner. Hydrogeological tasks
The work also includes hydrogeological tasks, which are based on the existing knowledge of the technical design of pumping stations and hydrogeological conditions in the area. Before and after cleaning, the actual condition of the wells is documented by video monitoring. Other work carried out includes casing cleaning, perforation of wells and removal of sediment from the bottom of the well by airlift. Turnkey Project Delivery
Cofely delivered the entire pumping station cleaning project to the client on a turnkey basis. From the preparation of the technological project, through the implementation, including the provision of equipment (crane, auxiliary pumps) and specialists (divers carrying out industrial underwater cleaning), to the preparation and delivery of the final report with proposed service measures.
“After receiving and reviewing the final report, the client was positive about the quality and professionalism of the work delivered. Based on their satisfaction with the design and execution of the first pump station cleaning project in 2013, we were able to win this contract for future years. Cleaning of the pumping stations is important for Eurovea not only in terms of ensuring the smooth running of the equipment, but also in terms of increasing the efficiency of the operation and reducing the energy consumption of the pumps,” concludes Peter Mizner.
