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At the heart of Itaipu: inspection in the penstock
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26/03/2009

Those passing through elevation 144 and viewing the 20 penstocks all in a row, can’t imagine what is passing above or below them. As from the maelstrom of water that runs through the penstocks, only a few drops get left behind. It is the job of Operations and Maintenance to make sure that these drops don't turn into a waterfall. 

 

The ‘dripping’ occurs in the penstocks so called expansion joints, at elevation 111. As it joins two sections of the penstock, this joint can present small leaks. A leak of 200 liters per minute is tolerated; or almost nothing, if compared to the average flow of the penstock - 690,000 liters per second. 

  

If the water coming out of the joint exceeds 200 liters, Operation staff  is put on alert.  With the machine in operation, the technicians make the daily rounds on elevation 111 and, if they find anything out of the ordinary, they put Maintenance into action, who carry out repairs: retightening the screws that connect the joint to the penstock. At the U07 stop, after inspecting the joint, everything was in order. It was not necessary to carry out any maintenance.

 

According to engineer Gabriel Caballero (SMMU.DT), the person responsible for the mechanical area of the turbine, the speed regulator and the water intake, the expansion joint joins two tubes that are submitted to different temperature and pressure conditions. Due to this, each section of the tube behaves in a distinct manner. “If it was a single piece, without the expansion joint to absorb these tension differences, the penstock would become deformed and could burst”, he explained.