New elastomeric drive couplings for 267 MW diesel power station in Honduras
Picture Diesel Power station Pavana lll Honduras
VULKAN Couplings is replacing the couplings in 16 Wärtsilä engines with the highly flexible RATO S 582Y
THE CHALLENGE The centrepiece of Pavana lll includes sixteen 18-cylinder Wärtsilä V46 engines with a total electrical power of 267.4 MW.
The engines have been installed in two separate halls for the sake of safety, but can be monitored from a single control room that is equipped with the latest monitoring equipment and technology provided by Wärtsilä. All sixteen engines, which have been installed in a flexible manner, use steel spring couplings for torque transmission between the engine and the generator, and these steel spring couplings now need to be replaced following instances of damage.
The disadvantage of the steel spring couplings: They can only be dismantled after a laborious disassembly process and can only be sent to the manufacturer for repair. Thus, it would not only have resulted in considerable costs, but also a long period of downtime and hence unreasonable interruptions in power supply to the Amarateca substation in the suburbs of Tegucigalpa - the country's capital which is home to 870,000 residents.
Picture highly flexible coupling RATO S in Pavana lll
The highly flexible RATO S coupling is a torsionally flexible natural rubber coupling that compensates radial, axial and angular shaft displacements of the connected machinery. The torque is transmitted by elements loaded in shear. Different torsional stiffnesses and damping factors are available to provide satisfactory tuning of the torsional vibration behaviour of the drive system. The essential parts of the RATO S coupling are flexible elements, the membrane and the connecting parts. The torsionally flexible elements can be arranged in one row or more rows dependent on the coupling size and the stiffness level.
THE BENEFITS The great benefit of the RATO S: It consists of four separate segments. Thanks to the segmented couplings, the elements enjoy good ventilation and cooling. In this manner, it is ensured that the coupling can withstand high thermal load and, as a result, have a long service life. The decisive advantage of the segmented coupling design that contributed primarily in the reconstruction at Pavana lies in its extraordinarily high level of user-friendliness when it comes to installation. The elements can be assembled and installed without shifting or displacing the connected machinery. This saves on the time taken in replacing the couplings at Pavana III and reduces the downtimes to a minimum of just one day.
"It was important to us that we follow a reconstruction concept, which reduces the shut-down times as far as possible" explained Nelson Ramirez, the project leader at Lufussa, the operating company. "In VULKAN Couplings we have found a partner where such customer benefits are of great concern and importance. We have been able to fall back on a solution here that has already been proven at our second power station in Pavana."
The highly flexible RATO S couplings are torsionally flexible elastomer couplings that compensate for the radial, axial and angular displacements of the machines connected. The couplings are available in a torque range of TKN = 12.50 to 800.00 kNm.
For more information about the RATO S click here.