INVESTIGATION OF FATIGUE FAILURES OF TREES FEED PUMPS OF THE CTE BOILERS “CARLOS MANUEL DE CESPEDES”

Abstract

After 25 years of service in the month of December 2004, there was a fracture of the shaft of one of the pumps boiler feed, which was utilized for said pump and significantly affected the generation capacity of the Central. The fracture occurred after a prolonged period of use, but after this first fracture geometrical modifications are made and material changes that have caused the fractures have occurred repeatedly and more frequent. In this paper we develop a framework of analysis and a general procedure of bending moment diagram in the tree hyperstatic centrifugal pumps feed the boilers and showed that in normal operation is not possible the occurrence of faults. This paper assesses the impact of the possible misalignment of the oil pump and the pressure plate of the pump failures. The torque of the oil pump is so small that the possible misalignment of the same do not create a significant hazard to the tree. Misalignments pusher plate if they have a substantial impact on the fatigue life of the shaft. Just the same misalignment between the 1st and 0.5 or for increasing the bearing reaction in the bearings that are in the area of the tree is increased markedly and produce a bending moment at the section of failure which leads to failure by fatigue.