Haveri och åtgärdsanalys av MC-pump : Haverianalys av ett återkommande problem för en medium-consistency-pump samt åtgärdsanalys för att upphöra problematiken.

Sammanfattning: This report investigates a recurring problem on a Kamyr MCP 25-15, which is located in the bleaching plant in a paper mill in Värmland. The MC-Pump Kamyr 25-15 has in the last two years crashed and caused downtime in pulp production. Causing large costs in repairs, personnel and in lost pulp production. By analyzing and studying the damage, the root cause of the failure will be identified. The method to conclude failure hypothesis is by studying and documenting the damage, creating an Ishikawa diagram to divide the characteristics of faults into causes and strengthening the hypothesis with the troubleshooting table in the pump data sheet. The cavitation damage was very clear in the rotating parts and where the degasification occurs. Cavitation on rotating parts with high RPM leads to the movement in the pump housing becomes eccentric and creates vibrations in the pump. The parts of the pump wear out faster and leads to breakdown. The hypothesis indicates that the failure was caused due to cavitation, which means that the failure is not a mechanical fault. By discussing the problems with different pump manufacturers, they gave suggestions on what could solve the problem. Both manufacturers who were contacted mentioned that an external vacuum system would solve the problem. The payback period for the investments is calculated using the payback method. The income in the equation is the cost that is saved in the event of an upgrade or replacement of the pump. As the exact cost of the failure is difficult to follow up, a time interval is developed between the best-case scenario and the worst-case scenario. The payback period is required to be less than 2 - 3 years, which means that both investment alternatives are profitable. Depending on how much pulp needs to be purchased, the repayment can be made within the year.