Paper No. 82
By Troy Feese
Pumps and Systems, Sept. 1997, pp. 44-45.
A municipality purchased several units to pump water on an emergency basis for fire fighting. These units are located around the downtown area and can provide water through portable pipes and hoses in case a major catastrophe cuts off the primary water supply to fire hydrants. Each unit consists of a V-12 diesel engine driving a five stage vertical centrifugal pump through a right angle gearbox with a 1:1 ratio. The 1600 hp engine has an operating speed range of 1200 to 1800 rpm. The engine flywheel connects to the gearbox through a drive shaft that has universal joints on each end.
This article describes how failures of the water pumping system were linked to torsional vibration. It also shows how a solution was developed using computer analyses. Field tests were performed to verify that the solution was adequate to prevent additional failures.