PRESSURE CHAMBEER RETROFIT FOR USE IN COMBINED THRUST AND

GUIDE BEARINGS WORKING IN HYDRO DYNAMIC LUBRICATION

Brief description of Pressure chamber Retrofit

The Pressure chamber retrofit is primarily designed as an alternate lubrication method of supplying cooled oil to thrust and guide bearing segments of vertical rotors supported by hydro dynamic bearings. It is located with in the oil pot assembly in the annular gap that exists between the outer wall of the oil pot and the thrust collar assembly.  Two non-contact seals are provided on the outer periphery of the pressure chamber, to seal the lubricant from flowing out of the pressure chamber. Inside the pressure chamber, four numbers of radialy converging baffles are placed to direct and channalise the hot oil coming out of the thrust bearing segments. This channalised hot oil comes in contact with heat exchanger copper pipes, laid with in the pressure chamber. These copper tubes cool the oil while it is getting pressurized, during its flow within the pressure chamber. All the oil is directed to flow in to an outer casing, which converges slowly, giving further scope to build pressure. This pressurized and cooled oil enters the required number of vertical pipes placed at the desired locations. These vertical pipes are embedded with dead weight non-return valves. These non-return valves keep the oil from draining back to the pressure chamber. After lifting to convenient height, sufficient enough for gravity flow, it enters the oil collector above the guide bearing segment assembly. The oil collector assembly is so designed it ensures smooth supply of lubricant to guide bearing segments. Excess oil from guide bearing segments is allowed to grain back to the sump. One loop of cooled oil is fed to lubricate the thus bearing segments. The details of the Retrofit Pressure Chamber is  given in the  figure. The Pressure chamber Retrofit was tested in a test rig, and excellant results were obtained. No Turbulence was noticed during the varying speeds, and the pressurised oil was seen lifting in the vertical pipes. When the speed was reduced, the oil levelin the vertical pipe, did not come down, indicating the performance of non-return valves placed at the bottom of vertical pipes. The oil-lift was sufficient enough to fill the guide bearing feed chamber located above the guide bearing segments.