Sealed and pressure balanced oil lubricating system

Abstract

A sealed and pressure balanced lubricating system for high pressure rotary equipment includes a housing with a bore divided by a slidable piston into a lubricant chamber and a gas chamber. The gas chamber communicates with an area of the equipment which is exposed to high gas pressure and the lubricant chamber communicates with bearings within the equipment. During operation gas pressure forces the piston against the lubricant to pressure feed the bearings. A relief valve in the piston is opened, after the equipment stops and the pressure therein returns to atmospheric, in the event that pressurized gas has become entrained in the lubricant due to leakage past shaft seals. Such gas forces the piston back towards the gas chamber; the relief valve contacts an actuator and is opened; and the gas escapes to atmosphere through the piston and the gas chamber. The invention prevents problems due to high pressure gas entrained in lubricants of high pressure rotary equipment by quickly exhausting such entrained gases when the system pressure returns to atmospheric.