I was changing the PCV (positive crankcase ventilation) valve on my car which reminded me of an application for the EXAIR Line Vacs that is becoming popular with manufacturers and users of large stationary engines that I will share with you this week.
On piston combustion engines, some of the combustibles leak past the piston rings and enter the crankcase. This is referred to as blow-by. It contaminates the oil and builds up pressure in the crankcase that has to be vented somewhere.
Auto companies install a check valve (PCV) and rout the blow-by back into the intake manifold to be reburned. For stationary engines, especially those in the natural gas industry, this is not a prefered method. Oil is lost and it is not a clean burn.
The method they employ is pictured below. They install an oil filter then use an EXAIR Line Vac to pull the crankcase vapors through. The oil is reclaimed and returned to the crankcase and the air is sent to the engine exhaust.
This method has increased the life of the oil, reduced oil consumption, and provided a cleaner burning engine.