Its a metal particle detector. It has a "Grid Switch" that oil flows through. There is a positive and a negative side to the switch, with perforations that allow the oil to pass through. When macine bearings become damaged the metal shavings are captured on the switch. Those metal particles make a connection between the possitive and negative and automatically shuts the machine down before further damage occurs. Prior to this invention, the first sign of trouble was machine malfuction or failure form major damage, which would usually result in plant closure. Plant closure meant no productivity and unpaid "vacation" for employees. Thanks for your interest, I was starting to think I was the only one that found this interesting!
