Description Check your oil? Puradyn Filter Technologies would like to. The company has developed a bypass oil filtration system that can be used in internal combustion engines and pieces of hydraulic equipment that rely on lubricating oil. The Puradyn system works in conjunction with a standard oil filter to remove solids as small as a micron (1/39 millionth of an inch), along with liquid and gaseous contaminants. Puradyn markets its filtration systems worldwide; target customers include OEMs, commercial trucking fleets, and operators of construction machinery. Puradyn has not been profitable, however, and the company's auditors have questioned whether it can stay in business.