Methodology for diagnosing hydraulic oil in production machines with the additional use of microfiltration

The aim of this article is to present the methodology of testing hydraulic oil in accordance with the requirements of ISO, SAE, and NAS standards. The article also presents the results of oil testing using a portable oil condition analyzer. The condition of the oil is understood as the amount of impurities in the oil and the amount of water. In the process of using industrial machines with hydraulic installations, the properties of the oil change from the moment of pouring new oil into the system during operation. In most cases, this is caused by changes in the ambient temperature and the heating of the hydraulic oil during operation. Additionally, a method for reducing the cleanliness class of hydraulic oil through microfiltration on portable stations without the need to replace the oil with new one is presented. The hydraulic oil tests conducted by the authors also take into account the assessment of the oil condition determined before and after microfiltration. A single oil microfiltration lasting from 6 to 8 h, depending on the condition of the oil, allows the oil cleanliness class to be lowered by one class.