Environmental pollution and climate change continue steadily. In response to these dramatic developments, laws have been passed to reduce pollution, such as the Euro standards for exhaust emission. Complying with these pollution limits calls for additional measures, such as installing extra exhaust treatment systems next to the combustion engine. This takes up a lot of space inside the machine, however. In addition, global pressure and the demand for higher energy efficiency rise. This finally results in the hydraulic tanks being given increasingly complex and smaller shapes. These designs significantly limit the amount of air separation that can take place inside the tank, so more free air circulates inside the hydraulic system.