Whether earthmoving machines, horizontal drilling rigs or forestry machines, GIEBEL Adsorbers® protect the entire hydraulic system of mobile machines and thus ensure reliable operation and long maintenance intervals, even if the tanks are under a preload of 0.3 to 0.8 bar.

Excavators, drilling rigs and forestry machines

Mobile machines are used under harsh environmental conditions and must function reliably over a long period of time. Use in wind and weather is a challenge that these machines have to withstand.

Adsorber necessity

Due to the large temperature fluctuations and humidity in outdoor use, there is a high risk for the hydraulic system. If it heats up and cools down again, condensation will form in the tank and contaminate the hydraulic oil. In addition, biodegradable hydraulic oil, often of the Panolin brand, is used so as not to pollute the environment in case of leakage. However, these synthetic esters are highly hygroscopic and attract atmospheric moisture. The bio-oils decompose by water and age prematurely due to hydrolysis.

If ambient air is sucked into the tank, the moisture will remain in the tank. If the hydraulic tank cools down at the end of work (critical from below 9.2°C), the humidity in the tank will condense. This means that the risk of condensation water damage is is very high for a mobile machine.

Adsorber on an excavator

To permanently protect an excavator from water, aeration dryers are a very effective and simple measure. While dirt particles from a size of 3μm are separated, the effect of complete air drying is added. Depending on the installation situation, two GIEBEL Adsorber® series are recommended.

On the one hand, the robust metal version “Adsorber MA”, should be used when the adsorber can be easily damaged during operation. On the other hand, the simpler plastic version “Adsorber VV” can be used. These adsorbers also hold up under tough environmental conditions, as the housing is made of impact-resistant polycarbonate and polyamide.

Valve adapter for tank preload

To build up and maintain the required overpressure in the tank, the “valve adapter” accessory is used. This component has an outlet valve with 0.3 to 0.8 bar opening pressure, so that the function of the excavator is guaranteed.


The use of an adsorber ensures that water from the air is no longer a problem for the hydraulics of a mobile machine. Even under the toughest conditions and with existing tank overpressure, machine reliability is increased and maintenance costs are reduced.