Hydrotary | Hydraulic rotary union

Video explaining the Hydrotary function

Keeps hydraulic systems dry, even in the event of leaks!

In agricultural machines, numerous functions are performed hydraulically. High-performance seals make these technologies extremely reliable.

So it’s frequently troublesome when hydraulic oil needs to be fed to any sort of rotary actuators. Agricultural machines commonly contain variators, for example, for adjusting speed (threshing drum, reel, blower for cleaning the grain, cooling fans).

These actuators always need an rotary union, which feeds the oil through the rotating component (variator disc or fan hub) to a linear cylinder. The seals of these rotary union require a minimal amount of leakage for their own lubrication, which describes the “sweating” of these components. As the number of operating hours increases and especially when the hydraulic oil is dirty, the sweating becomes a leak. A couple of drops of oil are not the actual problem and according to a DIN standard, this must even be expected by the customer.

However, if these drops end up in the wrong place and, for instance, come into contact with the variator belt, or are blown by the cooling fan onto the engine and turbocharger, or enter the radiator core when the fan is switched over, the consequential costs are tremendous and outages at the wrong time are inevitable. Such potential fire risks are also a thorn in the side for the insurance industry.

The goal of the Hydrotary innovation is to drain away all oil leaked from these actuators in a controlled manner, either back to the oil reservoir or, even better, to a small transparent leakage monitoring container. In this way, the condition of the seals can be observed at any time via the amount of leakage in a corresponding period. Replacement of the seals can thus also be scheduled and postponed to off-peak times. Because a dual seal system is always necessary for this technical solution, this alone increases the service life accordingly.

The most important benefit, however, is that costs due to consequential damage and outages can be avoided!