Danfoss is building on the success of its novel water-based hydraulic
power transmission systems with several new products, launched last month
at Hanover
Danfoss introduced its 'Nessie' water hydraulics range back in 1995.
Since then, this environmentally friendly, fluid power transmission
method has found its way into many different types of application,
particularly those in which the use of oil raises compatibility problems.
Independent tests, moreover, have established that water hydraulics is
actually considerably more energy efficient than pneumatics. However,
Danfoss is quick to point out that the water based hydraulic system is
not a replacement for those that are oil-based, but simply a 'fourth'
technology among other modes of power transmission, including pneumatics,
oil hydraulics and electric drives.
The hydraulic medium itself and not the technology makes the difference
between oil and water hydraulics. Most obvious is the elimination of
environmental pollution risk. Just one drop of oil could spoil a whole
batch of food production, and require specialised cleaning in the
aftermath of contamination. Water is neither explosive nor inflammable,
so systems such as Nessie are suitable for use in hazardous areas.
The energy saving aspects of water hydraulics were quite spectacularly
demonstrated by a Danish energy research institute (DEFU) and the Danish
Energy Agency who, with Danfoss' help, replaced pneumatically operated
cylinders with water hydraulics on an item of processing plant at an
abattoir. Whereas the pneumatic system's power consumption was
81,900kWh/year, the water hydraulic system power consumption was measured
at 19,700kWh/year - a saving of 76%.
New product
Hitherto, the power packs have been supplied as ready-to-fit units
providing 1-220 litre/min of water at pressure up to 140bar. Launched at
Hanover last month, Mini Power-Pack (see main picture) represents a more
modular approach. These very compact systems are totally leak-proof and
corrosion resistant, and modules start at a very basic level, capable of
actuating one single-acting cylinder. This can be extended to the
actuation of one or more double-acting cylinders.