The viscosity, or resistance to flow, of every hydraulic fluid depends on its operating temperature. The operable range of temperatures in which a fluid is effective is called its "temperature operating window". Position and the width of the window depend largely on the characteristics of the pump and the hydraulic fluid itself.
The operating temperature requirements are defined by the application. Within these limits, from start up to emergency situations, the fluid has to protect the hydraulic equipment. Obviously it is completely different regarding an excavator used outside in summer and winter, or e.g. an injection molding machine, used under pseudo-stationary conditions.
The Hydraulic System Defines the Viscosity Window
The viscosity limits are defined by the hydraulic system itself. At lowest temperatures the hydraulic fluid must still flow, and in maximum temperature situations lubrication must be guaranteed. The ISO grade of the fluid has to be chosen according to the specific operating conditions.
The ISO 46 fluid matches exactly with the limits of the temperature operating window.
An ISO 46 fluid formulated with DYNAVIS® exceeds the requirements of the temperature operating window. It flows easier at low temperatures. That means it has a better mechanical efficiency and it has a better volumetric efficiency at high temperatures.
The ISO 32 fluid formulated with DYNAVIS® fulfills the same requirements on the extremes of the requested temperature window as the monograde fluid one ISO grade higher. So even at maximum temperatures, lubrication is still guaranteed.
This improves the mechanical efficiency enormously.
If it is more important to improve the volumetric efficiency, you can even use an ISO 68 fluid formulated with DYNAVIS®.
DYNAVIS® gives much more flexibility to optimize viscosity within the temperature operating window. Thus, DYNAVIS® saves energy and improves productivity for every piece of hydraulic equipment.