THE CHOICE OF FLUIDS
A fundamental and characteristic of a hydraulic system is certainly represented by the choice of hydraulic fluid.
An industry more and more advanced and technological which requires efficiency, pressure and temperature of the hydraulic fluid involves a choice with specific characteristics such as high thermal stability, anti-wear characteristics, low chemical corrosiveness and a constant viscosity regardless of temperature.
Having said that you can not locate a fluid that is perfectly in possession of all these features. That is why the operator can select a type of fluid which possesses at least one of these properties and that it is the best compromise for the reference plant.
This choice is made by the operator taking into account different parameters such as the operating temperatures, the type of pump, the valves and the operating pressure.
FACTORS AFFECTING THE PERFORMANCE OF FLUIDS
May vary depending on the process requirements. Usually the max.raccomandata temperature is 150 ° F although systems can also be operated at 250 ° F but this may lead to a rapid decomposition of the fluid and of the additives even in a few days.
Fluids can oxidize with the passage of time, forming decomposition types. Some of these such as the acids may attack the parts of the system such soft materials. Moreover, even a high-temperature prolonged use promotes the formation of decomposition products.
COMPATIBILITY OF THE SEALS
To select the fluid you must take into account the compatibility of this with the seal materials making sure that does not compromise functionality.
It 'should prevent the formation of foam eliminating air leaks in the system. Usually they are formed two types of foam, the surface that is gathered on the surface in a tank and the one caused by entrapped air.
E 'it determined by the maximum and minimum operating temperatures. When the operating temperature is at the maximum, the viscosity of which must be maintained by the fluid is the minimum level, in contrast to minimal temperatures the fluid must not be so viscous as to slide with difficulty.