In the past decade, it appears the world is becoming exponentially more extreme, especially environmentally. Regardless of climate, work still needs to get done, and mobile hydraulic machinery exists to get that work done, no matter how extreme.
Although straight off the factory floor not every piece of mobile machinery is manufactured to operate in desert and arctic climes, they can be optioned to work very well in either.
Let’s consider cold weather. The first step is choosing the appropriate fluid. Standard, single-grade hydraulic oil wouldn’t work in zero-degree weather, because it would waste huge energy just to convey itself around the circuit. Even a typical, high-quality synthetic fluid with an excellent viscosity index just won’t do in a severe cold. No, you need arctic grade oil. Arctic oil starts with a low viscosity synthetic base, typically 15-20 cSt, which itself is good for very cold temperatures. However, the oil also warms itself up simply by operating, creating heat from the pressure drop of moving the fluid and the internal leakage of pumps, motors and valves.
Thanks to this characteristic, hydraulic machinery trumps nearly every other mechanical form of power transmission when it comes to working in extreme environments. Moreover, to combat a loss of lubrication related to low viscosity, arctic oils are also heavily modified with viscosity index improvers, preventing the hydraulic oil from getting too thin under operating conditions.
With hot temperature, limiting the contribution to viscosity breakdown through heat is the primary goal; choosing an efficient circuit and efficient components is fundamental, because any fluid lost at pressure is converted to pure heat, which itself can be much higher than ambient temperatures. In this case, load sensing is an important tool, because it provides only enough pressure and flow demanded by the load at each actuator. Although some energy is still wasted, it’s negligible, and more or less just what’s required to move fluid through the system.
Finally, mobile machines can run thicker viscosity multi-weight oils, which as opposed to arctic oils, are designed to better maintain their viscosity.