Hydraulic machine efficiency can vary, which means that making the right decisions can be the difference between an economical process and a much costlier system.
Knowing what factors contribute (or detract from) hydraulic efficiency can save loads of time and money, especially in the long run.
Hydrocarbon Fluid Viscosity: A Critical Variable in Efficiency
Oil viscosity is extremely important for hydraulic efficiency. Since the viscosity of hydro-carbon based fluids increases as temperature decreases, oil properties change also when the fluid is heated. This has a number of negative consequences, including lowered efficiency and increased friction.
There is no fluid where viscosity is level for given ranges of temperatures. For every piece of hydraulic equipment, there exists an ideal temperature range, where viscosity is attuned for maximum efficiency: the ratio to work in vs. work out will be the highest.
Therefore, it’s very important to account for hydrocarbon viscosity by considering the following four factors:
Environmental temperature
The temperature that the machinery operates in will provide an immediate impact on the efficiency of the machine. Once again, the hotter the ambient temperature, the thicker the oil will be.
Unfortunately, it’s difficult to control environmental temperature for outdoors equipment. Ambient temps in these cases may have to be accounted for and controlled through other means.
Internal Cooling Systems
Hydraulic oil coolers are a staple for most settings where the equipment is used. The installations remove excess heat from engines, furnaces, and sometimes even surrounding environment.
Cooler selection can be complex and may require lots of planning, with the process dependent upon the type of system used. Water cooled systems are a relatively inexpensive option, but require a constant source of water. Other cooler types include refrigerated chillers and evaporative cooling towers.
Fluid Native Viscosity
Due to the wide range of applications of hydraulic equipment, choosing the right fluid is unfortunately not always easy. Varying factors, such as the severity of the duty cycle and the operating temperature ranges, should determine what fluid is best for an application.
Also, it will depend on whether the system is used indoors or outdoors. Indoor applications are generally a little gentler allowing a conventional anti wear hydraulic oil with the appropriate viscosity. However, things get more complicated in the outdoors where the majority of hydraulic equipment can be found. In these environments, hydraulic fluids typically require a high viscosity index.
Equipment Efficiency
Temperature isn’t everything; machine design largely impacts efficiency. The built-in efficiency reflects the mechanisms within the machine where power is affected, including certain valves and controls. Surface areas and other features, including pipes and hoses, may also affect the efficiency.
For conditions that might increase oil viscosity and reduce system efficiency, it often makes more sense to procure equipment which is more efficient. The long-run benefits are more likely to offset the difference in the upfront costs.