The increasing stringency of hydraulic system performance requirements means that more attention must be paid to all fluid properties. Unfortunately, there are some important properties that are often overlooked by designers. Compressibility, or bulk modulus, is one of these. Considering that bulk modulus is a property which can affect overall system performance, it is not a factor that should be ignored.
One of the most common concerns about oil is whether or not it’s possible to over-filter it. Some are of the opinion that maximum filtration is the best option, while others say that less is more. So which is the right answer? Increased life expectancy of equipment has been the result of using cleaner oils. However, there are also considerations which need to be made if the goal is to meet ISO cleanliness codes.
The degradation of oil is inevitable, regardless of the machine in which it is used. This is because, over a period of time, contaminants will enter the oil, causing damage to internal components, hydraulic seals, O-rings and the like. When lubricant degrades, an entire system and hydraulic pressure can be affected, leading to reduced reliability and performance of equipment.