Purity of hydraulic fluids is key to the longevity, reliability and efficiency of the entire system. With the right filtration, the system is protected from damage, problems can be detected early by monitoring purity and the bottom line is that costs are saved.
But how do I know how clean my fluids should be?
Simply put: ask the machine and component manufacturers. Let's find out what that means below.
Step 1: Identify target purity
The manufacturers of hydraulic components often specify guidelines for the maximum permissible degree of contamination of their components. These guidelines, usually given as ISO codes, are based on extensive testing and should be considered when determining your ISO target codes.
If guidelines differ for individual components, it is certainly helpful to aim for the level of cleanliness required for the most sensitive component. After all, a chain is only as strong as it's weakest link.
If the machine and component manufacturer's specifications are missing, reach out to your local HYDAC contact, they will be able to help.
Once you have determined the target purity, you should also consider the operating conditions. These can affect the appropriate target ISO purity codes. For example, systems operating in dirty environments may require better filtration and lower target ISO codes to combat external contaminants.
The target purity, beta values and pore size can then be used to select the appropriate filtration.
Step 2: Choose the proper filtration
To ensure that the chosen filtration actually achieves the desired purity, oil purity should be monitored. Online laser particle counters are the easiest and most accurate way to do this.
But be careful! Not every hydraulic oil can be counted online with a laser particle counter. Highly additive oils such as gear oils, ATFs, STOUs and UTTOs can have a negative effect on laser particle counting. In addition, a laser particle counter does not recognize the difference between water, air, additives and actual solid particles.
If online particle counting is not possible, laboratory analyses determining the oil purity are the method of choice. In the laboratory, these oils can often be diluted with suitable solvents. In addition, the particle count result can be checked for plausibility using a patch test and a microscope.
Online monitoring or laboratory analyses can be used to determine the oil purity and check the effectiveness of the filtration. If the purity is not achieved, the filtration can be adjusted.
By regularly monitoring the oil cleanliness in the system, trends can be detected and potential problems, such as increased contamination build-up/ingress or filter system failure, can be prevented.
In a nutshell
Machines and component manufacturers specify a target cleanliness, or you can make do with the recommendations of our contamination handbook. The desired target cleanliness and the beta values can be used to determine the correct filtration. By monitoring the system using online measurements or laboratory analyses, the effectiveness of the filtration is checked and can be adjusted if necessary.
If you need further help with determining your cleanliness limits or require expert advice on filtration, don't hesitate to click the contact button below or reach out to your local HYDAC representative 😊
This work is licensed under CC BY-NC-SA 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/4.0/