Choosing the Right Hydraulic Filter

Are you in need of a new hydraulic filter? Choosing the right one comes down to knowing the application for which you’re using it, and the differences among the types of filters available.

Here is some information from a hydraulic service in Minnesota to help you ensure you get the right kind of filter for your needs.

The types of filters to choose from

Your first step should be looking at the different categories of filters available. Here are the main options you’re going to want to consider:

  • Suction filters: Suction filters are filters you put inside the tank to filter out bolts, rags or other items you accidentally drop into the reservoir. These are very basic filters that you are not going to be able to use to filter the fluid to the extent that it achieves ISO code standards.
  • Return filters: These filters clean the oil before it returns to the hydraulic reservoir, which keeps your reservoir clean and completely free of dirt particles that could cause the system some harm. Return line filters are most frequently used in open loop applications, and must be rated at the ISO code required by your particular system.
  • Pressure filters: These filters are highly recommended because they are placed in the system after the pump. This means if your pump ends up failing, all the components downstream of the pump are still protected, thanks to the pressure filter. These filters must be rated for the running pressure of your system and the ISO code that is applicable.

Note that while you do not necessarily need to use all three of these types of filters in the same hydraulic system, you should at least have a pressure filter or a return line filter in every application to ensure your fluid maintains the appropriate cleanliness standards that cannot be achieved with only a suction filter.

Determining the correct pressure drop

Once you’ve decided the kind of filter you want to use, you’ll also need to know the pressure drop through the filter. The majority of pressure filters and return filters have what’s called a “bypass,” an element that shields the system if the filter gets clogged up with debris. This bypass gives the oil the ability to pass the filter element and keeps the system running even if the oil isn’t being filtered.

Of course, it’s important to keep in mind that this is unfiltered oil, so while this feature does prevent you from experiencing some inconvenient downtime, it’s still important you keep up with proper filter maintenance steps.

The dirtier the filter becomes, the more pressure it takes to force the oil through the element. When the pressure reaches a certain level, it becomes inefficient, meaning you’re wasting power in the system.

When selecting the size of your pressure filter, you should have the goal of keeping the pressure drop under 10 PSI.

M & M Hydraulic Company has been handling a variety of hydraulic system needs for over four decades. For more information about choosing a hydraulic filter, contact our hydraulic service in Minnesota today.

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