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Portable Filtration…Specifying the Appropriate Features

Dan Freeland


Considerations when selecting a system for your application

So, you have decided, by oil analysis or by ROI analysis, that a filtration system purchase is in your future. Wise decision!

It makes logical sense that in most instances the case can be made that filtering your oil will indeed better protect equipment and extend equipment and lubricant life. But now you must choose a filtration system that best suits your needs. Let’s take a look at some considerations to take into account when choosing a portable filtration system.

Where are you going to use your filtration system?

If you plan to use your filtration system in your lube room, there are many options. For 55-gallon drums, there are drum pumps with filtration affixed to them so filtration can happen right at the point of dispensing. These units often have a recirculation option to filter stored oil drums. Hand-held units can also be equipped on top of these drums. Filtration carts should be used for larger totes in your lube room.

Other items to consider in the lube room are:

  1. Electric or Pneumatic
    • Power supply available?
  2. Power availability
    • 100V or 220V
    • 50 Hz or 60 Hz
    • 15- or 20-Amp Circuit
  3. How many different oils
    • Dedicated system for each oil will reduce any chance of cross-contamination

If you plan to use your portable filtration throughout the plant, which is inherently part of their versatility, there are other factors to look at. Review obstacles, safety factors, and point of use locations to determine the best form of portability. Plant layouts can squeeze critical equipment into some tight spaces; or if the equipment is accessible, the inlet and outlet ports are difficult to reach. A large filter cart may not be able to maneuver into proper position.

Here are some items to consider for location:

  1. Equipment Accessibility
    • Is a cart going to be able to get to the location or is a hand-held system a better option? (i.e. – narrow catwalks, stairs, ladders, etc.)
    • Is the equipment to be filtered not on the main floor? How does a cart get up or down levels, or is a hand-held system a better option for transportation?
  2. Volume of the oil in the equipment
    • Carts generally have higher flow rates than hand-held systems because the motor and pump are more robust. The amount of time a filtration unit needs to run should be considered. Typical industry standards suggest 6-8 times an oil volume should be filtered through to consider it is filtered completely.
      EXAMPLE: 100-gallon reservoir x 8 times through – 800 gallons. Using a cart with a 4 gpm pump, that cart will need to run for 200 minutes or 3 hours and 20 minutes. A 1 gpm hand-held system will take 13 hours and 20 minutes.
    • Carts also have larger and/or more filters than hand-held systems to do the job. This cuts down on time changing filters out.

What are you going to filter?

Oil viscosity can play a significant role in selecting a portable filtration system. Hydraulic oils are thinner, less viscus fluids than gear oils for example. The equipment necessary to filter hydraulic fluids, up to approximately ISO VG 220, is much less costly than trying to pump an ISO VG 680 gear oil through a filter at room temperature. Therefore, hydraulic oil only carts are typically less expensive than systems that can handle gear oils. That being said, fluid temperature in turn plays a significant role in fluid viscosity. An ISO VG 680 oil at room temperature increased to 100ºF running temperature, reduces the 680 cSt to less than 200 cSt. Once again, how many different oils you are going to filter and oil volumes are going to play into your decision.

Some lubricant considerations:

  1. Oil Viscosity
    • Hydraulic Oil
    • Gear Oil
  2. Oil temperature when filtering related to viscosity
  3. How many different oil types?
    • Dedicated system for each oil will reduce any chance of cross-contamination
  4. Volume of oil to filter

What is your cleanliness target?

You will need to select the filters to be installed on your system. Let us assume for the moment your decision to purchase a filtration unit was based on something you’ve seen, read, or heard somewhere along the way; but you don’t know where to begin. You can start with the application the oil is going to serve. The manufacturer of the equipment may have an oil cleanliness recommendation in the OEM manual, but these can be difficult if not impossible to locate. For Particle contamination, there are many general published guidelines, typically by filter manufacturers, that can get you in the ballpark of what filters to choose. System manufacturers can also aide in the selection if necessary. Choose a filter size that is within the appropriate range for the application.

It’s important to note that not all filters are created equal, so buyer beware if you choose price as the primary decision-making factor. When using portable filtration, it is recommended to use absolute rated filters which have the highest efficiency (Beta 200 = 99.5% efficiency) as opposed to nominal rated filters (Beta 2 = 50% efficiency).

Water contamination is a bit trickier. Water content is typically measured by a Karl Fischer test. This is generally done by an oil analysis lab. It is recommended to get your oil analyzed for water content to determine if a water filter is necessary. You can also trend your progress in particulate and water contamination reduction with subsequent oil samples being analyzed.

What else do you want from your filtration system?

Of course, you want it to filter your oil. But what else? Well we just talked about oil sampling. Your filtration system should come equipped with some way to take samples for analysis. Oil sampling ports are options on most systems.

Some filtration units come with metal wands for inlet and outlet hoses. This is not necessarily the best way to “connect” to your tank or equipment. The wands can be contamination magnets when not in use and don’t support best practices. Consider ordering quick connect hydraulic couplers for your system. You will need to outfit your tank or equipment with the mating couplers, but in the end will make using your filter cart much easier and cleaner.

Manual by-pass valves are also an option on most systems. This allows the user to utilize the functionality of the pump without having the oil pass through the filters. Say, for instance you have a larger reservoir that is chemically spent or at the end of its useful life. You could spend a lot of time waiting for the equipment top drain by gravity, or you could put the cart into by-pass and pump out the spent oil much more efficiently.

Other Options:

  1. Sample Ports
  2. By-Pass Valves
  3. Quick Connect Couplers

What are you waiting for?

Doing some relatively straightforward upfront work when selecting a portable filtration system will help you to select the optimal set-up for your applications. This will jumpstart any filtration program and make using your selected unit a worthwhile experience. Using a portable filtration system effectively, along with a basic oil analysis program, will extend the functional life of your oil – and ultimately extend equipment life.

Not sure what system you need?

We’re happy to help you figure out which portable filtration system is right for your plant. You can also watch our video that walks you through the key considerations when selecting a portable filtration system.