Filter Cart FAQ’s

How do I order a Kaman Filter Cart?

The Kaman Filter Cart can be ordered on KamanDirect.com or through your local Kaman branch.
The part number is 634 under manufacturer "KIT: Fluid Power"

I have an in-line filter on my system, why do I need an off-line filtration?

Off line filtration or polishing loops can reduce contaminants in even the best-designed systems. The Kaman Filter Cart will pickup particles in remote areas in a reservoir that the system filters may not reach. In addition a constant flow rate across the filter will clean the oil better with the same micron rated filter than short surges of oil.  Off-line filtration can be operated while the power unit is not on during shut down. There are many cases in which we have lowered an ISO code by adding off line filtration.

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What micron level filter element is right for my system?

This will depend on some inter-related factors, such as the complexity of your system (higher pressure demands a cleaner system) as well as the operating conditions in your plant. Select a cleanliness level that corresponds the component(s) in your system that are the most sensitive to contamination. The owners/operators manuals will typically give you the required rating, or you can contact a Kaman Certified Fluid Power Specialist to help you determine the right filters for your system. Filter placement is also critical. 

The Kaman Filter Cart uses a two-stage design utilizing a 25-micron pre-filter and a 3-micron final filter assembly as standard equipment. The 25-micron filters collect the larger particles while the 3-micron does the polishing.

Not all filter elements are created equal, all filter elements used on the Kaman Filter Carts are a Beta ratio 200 or greater. The Beta rating is an industry standard way of rating an element’s actual performance. The Beta ratio is obtained by counting contaminant particles in the inlet oil, then counting the particles in the outlet oil after it passes through the element. The formula for the Beta ratio is particle count in divided by the particle count out. Beta 200 means that for every 200 particles that go into the element only one comes out or it removes 199 out 200 particles. This is superior filtration don’t except less.

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I heard someone say that new oil is dirty?  How can that be?

Oil is dirty, even when new (unless you specifically order it filtered to an ISO rating). Processing, handling, storage, etc. combine to contaminant new oil to a level that will cause system problems. This level of contamination will void most new component warranties. The best way to prevent contamination is to filter the new oil using the Kaman Filter Cart with the standard 25 micron pre-filter and 3 micron polishing filter while you transfer it from the supplier’s container to your system reservoir. Perform an oil analysis on your next barrel of new oil to determine the level of contamination. Oil analysis kits are available from your local Kaman representative. Order number PLT OILANALYSISKITS for a complete breakdown of properties and contaminants.

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Why does oil analysis go hand in hand with the Kaman Filter Cart?

Hydraulic oil very seldom wears out, unless it’s subject to extreme heat chances are it’s just dirty and can be rejuvenated as opposed to discarded. The only way to know if your oil can be saved is to perform an oil analysis to determine the level of contamination and overall condition of the anti-wear, anti-foam agents that are suppose to be in the oil. We have saved many customers money by taking this approach, 3000 gallons in one instance saving our customer over $12,000 in replacement oil costs. Oil analysis kits are available from your local Kaman representative. Order number PLT OILANALYSISKITS for a complete breakdown of properties and contaminants.

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I have good maintenance practices, and regularly change system filters, do I really need external off-line filtration?

Yes, system filtration usually cannot reach all areas that collect contaminants. Hydraulic systems produce contaminants in normal use in addition to ingression from valves, cylinders, tank breathers, etc.  Even the best-designed and operated systems will develop contaminants that contribute to abrasive wear in pumps, motors, valves and cylinders. Most of these contaminants can be removed using the Kaman Filter Cart.  Off-line filtration removes 100% free air out of the oil. In addition a constant flow rate across the filter will clean the oil better with the same micron rated filter than short surges of oil.  Off-line filtration can be operated while the power unit is not on during shut down. There are many cases in which we have lowered an ISO code by adding off line filtration

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My oil does not come into contact with water, how am I getting water into my system?

Water contaminants oil predominantly through atmospheric (humidity) sources. Condensation is the most common next to an unsealed reservoir placed outdoors. Water causes the most problems, as it rusts components, combines with scale to create a sticky sludge that causes up to 90% of all servo valve failures. With the optional water removal element installed on your Kaman Filter Cart the water will be removed leaving your oil clean and ready to use again. Each water removal element will hold 1 quart of water!

For larger amounts of water, a dehydrator must be used.  This will filter particulate as well as remove dissolved and free water.  Contact Kaman for more information. Excessive water is almost always present in steel and paper mills as well as other heavy process driven industries. 

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My servo valves stick, can you offer ideas why?

Your oil condition is probably the principle cause, moisture is one of the worst offenders. Contaminated oil contributes to 90% of servo valve failure. You can improve your oil’s condition with the Kaman Filter Cart by installing two water removal elements as pre-filters and the recommended micron level element (from your owner’s manual) for the final polishing, filtering out water, particulates and accumulated sludge. Correcting sticky servo filters resides primarily with filtering and conditioning of the existing oil.

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Why is an “internal” gear pump so superior to a standard gear pump?

This is not the standard hydraulic gear pump like those     used on other filter carts. Our gear pump utilizes a “Gear within a Gear” or internal design - For nearly seventy years, this design has demonstrated it’s effectiveness in handling a broad range of applications, and reducing wear. Because the rotor is rotating at a fraction of the motor speed, wear and noise are reduced, and fluid flow into the gears is more effective. This extends the service life of the pump and makes pumping of higher viscosity fluids possible. True, three tooth engagement between the rotor and pinion provides superior flow characteristics. These operating characteristics play an important role in minimizing overall capital investment, and operating expenses.

Why do I need the 3-way bypass valve that’s standard equipment on the Kaman Filter Cart?

There will be times when you merely want to transfer the oil and not filter it, waste oil for example. Why run waste oil through your filters? The system utilizes a 3-way ball valve to transition from filtering to transfer mode. The process takes between 3-5 seconds to perform, saving your filter elements while saving you money.

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Lot’s of filter carts have drip pans, what differentiates the Kaman Filter Cart drip pan?

No matter what type of filter is used, there is always some oil spillage when changing elements, hence the need for a drip pan. The Kaman Filter Cart’s drip pan has a rear drain plug preventing the need to swab out the spillage or turn the cart on its side to drain it.

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Why Stainless Steel wands over other types of wands?

Stainless steel wands offer excellent resistance to corrosion and pitting as compared to plated, painted or coated wands. Plastic wands tend to be brittle, breaking easily.  Stainless Steel offers better protection by not reintroducing contaminants into your oil.

What if I want to transfer and/or filter other than petroleum based fluids?

The Kaman Filter Cart with it’s standard 25 micron pre-filter and 3 micron polishing filter can handle a wide range of fluids. Due to the many variations of liquids and their effect on seals, etc., these are handled on a case-by-case basis. Contact a Kaman Certified Fluid Power Specialist to help you with your application.

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We welcome your questions please submit to:

Rod Willeford- Certified Fluid Power Specialist
Kaman Product Support Group
Ph. (509) 777-4109
Fax (509) 534-9393
Email rod.willeford-kit@kaman.com