Hydraulics Friendly Equipment

What kind of life should you get from your hydraulic components?

The best answer we can give to that question is "it depends."

Most companies manufacturing or selling equipment want their equipment to provide trouble-free operation until after the warranty expires.

And many manufacturers and dealers want their products to operate far enough past the warranty period that the service life exceeds their customers' expectations.

But the people who buy that equipment? Most would like it to operate for as long as possible - hopefully for many years after the warranty expires.

Unfortunately, if a manufacturer designs equipment to operate for the longest possible amount of time, they run into 3 issues:

  • 1) manufacturing equipment to operate as long as possible adds to the equipment's cost, so your equipment will be more expensive than that of your competitors and you'll probably lose sales;
  • 2) with your equipment's components operating as long as possible, you'll sell fewer replacement parts;
  • 3) your customers won't buy replacement equipment as often and you'll have fewer sales.

In other words, designing equipment to operate for the longest possible amount of time is going to reduce sales and profits.

Making equipment more hydraulics friendly.

We use the term "hydraulics friendly" to describe things that help a piece of equipment's hydraulic components function well for as long as possible. While most maintenance personnel would prefer their equipment be completely hydraulics-friendly, the reality is that a piece of hydraulics-friendly equipment will have a higher purchase price than its competitor's product. Since many purchasing departments make their buying decisions based on that initial purchase price, there's a good chance the equipment you have is not as hydraulics friendly as it could (or should) be.

For example, every hydraulic system has a reservoir that holds hydraulic fluid.

Basic Hydraulic Demo Circuit 001 Basic Hydraulic Demo Circuit 001 Basic Hydraulic Demo Circuit 001

If you had x-ray vision and looked at a hydraulic reservoir, you'd see there's always a layer of air on top of the fluid in the reservoir:

Basic Hydraulic Demo Circuit 001 Basic Hydraulic Demo Circuit 001 Basic Hydraulic Demo Circuit 001

And, with your x-ray vision, you would see air being pushed in and out of the reservoir as the hydraulic cylinder operates:

   Air moving in and out of hydraulic reservoir Air moving in and out of hydraulic reservoir Air moving in and out of hydraulic reservoir

The air around us carries particles that are too small to see, but big enough to damage hydraulic components. The size of these very small particles is often measured in microns, and most of us can't see particles smaller than 40 microns.

Inexpensive air filterThe most common cause of hydraulic component failure is contamination, and in order to help protect hydraulic fluid from airborne contamination, all air entering a hydraulic reservoir should pass through a filter. Most equipment manufacturers feel an inexpensive 40 micron filter not only cleans the air well enough that airborne contamination won't make the pump fail before its warranty expires, but will probably clean the air well enough so the hydraulic pump's life will exceed their customer's expectations.

But even though some sort of magnification is needed to see particles smaller than 40 micron, those small particles can damage hydraulic pumps and other hydraulic components. In fact, as a general rule, hydraulic pump manufacturers want all fluid entering their pumps filtered to 10 micron (about half the diameter of an average white blood cell).

So to design "hydraulics friendly" equipment, one thing you might do is specify 10 micron air filters instead of 40 micron air filters. Doing so would help your pump get the longest possible life.

But 10 micron air filters are more expensive than 40 micron air filters, and since 40 micron air filters usually clean well enough to allow pumps and other components to operate past the warranty period, equipment manufacturers are quite happy to cut their costs a wee bit and use the less expensive 40 micron air breather. After all, if they used a more expensive 10 micron air filter, it might help the hydraulics last as long as possible and reduce their sales of replacement parts and new equipment.

However, if you own the equipment or are responsible for maintaining it, you might feel it is a good investment to use a 10 micron air filter to protect a pump that needs fluid filtered to 10 micron (especially if you've ever had a warranty claim denied because a hydraulic component failed due to contamination).

WARNING: Before replacing an air breather, be sure the pressure drop through the new breather is the same or lower than the pressure drop through the old breather (if you are not nodding your head and thinking "that's pretty obvious," please consult a fluid power specialist or engineer before making any changes to your air breather). An incorrectly sized air filter can cause catastrophic pump failure.

"Hydraulics friendly" isn't always cost effective.

There are dozens of ways to help make a piece of equipment more "hydraulics friendly." Some are easy and relatively inexpensive to implement, others require a very significant investment of time and/or money.

There are times when investing $20,000 to make a machine more "hydraulics friendly" is a no-brainer, and other times when a $150 change is a waste of money.

Our Basic Hydraulic training helps participants see ways to make their equipment more hydraulics friendly, and helps determine whether or not it makes sense to make those changes.

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