In 1977, Ken Olsen, the founder and CEO of Digital Equipment Corporation
(now part of Hewlett-Packard), said:
"There is no reason for any individual to have a computer in his home."
You are probably wondering what this has to do with hydraulics. Well, in response to a
recent "Inside Hydraulics" article on Magnom magnetic filtration technology, an experienced
contamination-control practitioner wrote to me and said:
"The use of any magnetic device in a lubrication or hydraulic system is not necessary.
If the ISO code is correctly maintained using conventional filtration, then there is no
part for these devices to play."
The "computer" Ken Olsen had in mind back in 1977 was not the modern personal computer -
the desk top device many of us use at home today to play games, send and receive e-mail,
make music CDs, store photographs and keep track of the family finances.
Similarly, the magnetic filtration devices of yesterday that my learned colleague is referring
to don't resemble the Magnom technology. Fact is, Magnom has already been adopted in several
- A leading Formula One Racing Team uses Magnom on the lube-oil system of their F1 transmissions.
- At least one major filter manufacturer is developing filter housings that combine a Magnom magnetic element with a conventional filter element.
- A major construction equipment manufacturer has committed to long-term trials of Magnom on their machines' hydraulic systems.
A hydraulic application where Magnom offers unique benefits is the case drains of piston pumps
and motors. Installing conventional barrier filters in case drain lines can cause
problems as a
result of excessive case pressure. For this reason, I only ever install 125-micron filters on
pump and motor drain lines. These are brass mesh; spin-on type filters which should be grossly
oversized for the expected flow rate. The downside is that particles smaller than 125 microns
pass through this filter unobstructed.
Installing a Magnom unit immediately upstream of the 125-micron filter facilitates the capture
of ferromagnetic particles - which can account for up to 90 percent of all particles suspended
in the oil, down to sub-micron levels. The typically low oil viscosities and flow rates present
in case drain lines enhance the separation efficiency of the magnetic element. And according to
its manufacturer, the patented magnet arrangement of the Magnom eliminates particle wash-off
under surge flow conditions.
Wear particles originating from a pump or motor and captured by the Magnom in this configuration
are likely to be in their original state - having avoided being reworked in other parts of the
system. This improves the results of analytical ferrography and therefore the ability to
determine the source, cause and severity of the wear. In the case of a low speed, high torque
hydraulic motor, which may be worth tens of thousands, or even hundreds of thousands of dollars,
accurate component condition analysis can be invaluable.
Further reading on magnetic filtration is available here. More information on Magnom
technology is available at www.magnom.com.
"Thanks for the great work on the two publications, Insider Secrets to Hydraulics and Preventing Hydraulic Failures. I have been in the hydraulics business for the past 20 years and it is very difficult to find any decent material on hydraulic maintenance, troubleshooting and failure analysis. These two books cover it all in easy to understand language... I conduct hydraulic training courses and plan to purchase copies to distribute to my students to share your practical approach to understanding a not so understandable subject."
Paul W. Craven, Certified Fluid Power Specialist
Motion Industries, Inc.